Conveying auxiliary device

Abstract

A conveyance assist device (1) is provided with: first and second Mecanum wheels (21R, 21L); a first motor and a second motor (22R, 22L) which are in drive connection with the first Mecanum wheel and the second Mecanum wheel (21R, 21L); first and second current sensors (SW1, SW2) that detect signals corresponding to the rotation states of the first and second Mecanum wheels (21R, 21L); a six-axis sensor (SW5) for detecting the rotation of the bed (10); and a controller (4). The controller (4) assists the movement of the bed (10) by a hand in the front-back direction when it is determined that the bed (10) is advancing but is not turned or retreating but is not turned, and assists the movement of the bed (10) by the hand in the front-back direction when it is determined that the bed (10) is turned while advancing or retreating but is turned while retreating, and assists the movement of the bed (10) by the hand in the front-back direction when it is determined that the bed (10) is turned while advancing or retreating. The controller (4) assists the hand in pushing the bed body (10) to move in the front-back direction and the transverse direction.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a conveyance assist device. BACKGROUND

[0002] For example, Patent Literature 1 discloses an assist propulsion system that uses Mecanum wheels for driving sections. The assist propulsion system includes a pair of Mecanum wheels coupled to a chassis, electric motors that drive the respective Mecanum wheels, and a control system that senses a change in rotational speed of the respective electric motors.

[0003] According to Patent Literature 1 described above, in a case where the chassis is moved in a prescribed direction, a force in the same direction as the movement direction is applied by an operator. If the respective Mecanum wheels rotate due to the applied force, a change in rotational speed accompanying the rotation is reported to the control system. The control system activates an electric rotation of the electric motor based on the report. The movement of the chassis is assisted by the electric rotation.

[0004] PRIOR ART DOCUMENTS PATENT LITERATURE Patent Literature 1: Japanese Published Patent Application No. 2016-525977 SUMMARY

[0005] PROBLEMS TO BE SOLVED BY THE INVENTION However, in a case where the structure described in Patent Literature 1 described above is applied to a bed with casters, a situation where the bed is turned is considered. In this case, since the bed is pushed and pressed in the front-rear direction while being turned, the bed is considered to be assisted in the front-rear direction.

[0006] However, the present inventors have repeatedly conducted intensive studies and as a result, have found that when assistance is provided only in the front-rear direction while turning, the turning radius becomes too small, and thus the front end or the rear end of the bed can interfere with a corner of an intersection, a T-shaped road, or the like. Such interference is not appropriate in terms of assisting the turning.

[0007] The present disclosure has been achieved in order to solve the above-described problems, and has an object to appropriately assist turning of a bed with casters.

[0008] MEANS FOR SOLVING THE PROBLEMS A first aspect of the present disclosure relates to a conveyance assist device for assisting movement of a wheeled bed body that is pushed by hand. The conveyance assist device includes first and second Mecanum wheels, first and second motors, a state sensor, a turning sensor, and a controller, the first and second Mecanum wheels are installed at a lower portion of the bed body and are in contact with a conveyance surface of the bed body, the first motor is drivingly coupled to the first Mecanum wheel, the second motor is drivingly coupled to the second Mecanum wheel, the state sensor detects a signal corresponding to a rotation state of the first and second Mecanum wheels, the turning sensor detects turning of the bed body about a rotation axis perpendicular to the conveyance surface, the controller controls the first and second motors, the controller performs determination of whether the bed body is advancing or retreating and determination of whether the bed body is turning, based on detection signals of the state sensor and the turning sensor, in a case where it is determined that the bed body is advancing and not turning or is retreating and not turning, the controller drives the first Mecanum wheel via the first motor and drives the second Mecanum wheel via the second motor in a manner to assist movement of the wheeled bed body pushed by hand in a front-rear direction, on the other hand, in a case where it is determined that the bed body is advancing while turning or is retreating while turning, the controller drives the first Mecanum wheel via the first motor and drives the second Mecanum wheel via the second motor in a manner to assist movement of the wheeled bed body pushed by hand in both the front-rear direction and a lateral direction, the lateral direction being orthogonal to the front-rear direction and extending along the conveyance surface.

[0009] According to the above-described first aspect, the controller assists movement of the wheeled bed body pushed by hand not only in the front-rear direction but also in the lateral direction. It is considered that a force is applied in the radius direction of the turn, that is, in the lateral direction of the bed body when the bed body turns. Therefore, by assisting the force in such a lateral direction, the bed body can be caused to slide in the lateral direction when turning. Thus, it is possible to increase the turning radius and suppress interference between the front or rear end portion of the bed body and a corner portion of the passage. Thus, it is possible to appropriately assist turning of the wheeled bed body.

[0010] Further, according to the second aspect of the present disclosure, the state sensor can also be constituted by a first current sensor that detects an induced current flowing through the first motor when the first Mecanum wheel rotates, and a second current sensor that detects an induced current flowing through the second motor when the second Mecanum wheel rotates, and the controller can estimate a longitudinal acceleration that indicates an acceleration of the first and second Mecanum wheels in the front-rear direction, and a lateral acceleration that indicates an acceleration of the first and second Mecanum wheels in the lateral direction, based on detection signals of the first and second current sensors, and the controller can perform first control in which command rotational speeds of the first and second motors are set in such a manner as to follow movement of the bed with the Mecanum wheeled bed pushed by hand, based on at least one of the longitudinal acceleration and the lateral acceleration, and in the case where it is determined that the bed is turning while advancing or turning while retreating, the controller can perform the first control based on the longitudinal acceleration with respect to the front-rear direction, and on the other hand, with respect to the lateral direction, the controller can perform the first control based on the lateral acceleration after adjusting the lateral acceleration in such a manner that the lateral acceleration is reduced at a prescribed rate higher than 0.

[0011] According to the second aspect described above, by detecting the induced current, it is possible to estimate the torque that is the cause of the induced current (torque that is intended to rotate the Mecanum wheel), and further, it is possible to estimate the acceleration that corresponds to the torque. By estimating the acceleration of each wheel, it is possible to estimate the direction in which the external force acts.

[0012] Further, with respect to the front-rear direction, assistance that follows movement of the bed with the Mecanum wheeled bed pushed by hand is performed, and on the other hand, with respect to the lateral direction, the first control based on the acceleration is performed after reducing the acceleration in that direction. Reducing the acceleration in the lateral direction is equivalent to estimating the external force acting in the same direction as being smaller than the actual external force. By estimating the external force to be smaller, with respect to the lateral direction, assistance that follows movement of the bed with the Mecanum wheeled bed pushed by hand is performed insufficiently. As a result, it is possible to suppress excessive slip (slip that exceeds the intention of the conveyor) in the lateral direction, and thereby to converge the turning radius within an appropriate range. Thus, it is possible to appropriately assist turning of the Mecanum wheeled bed.

[0013] Further, according to the third aspect of the present disclosure, the prescribed rate can be set so as to shift the turning center of the bed from a central position of the first and second Mecanum wheels to the front end side of the bed.

[0014] According to the above-described third aspect, by shifting the turning center of the bed body to the front end side, it is possible to realize an action such as turning the rear end side more greatly than the front end side when the bed body turns. By turning the rear end side greatly, it is possible to suppress interference between the portion of the rear end side and the corner of the passage. Thus, it is favorable to appropriately assist the turning of the bed body with casters.

[0015] Further, according to the fourth aspect of the present disclosure, it can also be that, in a case where it is determined that the bed body is advancing and not turning or is retreating and not turning, the controller executes the first control based on the longitudinal acceleration, and executes second control that increases the command rotational speed, in a case where it is determined that the bed body is turning while advancing or turning while retreating, the controller sequentially executes the first control and the second control with respect to the front-rear direction based on the longitudinal acceleration, and with respect to the lateral direction, the controller does not execute the second control on the basis of executing the first control based on the adjusted lateral acceleration.

[0016] According to the above-described fourth aspect, by executing the second control with respect to the front-rear direction, it is possible to not only follow the movement of the bed body with casters that is pushed by hand, but also to reduce the load on the conveyor in accordance with the amount by which the command rotational speed is increased. Thus, it is possible to improve the push feeling of the bed body in the front-rear direction, and thus to impart a moderate "assistance feeling" to the conveyor. On the other hand, with respect to the lateral direction, the second control is intentionally not executed. Thus, it is possible to suppress excessive slipping (slipping beyond the intention of the conveyor) in the lateral direction, and thus to converge the turning radius within an appropriate range. Thus, it is favorable to appropriately assist the turning of the bed body with casters.

[0017] Further, according to the fifth aspect of the present disclosure, it can also be that the first and second Mecanum wheels are arranged in line in the lateral direction, and each of the first and second Mecanum wheels has a wheel body that rotates about a rotation axis extending in the lateral direction, and a plurality of barrel rollers arranged along the outer periphery of the wheel body and each rotating about an inclined axis inclined with respect to both the front-rear direction and the lateral direction, and the inclined axis of the first Mecanum wheel is inclined so as to be symmetrical with the inclined axis of the second Mecanum wheel with the front-rear direction as a reference.

[0018] By being configured as in the above-described fifth aspect, it is possible to exert a pushing force such as causing the bed body to perform a turning action when the first and second Mecanum wheels are caused to rotate in opposite directions. By being configured as such, this is effective in appropriately assisting the turning of the bed body with casters.

[0019] Further, according to the sixth aspect of the present disclosure, it can also be that, in a case where it is determined that the bed body is advancing and not turning or is retreating and not turning, the controller sets the respective command rotational speeds in such a manner that both the first Mecanum wheel and the second Mecanum wheel are either forward-rotating or rearward-rotating, and, in making this setting, makes the absolute values of the command rotational speeds of the first Mecanum wheel and the second Mecanum wheel equal, and, in a case where it is determined that the bed body is advancing while turning or is retreating while turning, the controller sets the command rotational speeds in such a manner that the absolute values of the command rotational speeds are different between the first Mecanum wheel and the second Mecanum wheel.

[0020] According to the above-described sixth aspect, by making the absolute values of the command rotational speeds equal when moving forward and backward, more stable forward and backward movement can be achieved regardless of the orientation of the casters. On the other hand, by intentionally making the absolute values different when turning, turning along a desired trajectory can be achieved.

[0021] Effects of Invention As explained above, according to the present disclosure, turning of a bed body with casters can be appropriately assisted. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a side view illustrating the overall structure of the conveyance assistance device and the bed body with casters.

