JP4532176B2 - Control method for power assisted transport device and power assisted transport device - Google Patents

Description

  The present invention relates to a transfer device used for moving a sick person, a baggage, and the like, and more particularly to a control technology for a transfer device that supplies an assist force during movement by an electric motor.

  In hospitals, nursing homes, factories, warehouses, etc., a large number of transfer devices powered by motors are used, such as electric beds and stretchers, food carts and cargo carts. In such a conveying apparatus, driving wheels driven by an electric motor are attached to a main body frame having casters arranged at four corners, and assist force during movement is supplied by the driving wheels. Further, an electric motor, a battery for power supply, a controller for motor control, and the like are attached to the main body frame. On the main body frame, a mat is placed if it is a bed, and a cargo bed is provided if it is a carriage.

  In this type of transport device, the drive wheels are installed so as to be moved up and down by an electric actuator. In order to obtain the assist force by the driving wheel, an appropriate frictional force is required between the floor surface and the driving wheel, and the driving wheel needs to be brought into contact with the floor surface with an appropriate pressing force. For this reason, a pressing mechanism using a spring is provided between the main body frame and the conveying device, and the driving wheel is pressed against the floor surface with a predetermined load by the repulsive force of the spring. A frictional force is generated between

Further, a handling device is generally provided with a power assisting conveyance device. However, Japanese Patent Laid-Open No. 11-262111 discloses a configuration for detecting the force applied to the handle and controlling the assisting force. ing. There, sensors for detecting an operating force are provided at the left and right bases of the handle, and the force applied to the handle when the transport device is moved is detected by both sensors. Then, based on the detected left and right handle operating forces, the rotations of the left and right drive wheels arranged on both sides of the apparatus are adjusted to appropriately control the assist force and the traveling direction of the transport device.
Japanese Utility Model Publication No. 48-44793 JP 60-122561 JP JP 7-257387 A JP-A-8-175381 Japanese Patent Laid-Open No. 11-262111 Japanese Patent Application No. 2004-23883

  However, in a transport device that performs drive control based on the handle operating force, if one of the left and right sensors fails, the correct handle operating force cannot be grasped. The entire assist system stops. However, when such an event occurs during movement, the transport device stops suddenly, and there is a problem that a heavy load is imposed on the operator. In particular, an electric bed for a hospital has a weight of about 400 kg, and it is quite difficult for a nurse alone to move it without power assistance.

  Also, if the transport device suddenly stops in a narrow passage or elevator, or in a passage with a height difference or a step due to a sensor failure, the transport device cannot be moved easily and the device becomes an obstacle. There was also a problem of end. If the transport device occupies a narrow passage, it will hinder the traffic of people who use the passage, which will not only give the user a very uncomfortable feeling, but also in the hospital passage, the passage of a stretcher that transports emergency cases will not be allowed. May interfere.

  An object of the present invention is to ensure a minimum power assist even when a sensor for detecting a handle operating force breaks down and to move a transport device to a place where it does not get in the way.

The control method of the power-assisted transfer device according to the present invention includes a first sensor that detects the rotational speed of a driving wheel driven by an electric motor, and a second sensor that is attached to the handle and detects an operating force of the handle. And a control method of a power assisted transfer device that controls a driving assist force applied by the drive wheel based on detection values of the first and second sensors, wherein the first and second the sensors are provided on right and left, respectively, whereas when the sensor side has failed, characterized by continuing the application of the drive-assisting force to a predetermined device stop condition is provided.

In the present invention, even if one of the left and right sides of the first sensor and the second sensor provided in the left and right pair breaks down, the conveying device does not stop immediately on the spot, and the preset device The driving assistance force is ensured until the stop condition is satisfied. For this reason, in the event of a sensor failure, the transport device can be moved to a safe and unobstructed location for the time being, preventing the transport device from being trapped in a narrow passage, etc. Can be avoided.

