Driving assistance device and driving assistance method

Abstract

A travel assistance device and a travel assistance method are provided that can stably assist the travel of a transport tool without requiring a dedicated operating unit. [Solution] The driving assistance device 100 comprises a drive wheel 103 attached to a body section 101 to drive the body section 101, a support section 102 on which a load L to be transported is loaded on the upper side of the body section 101, a first external force detection section 104 that detects the magnitude of a first vertical external force acting on the support section 102, a second external force detection section 105 that detects the magnitude and direction of a second horizontal external force acting on the support section 102, and a control device 107, and the control device 107 drives the drive wheel 103 with a driving force set based on the first external force so that the body section 101 moves in the direction of the second external force.

Description

[Technical Field]

[0001] The present invention relates to a driving assistance device and a driving assistance method. [Background technology]

[0002] There is known a traveling assistance device that assists the traveling of a transport device, such as a dolly, a transport cart, a mobile bed, or a stretcher, which can be moved in all directions on a floor surface by being manually pushed by an operator and which carries an object to be transported. The traveling assistance device reduces the force required by the operator to operate the transport device by applying a driving force for traveling in accordance with the force applied by the operator (see Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-46890 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-344435 Summary of the Invention [Problem to be solved by the invention]

[0004] For example, the cart in Patent Document 1 includes an external force detector and a control unit provided on the car body, omni-wheel, and handle, and the output torque of the omni-wheel is controlled by a power assist function proportional to the external force detected by the external force detector. However, while this cart is equipped with an omni-wheel that can move in all directions, the operating point is fixed to the handle. In a small space or crowded environment, if the positional relationship between the operator and the handle is restricted, the operator may not be able to access a position where they can operate the handle, which could prevent them from performing the intended operation.

[0005] The bogie in Patent Document 2 includes a car body, Mecanum wheels, support parts, a force sensor that detects an external force acting between the car body and the support parts, and a control unit, and the direction and speed of the car body's movement are controlled based on the magnitude and direction of the external force detected by the force sensor. However, when this bogie is stopped from a running state, particularly if the load is heavy, the support parts may not follow the car body and may cause vibrational movement. Furthermore, this vibrational movement may be recognized as an external force and assistance may be provided based on this, resulting in the problem of vibration dispersion.

[0006] The present invention has been made in consideration of the above, and aims to provide a running assistance device and a running assistance method that can stably assist the running of a transport device without requiring a dedicated operating unit. [Means for solving the problem]

[0007] A driving assistance device according to one embodiment of the present invention comprises a drive wheel attached to a body section to drive the body section, a support section on the upper side of the body section for loading an object to be transported, a first external force detection section that detects the magnitude of a first vertical external force acting on the support section, a second external force detection section that detects the magnitude and direction of a second horizontal external force acting on the support section, and a control device, wherein the control device drives the drive wheel with a drive force set based on the first external force so that the body section moves in the direction of the second external force.

[0008] This allows the travel assistance device to travel in the direction in which the operator applies the second external force without requiring a dedicated operating unit, thereby reducing the burden on the operator. Even without a dedicated operating unit, the operator can directly operate the travel assistance device by grasping any part of the support unit or the transported object loaded on the support unit with their hands. This allows the travel assistance device (transportation equipment) to be moved intuitively without special training. Because of its intuitive operation, it can be used in confined spaces or crowded environments without advanced skills. Furthermore, because travel assistance is performed with a desired driving force, regardless of unintended vibrations generated between the support unit and the vehicle body during acceleration and deceleration, the effects of the second external force caused by acceleration and deceleration can be suppressed, resulting in smooth operation. Furthermore, by adjusting the driving force according to the load weight, it is possible to accommodate changes in the weight of the transported object. For example, by reducing the driving force when the transported object is light, vibrations caused by sudden acceleration and deceleration can be suppressed, and by increasing the driving force when the transported object is heavy, rapid acceleration and deceleration can be achieved.

[0009] In one aspect of the driving assistance device of the present invention, when the control device determines that the magnitude of the second external force is greater than a predetermined threshold, it drives the drive wheels with the driving force so that the vehicle body part moves in the direction of the second external force, and when it determines that the magnitude of the second external force is equal to or less than the predetermined threshold, it maintains the drive state of the drive wheels.

[0010] This allows driving assistance to be performed when a second external force greater than the threshold value is applied as an activation condition, thereby preventing the driving assistance device from unintentionally driving or changing direction due to errors caused by the operator's unintentional input of a small second external force or vibration.

[0011] A driving assistance device according to one embodiment of the present invention comprises drive wheels attached to a body section to drive the body section, a support section on the upper side of the body section for loading an object to be transported, a first external force detection section that detects the magnitude of a first vertical external force acting on the support section, a second external force detection section that detects the magnitude and direction of a second horizontal external force acting on the support section, and a control device, wherein the control device drives the drive wheels so that the body section moves in the direction of the second external force at a predetermined constant speed.

