Transport aids and medical beds

Abstract

To appropriately start assisting a transverse movement by a mecanum wheel without needing to move a conveying person.SOLUTION: A conveyance assistance device 1 is configured to be attached to a medical bed 10 hand-pushed from the rear side, and includes: two mecanum wheels 21R and 21L arranged ahead of the rear wheels 14B; motors 22R and 22L for driving the mecanum wheels 21R and 21L respectively; an inertial sensor 5 for detecting a first turning operation in which the rear wheels 14B move in a predetermined direction At along a right-left direction with the two mecanum wheels 21R and 21L as support points; and a control device 4 connected to the inertial sensor 5 and the motors 22R and 22L electrically. When the first turning operation is detected, the control device 4 actuates the two mecanum wheels 21R and 21L through the motors 22R and 22L so as to execute a second turning operation to move front wheels 14F in the predetermined direction At with the rear wheels 14B as support points.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present disclosure relates to a transport assist device and a medical bed. [Background technology]

[0002] For example, Patent Document 1 discloses an auxiliary propulsion system that uses Mecanum wheels in its drive units. This auxiliary propulsion system includes a pair of left and right drive units that are connected to a chassis and configured with Mecanum wheels, and a sensor that monitors the acceleration of the drive units, and is configured to control the operation of the drive units based on data received from the sensor.

[0003] According to Patent Document 1, when the chassis moves laterally (sideways) in a predetermined direction, a force in the same direction is manually applied by the carrier. When the drive unit rotates as the chassis moves laterally due to this manual force, the rotation is detected and input to a control system. The control system starts the electric rotation of the drive unit based on the detected rotation. This electric rotation assists the lateral movement of the chassis. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2016-525977 Summary of the Invention [Problem to be solved by the invention]

[0005] When using the method disclosed in Patent Document 1, in order to start assisting with the Mecanum wheels, it is conceivable to apply a lateral force to an object such as a chassis and manually move the object laterally.

[0006] However, in the case of a heavy object such as a medical bed, simply applying force to the headboard or other part attached to the rear end of the object may not be enough to move the object smoothly sideways, which may cause problems with the assistance provided by the Mecanum wheels.In this case, to ensure that the assistance provided by the Mecanum wheels begins, the transporter must get around to the side of the object and push it sideways.

[0007] However, in a narrow environment such as an elevator, it may be difficult to get around the side of the object, making it difficult to push it sideways. This is inconvenient for assisting with Mecanum wheels.

[0008] The technology disclosed herein has been developed in consideration of these points, and its purpose is to appropriately start assisting lateral movement by Mecanum wheels without moving the transported person. [Means for solving the problem]

[0009] A first aspect of the present disclosure relates to a transportation assist device that is attached to an object having a plurality of casters with front and rear wheels and configured to be pushed from the rear side and assists in transporting the object. The transportation assist device includes a plurality of Mecanum wheels attached to the underside of the object and positioned forward of the rear wheels, a motor provided on each of the Mecanum wheels to operate each Mecanum wheel, a first sensor that detects a first turning motion in which the rear wheels move in a predetermined direction along the left-right direction around the Mecanum wheels, and a control device electrically connected to the first sensor and the motor, and when the first sensor detects the first turning motion, the control device operates at least one of the Mecanum wheels via the motor to perform a second turning motion in which the front wheels move in the predetermined direction around the rear wheels.

[0010] According to the first aspect, the first and second turning operations move the rear and front wheels in the same predetermined direction, respectively, but in opposite directions. Therefore, by performing the second turning operation after the first turning operation, the tilt of the object caused by each turning operation can be offset, and the posture of the object can be kept approximately constant. Here, during the second turning operation, the rear wheels after lateral movement by the first turning operation serve as a fulcrum, so the front wheels can be actively moved laterally without further lateral movement of the rear wheels.

[0011] Therefore, by successively performing the first turning operation and the second turning operation, it is possible to move both the front and rear wheels laterally in a predetermined direction while suppressing tilt of the object due to turning. By moving the front and rear wheels laterally, it is possible to move the entire object laterally in a predetermined direction.

[0012] Furthermore, when a force is applied to the rear end of the object in a predetermined direction, the multiple Mecanum wheels act as a brake for lateral movement. In this case, a rotation motion using the multiple Mecanum wheels as a fulcrum, i.e., a first rotation motion, is performed. In other words, this first rotation motion can be achieved without the transporter having to go around to the side of the object. Therefore, the second rotation motion triggered by the first rotation motion can also be initiated without moving the transporter. Because this second rotation motion is performed by operating the Mecanum wheels via a motor, the Mecanum wheels can begin assisting lateral movement without requiring excessive force from the transporter.

[0013] In this way, according to the first aspect, it is possible to appropriately start assisting the lateral movement of the object using the Mecanum wheels without moving the transporter. In addition, since the first rotation operation does not require a switch operation, the lateral movement of the object can be assisted through a more intuitive operation.

[0014] According to a second aspect of the present disclosure, the plurality of Mecanum wheels may be configured by two Mecanum wheels aligned in a left-right direction of the object, and the first sensor may be disposed between the two Mecanum wheels and configured to be capable of detecting an angular velocity around a yaw axis relative to the object.

[0015] According to the second aspect, by disposing the first sensor between the two Mecanum wheels, the centers of gravity of the two Mecanum wheels can be brought closer to the first sensor. This allows for accurate detection of the angular velocity around the center of rotation when the first turning motion is performed around the centers of gravity of the two Mecanum wheels. This allows for more appropriate timing for starting lateral movement assistance.

[0016] According to a third aspect of the present disclosure, the control device may calculate a turning angle of the rear wheels in the first turning operation based on the detection result of the first sensor and an operation time of the first turning operation, and when performing the second turning operation, the control device may operate at least one of the plurality of Mecanum wheels via the motor so that the magnitude of the turning angle of the rear wheels in the first turning operation matches the magnitude of the turning angle of the front wheels in the second turning operation.

[0017] According to the third aspect, the tilt of the object caused by the first turning operation and the second turning operation can be accurately offset, which is advantageous in keeping the posture of the object substantially constant, thereby enabling more appropriate assistance of lateral movement.

[0018] According to a fourth aspect of the present disclosure, the transport assist device may include a second sensor that detects the number of rotations of each of the plurality of Mecanum wheels, and when the first rotation motion is detected by the first sensor, the control device may perform the second rotation motion if the magnitude of the number of rotations is less than a first threshold, and when the magnitude of the number of rotations is equal to or greater than the first threshold, instead of performing the second rotation motion, actuate at least one of the plurality of Mecanum wheels via the motor to assist transport of the object in a diagonal direction.