[0023] Figure 2 is a bottom view illustrating the overall structure of the conveyance assistance device and the bed body with casters.

[0024] Figure 3 is an elevation view illustrating the structure of the conveyance assistance device.

[0025] Figure 4 is a plan view illustrating the structure of the conveyance assistance device.

[0026] Figure 5 is a side view illustrating the structure of the conveyance assistance device.

[0027] Figure 6 is a block diagram illustrating the structure of the control system of the conveyance assistance device.

[0028] Figure 7 is a diagram for explaining the actions of the first Mecanum wheel and the second Mecanum wheel.

[0029] Figure 8 is a diagram for explaining the detection objects of the six-axis sensor.

[0030] Figure 9 is a flowchart illustrating the main processing performed by the controller.

[0031] Figure 10 is a flowchart illustrating a process related to determination of a moving direction.

[0032] Figure 11 is a control block diagram schematizing a structure of compliance control.

[0033] Figure 12 is a conceptual diagram for explaining a basic concept of compliance control.

[0034] Figure 13 is a graph illustrating a change in speed increase amount with respect to rotational speed.

[0035] Figure 14 is a graph illustrating a command rotational speed obtained by speed increase control.

[0036] Figure 15 is a flowchart illustrating compliance control and speed increase control.

[0037] Figure 16 is a flowchart illustrating control related to turning.

[0038] Figure 17 is a graph illustrating a trajectory of a bed body at the time of turning.

[0039] Figure 18 is a flowchart illustrating safety limit control.

[0040] Figure 19 is a graph showing a trajectory of a bed body in a conventional example and Figure 17 a corresponding graph. DETAILED DESCRIPTION

[0041] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.

[0042] Figure 1 is a side view illustrating an overall structure of the conveyance assist device 1 and the wheeled bed body 10, Figure 2 is a plan view illustrating an overall structure of the conveyance assist device 1 and the wheeled bed body 10.

[0043] In addition, Figure 3 is a perspective view illustrating a structure of the conveyance assist device 1, Figure 4 is a plan view illustrating a structure of the conveyance assist device 1, Figure 5 is a side view illustrating a structure of the conveyance assist device 1.

[0044] In addition, Figure 6 is a block diagram illustrating a structure of a control system of the conveyance assist device 1, Figure 7 is a graph for explaining an action of the first and second Mecanum wheels 21R and 21L.Figure 8 It is a diagram for explaining the detection object of the six-axis sensor SW5.

[0045] like Figure 1 and Figure 2 As shown, the transport assistance device 1 according to this embodiment is mounted on a bed 10 with casters (hereinafter referred to as a "bed"). This bed 10 includes a plurality of casters 14 with front wheels 14F and rear wheels 14B, and is used, for example, as a medical bed. The transport assistance device 1 assists manual movement of the bed 10.

[0046] Hereinafter, the longitudinal direction of the bed 10 , that is, the direction in which a person lies on the bed 10 , is referred to as the “front-rear direction” or “longitudinal direction”, the direction toward the toes along the front-rear direction is referred to as “front”, and the direction toward the pillow is referred to as “rear”.

[0047] Similarly, the short side direction of the bed 10, that is, the direction perpendicular to the front-back direction on the horizontal plane is defined as the "left-right direction" or "lateral direction", and the direction along the left-right direction is defined as the "right-left direction". Figure 1 Set the paper depth direction to "right" and move the Figure 1 The direction of the paper near the front is set to "left" (for details, refer to Figure 2 It should be noted that the "left-right direction" referred to here refers to the left-right direction when viewed from the rear toward the front. "Lateral movement" described below refers to movement along this left-right direction. Alternatively, the left-right direction (lateral direction) may be defined as a direction perpendicular to the front-back direction and extending along the conveying surface F (the ground surface on which the bed 10 travels).

[0048] The bed 10 is supported by a transporter 100. In the figure, one end side (eg, the rear end side) of the bed 10 in the front-rear direction is supported. The transport assist device 1 operates to assist the transporter 100 in manually pushing and moving the bed 10 supported by the transporter 100.

[0049] like Figure 1 As shown, the bed 10 includes a bed body 11 that supports a mattress (not shown); a bed frame 12 that supports the bed body 11 from below; a lifting unit 13 that raises and lowers the bed body 11 relative to the bed frame 12; and a plurality of (four in the figure) casters 14 arranged on the lower surface of the bed 10. When used as a medical bed, the bed 10 has a mass of, for example, 60 kg or more and 300 kg or less.

[0050] Here, the bed body 11 has: a headboard 11h arranged on the rear end side of the bed 10; a footboard 11f arranged on the front end side opposite to the rear end side in the front-rear direction; and side rails 11s arranged on the left and right sides of the bed 10.

[0051] In order to move the bed body 10 by hand, the bed head board 11h is supported from the rear side by a conveyance person 100. The bed head board 11h functions as a support portion to which a force is applied by the conveyance person 100. A handle, a grip, or the like can be installed on the bed head board 11h or integrated with the bed head board 11h, and the handle, the grip, or the like can be used as the support portion. The bed foot board 11f, the side rail 11s, or the like can be supported.

[0052] In addition, as shown in FIG. 1, the bed frame 12 is configured in a rectangular frame shape, and is composed of a front bed frame 12F, a right bed frame 12R, a left bed frame 12L, and a rear bed frame 12B. Figure 2

[0053] Here, the front bed frame 12F is disposed at the front side of the bed body 10 and extends in the left-right direction. The right bed frame 12R is disposed at the right side of the bed body 10 and extends in the front-rear direction. The left bed frame 12L is disposed at the left side of the bed body 10 and extends in the front-rear direction. The rear bed frame 12B is disposed at the rear side of the bed body 10 and extends in the left-right direction.

[0054] In addition, as shown in FIG. 1, the bed frame 12 is configured in a rectangular frame shape, and is composed of a front bed frame 12F, a right bed frame 12R, a left bed frame 12L, and a rear bed frame 12B. Figure 1 Figure 2 In addition, as shown in FIG. 1, the bed frame 12 is configured in a rectangular frame shape, and is composed of a front bed frame 12F, a right bed frame 12R, a left bed frame 12L, and a rear bed frame 12B.

[0055] Each caster 14 is a so-called free wheel, and has a mounting portion 14a fixed to the lower surface of the bed body 10, a yoke portion 14b that can be revolved with respect to the mounting portion 14a about a revolution axis Oc, and a wheel 14c that is supported by the yoke portion 14b so as to be rotatable. The revolution axis Oc of each yoke portion 14b extends in the up-down direction (the height direction of the bed body 10). The rotation axis of each wheel 14c extends in the horizontal plane. By revolving the yoke portion 14b with respect to the mounting portion 14a, the rotation axis is inclined with respect to the left-right direction.

[0056] Further, the conveyance assisting device 1 is disposed in a manner of being erected at a position in the front-rear direction at the middle of the right bed frame 12R and at a position in the front-rear direction at the middle of the left bed frame 12L. The conveyance assisting device 1 is disposed between the front wheels 14F and the rear wheels 14B in the front-rear direction and at the center of the bed body 10 in the left-right direction.

[0057] As shown in FIG. 1, the conveyance assisting device 1 is disposed in a manner of being erected at a position in the front-rear direction at the middle of the right bed frame 12R and at a position in the front-rear direction at the middle of the left bed frame 12L. The conveyance assisting device 1 is disposed between the front wheels 14F and the rear wheels 14B in the front-rear direction and at the center of the bed body 10 in the left-right direction. Figure 1-6 ​​As shown, the conveyance assisting device 1 includes the housing box 6, the mount 7, the first and second Mecanum wheels 21R and 21L, the first and second electric motors 22R and 22L, the controller 4, the first and second current sensors SW1 and SW2 as state sensors, the first and second rotation sensors SW3 and SW4, and the six-axis sensor SW5 as a turning sensor (the first and second electric motors 22R and 22L and the sensors SW1 to SW5 are only illustrated in Figure 6 the following). Hereinafter, the first Mecanum wheel 21R is located on the right side and the second Mecanum wheel 21L is located on the left side among the first and second Mecanum wheels 21R and 21L.

[0058] The controller 4 and the six-axis sensor SW5 among these elements are housed in the housing box 6, and the mount 7, the first and second Mecanum wheels 21R and 21L, the first and second electric motors 22R and 22L, the first and second current sensors SW1 and SW2, and the first and second rotation sensors SW3 and SW4 are arranged outside the housing box 6.

[0059] The housing box 6 houses the controller 4 as described above. The housing box 6 is arranged between the first and second Mecanum wheels 21R and 21L in the left-right direction.

[0060] The housing box 6 is mounted on the mount 7 together with the first and second Mecanum wheels 21R and 21L, and is mounted on the lower portion of the bed body 10 via the mount 7. The mount 7 is detachable with respect to the lower portion of the bed body 10. That is, the conveyance assisting device 1 according to the present embodiment is attachable to the bed body 10, and the conveyance assisting device 1 can be detached as needed.

[0061] In detail, as shown in Figure 2-5 the mount 7 according to the present embodiment has the front and rear rail members 71f and 71b, and the first and second arm members 72R and 72L that rotatably support the first and second Mecanum wheels 21R and 21L, respectively.

[0062] Here, the front and rear rail members 71f and 71b are arranged apart from each other in the front-rear direction and are respectively erected on the front-rear direction central portions of the right and left bed frames 12R and 12L. The front and rear rail members 71f and 71b are detachable with respect to the right and left bed frames 12R and 12L. The first and second Mecanum wheels 21R and 21L and the housing box 6 are arranged between the front and rear rail members 71f and 71b in the front-rear direction.

[0063] On the other hand, inFigure 3 and Figure 4 The first arm member 72R on the right side is supported so as to be swingable by the rear rail member 71b. The front end portion of the first arm member 72R supports the first Mecanum wheel 21R so as to be rotatable. In addition, the first arm member 72R is arranged between the first Mecanum wheel 21R and the housing box 6 in the left-right direction.

[0064] In addition, one end portion of the first extension spring 75R is hooked at the upper end portion of the first arm member 72R. The other end portion of the first extension spring 75R is hooked at the first bracket 76R fixed to the front rail member 71f.

[0065] Also, as with the first arm member 72R, the second arm member 72L is supported so as to be swingable by the rear rail member 71b. Figure 3 and Figure 4 The front end portion of the second arm member 72L supports the second Mecanum wheel 21L so as to be rotatable. In addition, the second arm member 72L is arranged between the second Mecanum wheel 21L and the housing box 6 in the left-right direction.