[0012] This allows the travel assistance device to travel in the direction in which the operator applies the second external force without the need for a dedicated operating unit, thereby reducing the burden on the operator. Even without a dedicated operating unit, the operator can directly operate the travel assistance device by grasping any part of the support unit, the transported object loaded on the support unit, etc., with their hands. This allows the travel assistance device (transportation equipment) to be moved intuitively without special training. Because intuitive operation is possible, the device can be used in narrow spaces or crowded environments without advanced skills. Furthermore, because travel assistance is provided at any speed, regardless of unintended vibrations generated between the support unit and the vehicle body during acceleration and deceleration, the effects of the second external force caused by acceleration and deceleration can be suppressed, resulting in smooth operation.

[0013] In one aspect of the driving assistance device of the present invention, the control device accelerates the vehicle body to the speed in the direction of the second external force at an acceleration set based on the first external force, and then drives the drive wheels so that the vehicle body moves at the speed.

[0014] This allows the acceleration to be changed depending on the load weight, for example, by increasing the acceleration when the transported object is light and decreasing the acceleration when the transported object is heavy, thereby alleviating the discomfort felt when accelerating or decelerating even if the weight of the transported object changes.

[0015] In one aspect of the driving assistance device of the present invention, when the control device determines that the magnitude of the second external force is greater than a predetermined threshold, it drives the drive wheels so that the vehicle body part moves in the direction of the second external force at the speed, and when it determines that the magnitude of the second external force is equal to or less than the predetermined threshold, it maintains the drive state of the drive wheels.

[0016] This allows driving assistance to be performed when a second external force greater than the threshold value is applied as an activation condition, thereby preventing the driving assistance device from unintentionally driving or changing direction due to errors caused by the operator's unintentional input of a small second external force or vibration.

[0017] In one aspect of the driving assistance device of the present invention, the first external force detection unit is provided between the support unit and the vehicle body unit, and detects a vertical force applied from the support unit to the vehicle body unit as the first external force.

[0018] This allows the vertical force acting between the support section and the vehicle body section to be measured directly, making it possible to easily detect the weight of the load placed on the support section.

[0019] In a driving assistance device according to one aspect of the present invention, the second external force detection unit is provided between the support unit and the vehicle body unit, and detects a horizontal force acting from the support unit to the vehicle body unit as the second external force.

[0020] This allows the horizontal force acting between the support part and the vehicle body part to be measured directly, making it possible to easily detect the second horizontal external force acting on the support part or the transported object.

[0021] In one aspect of the driving assistance device of the present invention, instead of detecting the second horizontal external force acting on the support part, the second external force detection part detects the torque measured at the drive wheel as a third external force acting on the drive wheel, and the control device calculates the horizontal external force acting on the vehicle body part as the second external force based on the third external force.

[0022] This allows the second external force to be obtained using a torque detection mechanism that is provided in advance near the drive wheels or the drive unit that drives the drive wheels. With this configuration, since the detection point is near the drive wheels, it is not possible to accurately measure the force that is lost when the force is transmitted from the support unit. However, in the present invention, since the vehicle is driven by drive control using an arbitrary drive force or speed control using an arbitrary speed regardless of the magnitude of the second external force, it is possible to suppress the influence of inaccuracies in the detected value due to losses, and sufficient driving assistance can be achieved.

[0023] A driving assistance method according to one aspect of the present invention is a driving assistance method using a driving assistance device that includes drive wheels attached to a body section to cause the body section to drive, a support section on the upper side of the body section for loading a transported object, a first external force detection section that detects the magnitude of a first vertical external force acting on the support section, and a second external force detection section that detects the magnitude and direction of a second horizontal external force acting on the support section, and includes the steps of detecting the magnitude of the first external force, setting a driving force to drive the drive wheels based on the first external force, detecting the magnitude and direction of the second external force, and driving the drive wheels with the set driving force so that the body section moves in the direction of the second external force.

[0024] This allows the travel assistance device to travel in the direction in which the operator applies the second external force without requiring a dedicated operating unit, thereby reducing the burden on the operator. Even without a dedicated operating unit, the operator can directly operate the travel assistance device by grasping any part of the support unit or the transported object loaded on the support unit with their hands. This allows the travel assistance device (transportation equipment) to be moved intuitively without special training. Because of its intuitive operation, it can be used in confined spaces or crowded environments without advanced skills. Furthermore, because travel assistance is performed with a desired driving force, regardless of unintended vibrations generated between the support unit and the vehicle body during acceleration and deceleration, the effects of the second external force caused by acceleration and deceleration can be suppressed, resulting in smooth operation. Furthermore, by adjusting the driving force according to the load weight, it is possible to accommodate changes in the weight of the transported object. For example, by reducing the driving force when the transported object is light, vibrations caused by sudden acceleration and deceleration can be suppressed, and by increasing the driving force when the transported object is heavy, rapid acceleration and deceleration can be achieved.

[0025] A driving assistance method according to one aspect of the present invention further includes the steps of determining whether to change the drive state of the drive wheels based on the magnitude of the second external force, driving the drive wheels so that the vehicle body moves in the direction of the second external force if it is determined that the magnitude of the second external force is greater than a predetermined threshold, and maintaining the drive state of the drive wheels if it is determined that the magnitude of the second external force is equal to or less than the predetermined threshold.

