CROSS-REFERENCE TO RELATED APPLICATIONS
FIELD OF INVENTION
[0002] The present invention relates to the field of autonomous vehicles and, in particular,
to a drive system or module for a submersible autonomous vehicle, and even more particularly,
to an add-on drive system or module for a pool cleaning robot.
BACKGROUND
[0003] Autonomous vehicles are being introduced into an ever increasing number of facets
of daily life in order to automate various tasks, such as cleaning a pool, cleaning
an indoor space, and maintaining a lawn. Additionally or alternatively, autonomous
vehicles (also referred to herein as robots) may be used for entertainment, law enforcement,
and a wide range of other purposes. There are many types of autonomous vehicles; however,
many of these autonomous vehicles, such as submersible autonomous vehicles (e.g.,
pool cleaners) only include one type or manner of propulsion at least because it is
often not economically efficient to include a second type of propulsion (e.g., a second
drive system).
[0004] For example, since pool cleaners often require a pump or suction system to clean
a pool, it is often economically efficient (and efficient in terms of space and size)
to utilize the pump system for both cleaning and propulsion (e.g., as opposed to including
a dedicated/second drive system). As a more specific example,
U.S. Patent No. 8,273,183, incorporated herein by reference, discloses an autonomous pool cleaner with a water
jet propulsion system that draws in water for both cleaning and propulsion. In order
to utilize the drawn-in water to propel or move the pool cleaner along a surface,
the pump system discharges the drawn-in water, as a pressurized stream, at an acute
angle with respect to the surface. In the particular example of
U.S. Patent No. 8,273,183, the pressurized stream may be discharged in different directions to control steering
of the submersible autonomous vehicle. Similarly, many indoor cleaning robots many
only include two powered wheels. However, over time, these drive/propulsion systems
will typically require maintenance, part replacement, or some other repair due to
the wear and tear associated with repeated usage.
[0005] Unfortunately, since autonomous vehicles may be quite complicated and may be pre-assembled,
maintenance frequently requires an end-user to transport the robot to a mechanic,
manufacturer, or some other specialized technical service provider familiar with the
drive system and/or the entire robot. Alternatively, an end-user may attempt to disassemble
a robot and/or drive system with tools to try to assess and fix the problems on their
own. However, often, an end-user can only disassemble a small portion of the robot
(or a drive system) because the major components have been coupled together with specialized
tools (e.g., tools machined or developed specifically for assembling/disassembling
this particular robot). Moreover, even if the end-user can determine the problem,
a part or portion of the drive system may be broken and, thus, may require a user
to identify and order the correct replacement part. Consequently, regardless of how
an end-user attempts to resolve a maintenance issue, an end-user will often be without
a working drive system (and robot) for an extended period of time. Since autonomous
vehicles are typically unable to function without a working drive system, this may
render the autonomous vehicle useless for an extended period of time.
[0006] Moreover, as technology advances, new parts, programming, and configurations may
be developed for robotic drive systems. These advancements may improve various aspects
of the robots (e.g., battery technology, ability to navigate different terrains, surfaces,
increased robot efficiency or power, etc.); however, most robots cannot be upgraded
and, instead, must be replaced to obtain a technological upgrade. In fact, many robots
cannot even be reconfigured and, thus, are only useful for certain, specific tasks
(e.g., cleaning certain types or shapes of pools) and may require a user to buy different
robots for different tasks. For example, many pool cleaning robots are provided by
the manufacturer to the end-user in a compact, ready-to-use way, and the end-user
is given little or no choice on how to configure of the robot. Then, if a user notices
a problem with the drive system of the robot, the user has no options for adjusting
the drive system to try to overcome the problem (and the user may also be unable to
return or exchange the robot since the problems may only become apparent during extended,
post purchase, use).
[0007] In view of at least the aforementioned issues, a self-contained drive module that
can be removably attached to an autonomous vehicle as a replacement or supplemental
drive system is desirable.
SUMMARY
[0008] The present invention relates to a drive system or module for an autonomous vehicle
and, in particular, a submersible autonomous vehicle. The drive module includes a
drive motor that drives a propulsion element (e.g., a wheel or wheels, or an endless
track) to propel the robot along surfaces (lawn, carpet, flooring, pool surfaces,
pool deck, etc.), whether above or below water (e.g., submerged). Consequently, the
drive module is mechanically isolated from any mechanical systems (e.g., gear trains)
included within the body of an autonomous vehicle to which the drive module is coupled
(e.g., a "host" autonomous vehicle). In accordance with at least one embodiment of
the present invention, the drive module is also electronically isolated, insofar as
the drive module need not be operatively coupled (via a wired or wireless connection)
to any systems included within the body of a robot. Instead, a self-contained drive
module can simply be removably coupled to an autonomous vehicle and operate independently.
Alternatively, a drive module may be operatively and/or electronically coupled to
systems included within the body of a robot for specific requirements, such as to
draw power from or supply power to electronic components included within the body
of the robot, and/or to retrieve/receive/communicate control instructions to and from
a control system included within the body of the robot (or electrically coupled to
the robot).
[0009] The present invention avoids problems posed by known autonomous vehicles (e.g., maintenance
and configuration issues) by providing a modular drive system that can be configured
for many different autonomous vehicles. Consequently, if the drive system included
on an autonomous vehicle malfunctions, requires maintenance, or is otherwise inadequate
for some reason (e.g., obsolete battery technology), the drive module presented herein
can be coupled to the autonomous vehicle to supplement or replace the drive system
of the host autonomous vehicle. This minimizes the downtime of autonomous vehicles
with broken drive systems while also maximizing the flexibility of a particular autonomous
vehicle (e.g., to complete a wide variety of tasks).
[0010] Put another way, the drive module presented herein allows existing autonomous robots
and, in particular, submersible robots, to be easily upgraded or reconfigured. As
an example of an upgrade, the drive module may include the newest battery technology
(e.g., smaller and/or more powerful batteries) and may be utilized to upgrade the
battery life of an existing submersible, autonomous robot. The battery within the
drive module could be a rechargeable battery that could, optionally, be removable
from the module and could be recharged in a charging station via a contact-based charging
system or a contactless charging system. At the same time, the drive module presented
herein provides a drive system that can be easily maintained and/or fixed without
removing an entire robot from service (e.g., a malfunctioning drive module of the
present invention can simply be replaced with another drive module of the present
invention).
