Technical Field
[0001] The present disclosure generally relates to an electric tool system. More particularly,
the present disclosure relates to an electric tool system including a portable tool
body.
Background Art
[0002] Patent Literature 1 discloses an operations management system. The operations management
system includes a controller and a tool.
[0003] The tool is used to perform operations of fastening a fastening member. The tool
transmits data about fastening torque to the controller. The controller includes a
processing unit. The processing unit performs decision processing of determining,
based on the fastening torque applied by the tool to the fastening member and a captured
image generated by an image capture device, whether the operations have been performed
normally. When a decision is made that the operations have been performed normally,
the processing unit determines that the operations have been done at the current target
spot and performs the processing of transmitting an instruction signal about the next
target spot. On the other hand, when a decision is made that the operations have been
performed abnormally, the processing unit performs the processing of transmitting
a signal instructing that the operations be performed properly.
Citation List
Patent Literature
Summary of Invention
[0005] An electric tool system such as the operations management system disclosed in Patent
Literature 1 is sometimes required to perform operations using a tool with improve
efficiency.
[0006] An object of the present disclosure is to improve the efficiency of operations.
[0007] An electric tool system according to an aspect of the present disclosure includes
a driving unit, an operating member, a driving controller, a tool body, a detection
unit, a storage unit, and a parameter calculator. The driving unit includes a motor
and drives a tip tool in rotation by running the motor and thereby has operations
done on a work target. The operating member is operated by a user. The driving controller
controls operation of the driving unit in accordance with an operating command entered
by the user via the operating member. The tool body is a portable tool body for holding
the driving unit, the operating member, and the driving controller. The detection
unit detects a physical quantity representing a spatial relationship of at least one
of the tip tool or the tool body with respect to the work target. The storage unit
stores correspondence which associates a control parameter related to the operation
of the driving unit with the physical quantity. The parameter calculator calculates,
based on a detection value of the physical quantity that has been detected by the
detection unit and by reference to the correspondence, an optimum value of the control
parameter in a state where the operating member is being operated. The driving controller
controls the operation of the driving unit based on the optimum value of the control
parameter calculated by the parameter calculator.
Brief Description of Drawings
[0008]
FIG. 1 is a block diagram of an electric tool system according to an exemplary embodiment;
FIG. 2 illustrates a system configuration for the electric tool system;
FIG. 3 is a schematic representation of an electric tool for use in the electric tool
system;
FIG. 4 is a graph showing how the electric tool system operates; and
FIG. 5 is a flowchart showing the procedure of operation of the electric tool system.
Description of Embodiments
[0009] An electric tool system according to an embodiment of the present disclosure will
be described with reference to the accompanying drawings. The drawings to be referred
to in the following description of embodiments are all schematic representations.
Thus, the ratio of the dimensions (including thicknesses) of respective constituent
elements illustrated on the drawings does not always reflect their actual dimensional
ratio.
(1) Overview
[0010] As shown in FIG. 1, an electric tool system 100 according to this embodiment includes
an electric tool 1.
[0011] As shown in FIGS. 1-3, the electric tool 1 includes a driving unit 13, an operating
member 12, a driving controller 111, and a tool body 10. The electric tool 1 further
includes a detection unit 15, a storage unit 17, and a parameter calculator 112.
[0012] The driving unit 13 includes a motor 131. The driving unit 13 drives a tip tool 20
(refer to FIG. 3) in rotation by running the motor 131 to have operations done on
a work target W1. The work target W1 may include an object having an arbitrary shape
and made of an arbitrary material such as metal, wood, or resin. In the example illustrated
in FIG. 3, the work target W1 is a wall, through which a screw hole H1 is opened.
The operations to be performed on the work target W1 may be, for example, the operations
of fastening a fastening member 200 into the screw hole H1 of the work target W1.
The fastening member 200 may be a screw or a bolt, for example.
[0013] The operating member 12 is operated by a user (operator). The driving controller
111 controls the operation of the driving unit 13 in accordance with an operating
command entered by the user via the operating member 12.
[0014] The tool body 10 is a portable tool body. The tool body 10 holds the driving unit
13, the operating member 12, and the driving controller 111. In the electric tool
system 100 according to this embodiment, the tool body 10 further holds the detection
unit 15, the storage unit 17, and the parameter calculator 112.
[0015] The detection unit 15 detects a physical quantity representing a spatial relationship
of at least one of the tip tool 20 or the tool body 10 with respect to the work target
W1. The storage unit 17 stores correspondence which associates a control parameter
related to the operation of the driving unit 13 with the physical quantity. The parameter
calculator 112 calculates, based on a detection value of the physical quantity that
has been detected by the detection unit 15 and by reference to the correspondence
stored in the storage unit 17, an optimum value of the control parameter related to
the operation of the driving unit 13 in a state where the operating member 12 is being
operated. The driving controller 111 controls the operation of the driving unit 13
based on the optimum value of the control parameter calculated by the parameter calculator
112.
[0016] In the electric tool system 100 according to this embodiment, the control parameter
may include, for example, a maximum number of revolutions as an upper limit of the
number of revolutions of the motor 131. The parameter calculator 112 calculates an
optimum value of the maximum number of revolutions as the optimum value of the control
parameter. The driving controller 111 controls the operation of the driving unit 13
based on the optimum value of the maximum number of revolutions calculated by the
parameter calculator 112.
[0017] In this case, if the spatial relationship of the tip tool 20 and/or the tool body
10 with respect to the work target W1 were significantly different from the intended
one while operations are being performed on the work target W1 using the electric
tool 1, then the operations could not be performed properly. For example, in a situation
where the operations of fastening the fastening member 200 into the screw hole H1
of the work target W1 are performed, for example, if the tool body 10 were tilted
with respect to the work target W1 more significantly than expected, then chances
of causing inconveniences such as so-called "galling" would increase. If the operations
on the work target W1 failed to be performed properly, then the work target W1 would
turn into a defective product, or the operations would need to be redone all over
again. This would cause a decrease in the efficiency of operations.