[0019] According to the fourth aspect, it is possible to appropriately determine whether the transporter is requesting lateral movement or diagonal movement, and to more appropriately assist the object.

[0020] Furthermore, according to a fifth aspect of the present disclosure, the rear wheels may be two and arranged along the left-right direction of the object, and when performing the second turning operation, the control device may use one of the two rear wheels that is located at the tip end in the specified direction as a fulcrum.

[0021] The fifth aspect contributes to assisting lateral movement by combining the first turning motion and the second turning motion.

[0022] Furthermore, according to a sixth aspect of the present disclosure, the control device may be electrically connected to an operation switch that receives an operation input for instructing the object to move laterally, and when a lateral movement in a second predetermined direction is instructed via the operation switch, the control device may actuate at least one of the plurality of Mecanum wheels via the motor to perform a third rotation operation that exerts a propulsive force in the second predetermined direction.

[0023] According to the sixth aspect, in the third turning operation, a propulsive force is exerted to move the object laterally. Here, when the carrier supports the rear end of the object, exerting the propulsive force as described above realizes a motion that turns the front end of the object around the carrier as a fulcrum. By using the carrier positioned behind the object as a fulcrum, it is possible to assist the lateral movement of the object without causing a collision between the object and the wall, even when the object is placed along a wall.

[0024] Furthermore, according to a seventh aspect of the present disclosure, the control device may be configured to be able to individually switch between whether or not the second rotation operation is executable and whether or not the third rotation operation is executable.

[0025] According to the seventh aspect, the second rotation operation and the third rotation operation can be individually switched between enabled and disabled, which meets a wide range of needs and is also advantageous in preventing incorrect operation by the transporter.

[0026] An eighth aspect of the present disclosure relates to a medical bed equipped with the transport assist device according to the first aspect. [Effects of the Invention]

[0027] As described above, according to the present disclosure, it is possible to appropriately start assisting lateral movement by Mecanum wheels without moving the transported person. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a side view illustrating an example of the overall configuration of a transport assist device and a medical bed. FIG. [Figure 2] FIG. 2 is a bottom view illustrating an example of the overall configuration of the transport assist device and the medical bed. [Figure 3] FIG. 2 is a perspective view illustrating the configuration of a transport assist device. [Figure 4] FIG. 2 is a side view illustrating the configuration of a transport assist device. [Figure 5] FIG. 2 is a block diagram illustrating the configuration of a control system of the transport assist device. [Figure 6] FIG. 1 is a diagram for explaining the configuration of a Mecanum wheel. [Figure 7] 10A and 10B are diagrams for explaining the operation of a Mecanum wheel. [Figure 8] 4A and 4B are diagrams for explaining a first turning operation and a second turning operation. [Figure 9] FIG. 10 is a diagram for explaining a third turning operation. [Figure 10] 10 is a flowchart illustrating a process related to a second turning operation. [Figure 11] FIG. 10 is a diagram for explaining a moving distance in a first turning operation. [Figure 12] 10 is a flowchart illustrating a process related to a third turning operation. [Figure 13] FIG. 10 is a diagram for explaining a modified example of the second turning operation. DETAILED DESCRIPTION OF THE INVENTION

[0029] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0030] FIG. 1 is a side view illustrating the overall configuration of a transport assistance device 1 and a medical bed 10, and FIG. 2 is a bottom view illustrating the overall configuration of the transport assistance device 1 and a medical bed 10. As shown in FIG.

[0031] 3 is a perspective view illustrating the configuration of the transport auxiliary device 1, and FIG. 4 is a side view illustrating the configuration of the transport auxiliary device 1. Furthermore, FIG. 5 is a block diagram illustrating the configuration of a control system of the transport auxiliary device 1.

[0032] As shown in Figures 1 and 2, a transport assistance device 1 according to this embodiment is attached to a medical bed (hereinafter simply referred to as "bed") 10 as an object. The bed 10 is equipped with a plurality of casters 14, each having a front wheel 14F and a rear wheel 14B, and is configured to be pushed manually from the rear side. As will be described later, the transport assistance device 1 can assist in the transport of the bed 10 by pushing it manually.

[0033] Hereinafter, one longitudinal side of the bed 10 (head side) will be referred to as the "rear" and the other longitudinal side (foot side) will be referred to as the "front." Similarly, one lateral side of the bed 10 will be referred to as the "right" and the other lateral side will be referred to as the "left." The longitudinal direction may also be referred to as the "front-to-back direction" along the Y axis, and the lateral direction may also be referred to as the "lateral direction" or "left-to-right direction" along the X axis.

[0034] As shown in Fig. 1, the bed 10 includes a bed body 11 on which a mattress (not shown) is placed, a frame 12 that supports the bed body 11 from below, a lifting device 13 that raises and lowers the bed body 11 relative to the frame 12, and a plurality of casters 14 (four in the illustrated example) arranged on the underside of the bed 10. The bed 10 according to this embodiment is a so-called "medical bed with casters." This bed 10 can weigh, for example, 60 kg or more and 300 kg or less.

[0035] Here, the bed body 11 has a headboard 11h arranged at the rear side of the bed 10, a footboard 11f arranged at the front side of the bed 10, and side rails 11s arranged on both the left and right sides of the bed 10.

[0036] Of these, the headboard 11h functions as a push part to which a carrier applies force from behind in order to manually move the bed 10. A handle, a grip, or other member may be attached to the headboard 11h, and these members may be used as the push part.

[0037] The frame 12 is also configured in a rectangular frame shape as shown in Figure 2, and has a front frame 12F that extends in the left-right direction and is positioned in front of the bed 10, a right frame 12R that extends in the front-to-rear direction and is positioned on the right side of the bed 10, a left frame 12L that extends in the front-to-rear direction and is positioned on the left side of the bed 10, and a rear frame 12B that extends in the left-to-right direction and is positioned behind the bed 10.

[0038] 1 and 2, the front wheels 14F and rear wheels 14R that make up the plurality of casters 14 are arranged at the four corners of the underside of the bed 10, with two of each being provided along the left and right direction. The plurality of casters 14 support the frame 12, the lifting device 13, and the bed body 11 relative to the floor surface. Each caster 14 is a so-called free caster, and has a mounting part 14a fixed to the underside of the bed 10, a fork part 14b that can rotate around a rotation axis Oc relative to the mounting part 14a, and a wheel 14c that is rotatably supported by the fork part 14b.

[0039] The transport auxiliary device 1 is disposed so as to bridge the center in the front-rear direction of the right frame 12R and the center in the front-rear direction of the left frame 12L in the frame 12 supported by the aforementioned casters 14. The transport auxiliary device 1 is disposed in the center in the left-right direction, and is disposed between the front wheel 14F and the rear wheel 14B in the front-rear direction.