  In the control method for the power-assisted transfer device, the end of transfer of the transfer device after the failure of the sensor is set as the device stop condition, and the application of the travel assist force is continued until the transfer by the transfer device is ended after the failure. Anyway. Further, the passage of a predetermined time after the failure of the sensor may be used as the apparatus stop condition, and the application of the driving assist force may be continued until the predetermined time has elapsed after the failure.

The control method of the power-assisted transport device, when the sensor of one side fails, regards the input from the failed said sensor the same as the input from the normal the sensor on the other side of the drive-assisting force The grant may be continued.

  In the control method of the power assisted transfer device, the first sensor may be installed in the left and right electric motors connected to the drive wheels, respectively. Further, the second sensor may be installed on the left and right of the handle.

  In the control method of the power-assisted transfer device, the travel assisting force may be reduced under a predetermined condition until the device stop condition is satisfied. For example, by reducing the driving assistance force stepwise or abruptly decreasing at a certain point in time, the operating force can be changed, so that the operator can be notified of the occurrence of a failure and the failure state can be recognized. .

  In the control method of the power assisted transfer apparatus, after the apparatus stop condition is satisfied, the application of the travel assist force may be limited. For example, after the equipment stop condition is met, by prohibiting the application of driving assistance force, the power assist is prohibited after the transport device is evacuated urgently due to the occurrence of a failure. it can.

Power-assisted transport device of the present invention is provided in pair, a first sensor for detecting the rotational speed of the drive wheels driven by an electric motor, provided on the right and left, mounted on the handle of the handle a second sensor for detecting the operating force, and controls the drive-assisting force based on the steering force detected by said first and second sensor, when the sensor of the right and left one side fails, predetermined wherein the device stop condition of and a control means for continuing the application of the drive-assisting force until provided.

In the present invention, even if one of the left and right sides of the first sensor and the second sensor provided in the left and right pair breaks down, the conveying device does not stop immediately on the spot, and the preset device The driving assistance force is ensured until the stop condition is satisfied. For this reason, at the time of a sensor failure, it is possible to move the transport device to a safe and unobtrusive place for the time being. For this reason, it is possible to prevent the transfer device from being neglected in a narrow passage or the like, and to prevent the transfer device from becoming an obstacle on the passage.

According to the control method of the power assisted transport device of the present invention, the first sensor for detecting the rotational speed of the driving wheel and the second sensor for detecting the handle operating force are provided. When one side of the first and second sensors provided in a pair of left and right in the transfer device with power assist that controls the driving assist force based on the detection value of the sensor fails, a predetermined device stop condition is provided. The application of the travel assisting force is continued until the right and left side sensors break down, so that the transport device does not stop immediately on the spot and travels until a preset device stop condition is met. Auxiliary power is secured. For this reason, in the event of a sensor failure, the transport device can be moved to a safe and unobstructed location, preventing the transport device from getting stuck in a narrow passage or the like, and the transport device becomes an obstacle on the passage Can be avoided.

  Further, in the control method for the power-assisted transport device according to the present invention, the operating force of the transport device is changed by reducing the travel assisting force under a predetermined condition until the device stop condition is satisfied, so that the operator It is possible to happily notify the occurrence of a failure. Thereby, it becomes possible to make an operator recognize a failure state more reliably.

On the other hand, according to the power assisting conveyance device of the present invention, the pair of left and right first sensors for detecting the rotational speed of the driving wheel in the conveying device to which the traveling assist force is applied by the driving wheel driven by the electric motor. A sensor and a pair of left and right second sensors for detecting the steering operation force. The driving assist force is controlled based on the detection values of the first and second sensors, and the left and right side sensors break down. In this case , since the control means for continuing the application of the driving assist force is provided until the predetermined apparatus stop condition is satisfied, even if the sensor on the left or right side breaks down, the transport apparatus does not stop immediately on the spot, The driving assist force is ensured until the set device stop condition is satisfied. For this reason, in the event of a sensor failure, the transport device can be moved to a safe and unobstructed location, preventing the transport device from getting stuck in a narrow passage or the like, and the transport device becomes an obstacle on the passage Can be avoided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a front view showing an example of an electric bed (transport device) for a hospital to which the control method according to the first embodiment of the present invention is applied, and FIG. 2 is a plan view showing an outline of the electric bed shown in FIG. The hospital electric bed according to the present embodiment includes a drive unit 1 and a bed unit 2. A motor 1 and various actuators are accommodated in the drive unit 1, and a mat 3 is placed on the bed unit 2. The bed portion 2 is supported by an arm 4 attached to the drive unit 1. The arm 4 is driven by the drive unit 1, and the height and posture of the bed unit 2 can be changed by the vertical movement of the arm 4.

