Technical Field
[0001] The present invention relates to an elevator door control device. More specifically,
the present invention relates to an elevator door control device in which abnormal
states during elevator door opening and closing operations are avoided by detecting
the abnormal states with good precision.
Background Art
[0002] Conventional elevator door control devices detect whether or not an abnormality exists
during elevator door opening and closing operations while monitoring increases in
a motor current that accompany abnormal states in door opening and closing operations
caused by an elevator user's body or finger getting caught in or pulled into a door
portion. Door operation is reversed when an abnormality is detected.
[0003] Specifically, the focus is placed on the fact that there are differences between
normal door operation and abnormal door operation as to how the motor current changes
over time. The motor currents during normal door operation are successively measured
at each floor according to the door operation over time, and then simply stored without
performing any arithmetic processing. Motor current values during actual door opening
and closing and motor current values for each corresponding floor (the stored data)
are compared according to the door operation over time. An abnormality in the door
is detected for cases where a difference between the two is equal to or greater than
a prescribed value (refer to Patent Document 1, for example).
[0004] It should be noted that, it is clear that the conventional elevator door control
devices described above are equivalent in operation to those in which abnormal states
of the door are detected when the value of the motor current during actual door opening
and closing exceeds a value obtained by adding a predetermined margin torque (prescribed
value) to the value of the motor current during normal operation over time for the
corresponding door, and the door is then made to operate in reverse.
[0005] Further, from the viewpoint of electrical machinery engineering, it is clear that
the motor current described here can be considered to be a substitute for the motor
torque. In addition, from the viewpoint of control engineering, it is clear that the
motor torque and a motor torque command may be handled as equivalents in practice
because it can be considered that normally a large numerical difference does not exist
between a command and a control variable in a system implementing a feed back control.
Accordingly, the motor current, the motor torque, and the motor torque command are
treated as having equivalent meanings in the present specification.
[Patent Document 1] JP 54-120157 A (pages 4 and 5)
[0006] As described above, the conventional elevator door control devices perform door abnormality
detection by adding a predetermined margin torque to a motor torque waveform (motor
current waveform) or a torque command waveform that accompanies actual door opening
and closing operations simply stored without performing arithmetic processing, and
using the resultant waveform as an abnormality detection torque pattern for abnormal
torque detection. In practice, the actual torque waveform and the torque command waveform
changes with each door opening and closing operation due to disturbances attributable
to changes over time, such as debris in the vicinity of the door and friction accompanying
door opening and closing. Accordingly, there is a problem in that erroneous abnormality
detection, not correct abnormality detection, occurs for cases where the added margin
torque is too small, and where the torque waveform or the torque command waveform,
which becomes a basis for the abnormality detection torque pattern, is inappropriate.
[0007] That is, the sensitivity for detecting torque abnormalities becomes higher if the
margin torque added to the actual torque command pattern, which is simply stored without
arithmetic processing, is made to be a small value. However, abnormalities are judged
to have occurred for cases where the torque command increases due to torque fluctuations
caused by debris in the vicinity of the door, friction, and the like which accompany
door opening and closing. Unnecessary door reversal operations therefore repeatedly
occur. Conversely, although the number of erroneous operations becomes fewer if the
margin torque is increased, there is a problem in that the level of danger to the
elevator user increases because the permissible values of the torque command become
larger as a result of the abnormality detection torque pattern becoming larger.
[0008] The torque fluctuations that cause these problems depend upon long term torque fluctuations
caused by changes over time, such as changes in the shape of door panels, in addition
to short term torque fluctuations caused by debris in the vicinity of the door, friction,
or the like.
[0009] The present invention has been made in order to solve problems like those described
above. An object of the present invention is to provide an elevator door control device
having a high abnormality detection precision, with few erroneous detentions of door
opening and closing operation abnormalities, by creating an abnormality detection
torque pattern for appropriately detecting torque abnormalities while taking into
account long term fluctuations and short term fluctuations in an actual torque waveform
(motor current waveform) and a torque command waveform.