[0018] In contrast, in the electric tool system 100 according to this embodiment, in a state
where the operating member 12 is being operated, the driving unit 13 is controlled
with the spatial relationship of the tip tool 20 and/or the tool body 10 with respect
to the work target W1 taken into account. This may reduce the chances of failing to
perform the operations on the work target W1 properly, thus contributing to improving
the efficiency of operations.
(2) Details
[0019] Next, an electric tool system 100 according to this embodiment will be described
in detail with reference to the accompanying drawings. The electric tool system 100
includes not only the electric tool 1 but also a processor 9 as well.
(2.1) Processor
[0020] The processor 9 may be implemented as, for example, a data processor having the ability
to perform appropriate arithmetic processing.
[0021] The processor 9 may have any form without limitation. The processor 9 may be any
device having the ability to communicate with the electric tool 1 either directly
or indirectly and to perform desired processing in accordance with a predetermined
program. The processor 9 may be, for example, a wearable terminal in the shape of,
for example, a pair of eyeglasses or a bracelet to be worn by the user. Alternatively,
the processor 9 may also be a mobile telecommunications device such as a smartphone
or a tablet computer. Still alternatively, the processor 9 may also be a stationary
data processor such as a laptop computer or a desktop computer.
[0022] As shown in FIG. 1, the processor 9 includes a communications unit 91, a control
unit 92, an operating member 93, and a display unit 94.
[0023] The communications unit 91 is a communications module for use to establish communication
with the electric tool 1 (specifically, with a communications unit 16 thereof (to
be described later)). The communications unit 91 may establish, for example, a short-range
wireless communication compliant with the ZigBee (R) standard.
[0024] The display unit 94 includes a thin display such as a liquid crystal display or an
organic electroluminescent (EL) display and has its content of display controlled
by the control unit 92.
[0025] The operating member 93 may include, for example, a touchscreen switch provided for
the thin display serving as the display unit 94 and outputs a signal indicating the
operating command entered to the control unit 92. The operating member 93 may include,
for example, a button switch, a mouse, a keyboard, or any other input device.
[0026] The control unit 92 controls the operations of the communications unit 91, the operating
member 93, the display unit 94, and other components. The control unit 92 is implemented
as a computer system including one or more processors and a memory. The computer system
performs the functions of the control unit 92 by making the one or more processors
execute a program stored in the memory. In this embodiment, the program is stored
in advance in the memory of the control unit 92. Alternatively, the program may also
be downloaded via a telecommunications line such as the Internet or distributed after
having been stored in a non-transitory storage medium such as a memory card.
[0027] As shown in FIG. 1, the control unit 92 includes a tool information acceptor 921.
The tool information acceptor 921 accepts information (tool information) about the
tip tool 20 attached to a tip tool attachment 134 (to be described later) of the tool
body 10. The tool information acceptor 921 accepts the tool information by accepting
the entry from the user via the operating member 93 in a state where a predetermined
input screen image is displayed on the display unit 94, for example.
[0028] The tool information may include information about the length of the tip tool 20.
The tool information may also include information about the diameter of the tip tool
20 and its type (such as whether the tip tool 20 is a screwdriver bit or a socket
bit). The tool information may further include product information (such as the name
of the manufacturer and the model number) of the tip tool 20.
[0029] The control unit 92 transmits the tool information thus accepted to the electric
tool 1 via the communications unit 91.
(2.2) Electric tool
[0030] The electric tool 1 may be an electric tool for use by business operators at factories
and construction sites, for example. The electric tool 1 may be used, for example,
to perform the operations of fastening a plurality of fastening members 200 onto the
work target W1 in accordance with a blueprint or operating instructions, for example.
The electric tool 1 of this type may be, for example, an electric impact screwdriver
for fastening a fastening member 200 by turning the fastening member 200 with impacting
force applied thereto. Note that the electric tool 1 does not have to be an electric
impact screwdriver but may also be an electric impact wrench or an electric drill-screwdriver
or an electric torque wrench that does not require applying impacting force.
[0031] As shown in FIGS. 1-3, the electric tool 1 includes the tool body 10, the control
unit 11, the operating member 12, the driving unit 13, a sensor unit 14, the detection
unit 15, the communications unit 16, the storage unit 17, and a power supply unit
18.
[0032] The tool body 10 holds the control unit 11, the operating member 12, the driving
unit 13, the sensor unit 14, the detection unit 15, the communications unit 16, the
storage unit 17, and the power supply unit 18.
[0033] As shown in FIG. 3, the tool body 10 includes a cylindrical barrel 101 and a grip
102 protruding radially from a circumferential surface of the barrel 101.
[0034] An output shaft 133 of the driving unit 13 protrudes from one axial end portion of
the barrel 101. The tip tool attachment 134 is provided at the tip of the output shaft
133. The tip tool attachment 134 may include, for example, a chuck. A tip tool 20
(such as a screwdriver bit or a socket bit) selected according to the work target
W1 and the fastening member 200 is attached removably to the tip tool attachment 134.
[0035] To (the lower end in FIG. 3 of) the grip 102, a battery pack 103, which houses the
power supply unit 18 in a resin case, is attached removably.
[0036] The power supply unit 18 includes a storage battery. The power supply unit 18 is
housed in the battery pack 103. The battery pack 103 is formed by housing the power
supply unit 18 in a resin case. The storage battery of the power supply unit 18 may
be charged by removing the battery pack 103 from the tool body 10 and connecting the
battery pack 103 thus removed to a charger. The power supply unit 18 supplies, using
the electricity stored in the storage battery, power required to allow an electric
circuit including the control unit 11 and the (motor 131 of the) driving unit 13 to
operate. The power supply unit 18 and the battery pack 103 are supposed to be constituent
elements of the electric tool 1 in this embodiment but may also be counted out of
the constituent elements of the electric tool 1.
