Control device for conveyance auxiliary device and control method for conveyance auxiliary device

Abstract

Provided are a control device for a conveyance auxiliary device and a control method for a conveyance auxiliary device whereby it is possible to realize smooth switching when enabling assist control. The control device for a conveyance auxiliary device comprises: a main control unit 21 comprising an external force detection unit 30 for detecting external force input to a conveyance auxiliary device 100 for assisting with travel of a traveling tool 110, a control calculation unit 31 for calculating a command value 81 for realizing movement of the conveyance auxiliary device 100 in accordance with the external force detected by the external force detection unit 30, a switching unit 32 for switching the control calculation unit 31 so as to be enabled or disabled, and a smoothing processing unit 33 for performing processing for smoothing change in the movement speed of the conveyance auxiliary device 100 in response to switching of the control calculation unit 31 from the disabled state to the enabled state, in which said main control unit 21 outputs a control command value 82 corresponding to the command value 81; and a drive control unit 22 that controls a drive wheel 10 included in the conveyance auxiliary device 100 on the basis of the control command value 82 output from the main control unit 21.

Description

Control device for transport auxiliary device and control method for transport auxiliary device

[0001] The present invention relates to a control device for a transport auxiliary device and a control method for a transport auxiliary device.

[0002] There are known traveling assist devices that assist the traveling of traveling implements, such as dollies with swivel wheels, transport carts, mobile beds, stretchers, etc., which carry an object to be transported and are manually pushed by an operator to travel on a floor surface. The traveling assist device is attached to the traveling implement and generates driving force to assist the transportation of the traveling implement.

[0003] For example, Patent Document 1 discloses a transport assist device that can be attached to and operated on a medical bed. When an operator pushes a stationary bed, the transport assist device starts moving together with the bed. The transport assist device uses a force sensor to detect the amount of strain generated in the transport assist device. Next, the transport assist device uses a rotation sensor to detect the rotation of the wheels (Mecanum wheels) as the transport assist device moves together with the bed. When the wheels are rotating, the transport assist device starts assist control to drive the motor based on the strain detected by the force sensor.

[0004] Japanese Patent Application Laid-Open No. 2022-186415

[0005] Takahiko Ono, "Ride Comfort Model During Supine Position Transport," Proceedings of the 49th Japan Society of Automatic Control Engineers, 2006, Vol. 49, pp. 125-125. Takahiko Ono, et al., "Analysis of Blood Pressure Fluctuations Due to Acceleration and Deceleration During Supine Position Transport," Ergonomics, 2011, Vol. 47, No. 1, pp. 1-9.

[0006] However, in Patent Document 1, the motor is driven only when the worker pushes the running tool, the wheels of the transport assist device attached to the running tool start to rotate, and the rotation of the wheels is detected by a rotation sensor. While this allows the worker to transport the running tool with little effort, the assist force begins to act immediately after the worker applies operating force to the running tool to start moving unassisted, causing the running tool to accelerate the moment the assist force is generated. As a result, the ride comfort of the patient being transported by the running tool may be deteriorated.

[0007] For example, as disclosed in Non-Patent Document 1, the acceleration and discomfort experienced by a patient during transport in a supine position are related by a polynomial model in which the discomfort increases or decreases as the absolute value of the acceleration increases or decreases. Furthermore, as disclosed in Non-Patent Document 2, the acceleration experienced by a patient and fluctuations in blood pressure can be approximated by a proportional relationship, so careful transport with reduced acceleration is required when transporting a medical bed used primarily for sick patients. Note that even when the moving device is a stretcher or wheelchair other than a medical bed, discomfort may be caused to the occupant.

[0008] Furthermore, even when the traveling device is a handcart used to transport items other than patients, it is necessary to suppress acceleration. For example, when transporting liquids or gelatinous substances such as medicines or beverages, it is necessary to prevent the contents from spilling out of the container or the container from tipping over due to speed changes caused by the generation of an assist force.

[0009] One way to prevent sudden changes in the traveling speed of the traveling implement is to constantly monitor the acceleration and restrict it to stay within a predetermined range. However, this method requires responsive control of the acceleration immediately after the assist control is activated, which complicates the acceleration monitoring system and the control calculations.

[0010] The present invention has been made in consideration of the above, and aims to provide a control device for a transport assist device and a control method for a transport assist device that can achieve smooth switching when enabling assist control.

[0011] A control device for a transport auxiliary device according to one aspect of the present invention comprises an external force detection unit that detects an external force input to a transport auxiliary device that assists the travel of a traveling implement, a control calculation unit that calculates a command value that realizes the movement of the transport auxiliary device in accordance with the external force detected by the external force detection unit, a switching unit that switches the control calculation unit between enabled and disabled, and a smoothing processing unit that smooths changes in the movement speed of the transport auxiliary device in response to the control calculation unit being switched from disabled to enabled, a main control unit that outputs a control command value corresponding to the command value, and a drive control unit that controls the drive wheels of the transport auxiliary device based on the control command value output from the main control unit.

[0012] According to this, when the control calculation unit is switched from disabled to enabled, the smoothing processing unit can execute processing to suppress changes in the movement speed of the transport assist device. In other words, when the assist control is enabled, the control command value output to the drive control unit is suppressed from increasing suddenly, and changes in the driving force generated by the transport assist device are alleviated, thereby suppressing acceleration of the traveling implement due to the driving force of the transport assist device. This suppresses sudden speed changes when the assist control starts, allowing for smooth switching when the assist control is enabled.

[0013] In a control device for a transport assistance device according to one aspect of the present invention, the smoothing processing unit schedules the control gain of the control calculation unit or the output amount of the calculation result in the control calculation unit so as to smooth changes in the movement speed of the transport assistance device in response to switching of the control calculation unit from disabled to enabled.

[0014] According to this, by scheduling the control gain value or the output amount of the calculation result, it is possible to reliably suppress a sudden change in the command value calculated by the control calculation unit or the control command value input to the drive control unit, thereby reliably suppressing a sudden change in speed when the assist control is enabled.

[0015] In a control device for a transport assistance device according to one aspect of the present invention, the smoothing processing unit enables the smoothing process when the control calculation unit is switched from disabled to enabled, and disables the smoothing process after a certain period of time has elapsed.

[0016] This prevents sudden speed changes when the assist control is enabled, while performing assist control without smoothing in the steady state after a certain time has elapsed since switching. Therefore, even when smoothing processing is performed, it is possible to prevent a decrease in the responsiveness of the transport assist device in the steady state.

[0017] In the control device for a transport assist device according to one aspect of the present invention, the smoothing process is a low-pass filter process that attenuates high frequency components of the calculation result in the control calculation unit.