[0010] It should be noted that, in the present invention, the term abnormality detection
means detecting whether or not there is an abnormality in door opening and closing
operations while monitoring increases in the motor current or increases in the motor
torque command or in the motor torque, which accompany an abnormal state in door opening
and closing operations such as an elevator user's body or finger getting caught in
or pulled into a door portion during opening and closing operations of the elevator
door. That is, the term abnormality detection means detecting abnormality states in
door opening and closing operations by detecting abnormal motor current, motor torque
commands, or motor torques.
Disclosure of the Invention
[0011] According to the present invention, there is provided an elevator door control device
that outputs a torque command corresponding to a speed command to an elevator door
driving unit to perform opening and closing control of the elevator door, the device
including: a reference torque command pattern generator portion that generates a reference
torque command pattern by collecting and arithmetically processing a plurality of
patterns of the torque command; and a torque abnormality detection portion that detects
abnormalities in the torque command based on the reference torque command pattern.
Brief description of the drawings
[0012]
Fig. 1 is a schematic diagram that shows an example of an elevator door control device
according to Embodiment 1 of the present invention;
Fig. 2 is a diagram of a relationship between a torque command (reference torque command)
and an abnormality detection torque pattern in the elevator door control device according
to Embodiment 1 of the present invention;
Fig. 3 is a diagram for explaining operation during torque abnormality detection in
the elevator door control device according to Embodiment 1 of the present invention;
Fig. 4 is a diagram that shows a torque command when door opening and door closing
operations are repeated in the elevator door control device according to Embodiment
1 of the present invention;
Fig. 5 is a diagram that shows time series data for a sampled torque command, and
an example of a method for computing an arithmetic mean in order to generate a reference
torque command pattern in the elevator door control device according to Embodiment
1 of the present invention;
Fig. 6 is a diagram that shows time series data of a torque command for five times
in a trial direction in the elevator door control device according to Embodiment 1
of the present invention;
Fig. 7 is an explanatory diagram of a computational formula, showing a median process
for the time series data of a torque command for five times in a trial direction in
the elevator door control device according to Embodiment 1;
Fig. 8 is a flowchart that shows operation of a reference torque command pattern generator
portion in the elevator door control device according to Embodiment 1 of the present
invention;
Fig. 9 is a flowchart that shows operation of an abnormality detection torque pattern
generator portion and an abnormality avoiding unit in the elevator door control device
according to Embodiment 1 of the present invention;
Fig. 10 is a schematic diagram that shows an example of an elevator door control device
according to Embodiment 2 of the present invention; and
Fig. 11 is an explanatory diagram that shows operation during torque abnormality detection
in the elevator door control device according to Embodiment 2 of the present invention.
Best Modes for carrying out the Invention
Embodiment 1
[0013] Fig. 1 is a schematic diagram that shows an example of an elevator door control device
according to Embodiment 1 of the present invention. As shown in Fig. 1, a pulse generator
2 is connected directly to a motor shaft of a door driver motor 1 that drives an elevator
door mechanism portion including an elevator door. The pulse generator 2 generates
pulse information that shows positions of the door driver motor 1. Further, a current
detector 3 detects a load current on the door driver motor 1. It should be noted that
a vector control induction motor, a brushless DC motor, or the like is assumed to
be used as the door driver motor 1.
[0014] A speed command portion 4 outputs a speed command according to a predetermined speed
pattern. An adder portion 5 outputs a speed deviation between the speed command output
by the speed command portion 4, and an actual motor speed (feedback speed) obtained
from the pulse generator 2 through a speed conversion portion. A speed control portion
6 outputs a motor current command, which corresponds to a torque command, to the door
driver motor 1 as a torque command corresponding to the output speed deviation, thus
performing speed control.