[0011] As is described in further detail below, the drive module can be coupled to an autonomous
vehicle with rapidly releasable coupling mechanisms, insofar as a rapidly releasable
coupling mechanism includes any coupling that can be rapidly achieved without the
use of any specialized tools (e.g., without any tools) and without any special skills
or knowledge, such that a rapidly releasable coupling mechanism can be engaged or
disengaged easily by an end-user. For example, a rapidly releasable coupling mechanism
may include snap-fitting mechanisms, tongue and groove mechanisms, resilient mechanisms
(e.g., detents, living hinges, etc.), half-turn or quarter turn latches and/or plug
and socket mechanisms. Consequently, each drive module can be quickly and easily replaced
by an end-user. In fact, in some embodiments, the components of the drive module presented
herein may also be coupled together in a manner that allows each component to be individually
removed from the drive module without removing or disassembling other components to
simplify maintenance.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] To complete the description and in order to provide for a better understanding of
the present invention, a set of drawings is provided. The drawings form an integral
part of the description and illustrate an embodiment of the present invention, which
should not be interpreted as restricting the scope of the invention, but just as an
example of how the invention can be carried out. The drawings comprise the following
figures:
FIG. 1 is a front perspective view of an example autonomous swimming pool cleaner
including at least one drive module configured in accordance with a first exemplary
embodiment of the present invention.
FIG. 2 is a front perspective view of another example autonomous swimming pool cleaner
including at least one drive module configured in accordance with a second exemplary
embodiment of the present invention.
FIG. 3 is a side, sectional view of the drive module of FIG. 2.
FIGs. 4A-C are side perspective views of a main body of the pool cleaner and the drive
module of FIG. 2 and, collectively, FIGS, 4A-C schematically illustrate mounting the
drive module on the main body, according to an exemplary embodiment of the present
invention.
FIG. 5 is a side, sectional view of the drive module of FIG. 1.
FIG. 6 is an exploded, side perspective view of the drive module of FIG. 1.
FIG. 7 is a front, sectional view of the drive module of FIG. 1.
FIG. 8 is a flow chart illustrating operations of the drive module of FIG. 1 during
propulsion of an autonomous vehicle.
FIG. 9 is a top plan view of another embodiment of a drive module for an autonomous
vehicle, such as the autonomous vehicle of FIG. 1 or FIG. 2.
DETAILED DESCRIPTION
[0013] The following description is not to be taken in a limiting sense but is given solely
for the purpose of describing the broad principles of the invention. Embodiments of
the invention will be described by way of example, with reference to the above-mentioned
drawings showing elements and results according to the present invention.
[0014] Generally, the drive module presented herein includes a propulsion element, such
as a wheel or endless track, and a motor configured to drive the propulsion element.
In some embodiments, the motor may be coupled to the propulsion element via a gear
train, power train, or other such components. Additionally, the drive module includes
a controller that is operable to control the drive motor (e.g., to control speed and
direction of a motor shaft). In some embodiments, the drive module also includes a
second motor configured to engage and drive an internal system of an autonomous vehicle
on which the drive module is attached (and, thus, the second motor may be referred
to as an internal system motor or pump motor) and the controller may also be operable
to control the second motor.
[0015] As is explained in further detail below, in some embodiments, the drive module may
also alternately or concurrently include a communications module that allows the controller
to communicate with a control system included in an autonomous vehicle to which the
drive module is coupled (e.g., a host autonomous vehicle) and/or with other drive
modules that are also coupled to the host autonomous vehicle. Consequently, a drive
module may receive instructions (via a wired or wireless connection) from, send feedback
or control instructions to, or otherwise communicate with the control systems or the
other drive modules included on or within the body of a host robot (e.g., a submersible,
pool cleaning robot). Additionally or alternatively, the drive module may include
memory with drive instructions for controlling the drive motor.
[0016] Similarly, in some embodiments, the drive module may draw power from power systems
of a host robot, but in other embodiments, the drive module may include an internal
power source. In still further embodiments the drive module may draw power from a
host robot and also include an internal power source. Regardless, the drive module
may be configured to power a motor, controller, and any other powered components included
in the drive module. Additionally or alternatively, the drive module may be configured
to provide power to electronic systems included within the host autonomous vehicle.
Consequently, if the drive module includes enhanced battery technology (as compared
to battery technology included on the existing host autonomous vehicle), the drive
module may provide longer battery life, enhanced power attributes, and any other such
advantages afforded by the enhanced battery technology to the existing host autonomous
vehicle. As mentioned above, the drive module's battery could be recharged in a charging
station via a contact-based charging system or a contactless charging system.
[0017] The drive modules presented herein in accordance with the present invention may be
individually coupleable to an autonomous vehicle with rapidly releasable coupling
mechanisms, such as snap-fit mechanisms, or other similar mechanisms, such that each
drive module can easily be removed from the main body (e.g., without disassembling
other portions of the autonomous vehicle). Consequently, an end-user may easily remove
a drive module for maintenance, replacement, or repair. Additionally, if a robot has
a broken drive system, a user may simply install (or replace) a drive module onto
the robot, instead of taking the robot out of service for an extended period of time
for inconvenient and costly maintenance. One particular embodiment for individually,
releasably coupling an exemplary drive module of the present invention to a host autonomous
vehicle is described below in connection with FIGs. 4A-C; however, this is merely
an example and any rapidly releasable coupling may be used to couple any embodiment
of the drive module to a host autonomous vehicle.
[0018] In many known submersible autonomous vehicles, components of the autonomous vehicle's
drive system are distributed throughout the autonomous vehicle. Consequently, the
drive systems are not removable and are difficult to repair. Alternatively, some submersible
autonomous vehicles include components of a drive system (e.g., a motor) disposed
externally of a main body of the autonomous vehicle. However, these drive systems
are often interconnected with systems included within the autonomous vehicle (e.g.,
external components are electrically connected to a power source disposed within the
main body of the autonomous vehicle) and/or not removable, let alone easily removable,
from the main body.