[0018] According to this, even if the calculation result of the control calculation unit changes suddenly when the control calculation unit is switched to enabled (i.e., if the calculation result has high-frequency components), the change in the control command value is attenuated by the low-pass filter processing. Therefore, when the assist control is enabled, it is possible to suppress a sudden change in the control command value input to the drive control unit. Furthermore, when the calculation result of the control calculation unit changes gradually (i.e., if the calculation result does not have high-frequency components), the calculation result does not attenuate or the attenuation is small, so it is possible to suppress a decrease in the responsiveness of the transport assist device when the assist control is enabled.

[0019] In a control device for a transport assistance device according to one aspect of the present invention, the main control unit further includes an operation amount calculation unit that detects an operation amount input to the transport assistance device and calculates a command value based on the detected value of the operation amount, and a synthesis unit that calculates a synthesized value by combining the calculation result of the control calculation unit and the calculation result of the operation amount calculation unit, and outputs the control command value corresponding to the synthesized value, and the smoothing processing unit performs the smoothing process in the synthesis value calculation by the synthesis unit.

[0020] This allows the user to operate the transport assist device using the controller, in addition to the assist control. Even in this case, smoothing processing is performed in the synthesis value calculation by the synthesis unit, so that control that suppresses sudden speed changes when the assist control is enabled can be realized while responding to the user's operation input.

[0021] A control method for a transport assistance device according to one aspect of the present invention includes the steps of detecting an external force input to a transport assistance device that assists the travel of a traveling implement, calculating a command value that realizes movement of the transport assistance device in accordance with the detected external force, determining whether the calculation of the command value has been switched to either valid or invalid, and when it is determined that the calculation of the command value has been switched from invalid to valid, performing a process to smooth the command value so as to suppress changes in the movement speed of the transport assistance device, and controlling drive wheels of the transport assistance device based on a control command value corresponding to the command value.

[0022] According to this, when the calculation of the command value is switched from disabled to enabled, the smoothing process can suppress changes in the movement speed of the transportation assist device. In other words, when the assist control is enabled, the control command value for the drive wheels is suppressed from increasing suddenly, and changes in the driving force generated by the transportation assist device are alleviated, thereby suppressing acceleration of the traveling tool due to the driving force of the transportation assist device. This suppresses sudden changes in speed when the assist control starts, allowing for a smooth switch when the assist control is enabled.

[0023] According to the present invention, it is possible to provide a control device for a transport assist device and a control method for a transport assist device that can achieve smooth switching when enabling assist control.

[0024] FIG. 1 is a perspective view showing a transport assist device and a traveling implement. FIG. 2 is an explanatory diagram showing a schematic configuration of the transport assist device. FIG. 3 is a block diagram showing a schematic configuration of a control device for the transport assist device according to the first embodiment. FIG. 4 is a block diagram showing an example configuration of a control device that controls the speed of the transport assist device. FIG. 5 is a graph showing an example of scheduling of the control gain of the control calculation unit. FIG. 6 is a graph showing an example of scheduling of the output amount of a command value. FIG. 7 is a flowchart explaining the operation of the control device for the transport assist device according to the first embodiment. FIG. 8 is a graph showing an example of the relationship between the moving speed of the traveling implement and time when assist control is switched from disabled to enabled. FIG. 9 is a block diagram showing a schematic configuration of a control device for the transport assist device according to the second embodiment. FIG. 10 is a block diagram showing an example configuration of a control device for the transport assist device according to the third embodiment.

[0025] Modes (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by a person skilled in the art and those that are substantially the same. Furthermore, the components described below can be combined as appropriate.

[0026] First Embodiment First, a description will be given of the configuration of a transport assist device 100. Fig. 1 is a perspective view showing the transport assist device 100 and a traveling device 110.

[0027] The transport assistance device 100 is connected to a traveling tool 110 and assists the traveling of the traveling tool 110 (transportation of an object by the traveling tool 110). The traveling tool 110 has wheels 111 and travels on a floor surface with an object to be transported on board. The wheels 111 are driven wheels. In other words, the traveling tool 110 does not have a self-propelled function (drive source) and travels by external force. Such traveling tools 110 are, for example, dollies, transport carts, mobile beds, stretchers, etc. The object to be transported is not particularly limited and may be a living being such as a person or an animal, or various objects such as a container of a medicinal solution or a beverage, or precision equipment. FIG. 1 shows an example in which the traveling tool 110 is a dolly. In this example, the traveling tool 110 moves when an operator applies external force to a handle 112.

[0028] The transportation assistance device 100 is mechanically connected (coupled) to the traveling tool 110 by a connecting portion 120. The transportation assistance device 100 applies a propulsive force to the traveling tool 110 via the connecting portion 120. In the example of FIG. 1 , the connecting portion 120 includes a connecting portion main body 121 provided on the transportation assistance device 100 and an attachment member 122 provided on the underside of the traveling tool 110. When the transportation assistance device 100 is positioned so as to be under the traveling tool 110, the connecting portion main body 121 engages with the attachment member 122, thereby connecting the transportation assistance device 100 to the traveling tool 110. In the example of FIG. 1 , the connecting portion main body 121 operates to be switchable between engagement and disengagement with the attachment member 122. Therefore, the transportation assistance device 100 can be freely connected to and disconnected from the traveling tool 110. Note that the form of mechanical connection between the transportation assistance device 100 and the traveling tool 110 is not particularly limited. The transportation assist device 100 can be connected to the traveling tool 110 without the attachment member 122 on the traveling tool 110. The transportation assist device 100 is not limited to being disposed on the underside of the traveling tool 110, and may tow the traveling tool 110 from a position in front of the traveling tool 110 away from the traveling tool 110, or may push the traveling tool 110 from the rear side of the traveling tool 110 to propel it.

[0029] <General Configuration of Transport Assist Device> Fig. 2 is an explanatory diagram showing the general configuration of the transport assist device 100. As shown in Fig. 2, the transport assist device 100 includes drive wheels 10 and a control device 20 that controls the drive wheels 10. The control device 20 and each drive wheel 10 are assembled to a housing 101.

[0030] The transportation assistance device 100 can include one or more drive wheels 10, and in the example of Fig. 2 includes a plurality of drive wheels 10. The drive wheels 10 are wheels that are rotationally driven by a drive source (motor 11).