[0015] More precisely, the adder portion 7 obtains a deviation in current from the load
current, which is output by the current detector 3, with respect to the motor current
command (torque command) that is output from the speed control portion 6. The motor
current command is then output to a current control portion 8. The current control
portion 8 generates the load current for driving the door driver motor 1 according
to the input current deviation, thus performing speed control of the door driver motor
1. The current control portion 8 implements vector control based on phase information
from the pulse generator 2, for example, when performing speed control.
[0016] Further, a reference torque command pattern generator portion 9 includes a torque
command pattern series storage portion 9A and a reference torque command pattern output
portion 9B. The torque command pattern series storage portion 9A stores a plurality
of torque command patterns. The plurality of torque command patterns are formed by
a plurality of torque commands sampled at each floor according to elapsed time, door
position, and the like for door opening and closing operations at each floor based
on floor information that is input from the outside.
[0017] Further, the reference torque command pattern output portion 9B generates and outputs
a reference torque command pattern for each floor. The reference torque command pattern
for each floor is obtained by computation based on the torque commands at each common
sampling for a plurality of torque command patterns for each floor from among the
plurality of torque command patterns that are stored in the torque command pattern
series storage portion 9A.
[0018] The reference torque command patterns for each floor that are output from the reference
torque command pattern output portion 9B are input to an abnormality detection torque
pattern generator portion 10. The abnormality detection torque pattern generator portion
10 adds a predetermined margin torque to the input reference torque command patterns,
generating an abnormality detection torque pattern that becomes a reference for detecting
whether or not the torque commands output by the speed control portion 6 are abnormal.
[0019] Further, an abnormality avoiding unit 11 includes, in an inner portion thereof, a
torque abnormality detection portion 12. The torque abnormality detection portion
12 inputs the torque command that is output from the speed control portion 6, and
reads in the abnormality detection torque pattern generated by the abnormality detection
torque pattern generator portion 10. The torque abnormality detection portion 12 detects
that door opening and closing operations are abnormal when the torque command exceeds
the abnormality detection torque pattern. Having detected abnormal door opening and
closing, the torque abnormality detection portion 12 outputs an abnormality avoidance
command to the speed command portion 4. Having received the abnormality avoidance
command, the speed command portion 4 reduces the speed of the speed command to be
output, outputting it as a new speed command (reverse operation speed command) for
reversing operation of the elevator door.
[0020] That is, the abnormality avoiding unit 11 reduces the speed of the speed command,
thus avoiding an abnormality state, for cases where the torque command exceeds the
abnormality detection torque pattern. Alternatively, the abnormality avoiding unit
11 may reduce the speed of the speed command, and in addition, cause the elevator
door to operate in reverse, thus avoiding an abnormality state.
[0021] Operation of the abnormality detection torque pattern generator portion 10 and the
torque abnormality detection portion 12 in the elevator door control device according
to Embodiment 1 are explained next. Fig. 2 is an explanatory diagram that shows a
relationship between the reference torque command pattern and the abnormality detection
torque pattern during door opening. Fig. 3 is an explanatory diagram that shows operation
of the torque abnormality detection portion 12.
[0022] The reference torque command pattern generator portion 9 generates the reference
torque command pattern shown in Fig. 2 from the torque command that is output each
time the speed control portion 6 opens and closes the door at each floor. The reference
torque command pattern is generated here by arithmetic processing, described below,
such as median processing, simple mean processing, and additive averaging processing
with a forgetting coefficient of the torque command data for cases where opening and
closing is performed five times, for example. The abnormality detection torque pattern
generator portion 10 adds a predetermined margin torque to the generated reference
torque command pattern, thus generating the abnormality detection torque pattern.
[0023] Further, as shown in Fig. 3, the torque abnormality detection portion 12 detects
that there is an abnormality when the torque command increases, exceeding the abnormality
detection torque pattern, as a result of abnormal door opening and closing, and instructs
the speed control portion 4 to operate the door in reverse.