[0066] In addition, one end portion of the second extension spring 75L is hooked at the upper end portion of the second arm member 72L. The other end portion of the second extension spring 75L is hooked at the second bracket 76L fixed to the front rail member 71f (see also Figure 5 ).

[0067] As shown in Figure 1-2 , the first Mecanum wheel 21R and the second Mecanum wheel 21L are installed at the lower portion (bottom portion) of the bed body 10. The first Mecanum wheel 21R and the second Mecanum wheel 21L are in contact with the conveyance face F of the bed body 10. The conveyance face F is shown only in Figure 1 . In addition, the first Mecanum wheel 21R and the second Mecanum wheel 21L are arranged at the rear side of the front wheels 14F and at the front side of the rear wheels 14B. In the case of the present embodiment, as shown in Figure 2 , the first Mecanum wheel 21R and the second Mecanum wheel 21L are arranged so as to be aligned in the left-right direction which is the short side direction.

[0068] In detail, as shown in Figure 3-5 , the first Mecanum wheel 21R has a first wheel body 211R which rotates around a first rotation axis Oy1, and a plurality of first barrel-shaped rollers 212R which are arranged along the outer periphery of the first wheel body 211R and which respectively rotate around first inclined axes Or which are inclined with respect to the first rotation axis Oy1.

[0069] On the other hand, the second Mecanum wheel 21L has: a second wheel body 211L that rotates around a second rotation axis Oy2; and a plurality of second barrel-shaped rollers 212L that are arranged along the outer periphery of the second wheel body 211L and rotate around a second inclined axis Ol that is inclined in a direction different from the first inclined axis Or relative to the second rotation axis Oy2.

[0070] Here, both the first rotation axis Oy1 and the second rotation axis Oy2 extend in the left-right direction. Figure 4 In other words, when a plane extending in the up-down direction and the front-back direction is set as a mirror plane, the first tilt axis Or and the second tilt axis Ol extend in a mirror-symmetrical manner with respect to the mirror plane.

[0071] Moreover, in Figure 4 When viewed from above (in a plan view), the first tilt axis Or and the second tilt axis Ol extend from the inside in the left-right direction toward the outside (from the center in the left-right direction toward the right or left side) as they approach the front side from the rear side along the front-rear direction.

[0072] Specifically, the first tilt axis Or extends from the center of the left-right direction toward the right as it approaches the front side from the rear side in the front-rear direction. Meanwhile, the second tilt axis Ol extends from the center of the left-right direction toward the left as it approaches the front side from the rear side in the front-rear direction.

[0073] More specifically, the inclination angle θr of the first inclination axis Or relative to the first rotation axis Oy1 is set to be Similarly, the inclination angle θ1 of the second inclination axis O1 relative to the second rotation axis Oy2 is also set to be It should be noted that the tilt direction and tilt angle of each barrel roller 212R, 212L are not limited to these examples. For example, the arrangement of the entire conveying auxiliary device 1 can also be changed from Figure 2 The illustrated state is changed to a state rotated by a predetermined angle around the z-axis extending in the vertical direction.

[0074] In addition, as described above, the first Mecanum wheel 21R and the second Mecanum wheel 21L are connected by Figure 3 The front rail member 71f and the rear rail member 71b shown in FIG. 1 are connected to each other. Therefore, the first Mecanum wheel 21R and the second Mecanum wheel 21L move integrally in the front-back direction and the left-right direction, or integrally rotate around a rotation axis perpendicular to the horizontal plane.

[0075] The first motor 22R and the second motor 22L are drivingly coupled to the first Mecanum wheel 21R and the second Mecanum wheel 21L, respectively. Specifically, the first motor 22R and the second motor 22L are configured as so-called three-phase DC brushless motors. Both the first motor 22R and the second motor 22L are electrically connected to the controller 4 and controlled by the controller 4.

[0076] When the first motor 22R and the second motor 22L are each rotated, motor currents corresponding to torque loads are supplied to the first motor 22R and the second motor 22L. The rotation speed, forward rotation, and reverse rotation of the first motor 22R and the second motor 22L can be switched by the motor currents.

[0077] Also, the first motor 22R is coupled to the first Mecanum wheel 21R in a manner that enables transmission of driving force (torque) to the first Mecanum wheel 21R. The second motor 22L is coupled to the second Mecanum wheel 21L in a manner that enables transmission of driving force (torque) to the second Mecanum wheel 21L.

[0078] The first motor 22R is rotated, whereby driving force is transmitted downward, and the first Mecanum wheel 21R is rotated. Similarly, the second motor 22L is rotated, whereby driving force is transmitted downward, and the second Mecanum wheel 21L is rotated.

[0079] In the present embodiment, the first Mecanum wheel 21R is caused to turn forward by forward rotation of the first motor 22R and is caused to turn backward by reverse rotation of the first motor 22R. Similarly, in the present embodiment, the second Mecanum wheel 21L is caused to turn forward by forward rotation of the second motor 22L and is caused to turn backward by reverse rotation of the second motor 22L.

[0080] Note that the first motor 22R is built into the first Mecanum wheel 21R, and the second motor 22L is built into the second Mecanum wheel 21L. By building the first motor 22R and the second motor 22L in this way, simplification and compactness of the entire conveyance assisting device 1 can be achieved.

[0081] In addition, the first current sensor SW1 and the second current sensor SW2, which are state sensors, detect signals corresponding to the rotation states of the first Mecanum wheel 22R and the second Mecanum wheel 22L.

[0082] Specifically, the first current sensor SW1 detects an induced current flowing through the first motor 22R when the first Mecanum wheel 21R rotates. That is, if the first Mecanum wheel 21R rotates due to an external force, the rotor rotates relative to the stator in the first motor 22R, and an induced current is generated. The induced current detected by the first current sensor SW1 corresponds to a q-axis current.

[0083] Here, the magnitude of the induced current is proportional to the torque acting on the first Mecanum wheel 21R when the first Mecanum wheel 21R rotates due to an external force. The magnitude of the torque is associated with the magnitude of the external force applied to the bed 10, and further associated with the amount of change in the speed of the bed 10 due to the external force. In addition, the sign of the induced current is associated with the direction of rotation of the first Mecanum wheel 21R when the first Mecanum wheel 21R rotates due to an external force. The sign of the induced current is opposite to the sign of the motor current that flows when the first motor 22R is driven.

[0084] The second current sensor SW2 detects an induced current flowing through the second motor 22L when the second Mecanum wheel 21L rotates. That is, if the second Mecanum wheel 21L rotates due to an external force, the rotor rotates relative to the stator in the second motor 22L, and an induced current is generated. The induced current detected by the second current sensor SW2 corresponds to a q-axis current.

[0085] Here, the magnitude of the induced current is proportional to the torque acting on the second Mecanum wheel 21L when the second Mecanum wheel 21L rotates due to an external force. The magnitude of the torque is associated with the magnitude of the external force applied to the bed 10, and further associated with the amount of change in the speed of the bed 10 due to the external force. In addition, the sign of the induced current is associated with the direction of rotation of the second Mecanum wheel 21L when the second Mecanum wheel 21L rotates due to an external force. The sign of the induced current is opposite to the sign of the motor current that flows when the second motor 22L is driven.

[0086] For example, in a case where the first Mecanum wheel 21R is forward-rotated while the second Mecanum wheel 21L is backward-rotated due to an external force, the first current sensor SW1 detects an induced current of the same sign as when the first motor 22R is reversed. The second current sensor SW2 detects an induced current of the same sign as when the second motor 22L is forward-rotated.

[0087] As described in detail below, the controller 4 according to the present embodiment is configured to perform assistance in the positive direction, i.e., the direction in which the external force acts, by feeding back the torque corresponding to the induced current, more specifically, the command rotational speed at which the first motor 22R and the second motor 22L rotate corresponding to the torque.

[0088] Further, the first rotation sensor SW3 and the second rotation sensor SW4 detect the rotation speeds of the first motor 22R and the second motor 22L, respectively. Specifically, the first rotation sensor SW3 and the second rotation sensor SW4 according to the present embodiment are each configured by an encoder. The first rotation sensor SW3 as an encoder detects the rotation speed and the rotation angle of the first motor 22R, and similarly, the second rotation sensor SW4 as an encoder detects the rotation speed and the rotation angle of the second motor 22L.

[0089] Further, as shown in FIG. 2, a six-axis sensor SW5 as a roll sensor detects the roll of the bed body 10 around the rotation axis (z-axis) perpendicular to the conveyance surface F. Figure 8 Figure 8 Further, as shown in FIG. 2, a six-axis sensor SW5 as a roll sensor detects the roll of the bed body 10 around the rotation axis (z-axis) perpendicular to the conveyance surface F.

[0090] Further, as shown in FIG. 2, a six-axis sensor SW5 as a roll sensor detects the roll of the bed body 10 around the rotation axis (z-axis) perpendicular to the conveyance surface F.

[0091] The controller 4 controls the first motor 22R and the second motor 22L on the basis of the electric signals input from the various sensors SW1 to SW5. The controller 4 has a CPU, a memory, and an input / output bus, and is configured by, for example, a control board.

[0092] Specifically, the controller 4 according to the present embodiment sets the command rotation speed of each of the first motor 22R and the second motor 22L on the basis of the detection signals input from the various sensors SW1 to SW5. The controller 4 inputs a motor current corresponding to the set command rotation speed to each of the first motor 22R and the second motor 22L. Thus, each of the first motor 22R and the second motor 22L rotates at the command rotation speed set by the controller 4.

[0093] At this time, the first Mecanum wheel 21R rotates at the same rotation speed as the first motor 22R, and the second Mecanum wheel 21L rotates at the same rotation speed as the second motor 22L. That is, setting the command rotation speed of each of the first motor 22R and the second motor 22L is equivalent to setting the command rotation speed of each of the first Mecanum wheel 21R and the second Mecanum wheel 21L.

[0094] ​Further, by changing the signs of the respective command rotational speeds, the rotational directions of the first motor 22R and the second motor 22L can be individually changed. By changing the rotational directions of the respective motors 22R, 22L, the corresponding Mecanum wheels 21R, 21L can be switched between forward rotation and reverse rotation.