[0031] The drive wheels 10 may be wheels capable of only forward and backward movement, or wheels capable of omnidirectional movement (such as omni-wheels or Mecanum wheels). The transport assistance device 100 includes a corresponding motor 11 and angle sensor 12 for each drive wheel 10. The motor 11 drives the drive wheels 10 to rotate. The transport assistance device 100 uses the motor 11 to generate propulsive force for propelling the traveling implement 110. The type of motor 11 is not particularly limited. For example, the motor 11 may be a brushless direct-current (BLDC) motor. The angle sensor 12 detects the rotation angle of the drive wheels 10. The type (detection method) of the angle sensor 12 is not particularly limited. For example, the angle sensor 12 may be a position detector such as a rotary encoder or a hall sensor. In addition to the drive wheels 10, the transport assistance device 100 may also include a driven wheel (not shown) that is not driven by the motor 11.

[0032] The control device 20 includes a main control unit 21 and a drive control unit 22. One main control unit 21 is provided, and a drive control unit 22 is provided for each drive wheel 10 of the transport assist device 100. The main control unit 21 and each drive control unit 22 are connected by a communication line.

[0033] The main control unit 21 controls the entire transport assist device 100 by outputting control command values ​​82 (see FIG. 3 ) to each drive control unit 22. The main control unit 21 is realized by a processing circuit such as a system LSI (Large Scale Integration) or a processor such as a CPU (Central Processing Unit) that executes a program stored in a memory or the like.

[0034] Each drive control unit 22 controls the drive of the corresponding drive wheel 10 under the control of the main control unit 21. Each drive control unit 22 is connected to the motor 11 and angle sensor 12 of the corresponding drive wheel 10 via a power line or the like. The angle sensor 12 outputs the current value of the angle of the corresponding drive wheel 10.

[0035] The transport assistance device 100 also includes a force sensor 40. The force sensor 40 is connected to the main control unit 21 via a power line or the like. The detection method of the force sensor 40 is not particularly limited, and various detection methods, such as electrical resistance (strain gauge), capacitance, piezoelectric, and optical detection, can be used. The force sensor 40 is provided in the connection unit 120 (connection unit main body 121, see FIG. 1 ) and detects the current value of the force applied to the transport assistance device 100. When a user applies force to the traveling tool 110, the force is transmitted to the transport assistance device 100 via the connection unit 120. Therefore, the force sensor 40 detects the force acting on the connection unit 120, thereby indirectly detecting the current value of the force applied to the traveling tool 110.

[0036] 3 is a block diagram showing an example of the configuration of the control device 20 of the transport assist device 100 according to the first embodiment. Note that in Fig. 3, only one set of a drive control unit 22 and a motor 11 is shown.

[0037] In the example of FIG. 3, the main control unit 21 includes an external force detection unit 30, a control calculation unit 31, a switching unit 32, a smoothing processing unit 33, and a command value conversion unit .

[0038] The external force detection unit 30 detects an external force input to the transport assistance device 100 that assists the traveling of the traveling implement 110. The external force detection unit 30 outputs a sensor value detected by the force sensor 40 as an external force detection value 80. Although the force sensor 40 is used here, the force sensor 40 does not have to be provided. For example, the current value of the external force may be estimated using a Kalman filter or an observer from the sensor value of the angle sensor 12, etc., and the result may be used as the external force detection value 80.

[0039] The control calculation unit 31 calculates a command value 81 that realizes the movement of the transportation assistance device 100 in accordance with the external force detected by the external force detection unit 30. That is, the control calculation unit 31 calculates a command value 81 for assist control that assists the traveling of the traveling tool 110 in accordance with the external force. Here, assist control refers to control that generates a driving force (assist force) corresponding to the magnitude of the external force in the direction of action of the external force detected by the external force detection unit 30 (i.e., the traveling direction). When assist control is enabled, the transportation assistance device 100 generates a driving force via the connection unit 120 that pushes the traveling tool 110 in the traveling direction (i.e., the direction of action of the external force). When the driving wheel 10 is rotationally driven by the motor 11, a frictional force is generated between the driving wheel 10 and the traveling surface, and this frictional force serves as a driving force that accelerates or decelerates the transportation assistance device 100 and the traveling tool 110. The control calculation unit 31 calculates the command value 81 for generating a driving force in assist control. When the assist control is enabled, the external force that the operator applies to the traveling tool 110 to travel the traveling tool 110 is reduced by the driving force applied by the transport assist device 100. When the assist control is disabled, the transport assist device 100 does not generate a driving force, and the external force is not reduced.

[0040] The switching unit 32 switches the control calculation unit 31 (calculation of the command value 81) between enabled and disabled. That is, the switching unit 32 can switch the assist control by the control device 20 of the transport assist device 100 between enabled and disabled. When the assist control is switched between enabled and disabled, the switching unit 32 detects the occurrence of the switch and outputs the detection result to the control calculation unit 31 and the smoothing processing unit 33.

[0041] Enabling the control calculation unit 31 (calculation of the command value 81) means enabling the assist control, in which the control calculation unit 31 calculates the command value 81 according to an external force and controls the drive wheels 10 in accordance with the calculation result of the command value 81. Disabling the control calculation unit 31 (calculation of the command value 81) means disabling the assist control, in which the control calculation unit 31 does not execute control of the drive wheels 10 in accordance with the calculation result of the command value 81. The method for disabling the control calculation unit 31 is not limited to a specific method, and any method may be used as long as it can substantially disable the calculation process by the control calculation unit 31. Possible methods for disabling the control calculation unit 31 include, for example, stopping the operation of the control calculation unit 31, not causing the control calculation unit 31 to calculate the command value 81, and not causing the control calculation unit 31 to control the drive wheels 10 in accordance with the command value 81. When the operation of the control calculation unit 31 is stopped or the calculation of the command value 81 is not executed, the command value 81 is not calculated in the first place, and thus the assist control is disabled. Possible methods for not controlling the drive wheels 10 according to the command value 81 include, for example, replacing the command value 81 with another value equivalent to a driving force of 0, not inputting the control command value 82 to the drive control unit 22, or stopping the operation of the drive control unit 22. In these cases, even if the command value 81 is calculated, the drive wheels 10 will not be controlled according to the calculation result of the command value 81, and therefore the assist control will be disabled.

[0042] The smoothing processing unit 33 performs processing to smooth changes in the movement speed of the transport assist device 100 in response to switching of the control calculation unit 31 from disabled to enabled. That is, when the assist control is enabled, the smoothing processing unit 33 performs processing to smooth the command value 81 so as to suppress changes in the movement speed of the transport assist device 100. The smoothing processing will be described later.

[0043] The command value conversion unit 34 converts the calculation result (command value 81) of the control calculation unit 31 into a control command value 82 for each drive wheel 10. The main control unit 21 outputs each control command value 82 converted by the command value conversion unit 34 to the corresponding drive control unit 22. In this way, the main control unit 21 outputs the control command value 82 corresponding to the command value 81 calculated by the control calculation unit 31.