[0024] It should be noted that Fig. 2 and Fig. 3 are examples, and show assumed door operations
during door opening. It is not necessary to limit the present invention to only door
operations during door opening. The configuration of the reference torque command
pattern generator portion 10 and the torque abnormality detection portion 12 can also
be similarly achieved for door operation during door closing.
[0025] With the elevator door control device of Embodiment 1, the torque command pattern
is input by a plurality of door opening and closing trials (repeated opening and closing),
as described below. A reference torque command pattern that is not excessively influenced,
whether in the long-term or the short-term, by sudden disturbances is found by arithmetic
processing of the input torque command. It should be noted that the most suitable
reference torque command pattern is a representative value of the torque command pattern
during normal operation, and is also referred to as a torque command pattern that
does not cause the abnormality detection sensitivity to deviate. It is therefore understood
that using a central value, that is, an average value, of fluctuations in the torque
command pattern due to opening and closing the door a plurality of times is appropriate
in order not to cause the abnormality detection sensitivity to deviate with respect
to torque fluctuations caused by debris in the vicinity of the door accompanying door
opening and closing, friction, and the like, as described above.
[0026] However, for cases where the average value of the torque command pattern is computed
with respect to a repetition direction, it is necessary to pay attention to the fact
that removing influence due to sudden disturbances during repetition counting, as
discussed next, is a very important problem.
[0027] Fig. 4 is an explanatory diagram that shows a torque command when repeating door
opening and door closing operations. In Fig. 4, a horizontal axis shows a count of
pulses output from the pulse detector 2 (that is, door positions), while a vertical
axis shows a torque command. Fig. 4 shows door opening and door closing operations
repeated over an entire day and night on a two-dimensional diagram. Further, Fig.
4 is a waveform that includes mistakes (waveform distortions due to sudden disturbances)
whereby an operator mistakenly touches the door during door opening and door closing
operations performed over an entire day and night.
[0028] From these results it can be understood that it is necessary to compute an average
value of the torque command by considering not only waveform fluctuation, but also
the influence of sudden disturbances, in generating the reference torque command pattern
that does not cause the abnormality detection sensitivity to deviate. It is necessary
to collect a plurality of time series data, which is the waveform of the repeated
torque command, in order to compute the average value.
[0029] Operation of the reference torque command pattern generator portion 9 that generates
and stores the reference torque command pattern is explained next.
[0030] As shown in Fig. 5, in addition to a time direction during door opening and closing,
a direction of the number of door openings and door closings is defined as a trial
direction and explained. Two computation methods shown in Fig. 5, that is, (1) trial
direction simple average processing and (2) trial direction additive average processing
with a trial direction forgetting constant are used as average value computing methods
in order to generate appropriate reference torque command patterns. Computation by
the trial direction simple average process and the trial direction additive average
process with a trial direction forgetting constant tend to receive excessive influence
by sudden disturbances, however, because average computation with respect to the trial
direction is performed with both methods by using a linear filter. It is necessary
to take a very large number of averages for each, or it is necessary to make the forgetting
coefficient extremely small, in order to reduce the influence of sudden disturbances.
However, removing the influence of sudden disturbances is not very easy in these computations.
[0031] Median processing using a non-linear filter, called a median filter, that outputs
a median value is used with the elevator door control device according to Embodiment
1. The median filter is one type of majority decision filter, known as a noise elimination
method, used in image processing, and the medial filter is characterized by being
able to easily eliminate the influence of sudden disturbances.
[0032] Operation of the median filter is explained in detail here. As shown in Fig. 6, torque
commands A, B, C, D, and E appear with time series data for five times in a trial
direction. For example, data is arranged in a time series such as a(1), a(2), a(3),
a(4), a(5), a(6), and a(7), for example, with the first time series data A. That is,
the numbers within parenthesis are sampling numbers.