[0040] As shown in FIG. 2, the transportation assistance device 1 includes a plurality of motorized Mecanum wheels 2, a battery 3, a control device 4, and an inertial sensor 5 as a first sensor for detecting a first turning motion described below.

[0041] 5, the multiple (two in the illustrated example) motorized Mecanum wheels 2 have multiple Mecanum wheels 21R, 21L and motors 22R, 22L. The multiple Mecanum wheels 21R, 21L are attached to the underside of the bed 10 and are disposed in front of the rear wheels 14B. The motors 22R, 22L are provided on each of the multiple Mecanum wheels 21R, 21L and operate each Mecanum wheel 21R, 21L.

[0042] In particular, the multiple Mecanum wheels 21R, 21L according to this embodiment are configured by two Mecanum wheels 21R, 21L lined up along the left-right direction of the bed 10, as shown in Fig. 2 etc. The two Mecanum wheels 21R, 21L may be arranged so as to line up along the front-rear direction of the bed 10, or may be arranged so as to line up along an oblique direction inclined both in the front-rear direction and the left-right direction. Details of the Mecanum wheels 21R, 21L and the motors 22R, 22L will be described later.

[0043] Meanwhile, the battery 3, the control device 4, and the inertial sensor 5 are housed in a housing box 6, as shown in Fig. 2. The battery 3 is a lithium battery. This battery 3 is equipped with a voltage monitoring function.

[0044] The inertial sensor 5 is configured to be able to detect at least the angular velocity around the yaw axis (that is, the Z axis along the up-down direction of the bed 10) Oz with the bed 10 as the reference.

[0045] Specifically, the inertial sensor 5 according to this embodiment can detect not only the angular velocity around the yaw axis Oz, but also the acceleration in three directions, namely, the front-to-back, left-to-right, and up-to-down directions of the bed 10, the angular velocity around the roll axis (the Y axis along the front-to-back direction) and the angular velocity difference around the pitch axis (the X axis along the left-to-right direction) relative to the bed 10. The detection signal of the inertial sensor 5 is input to the control device 4. As will be described later, the inertial sensor 5 can detect a rotational movement with a plurality of Mecanum wheels 21R, 21L as fulcrums.

[0046] The control device 4 is configured with a control board having a CPU, memory, input / output bus, etc., and is capable of performing various calculations based on the detection signal of the inertial sensor 5. The control device 4 is electrically connected to the inertial sensor 5 and the motors 22R and 22L.

[0047] For example, the control device 4 can determine the direction and magnitude of the force applied by the carrier based on the acceleration in the three directions. The control device 4 can also determine the direction and speed of movement of the bed 10 by integrating the acceleration in the three directions with respect to time.

[0048] In addition, the control device 4 can determine the posture of the bed 10 based on the angular velocity around the three axes, determine the start and end of the first and second rotation operations described below, and determine whether or not the bed is traveling on a slope.

[0049] Furthermore, the control device 4 can determine the control parameters of the motors 22R, 22L by referring to the detection signal of the encoder 22b (described later) in addition to the detection signal of the inertial sensor 5. The control device 4 can individually control each of the motors 22R, 22L, and therefore the corresponding Mecanum wheels 21R, 21L, by inputting signals corresponding to the control parameters thus determined to the motors 22R, 22L.

[0050] In addition, the control device 4 is also electrically connected to the operation switch 8 shown in Fig. 1. This operation switch 8 is a so-called remote controller, and is configured to receive an operation input for instructing lateral movement of the bed 10. The control device 4 and the operation switch 8 may be configured to send and receive signals via wireless communication or via wired communication. Although detailed illustration is omitted, the operation switch 8 according to this embodiment is configured to be detachable from each of the headboard 11h, the side rail 11s, and the footboard 11f.

[0051] Each motorized Mecanum wheel 2 and the storage box 6 are both attached to a fixture 7, and are attached to the underside of the bed 10 via this fixture 7. The fixture 7 is detachable from the underside of the bed 10. In other words, the transport assistance device 1 according to this embodiment can be retrofitted to the bed 10 and can be detached as needed.

[0052] More specifically, as shown in FIG. 3, the mounting fixture 7 according to this embodiment has a front rail member 71f and a rear rail member 71b that are detachable from the right frame 12R and the left frame 12L, a first bracket 72 that rotatably supports each motorized Mecanum wheel 2, and a tension spring 75 that biases each motorized Mecanum wheel 2 via the first bracket 72.

[0053] The front rail member 71f and the rear rail member 71b are spaced apart in the front-to-rear direction and each spans the center of the right frame 12R and the center of the left frame 12L in the front-to-rear direction. The storage box 6 and the two motorized Mecanum wheels 2 are disposed in the space between the front rail member 71f and the rear rail member 71b.

[0054] Here, the storage box 6 is fixed to the front rail member 71f and the rear rail member 71b via dedicated brackets. As shown in FIG. 2, the storage box 6 is located in the center in the left-right direction, with one motorized Mecanum wheel 2 provided on each of its left and right sides. That is, the storage box 6, as well as the control device 4, battery 3, and inertial sensor 5 housed in the storage box 6, are arranged between the two motorized Mecanum wheels 2 in the left-right direction, more specifically, between the two Mecanum wheels 21R, 21L. Note that it is not essential to arrange the inertial sensor 5 between the two Mecanum wheels 21R, 21L.

[0055] Hereinafter, of the two motorized Mecanum wheels 2, the one located on the right side may be referred to as the "first motorized Mecanum wheel 2R," and the other located on the left side may be referred to as the "second motorized Mecanum wheel 2L."

[0056] As shown in Figure 3, the first bracket 72 located on the right side is connected to the rear rail member 71b via a first rotating shaft 73 located at its rear end. This first bracket 72 is supported on the rear rail member 71b so as to be swingable around the first rotating shaft 73. In addition, the front end of the first bracket 72 is connected to the first motorized Mecanum wheel 2R via a second rotating shaft 74. The first motorized Mecanum wheel 2R is supported on the first bracket 72 so as to be rotatable around the second rotating shaft 74.

[0057] One end of a tension spring 75 is anchored to the upper end of the first bracket 72. The other end of the tension spring 75 is anchored to a second bracket 76 fixed to the front rail member 71f (see also FIG. 4).

[0058] The first bracket 72 can be considered a bell crank that rotates around the first rotation shaft 73, with the tension spring 75 as the driving body and the first motorized Mecanum wheel 2R as the driven body. In other words, when one end of the tension spring 75 pulls the upper end of the first bracket 72, the first bracket 72 rotates around the first rotation shaft 73, pressing the first motorized Mecanum wheel 2R against the floor surface. The first bracket 72 and tension spring 75 function as a suspension for the first bracket 72. This makes it easy to overcome steps.