[0044] The drive control unit 22 controls the drive wheels 10 of the transportation assist device 100 based on the control command value 82 output from the main control unit 21. That is, the drive control unit 22 calculates a command value (drive current 83) for the motor 11 of the corresponding drive wheel 10 based on the control command value 82, and outputs the obtained drive current 83 to the motor 11.

[0045] There are various control methods by the control device 20, and no particular limitation is imposed on them. As an example, Fig. 4 is a block diagram showing an example of the configuration of the control device 20 that controls the speed of the transport assist device 100.

[0046] In Figure 4, the control calculation unit 31 calculates the movement of the transport assistance device 100 according to the external force detection value 80 as a command value 81 for the movement speed of the transport assistance device 100. Note that the "movement speed of the transport assistance device 100" refers to the movement speed at the connection point (connection portion 120) between the traveling tool 110 and the transport assistance device 100 or at any point relative to the connection point. The movement speed of the transport assistance device 100 may also be referred to as the speed of the transport assistance device 100, but unless otherwise specified, they have the same meaning. Here, the command value 81 is a command value expressed in a Cartesian coordinate system, which is the speed of the transport assistance device 100.

[0047] The control calculation unit 31 in FIG. 4 receives an external force detection value 80 as an input and calculates a speed command value 81 using, for example, the command value calculation formula shown in Equation (1). ｃｍｄ = G ｆ F ｓ ... (1) where V ｃｍｄ represents the speed command value 81. ｆ represents the control gain of the assist control. ｓ represents the external force detection value 80.

[0048] The command value converter 34 converts the command value 81 expressed in the Cartesian coordinate system into a control command value 82 expressed in the wheel coordinate system. For example, the command value converter 34 calculates a control command value 82 for the angular velocity of each driving wheel 10 by multiplying the speed command value 81 expressed in the Cartesian coordinate system by the inverse matrix of the Jacobian matrix. In FIG. 4, J represents the Jacobian matrix, and J －１is the inverse matrix of the Jacobian matrix. Here, the wheel coordinate system is a rotating coordinate system with the drive shaft of the drive wheel 10 driven by the motor 11 as its origin. Furthermore, for example, in the case where the drive wheel 10 can also be driven in the steering direction (for example, in the case where the drive wheel described in JP 2020-024033 A is adopted), it also includes a rotating coordinate system with the steering shaft as its origin.

[0049] When the switching unit 32 switches the assist control to be enabled, it enables the calculation process of the assist control (calculation of the command value 81) by the control calculation unit 31. When the switching unit 32 switches the assist control to be disabled, it disables the calculation process of the assist control by the control calculation unit 31.

[0050] When switching to disable assist control, for example, the command value 81 of the control calculation unit 31 may be set to the current measurement value (current angular velocity value 85). This makes the control deviation and output value (drive current 83) in the drive control unit 22 very small, and it is possible to essentially disable the calculation process by the control calculation unit 31. Note that the control deviation may not become completely zero due to the influence of communication delays between the main control unit 21 and the drive control unit 22, etc.

[0051] The switching unit 32 may switch between enabling and disabling the assist control, for example, based on the detection of an external force and / or a change in the rotation angle of the drive wheels 10 while the operator is pushing the traveling implement 110. Alternatively, the switching unit 32 may switch between enabling and disabling the assist control through an operation input by the operator specifying whether to enable or disable the assist control. In this case, the transport assistance device 100 may include an operating device 102 (see FIG. 1 ) having one or more input units 103. The operating device 102 may be an HMI (Human Machine Interface) and may be, for example, an input device such as a mechanical switch or a joystick. The operating device 102 may also be a user interface realized by a touch panel display.

[0052] The smoothing processing unit 33 performs processing to suppress sudden changes in the movement speed of the transport assistance device 100 with respect to the movement of the transport assistance device 100 (i.e., the command value 81) in accordance with the external force detection value 80 detected by the external force detection unit 30.

[0053] 4, the drive control unit 22 calculates a command value for the motor 11 of the corresponding drive wheel 10 based on the angular velocity control command value 82 output from the main control unit 21 and the current value of the angle of each drive wheel 10. The drive control unit 22 includes a speed control unit 50 having a subtractor 50a and a PI control unit 50b, and a speed conversion unit 51.

[0054] The speed conversion unit 51 converts the current angle value (current angle value 84) obtained from the angle sensor 12 into the current angular velocity value (current angular velocity value 85). The speed control unit 50 subtracts the current angular velocity value 85 obtained by the speed conversion unit 51 from the angular velocity control command value 82 using the subtractor 50a to obtain the calculation result of the angular velocity deviation. The speed control unit 50 obtains a command value (drive current value) for the motor 11 by performing proportional-integral (PI) control using the PI control unit 50b based on the subtraction result (angular velocity deviation) by the subtractor 50a. The drive control unit 22 drives the motor 11 with a drive current 83 corresponding to the command value obtained by the PI control unit 50b.

[0055] 4, an example has been described in which the calculation result of the control calculation unit 31 is a speed command value, but it is also possible for the calculation result of the control calculation unit 31 to calculate a command value of another physical quantity such as acceleration, torque, or current, and for the drive control unit 22 to control these physical quantities, thereby performing assist control. Even in this case, the command value conversion unit 34 performs variable conversion from the Cartesian coordinate system to the wheel coordinate system.

[0056] <Smoothing Processing> Next, an example of the smoothing processing by the smoothing processing unit 33 will be described. Note that the smoothing processing is only required to output a control command value 82 that substantially suppresses changes in the movement speed of the transport assist device 100, and the smoothing method is not limited to the following example. First, when the assist control is disabled, a command value 81 that makes the speed deviation approximately zero is output, and when the assist control is enabled, a control gain G ｆAs an example, a case where the command value 81 is calculated by the formula (1) when is set to a certain value C (>0) will be described.

[0057] In the first example, the smoothing processing unit 33 smooths the change in the moving speed of the transport assist device 100 in response to the switching of the control calculation unit 31 from disabled to enabled. ｆ 5 shows the control gain G ｆ 1 is a graph showing an example of scheduling.

[0058] As shown in FIG. 5, when the switching unit 32 switches the assist control from disabled to enabled, the smoothing processing unit 33 adjusts the control gain G ｆ is scheduled to change continuously from 0 to the set value C, and the control gain G ｆ In the example of FIG. 5, the control gain G ｆ The control gain G is set to change in proportion to the current value of the moving speed of the transport assist device 100. ｆ The change in the control gain G is an example, and may be expressed by a function other than a linear function. ｆ may be a function of the time elapsed since the assist control was switched between enabled and disabled.