[0033] Median processing for a case in which there is time series data of the torque command
for five times in the test direction is computed by equations shown in Fig. 7. A number
i within parenthesis means a sampling number here. "Median [ ]" means an operator
that performs a computation in which a value (median value) in a middle rank is extracted
from results of sorting (arranged in ascending order) the data in [ ].
[0034] The influence of sudden disturbances that originally did not need to be considered
door opening and closing abnormalities, for example a sudden disturbance due to an
operator touching the door or the like, can easily be removed by this method. This
is because the influence of disturbances appears in a maximum value and a minimum
value. Accordingly, the influence of sudden disturbances that are not considered door
opening and closing abnormalities can be excluded in the computation results by using
the median value as the computation result of the average computation method of the
torque command in order to generate an appropriate reference torque command pattern.
The influence of sudden disturbances that are not considered to be door opening and
closing abnormalities can thus be eliminated by computing the median value of the
fluctuations in the torque command pattern. Therefore the reference torque command
pattern generator portion 9 can thus generate an appropriate reference torque command
pattern that does not cause the abnormality detection sensitivity to deviate.
[0035] That is, the reference torque command pattern generator portion 9 in the elevator
door control device according to Embodiment 1 gets the reference torque command pattern
by median processing of the torque command of each common sampling of the stored plurality
of torque command patterns.
[0036] Further, the reference torque command pattern may also be found by using a simple
averaging process or an additive averaging process with a forgetting coefficient as
a substitute for median processing. However, when using these processes, it is necessary
to take a very large number of averages, or to make the forgetting coefficient extremely
small, respectively.
[0037] An example of specific operation for a case where median processing is used in the
reference torque command pattern generator portion 9 is explained next. Fig. 8 is
a flowchart that shows operation of the reference torque command pattern generator
portion 9. The reference torque command pattern generator portion 9 performs floor
recognition (step S1), smoothes the torque command waveform through filter processing
by using a normal linear filter or the like on the torque command for door opening
and closing (step S2), and divides positions from completely open to completely closed
into 32 portions, for example, by motor angles, and buffers torque commands (a(1),
a(2), ..., a(32)) at each of these points (step S3).
[0038] Next, the reference torque command pattern generator portion 9 confirms whether or
not five sets of data in trial directions (independently for both door opening and
door closing) have been acquired (step S4), finds a median value for five sets x 32
points of data by employing the median processing shown in Fig. 7 when the five sets
of data that are shown in Fig. 6 have been acquired (step S5), and stores the reference
torque command pattern found from the 32 points of data in an EEPROM (electrically
erasable programmable read-only memory) (step S6).
[0039] The operation of reference torque command pattern generator portion that acquires
five sets of data in the trial directions (independently for both door opening and
door closing) and generates the reference torque command pattern has been explained
here. Strictly speaking, however, it is necessary to be careful to apply the operations
described here independently for each floor during operation of the elevator.
[0040] In addition, median processing may also be performed while updating the five sets
of time series data in the test directions so as to include the most recent data,
performing a moving average filter computation. A reference torque command pattern
that is appropriate for counterbalancing short term and long term torque command fluctuations
can thus be generated. As a result, it can be considered that short term torque command
fluctuations are eliminated by taking the median value of the fluctuations, and further,
long term fluctuations are taken in by taking the median value of the fluctuations.
Further, median processing need not be performed for each data update. Updating of
data may also be performed after acquiring five sets of data (updating once per five
data sets, after 5, 10, 15 and the like).
[0041] Operation of the abnormality detection torque pattern generator portion 10 is explained
next. It should be noted that values computed so as to have a constant force at door
edges for each door opening and closing position may be used here as a margin torque
that is added to the reference torque command pattern when finding the abnormality
detection torque pattern.