[0019] Easy removal and replacement facilitate a do-it-yourself (DIY) approach and/or workaround
for maintenance and repairs, while also allowing an end-user to reconfigure or upgrade
an autonomous vehicle, if desired. For example, an end-user may easily reconfigure
an autonomous vehicle between different drive configurations, perhaps to add rear-wheel
drive to a front-wheel drive autonomous vehicle (thereby creating a four-wheel drive
vehicle) or to add traction propulsion to an autonomous vehicle (e.g., pool cleaner)
with jet or fluid propulsion. As another example, the drive module could be used to
provide the motive force for moving water around inside the submersible autonomous
vehicle (for cleaning a pool, for example). In this example, a shaft extending outward
from within the body of the submersible autonomous vehicle could be mated with the
drive module where a bladed-member, like a fan blade, attached to the end of the shaft
within the body of the vehicle can be driven by the motor within the external drive
module. Thus, the body of the submersible autonomous vehicle need not include any
internal motor or pump to operate. Put briefly, the drive module presented herein
allows the end-user to design and configure an autonomous vehicle according to their
needs, encouraging a DIY approach for improvement and reconfigurations.
[0020] Now referring to FIGs. 1 and 2 for a high-level description of two autonomous vehicles
including exemplary drive modules in accordance with the present invention. FIG. 1
shows an autonomous pool cleaner 10 including a drive module 100, while FIG. 2 shows
an autonomous pool cleaner 20 including a drive module 200. Although both of the depicted
autonomous vehicles are submersible pool cleaners, it is to be understood that the
drive modules described herein could also be installed on other types of autonomous
vehicles configured to travel along a surface (e.g., ground-based autonomous vehicles),
such as autonomous vacuums, autonomous lawn mowers, etc. Moreover, features incorporated
in one embodiment (e.g., drive module 100) could easily be incorporated into another
embodiment (e.g., drive module 200), or vice versa.
[0021] The particular pool cleaner 10 shown in FIG. 1 typically includes free-wheeling wheels
and is driven (e.g., propelled) via water jets exiting the top of the pool cleaner
at sharp angles. The free-wheeling wheels contact the inner surfaces of the pool (walls
and floor) and roll thereon as the water jets propel the pool cleaner 10. However,
in the illustrated embodiment, the two front wheels have been replaced with drive
modules 100 configured as wheels in accordance with the present invention. The drive
modules 100 are described in further detail below in connection with FIGs. 5-7, but,
generally, the drive modules 100 add a second propulsion system to the pool cleaner
10 that can be operated together with the jet (fluid) propulsion system included in
robot 10 or as an alternative to the jet (fluid) propulsion system. For example, the
drive modules 100 may drive the robot 10 in portions of the pool where the jet propulsion
system may struggle (e.g., certain corners and/or walls) and/or in situations where
the jet propulsion system is malfunctioning (e.g., when the jet propulsion system
is clogged). As is also described below in further detail, the drive modules 100 may
receive power from, supply power to, and/or communicate with systems included in the
robot 10 in order to work together and/or as an alternative to the jet propulsion
system included in robot 10.
[0022] By comparison, the pool cleaner 20 shown in FIG. 2 is typically driven by endless
tracks that receive power from a motor disposed within a main housing of the pool
cleaner 20, but have been replaced with or supplemented by self-contained drive modules
200. The drive modules 200 are described in further detail below in connection with
FIGs. 3 and 4A-C, but, generally, the drive modules 200 may include any components
(e.g., a power source, motor, controller with drive instructions, etc.) needed to
allow the drive modules 200 to propel the pool cleaning robot 20 without interacting
with any components or systems included in the pool cleaning robot 20. For example,
the drive modules 200 may include a complete power train housed therein and, thus,
may be mechanically isolated from mechanical systems included in the pool cleaner
20. Despite the mechanical differences between drive module 100 and drive module 200,
both drive modules may be sealed such that any electrical components, gears, or other
components that might be negatively impacted by exposure to water, are protected when
the robots 10, 20 are submerged under water.
[0023] Moreover, both drive modules may include a power source and necessary program instructions
to operate a power train and propulsion element included therein, if desired. For
example, the drive module 200 may include an internal power source and program instructions
stored in memory, so that the drive module may also be operatively and electronically
isolated from systems included in the pool robot 20. However, despite these capabilities,
in some embodiments, the drive modules may be operatively and/or electronically coupled
to systems of a host submersible robot. For example, the drive module 200 may be electronically
coupled to a power system within the body of the robot 20 in order to receive power
from the robot 20 and/or the drive module 200 may be operatively coupled to a control
system within the body of the robot 20 in order to receive drive instructions from
the control system. Moreover, these connections may allow a drive module (e.g., drive
module 200) to supply power and/or control instructions to systems included within
a host autonomous robot (e.g., a submersible pool cleaner without on-board intelligence),
possibly allowing the autonomous robot to be detached from a tether or cord that attaches
the cleaner to an external source of power and/or instructions.
[0024] FIG. 3 depicts the drive module 200 included in FIG. 2, according to an exemplary
embodiment of the present invention. As mentioned above, the drive module 200 is a
self-contained drive module 200 and, thus, includes a controller 280 that is configured
to control a motor 270 to drive a propulsion element 260. For example, the controller
280 may control the rotational speed and rotational direction of a motor shaft for
any desirable periods of time. The controller 280 and motor 270 are disposed within
a housing 202 and the propulsion element 260 is disposed externally of the housing
202. In at least some embodiments, the housing comprises a water-tight enclosure and,
thus, protects the controller 280, the motor 270, and any other components disposed
therein from water exposure when the drive module 200 is utilized with a submersible
robot.
[0025] In this particular embodiment, the propulsion element 260 is an endless track extending
around the housing 202 and the drive module 200 includes a gear train 272 and drive
gears 274 configured, through well-known mechanical coupling methods to impart motion
from the motor 270 to the propulsion element 260 so that the propulsion element 260
engages and rotates against a surface to create a driving or propelling force. The
drive module may also include a guide pulley 276 configured to stabilize the endless
track 260. However, in other embodiments, the drive module 200 may include any elements
or components to stabilize or support the propulsion element 260 and impart motion
from the motor 270 to the propulsion element 260. Moreover, in other embodiments,
the propulsion element 260 may be any element that may engage and provide motion along
a surface. As an example, in some embodiments, the motor 270 may impart motion directly
to a propulsion element 260 configured as a wheel that engages and rotates against
a surface of a pool.