[0059] The above describes the components of the mounting fixture 7 that are related to the first motorized Mecanum wheel 2R, but the same applies to the components of the second motorized Mecanum wheel 2L. In the above description, the "first motorized Mecanum wheel 2R" can be read as the "second motorized Mecanum wheel 2L" as appropriate.

[0060] Additionally, the front rail member 71f, the rear rail member 71b, the left and right first brackets 72, and the left and right second brackets 76 are all made of an aluminum alloy. By using an aluminum frame for the front rail member 71f, the rear rail member 71b, etc., weight can be reduced and attachment to the bed 10 can be facilitated.

[0061] Next, the details of each motorized Mecanum wheel 2 will be described.

[0062] Fig. 6 is a diagram for explaining the configuration of the Mecanum wheels 21R, 21L, and Fig. 7 is a diagram for explaining the operation of the Mecanum wheels 21R, 21L. Fig. 7 corresponds to a plan view of the bed 10 as seen from above.

[0063] First, of the two motorized Mecanum wheels 2, the first motorized Mecanum wheel 2R located on the right side is equipped with a first Mecanum wheel 21R and a first motor 22R that drives this Mecanum wheel 21R (the first motor 22R is only shown in Figure 5).

[0064] Similarly, of the two motorized Mecanum wheels 2, the second motorized Mecanum wheel 2L located on the left side is equipped with a second Mecanum wheel 21L and a second motor 22L that drives this Mecanum wheel 21L (the second motor 22L is only shown in Figure 5).

[0065] As shown in FIG. 6, each of the first and second Mecanum wheels 21R, 21L is formed by attaching a plurality of barrel-shaped rollers inclined at 45° to the center of the wheel body on the circumference of the wheel body.

[0066] In addition, as shown in Figures 6 and 7, the first and second Mecanum wheels 21R and 21L are arranged so that the barrel-shaped rollers are mirror-symmetrical to each other with respect to a mirror plane extending along the front-to-rear direction (the barrel-shaped rollers are arranged so that their inclination directions are opposite to each other).

[0067] Furthermore, when viewed from above as shown in Fig. 7, the inclination direction of each barrel-shaped roller extends from the rear to the front along the front-rear direction, and from the inside to the outside in the left-right direction (from the center in the left-right direction to the right or left). Note that the inclination direction of each barrel-shaped roller is not limited to the example shown in Fig. 7 etc.

[0068] The first and second Mecanum wheels 21R, 21L are connected to each other via the front rail member 71f and rear rail member 71b shown in Figure 3 etc. Therefore, the first and second Mecanum wheels 21R, 21L move together in the front-to-rear and left-to-right directions, and rotate together with the first and second Mecanum wheels 21R, 21L as fulcrums.

[0069] In this case, since the inertial sensor 5 is disposed between the two Mecanum wheels 21R, 21L, this inertial sensor 5 detects the angular velocity of the rotational movement with the first and second Mecanum wheels 21R, 21L as the fulcrum (more specifically, the rotational movement around the yaw axis Oz that passes through the center position of the first and second Mecanum wheels 21R, 21L). The center position here refers to the center of gravity of the first and second Mecanum wheels 21R, 21L in a plan view.

[0070] On the other hand, the motors 22R, 22L for operating the Mecanum wheels 21R, 21L are each configured as a DC brushless motor with an encoder. The first and second motors 22R, 22L are both electrically connected to the control device 4 and are operated by receiving signals from the control device 4.

[0071] Here, 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 and second motors 22R, 22L into the corresponding Mecanum wheels 21R, 21L, respectively, the entire device can be simplified and made compact.

[0072] Specifically, the first and second motors 22R, 22L each have a motor body 22a with a stator and rotor (not shown) that generate rotational power, and an encoder 22b that detects the rotation speed and rotation angle of the motor body 22a. For example, when the Mecanum wheels 21R, 21L rotate due to force applied by a carrier, the encoder 22b detects the rotation speed and rotation angle of the corresponding Mecanum wheels 21R, 21L. Each encoder 22b functions as a second sensor that detects the rotation speed of each of the two Mecanum wheels 21R, 21L. The detection signal from the encoder 22b is input to the control device 4 as appropriate.

[0073] The rotation of the first motor 22R rotates the first Mecanum wheel 21R, and the rotation of the second motor 22L rotates the second Mecanum wheel 21L. By changing the rotation direction of each motor 22R, the corresponding Mecanum wheel 21R, 21L can be switched between forward and backward rotation.

[0074] By operating the first and second motors 22R, 22L based on detection signals from the inertial sensor 5, etc., the Mecanum wheels 21R, 21L can be rotated forward or backward individually. This allows the first and second Mecanum wheels 21R, 21L to exert a propulsive force, which can assist in transporting the bed 10.

[0075] For example, as shown in the upper left of Figure 7, rotating both the first and second Mecanum wheels 21R, 21L forward can assist in moving the bed 10 forward. Similarly, rotating both the first and second Mecanum wheels 21R, 21L backward can assist in moving the bed 10 backward (not shown).

[0076] 7, rotating one of the first and second Mecanum wheels 21R, 21L forward and rotating the other backward can assist lateral movement (movement along the left-right direction) of the bed 10. For example, rotating the first Mecanum wheel 21R backward and rotating the second Mecanum wheel 21L forward can assist lateral movement of the bed 10 to the right. In this case, it is preferable to make the amount of rotation of one wheel that is rotated forward equal to the amount of rotation of the other wheel that is rotated backward.

[0077] Furthermore, as shown in the lower left of Figure 7, driving only one of the first and second Mecanum wheels 21R, 21L to rotate forward or backward can assist the diagonal movement of the bed 10. For example, rotating only the second Mecanum wheel 21L forward can assist the bed 10 moving forward in a diagonal direction to the right. On the other hand, rotating only the first Mecanum wheel 21R forward can assist the bed 10 moving forward in a diagonal direction to the left (not shown).

[0078] Furthermore, as shown in the lower right of Figure 7, the same operation as that for assisting diagonal movement can be used to assist turning around one of the two rear wheels 14B. For example, by rotating only the second Mecanum wheel 21L forward, it is possible to assist turning in a clockwise direction around the right rear wheel 14B. On the other hand, by rotating only the second Mecanum wheel 21L backward, it is possible to assist turning in a clockwise direction around the left front wheel 14F.