  Safety fences 5 are attached to both sides of the bed portion 2. A bed moving handle 6 is attached to the front end side (the user's head side) of the bed portion 2. Here, the front and rear mean the longitudinal direction of the bed, and the side means both ends in the width direction (left and right direction) orthogonal to the longitudinal direction. As shown in FIG. 3, one handle 6 is provided on each of the left and right sides (6L, 6R), and a handle operating force sensor 7 (7L, 7R; second sensor, provided on the front end of the bed 2). Hereinafter, it is connected to the sensor 7. A control panel 8 is disposed between the handles 6, and a power switch 8a, an emergency stop switch 8b, a bed lift switch 8c, an LED display panel 8d, and the like are provided.

  The sensor 7 detects an operation load applied to the handle 6 when the bed is moved. The handle 6 is connected to a torsion bar (not shown) in the sensor 7, and a torsional displacement occurs in the torsion bar in accordance with the operating force of the handle 6. The sensor 7 measures the direction and amount of the torsional displacement using a potentiometer, and calculates the direction and magnitude of the operating force applied to the handle 6 based on the measured value. The sensor 7 individually detects the handle operating force by the left and right sensors 7L and 7R, and the traveling direction of the bed is also controlled based on the detected value.

  For example, when the operator pushes the handle 6 to advance the bed, the torsion bar is twisted in one direction by the pressing force of the handle 6, and the traveling direction of the bed is detected from the twist direction at this time. In addition, if the handle 6 is pressed strongly, the torsion angle of the torsion bar increases, and the torsion angle changes due to the handle pressing force. Based on this, a change in the force of pressing the bed can be detected. Further, when the outputs of the sensors 7L and 7R are compared and it is detected that the force pushing the left handle 6L is large, it is determined that the operator is going to bend the bed to the right. Conversely, when the force pushing the right handle 6R is large, it is determined that the operator is trying to bend the bed to the left.

  FIG. 4 is a perspective view showing the configuration of the drive unit 1. The drive unit 1 has a configuration in which a drive unit 12, an elevating actuator 13, and the like are provided on a steel frame 11. The steel frame 11 includes a main frame 11a extending in the front-rear direction and a connecting bar 11b provided so as to connect the main frames 11a and extending in the width direction. Casters 14 are attached to the lower surfaces of both ends of the main frame 11a. As shown in FIG. 1, a synthetic resin cover 15 is attached to the frame 11, and FIG. 4 shows a state in which the cover 15 is removed.

  The drive unit 12 is placed on the motor base 16. In the drive unit 12, two sets of a DC motor 17 (17L, 17R) and a speed reduction mechanism 18 (18L, 18R) are provided. Two rotating shafts 19 project from the left and right sides of the drive unit 12, and the rotation of the motor 17 is decelerated by the speed reduction mechanism 18 and output to the rotating shaft 19. Drive wheels 21 (21L, 21R) are fixed to each rotary shaft 19. The drive wheel 21 includes a wheel 22 and a rubber tire 23 fixed to the rotary shaft 19.

  The drive unit 12 is further provided with a vehicle speed sensor 39 (39L, 39R; first sensor, hereinafter abbreviated as sensor 39). The sensor 39 is composed of a multipolar magnetized magnet attached to the rotating shaft of the motor 17 and a magnetic detecting element that is disposed in the vicinity of the magnet and outputs a pulse signal when the magnetic pole changes. When the motor 17 rotates, a rotation pulse signal is output from the magnetic detection element according to the motor rotation speed. The rotational speed of the motor 17 and the rotational speed of the drive wheel 21 have a correlation, and the rotational speed of the drive wheel 21, that is, the vehicle speed can be detected by detecting the motor rotational speed by the sensor 39.