[0026] Regardless of the configuration of the motor 270 and propulsion element 260, the
controller 280 is generally configured to control the motor 270 and, thus, is generally
configured to control propulsion provided by the drive module 200. The controller
280 may include a memory 282 and a processor 284. While the figure shows a signal
block 284 for a processor, it should be understood that the processor 284 may represent
a plurality of processing cores, each of which can perform separate processing. Meanwhile,
memory 282 may include random access memory (RAM) or other dynamic storage devices
(e.g., dynamic RAM (DRAM), static RAM (SRAM), and synchronous DRAM (SD RAM)), for
storing information and instructions to be executed by processor 284. The memory 282
may also include a read only memory (ROM) or other static storage device (e.g., programmable
ROM (PROM), erasable PROM (EPROM), and electrically erasable PROM (EEPROM)) for storing
static information and instructions for the processor 284. In addition, the memory
282 may be used for storing temporary variables or other intermediate information
during the execution of instructions by the processor 284. Although not shown, in
some embodiments, the controller may include a bus or other communication mechanism
for communicating information between the processor 284 and memory 282
[0027] The controller 280 may also include special purpose logic devices (e.g., application
specific integrated circuits (ASICs)) or configurable logic devices (e.g., simple
programmable logic devices (SPLDs), complex programmable logic devices (CPLDs), and
field programmable gate arrays (FPGAs)), that, in addition to microprocessors and
digital signal processors may individually, or collectively, are types of processing
circuitry. The processing circuitry may be located in one device or distributed across
multiple devices.
[0028] The controller 280 performs a portion or all of the processing steps of the invention
in response to the processor 284 executing one or more sequences of one or more instructions
contained in a memory, such as memory 282. Such instructions may be read into memory
282 from another computer readable medium. One or more processors in a multiprocessing
arrangement may also be employed to execute the sequences of instructions contained
in memory 282. In alternative embodiments, hard-wired circuitry may be used in place
of or in combination with software instructions. Thus, embodiments are not limited
to any specific combination of hardware circuitry and software.
[0029] Put another way, the controller 280 includes at least one computer readable medium
or memory for holding instructions programmed according to the embodiments presented,
for containing data structures, tables, records, or other data described herein. Examples
of computer readable media are compact discs, hard disks, floppy disks, tape, magneto-optical
disks, PROMs (EPROM, EEPROM, flash EPROM), DRAM, SRAM, SD RAM, or any other magnetic
medium, compact discs (e.g., CD-ROM), or any other optical medium, or any other medium
from which a computer can read.
[0030] Embodiments presented herein include software stored on any one or any combination
of non-transitory computer readable storage media, for controlling the controller
280, for driving a device or devices for implementing the invention, and for enabling
the controller 280 to interact with a human user (e.g., an end-user). Such software
may include, but is not limited to, device drivers, operating systems, development
tools, and applications software. Such computer readable storage media further includes
a computer program product for performing all or a portion (if processing is distributed)
of the processing presented herein. The computer code devices may be any interpretable
or executable code mechanism, including but not limited to scripts, interpretable
programs, dynamic link libraries (DLLs), Java classes, and complete executable programs.
Moreover, parts of the processing may be distributed for better performance, reliability,
and/or cost.
[0031] Still referring to FIG. 3, the drive module may also include a power source/interface
294 configured to supply power to the controller 280 and motor 270 and a communications
module 292. As mentioned, in some embodiments, the drive module may be electronically
and operatively isolated. In these embodiments, the drive module 200 may not need
a communications module 292 and the power source 294 may be a battery or other such
power source that is configured to supply power to the controller 280 and motor without
receiving any continuous external power.
[0032] The communication module 292 may provide a two-way data communication coupling to
a pre-existing controller within the body of the autonomous vehicle. Wireless links
may also be implemented to communicatively couple the communication module 292 to
a pre-existing controller within the body of the autonomous vehicle and/or an external
source of instructions (e.g., external to the host autonomous vehicle, such as a base
station). In any such implementation, the communication module 292 sends and receives
electrical, electromagnetic or optical signals that carry digital data streams representing
various types of information.
[0033] Generally, the communications module 292 may provide data communication through one
or more networks to other data devices. For example, the communications module 292
of a first drive module may provide a connection to a communications module of a second
drive module (e.g., in a master-slave configuration). Additionally or alternatively,
as mentioned above, the communications module 292 may provide a connection to a pre-existing
system included within the body of an autonomous vehicle, such as a control system.
The connection may be through a "wired" communication channel or a wireless communication
channel or protocol, such as BLUETOOTH ®, or any other known form of wireless communication
feasible between sealed modules operating underwater, such as optical communication,
ultrasonic communication, and near-field communication. Even when utilized with a
submersible robot, a wireless connection may provide sufficient connectivity between
drive modules, a drive module and the host robot, etc., due to the proximity of these
parts.
[0034] In embodiments where the drive module 200 is electronically or operatively coupled
to an autonomous vehicle to which the drive module 200 is coupled (e.g. a host autonomous
vehicle),, the power source/interface may provide an electrical coupling to a power
system within the body of the autonomous vehicle and the communications module 292
may operatively couple the drive module to systems included within the body of the
autonomous vehicle to which the drive module 200 is coupled. Such coupling may be
achieved via a tether wire which passes from the drive module 200 into the body of
the autonomous vehicle. Moreover, such a coupling may allow the drive module 200 to
supply power and/or send instructions to systems of the host autonomous vehicle. For
example, if the host autonomous vehicle is a submersible pool cleaner that receives
power and/or control instructions from an external source (e.g., a pool cleaner without
any on-board instructions or power supply), the drive module 200 may replace or supplement
the external source. Advantageously, this may increase the battery life of autonomous
vehicle, allow for customized programming (e.g., by sending specific voltages and/or
pulses, at specific times, to a comparator, encoder/decoder, application-specific
integrated circuit (ASIC), etc. included in the host robot), and/or allow a submersible
robot to be untethered from an external power source/controller.
[0035] Now referring to FIGs. 4A-C for a description of how a drive module 200 of the present
invention may be rapidly releasably coupled to an autonomous robot. In FIGs. 4A-C
the drive module 200 is illustrated being coupled to a main body 22 of the robot 20;
however, it is to be understood that this is merely one example of a rapidly releasable
attachment and, in other embodiments, any drive module of the present invention may
be rapidly releasably attached to an autonomous vehicle in any rapidly releasable
manner so that other parts or assemblies included in the autonomous vehicle need not
be disassembled or rearranged (e.g. drive module 100 may be slid onto an axle and
secured thereon with a releasable clamping mechanism). Consequently, if a drive module
requires maintenance, repair, or replacement, the drive module can be easily removed
and fixed by an end-user. Additionally, although not shown in FIGs. 4A-C, connecting
a drive module of the present invention to an autonomous vehicle may also involve
electronically or electromagnetically coupling the drive module to the autonomous
vehicle.