[0059] In a second example of the smoothing process, the smoothing processing unit 33 schedules the output amount of the calculation result in the control calculation unit 31 in response to switching of the control calculation unit 31 from disabled to enabled so as to smooth the change in the movement speed of the transport assist device 100. Figure 6 is a graph showing an example of scheduling of the output amount of the calculation result in the control calculation unit 31.

[0060] In the second example, even when the switching unit 32 switches the assist control from disabled to enabled, the control gain G ｆis fixed at a set value C. As shown in Fig. 6, the smoothing processing unit 33 schedules the output amount so that the output amount of the command value 81 transmitted from the control calculation unit 31 to the command value conversion unit 34 does not change suddenly. In other words, 100% of the calculation result of the control calculation unit 31 is not always output to the command value conversion unit 34, but the smoothing processing unit 33 schedules the output amount of the command value 81 so that it is 0% when the switching unit 32 switches the assist control from disabled to enabled, and then the output amount gradually increases from 0% to 100%.

[0061] 6, the change in the output amount of the command value 81 is set to change in proportion to the current value of the movement speed of the transport assist device 100. The change in the output amount of the command value 81 is just an example, and may be expressed by a function other than a linear function. With respect to the horizontal axis of the graph, the output amount of the command value 81 may be a function of the elapsed time from the time when the assist control is switched between enabled and disabled.

[0062] As a result of the scheduling, the control gain G ｆ When the output amount of the command value 81 (in the case of FIG. 5) reaches the set value C or the output amount of the command value 81 (in the case of FIG. 6) reaches 100%, the state coincides with the steady state when the assist control is enabled. In other words, the smoothing process is essentially completed.

[0063] <Explanation of Operation of Control Device> Fig. 7 is a flowchart illustrating the operation of the control device 20 of the transport assist device 100 according to the first embodiment. A control method for the transport assist device 100 according to the first embodiment shown in Figs. 1 to 6 will be described using Fig. 7. The control method for the transport assist device 100 according to the first embodiment is executed by the control device 20. Here, the control when switching the assist control of the transport assist device 100 from disabled to enabled will be described.

[0064] First, the main control unit 21 calculates the control command value 82 for each driving wheel 10 according to the external force input via the traveling implement 110 (steps S1 to S5).

[0065] Specifically, in step S1, the external force detection unit 30 detects an external force input to the transport assist device 100. The external force detection unit 30 outputs an external force detection value 80. Next, in step S2, the switching unit 32 determines whether the calculation of the command value 81 by the control calculation unit 31 has been switched to either enabled or disabled. Here, the switching unit 32 determines that the assist control (calculation of the command value 81) has been switched from disabled to enabled.

[0066] If it is determined that the assist control (calculation of the command value 81) has been switched from disabled to enabled (YES in step S2), the smoothing processing unit 33 performs processing to smooth changes in the movement speed of the transport assist device 100 in step S3. That is, the smoothing processing unit 33 performs processing to smooth the command value 81 so as to suppress changes in the movement speed of the transport assist device 100. If switching has not been performed (NO in step S2), the smoothing processing unit 33 does not perform the smoothing processing (step S3), and the processing proceeds to step S4.

[0067] In step S4, the control calculation unit 31 calculates a command value 81 that realizes the movement of the transport assist device 100 in accordance with the detected external force. If the smoothing process in step S3 has been performed (YES in step S2), the control calculation unit 31 performs calculations that reflect the results of the smoothing process. The results of the smoothing process are, for example, the control gain G ｆ or the scheduling of the output amount of the calculation result in FIG.

[0068] If the smoothing process in step S3 has not been performed (NO in step S2), the control calculation unit 31 performs calculations that reflect the enabled / disabled state of the assist control. When the assist control is enabled (in the case of a steady state after scheduling), the control calculation unit 31 uses a preset control gain G ｆ The control calculation unit 31 calculates the command value 81 using the set value C of the command value 81. When the assist control is disabled, the control calculation unit 31 essentially disables the calculation process of the command value 81. For example, the control calculation unit 31 outputs the command value 81 such that the speed deviation becomes approximately zero.

[0069] Next, in step S5, the command value conversion unit 34 converts the command value 81 calculated in the control calculation unit 31 into a control command value 82 for each of the driving wheels 10.

[0070] Next, each drive control unit 22 controls the drive wheels 10 of the transport assist device 100 based on the control command value 82 corresponding to the command value 81 (step S6).

[0071] Specifically, in step S6, the drive control unit 22 calculates a command value (drive current value) for the motor 11 of the corresponding drive wheel 10 based on the control command value 82 calculated by the main control unit 21. In the configuration example of FIG. 4 , the drive control unit 22 acquires the current angular velocity value 85 of the corresponding drive wheel 10 using the speed conversion unit 51. Next, the drive control unit 22 performs angular velocity control calculation using the speed control unit 50 based on the angular velocity control command value 82. That is, the subtractor 50a calculates the deviation between the angular velocity control command value 82 and the current angular velocity value 85, and the PI control unit 50b performs PI control based on the subtraction result by the subtractor 50a, thereby obtaining the drive command value (drive current value) for the motor 11.

[0072] Then, the drive control unit 22 drives the motor 11 with a drive current 83 according to the command value. As a result, the drive control unit 22 controls the angular velocity of the drive wheels 10 based on the control command value 82 for the angular velocity of the drive wheels 10.

[0073] 8 is a graph showing the change in speed of the traveling tool when the assist control is switched from disabled to enabled. The vertical axis of the graph shows the traveling speed of the traveling tool 110, and the horizontal axis shows the elapsed time. Note that the traveling tool 110 and the transport assistance device 100 are interconnected by a connection part 120, and the traveling speed of the traveling tool 110 and the traveling speed of the transport assistance device 100 can be considered to be the same.

[0074] In the example of Fig. 8, at time t0, the worker starts to apply an external force to the traveling tool 110, and in response, the traveling tool 110 starts to move. From time t0 to time t1, the assist control is disabled, and at time t1, the assist control is switched to enabled. From time t1 onwards, the assist control remains enabled.

[0075] <When smoothing processing is not performed: Comparative example> First, the behavior of the conveyance assist device 100 when smoothing processing is not performed (comparative example) will be described. Here, when assist control is disabled, a command value 81 is output that makes the speed deviation approximately 0 regardless of equation (1), and when assist control is enabled, the control gain G ｆ is set to a constant set value C (>0) and the command value 81 is calculated.

[0076] The speed change when smoothing processing is not performed is shown by graph V1 (solid line). When smoothing processing is not performed, when the assist control is switched from disabled to enabled at time t1, the control calculation unit 31 calculates the speed change according to equation (1) (control gain G ｆ = setting value C). As a result, the command value 81 output from the control calculation unit 31 changes suddenly at time t1, and the travel speed of the transport assistance device 100 (traveling tool 110) changes suddenly. In graph V1 of Fig. 8, the travel speed increases suddenly at time t1, then gradually decreases and converges to a constant value.