  A tower 24 is erected on the motor base 16. The tower 24 is connected to the lifting / lowering actuator 13, and the drive unit 12 moves up and down by the operation of the lifting / lowering actuator 13, so that the driving wheel 21 contacts and separates from the floor surface (traveling surface) 25. FIG. 5 is an explanatory diagram showing a connection structure between the drive unit 12 and the lift actuator 13. As shown in FIG. 5, the base 24 a of the tower 24 is rotatably supported on the arm 27 by a pivot 26. The arm 27 is fixed to the connecting bar 11b, and the motor base 16 is supported by the frame 11 so as to be swingable in the vertical direction (X direction in FIG. 5) about the pivot 26.

  A long hole 28 is formed in the upper portion of the tower 24. A pin 31 attached to the plunger 29 is inserted into the long hole 28 so as to be movable in the front-rear direction (left-right direction in the figure). The plunger 29 is attached to the upper part of the tower 24 so as to be movable in the front-rear direction, and is connected to the plunger 33 of the elevating actuator 13 via a spring 32. The elevating actuator 13 is driven by a DC motor 34, and the plunger 33 operates in the Y direction in FIG. The left end of the lifting actuator 13 in the figure is supported by a bracket 35 fixed to the connecting bar 11b so as to be swingable.

  As described above, the motor base 16 is connected to the lift actuator 13 via the spring 32. When the elevating actuator 13 is actuated to extend the plunger 33, the tower 24 is pushed through the spring 32, the plunger 29, and the pin 31, and the motor base 16 is rotated clockwise in FIG. Thereby, the drive wheel 21 moves to the floor surface 25 side and is pressed against the floor surface 25 with a predetermined ground load. On the other hand, when the plunger 33 contracts, the motor base 16 rotates counterclockwise around the pivot 26. As a result, the drive wheel 21 is detached and raised from the floor surface 25 and stored in a position separated from the floor surface 25.

  The frame 11 is further provided with a battery 36 for power supply, a controller (control means) 37 for motor control, an actuator 38 for bed posture control, and the like. The battery 36 supplies power to the motors 17 and 34, the controller 37, the actuator 38, and the like. The controller 37 is connected to the control panel 8 and performs drive control of each motor, actuator, etc. in accordance with an input instruction from the operator.

  FIG. 6 is a block diagram showing the configuration of the control system of the controller 37. The controller 37 is provided with input circuits 42 and 43, a drive output circuit 44, a power supply circuit 45 and a power supply input circuit 46 with the CPU 41 as the core. The input circuits 42 (42L, 42R) are connected to the sensors 7L, 7R, respectively, and a torque signal indicating the operating force of the left and right handles 6 is input. The input circuit 43 (43L, 43R) is connected to the sensors 39L, 39R, respectively, and receives a vehicle speed signal indicating the rotational speed of the left and right drive wheels 21.

  The drive output circuit 44 (44L, 44R) is connected to the left and right motors 17L, 17R. The motors 17L and 17R are PWM-controlled by the CPU 41, and a PWM duty command value is output from the CPU 41 to the drive output circuit 44. In response to this, the drive output circuit 44 supplies the motor 17 with a pulse voltage corresponding to the command value. The power circuit 45 is connected to the battery 36, and power is supplied to the CPU 41 from the battery 36 via the power circuit 45 and the power input circuit 46.

  In such an electric bed for hospitals, the following control is performed for the failure of the sensors 7 and 39. FIG. 7 is a flowchart showing the processing procedure of the control method according to the first embodiment of the present invention. In the control method of the first embodiment, it is first confirmed in step S1 whether or not a failure has occurred during the previous processing. If a failure has occurred in the sensor 7 or the sensor 39 last time, the process proceeds to step S12, and the operation at the time of failure is performed.