[0036] In the particular embodiment depicted in FIGs. 4A-C, a drive module 200 is coupled
to a main body 22 of the pool cleaner 20 by engaging the drive module 200 with couplers
32 and an opening 34 included on a side 30 of the main body 22. In order to engage
the couplers 32, the drive module 200 includes clasps 252 configured to slide vertically
into slots created by the couplers 32. In this particular embodiment, each drive module
200 includes four clasps 252, arranged in two pairs (to match the arrangement of couplers
32 included on the main body 22 of the pool cleaner 20); but in other embodiments
any desirable arrangement may be utilized.
[0037] Once the clasps 252 have been inserted into the couplers 32, as is illustrated in
Figs. 4A and 4C (with FIG. 4A illustrating a portion of the main body 22 upside down
and not properly aligned with the drive module 200, for illustrative purposes), the
drive module 200 may be pressed against the main body to engage a detent 254 with
the opening 34 and create a snap engagement between the drive module 200 and the main
body 22. Thus, the clasps 252 and couplers 32 may secure the drive module 200 to the
main body 22 with respect to two directions (e.g., the x-direction and the z-direction)
and the detent 254 and opening 34 may secure the drive module 200 to the main body
22 with respect to a third direction (e.g., vertically, or with respect to the y-axis).
Since the detent 254 only resists a certain amount of force, the drive modules 200
may be detached from the main body 22 by pulling the drive module 200 laterally away
from the main body 22 with a sufficient force to disengage the detent 254 from the
opening 34. Then, the drive module 200 may be slid downwards (or upwards if the pool
cleaner 20 is upside down) by the end-user to remove the clasps 252 from the couplers
32 and rapidly decouple the drive module 200 from the main body 22 (without tools).
[0038] In the particular embodiment depicted in FIGs. 4A-C, one drive module 200 is shown
being installed onto a first side 30 of a main body 22 of the pool cleaner 20, but
it is to be understood that a second drive module 200 may be installed on a second
side of the main body 22 in a similar manner. In fact, in some embodiments, the drive
module may be symmetrical so that the drive module 200 can be installed on either
side of an autonomous vehicle, such as pool cleaner 20. For example, in the depicted
embodiment, the detent 254 may be substantially centered on the drive module 200 and
features included on the drive assembly 400 may be mirrored about the detent 254.
[0039] That being said, in other embodiments, the detent 254 could be provided on the main
body 22 and an opening equivalent to openings 34 could be included on the drive module
200. Similarly, in other embodiments, the clasps 252 could be included on the main
body 22 and the drive module 200 could include openings/couplers configured to receive
the clasps. Still further, in other embodiments, the drive modules 200 may not include
any clasps or detents and may be coupled to any portion of an autonomous vehicle in
any manner that allows for rapid, removable coupling, so that an end-user can quickly
remove the drive module 200 from an autonomous vehicle without tools.
[0040] Now referring to FIGs. 5-7, the drive module 100 illustrated in FIG. 1 is shown in
further detail to explain another embodiment of the drive module presented herein.
In this particular embodiment, the drive module 100 includes a controller 180, such
as a printed circuit board (PCB), and motor 170 disposed within a housing 102. The
controller 180 may be substantially similar to the controller 280 and, thus, any description
of the controller 280 included above may also be applicable to controller 180. Thus,
generally, controller 180 is configured to cause the motor 170 to drive a propulsion
element 160 disposed externally of the housing 102.
[0041] In contrast with drive module 200, drive module 100 includes a propulsion element
160 that is a wheel 162 with a hub or rim (see FIG. 6) and the motor 170 is configured
to drive the wheel 162 and hub. Also in contrast with drive module 200, drive module
100 is configured to be electronically and/or operatively coupled to the autonomous
robot (e.g., robot 10) to which the drive module 100 is coupled. Consequently, as
shown best in FIG. 5, the drive module 100 includes a cable 182 out to the robot.
Controller 180 may receive instructions and power via cable 182 and may, in turn,
transmit power and instructions to the motor 170 via cable 175.
[0042] In this particular embodiment, the drive module 100 is configured specifically for
a submersible autonomous vehicle (e.g., a pool cleaner) and, thus, the controller
180 and motor 170 are sealed within the housing 102. In particular, the motor 170
and controller 180 are sealed between an enclosure top 166 and an enclosure base 140.
In the depicted embodiment, the enclosure base 140 and enclosure top 166 are sealed
together with a sealing ring 144 disposed therebetween. The enclosure base 140 and
enclosure top 166 include openings to allow a motor shaft and axle to pass therethrough
and these openings may be also be sealed, such as with sealing elements 142, 164,
and/or 184. For example, element 142 may be a motor shaft v-seal while elements 132
and 164 are seals with ball bearings configured to receive an axle (with wired connections
included therein) while epoxy seals 184 seal any exposed area in or around the axle
and bearings 134 and 164.
[0043] The shaft of motor 170 extends externally of the housing 102 formed by the enclosure
base 140 and enclosure top 166 and may engage and/or support a gear train that is
configured to drive the propulsion element 160. Specifically, the motor 170 drives
a motor gear 134 disposed outside of the housing 102 (e.g., on the opposite side of
the enclosure base 140 from the motor 170). The motor gear 134 drives a wheel gear
130 configured to drive the propulsion element 160 (including wheel 162) about the
motor 170 to create propulsion (thereby moving a pool cleaner to which the drive module
100 is coupled).
[0044] In some embodiments, the wheel gear 130 drives an axle (not shown), but in the depicted
embodiment, the axle is rotationally fixed and the propulsion element 160 is driven
about the fixed axle. Similarly, in some embodiments, the housing 102 (formed by enclosure
top 166 and enclosure base 140) rotates with or within the propulsion element, but
in the depicted embodiment, the housing 102 is fixed with respect to axle and propulsion
element 160, thereby limiting the forces imparted on the controller 180 and motor
170 and preserving the longevity of these components. In fact, in the particular embodiment
shown in the Figures, an axle clamp 120 fixes the housing 102 (including the motor
170 and controller 180) to a fixed axle and, thus, the housing 102 remains stationary
while the propulsion element 160 rotates therearound. That being said, different axle
configurations allow different drive configurations. For example, in at least some
embodiments, a single motor can be used to drive multiple wheels disposed on the same
axle. To facilitate some of these embodiments, the drive module 100 may be electrically
coupled to a host robot via a swiveling electrical connection (e.g., when the entire
drive module 100 rotates around an axle).