[0095] In the present embodiment, if the first Mecanum wheel 21R on the right side is caused to rotate forward, the conveyance assisting device 1 and the bed 10 can be given a thrust to the left oblique front (refer to arrow A of Figure 7 11 ). On the other hand, if the second Mecanum wheel 21L on the left side is caused to rotate forward, the conveyance assisting device 1 can give a thrust to the bed 10 to the right oblique front (refer to arrow A of Figure 7 12 ).

[0096] Therefore, for example as shown in the upper left of Figure 7 , if both the first Mecanum wheel 21R and the second Mecanum wheel 21L are caused to rotate forward, the thrust to the left direction given by causing the first Mecanum wheel 21R to rotate forward and the thrust to the right direction given by causing the second Mecanum wheel 21L to rotate forward cancel each other out, and a thrust to the front direction can be given to the bed in the entire conveyance assisting device 1. With this thrust, the bed 10 can be assisted to move in the front direction.

[0097] Likewise, if the first Mecanum wheel 21R on the right side is caused to rotate rearward, the conveyance assisting device 1 and the bed 10 can be given a thrust to the right oblique rear (refer to arrow A of Figure 7 21 ). On the other hand, if the second Mecanum wheel 21L on the left side is caused to rotate rearward, the conveyance assisting device 1 can give a thrust to the bed 10 to the left oblique rear (refer to arrow A of Figure 7 22 ).

[0098] Therefore, for example as shown in the upper right of Figure 7 , if both the first Mecanum wheel 21R and the second Mecanum wheel 21L are caused to rotate rearward, the thrust to the right direction given by causing the first Mecanum wheel 21R to rotate rearward and the thrust to the left direction given by causing the second Mecanum wheel 21L to rotate rearward cancel each other out, and a thrust to the rear direction can be given to the bed in the entire conveyance assisting device 1. With this thrust, the bed 10 can be assisted to move in the rear direction.

[0099] On the other hand, if one of the first Mecanum wheel 21R and the second Mecanum wheel 21L is caused to rotate forward and the other is caused to rotate rearward, the conveyance assisting device 1 gives a thrust to the bed 10 to the left direction or the right direction.

[0100] In Figure 7 ​​​​In the example shown in the lower left figure of FIG, the first Mecanum wheel 21R is rotated backward and the second Mecanum wheel 21L is rotated forward, thereby applying a rightward thrust to the bed 10.

[0101] Furthermore, if only one of the first Mecanum wheel 21R and the second Mecanum wheel 21L is rotated forward or backward, the transport assistance device 1 applies a thrust in an oblique direction to the bed 10 .

[0102] exist Figure 7 In the example shown in the lower right figure, by rotating only the second Mecanum wheel 21L forward, the bed 10 can be moved diagonally to the right front. On the other hand, when only the first Mecanum wheel 21R is rotated forward, the bed 10 can be assisted in moving diagonally to the left front (not shown).

[0103] Furthermore, the transport assisting device 1 is configured to assist the transporter 100 in transporting the bed 10 by operating the first motor 22R and the second motor 22L based on detection signals from the various sensors SW1 to SW5 , thereby assisting the transporter 100 in transporting the bed 10 by applying the thrust as described above.

[0104] In order to achieve such assistance, the controller 4 involved in this embodiment determines the direction in which the external force is exerted (hereinafter also referred to as the "action direction") based on the detection signals of various sensors SW1 to SW5, and operates the first motor 22R and the second motor 22L in a manner that exerts thrust along the action direction.

[0105] For example, when the headboard 11h is pushed from the rear to the front and it is determined that the external force is acting from the rear to the front, the controller 4 rotates both the first motor 22R and the second motor 22L forward, thereby rotating both the first Mecanum wheel 21R and the second Mecanum wheel 21L forward. Figure 7 Proceed as shown in the upper left picture.

[0106] Furthermore, the first and second Mecanum wheels 21R and 21L are allowed to rotate forward and backward even when the corresponding motors 22R and 22L are not driven. This prevents the bed 10 from shaking when moved manually, thereby stabilizing the transport of the bed 10.

[0107] Below, use Figure 9 etc. will describe the assistance performed by the controller 4 in detail.

[0108] Here, Figure 9 is a flowchart illustrating main processing performed by the controller 4 . Figure 10 This is a flowchart illustrating a process related to determination of a moving direction. Figure 11 This is a control block diagram that schematically illustrates the structure of compliant control.Figure 12 is a conceptual diagram for explaining the basic concept of compliance control. Figure 13 is a graph illustrating a change in the amount of speed increase with respect to the rotational speed. Figure 14 is a graph illustrating the command rotational speed obtained by the speed increase control. Figure 15 is a flowchart illustrating the compliance control and the speed increase control.

[0109] In addition, Figure 16 is a flowchart illustrating the control related to the turning. Figure 17 is a graph illustrating the trajectory of the bed 10 at the time of turning. Figure 18 is a flowchart illustrating the safety limit control.

[0110] First, in Figure 9 Step S1 of the controller 4, the detection signals of the above-described five sensors SW1 to SW5 are read in.

[0111] In the following step S2, the controller 4 estimates the acceleration of the first Mecanum wheel 21R based on the detection signal of the first current sensor SW1, and estimates the acceleration of the second Mecanum wheel 21L based on the detection signal of the second current sensor SW2.

[0112] Hereinafter, the acceleration of the first Mecanum wheel 21R will be referred to as "first acceleration", and the acceleration of the second Mecanum wheel 21L will be referred to as "second acceleration". Both the first acceleration and the second acceleration are the time derivative of the translational speed, that is, the so-called tangential acceleration.

[0113] The magnitude of the induced current detected by the first current sensor SW1 and the second current sensor SW2 respectively is proportional to the torque (particularly, the torque caused by the reaction force) acting on the first Mecanum wheel 21R and the second Mecanum wheel 21L at the time of rotation of these wheels. The controller 4 estimates the first torque acting on the first Mecanum wheel 21R and the second torque acting on the second Mecanum wheel 21L individually based on such proportional relationship. At this time, as a proportional coefficient for converting from the induced current to the torque, a proportional coefficient stored in advance in the controller 4 can be used.

[0114] The controller 4 according to the present embodiment assists the movement of the bed 10 by driving the first motor 22R and the second motor 22L in a manner to overcome the reaction force corresponding to the first torque and the second torque.

[0115] In order to achieve such assistance, the controller 4 estimates the first acceleration corresponding to the first torque and the second acceleration corresponding to the second torque based on the following equations (1) and (2).

[0116] a r = (-1) · Tr / (R·m)……(1) a l =(-1)·T l / (R·m)……(2) In the above formulas (1) and (2), T r [Nm] is the first torque, T l [Nm] is the second torque. r [m / s 2 ] is the first acceleration corresponding to the first torque, a l [m / s 2 ] is the second acceleration corresponding to the second torque.

[0117] Furthermore, R [m] represents the tire radius of each of the first and second Mecanum wheels 21R, 21L, and m [kg] represents the mass of each of the first and second Mecanum wheels 21R, 21L. In this embodiment, the tire radius and mass of the first and second Mecanum wheels 21R, 21L are equal.

[0118] In the next step S3 , the controller 4 estimates the translational accelerations of the first Mecanum wheel 21R and the second Mecanum wheel 21L based on the detection signals of the first current sensor SW1 and the second current sensor SW2 .

[0119] Specifically, the controller 4 uses the first acceleration a estimated based on the detection signals of the first current sensor SW1 and the second current sensor SW2. r and the second acceleration a l The longitudinal acceleration, which indicates the translational acceleration of the first Mecanum wheel 21R and the second Mecanum wheel 21L in the front-to-back direction, and the lateral acceleration, which indicates the translational acceleration of the first Mecanum wheel 21R and the second Mecanum wheel 21L in the lateral direction, are estimated.

[0120] In more detail, Figure 3-5 When the first Mecanum wheel 21R and the second Mecanum wheel 21L are configured in this manner, the controller 4 adjusts the first acceleration a r and the second acceleration a l The longitudinal acceleration is estimated by adding the first acceleration a r With the second acceleration a l The details of these calculations are shown in the following equations (3) and (4).

[0121] a x =(a r +a l ) / 2……(3) a y =(a r -a l ) / 2……(4) In the above formula (3) and formula (4), a x [m / s 2 ] is the longitudinal acceleration, and a y [m / s 2 ] is the lateral acceleration. The sign of formula (3) is defined as follows: the front is positive, and the rear is negative. The signs of the front and the rear can also be reversed. Similarly, the sign of formula (4) is defined as follows: the left is positive, and the right is negative. The signs of the left and the right can also be reversed.

[0122] Note that, with respect to the rotational speed of each of the first motor 22R and the second motor 22L (i.e., the rotational speed of each of the first Mecanum wheel 21R and the second Mecanum wheel 21L), a relationship such as formula (3) and formula (4) also holds.

[0123] Here, let r r [rpm] be the rotational speed of the first motor 22R in the front-rear direction (hereinafter, also referred to as the “first rotational speed”), and let r l [rpm] be the rotational speed of the second motor 22L in the front-rear direction (hereinafter, also referred to as the “second rotational speed”). The first rotational speed r r is the rotational speed detected by the first rotation sensor SW3, and the second rotational speed r l is the rotational speed detected by the second rotation sensor SW4.

[0124] Also, let r x [rpm] be the rotational speed of the first motor 22R and the second motor 22L as a whole in the front-rear direction (hereinafter, also referred to as the “longitudinal rotational speed”), and let r y [rpm] be the rotational speed of the first motor 22R and the second motor 22L as a whole in the left-right direction (hereinafter, also referred to as the “lateral rotational speed”). In the case where the first Mecanum wheel 21R and the second Mecanum wheel 21L are configured and arranged as in the present embodiment, the following formula (5) and formula (6) hold.

[0125] r x =(r r +r l ) / 2……(5) r y =(r r -r l ) / 2……(6) The above formula (5) and formula (6) can be changed into the following formula (7) and formula (8). As shown in the following formula (7) and formula (8), by setting r x and r y , r r and r l can be uniquely determined.