[0037] The control unit 11 controls the operations of the driving unit 13, the sensor unit
14, the detection unit 15, the communications unit 16, and other components. The control
unit 11 may be implemented as a computer system including one or more processors and
a memory. That is to say, the computer system performs the functions of the control
unit 11 by making the one or more processors execute a program stored in the memory.
In this embodiment, the program is stored in advance in the memory of the control
unit 11. Alternatively, the program may also be downloaded via a telecommunications
line such as the Internet or distributed after having been stored in a non-transitory
storage medium such as a memory card. The control unit 11 may be implemented as, for
example, a field-programmable gate array (FPGA) or an application specific integrated
circuit (ASIC). The computer system (such as a circuit board 110) functioning as the
control unit 11 may be housed, for example, inside the grip 102.
[0038] As shown in FIG. 1, the control unit 11 includes the driving controller 111. The
driving controller 111 controls the operation of the (motor 131 of the) driving unit
13 in accordance with an operating command entered by the user via the operating member
12.
[0039] The operating member 12 includes a trigger switch 121 provided for the grip 102.
Having the trigger switch 121 operated by the user causes an operating signal, of
which the magnitude is proportional to the depth to which the trigger switch 121 has
been pulled (i.e., manipulative variable), to be output to the driving controller
111. The driving controller 111 adjusts the number of revolutions of the motor 131
of the driving unit 13 to make the motor 131 run at a velocity in accordance with
the operating signal supplied from the operating member 12. As used herein, the "number
of revolutions of the motor 131" refers to the rotational velocity of the motor 131
and means the number of times (or velocity) [rpm] the rotor of the motor 131 rotates
per unit time.
[0040] The driving unit 13 includes the motor 131, an impact mechanism 132, the output shaft
133, and the tip tool attachment 134.
[0041] The operation (rotation) of the motor 131 is controlled by the driving controller
111. The rotational force of the output shaft of the motor 131 is transmitted to the
output shaft 133 via the impact mechanism 132. The impact mechanism 132 is configured
to reduce the rotational velocity of the output shaft of the motor 131 and transmit
the rotational force with the rotational velocity thus reduced to the output shaft
133 when finding the output torque equal to or less than a predetermined level. The
impact mechanism 132 is configured to, when finding the output torque greater than
the predetermined level, rotate the output shaft 133 while applying impacting force
to the output shaft 133. The motor 131 and the impact mechanism 132 are housed in
the barrel 101.
[0042] The sensor unit 14 measures the fastening torque applied by the output shaft 133.
The sensor unit 14 may include, for example, a magnetostrictive torque sensor 141
attached to the output shaft 133. The magnetostrictive torque sensor 141 makes a coil,
which is installed at a non-rotating part thereof, detect a change in magnetic permeability
representing a strain caused due to application of the torque to the output shaft
133 and outputs a voltage signal proportional to the strain. In this manner, the sensor
unit 14 measures the torque applied to the output shaft 133. That is to say, the sensor
unit 14 measures the torque (fastening torque) applied by the electric tool 1 to the
fastening member 200. The sensor unit 14 outputs the torque thus measured (fastening
torque) to the control unit 11. Alternatively, the sensor unit 14 may measure the
torque applied to the output shaft of the motor 131. In that case, the sensor unit
14 may measure the fastening torque applied to the output shaft 133 based on, for
example, the measured value of the torque applied to the output shaft of the motor
131 and the reduction ratio of the speed reducer mechanism. Note that the sensor unit
14 does not have to include the magnetostrictive torque sensor 141. Rather, a specific
means for performing the functions of the sensor unit 14 may be changed as appropriate.
For example, the sensor unit 14 may measure the torque applied to the output shaft
of the motor 131 by detecting a current flowing through the motor 131. Alternatively,
the sensor unit 14 may make a vibration sensor count the number of times the impact
mechanism 132 has applied impacting force to the output shaft 133 and obtain the fastening
torque based on the number of times the impacting force has been applied.
[0043] The driving controller 111 drives the motor 131 in accordance with an operating signal
supplied from the operating member 12. The driving controller 111 includes an inverter
circuit for transforming the voltage supplied from the power supply unit 18 into a
drive voltage for the motor 131. The drive voltage may be, for example, three-phase
AC voltages including a U-phase voltage, a V-phase voltage, and a W-phase voltage.
The inverter circuit may be implemented as, for example, a combination of a PWM inverter
and a PWM converter. The PWM converter generates a PWM signal which has been pulse-width
modulated in accordance with a target value of the drive voltage (i.e., a voltage
command value). The PWM inverter applies a drive voltage corresponding to the PWM
signal to the motor 131, thereby driving the motor 131. The PWM inverter may include,
for example, half-bridge circuits for three phases and a driver. In the PWM inverter,
the driver turns ON and OFF switching elements in the respective half-bridge circuits
in accordance with the PWM signal, thereby applying a drive voltage corresponding
to the voltage command value to the motor 131.
[0044] In this case, the driving controller 111 controls the operation of the driving unit
13 to prevent the number of revolutions of the motor 131 from exceeding the maximum
number of revolutions. That is to say, the driving controller 111 controls the operation
of the driving unit 13 to prevent the number of revolutions of the motor 131 from
exceeding the maximum number of revolutions even if the trigger switch 121 has been
pulled to a maximum detectible depth. As used herein, the maximum number of revolutions
of the motor 131 refers to a preset upper limit value of the number of revolutions
of the motor 131.
[0045] The driving controller 111 has the function of stopping running the motor 131 of
the driving unit 13 when the value of the fastening torque measured by the sensor
unit 14 reaches the preset torque value, for example. Note that the preset torque
value is changeable. For example, the preset torque value may be changed by the control
unit 11 in accordance with a setting signal transmitted from the processor 9 in accordance
with the operating command entered by the user via the operating member 93.