[0045] FIG. 8 depicts a high level diagram of operations performed by a drive module (in
accordance with the present invention) when the drive module is coupled to an autonomous
vehicle. Initially, at step 802, a determination may be made (e.g., by the controller
of the drive module) as to whether the drive module is in communication with a control
system of a host autonomous vehicle, insofar as "host" simply denotes the autonomous
vehicle to which the drive module is coupled. If the drive module is in communication
with a control system of the host autonomous vehicle, the drive module may receive
or retrieve drive instructions from the control system (e.g., the on-board computer)
of the host autonomous vehicle and designate these instructions as the current drive
instructions at step 804. As an example, when drive module 100 is coupled to an autonomous
vehicle, a wired connection may be established between drive module 100 and the host
autonomous vehicle and the drive module may retrieve or receive drive instructions.
[0046] By comparison, when the drive module 200 is coupled to an autonomous vehicle, the
drive module 200 may not necessarily be in communication with control systems of the
host autonomous vehicle (e.g., if a wireless connection cannot be established with
the host autonomous vehicle). In instances where the drive module is not communicating
with a control system of a host autonomous vehicle, the drive module may retrieve
internal drive instructions (e.g., from memory) and designate the retrieved drive
instructions as the current drive instructions at step 806.
[0047] At step 810, a determination is made (e.g., by the controller) as to whether the
drive module is in communication with another drive module. If the drive module is
not in communication with another drive module, the drive module may drive the propulsion
element, at step 814, in accordance with the current drive instructions from step
804 or 806 (e.g., the controller may drive the motor in a certain speed or in a certain
direction, thereby creating specific propulsion, via the propulsion element). Alternatively,
if the drive module is in communication with a second drive module, the current drive
instructions may be adjusted based on the communication, at step 812. For example,
if an autonomous robot includes a first drive module disposed on the right side of
the robot and a second drive module disposed on the left side of the robot, the two
drive modules may communicate to coordinate movements and facilitate various driving
patterns (e.g., in a master-slave configuration). Once the current drive instructions
are adjusted (e.g., the drive module determines if it is a master or slave and responds
appropriately), the propulsion element(s) may be driven accordingly at step 814. Then,
the drive module may continue to check for further instructions by monitoring for
new connections.
[0048] Now turning to FIG. 9, in at least some embodiments, the drive module presented herein
may provide propulsion elements on both sides of an autonomous, submersible vehicle.
For example, the drive module may provide both front wheels, both back wheels, all
four wheels, or any combination of wheels on both sides of the autonomous pool cleaner
10 depicted in FIG. 1. Alternatively, the drive module may provide both endless tracks
included in the autonomous pool cleaner 20 depicted in FIG. 2. Still further, in some
embodiments, the drive module may add additional propulsion elements to a pool cleaner
(e.g., the drive module may add fifth and sixth wheels to the autonomous pool cleaner
10 depicted in FIG. 1). The drive module 900 depicted in FIG. 9 depicts one example
drive module that provides propulsion elements on both sides of an autonomous, submersible
vehicle.
[0049] In order to provide propulsion elements (e.g., wheels) on both sides of a host autonomous,
submersible vehicle on which the drive module 900 is installed, the drive module 900
includes a housing 902 that extends from a first end 902a to a second end 902b. The
first end 902a is configured to align with or extend beyond a first side of the host
autonomous vehicle and the second end 902b is configured to align with or extend beyond
a second side (opposite the first side) of the host autonomous vehicle. That is, the
housing 902 spans the width of its host autonomous vehicle. As a more specific example,
in some embodiments, the housing is cylindrical, and has a width dimension which approximates
the width of the host autonomous submersible vehicle to which it is attached (e.g.,
the housing 902 may resemble the front of the autonomous submersible vehicle 10 depicted
in FIG. 1). As another example, the housing 902 may be s substantially flat or slim
plate that extends beneath a chassis (and spans the width of the chassis) of a host
autonomous submersible, i.e., to provide endless tracks on either side of the chassis.
[0050] In the embodiment depicted in FIG. 9, a first propulsion element 903 is included
on, attached to or otherwise coupled to the first end 902a of the housing 902 and
a second propulsion element 904 is included on, attached to or otherwise coupled to
the second end 902b of the housing 902. For example, the propulsion elements 903,
904 may be wheels attached to axles that extend through water impermeable seals included
on the ends 902a, 902b of the housing 900. That being said, in some embodiments, at
least one of the propulsion elements 903, 904 is free-wheeling (i.e., not driven)
and need not extend through the housing 902. Instead, a free-wheeling propulsion element
may be coupled to an exterior surface of the housing 902 without extending therethrough.
[0051] Moreover, and regardless of the shape of the housing 902, the housing 902 may be
rapidly, releasably coupled to an autonomous robot (coupled without tools) with any
desirable releasable couplings/attachments so that propulsion elements 903 and 904
are rapidly releasably coupleable to an autonomous robot. For example, the housing
902 may be coupled to a chassis of an autonomous, submersible vehicle with detents,
clasps, and/or slots, similar to the rapid releasable attachment discussed in detail
above in connection with FIGs. 4A-C, The housing 902 may be coupled to a front, back,
bottom, or any other location of an autonomous, submersible vehicle.
[0052] The housing 902 also provides a waterproof compartment for a number of electrical
or mechanical components, including a power source 906, a controller 910, a first
motor 912, and a second motor 914, as well as any other components included in the
drive module 900 (for example, the drive module 900 may also include memory and/or
a communications module, similar to the memory 282 and communications module 292 depicted
in FIG. 3 and described above). That is, the housing 902 defines a watertight or water
impermeable internal compartment/receptacle that can receive or house any number of
electrical or mechanical components.
[0053] Generally, the power source 906 and controller 910 are similar to the power source
294 and controller 280 depicted in FIG. 3. Consequently, the descriptions of power
source 294 and controller 280 included herein are to be understood to apply to power
source 906 and controller 910. However, now, the controller 910 is operable to control
both motor 912 and motor 914. Meanwhile, the power source 906 may be a battery or
other such power source that is configured to supply power to the controller 910 and
any other components included in the drive module (e.g., motors 912 and 914) without
receiving any continuous external power.
[0054] As was alluded to above (i.e. when describing power source/interface 294), in some
embodiments, the power source 906 may intermittently receive power from an external
power source. For example, the power source 906 may be charged from time to time.