  FIG. 8 is a flowchart showing a processing procedure of the operation at the time of failure. As shown in FIG. 8, at the time of a failure, first, in step S21, the LED display panel 8d in the control panel 8 is blinked to notify the operator of the occurrence of a failure. Next, it progresses to step S22, the driving wheel 21 is stopped, a bed is made into a stop state, and a routine is exited. Note that not only a visual failure notification by the LED display panel 8d but also an acoustic failure notification by a buzzer or the like can be used together. Further, it may be displayed on the LED display panel 8d which of the sensors 7 and 39 is faulty.

  If no previous failure has occurred, the process proceeds from step S1 to step S2 to perform normal operation. That is, drive control of the drive wheels 21L and 21R is performed based on the steering wheel operation force detected by the sensor 7 and the vehicle speed detected by the sensor 39. While performing this control, the process proceeds to step S3 to check whether or not a failure has occurred in the sensors 7 and 39. If no failure has occurred, the process returns to step S2 to continue normal operation.

  On the other hand, if the occurrence of a failure is confirmed in step S3, the process proceeds to step S4, and the occurrence of the failure is stored in an external storage device (memory) (not shown) disposed in the controller 37. Thereafter, the process proceeds to step S5, and an error is displayed on the LED display panel 8d in the control panel 8 for failure warning.

  After the error display, the process proceeds to step S6, and it is confirmed whether or not the failure that has occurred is a failure mode in which the operation can be continued. For example, when both the left and right sensors 7L and 7R and the sensors 39L and 39R fail, the subsequent operation should not be continued. In the case of such a failure, the process proceeds to step S13, and the failure operation shown in FIG. 8 is performed. Do. On the other hand, in the case of a failure mode in which the operation can be continued, such as failure of only one side sensor 7L, 39L, the process proceeds from step S6 to step S7, and the state of the failed side sensor 7L, 39L is changed to the normal side. Similar processing to the sensors 7R and 39R is performed.

  Here, no signals are output or abnormal signals are currently output from the sensors 7 and 39 on the failure side, and the output signals from there cannot be used as they are. Conventionally, in such a state, the entire system is stopped because a normal transport operation is impossible, and this has caused the above-described problems. On the other hand, in the control method according to the present invention, focusing on the fact that the normal sensors 7 and 39 remain, it is considered that the same input as that of the normal sensor is input to the sensors 7 and 39 on the failure side. Control that can surpass the steep spot by ensuring the limited straight-ahead movement.

  Therefore, in this control, for example, when the sensor 7L has failed, the sensors 7L and 7R are considered to be in the same state in step S7, and then in step S8, based on the input of the normal sensor 7R, the current handle Calculate the operating force. After obtaining the operating force, the process proceeds to step S9, and the output of the motor 17 is reduced so that the assisting force is smaller by a certain percentage than the assisting force corresponding to the calculation result so that the operator can recognize the failure. At this time, the operator feels that the bed has become heavier and feels the failure state.

  For example, if the sensor 39L fails, the sensors 39L and 39R are considered to be in the same state in step S7, and then the current vehicle speed is calculated based on the input of the normal sensor 39R in step S8. After obtaining the vehicle speed, the process proceeds to step S9, and the output of the motor 17 is reduced so that the assist force is smaller by a certain percentage than the assist force corresponding to the calculation result so that the operator can recognize the failure.

  After the assist force is reduced in step S9, the process proceeds to step S10, and it is detected whether or not the conveyance process is completed. The end of conveyance is determined by ON / OFF of the power switch 8a. If the power switch 8a is in the ON state and the conveyance is not completed, the process returns to step S6 to check the failure mode (S6) and input the sensor. After the identification (S7), the operation force and the vehicle speed are calculated (S8), and the assist force is reduced (S9). At this time, in step S8, the assist force is further reduced at a certain rate from the previous assist force. As a result, the assist force gradually decreases as a failure occurs, and a larger operating force is required, so that the operator can experience the failure more clearly.