[0046] The detection unit 15 detects a physical quantity representing a spatial relationship
of at least one of the tip tool 20 or the tool body 10 with respect to the work target
W1. The detection unit 15 detects the physical quantity in a state where the operating
member 12 is being operated.
[0047] As shown in FIG. 1, the detection unit 15 includes a rangefinder sensor 151, a camera
152, and a physical quantity extraction unit 153. In this embodiment, the physical
quantity extraction unit 153 is implemented as a computer system serving as the control
unit 11.
[0048] As shown in FIG. 3, the rangefinder sensor 151 is held by the tool body 10. The (rangefinder
sensor 151 of the) detection unit 15 detects, as the physical quantity, a parameter
related to the distance between the tool body 10 (more specifically, a part, holding
the rangefinder sensor 151, of the tool body 10) and the work target W1. In this case,
the parameter related to the distance is a distance. That is to say, the rangefinder
sensor 151 detects the distance between the tool body 10 and the work target W1 (i.e.,
the distance from the rangefinder sensor 151 to the work target W1).
[0049] The rangefinder sensor 151 may be, for example, a time-of-flight (TOF) rangefinder
sensor. The rangefinder sensor 151 includes a light-emitting unit and a photosensitive
unit. The rangefinder sensor 151 detects, based on the time it takes for the light
emitted from the light-emitting unit and reflected from the work target W1 to be incident
on the photosensitive unit, the distance between the (rangefinder sensor 151 of the)
tool body 10 and the work target W1. The rangefinder sensor 151 may be either a direct
TOF sensor or an indirect TOF sensor, whichever is appropriate.
[0050] The rangefinder sensor 151 transmits a signal representing the physical quantity
thus detected (i.e., the distance between the tool body 10 and the work target W1)
to the control unit 11. Alternatively, information for use to detect the distance
between the tool body 10 and the work target W1 (e.g., the interval between a point
in time the light-emitting unit emits light and a point in time when the photosensitive
unit receives the light) may be detected by the rangefinder sensor 151 and the distance
itself between the tool body 10 and the work target W1 may be detected by another
arithmetic processing unit (such as the physical quantity extraction unit 153) by
reference to that information.
[0051] In the electric tool 1 according to this embodiment, the detection unit 15 includes
a plurality of rangefinder sensors 151. More specifically, the detection unit 15 includes
three rangefinder sensors 151. Alternatively, the detection unit 15 may include two
rangefinder sensors 151 or four or more rangefinder sensors 151.
[0052] The plurality of rangefinder sensors 151 are arranged symmetrically to each other
with respect to the output shaft 133 when viewed from in front of the electric tool
1. For example, the three rangefinder sensors 151 may be arranged at equal intervals
(i.e., at an interval of 120 degrees) around the output shaft 133. For example, when
viewed from in front of the electric tool 1, one of the three rangefinder sensors151
is disposed right over output shaft 133, another rangefinder sensor 151 is disposed
on the lower right side of the output shaft 133, and the other rangefinder sensor
151 is disposed on the lower left side of the output shaft 133. As used herein, the
"front" refers to a direction pointing from the tool body 10 toward the tip tool 20
and the phrase "when viewed from in front of the electric tool 1" means viewing the
electric tool 1 from in front of the tip tool 20 toward the tool body 10.
[0053] The plurality of rangefinder sensors 151 transmit the physical quantities thus detected
(i.e., the distances from the rangefinder sensors 151 to the work target W1) to the
physical quantity extraction unit 153.
[0054] The physical quantity extraction unit 153 detects, based on the values of the distances
detected by the plurality of rangefinder sensors 151, respectively, a posture difference
indicating the degree of deviation in posture of either the tip tool 20 or the tool
body 10 with respect to the work target W1. That is to say, the detection unit 15
detects, as the physical quantity, the posture difference indicating the degree of
deviation in posture of either the tip tool 20 or the tool body 10 with respect to
the work target W1 based on the results of detection obtained by the plurality of
rangefinder sensors151 that detect respective distances to the work target W1. In
this embodiment, the physical quantity extraction unit 153 detects the posture difference
of the tool body 10 with respect to the work target W1. As used herein, the "posture
difference" refers to the degree of deviation of the posture of either the tool body
10 or the tip tool 20 (e.g., the tool body 10 in this example) with respect to the
work target W1 from a reference posture. In this case, the "reference posture" herein
refers to the posture of the tool body 10 in a state where the tool body 10 faces
up to the work target W1. Specifically, if one surface, facing the electric tool 1,
of the work target W1 is a planar, then the "reference posture" refers to the posture
of the tool body 10 in a state where an axial line of the tip tool 20 attached to
the tip tool attachment 134 is perpendicular to the counter surface of the work target
W1. In a specific example, the "posture difference" herein refers to the angle formed
between the direction of the axial line of the tip tool 20 obtained based on the distance
values detected by the plurality of rangefinder sensors 151, respectively, and the
direction of the axial line of the tip tool 20 in the reference posture (in a state
where the tip tool 20 faces up to the work target W1).
[0055] The physical quantity extraction unit 153 detects the posture difference based on
the difference between the plurality of (e.g., three in this example) distances that
have been detected by the plurality of (e.g., three in this example) rangefinder sensors
151, respectively. For example, in a situation where the counter surface of the work
target W1 is planar, if the plurality of distance values detected by the plurality
of rangefinder sensors 151, respectively, are equal to each other, then it can be
said that the tool body 10 faces up to the work target W1 (i.e., the posture difference
is zero). On the other hand, if the value of the distance detected by the upper rangefinder
sensor 151 is less than any of the values of the distances detected by the other two
rangefinder sensors151 (i.e., on the lower left and lower right sides), then it can
be said that the tool body 10 is tilted obliquely forward. The magnitude of the tilt
(i.e., a tilt angle with respect to the reference posture; i.e., the posture difference)
may be obtained based on the plurality of (i.e., three in this example) distance values
detected by the plurality of (i.e., three in this example) rangefinder sensors151,
respectively.