In FIG. 9, the power source is operably coupled to a waterproof interface 908 to facilitate
charging. The waterproof interface 908 is disposed on the periphery of the housing
902 and configured to connect the power source 906 to an external power source for
charging/recharging. Alternatively, a non-contact power transfer circuit, such as
an inductive charging system, may be incorporated in the housing 902 to facilitate
an electrical connection between the power source 906 and an external power source.
[0055] Still referring to FIG. 9, the first motor 912 may also be similar to the motor 270
depicted in FIG. 3 and, thus, any description of motor 270 may apply to first motor
912(which may also be referred to as a first propulsion motor 912), insofar as first
motor 912 may be configured to drive propulsion element 904 in the same manner that
motor 270 is configured to drive propulsion element 260. On the other hand, the second
motor 914 may only drive a propulsion element (e.g., propulsion element 903) in some
embodiments and, thus, the description of motor 270 may only apply to the second motor
914 in some embodiments.
[0056] More specifically, in some embodiments the second motor 914 may be oriented such
that a shaft 916 of the motor 914 extends in an opposite direction as compared to
a shaft 913 of the first motor 912. The shaft 916 may also be parallel to or in line
with shaft 913. In these embodiments, the second motor 914 may drive the first propulsion
element 903 in the same manner that motor 270 drive a propulsion element 260 (as is
described repeatedly herein). That is, the second motor 914 may be arranged so that
the second motor 914 can drive the first propulsion element 903 based on instructions
from the controller 910.
[0057] However, in other embodiments, such as the embodiment depicted in FIG. 9, the second
motor 914 is configured to drive one or more internal systems or components included
in the host autonomous vehicle (i.e., based on instructions from the controller 910).
More specifically, the second motor 914 may be oriented such that shaft 916 is perpendicular
to the shaft 913 (or rotational axis) of the first motor 912. That is, the second
motor 914 may be positioned in the housing 902 so that the shaft 916 of the second
motor 914 extends in a direction which is parallel to a longitudinal dimension (front-to-back
dimension) of the submersible vehicle. The shaft 916 may exit the housing 902 via
a water impermeable seal and, thus, may be suitable for transferring rotational energy
from the drive module 900 to one or more internal systems of the host autonomous vehicle,
such as a pump system of the autonomous vehicle.
[0058] More specifically, a distal end of shaft 916 (i.e., an end of the shaft 916 disposed
outside the housing 902) may include a mechanical coupler 917 that may be configured
to engage and drive an internal mechanical system of the host autonomous vehicle.
The coupler 917 may be a mechanical clutch (like a dog clutch), a toothed wheel or
gear, or any other mechanical coupler now known or developed hereafter. As one additional
example, the coupler 917 may comprise specific shaping at the end of the shaft 916
that forms a key or mating surface, such as a D-shape. Regardless of its shape or
configuration, the coupler 917 may connect, either directly or via a linkage (e.g.,
a gear train), to any internal system (and, more specifically, any mechanical system)
of the host autonomous vehicle. In at least some of these embodiments, the drive module
900 remains electrically isolated from the autonomous vehicle (i.e., the connection
provided by coupler 917 is purely mechanical) when coupled to an internal system of
the host autonomous vehicle via coupler 917.
[0059] As a specific example, in some embodiments the coupler 917 may engage a gear train
configured to drive a pump impeller. Consequently, once the drive module 900 is coupled
to the host autonomous submersible vehicle and the second motor 914 drives shaft 916,
the coupler 917 may causes the impeller to rotate (i.e., the motor 914 may drive the
impeller) and create suction for drawing fluid and debris through the host autonomous,
submersible vehicle for filtering. The fluid jet created by the impeller may also
be employed to provide a fluid jet force for propulsion of the submersible vehicle.
[0060] Due to the foregoing features, drive module 900 may provide a single integrated unit
(comprising a first motor (a drive motor), a propulsion element, a second motor (an
impeller motor), and a power source), which may be removed from the autonomous, submersible
vehicle as a single unit for maintenance, replacement, upgrades, and/or recharging.
In fact, in some instances, when an autonomous, submersible vehicle needs maintenance,
replacement, upgrades, and/or recharging, a majority of the autonomous, submersible
vehicle may be left in a pool and only the drive module 900 may need to be removed
from the pool In other words, drive module 900 may provide a compact operational hub
for an autonomous vehicle that may be easier to transport, examine, etc. and, thus,
may easier to repair, upgrade, service, etc. (at least as compared to pool cleaners
that cannot be easily disassembled by an end user prior to maintenance or upgrade
operations).
[0061] Still referring to FIG, 9, as mentioned, in some embodiments, the drive module 900
may include a communications module configured to establish at least one of a wired
or wireless connection with the host submersible autonomous vehicle on which the drive
module 900 is installed. In these embodiments, the controller 910 may be configured
to communicate, via the communications module, with a control system for the submersible
autonomous vehicle to retrieve drive instructions for the controller 910. For example,
the controller 910 may operate in accordance with the operations described in connection
with FIG. 8. In fact, in some embodiments, the drive module 900 may communicate with
another drive module as is explained in connection with FIG. 8. For example, a first
drive module 900 may be installed as front wheels of an autonomous vehicle, a second
drive module 900 may be installed as back wheels of the autonomous vehicle and the
two drive modules may communicate to drive the autonomous vehicle. In at least some
embodiments all of these communications are wireless communications so that each drive
module 900 is electrically isolated from other drive modules and the autonomous vehicle.
[0062] Similarly, in some embodiments, the controller 910 may be configured to communicate,
via the communications module, with a control system for the submersible autonomous
vehicle to retrieve internal system instructions for the controller 910. For example,
the controller 910 may obtain cleaning instructions that indicate how to control a
pump system in order to attempt to collect debris. Alternatively, the drive module
may store internal system instructions, such as cleaning instructions, in memory included
therein.
[0063] To summarize, in one form, a drive module for autonomous vehicles includes a propulsion
element configured to engage and rotate against a surface, a motor configured to drive
the propulsion element, and a controller configured to cause the motor to drive the
propulsion element. The drive module also includes a housing configured to be removably,
releasably coupled to an autonomous vehicle. The motor and the controller are disposed
within the housing.