  The operator who recognizes the failure due to the reduced assist force takes into consideration the environment where the bed is currently placed, and if the bed does not interfere with the surroundings, it will be stopped as needed to investigate the cause of the failure and repair it. Do. On the other hand, when the bed is in a narrow passage, the bed is moved to a wide place while recognizing the failure state in order to move the bed to a place where it does not get in the way. In this control, steps S6 to S9 are set so that the latter treatment can be performed, whereby the bed is moved to a safe and unobstructed place.

  When the bed is moved to an appropriate place and stopped, it is determined in step S10 that the conveyance has been completed, and when the power switch 8a is turned off, the process proceeds to step S11, where electric conveyance is prohibited. The processes in steps S6 to S9 are so-called emergency evacuation procedures, and during that time, the operation continues to have a failure. Therefore, such a state should be kept to a minimum, and after the minimum necessary operation, it is required to stop the power assist operation unless the failure is repaired. Therefore, after the bed is moved as appropriate, the electric transfer operation is prohibited in step S11 with the end of transfer as an apparatus stop condition, and the routine is exited.

  Therefore, the power assist by the motor 17 is not performed even if the power switch 8a is turned on again after the bed in which the failure has occurred after the power switch 8a is turned off and the conveyance is completed. That is, when the power switch 8a is turned on again, the process proceeds from step S1 to step S12 based on the failure history stored in the external storage device in step S4, and the bed stop process is performed along with the blinking of the LEDs. That is, after the failure occurs, only manual movement can be performed after the minimum operation.

  As described above, according to the control method of the present invention, even if one of the input system sensor 7 and the sensor 39 breaks down, the bed does not stop immediately, and the minimum necessary movement operation is ensured. For this reason, even if a failure occurs in the sensors 7 and 39, it is possible to suppress the adverse effects caused by the stoppage of the apparatus such as the bed becoming an obstacle on the passage. Further, when the sensor 7 or 39 fails, the LED blinks or the operating force increases, so that the failure of the apparatus is accurately transmitted to the operator. Furthermore, since the operation at the time of the failure is extremely limited, and the second electric transfer after the failure is prohibited, continuous use in a failure state can be avoided.

  Next, a control method that is Embodiment 2 of the present invention will be described. FIG. 9 is a flowchart showing the processing procedure of the control method according to the second embodiment of the present invention. The control of the following embodiment is also executed in the bed shown in FIG. In the following embodiments, the same members and portions as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the control method of the second embodiment, the operation after the failure is limited in time. Also in the control of FIG. 9, it is first confirmed in step S31 whether or not a failure has occurred during the previous processing. If a failure has occurred in the previous time, the process proceeds to step S44, and a failure operation similar to the process of FIG. 8 is performed. If no failure has occurred in the previous time, the process proceeds from step S31 to step S32 to perform a normal operation, and the process proceeds to step S33 to check whether or not a failure has occurred in the sensors 7 and 39. If no failure has occurred, the process returns to step S32 to continue normal operation.

  If a failure has been confirmed in step S33, the failure is stored in the external storage device in step S4, and an error is displayed on the LED display panel 8d in step S5. Thereafter, a timer is set in step S36. After the timer is set, the process proceeds to step S37 to check whether or not the failure that has occurred is a failure mode in which the operation can be continued. In the case of a failure in which the operation cannot be continued, the process proceeds to step S45, and the failure operation shown in FIG. 8 is performed.

  In the case of the failure mode in which the operation can be continued, the process proceeds from step S37 to step S38, and it is assumed that the same input as that on the normal side is input to the failure side sensors 7 and 39, and the current input based on the input in step S39. The steering wheel operation force and vehicle speed are calculated. After obtaining the operating force, the process proceeds to step S40, and the output of the motor 17 is reduced by a certain rate in order to reduce the assist force.