[0079] Assistance for diagonal movement or turning of the bed 10 can also be achieved by varying the rotation amount (= number of rotations × operating time) of one of the first and second Mecanum wheels 21R, 21L from the rotation amount of the other. For example, by rotating the first Mecanum wheel 21R forward and the second Mecanum wheel 21L backward, and by making the rotation amount of the first Mecanum wheel 21R smaller than that of the second Mecanum wheel 21L, forward movement of the bed 10 in a diagonal direction to the right can be assisted. The angle of inclination in the diagonal direction (the angle of inclination relative to the front-to-back or left-to-right direction) can be adjusted by varying the difference in the rotation amount of the two Mecanum wheels 21R, 21L. On the other hand, when assisting turning of the bed 10, the position of the center of rotation can be adjusted by varying the difference in the rotation amount of the two Mecanum wheels 21R, 21L.

[0080] The assistance by the first and second Mecanum wheels 21R, 21L is performed so as to exert a propulsive force in the same direction as the force applied by the carrier to the bed 10 (specifically, the headboard 11h).

[0081] For example, in this embodiment, when the carrier applies force to the bed 10, causing each of the Mecanum wheels 21R, 21L to rotate, the number and direction of rotation are detected by the encoder 22b, and the control device 4 generates a control signal based on the detection result and inputs it to the motors 22R, 22L to perform assistance. Alternatively, when the carrier applies force to the bed 10, the inertial sensor 5 detects the acceleration corresponding to the force, and the control device 4 generates a control signal based on the detection result and inputs it to the motors 22R, 22L to perform assistance. When acceleration is used, unnecessary data may be cut using a digital filter to suppress variations due to vibration.

[0082] In this embodiment, an upper limit is set for the motor torque (current value) of the first and second motors 22R, 22L, which makes it possible to prevent the bed 10 from moving independently due to excessive propulsive force.

[0083] Furthermore, the first and second Mecanum wheels 21R, 21L are allowed to rotate forward and backward even when the corresponding motors 22R, 22L are not driven, which reduces wobbling when the bed 10 is pushed and moves, making it possible to stabilize the transportation of the bed 10.

[0084] The lateral movement of the bed 10 using the transport assist device 1 will be described below with reference to Fig. 8 and Fig. 9. Here, Fig. 8 is a diagram for explaining the first and second turning operations, and Fig. 9 is a diagram for explaining the third turning operation.

[0085] According to the above-mentioned method, in order to start the assistance of the lateral movement as illustrated in the upper right of FIG. 7, it is conceivable to apply a lateral force to the bed 10 and manually move the bed 10 laterally.

[0086] In contrast, the transport assistance device 1 of this embodiment can assist the lateral movement of the bed 10 by using a turning operation as illustrated in the lower right of Figure 7 instead of the lateral movement as illustrated in the upper right of the same figure.

[0087] Specifically, as shown in Figure 8(a), a case will be exemplified in which the bed 10 is moved laterally so as to move closer to the wall W located to the left as seen from the person 100. In such a case, it is common to apply force to the bed 10 from the side of the bed 10, but we will consider a case in which a lateral force is applied to the rear end of the bed 10 (for example, the headboard 11h shown in Figure 1) without moving the person 100.

[0088] In this case, the first and second Mecanum wheels 21R, 21L act as brakes, preventing lateral movement. As a result, the bed 10 rotates around the first and second Mecanum wheels 21R, 21L as fulcrums. This achieves a first rotational motion in which the rear wheels 14B move in a predetermined direction At along the left-right direction, with the center of gravity of the first and second Mecanum wheels 21R, 21L as the rotation center P1 (see arrow A1 in FIG. 8(a)). The predetermined direction At is one direction along the left-right direction. In the example of FIG. 8, the predetermined direction At coincides with the left direction (downward on the paper).

[0089] As described above, this first turning motion is fulcrum-based on the first and second Mecanum wheels 21R, 21L, and therefore can be detected by the inertial sensor 5. At this time, the control device 4 can determine whether the left or right rear wheel 14B has moved closer to the wall W, based on the positive or negative angular velocity detected by the inertial sensor 5.

[0090] Then, as shown in FIG. 8(b), when the inertial sensor 5 detects a first turning operation, the control device 4 according to this embodiment operates at least one of the two Mecanum wheels 21R, 21L via the motors 22R, 22L to perform a second turning operation in which the rear wheel 14B serves as a fulcrum (center of rotation P2) and the front wheel 14F moves in the same predetermined direction At as the first turning operation (see arrow A2 in FIG. 8(b)).

[0091] More specifically, when performing the second turning operation, the control device 4 sets the one of the two rear wheels 14B that is located on the leading edge side in the predetermined direction At as the rotation center P2. In the example of FIG. 8, the leading edge side in the predetermined direction At coincides with the left side in the left-right direction. Therefore, in this example, the left rear wheel 14B becomes the rotation center P2. Note that if the predetermined direction At were to be the right direction, the leading edge side in the predetermined direction At would coincide with the right side in the left-right direction.

[0092] Here, turning around the left rear wheel 14B as the center of rotation P2 can be achieved by rotating the Mecanum wheel 21R, which is located on the opposite side of the rear wheel 14B in the left-right direction (the right side in the example of FIG. 8), forward by a predetermined amount (see arrow Ar in FIG. 8(b)). At that time, in order to adjust the position of the center of rotation P2, the other Mecanum wheel 21L may be rotated forward or backward by a relatively small amount (see arrow Al in FIG. 8(b)).

[0093] In this case, because the transport assist device 1 is disposed in front of the rear wheels 14B, the direction of the second pivoting operation is opposite to the direction of the first pivoting operation. For example, in the example shown in FIGS. 8(a) and 8(b), the first pivoting operation is a clockwise rotation, and the second pivoting operation is a counterclockwise rotation. By successively performing pivoting operations in opposite directions, the bed 10 can be slid laterally as shown in FIG. 8(c). Furthermore, by using the left rear wheel 14B as the rotation center P2 during the second pivoting operation, the bed 10 can be slid laterally without moving away from the wall W.

[0094] Incidentally, a lateral force is also applied to the rear end of the bed 10 when it is moved forward or backward in a diagonal direction. In this case, the first rotation motion with the first and second Mecanum wheels 21R, 21L as the fulcrum is detected regardless of whether the second rotation motion is required. It would be inconvenient if the second rotation motion were unintentionally performed when trying to manually move the bed 10 in a diagonal direction.

[0095] Here, the first pivoting motion for moving the bed 10 laterally is a rotational motion on the spot, so the first and second Mecanum wheels 21R, 21L do not rotate as much as the first pivoting motion for moving forward or backward diagonally.