[0126] r r = r x + r y … (7) r l = r x - r y … (8) In addition, by multiplying both sides of the above formula (7) and formula (8) by a constant (= πR / 30) depending on the tire radius R and the circular constant, the same relationship with respect to the speed can also be obtained. That is, let v r [m / s] be the speed of the first Mecanum wheel 21R in the front-rear direction, let v l [m / s] be the speed of the second Mecanum wheel 21L in the front-rear direction. Also, let v x [m / s] be the speed of the entire first Mecanum wheel 21R and second Mecanum wheel 21L in the front-rear direction (hereinafter, also referred to as "longitudinal speed"), and let v y [m / s] be the speed of the entire first Mecanum wheel 21R and second Mecanum wheel 21L in the left-right direction (hereinafter, also referred to as "lateral speed"). Also, in the case where the first Mecanum wheel 21R and second Mecanum wheel 21L are configured and arranged as in the present embodiment, the following formula (9) and formula (10) hold.

[0127] Note that the "speed" in this case shows the translational speed (tangential speed) of an object that is performing angular motion.

[0128] v x = (v r + v l ) / 2 … (9) v y = (v r - v l ) / 2 … (10) The above formula (9) and formula (10) can be changed into, for example, the following formula (11) and formula (12). As shown in the following formula (11) and formula (12), by setting v x and v y , v r and v l can be uniquely determined.

[0129] vr =v x +v y …… (11) v l =v x -v y …… (12) In addition, by utilizing the relationship between the equations, for example, when determining the longitudinal velocity v x The command value and / or lateral speed v y When the command values ​​are set, the longitudinal speed r required to achieve these command values ​​can be uniquely determined. r and lateral rotation speed r l , or determine the longitudinal speed r r and / or transverse rotational speed r l The corresponding first speed r r and the second speed r l .

[0130] Next, based on the detection signals from the first rotation sensor SW3 and the second rotation sensor SW4 , the controller 4 permits the first and second Mecanum wheels 21R, 21L to drive, provided that the rotational speeds of the first and second Mecanum wheels 21R, 21L reach or exceed a predetermined value (a first threshold value).

[0131] Specifically, in step S4 following step S3 , the controller 4 determines whether any one of the following equations (13) and (14) is satisfied. This determination can confirm whether the bed 10 is actually transported (whether the bed 10 is actually moved).

[0132] r x ≥T1……(13) r y ≥T1……(14) In the above equations (13) and (14), T1 [1 / s] is the first threshold. The magnitude of the first threshold is stored in advance in the memory of the controller 4, etc., and the magnitude of the first threshold is set to be equal in the above equations (13) and (14). It should be noted that, as shown in the above description, Figure 9 In step S4, “r x / r y ” is not “r x Divide by r y The division value of "r x and r y Any of them".

[0133] In this case, the controller 4 determines that the bed body 10 is not actually conveyed, and does not allow the driving of the first motor 22R and the second motor 22L (Step S4: No). In this case, the control process proceeds to Step S5. In Step S5, the controller 4 sets the command rotational speed of each of the first motor 22R and the second motor 22L to zero.

[0134] In the case where the control process proceeds to Step S5, in Steps S7 to S9, the command rotational speed of each of the first motor 22R and the second motor 22L (more specifically, the assist speed described later) is maintained at zero (details of Steps S7 to S9 are described later). In this case, the controller 4 does not drive the first motor 22R and the second motor 22L, and ends the control process. Figure 9 The flowchart illustrated in FIG. 6.

[0135] On the other hand, in the case where at least one of the above expressions (13) and (14) is satisfied, the controller 4 determines that the bed body 10 is actually conveyed by the external force, and allows the driving of each of the first motor 22R and the second motor 22L (Step S4: Yes). In this case, the control process proceeds to Step S6. In Step S6, the controller 4 sets the command rotational speed of each of the first motor 22R and the second motor 22L (assist rotational speed) in order to assist the hand pushing of the bed body 10 based on the external force. The assist rotational speed corresponds to the command value of the above-described longitudinal rotational speed r x and the command value of the above-described lateral rotational speed r y .

[0136] Figure 10 Steps S11 to S15 of Figure 9 FIG. 6 respectively exemplify the processing performed in Step S6 of Figure 10 FIG. 6. That is, if the control process proceeds to Step S6, the controller 4 starts Step S11 of

[0137] In Step S11, the controller 4 determines the moving direction of the bed body 10 based on the longitudinal acceleration a x and the lateral acceleration a y estimated in Step S3 of Figure 9 . More specifically, the controller 4 involved in the present embodiment determines whether the moving direction of the bed body 10 is the forward-backward direction (the bed body 10 is advancing or retreating) or the left-right direction based on the longitudinal acceleration a x and the lateral acceleration a y .

[0138] More specifically, in Step S11, the controller 4 determines whether the following relational expression (15) is satisfied.

[0139] | a y | < T2 …… (15) In the above formula (15), T2 [m / s 2 ] is the second threshold value. The magnitude of the second threshold value is stored in advance in the memory of the controller 4 or the like, and the magnitude of the second threshold value is appropriately read out as needed.

[0140] If the above formula (15) is not satisfied, the controller 4 determines that the moving direction of the bed 10 is the left-right direction and advances the control flow to step S12 (step S11 : No). The details of the process when the control flow advances to step S12 will be described later.

[0141] On the other hand, when the above formula (15) is satisfied, the controller 4 determines that the moving direction of the bed 10 is the front-rear direction, and advances the control flow to step S13 (step S11 : Yes).

[0142] In step S13, the controller 4 determines whether the bed 10 is rotating around the bed 10 based on the detection signal of the six-axis sensor SW5. Figure 8 Specifically, in step S13 , the controller 4 determines whether the following relational expression (16) is satisfied.

[0143] |a ψ |≥T3……(16) In the above formula (16), a ψ [1 / s 2 ] is the angular acceleration of the yaw angle, T3[1 / s 2 ] is a third threshold value. The magnitude of the third threshold value is stored in advance in a memory or the like of the controller 4, and the magnitude of the third threshold value is appropriately read out as needed.

[0144] Here, when the above formula (16) is not satisfied, the controller 4 determines that the bed 10 is not rotating (not rotating), and advances the control process to step S14.

[0145] Entering step S14 corresponds to the case where it is determined that the bed 10 is in the process of moving forward and not rotating or in the process of moving backward and not rotating. In this case, the controller 4 performs the subsequent steps to determine the longitudinal acceleration a obtained by the first current sensor SW1 and the second current sensor SW2. x and lateral acceleration a y , both the compliance control as the first control and the speed increase control as the second control are executed.

[0146] On the other hand, when the above formula (16) is satisfied, the controller 4 determines that the bed 10 is rotating (is rotating), and advances the control process to step S15.

[0147] The case where the process proceeds to step S15 corresponds to a case where it is determined that the bed body 10 is turning while advancing or turning while retreating (i.e., a case where the bed body 10 is turning). In this case, the controller 4 performs control that is most suitable for turning, i.e., control that assists movement of the bed body 10 by hand in both the front-rear direction and the left-right direction.

[0148] The processes performed in steps S12 and S14 and the process performed in step S15 will be described below in order. In the cases where these steps are entered, the controller 4 drives the first and second Mecanum wheels 21R and 21L via the first and second electric motors 22R and 22L in a manner that assists movement of the bed body 10 in the direction of movement determined in step S11 described above. In this process, the controller 4 involved in the present embodiment performs compliant control as first control, or performs speed increase control as second control.

[0149] Compliant control refers to control performed by the controller 4 based on at least one of the acceleration (i.e., the longitudinal acceleration a x and the lateral acceleration a y ) estimated in step S3 described above. In this compliant control, the controller 4 sets an instruction value of the longitudinal velocity v x and an instruction value of the lateral velocity v y in a manner that follows movement of the bed body 10 by hand.

[0150] As described with respect to equations (9) to (12), by setting the instruction value of the longitudinal velocity v x and the instruction value of the lateral velocity v y , the instruction value of the first rotational speed r r and the instruction value of the second rotational speed r l are uniquely determined.

[0151] Hereinafter, the instruction value of the longitudinal velocity v x and the instruction value of the lateral velocity v y will be referred to as a longitudinal velocity instruction V x and a lateral velocity instruction V y , respectively. Also, the instruction value of the first rotational speed r r and the instruction value of the second rotational speed r l in each electric motor 22R, 22L will be referred to as a first instruction rotational speed R r and a second instruction rotational speed R l , respectively.

[0152] The longitudinal velocity instruction V x and the lateral velocity instruction V y are set by compliant control as in the present embodiment, which are equivalent to setting the first command speed R in a manner that follows the movement of the bed 10 r and the second command speed R l .

[0153] On the other hand, the speed increase control is a control executed by the controller 4 based on the acceleration estimated in step S3 and the command speed set in the compliance control. In the speed increase control, when the absolute value of the acceleration referred to in the compliance control is greater than a predetermined value (a fourth threshold value T4 described later), the controller 4 increases the longitudinal speed command V set in the compliance control to 0. x and lateral speed command V y (Especially the speed instructions V x 、V y The absolute value of

[0154] As in this embodiment, the longitudinal speed command V is set to x and lateral speed command V y increase, which is equivalent to making the first command speed R r and the second command speed R l (Especially the command speed R r 、R l The absolute value of

[0155] First, the case where the control process enters step S12 or step S14 is described. Figure 15 Steps S31 to S36 are respectively illustrated in Figure 10 That is, when the control flow enters step S12 or S14, the controller 4 Figure 15 The steps are executed sequentially starting from step S31.

[0156] For example, when entering from step S12 to Figure 15 In the case of the process of FIG, that is, when it is determined that “movement direction = left and right direction”, the controller 4 adjusts the horizontal acceleration a based on the horizontal acceleration a. y The compliant control is executed, and the speed increase control is executed based on the lateral speed command V obtained by the compliant control. y control.

[0157] On the other hand, when entering from step S14 to Figure 15 In the case of the process of FIG, that is, when it is determined that “moving direction = front-back direction”, the controller 4 adjusts the longitudinal acceleration a based on the longitudinal acceleration a. x Execute the compliance control and execute the longitudinal speed command V based on the compliance control. x The speed increases with control.

[0158] Next, the process from step S14 to Figure 15 The process of Figure 15 In the process, step S31 is related to the compliance control, and steps S32 to S34 are related to the speed increase control.

[0159] First, in step S31, the controller 4 Figure 11 The control module of the example inputs the longitudinal acceleration a x To calculate the longitudinal velocity v x The command value. As the input longitudinal acceleration a x It is estimated based on the detection signals of the first current sensor SW1 and the second current sensor SW2 and corresponds to the longitudinal acceleration a x The estimated value (measured value) of .