  After the assist force is reduced in step S40, the process proceeds to step S41, and the timer set in S36 is counted down. A predetermined time limit (for example, 5 minutes) is set in the timer in S36, and the time limit is started together with the assist force reduction process. After the timer countdown starts, the timer value is confirmed in step S42, and if it is not 0, the process returns to step S37. Then, similarly to S6 to S9 of the first embodiment, the assisting force is reduced at a constant rate by the processing of S37 to S40, and the operator is made to experience the failure.

  When the timer value becomes 0 in step S42, it is determined that the time limit has elapsed, and the process proceeds to step S43 where electric conveyance is prohibited. That is, the passage of the time limit is set as an apparatus stop condition, and the electric transfer operation is prohibited in step S43, and the routine is exited. During this time limit, the operator takes into consideration the environment in which the bed is currently placed, and moves the bed to an unobstructed location within this time limit. The remaining time of the time limit can also be displayed on the LED display panel 8d.

  In the control of the second embodiment, if the time limit is reached, even if the power switch 8a is turned off, if the power switch 8a is turned on again after that, the power assist operation is performed again although it is limited. In this regard, in the first embodiment, the power assist operation is not performed again when the power switch 8a is turned off. On the contrary, in the first embodiment, the power assist operation is performed in a limited form as long as the power switch 8a is not turned off. However, in the second embodiment, the power assist operation is stopped regardless of the situation after the time limit is exceeded. Is done.

It goes without saying that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention.
For example, in the above-described embodiment, an example in which the transfer device of the present invention is applied to a hospital bed is shown. However, the application target is not limited to a bed, and a stretcher, a meal transport cart, a wheelchair, and an electric vehicle for cargo handling. The present invention can be widely applied to a carrier device that performs power assist, such as a carriage. In the above-described embodiment, the drive unit 12 is arranged on one motor base 16, and the drive wheel 21 is lifted and lowered by the single lift actuator 13. Separate drive units 12 may be used, which may be mounted on separate motor bases 16 and individually actuated by two lift actuators 13.

  Furthermore, it is also possible to perform a combination of the control modes of the above-described embodiments. For example, after the control of the second embodiment, the control of the first embodiment is performed, a time limit is provided for the power assist operation after the failure, and after the time limit has elapsed, the subsequent electric transfer is prohibited at the end of the transfer. You may do it. Note that the above-described example of the time limit (5 minutes) is merely an example, and the time limit can be arbitrarily set. However, since it is harmful if it is too short or too long, about 3 to 10 minutes is preferable.

  In addition, in the above-described embodiment, it is assumed that the failure side sensor has the same input as that of the normal side sensor, and the current steering wheel operation force is calculated based on the input. May be fixed to a predetermined constant value. That is, until the end of conveyance or the elapse of the time limit is confirmed in S10 or S42, processing for regarding the outputs of the sensors 7 and 39 on the failure side as constant may be performed. In the case of the failure of the sensor 7, if such a control mode is adopted, the operator adjusts the bed moving speed by operating the handle on the normal side, but the difference in the driving force between the left and right drive wheels 21 due to the operator's control. Since it can be provided, it is possible not only to go straight but also to bend the direction of travel or to turn the bed.

  Further, in the above-described embodiment, the configuration in which the sensors 7L and 7R are provided on the left and right separate handles 6, respectively, but a single handle formed in an inverted U shape as in the transport vehicle disclosed in Japanese Patent Laid-Open No. 11-262111. The sensor means may be provided on the left and right bases. The number of sensor means is not limited to one each on the left and right. Further, in the above-described embodiment, the bed speed is detected using the motor rotation pulse, but a rotation sensor is arranged on the drive wheel 21 or the caster 14 and the rotation speed of the drive wheel 21 is confirmed using the output signal. Thus, the bed speed may be detected. In addition, the thing of various structures, such as a T-shaped thing, can be used for the form of a handle | steering-wheel.

  In addition, in the above-described embodiment, when a failure occurs in the input-system sensors 7 and 39, the process of making the sensor inputs the same is performed. When one side of the drive output circuit 44 fails, a process for adjusting the control duty of the motor 17 to the normal side is also possible.