[0056] The physical quantity extraction unit 153 transmits a signal including the data about
the physical quantity thus obtained (i.e., the posture difference) to the control
unit 11.
[0057] The camera 152 is held by the tool body 10. The camera 152 shoots a subject in front
of the tool body 10. The camera 152 is mounted on the upper surface of the barrel
101 of the tool body 10, for example, (i.e., the upper surface in FIG. 3) to be ready
to shoot a subject in front of the tool body 10. The camera 152 has its angle of view
and position set to be able to shoot at least a frontend portion of the tip tool 20
(i.e., a part to be fitted into the head portion of the fastening member 200) and
at least a rear end portion of the fastening member 200 (i.e., a part including the
head portion). The camera 152 may be formed integrally with the tool body 10 to be
embedded in (e.g., the barrel 101 of) the tool body 10. Alternatively, the camera
152 may also be connected removably to a connector (e.g., a USB connector) provided
for the tool body 10 to be held by the tool body 10.
[0058] The camera 152 transmits the captured image to the physical quantity extraction unit
153.
[0059] The physical quantity extraction unit 153 obtains, based on the captured image generated
by the camera 152, a physical quantity representing a spatial relationship of at least
one of the tip tool 20 or the tool body 10 with respect to the work target W1. In
this embodiment, the physical quantity extraction unit 153 detects, based on the captured
image generated by the camera 152, a posture difference indicating the degree of deviation
in the posture of either the tip tool 20 or the tool body 10 with respect to the work
target W1. In particular, the physical quantity extraction unit 153 detects the posture
difference of the tip tool 20 with respect to the work target W1.
[0060] The physical quantity extraction unit 153 detects the posture difference by making
an image analysis of the captured image. As described above, the "posture difference"
herein refers to the degree of deviation in the posture of either the tip tool 20
or the tool body 10 (e.g., the tip tool 20 in this example) with respect to the work
target W1 from the reference posture. As used herein, the "reference posture" refers
to the posture of the tip tool 20 in a state where the tip tool 20 faces up to the
work target W1, for example. If the counter surface of the work target W1 is planar,
for example, then the "reference posture" herein refers to the posture of the tip
tool 20 in a state where the axial line of the tip tool 20 is perpendicular to the
counter surface of the work target W1. In one specific example, the "posture difference"
refers to the angle formed between the direction of the axial line of the tip tool
20 obtained from the captured image generated by the camera 152 and the direction
of the axial line of the tip tool 20 in the reference posture (in a state where the
tip tool 20 crosses at right angles with the work target W1).
[0061] The physical quantity extraction unit 153 detects the posture difference by making
an image analysis of the captured image generated by the camera 152. The physical
quantity extraction unit 153 obtains, based on the result of the image analysis, for
example, the angle formed between a normal to the counter surface of the work target
W1 (corresponding to the direction of the axial line of the tip tool 20 in the reference
posture) and the direction of the axial line of the tip tool 20 as the posture difference.
Alternatively, the normal to the counter surface of the work target W1 may be replaced
with the direction of the axial line of the fastening member 200.
[0062] As can be seen, obtaining the physical quantity using the camera 152 enables detecting
the physical quantity more definitely and obtaining the value of the optimum control
parameter more accurately.
[0063] The physical quantity extraction unit 153 transmits a signal representing the physical
quantity (posture difference) thus obtained to the control unit 11.
[0064] The communications unit 16 is a communications module for use to establish wireless
communication with the processor 9, for example. The communications unit 16 may establish,
for example, a short-range wireless communication compliant with the ZigBee (R) standard.
The communications unit 16 receives a signal including the tool information by a wireless
communication method from the processor 9. Also, the wireless communication established
between the communications unit 16 and the processor 9 may be a wireless communication
using radio waves as a propagation medium which is compliant with a communications
protocol such as the Specified Low Power Radio Station standard (a radio station requiring
no license) that uses the 920 MHz band, the Wi-Fi (R) standard, or the Bluetooth (R)
standard. Still alternatively, the communication between the communications unit 16
and the processor 9 may also be wired communication.
[0065] The storage unit 17 may include, for example, a read-only memory (ROM) or a nonvolatile
memory. Examples of the nonvolatile memory include an EEPROM and a flash memory. The
storage unit 17 stores a control program to be executed by the control unit 11. In
addition, the storage unit 17 also stores the tool information that has been transmitted
from the processor 9. The tool information includes information about the length of
the tip tool 20 attached to the tip tool attachment 134. In addition, the storage
unit 17 further stores "correspondence" to be described later.
[0066] As shown in FIG. 1, the control unit 11 further includes a parameter calculator 112.
The parameter calculator 112 calculates, based on the detection value of the physical
quantity that has been detected by the detection unit 15, an optimum value of the
control parameter related to the operation of the driving unit 13. The parameter calculator
112 obtains the optimum value of the control parameter by reference to the correspondence
stored in the storage unit 17.
[0067] The correspondence stored in the storage unit 17 associates a plurality of values
(optimum values) of the control parameter with a plurality of values that the physical
quantity (distance and posture difference) detected by the detection unit 15 may take.
The correspondence is stored in advance in the form of, for example, a data table
or a relational formula in the storage unit 17.
[0068] That is to say, the correspondence associates the control parameter related to the
operation of the driving unit 13 with the physical quantity (distance and posture
difference) representing the spatial relationship of at least one of the tip tool
20 or the tool body 10 with respect to the work target W1. In the electric tool system
100 according to this embodiment, the control parameter includes the maximum number
of revolutions of the motor 131 as described above. Thus, the correspondence associates
a plurality of values (optimum values) of the maximum number of revolutions with a
plurality of values that the physical quantity may take.