[0064] While the invention has been illustrated and described in detail and with reference
to specific embodiments thereof, it is nevertheless not intended to be limited to
the details shown, since it will be apparent that various modifications and structural
changes may be made therein without departing from the scope of the inventions and
within the scope and range of equivalents of the claims. In addition, various features
from one of the embodiments may be incorporated into another of the embodiments. Accordingly,
it is appropriate that the appended claims be construed broadly and in a manner consistent
with the scope of the disclosure as set forth in the following claims.
[0065] It is also to be understood that the drive module described herein, or portions thereof
may be fabricated from any suitable material or combination of materials, such as
plastic, foamed plastic, wood, cardboard, pressed paper, metal, supple natural or
synthetic materials including, but not limited to, cotton, elastomers, polyester,
plastic, rubber, derivatives thereof, and combinations thereof. Suitable plastics
may include high-density polyethylene (HDPE), low-density polyethylene (LDPE), polystyrene,
acrylonitrile butadiene styrene (ABS), polycarbonate, polyethylene terephthalate (PET),
polypropylene, ethylenevinyl acetate (EVA), or the like. Suitable foamed plastics
may include expanded or extruded polystyrene, expanded or extruded polypropylene,
EVA foam, derivatives thereof, and combinations thereof.
[0066] Finally, it is intended that the present invention cover the modifications and variations
of this invention that come within the scope of the appended claims and their equivalents.
For example, it is to be understood that terms such as "left," "right," "top," "bottom,"
"front," "rear," "side," "height," "length," "width," "upper," "lower," "interior,"
"exterior," "inner," "outer" and the like as may be used herein, merely describe points
of reference and do not limit the present invention to any particular orientation
or configuration. Further, the term "exemplary" is used herein to describe an example
or illustration. Any embodiment described herein as exemplary is not to be construed
as a preferred or advantageous embodiment, but rather as one example or illustration
of a possible embodiment of the invention.
[0067] Similarly, when used herein, the term "comprises" and its derivations (such as "comprising",
etc.) should not be understood in an excluding sense, that is, these terms should
not be interpreted as excluding the possibility that what is described and defined
may include further elements, steps, etc. Meanwhile, when used herein, the term "approximately"
and terms of its family (such as "approximate", etc.) should be understood as indicating
values very near to those which accompany the aforementioned term. That is to say,
a deviation within reasonable limits from an exact value should be accepted, because
a skilled person in the art will understand that such a deviation from the values
indicated is inevitable due to measurement inaccuracies, etc. The same applies to
the terms "about" and "around" and "substantially".
1. A self-contained drive module (900) for attachment to a submersible autonomous vehicle
(10, 20), the drive module comprising:
a propulsion element (904) configured to engage and rotate against a surface;
a first motor (912) configured to drive the propulsion element (904);
a second motor (914) configured to drive an internal system of the submersible autonomous
vehicle (10, 20);
a controller (910) configured to cause the first motor (912) to drive the propulsion
element (904) and the second motor (914) to drive the internal system; and
a housing (902) configured to be removably coupled to the exterior of the submersible
autonomous vehicle (10, 20), wherein the first motor (912), the second motor (914),
and the controller (910) are disposed substantially within the housing (902).
2. The self-contained drive module (900) of claim 1, wherein the self-contained drive
module (900) is electrically isolated from electrical components within the submersible
autonomous vehicle (10, 20) and the self-contained drive module (900) further comprises:
a power source (906) configured to supply power to the controller (910), the first
motor (912), and the second motor (914).
3. The self-contained drive module (900) of claim 2, further comprising:
a waterproof interface (908) that can be coupled to an external power source to charge
the power source (906).
4. The self-contained drive module (900) of any of the preceding claims, further comprising:
a communications module (292) configured to establish a wireless connection with a
control system within the submersible autonomous vehicle (10, 20), wherein the controller
(910) is configured to communicate, via the communications module (292), with the
control system within the submersible autonomous vehicle (10, 20) to retrieve drive
instructions or internal system instructions for the controller (910).
5. The self-contained drive module (900) of any of the preceding claims, wherein the
propulsion element (904) comprises at least one of a wheel and an endless tread.
6. The self-contained drive module (900) of any of the preceding claims, wherein the
self-contained drive module (900) is operatively isolated from control systems within
the submersible autonomous vehicle (10, 20).
7. The self-contained drive module (900) of claim 7, wherein the controller (910) comprises:
a memory (282) storing drive instructions and internal system instructions; and
at least one processor (284) configured to:
control the motor in accordance with the drive instructions; and
control the internal system based on the internal system instructions.
8. The self-contained drive module (900) of any of the preceding claims, wherein the
internal system is a pump system.
9. The self-contained drive module (900) of any of the preceding claims, wherein the
submersible autonomous vehicle (10, 20) comprises a pool cleaner including a fluid
propulsion drive system.
10. A submersible autonomous pool cleaner (10, 20) comprising:
a main body including an exterior surface with a first side and a second side; and
a drive module (900) that is releasably coupled to the exterior surface of main body,
wherein the drive module (900) extends from the first side to the second side when
coupled to the main body and includes a propulsion element (904), a motor (912) configured
to drive the propulsion element (904), and a controller (910) configured to cause
the motor (912) to drive the propulsion element (904).
11. The submersible autonomous pool cleaner (10, 20) of claim 10, wherein the propulsion
element (904) is a first propulsion element disposed on the first side of the exterior
surface and the drive module (900) further comprises:
a second propulsion element (903) disposed on the second side of the exterior surface.
12. The submersible autonomous pool cleaner (10, 20) of claim 10 or 11, wherein the motor
(912) is a first motor and the drive module (900) further comprises:
a second motor (914) configured to drive an internal system of the submersible autonomous
pool cleaner or the second propulsion element (903).
13. The submersible autonomous pool cleaner (10, 20) of claim 12, wherein the first motor
(912), the second motor (914), and the controller (910) are sealed within a watertight
portion of a housing (902) of the drive module (900) and a motor shaft (916) extends
out of a sealed opening in the watertight portion of the drive module housing (902)
to connect the second motor (914) to the internal system or the second propulsion
element (903).
14. The submersible autonomous pool cleaner (10, 20) of claim 13, wherein the motor shaft
(916) is a first motor shaft, the sealed opening is a first sealed opening, and a
second motor shaft (913) extends out of a second sealed opening in the watertight
portion of the drive module housing (902) to connect the first motor (912) to the
propulsion element (904).
15. The submersible autonomous pool cleaner (10, 20) of claim 14, wherein the first motor
shaft (916) is perpendicular to the second motor shaft (913).