[0077] <When Smoothing Processing is Performed: First Embodiment> A graph V2 (dotted line) shows the speed change of the transport assist device 100 when smoothing processing according to the first embodiment is performed.

[0078] In the case of performing the smoothing process, when the assist control is switched from disabled to enabled at time t1, the change in the command value 81 of the control calculation unit 31 is smoothed by the smoothing processing unit 33. The graph V2 is a graph obtained by smoothing the change in the control gain G ｆ 8 shows an example of performing scheduling in which the control gain G in the formula (1) changes continuously from 0 to the set value C. That is, in the example of FIG. 8, the smoothing processing unit 33 performs scheduling in which the control gain G in the formula (1) changes continuously from 0 to the set value C in the scheduling period SP from time t1 to time t2. ｆ is continuously changed from 0 to the set value C, and at time t2, the control gain G ｆ reaches the set value C.

[0079] This suppresses sudden changes in the command value 81 output from the control calculation unit 31, resulting in a gradual change in the movement speed of the transport assistance device 100 (traveling tool 110). In graph V2 of Fig. 8, the change in movement speed at time t1 is equivalent to the change in movement speed up until just before time t1, and the movement speed gradually increases from time t1 to time t2. The gradual increase in movement speed from time t1 to time t2 is due to the scheduling of the smoothing processing unit 33.

[0080] After time t2, the control gain G ｆ This results in a steady state of assist control in which the moving speed is fixed to the set value C. As a result, in graph V2, the moving speed finally converges to a constant value, similar to graph V1.

[0081] In this way, the control device 20 of the transport assistance device 100 according to the first embodiment can realize drive control that suppresses changes in the travel speed of the transport assistance device 100 (traveling implement 110).

[0082] Second Embodiment Next, the configuration of a control device 20A of a transport assist device 100 according to a second embodiment will be described. Fig. 9 is a block diagram showing an example of the configuration of a control device 20A of a transport assist device 100 according to the second embodiment. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0083] In the first embodiment, the control calculation unit 31 calculates the control gain G ｆ Alternatively, an example has been shown in which a sudden change in the movement speed of the conveyance assist device 100 is suppressed by using scheduling of the output amount of the command value 81. In contrast to this, the second embodiment shows an example in which a sudden change in the movement speed is suppressed by low-pass filtering of the command value 81.

[0084] In the control device 20A of the transport assist device 100 according to the second embodiment, the smoothing processing unit 33 performs the smoothing process for a preset period of time. That is, the smoothing processing unit 33 enables the smoothing process when switching is performed by the switching unit 32, and disables the smoothing process after a certain period of time has elapsed.

[0085] In the second embodiment, the smoothing processing unit 33 executes low-pass filtering to attenuate high-frequency components of the calculation result in the control calculation unit 31 in response to switching of the control calculation unit 31 from disabled to enabled. The smoothing processing unit 33 enables the smoothing process when the control calculation unit 31 is switched from disabled to enabled, and disables the smoothing process after a certain time has elapsed. The high-frequency components of the calculation result mean a calculation result (command value 81) that changes greatly per unit time.

[0086] Therefore, when the assist control is enabled by the switching unit 32, the smoothing processing unit 33 executes low-pass filter processing for a certain period of time. The smoothing processing unit 33 receives the calculation result (command value 81) by the control calculation unit 31 as input, and outputs the command value 81 after the low-pass filter processing to the command value conversion unit 34. The certain period of time may be equivalent to the scheduling period SP shown in FIG. 8, for example.

[0087] The smoothing processing unit 33 disables the low-pass filter processing after a certain time has elapsed since the assist control was enabled. When the low-pass filter processing is disabled, the calculation result (command value 81) by the control calculation unit 31 is sent to the command value conversion unit 34 as is.

[0088] Consider, for example, a case in which the traveling tool 110 is accelerated to a desired travel speed (target value) by the worker. After the switching unit 32 switches the assist control from disabled to enabled, the smoothing processing unit 33 executes (enables) low-pass filtering until a certain time has elapsed. Therefore, if the calculation result by the control calculation unit 31 includes a sudden change, the smoothing processing unit 33 attenuates the amount of change and outputs the result to the command value conversion unit 34. As a result, if the calculation result by the control calculation unit 31 includes a sudden change, the speed increases more slowly than when low-pass filtering is not executed. After the certain time has elapsed, the deviation between the current speed value and the control command value 82 has become small due to the gradual speed increase, so even if low-pass filtering is disabled, no sudden speed change occurs.

[0089] This makes it possible to suppress a sudden change in the movement speed of the transport assist device 100 when the switching unit 32 switches the assist control from disabled to enabled.

[0090] Furthermore, the low-pass filter processing of the second embodiment outputs the low-frequency components contained in the calculation result by the control calculation unit 31 to the command value conversion unit 34 without substantially attenuating them. Therefore, when the change in the calculation result by the control calculation unit 31 at the timing when the assist control is switched from disabled to enabled is gradual (when the change in the applied external force is sufficiently small), the assist control is performed in which the calculation result by the control calculation unit 31 is directly reflected, thereby improving the responsiveness of the transport assist device 100.

[0091] The other configurations of the second embodiment are similar to those of the first embodiment.

[0092] Third Embodiment Next, the configuration of a control device 20B of a transport assist device 100 according to a third embodiment will be described. Fig. 10 is a block diagram showing an example of the configuration of a control device 20B of a transport assist device 100 according to the third embodiment. In the third embodiment, the same components as those in the first or second embodiment are denoted by the same reference numerals, and their description will be omitted.

[0093] In the third embodiment, the transport assist device 100 includes an operating device 102 (see FIG. 1 ). The transport assist device 100 can be driven in accordance with an operation amount input from the operating device 102, in addition to assisting drive in accordance with an external force.

[0094] The controller 102 and the control device 20B are connected by wired or wireless communication means so as to be able to exchange signals. Fig. 1 shows an example of wireless communication.

[0095] In the third embodiment, the main control unit 21 further includes an operation amount calculation unit 35 and a synthesis unit 36. In the third embodiment, when the assist control is switched between enabled and disabled, the switching unit 32 detects the occurrence of the switching and outputs the detection result to the smoothing processing unit 33 and the synthesis unit 36.

[0096] The operation amount calculation unit 35 detects the operation amount input from the operation device 102, and calculates a command value (operation command value 86) based on the obtained operation amount detection value. That is, the operation amount calculation unit 35 outputs the operation command value 86 for operating the transport assist device 100 in accordance with the detection value of the operation amount.