[0069] The parameter calculator 112 calculates, based on a detection value of the physical
quantity that has been detected by the detection unit 15, an optimum value of the
control parameter (maximum number of revolutions) in a state where the operating member
12 is being operated (e.g., the trigger switch 121 is being pulled). Then, the driving
controller 111 controls the operation of the driving unit 13 based on the optimum
value of the control parameter calculated by the parameter calculator 112.
[0070] The parameter calculator 112 calculates the optimum value of the control parameter
according to the parameter related to the distance which has been detected by the
detection unit 15. Specifically, the parameter calculator 112 calculates the optimum
value of the maximum number of revolutions of the motor 131 according to the distance
value that has been detected by the (rangefinder sensor 151 of the) detection unit
15. As used herein, the "distance value that has been detected by the detection unit
15" may be either the average value, maximum value, or minimum value of the distance
values that have been detected by the plurality of (e.g., three) rangefinder sensors
151, respectively, or the distance value that has been detected by a particular one
of the plurality of (e.g., three) rangefinder sensors 151.
[0071] The parameter calculator 112 changes, by reference to the correspondence, the optimum
value of the maximum number of revolutions of the motor 131 according to a variation
in the distance value detected by the rangefinder sensor 151 in a state where the
operating member 12 is being operated (e.g., the trigger switch 121 is being pulled).
That is to say, in a state where the motor 131 is running with the operating member
12 operated, the fastening member 200 is gradually screwed into the work target W1
by the tip tool 20, and therefore, the distance between the work target W1 and the
tool body 10 gradually varies accordingly. The parameter calculator 112 changes the
optimum value of the maximum number of revolutions according to this variation in
distance. Specifically, the parameter calculator 112 reduces the optimum value of
the maximum number of revolutions as the detection value of the distance decreases.
[0072] More specifically, the parameter calculator 112 calculates the distance L0 (refer
to FIG. 3) between the work target W1 and the tip tool 20 in accordance with the tool
information (e.g., the length of the tip tool 20) stored in the storage unit 17, the
distance between the work target W1 and the tool body 10 that has been detected by
the detection unit 15, and, if necessary, the distance from the rangefinder sensor
151 to the tip tool attachment 134. As shown in FIG. 4, if the distance L0 is equal
to or greater than the predetermined value L1 (i.e., in the region on the left of
the point where the distance L0 is the predetermined value L1 in FIG. 4), the parameter
calculator 112 sets the optimum value of the maximum number of revolutions at the
maximum value N1. On the other hand, if the distance L0 is less than the predetermined
value L1 (i.e., in the region on the right of the point where the distance L0 is the
predetermined value L1 in FIG. 4), the parameter calculator 112 sets the optimum value
of the maximum number of revolutions at a value equal to or greater than zero but
less than the maximum value N1. For example, if the distance L0 is less than the predetermined
value L1, the parameter calculator 112 sets the optimum value of the maximum number
of revolutions at a predetermined value N2 (where 0 ≤ N2 < N1).
[0073] This allows, when the fastening member 200 has just started to be fastened (when
L0 ≥ L1 is satisfied), the fastening operations to be done quickly by running the
motor 131 at high speeds (i.e., at the maximum value N1 of the maximum number of revolutions).
Meanwhile, as the fastening member 200 is going to be seated (i.e., when the distance
L0 becomes less than the predetermined value L1), the maximum number of revolutions
of the motor 131 decreases, so does the number of revolutions of the motor 131. Then,
in a state where the motor 131 is running at relatively low speeds (i.e., at a number
of revolutions less than the maximum value N1), the fastening member 200 is seated
on the work target W1. This enables reducing the kickback of the work target W1 and
other inconveniences which would be caused if the fastening member 200 were seated
while the motor 131 is still running at high speeds, for example.
[0074] The parameter calculator 112 calculates the optimum value of the control parameter
according to the posture difference detected by the detection unit 15. In this case,
the posture difference may be a value obtained based on the result of detection by
the rangefinder sensor 151 or a value obtained based on the captured image generated
by the camera 152, whichever is appropriate.
[0075] The parameter calculator 112 sets, if the posture difference falls outside of the
tolerance range, for example, the optimum value of the maximum number of revolutions
at zero. This may reduce the chances of the operations of fastening the fastening
member 200 being performed in a state where the tool body 10 is tilted with respect
to the work target W1 more significantly than expected. Consequently, this may reduce
the chances of causing inconveniences such as so-called "galling."
[0076] The advantage of this configuration will be described in comparison with an electric
tool as a comparative example. The electric tool according to the comparative example
reduces, at the beginning of the fastening operations started in response to an operating
command entered via the operating member, the number of revolutions of the motor compulsorily
to a value less than the maximum number of revolutions. Thus, the electric tool according
to the comparative example allows the posture difference to fall within the tolerance
range more easily, thus reducing the chances of causing inconveniences such as galling.
However, the electric tool according to the comparative example reduces the number
of revolutions of the motor compulsorily at the beginning of the fastening operations,
thus causing a decrease in the efficiency of operations.
[0077] In contrast, in the electric tool system 100 according to this embodiment, if the
posture difference is found to fall outside of the tolerance range at the beginning
of the operations of fastening the fastening member 200, the driving controller 111
does not allow the motor 131 to start running even when the operating member 12 is
operated to turn the trigger switch 121 ON. Thereafter, when the posture difference
falls within the tolerance range, the driving controller 111 sets the maximum number
of revolutions at the maximum value N1 to allow the motor 131 to start running. This
enables improving the efficiency of operations while reducing the chances of causing
inconveniences at the work target W1.
[0078] Optionally, the tolerance range of the posture difference may be changed as appropriate
according to the type of the tip tool 20, the type of the fastening member 200, and/or
the type of the work target W1, for example.
(3) Exemplary operation
[0079] Next, a specific exemplary operation of the electric tool system 100 according to
this embodiment will be described with reference to the flowchart shown in FIG. 5.