[0042] Fig. 9 is a flowchart that shows an example of operation of the abnormality detection
torque pattern generator portion 10 and the abnormality avoiding unit 11. The abnormality
detection torque pattern generator portion 10 reads in the 32 points of the reference
torque command pattern stored in the EEPROM in step S6 in Fig. 8 (step S10), adds
a margin of torque (margin torque) corresponding to a 10 kgf portion at the door edge,
for example, to each point of the reference torque command pattern (step S11), performs
a process of employing the largest of three adjacent points in the 32 points of data,
to which the margin torque has been added, as the data for that position (a step S12),
and determines the abnormality detection torque pattern by linear interpolation between
each point (step S13).
[0043] Next, the torque abnormality detection portion 12 of the abnormality avoiding unit
11 compares the torque command and the abnormality detection torque pattern (step
S14), judges that the door opening and closing operations are abnormal when the torque
command is equal to or greater than the abnormality detection pattern and performs
door reversal operations (step S15). For cases where the torque command is less than
the abnormality detection pattern, the torque abnormality detection portion 12 judges
that the door operation is normal and continues the opening and closing operations.
[0044] According to the elevator door control device of Embodiment 1, the abnormality detection
torque pattern can thus be generated based on the actual torque pattern in consideration
of short term and long term torque command fluctuations, and in addition, the influence
of sudden disturbances that are not considered to be door opening and closing abnormalities
can be eliminated. The abnormality detection sensitivity therefore does not deviate,
and it becomes unnecessary to make the predetermined torque excessively large when
the abnormality detection torque pattern is generated. As a result, the door abnormality
detection precision can be increased, and an elevator door having a high level of
safety can be provided.
Embodiment 2
[0045] Fig. 10 is a schematic diagram that shows an example of an elevator door control
device of Embodiment 2 of the present invention. Differing from Embodiment 1 shown
in Fig. 1, an abnormality torque command correcting unit 13, which is a unit relating
to computation of a torque command correction, is newly added as an abnormality avoiding
unit 11A. Other elements are the same as, or equivalent to, the configuration of the
elevator door control device of Embodiment 1 described above.
[0046] With the elevator door control device of Embodiment 2, the torque command and the
abnormality detection torque pattern are compared in the torque abnormality detection
portion 12 to detect torque abnormalities, similar to Embodiment 1. For cases where
an abnormality of the torque command is detected, the abnormality avoiding unit 11A
outputs an abnormality avoiding command for avoiding the abnormality to the speed
control portion 4. The speed control portion 4 reduces the speed command, and in addition,
outputs a new speed command for reversing the operation of the elevator door driving
unit.
[0047] However, a considerable response delay until the changes of the speed command described
above are actually reflected in the door control device is generated. Further, there
is a problem in that the torque command may inadvertently exceed the abnormality detection
torque pattern for cases where pulse shape noise is superimposed onto the torque command,
making correct abnormality detection impossible. The elevator door control device
of Embodiment 2 is an embodiment that takes this problem into consideration.
[0048] The abnormality torque command correcting unit 13 includes a correction torque command
computation portion 13A that computes a correction torque command by a correction
method described below based on a deviation between the torque command output by the
speed control portion 6 and the abnormality detection torque pattern generated by
the abnormality detection torque pattern generator portion 10. The abnormality torque
command correcting unit 13 also includes an output torque command switching portion
13B that switches to output the correction torque command computed by the correction
torque command computation portion 13A from the torque command that is output from
the speed control portion 6 when the torque command is larger than the abnormality
detection torque pattern, and on the other hand, switches to output the torque command
that is output from the speed control portion 6 when the torque command is equal to
or less than the abnormality detection torque pattern.
[0049] That is, a new torque command is generated in an inner portion of the abnormality
avoiding unit 11A, specifically by the equations shown below. The new torque command
is the correction torque command based on the size relationship between the abnormality
torque pattern and the torque command, or the torque command that is output from the
speed command portion 6.