[0096] Therefore, when the inertial sensor 5 detects the first turning operation, the control device 4 acquires the number of rotations of each Mecanum wheel 21R, 21L via the encoder 22b, and executes the second turning operation when the magnitude of the acquired number of rotations or the difference between the number of rotations between the left and right wheels is less than a predetermined first threshold Δv1. On the other hand, when the magnitude of the number of rotations or the difference between the number of rotations between the left and right wheels is equal to or greater than the first threshold Δv1, instead of executing the second turning operation, the control device 4 activates at least one of the two Mecanum wheels 21R, 21L via the motors 22R, 22L to assist in transporting the bed 10 in a diagonal direction.

[0097] Note that instead of or in addition to encoder 22b, case distinction may be made using the detection signal of inertial sensor 5. This makes it possible to distinguish between a turn on the spot and a lateral movement and suppress the execution of the second turning operation when the turn is made. In this case, when the first turning operation is detected by inertial sensor 5, control device 4 first acquires the angular velocity of the first turning operation through inertial sensor 5. Thereafter, control device 4 executes the second turning operation when the amount of change in the acquired angular velocity is less than a predetermined second threshold, but does not execute the second turning operation when the amount of change in the angular velocity is equal to or greater than the threshold.

[0098] 10 and 11, the rotation amount (= number of rotations × operation time) of each of the first and second motors 22R, 22L can be determined based on the rotation angle θ of the rear wheels 14B relative to the rotation center P1 in the first rotation operation, the operation time t of the first rotation operation, and various dimensions of the bed 10, such as the distance from the rotation center P1 to the headboard 11h. Alternatively, the rotation amount (= number of rotations × operation time) of each of the first and second motors 22R, 22L may be constant.

[0099] Next, assistance when moving the bed 10 away from the wall W or the like will be described.

[0100] For example, when the bed 10 is close to a wall W as shown in FIG. 9(a) (when the bed 10 is placed along the wall), it is conceivable to apply a lateral force to the rear end of the bed 10, moving it away from the wall W. However, when such a force is applied, a rotation motion occurs with the first and second Mecanum wheels 21R, 21L as fulcrums, similar to the first rotation motion described above, and the front end of the bed 10 (the part on the footboard 11f side) may move toward the wall W. In order to prevent a collision between the bed 10 and the wall W, it is advantageous to avoid such movement as much as possible.

[0101] 9(a) and 9(b), when a lateral movement in the second predetermined direction Au is instructed via the operation switch 8, the control device 4 according to this embodiment activates at least one of the two Mecanum wheels 21R, 21L via the motors 22R, 22L to perform a third rotation operation that exerts a propulsive force in the second predetermined direction Au (see arrow A3 in FIG. 9(b)). Here, the second predetermined direction Au is one direction in the left-right direction relative to the bed 10. In the example of FIG. 9, the second predetermined direction Au coincides with the diagonally upward direction on the paper.

[0102] The propulsive force in the second predetermined direction Au can be realized by rotating one of the two Mecanum wheels 21R, 21L forward by a predetermined amount and rotating the other backward by the same amount, as shown in the upper right corner of Fig. 7 (see arrows Ar' and Al' in Fig. 9(b)). By operating each of the Mecanum wheels 21R, 21L in this way, a rotation is realized around the center of rotation P3, which is the person 100 supporting the headboard 11h, as shown by arrow A3 in Fig. 9(b).

[0103] The Mecanum wheels 21R, 21L are driven only while an operation input is being made to the operation switch 8. Therefore, the turning angle in the third turning operation can be adjusted according to the operation time of the operation switch 8.

[0104] Then, by manually pushing the bed 10 from the rear after the third turning operation has been performed, the entire bed 10 can be moved away from the wall W as shown by arrow A4 in FIG. 9(c).

[0105] The third pivoting motion can also be used to change the direction of the bed 10 on the spot. Furthermore, when the third pivoting motion is performed, a force in the second predetermined direction Au is applied to the rear end of the bed 10, thereby enabling the bed 10 to slide while maintaining a posture parallel to the wall W.

[0106] The control device 4 is also configured to be able to individually switch between whether or not a second rotation operation triggered by the first rotation operation is executable and whether or not a third rotation operation triggered by an operation input to the operation switch 8 is executable. That is, the control device 4 can individually switch between on and off the second rotation operation and the third rotation operation, thereby enabling only one of the operations, or enabling or disabling both of the operations.

[0107] Next, specific examples of processing related to the first turning motion, the second turning motion, and the third turning motion will be described. Here, Fig. 10 is a flowchart illustrating processing related to the second turning motion, Fig. 11 is a diagram for explaining the movement amount in the first turning motion, and Fig. 12 is a flowchart illustrating processing related to the third turning motion.

[0108] First, in the processing related to the second turning operation, the control process proceeds to step S11 in Fig. 10. In this step S11, the control device 4 reads detection signals from the inertial sensor 5, the encoder 22b, and the like.

[0109] In the following step S12, the control device 4 determines whether or not a first turning motion has been detected based on the angular velocity about the yaw axis Oz detected by the inertial sensor 5. If this determination is NO, the control process returns. On the other hand, if the determination in step S12 is YES, the control process proceeds to step S13.

[0110] In step S13, the control device 4 acquires the rotation speed of each Mecanum wheel 21R, 21L via the encoder 22b and determines whether the magnitude (absolute value) of the acquired rotation speed is less than a predetermined first threshold value Δv1. If this determination is NO, the control device 4 advances the control process to step S18 to assist the diagonal movement of the bed 10 instead of executing the second rotation operation. In step S18, the control device 4 determines control parameters such as the drive torque and drive time of each motor 22R, 22L based on various detection signals. Thereafter, the control device 4 operates each motor 22R, 22L based on the determined control parameters to assist the diagonal movement of the bed 10 (step S19).

[0111] On the other hand, if the determination in step S13 is YES, the control device 4 advances the control process to step S14 to execute the second turning operation. In step S14, the control device 4 determines whether the second turning operation is enabled. If this determination is NO (if the second turning operation has been disabled), the control process returns. On the other hand, if the determination in step S14 is YES, the control process advances to step S15.

[0112] In step S15, the control device 4 first calculates the turning angle θ (=ω·t) of the rear wheel 14B in the first turning operation based on the angular velocity ω around the yaw axis Oz detected by the inertial sensor 5 and the operation time t of the first turning operation acquired by a timer built into the control device 4.

[0113] Here, the distance La between the two Mecanum wheels 21R, 21L and the rear end of the bed 10 (e.g., the headboard 11h) in the front-rear direction is stored in advance in the control device 4. Therefore, by combining this distance La with the above-mentioned turning angle θ, it is possible to calculate the movement distance Lb (=La·sinθ) of the bed 10 in the left-right direction (X direction).