[0080] To perform fastening operations using the electric tool 1, first, the user enters
tool information by operating the operating member 93 of the processor 9 (in ST1).
The processor 9 transmits a signal including the tool information thus accepted to
the electric tool 1. On receiving the signal including the tool information from the
processor 9, the electric tool 1 has the tool information stored in the storage unit
17.
[0081] The user puts the electric tool 1 in a predetermined place and turns the trigger
switch 121 ON (in ST2). When the trigger switch 121 is turned ON, the detection unit
15 detects a physical quantity (in ST3). Specifically, the physical quantity extraction
unit 153 detects a posture difference based on the captured image generated by the
camera 152 and the rangefinder sensor 151 detects the distance to the work target
W1.
[0082] The (parameter calculator 112 of the) control unit 11 determines whether the posture
difference falls within the tolerance range or not (in ST4). If the posture difference
falls outside of the tolerance range (if the answer is NO in ST4), the control unit
11 sets the maximum number of revolutions of the motor 131 at zero to cause the motor
131 to stop running (or prevents the motor 131 from being activated) (in ST9).
[0083] On the other hand, if the posture difference falls within the tolerance range (if
the answer is YES in ST4), the (parameter calculator 112 of the) control unit 11 determines
whether the distance L0 between the work target W1 and the tip tool 20 is equal to
or greater than a predetermined value L1 (in ST5). If the distance L0 is equal to
or greater than the predetermined value L1 (if the answer is YES in ST5), then the
control unit 11 sets the maximum number of revolutions of the motor 131 at a maximum
value N1. Then, the (driving controller 111 of the) control unit 11 controls the driving
unit 13 based on the depth to which the trigger switch 121 has been pulled to prevent
the number of revolutions of the motor 131 from exceeding the maximum number of revolutions
(at the maximum value N1). This allows the user to perform operations at high speeds
using the electric tool 1 (in ST6).
[0084] While the user is performing the operations at high speeds, the detection unit 15
detects the physical quantity (including the distance and the posture difference)
as needed (in ST3). If the posture difference falls outside of the tolerance range
(if the answer is NO in ST4), the (parameter calculator 112 of the) control unit 11
sets the maximum number of revolutions of the motor 131 at zero to cause the motor
131 to stop running.
[0085] If the distance L0 is less than the predetermined value L1 (if the answer is NO in
ST5), the control unit 11 sets the maximum number of revolutions of the motor 131
at a predetermined value N2 (where N2 < N1). This allows the user to perform operations
at low speeds using the electric tool 1 (in ST7). While the user is performing operations
at low speeds, the rangefinder sensor 151 detects the physical quantity (distance)
as needed. Then, the (driving controller 111 of the) control unit 11 controls the
driving unit 13 based on the depth to which the trigger switch 121 has been pulled
to prevent the number of revolutions of the motor 131 from exceeding the maximum number
of revolutions.
[0086] When the distance L0 goes zero to have the operations done (if the answer is YES
in ST8), the control unit 11 causes the motor 131 to stop running (in ST9).
[0087] Note that the flow shown in FIG. 5 is only an exemplary procedure of the operation
of the electric tool system 100 and should not be construed as limiting. Optionally,
the processing steps shown in FIG. 5 may be performed in a different order from the
illustrated one, some of the processing steps shown in FIG. 5 may be omitted as appropriate,
and/or an additional processing step may be performed as needed. For example, the
physical quantity may be detected before the trigger switch 121 is turned ON (in ST2).
Also, even if the user is performing operations at low speeds (in ST7), the detection
unit 15 may also detect the posture difference and the (parameter calculator 112 of
the) control unit 11 may also determine whether the posture difference falls within
the tolerance range.
(4) Variations
[0088] Note that the embodiment described above is only an exemplary one of various embodiments
of the present disclosure and should not be construed as limiting. Rather, the exemplary
embodiment may be readily modified in various manners depending on a design choice
or any other factor without departing from the scope of the present disclosure. Next,
variations of the exemplary embodiment will be enumerated one after another. Note
that the exemplary embodiment described above and the variations to be described below
may be adopted in combination as appropriate.
[0089] In one variation, the control parameter related to the operation of the driving unit
13, for which the parameter calculator 112 calculates an optimum value thereof, is
not limited to the maximum number of revolutions of the motor 131 but may also be
the maximum value of a motor current supplied to the motor 131, for example, or the
maximum value of a duty of a PWM signal.
[0090] In another variation, the electric tool system 100 does not have to include the processor
9. In that case, the control unit 11 of the electric tool 1 may perform the function
of the tool information acceptor 921. For example, a code for reading the tool information
may be imprinted on the surface of the tip tool 20 itself and may be read when the
tip tool 20 is attached to the tip tool attachment 134 to allow the tool information
acceptor 921 to acquire the tool information.
[0091] In still another variation, the electric tool system 100 does not have to include
the tool information acceptor 921. For example, if only a tip tool 20 with a predetermined
length is attachable to the tip tool attachment 134, there is no need to acquire the
tool information.
[0092] In yet another variation, at least some functions of the electric tool 1 (such as
the function of the physical quantity extraction unit 153 and the function of the
parameter calculator 112) may be provided for the processor 9.
[0093] In yet another variation, the detection unit 15 may include only the physical quantity
extraction unit 153 with no cameras 152.
[0094] In yet another variation, the physical quantity extraction unit 153 may detect, based
on the captured image generated by the camera 152, either the distance between the
tool body 10 and the work target W1 or the distance L0 between the tip tool 20 and
the work target W1.
[0095] In yet another variation, the detection unit 15 may detect the posture difference
based on results of detection obtained by an acceleration sensor, for example. That
is to say, the configuration of the detection unit 15 for detecting the physical quantity
is not limited to the configuration including the rangefinder sensor 151 and the camera
152.
[0096] In yet another variation, the detection unit 15 may detect, as a parameter related
to the distance, the magnitude of variation (or a variation per unit time) in the
distance between the work target W1 and at least one of the tip tool 20 or the tool
body 10.