[0160] In this control module, s represents the Laplace operator, M represents the inertia of the bed 10 and the transport assist device 1 , and D represents the damping coefficient between the support point of the transporter 100 on the bed 10 (e.g., the headboard 11h) and the first and second Mecanum wheels 21R, 21L. K represents the spring constant between these support points and the first and second Mecanum wheels 21R, 21L. The values ​​of M, D, and K are preset and stored in the controller 4 .

[0161] However, assuming that the transport assist device 1, the bed 10, and the transporter 100 are considered as rigid bodies, the longitudinal velocity v generated when the first Mecanum wheel 21R and the second Mecanum wheel 21L rotate due to an external force is x The longitudinal acceleration a changes synchronously with the moving speed of the bed 10 and the conveyor 100 in the front-rear direction, and the magnitudes thereof are also consistent with each other. x By integrating the measured value over time, we can obtain the longitudinal speed instruction V such as following the movement of the bed 10 by hand. x .

[0162] However, in reality, the bed frame 12 of the bed 10 and the mounting member 7 of the transport assist device 1 are interposed between the support position of the bed 10 and the first and second Mecanum wheels 21R and 21L. x The moving speed of the bed 10 and the conveyor 100 may change with a delay due to the bending of the bed frame 12 or the like, or the actual longitudinal speed v x There will be a deviation in the value from this movement speed.

[0163] Modeling the effects of such delays and deviations is Figure 11The control module shown in the example. This control module means that the physical quantity corresponding to the force (longitudinal acceleration a x , lateral acceleration a y ) as input, and the speed command (longitudinal speed command V x , lateral speed command V y ) as a smooth control of the output.

[0164] exist Figure 11 First, the longitudinal acceleration a x The measured value of is input to the first module B1 after passing through the subtractor P2. In the first module, the longitudinal acceleration a is x The output of the first module B1 is shown with the longitudinal acceleration a x The size of the longitudinal velocity command V x The controller 4 sets the current longitudinal speed instruction V x The correction amount ΔV is added or accumulated to set the longitudinal speed command V x .

[0165] The output from the block B1 is multiplied by D / M in the second block B2 and then input to the subtractor P2 via the adder P1. x The multiplication value input to the subtractor P2 is subtracted from the measured value. This feedback is used to import the longitudinal speed command V x The attenuation is proportional to the load (especially the attenuation generated between the support position of the bed 10 and the first Mecanum wheel 21R and the second Mecanum wheel 21L).

[0166] The output from the block B1 is also input to the third block B3. In the third block B3, the correction value ΔV is further time-integrated. The output of the third block B3 is multiplied by K / M in the fourth block B4 and then input to the subtractor P2 via the adder P1. Similar to the multiplication value via the second block B2, the longitudinal acceleration a is obtained. x This feedback is used to introduce a restoring force proportional to the displacement (particularly, the restoring force generated by the deflection between the support position of the bed 10 and the first and second Mecanum wheels 21R, 21L).

[0167] By making the two feedbacks reflect the longitudinal acceleration a x The acceleration of the bed 10 (particularly, the acceleration at the support position of the transporter 100 ) can be estimated taking into account deflection, damping, etc. The velocity obtained by time-integrating this acceleration in the first module B1 is a velocity that can follow the movement of the bed 10 .

[0168] In addition, signal processing (for example, processing using a delay operator) for compensating for a time delay caused by feedback may be performed midway between the adder P1 and the subtractor P2 .

[0169] For example, Figure 12 As shown in the figure above, when the transport assist device 1, the bed 10, and the transporter 100 move at the same speed, the acceleration estimated by the first current sensor SW1 and the second current sensor SW2 is zero. In this case, the input to Figure 11 The longitudinal acceleration of the control module a x =0, the correction amount ΔV output from the control module is also 0. In this case, the transport support device 1 does not accelerate or decelerate.

[0170] On the other hand, Figure 12 As shown in the center figure, when the transporter 100 moves faster than the transport assisting device 1, the acceleration estimated by the first current sensor SW1 and the second current sensor SW2 is positive. In this case, an external force is applied to the bed 10 as if pushing it in (see arrow F1). In this case, the input to Figure 11 The longitudinal acceleration of the control module a x If the value of ΔV is positive, the correction value ΔV output from the control module is also positive. At this point, the restoring force associated with the fourth module B4 acts in a direction that increases the correction value ΔV (see arrow F3). As a result, the transport assistance device 1 accelerates with a delay relative to the application of the external force, so that the transport assistance device 1, the bed 10, and the transporter 100 have the same speed.

[0171] On the other hand, Figure 12 As shown in the figure below, when the transporter 100 moves slower than the transport assisting device 1, the acceleration estimated by the first current sensor SW1 and the second current sensor SW2 is negative. In this case, an external force is applied to the bed 10 as if pulling it back (see arrow F2). In this case, the input to Figure 11 The longitudinal acceleration of the control module a x If the value of the correction value ΔV is negative, the correction value ΔV output from the control module is also negative. At this point, the restoring force associated with the fourth module B4 acts in a direction that decreases the correction value ΔV (see arrow F4). As a result, the transport support device 1 is decelerated with a delay relative to the application of the external force, so that the transport support device 1, the bed 10, and the transporter 100 have the same speed.

[0172] In the following steps S32 to S34, the controller 4 executes the above-mentioned speed increase control. When the speed increase control is executed, the controller 4 increases the speed command value to a larger value as the rotation speed detected by the first rotation sensor SW3 and the second rotation sensor SW4 increases (refer to Figure 13 ). It should be noted that, Figure 13 The horizontal axis does not mean the value obtained by dividing the longitudinal speed by the lateral speed. Figure 13 The graph shown means that when the speed command value in the front-back direction (longitudinal direction) is set, the longitudinal speed v x The larger the value, the larger the speed command value is set. When setting the speed command value in the left and right directions (lateral direction), the lateral speed v y The larger the value, the larger the speed command value is set.

[0173] Specifically, in step S32, the controller 4 sets the longitudinal speed v x The larger the speed increase v off The larger the speed increase v is, the off . It can also be used instead of the longitudinal velocity v x , with longitudinal rotation speed r x The larger the speed increase v off The larger the speed increase v is, the off .

[0174] In addition, when entering from step S12 to Figure 15 In the case of a flow, instead of the longitudinal velocity v x The lateral velocity v y As the judgment object. As described above, the controller 4 uses the lateral speed v y The larger the speed increase v off The larger the speed increase v is, the off That is, the controller 4 is based on Figure 10 The moving direction determined in step S11 is increased by a speed of v off settings.

[0175] In the next step S33, the controller 4 determines whether the following relational expression (17) is satisfied. In step S33, the longitudinal acceleration a is determined. x Whether the absolute value of is greater than or equal to a predetermined value. By this determination, it is possible to detect whether the bed 10 is pushed in the moving direction (detect the pushing force).

[0176] |a x |≥T4……(17) In the above formula (17), T4 [m / s 2] is a fourth threshold value (a prescribed value). The magnitude of the fourth threshold value T4 as a prescribed value is stored in advance in a memory or the like of the controller 4, and the magnitude of the fourth threshold value T4 is read out as appropriate.

[0177] Note that, in the case where the flow proceeds from step S12 to Figure 15 , instead of the longitudinal acceleration a x , the lateral acceleration a y is taken as the comparison target. That is, the controller 4 makes a determination as to whether the acceleration in the direction of movement determined in step S11 is T4 or more. Figure 10

[0178] Here, in the case where the above expression (17) is satisfied (that is, in the case where the absolute value of the longitudinal acceleration a x is a prescribed value or more), the controller 4 determines that the bed 10 is being pushed, and causes the control flow to proceed to step S34 (step S33: YES).

[0179] In step S34, the controller 4 adds the speed increase amount v off to the speed command (longitudinal speed command V x ) calculated in step S31. The controller 4 takes the addition value thus obtained as the final speed command (auxiliary speed) (step S36). The auxiliary speed in the front-rear direction is the above-described longitudinal speed command V x . The auxiliary speed in the left-right direction is the above-described lateral speed command V y .

[0180] Note that, instead of the scheme of calculating the speed increase amount v off and adding the speed command to the speed increase amount v off , a scheme of calculating an increase ratio ( > 1) that increases as the rotational speed detected by the first rotation sensor SW3 and the second rotation sensor SW4 increases, and performing speed increase control by multiplying the speed command by the increase ratio can also be used.

[0181] On the other hand, in the case where the above expression (17) is not satisfied (that is, in the case where the absolute value of the longitudinal acceleration a x is less than a prescribed value), the controller 4 determines that the bed 10 is not being pushed, and causes the control flow to proceed to step S35 (step S33: NO).

[0182] In step S35, the controller 4 performs third control that decreases the speed command after the second control.

[0183] Specifically, in step S35, the controller 4 decreases the speed command V off ​the control process proceeds to step S34 on the basis of the value of the longitudinal velocity command V off The subtraction amount Δv2 can also be constant. In the case where the subtraction amount Δv2 is set to be constant, if the state where the bed 10 is not pushed is repeated, the speed increase amount v off is gradually reduced. In addition, it is configured so that the speed increase amount v off is not less than zero at the time of the subtraction. Thereby, the assist speed following the degree of movement of the bed 10 is ensured.

[0184] For example, in the case where the process proceeds from step S33 to step S34 in the n-th cycle, the longitudinal velocity command V x is increased by an amount corresponding to the speed increase amount v x of the longitudinal velocity v off . Thereafter, in the case where the process proceeds from step S33 to step S35 in the n+1-th cycle, the speed increase amount v off becomes a value obtained by subtracting the subtraction amount Δv2 from the value at the time of the n-th cycle. Thereafter, if the situation where the process proceeds from step S33 to step S35 is repeated, the longitudinal velocity command V x tends to decrease toward the value calculated in step S31.

[0185] Figure 14 is a graph comparing the assist rotational speed in the case where the compliant control is executed and the speed increase control is not executed (dotted line) and the assist rotational speed in the case where both the compliant control and the speed increase control are executed (solid line). Figure 14 The circles in FIG. 8 indicate the timing at which it is determined that the bed 10 is pushed (the timing at which the determination of step S33 is "Yes").

[0186] In the case where only the compliant control is executed, the assist rotational speed rises in delay to the movement of the bed 10 and thereafter, the assist rotational speed passes with the value following the movement.