[0114] In the following step S16, the control device 4 determines the rotation amount (= number of rotations × operating time) of each of the first and second motors 22R, 22L based on the turning angle θ and the movement distance Lb calculated in step S15. Each rotation amount can be determined based on the number of rotations, operating time, and rotation direction of each motor 22R, 22L. In this determination, reference may be made to the distance from the two Mecanum wheels 21R, 21L to the footboard 11f in the front-to-rear direction, the overall length of the bed 10 in the front-to-rear direction, or the distance from the front wheels 14F to the rear wheels 14B in the front-to-rear direction.

[0115] In the following step S17, the control device 4 executes a second turning operation so as to realize the left and right rotation amounts determined in step S16. In the second turning operation, a turning operation is realized in which one of the left and right rear wheels 14B serves as the center of rotation P2 and the front wheel 14F moves laterally in the predetermined direction At. In this second turning operation, the control device 4 actuates at least one of the two Mecanum wheels 21R, 21L via the motors 22R, 22L so that the magnitude of the turning angle θ of the rear wheel 14B in the first turning operation matches the magnitude of the turning angle of the front wheel 14F in the second turning operation.

[0116] Furthermore, in step S17, the control device 4 reads information indicating whether the bed 10 was moving forward, backward, leftward, or rightward before the start of the first turning operation. This information is stored in the control device 4 as appropriate based on the detection signal of the inertial sensor 5. The control device 4 determines the attitude of the wheels 14c of the front wheels 14F based on the information thus read.

[0117] For example, if the bed 10 has moved forward or backward before the start of the first turning operation, the control device 4 determines that the wheels 14c of the front wheels 14F are oriented vertically (see the upper left and lower right of FIG. 7). If the bed 10 has moved left or right before the start of the first turning operation, the control device 4 determines that the wheels 14c of the front wheels 14F are oriented horizontally (see the upper right of FIG. 7). If the bed 10 has moved diagonally before the start of the first turning operation, the control device 4 determines that the wheels 14c of the front wheels 14F are oriented diagonally (see the lower left of FIG. 7).

[0118] When the wheels 14c are oriented sideways, the front wheels 14F can be moved in the predetermined direction At without adjusting the posture of the wheels 14c. On the other hand, when the wheels 14c are oriented vertically or diagonally, the front wheels 14F start moving in the predetermined direction At after the posture of the wheels 14c is adjusted.

[0119] Therefore, when the wheels 14c are oriented vertically or diagonally, the control device 4 adjusts at least one of the rotation speed and operation time of the motors 22R, 22L. For example, when the wheels 14c are oriented vertically or diagonally, the control device 4 lengthens the operation time compared to when the wheels 14c are oriented horizontally or diagonally. This makes it possible to achieve good assistance regardless of the orientation of the wheels 14c.

[0120] Next, in the processing related to the third turning operation, the control process proceeds to step S21 in Fig. 12. In this step S21, the control device 4 determines whether or not the third turning operation is enabled. If this determination is NO (if the third turning operation has been disabled), the control process returns. On the other hand, if the determination in step S21 is YES, the control process proceeds to step S22.

[0121] In step S22, the control device 4 reads a signal corresponding to the operation input of the operation switch 8 instead of or in addition to the detection signals of the inertial sensor 5, the encoder 22b, and the like.

[0122] In the following step S23, the control device 4 determines, based on the contents read in step S22, whether or not an operation input to the operation switch 8 has been detected. If this determination is NO (if the operation switch 8 has not been operated), the control process returns. On the other hand, if the determination in step S23 is YES, the control process proceeds to step S24.

[0123] In step S24, the control device 4 determines the amount of rotation of each of the first and second motors 22R, 22L. The amount of rotation can be determined based on the rotation speed, operating time, and rotation direction of each of the motors 22R, 22L. Here, the operating time of each of the motors 22R, 22L is determined according to the operating time of the operation switch 8.

[0124] In the following step S25, the control device 4 executes a third turning operation so as to realize the left and right rotation amounts determined in step S24. In the third turning operation, a turn is realized around the person 100 as the center of rotation P3.

[0125] <About lateral movement assistance> According to conventional methods, when a heavy bed 10 weighing 100 kg or more is to be transported, simply applying force to the headboard 11h or the like provided at the rear end of the bed 10 may not be enough to smoothly move the bed 10 sideways, which may cause problems with the assistance provided by the first and second Mecanum wheels 21R, 21L. In this case, to ensure that the assistance provided by the first and second Mecanum wheels 21R, 21L begins, the transporter must go around to the side of the bed 10 and push it sideways.

[0126] However, when moving a patient from the bed 10 to an examination table or operating table, or when moving the patient laterally in a narrow environment such as an elevator, it may be difficult to get around the side of the bed 10, making it difficult to push the bed sideways. In this case, a turning motion is required, which makes it inconvenient to use the assistance of the first and second Mecanum wheels 21R, 21L.

[0127] In contrast, the first and second turning operations according to this embodiment are operations in which the rear wheels 14B and the front wheels 14F are moved in the same predetermined direction At, but are turned in opposite directions, as described with reference to Figure 8. Therefore, by performing the second turning operation after the first turning operation, the tilt of the bed 10 caused by each turning operation can be offset, and the posture of the bed 10 can be kept substantially constant. Here, during the second turning operation, the rear wheels 14B after the lateral movement due to the first turning operation serve as a fulcrum, so the front wheels 14F can be actively moved laterally without further lateral movement of the rear wheels 14B.

[0128] Therefore, by successively performing the first turning operation and the second turning operation, it is possible to move both the front wheels 14F and the rear wheels 14B laterally in the predetermined direction At while suppressing tilting of the bed 10 due to turning. By moving the front wheels 14F and the rear wheels 14B laterally, it is possible to move the entire bed 10 laterally in the predetermined direction At.

[0129] Furthermore, when a force in a predetermined direction At is applied to the rear end of the bed 10, such as the headboard 11h, the two Mecanum wheels 21R, 21L are considered to act as a brake on the lateral movement. In this case, a rotational movement, i.e., a first rotational movement, is performed with the two Mecanum wheels 21R, 21L as fulcrums. In other words, this first rotational movement can be achieved without the person 100 having to go around the side of the bed 10. Therefore, the second rotational movement triggered by the first rotational movement can also be started without moving the person 100. This second rotational movement is performed by operating the Mecanum wheels 21R, 21L via the motors 22R, 22L, so the Mecanum wheels 21R, 21L can start assisting the lateral movement of the person 100 without requiring excessive force from the person 100.

[0130] As described above, according to this embodiment, it is possible to start assisting the lateral movement of the Mecanum wheels 21R, 21L without moving the person 100. Furthermore, since the first turning operation does not require a switch operation, the lateral movement of the bed 10 can be assisted through a more intuitive operation.