[0097] On the other hand, the control calculation unit 31 calculates an assist control calculation value 87 based on the external force detection value 80 detected by the external force detection unit 30. The assist control calculation value 87 is equivalent to the command value 81, which is the calculation result of the control calculation unit 31 in the first embodiment.

[0098] The combiner 36 combines the calculation result of the control calculator 31 and the calculation result of the operation amount calculator 35 to calculate a combined value 88. That is, the combiner 36 receives an operation command value 86 from the operation amount calculator 35 and an assist control calculation value 87 from the control calculator 31. The combiner 36 combines the operation command value 86 and the assist control calculation value 87 at a preset ratio. The command value converter 34 converts the combined value 88 output from the combiner 36 to generate a control command value 82 for each drive wheel 10.

[0099] In this way, the main control unit 21 of the third embodiment outputs a control command value 82 corresponding to a composite value 88 obtained by combining the calculation result of the control calculation unit 31 and the calculation result of the manipulated variable calculation unit 35 .

[0100] In the third embodiment, even when the assist control is disabled, the operation unit 102 may be able to drive the transport assist device 100. In this case, the operator does not need to continue applying an external force until the transport assist device 100 starts moving from a stationary state, which is expected to reduce the physical burden on the operator.

[0101] As an example, when the assist control is disabled, the combiner 36 combines the assist control calculation value 87 and the operation command value 86 in the ratio [assist control calculation value 87: operation command value 86=0%:100%]. When the assist control is enabled, the combiner 36 combines the assist control calculation value 87 and the operation command value 86 in the ratio [assist control calculation value 87: operation command value 86=50%:50%].

[0102] This allows the operator to drive the transport assistance device 100 not only by applying an external force to the transport assistance device 100 and the traveling implement 110 but also by using the operating device 102 .

[0103] When the assist control is enabled, the driving of the transport assist device 100 by the operator 102 may be disabled. That is, the composite ratio when the assist control is enabled may be [assist control calculation value 87: operation command value 86 = 100%:0%]. When the driving of the transport assist device 100 by the operator 102 is enabled, it is possible to use both the assist control and the driving by the operator 102. On the other hand, when the assist control is enabled, if the driving of the transport assist device 100 by the operator 102 is disabled, transport assistance is performed only by the assist control, as in the first and second embodiments.

[0104] <Smoothing Process> In the third embodiment, the smoothing processor 33 executes smoothing process in the synthesis value calculation by the synthesis unit 36 ​​.

[0105] A specific example of the smoothing process by the smoothing processor 33 is, for example, a means for smoothing the combination ratio of the assist control calculation value 87 and the operation command value 86 in the combination unit 36. When the assist control is switched from disabled to enabled, the smoothing processor 33 continuously changes the combination ratio of the assist control calculation value 87 from 0% to 50%. At this time, the combination ratio may be changed according to the current value of the movement speed of the transport assist device 100, or may be changed according to the elapsed time since the assist control was enabled.

[0106] If the combination ratio of the assist control calculation value 87 suddenly changes from 0% to 50% when the switching unit 32 switches the assist control from disabled to enabled, there is a possibility that the movement speed of the transport assist device 100 will suddenly change. Therefore, the smoothing processing unit 33 schedules the combination ratio of the assist control calculation value 87 so that the combination ratio gradually increases from 0% to 50%. As a result, a sudden increase in the control command value 82 immediately after the assist control is enabled is suppressed.

[0107] The smoothing process performed by the smoothing processor 33 is not limited to this.

[0108] The smoothing processing unit 33 may perform processing to suppress changes in the moving speed of the conveyance assist device 100 on a composite value 88, which is the calculation result of the combining unit 36, in response to switching of the control calculation unit 31 from disabled to enabled by the switching unit 32. For example, as in the second embodiment, there is a means for enabling low-pass filtering of the calculation result (combined value 88) by the combining unit 36 ​​for a certain period of time. In this case, the smoothing processing unit 33 receives the composite value 88 from the combining unit 36 ​​as input, and outputs the composite value 88 after the low-pass filtering to the command value conversion unit 34.

[0109] The other configurations of the third embodiment are similar to those of the first embodiment.

[0110] As described above, the control device 20 of the embodiment of the transport assistance device 100 comprises an external force detection unit 30 that detects an external force input to the transport assistance device 100 that assists the traveling of the traveling implement 110, a control calculation unit 31 that calculates a command value 81 that realizes the movement of the transport assistance device 100 in accordance with the external force detected by the external force detection unit 30, a switching unit 32 that switches the control calculation unit 31 between enabled and disabled, and a smoothing processing unit 33 that smooths changes in the movement speed of the transport assistance device 100 in response to the control calculation unit 31 being switched from disabled to enabled, a main control unit 21 that outputs a control command value 82 corresponding to the command value 81, and a drive control unit 22 that controls the drive wheels 10 of the transport assistance device 100 based on the control command value 82 output from the main control unit 21.

[0111] In addition, the control method for the transport assistance device 100 of the embodiment includes step S1 of detecting an external force input to the transport assistance device 100 that assists the traveling of the traveling implement 110, step S4 of calculating a command value 81 that realizes the movement of the transport assistance device 100 in accordance with the detected external force, step S2 of determining whether the calculation of the command value 81 has been switched to either valid or invalid, step S3 of performing a process of smoothing the command value 81 so as to suppress changes in the moving speed of the transport assistance device 100 when it is determined that the calculation of the command value 81 has been switched from invalid to valid, and step S6 of controlling the drive wheels 10 of the transport assistance device 100 based on a control command value 82 corresponding to the command value 81.

[0112] According to this, when the calculation of the command value 81 is switched from disabled to enabled, the smoothing process can suppress changes in the movement speed of the transport assist device 100. In other words, when the assist control is enabled, the control command value 82 for the drive wheels 10 is suppressed from increasing suddenly, and changes in the driving force generated by the transport assist device 100 are alleviated, thereby suppressing acceleration of the traveling implement 110 due to the driving force of the transport assist device 100. This suppresses sudden changes in speed when the assist control starts, making it possible to achieve a smooth switch when the assist control is enabled.

[0113] In the control device 20 of the transport assist device 100 according to the embodiment, the smoothing processing unit 33 smoothes the change in the moving speed of the transport assist device 100 in response to the switching of the control calculation unit 31 from disabled to enabled. ｆ , or the output amount of the calculation result in the control calculation unit 31 is scheduled.

[0114] According to this, the control gain G ｆ By scheduling the value of or the output amount of the calculation result, it is possible to reliably suppress a sudden change in the command value 81 itself calculated by the control calculation unit 31 or in the control command value 82 input to the drive control unit 22. Therefore, it is possible to reliably suppress a sudden change in speed when the assist control is enabled.