[0187] On the other hand, in the case where both the compliant control and the speed increase control are executed, the assist rotational speed sharply rises every time it is determined that the bed 10 is pushed (see, for example, t = tl, t2, t3). On the other hand, if the period during which it is determined that the bed 10 is not pushed continues, the assist rotational speed after the rise gradually reduces with the passage of time (see, for example, tl < t < t2, t2 < t < t3).

[0188] More specifically, in FIG. 8, the period from the start of the rise of the assist rotational speed (assist speed) determined through the compliant control until the start of the descent thereof (the period from the rise of the dotted line until the descent thereof) corresponds to the period from the start of the rise of the assist rotational speed (assist speed) until the start of the descent thereof in FIG. 7. Figure 14 Figure 12 ​The so-called "bed push-in" shown in B. In this case, the determination of step S33 is appropriately "yes", and the speed is increased by the amount v each time. off A non-zero, positive value is set. For example, when the bed 10 is pushed relatively hard (when pushed with a strength that would result in a "YES" determination in step S33), the auxiliary rotation speed increases sharply as described above. On the other hand, when the bed 10 is pushed relatively softly (when pushed with a strength that would not result in a "YES" determination in step S33), the auxiliary rotation speed (auxiliary speed) gradually decreases toward a value sufficient to track the bed 10.

[0189] On the other hand, Figure 14 In the example, the period from when the assist speed (assist speed) determined by the compliance control starts to decrease (the period from when the dotted line turns to decrease until it reaches zero) is equivalent to the period Figure 12 In this case, the speed increase v is not “when the bed is pulled back” as shown in C. off The lower limit value (zero) is maintained. As a result, the assist rotation speed (assist speed) is maintained at the value determined by the compliance control and decreases toward zero.

[0190] Then, if the processing involved in step S36 is completed, the control process ends. Figure 10 and Figure 15 The process, enter Figure 9 Step S7.

[0191] It should be noted that Figure 15 In the description, when entering from step S12 to Figure 15 The same applies to the process. In this case, in the above description, the term "vertical" can be replaced with the term "horizontal," and the term "front and back" can be replaced with the term "left and right." The same applies to various mathematical formulas. In this case, the predetermined value such as the fourth threshold value T4 can be equal or different in the front-back direction and the left-right direction.

[0192] On the other hand, when the process proceeds from step S13 to step S15 , the controller 4 sets the assisting rotation speeds in both the longitudinal and lateral directions for assisting the bed 10 in turning.

[0193] Here, Figure 16 Steps S41 to S44 are respectively illustrated in Figure 10 That is, if the control flow enters step S15, the controller 4 starts Figure 16 The steps are executed sequentially starting from step S41.

[0194] First, in step S41, the controller 4 makes Figure 9The lateral acceleration a estimated in step S3 y The adjustment is performed in such a way that the longitudinal acceleration is reduced at a predetermined rate higher than 0. Specifically, the longitudinal acceleration a x The controller 4 maintains the value estimated in step S3. On the other hand, the lateral acceleration a y , the controller 4 converts it as shown in the following equation (18).

[0195] a y '=c y a y …… (18) In the above formula (18), c of the predetermined ratio is shown. y The ratio c is set in advance according to the size, weight, structure, etc. of the bed 10 and the transport assisting device 1 and stored in the controller 4. Specifically, the ratio c is set y is set to be less than 1 (0<c y <1), more specifically, the prescribed ratio c y is set to be less than 0.5 (0<c y <0.5).

[0196] The prescribed ratio c y The rotation center Ot of the bed 10 is set so as to be offset from the center position Pc of the first Mecanum wheel 21R and the second Mecanum wheel 21L toward the front end side of the bed 10 (see Figure 17 ).

[0197] It should be noted that if Figure 4 As shown, the center position Pc mentioned here can be the center position of the first Mecanum wheel 21R and the second Mecanum wheel 21L in the left-right direction, and the position intersecting the first rotation axis Oy1 and the second rotation axis Oy2 in the front-back direction.

[0198] In the next step S42, the controller 4 calculates the longitudinal acceleration a in the front-rear direction based on the longitudinal acceleration a estimated in step S3. x , performing compliant control as the first control.

[0199] In particular, regarding the front-rear direction, the controller 4 according to the present embodiment controls the longitudinal acceleration a based on the longitudinal acceleration a estimated in step S3. x , and the two are executed sequentially as the compliant control and the speed increase control as the second control. For details of the compliant control and the speed increase control in the front-rear direction, refer to Figure 15 By executing step S42 , the controller 4 sets the speed command in the front-rear direction as described above.

[0200] That is, with respect to the front-rear direction, after calculating a speed command (and furthermore, a commanded rotational speed of the first motor 22R and the second motor 22L) such as to follow the front-rear movement of the bed 10, control such as increasing the speed command (commanded rotational speed) is performed in synchronization with the fact that the bed 10 is pushed.

[0201] In the next step S43, the controller 4 adjusts the lateral acceleration a in the left-right direction (lateral direction) based on the lateral acceleration a adjusted in the above step S41. y ', execute the compliant control as the first control.

[0202] In particular, regarding the lateral direction, the controller 4 according to the present embodiment adjusts the lateral acceleration a based on the adjusted lateral acceleration a. y 'On the basis of executing the compliant control, the speed increase control as the second control is not executed. In this case, the controller 4 executes Figure 15 In the processes other than steps S32 to S35, speed instructions in the left and right directions are set.

[0203] That is, with respect to the left and right directions, although only the control is performed to calculate the speed instruction (and therefore, the command speed of the first motor 22R and the second motor 22L) such that the bed 10 slightly follows the lateral movement, the control is intentionally not performed to increase the speed instruction (command speed) in sync with the fact that the bed 10 is pushed.

[0204] In the next step S44 , the controller 4 sets the speed command set in step S42 as the assist speed in the front-rear direction, and sets the command rotation speed set in step S43 as the assist speed in the lateral direction.

[0205] if Figure 10 After the steps S12, S14 and S15 are completed, the control process enters Figure 9 In step S7, the controller 4 sets the longitudinal speed instruction V to the assist speed. x Or lateral speed command V y The first command speed R is converted into the following formula (19) and formula (20) determined in the same way as the above formula (5) and formula (6), respectively. r and the second command speed R l .

[0206] R r =60 (V x +V y ) / (2π·R)……(19) R l =60 (V x -Vy ) / (2π·R)……(20) In the above equations (19) and (20), "R" is the tire radius. In the present embodiment, when assisting in the front-rear direction, V x ≠0 and V y =0, when assisting in the left or right direction, V x =0 and V y ≠0, when assisting with turning V x ≠0 and V y ≠0.

[0207] For example, when it is determined that the moving direction of the bed 10 is the front-rear direction (when step S14 is executed), the controller 4 performs the following operation: Figure 7 As shown in the upper left and upper right figures, the first command speed R is set so that both the first Mecanum wheel 21R and the second Mecanum wheel 21L rotate forward or backward. r and the second command speed R l , and when making this setting, the absolute values ​​of the commanded rotation speeds of the first Mecanum wheel 21R and the second Mecanum wheel 21L are made equal (R r =R l ).

[0208] By setting the first command speed R r and the second command speed R l The absolute values ​​of are equal, and the movement in the front-rear direction can be stabilized regardless of the orientation of each caster 14.

[0209] In addition, when it is determined that the moving direction of the bed 10 is the left-right direction (when step S12 is executed), the controller 4 performs the following operation: Figure 7 As shown in the lower left figure of FIG, the first command speed R is set so that one of the first Mecanum wheel 21R and the second Mecanum wheel 21L rotates forward and the other rotates backward. r and the second command speed R l , and when making this setting, the absolute values ​​of the commanded rotation speeds of the first Mecanum wheel 21R and the second Mecanum wheel 21L are also made equal (R r =-R l ).

[0210] In addition, when it is determined that the bed 10 is turning (when step S12 is executed), the controller 4 performs the following operations: Figure 7 The first command speed R is set so that at least one of the first Mecanum wheel 21R and the second Mecanum wheel 21L rotates as shown in the lower right figure. r and the second command speed R lWhen making this setting, the rotation center Ot is located at Figure 17 In the illustrated position, the absolute values ​​of the rotational speeds of the first Mecanum wheel 21R and the second Mecanum wheel 21L are set to be different (|R r |≠|R l |).

[0211] Then, in step S8 following step S7, the controller 4 performs a safety control process. The details of this process are as follows: Figure 18 As shown in step S51 and step S52.

[0212] First, in step S51, the controller 4 determines whether Figure 9 The command speed R set by the process r 、R l The absolute value of is greater than or equal to a predetermined fifth threshold value T5. Here, the magnitude of the fifth threshold value T5 is stored in advance in a memory or the like of the controller 4, and the magnitude of the fifth threshold value T5 is read out as needed.

[0213] If the determination result in step S51 is "yes", the controller 4 proceeds the control process to step S52. In step S52, the controller 4 sets each command speed R r 、R l Change to the fifth threshold value T5.

[0214] On the other hand, if the determination in step S51 is "No", the controller 4 skips step S52 and returns. In this case, each command speed R r 、R l The size of is maintained smaller than the fifth threshold value T5.

[0215] Thus, the controller 4 according to the present embodiment is configured to: after the speed increase control as the second control, at the first command speed R r and the second command speed R l If the speed is less than a predetermined threshold value (fifth threshold value T5) (step S51: No), the first command speed R is maintained. r and the second command speed R l The value of the first command speed R r and the second command speed R l If the first command speed R is greater than the fifth threshold value T5 (step S51: Yes), the first command speed R r and the second command speed R l Change to the fifth threshold value T5.

[0216] Then, in the following Figure 9In step S9 of step S8, the controller 4 drives the first and second Mecanum wheels 21R and 21L via the first and second motors 22R and 22L in a manner that assists the movement of the bed 10 in the moving direction. At this time, the first and second motors 22R and 22L are driven in a manner that realizes the command rotational speed R r , R l determined by the above-described steps S5, S6, and S7.

[0217] Thus, when the bed 10 is moved by hand in the front-rear direction or the left-right direction, assistance in the moving direction is performed. On the other hand, when the bed 10 is moved in the front-rear direction while being turned, i.e., when the bed 10 is turned, the first and second Mecanum wheels 21R and 21L are driven via the first and second motors 22R and 22L in a manner that assists the movement of the bed 10 by hand in both the front-rear direction and the left-right direction.