(1) Abnormality present (abnormality detection torque pattern ≤ torque command):
correction torque command = abnormality detection torque pattern + (torque command
- abnormality detection torque pattern) x coefficient (s)
The torque command is the torque command before correction, the correction torque
command is the torque command after correction, and the coefficient ε is defined by
0 ≤ ε < 1.
(2) Normal operation (abnormality detection torque pattern > torque command):
new torque command = torque command
[0050] That is, the coefficient ε possesses a meaning of a compression ratio for an exceeding
amount when the torque command (torque command before correction) exceeds the abnormality
detection torque pattern. Through use of the coefficient ε, suppression of the torque
command while maintaining the size relationship between the abnormality detection
torque pattern and the torque command (torque command before correction) within a
period of time set in advance based on a time that corresponds to the response delay
relating to an abnormality detection recognition time, elevator door reverse operation,
or the like. It should be noted that it is necessary to determine a specific value
for the coefficient ε while taking the size of the maximum permissible torque and
the size of the torque fluctuations into account.
[0051] Further, the abnormality detection torque pattern within the period of time set in
advance based on the time of the response delay relating to the abnormality detection
recognition time, reverse operation of the elevator door, or the like may also be
controlled to be spread across the torque command, for example. This case corresponds
to setting the coefficient ε = 0.
[0052] Next, Fig. 11 is a diagram for explaining operation of the elevator door control
device of Embodiment 2. Fig. 11 is a diagram showing that the torque command pattern
during abnormality generation becomes the corrected torque command that is compressed
by correction computation of the torque command value in the inner portion of the
abnormality avoiding unit 11A within an abnormality detection confirmation time T
(or within an amount of time set in advance corresponding to the response delays relating
to elevator door reversal operations or the like).
[0053] Further, Fig. 11 is a diagram that shows that the door operation switches to reverse
operation, which is abnormality avoiding operation, after an abnormality is first
judged for a case where the torque command before correction continues to exceed the
abnormality detection torque pattern within the abnormality detection confirmation
time, which is a certain predetermined period of time.
[0054] That is, the abnormality avoiding unit 11A in the elevator door control device according
to Embodiment 2 can prevent inadvertent abnormality avoidance operations that accompany
erroneous detection due to the influence of noise and the like, and further, can prevent
the torque command from becoming excessively large. The abnormality avoiding unit
11A does so by suppressing the torque command to an order that just exceeds the abnormality
detection torque pattern within the certain predetermined period of time for cases
where the torque command exceeds the abnormality detection torque pattern.
[0055] According to the elevator door control device of Embodiment 2, the torque command
can be suppressed to an order that just exceeds the abnormality detection torque pattern,
and sudden door opening and closing operations due to the generation of an excessively
large torque can be suppressed by the abnormality avoiding unit 11A for cases in which
the abnormality detection torque pattern exceeds the torque command.
[0056] Further, a problem existed in that the torque command inadvertently exceeds the abnormality
detection torque pattern when pulse shape noise exists superimposed onto the torque
command. With the elevator door control device according to Embodiment 2, however,
even if pulse shape noise exists superimposed onto the torque command, reliable abnormality
detection becomes possible by setting the abnormality detection confirmation time,
where an abnormality in the door opening and closing operations is first detected
when the torque command exceeds the abnormality detection torque pattern for a certain
predetermined period of time (abnormality detection confirmation time), for example.
In addition, excessively large torque generation can be suppressed during the abnormality
detection confirmation time until the abnormality avoiding unit 11A operates. Abnormalities
during door opening and closing can thus be reliably detected with good precision,
and door safety with a high likelihood of avoiding abnormalities can be achieved.
Industrial Applicability
[0057] According to the present invention as described above, dispersion in an abnormality
detection torque pattern is eliminated, and it becomes unnecessary to make an added
predetermined margin torque excessively large when setting a reference torque command
pattern. As a result, an elevator door control device having a high degree of safety,
in which door abnormality detection precision can be increased and erroneous detection
of door opening and closing operation abnormalities are reduced, can be provided.