[0115] In addition, in the control device 20A of the transport assistance device 100 of the embodiment, the smoothing processing unit 33 enables the smoothing processing when the control calculation unit 31 is switched from disabled to enabled, and disables the smoothing processing after a certain period of time has elapsed.

[0116] This suppresses sudden speed changes when the assist control is enabled, while performing assist control without smoothing in the steady state after a certain time has elapsed since switching. Therefore, even when smoothing processing is performed, it is possible to suppress a decrease in the responsiveness of the transport assist device 100 in the steady state.

[0117] In the control device 20A of the transport assist device 100 according to the embodiment, the smoothing process is a low-pass filter process that attenuates high-frequency components of the calculation result in the control calculation unit 31.

[0118] According to this, even if the calculation result in the control calculation unit 31 changes suddenly at the timing when the control calculation unit 31 is switched to enabled (i.e., if the calculation result has high-frequency components), the change amount of the control command value 82 is attenuated by the low-pass filter processing. Therefore, when the assist control is enabled, it is possible to suppress a sudden change in the control command value 82 input to the drive control unit 22. Furthermore, when the calculation result in the control calculation unit 31 changes gradually (i.e., if the calculation result does not have high-frequency components), the calculation result does not attenuate or the attenuation is small, so it is possible to suppress a decrease in the responsiveness of the transport assist device 100 when the assist control is enabled.

[0119] In the control device 20B of the transport assist device 100 of this embodiment, the main control unit 21 further includes an operation amount calculation unit 35 that detects an operation amount input to the transport assist device 100 and calculates an operation command value 86 based on the detected value of the operation amount, and a combination unit 36 ​​that calculates a combined value 88 by combining the calculation result of the control calculation unit 31 (assist control calculation value 87) and the calculation result of the operation amount calculation unit 35 (operation command value 86), and outputs a control command value 82 corresponding to the combined value 88. A smoothing processing unit 33 performs smoothing processing in the calculation of the combined value by the combination unit 36.

[0120] This allows the user to operate the transport assist device 100 using the operation device 102, in addition to the assist control. Even in this case, by performing a smoothing process in the synthesis value calculation by the synthesis unit 36, it is possible to realize control that suppresses abrupt speed changes when the assist control is enabled, while responding to the user's operation input.

[0121] (Modifications) The control device for the transport auxiliary device and the control method for the transport auxiliary device may be freely combined from each embodiment, or any component of each embodiment may be modified, or any component of each embodiment may be omitted.

[0122] For example, in the embodiment, an example has been described in which the main control unit 21 calculates a command value for angular velocity and the drive control unit 22 performs speed control, but it is also possible to perform assist control by having the main control unit 21 calculate a command value for other physical quantities such as acceleration, torque, or current, and having the drive control unit 22 control these physical quantities.

[0123] It is also possible to perform assist control by having the main control unit 21 calculate a command value 81 for the angle of each drive wheel 10 and having the drive control unit 22 perform control based on the command value 81 for the angle.

[0124] For example, the control calculation unit 31 calculates a command value 81 for the position and attitude of the transportation assistance device 100 as a movement according to the external force detection value 80, and then calculates a control command value 82 for the angle of each drive wheel 10 from the command value 81 for the position and attitude by inverse kinematics calculation, and the drive control unit 22 controls the angle so that the control command value 82 matches the measured angle value (current angle value 84) obtained from the angle sensor 12, thereby controlling the position and attitude. Note that the position and attitude represent at least one of the position and attitude of the transportation assistance device 100.

[0125] REFERENCE SIGNS LIST 10 Drive wheel 11 Motor 12 Angle sensor 20 Control device 21 Main control unit 22 Drive control unit 30 External force detection unit 31 Control calculation unit 32 Switching unit 33 Smoothing processing unit 34 Command value conversion unit 35 Operation amount calculation unit 36 ​​Synthesis unit 40 Force sensor 50a Subtractor 50b PI control unit 50 Speed ​​control unit 51 Speed ​​conversion unit 80 External force detection value 81 Command value 82 Control command value 83 Drive current 84 Current angle value 85 Current angular velocity value 86 Operation command value (calculation result of operation amount calculation unit) 87 Assist control calculation value (calculation result of control calculation unit) 88 Synthesis value 100 Transport assist device 101 Housing 102 Operator 103 Input unit 110 Traveling implement 120 Connection unit 121 Connection unit main body 122 Mounting member

Claims

1. A control device for a transportation auxiliary device comprising: an external force detection unit that detects an external force input to a transportation auxiliary device that assists the travel of a traveling implement; a control calculation unit that calculates a command value that realizes movement of the transportation auxiliary device in accordance with the external force detected by the external force detection unit; a switching unit that switches the control calculation unit between enabled and disabled; a smoothing processing unit that smoothes changes in the movement speed of the transportation auxiliary device in response to switching of the control calculation unit from disabled to enabled; a main control unit that outputs a control command value corresponding to the command value; and a drive control unit that controls drive wheels of the transportation auxiliary device based on the control command value output from the main control unit.

2. The control device for a transport assistance device according to claim 1, wherein the smoothing processing unit schedules the control gain of the control calculation unit or the output amount of the calculation result in the control calculation unit so as to smooth out changes in the movement speed of the transport assistance device in response to switching of the control calculation unit from disabled to enabled.

3. The control device for a transport assistance device according to claim 1, wherein the smoothing processing unit enables the smoothing process when the control calculation unit is switched from disabled to enabled, and disables the smoothing process after a certain period of time has elapsed.

4. The control device for a transport auxiliary device according to claim 3, wherein the smoothing process is a low-pass filter process that attenuates high frequency components of the calculation result in the control calculation section.

5. A control device for a transport assist device as described in any one of claims 1 to 4, wherein the main control unit further comprises: an operation amount calculation unit that detects an operation amount input to the transport assist device and calculates a command value based on the detected value of the operation amount; and a synthesis unit that calculates a synthesis value by synthesizing a calculation result of the control calculation unit and a calculation result of the operation amount calculation unit, and outputs the control command value corresponding to the synthesis value; and the smoothing processing unit performs the smoothing process in the synthesis value calculation by the synthesis unit.

6. A control method for a transport auxiliary device, comprising: a step of detecting an external force input to a transport auxiliary device that assists the travel of a traveling implement; a step of calculating a command value that realizes movement of the transport auxiliary device in accordance with the detected external force; a step of determining whether the calculation of the command value has been switched to either valid or invalid; a step of smoothing the command value so as to suppress changes in the moving speed of the transport auxiliary device when it is determined that the calculation of the command value has been switched from invalid to valid; and a step of controlling drive wheels of the transport auxiliary device based on a control command value corresponding to the command value.

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