[0218] Thus, instead of realizing a turn around the central position Pc as when assistance is performed only in the front-rear direction, a turn is realized in which the bed 10 is turned while being slid in the lateral direction. For example, when a right turn is performed as in Figure 17 , in addition to an external force that pushes the bed 10 forward, an external force that slides the bed 10 to the left (the opposite direction of the turning direction) also acts. Thus, assistance is performed by feeding back this external force, and a turn is realized in which the bed 10 is slid to the left (so-called drift).

[0219] Thus, as shown in Figure 17 , a turn is realized in which the turning center Ot is offset to the front end side of the bed 10, and the bed 10 can be turned in an orbit as shown in Figure 17 .

[0220] Suppose that, as shown in the prior example of Figure 19 , a turn is realized in which the central positions Pc of the first and second Mecanum wheels 21R and 21L are the turning center Ot. The turning radius of such an orbit is small, and interference can occur between the corners of the path and the bed 10, and thus it is not suitable.

[0221] In addition, when a left turn is performed, in addition to an external force that pushes the bed 10 forward, an external force that slides the bed 10 to the right (the opposite direction of the turning direction) also acts. Thus, assistance is performed by feeding back this external force, and a turn is realized in which the bed 10 is slid to the right, for which illustration is omitted. In this case, a smooth orbit as shown in Figure 17 can also be realized.

[0222] As described above, according to this embodiment, the controller 4 assists the hand in pushing the bed 10 to move in the front-back direction, and also assists the hand in pushing the bed 10 to move in the lateral direction (see FIG. Figure 16 (Steps S43 and S44). When the bed 10 turns, it is assumed that force is also applied in the radius of the turn, that is, in the lateral direction of the bed. Therefore, by assisting this lateral force, the bed 10 can be made to slide laterally during the turn. This increases the turning radius and reduces interference between the front or rear ends of the bed 10 and the corners of the passage. This effectively assists the bed 10 in turning.

[0223] In addition, if Figure 9 As illustrated in steps S2 and S3, by detecting the induced current, it is possible to estimate the torque that generates the induced current (the torque that rotates first Mecanum wheel 21R and second Mecanum wheel 21L), and furthermore, the acceleration corresponding to the torque. By estimating the acceleration of each Mecanum wheel 21R and 21L, it is possible to estimate the direction of the external force.

[0224] And, for the front and rear directions, the auxiliary such as following the movement of the bed 10 by hand is performed, and on the other hand, for the lateral direction, such as Figure 16 As illustrated in step S41, the acceleration in that direction is reduced, and compliance control based on that acceleration is performed. Reducing the lateral acceleration is equivalent to estimating the external force acting in the same direction to be smaller than the actual external force. By estimating the external force to be smaller, assistance is performed in the lateral direction that is insufficient to follow the movement of the bed with casters pushed by hand. As a result, excessive lateral slip (slip beyond the intention of the transporter 100) can be suppressed, so that the turning radius converges within an appropriate range. This facilitates appropriate assistance in turning the bed 10.

[0225] In addition, if you use Figure 17 As described above, by offsetting the center of rotation Ot of the bed 10 toward the front end, it is possible to achieve an action such as causing the rear end to swing more significantly than the front end when the bed 10 turns. By causing the rear end to swing more significantly, interference between the rear end and the corners of the passageway can be suppressed. This helps appropriately assist the bed 10 in turning.

[0226] In addition, if Figure 16 As shown in step S42 of the example, by performing speed increase control in the front-back direction, it is possible not only to follow the movement of the bed 10 pushed by hand, but also to reduce the load on the transporter 100 by the amount of increase in the command speed. As a result, the pushing feeling of the bed 10 in the front-back direction can be improved, thereby giving the transporter 100 a moderate "assistance feeling". On the other hand, in the lateral direction, asFigure 16 As exemplified in step S43, the speed increase control is intentionally not performed. Thereby, excessive sliding in the lateral direction (sliding beyond the intention of the conveyer 100) can be suppressed, so that the turning radius converges within an appropriate range. Thereby, the turning of the bed 10 is favorably assisted.

[0227] Further, by Figure 3-5 and Figure 7 exemplified as being configured and arranged, the first Mecanum wheel 21R and the second Mecanum wheel 21L can exert a pushing force like making the bed 10 perform a turning action when the first Mecanum wheel 21R and the second Mecanum wheel 21L are rotated in opposite directions. As thus configured, this is effective in appropriately assisting the turning of the bed 10 with casters.

[0228] Further, by making the absolute values of the command rotational speeds equal when moving forward and backward, more stable forward and backward movement can be achieved regardless of the orientation of the casters 14. On the other hand, by intentionally making the absolute values different when turning, turning along a desired track can be achieved.

[0229] <Other Embodiments> In the above embodiment, as the state sensor for determining whether the bed 10 advances or retreats, the first current sensor SW1 and the second current sensor SW2 are used, but the present disclosure is not limited to such a configuration. For example, the first rotation sensor SW3 and the second rotation sensor SW4 can be used as the state sensor, or a six-axis sensor SW5 can be used as the state sensor.

[0230] Further, in the above embodiment, the speed command (command value of the translational speed) is increased by the speed increase control, but such a configuration is not necessary.

[0231] For example, in steps S32 to S34, instead of the processing related to the speed command, processing like increasing the command rotational speed can be performed. In this case, processing like converting the speed command to the command rotational speed is provided between step S31 and step S32.

[0232] Symbol Explanation 1 conveyance assisting device 4 controller 10 bed (bed with casters) 14 caster 14F front wheel 14B rear wheel 21R first Mecanum wheel 211R first wheel body (wheel body) 212R first barrel-shaped roller (barrel-shaped roller) 21L second MR 211L second wheel body (wheel body) 212L second barrel roller (barrel roller) 22R first motor 22L second motor c y specified ratio F conveying surface Ot turning center Pc central position Oy1 first rotation axis (rotation axis) Oy2 second rotation axis (rotation axis) Or first tilt axis (tilt axis) Ol second tilt axis (tilt axis) SW1 first current sensor (state sensor) SW2 second current sensor (state sensor) SW5 six-axis sensor (turning sensor)

Claims

1. A conveying auxiliary device, which is used to assist in moving a bed with casters by hand, characterized in that: The conveying auxiliary device includes a first Mecanum wheel and a second Mecanum wheel, a first motor and a second motor, a state sensor, a rotation sensor, and a controller. The first Mecanum wheel and the second Mecanum wheel are mounted on the lower portion of the bed and contact the conveying surface of the bed. The first motor is drivingly connected to the first Mecanum wheel, and the second motor is drivingly connected to the second Mecanum wheel. The state sensor detects a signal corresponding to the rotational state of the first Mecanum wheel and the second Mecanum wheel. The rotation sensor detects the rotation of the bed around the rotation axis perpendicular to the conveying surface. The controller controls the first motor and the second motor, The controller determines whether the bed is moving forward or backward and whether the bed is rotating based on detection signals from the state sensor and the rotation sensor. When it is determined that the bed is moving forward and not rotating or moving backward and not rotating, the controller drives the first Mecanum wheel via the first motor and the second Mecanum wheel via the second motor in a manner that assists the hand-pushed bed with casters in moving forward and backward directions. When it is determined that the bed is rotating while moving forward or rotating while moving backward, the controller drives the first Mecanum wheel via the first motor and the second Mecanum wheel via the second motor in a manner that assists the movement of the bed with casters by hand in both the front-to-back direction and the lateral direction, where the lateral direction is orthogonal to the front-to-back direction and extends along the conveying surface.

2. The conveying assist device according to claim 1, wherein: The state sensor comprises a first current sensor and a second current sensor. The first current sensor detects an induced current flowing through the first motor when the first Mecanum wheel rotates, and the second current sensor detects an induced current flowing through the second motor when the second Mecanum wheel rotates. The controller estimates longitudinal acceleration indicating acceleration of the first and second Mecanum wheels in the front-rear direction and lateral acceleration indicating acceleration of the first and second Mecanum wheels in the lateral direction, based on detection signals from the first and second current sensors, respectively. The controller performs a first control based on at least one of the longitudinal acceleration and the lateral acceleration, wherein the command rotation speeds of the first motor and the second motor are set so as to follow the movement of the bed with casters pushed by hand. When it is determined that the bed is rotating while moving forward or rotating while moving backward, With respect to the front-rear direction, the controller performs the first control based on the longitudinal acceleration. On the other hand, In the lateral direction, the controller adjusts the lateral acceleration so that the lateral acceleration decreases at a prescribed rate higher than 0, and then performs the first control based on the adjusted lateral acceleration.

3. The conveying assist device according to claim 2, characterized in that The predetermined ratio is set so that the center of rotation of the bed is offset from a center position between the first Mecanum wheel and the second Mecanum wheel toward the front end of the bed.

4. The conveying assist device according to claim 2, wherein: When it is determined that the bed is moving forward and not rotating or moving backward and not rotating, the controller executes the first control based on the longitudinal acceleration and executes the second control to increase the command rotation speed. When it is determined that the bed is rotating while moving forward or rotating while moving backward, For the front-rear direction, the controller sequentially performs the first control and the second control based on the longitudinal acceleration. In the lateral direction, the controller performs the first control based on the adjusted lateral acceleration and does not perform the second control.

5. The conveying aid according to any one of claims 1 to 4, characterized in that The first Mecanum wheel and the second Mecanum wheel are arranged in the transverse direction. The first Mecanum wheel and the second Mecanum wheel each have a wheel body and a plurality of barrel-shaped rollers. The wheel body rotates around the rotation axis extending in the transverse direction, The plurality of barrel-shaped rollers are arranged along the outer circumference of the wheel body and rotate around inclined axes inclined relative to the front-rear direction and the lateral direction, respectively. The tilt axis of the first Mecanum wheel is tilted so that, with respect to the front-rear direction, the tilt axis of the first Mecanum wheel is symmetrical to the tilt axis of the second Mecanum wheel.

6. The conveying assisting device according to claim 5, characterized in that: When it is determined that the bed is in forward motion and not rotating, or in backward motion and not rotating, the controller sets the commanded rotational speeds of the first and second Mecanum wheels so that both the first and second Mecanum wheels rotate forward or backward, and when performing the setting, the absolute values ​​of the commanded rotational speeds of the first and second Mecanum wheels are equal. When it is determined that the bed is rotating while advancing or rotating while retreating, the controller sets the command rotation speed so that the absolute value of the command rotation speed differs between the first Mecanum wheel and the second Mecanum wheel.

Images