[0097] In yet another variation, the parameter calculator 112 may change the optimum value
of the maximum number of revolutions in multiple stages in a region where the distance
L0 is equal to or less than the predetermined value L1. Alternatively, the parameter
calculator 112 may change the optimum value of the maximum number of revolutions such
that as the distance L0 decreases, the optimum value of the maximum number of revolutions
decreases gradually.
(5) Aspects
[0098] As can be seen from the foregoing description, the exemplary embodiment and its variations
described above are specific implementations of the following aspects of the present
disclosure.
[0099] An electric tool system (100) according to a first aspect includes a driving unit
(13), an operating member (12), a driving controller (111), a tool body (10), a detection
unit (15), a storage unit (17), and a parameter calculator (112). The driving unit
(13) includes a motor (131). The driving unit (13) drives a tip tool (20) in rotation
by running the motor (131) and thereby has operations done on a work target (W1).
The operating member (12) is operated by a user. The driving controller (111) controls
operation of the driving unit (13) in accordance with an operating command entered
by the user via the operating member (12). The tool body (10) is a portable tool body.
The tool body (10) holds the driving unit (13), the operating member (12), and the
driving controller (111). The detection unit (15) detects a physical quantity representing
a spatial relationship of at least one of the tip tool (20) or the tool body (10)
with respect to the work target (W1). The storage unit (17) stores correspondence
which associates a control parameter related to the operation of the driving unit
(13) with the physical quantity. The parameter calculator (112) calculates, based
on a detection value of the physical quantity that has been detected by the detection
unit (15) and by reference to the correspondence, an optimum value of the control
parameter in a state where the operating member (12) is being operated. The driving
controller (111) controls the operation of the driving unit (13) based on the optimum
value of the control parameter calculated by the parameter calculator (112).
[0100] This aspect may reduce the chances of the work target (W1) turning into a defective
product, thus contributing to improving the efficiency of operations.
[0101] In an electric tool system (100) according to a second aspect, which may be implemented
in conjunction with the first aspect, the detection unit (15) includes a physical
quantity extraction unit (153) for obtaining the physical quantity based on a captured
image generated by a camera (152). The parameter calculator (112) calculates the optimum
value of the control parameter according to the physical quantity obtained by the
physical quantity extraction unit (153).
[0102] This aspect enables detecting the physical quantity more definitely by using the
camera (152) and thereby calculating the optimum value of the control parameter more
accurately.
[0103] In an electric tool system (100) according to a third aspect, which may be implemented
in conjunction with the first or second aspect, the detection unit (15) detects, as
the physical quantity, a parameter related to a distance between the work target (W1)
and at least one of the tip tool (20) or the tool body (10). The parameter calculator
(112) calculates the optimum value of the control parameter according to the parameter
related to the distance which has been detected by the detection unit (15).
[0104] This aspect allows the optimum value of the control parameter to be obtained dynamically
during the operations according to the parameter related to the distance.
[0105] In an electric tool system (100) according to a fourth aspect, which may be implemented
in conjunction with the third aspect, the control parameter includes a maximum number
of revolutions as an upper limit of a number of revolutions of the motor (131). The
parameter calculator (112) calculates an optimum value of the maximum number of revolutions
as the optimum value of the control parameter.
[0106] This aspect allows the optimum value of the maximum number of revolutions to be obtained
according to the value of the physical quantity detected.
[0107] In an electric tool system (100) according to a fifth aspect, which may be implemented
in conjunction with the fourth aspect, the detection unit (15) detects, as the parameter
related to the distance, the distance between the work target (W1) and at least one
of the tip tool (20) or the tool body (10). The parameter calculator (112) reduces
the optimum value of the maximum number of revolutions as the detection value of the
distance decreases.
[0108] This aspect enables reducing, for example, the kickback from the work target (W1)
which would be caused if the fastening member (200) were seated while the motor (131)
is running at high speeds, thus reducing the chances of the work target (W1) turning
into a defective product and thereby contributing to improving the efficiency of operations.
[0109] In an electric tool system (100) according to a sixth aspect, which may be implemented
in conjunction with any one of the first to fifth aspects, the detection unit (15)
detects, as the physical quantity, a posture difference, indicating a degree of deviation
in posture of at least one of the tip tool (20) or the tool body (10) with respect
to the work target (W1), based on detection results obtained by a plurality of rangefinder
sensors (151). Each of the plurality of rangefinder sensors (151) detects a distance
to the work target (W1). The parameter calculator (112) calculates the optimum value
of the control parameter according to the posture difference detected by the detection
unit (15).
[0110] This aspect allows the optimum value of the control parameter to be obtained according
to the posture difference.
[0111] In an electric tool system (100) according to a seventh aspect, which may be implemented
in conjunction with any one of the first to sixth aspects, the control parameter includes
a maximum number of revolutions as an upper limit of a number of revolutions of the
motor (131). The detection unit (15) detects, as the physical quantity, a posture
difference indicating a degree of deviation in posture of at least one of the tip
tool (20) or the tool body (10) with respect to the work target (W1). The parameter
calculator (112) sets the optimum value of the maximum number of revolutions at zero
when the posture difference falls outside of a tolerance range.
[0112] This aspect may reduce the chances of causing inconveniences such as so-called "galling,"
thus contributing to improving the efficiency of operations.
Reference Signs List
[0113]
- 100
- Electric Tool System
- 10
- Tool Body
- 111
- Driving Controller
- 112
- Parameter Calculator
- 12
- Operating Member
- 13
- Driving Unit
- 131
- Motor
- 15
- Detection Unit
- 151
- Rangefinder Sensor
- 152
- Camera
- 153
- Physical Quantity Extraction Unit
- 17
- Storage Unit
- 20
- Tip Tool
- 200
- Fastening Member
- W1
- Work Target