[0131] 2, the inertial sensor 5 can be placed between the two Mecanum wheels 21R, 21L, so that the centers of gravity of the two Mecanum wheels 21R, 21L are close to the inertial sensor 5. This allows for accurate detection of the angular velocity around the rotation center P1 when a first turning operation is performed with the centers of gravity of the two Mecanum wheels 21R, 21L as the rotation center P1. This allows for more appropriate assistance of lateral movement.

[0132] 10, by matching the magnitude of the rotation angle between the first rotation operation and the second rotation operation, the tilt of the bed 10 caused by each rotation operation can be accurately offset, which is advantageous in maintaining a substantially constant posture of the bed 10. This allows for more appropriate assistance of lateral movement.

[0133] Furthermore, as illustrated in step S13 of Figure 10, by making a judgment based on the magnitude of the rotation speed, it is possible to properly determine whether the person being transported 100 is requesting lateral movement or diagonal movement, and to more appropriately assist the lateral movement of the bed 10.

[0134] 9, in the third turning operation, a propulsive force is exerted to move the bed 3 laterally in the second predetermined direction Au. Here, when the person 100 is supporting the rear end of the bed 10 (for example, the headboard 11h), exerting the propulsive force as described above realizes an operation of turning the front end of the bed 10 around the person 100 as the fulcrum (center of rotation P3). By using the person 100 positioned behind the bed 10 as the fulcrum, it is possible to assist the lateral movement of the bed 10 without causing the bed 10 to collide with the wall, even when the bed 10 is placed along the wall.

[0135] 10 and step S21 in Fig. 12, the second turning operation and the third turning operation can be individually switched between enabled and disabled, which is advantageous in that it can meet a wide range of needs and also in preventing erroneous operation by the conveyance person 100.

[0136] <Other embodiments> In the above embodiment, a suspension using the tension spring 75 is exemplified, but the present disclosure is not limited to the tension spring 75. For example, the suspension may be configured using a compression spring that expands so as to press the caster 14 against the floor surface.

[0137] In the above embodiment, the rotation amount of each of the first and second motors 22R and 22L is determined based on the rotation angle θ and the movement distance Lb, but the present disclosure is not limited to such a configuration. The following modified examples (1) and (2) may also be used.

[0138] -Modification of the second turning operation (1)- For example, instead of determining the rotation amount of each of the first and second motors 22R and 22L based on the rotation angle θ and the movement distance Lb, the magnitude of each rotation amount may be set to a constant amount. In this case, the sign of each rotation amount (i.e., the direction of rotation) is configured to change depending on whether the rotation angle θ is positive or negative.

[0139] With this configuration, when the second turning operation is performed, the control device 4 will operate the two Mecanum wheels 21R, 21L so that the movement amount of the front wheel 14F in the second turning operation is constant, regardless of the movement distance of the rear wheel 14B in the first turning operation. In this case, when the second turning operation is performed, the transferee 100 can appropriately control the posture of the bed 10 by pushing in the left end of the bed 10 while retracting the right end, or by retracting the left end of the bed 10 while pushing in the right end.

[0140] -Modification of the second turning operation (2)- Fig. 13 is a diagram for explaining a modified example of the second turning operation. As shown in Fig. 13, the transition of the angular velocity around the yaw axis Oz during the first turning operation may be stored in the control device 4, and the motors 22R, 22L may be controlled based on the stored contents.

[0141] In this case, the control device 4 operates the first and second motors 22R and 22L during the second turning operation so as to achieve an angular velocity that is the same as the angular velocity during the first turning operation but with the sign reversed. With this configuration, a suitable second turning operation can be achieved, similar to the above embodiment. [Explanation of symbols]

[0142] 1. Transport auxiliary equipment 14 Caster 14F front wheel 14B rear wheel 2 motorized Mecanum wheels 21R First Mecanum Wheel (Mecanum Wheel) 21L Second Mecanum Wheel (Mecanum Wheel) 22R 1st motor (motor) 22L Second motor (motor) 22b Encoder (second sensor) 4. Control device 5 Inertial sensor (first sensor) 8 Operation switch 10 Medical bed (object) 100 Conveyors At given direction Au Second predetermined direction Oz Yaw axis P1 fulcrum (center of rotation) P2 fulcrum (center of rotation) Δv1 First threshold θ turning angle

Claims

1. A transport assist device that is attached to an object and that is configured to be pushed from the rear side by hand and has a plurality of casters having front and rear wheels, and assists in transporting the object, A plurality of Mecanum wheels attached to a lower surface of the object and disposed forward of the rear wheels; a motor provided on each of the plurality of Mecanum wheels to operate each Mecanum wheel; a first sensor that detects a first turning motion in which the rear wheels move in a predetermined direction along the left-right direction with the plurality of Mecanum wheels as fulcrums; a control device electrically connected to the first sensor and the motor, When the first turning motion is detected by the first sensor, the control device operates at least one of the plurality of Mecanum wheels via the motor to perform a second turning motion in which the front wheel is moved in the predetermined direction around the rear wheel as a fulcrum. A transport auxiliary device characterized by:

2. 2. The transport assist device according to claim 1, The plurality of Mecanum wheels are configured by two Mecanum wheels arranged in a left-right direction of the object, The first sensor is disposed between the two Mecanum wheels and is configured to be able to detect an angular velocity around a yaw axis with respect to the object. A transport auxiliary device characterized by:

3. 3. The transport assist device according to claim 2, the control device calculates a turning angle of the rear wheels in the first turning operation based on the detection result of the first sensor and an operation time of the first turning operation, When the second turning operation is performed, the control device operates at least one of the plurality of Mecanum wheels via the motor so that a magnitude of a turning angle of the rear wheels in the first turning operation and a magnitude of a turning angle of the front wheels in the second turning operation coincide with each other. A transport auxiliary device characterized by:

4. 2. The transport assist device according to claim 1, The two rear wheels are provided along the left-right direction of the object, When the second turning operation is performed, the control device controls the vehicle to turn using one of the two rear wheels located on the leading end side in the predetermined direction as a fulcrum. A transport auxiliary device characterized by:

5. 2. The transport assist device according to claim 1, the control device is electrically connected to an operation switch that receives an operation input for instructing the object to move laterally; When a lateral movement in a second predetermined direction is instructed via the operation switch, the control device actuates at least one of the plurality of Mecanum wheels via the motor to perform a third turning operation that exerts a propulsive force in the second predetermined direction. A transport auxiliary device characterized by:

6. 6. The transport assist device according to claim 5, The control device is configured to be able to individually switch between whether or not the second turning operation is executable and whether or not the third turning operation is executable. A transport auxiliary device characterized by:

7. A medical bed equipped with the transport assist device according to claim 1.

Images