It is a front view which shows an example of the electric bed for hospitals to which the control method which is Example 1 of this invention is applied. It is a top view which shows the outline | summary of the electric bed of FIG. It is explanatory drawing which shows the structure of the handle | steering-wheel attached to the electric bed of FIG. It is a perspective view which shows the structure of the drive part of the electric bed of FIG. It is explanatory drawing which shows the connection structure of the drive unit and raising / lowering actuator in a drive part. It is a block diagram which shows the structure of the control system of a controller. It is a flowchart which shows the process sequence of the control method of the conveying apparatus with power assistance which is Example 1 of this invention. It is a flowchart which shows the operation process at the time of failure in step S12 of FIG. It is a flowchart which shows the process sequence of the control method of the conveying apparatus with power assistance which is Example 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Drive part 2 Bed part 3 Mat 4 Arm 5 Safety fence 6, 6L, 6R Handle 7 Handle operation force sensor (2nd sensor)
8 control panel 8a power switch 8b emergency stop switch 8c bed lift switch 8d LED display panel 11 frame 11a main frame 11b connecting bar 12 drive unit 13 lift actuator 14 caster 15 cover 16 motor base 17, 17L, 17R DC motor 18, 18L, 18R Deceleration mechanism 19 Rotating shaft 21, 21L, 21R Drive wheel 22 Wheel 23 Rubber tire 24 Tower 24a Base 25 Floor surface (travel surface)
26 Pivot 27 Arm 28 Long hole 29 Plunger 31 Pin 32 Spring 33 Plunger 34 DC motor 35 Bracket 36 Battery 37 Controller 38 Actuator 39, 39L, 39R Vehicle speed sensor (first sensor)
41 CPU
42, 42L, 42R Input circuit 43, 43L, 43R Input circuit 44, 44L, 44R Drive output circuit 45 Power supply circuit 46 Power supply input circuit

Claims (9)

A first sensor for detecting the rotational speed of the driving wheel driven by the electric motor; and a second sensor attached to the handle for detecting an operating force of the handle. A control method for a power-assisted transfer device that controls a driving assist force applied by the drive wheel based on a detection value,
Said first and second sensors are respectively provided in the pair, whereas if the sensor side has failed, characterized in that continuously applied the drive-assisting force to a predetermined device stop condition is provided A control method for a power-assisted transfer device.   2. The control method for a power assisted transfer apparatus according to claim 1, wherein the stop condition is the end of transfer of the transfer apparatus after the failure of the sensor.   2. The method for controlling a power assisted transfer apparatus according to claim 1, wherein a predetermined time after the failure of the sensor is set as the apparatus stop condition. The control method of the power-assisted transport device according to any one of claims 1 to 3, when the sensor of one side fails, the input from the failed the sensor from normal the sensor on the other side The control method for the power-assisted transfer device is characterized in that the application of the travel assist force is continued assuming that the input is the same.   5. The control method for a power-assisted transfer apparatus according to claim 1, wherein the first sensor is installed in the left and right electric motors connected to the drive wheels, respectively. Control method for a power-assisted transfer device.   6. The control method for a power-assisted transport apparatus according to claim 1, wherein the second sensor is installed on the left and right of the handle. .   In the control method of the power assisted conveyance device according to any one of claims 1 to 6, wherein the driving assistance force is reduced under a predetermined condition until the device stop condition is satisfied. Control method for a power-assisted transfer device.   8. The power assist control method according to claim 1, wherein after the apparatus stop condition is provided, the application of the travel assist force is limited. Method for controlling a transfer device with a load. A first sensor that is provided in a pair of left and right and detects the rotational speed of a drive wheel driven by an electric motor;
A second sensor provided in a pair of left and right , attached to the handle and detecting the operating force of the handle ;
Controls the drive-assisting force based on the steering force detected by said first and second sensor, when the sensor of the right and left one side fails, the running until a predetermined apparatus stop condition is provided and control means for continuing the application of assist force, power-assisted transport device, characterized in that it comprises a.

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