[0026] This allows driving assistance to be performed when a second external force greater than the threshold value is applied as an activation condition, thereby preventing the driving assistance device from unintentionally driving or changing direction due to errors caused by the operator's unintentional input of a small second external force or vibration.

[0027] A driving assistance method according to one aspect of the present invention is a driving assistance method using a driving assistance device that includes drive wheels attached to a body section to drive the body section, a support section on the upper side of the body section for loading a transported object, a first external force detection section that detects the magnitude of a first vertical external force acting on the support section, and a second external force detection section that detects the magnitude and direction of a second horizontal external force acting on the support section, and includes the steps of detecting the magnitude and direction of the second external force, and driving the drive wheels so that the body section moves in the direction of the second external force at a predetermined constant speed.

[0028] This allows the travel assistance device to travel in the direction in which the operator applies the second external force without requiring a dedicated operating unit, thereby reducing the burden on the operator. Even without a dedicated operating unit, the operator can directly operate the travel assistance device by grasping any part of the support unit, such as the support unit or the transported object L loaded on the support unit, with their hands. This allows the operator to intuitively move the travel assistance device (transportation equipment) without special training. Because intuitive operation is possible, the device can be used in narrow spaces or crowded environments without advanced skills. Furthermore, because travel assistance is provided at any speed, regardless of unintended vibrations generated between the support unit and the vehicle body during acceleration and deceleration, the effects of the second external force caused by acceleration and deceleration can be suppressed, resulting in smooth operation.

[0029] A driving assistance method according to one aspect of the present invention further includes the steps of detecting the magnitude of the first external force, setting an acceleration to accelerate to the speed based on the first external force, and accelerating to the speed in the direction of the second external force using the acceleration, and then driving the drive wheels so that the vehicle body moves at the speed.

[0030] This allows the acceleration to be changed depending on the load weight, for example, by increasing the acceleration when the transported object is light and decreasing the acceleration when the transported object is heavy, thereby alleviating the discomfort felt when accelerating or decelerating even if the weight of the transported object changes.

[0031] A driving assistance method according to one aspect of the present invention includes the steps of: determining whether to change the drive state of the drive wheels based on the magnitude of the second external force; driving the drive wheels so that the vehicle body moves in the direction of the second external force at the speed if it is determined that the magnitude of the second external force is greater than a predetermined threshold; and maintaining the drive state of the drive wheels if it is determined that the magnitude of the second external force is equal to or less than the predetermined threshold.

[0032] This allows driving assistance to be performed when a second external force greater than the threshold value is applied as an activation condition, thereby preventing the driving assistance device from unintentionally driving or changing direction due to errors caused by the operator's unintentional input of a small second external force or vibration. [Effects of the Invention]

[0033] According to the present invention, it is possible to provide a driving assistance device and a driving assistance method that can achieve this. [Brief explanation of the drawings]

[0034] [Figure 1] FIG. 1 is a schematic diagram illustrating an example of the configuration of a driving assistance device according to the first embodiment. [Figure 2] FIG. 2 is a flowchart illustrating an example of the operation of the driving assistance device of the first embodiment. [Figure 3] FIG. 3 is a flowchart illustrating an example of the operation of the driving assistance device of the second embodiment. [Figure 4] FIG. 4 is a flowchart illustrating an example of the operation of the driving assistance device of the third embodiment. [Figure 5] FIG. 5 is a schematic diagram illustrating a configuration example of a modified driving assistance device. [Figure 6] FIG. 6 is a perspective view showing an example of the basic configuration of a driving wheel according to a modified example. [Figure 7] FIG. 7 is a front view showing a modified driving wheel. [Figure 8] FIG. 8 is a side view showing a modified driving wheel. [Figure 9] FIG. 9 is a plan view showing a modified driving wheel. [Figure 10] FIG. 10 is a cross-sectional view taken along line AA in FIG. [Figure 11] FIG. 11 is a cross-sectional view taken along the line BB in FIG. [Figure 12] FIG. 12 is a cross-sectional view taken along line CC in FIG. [Figure 13] FIG. 13 is a cross-sectional view taken along line DD in FIG. [Figure 14] FIG. 14 is a schematic diagram showing a driving force transmission path of a modified driving wheel. [Figure 15] FIG. 15 is a block diagram showing an example of the configuration of a modified driving wheel. DETAILED DESCRIPTION OF THE INVENTION

[0035] Modes (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by a person skilled in the art and those that are substantially the same. Furthermore, the components described below can be combined as appropriate.

[0036] (First embodiment) [Device configuration] First, the configuration of a driving assistance device 100 according to the first embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic diagram illustrating an example of the configuration of the driving assistance device 100 according to the first embodiment. Note that in the drawings illustrating the embodiment, components other than those related to the invention are omitted as appropriate. Note that in the following description, one direction within a horizontal plane is defined as the X-axis direction, a direction intersecting the X-axis direction within the horizontal plane is defined as the Y-axis direction, and a direction intersecting both the X-axis direction and the Y-axis direction (i.e., the vertical direction) is defined as the Z-axis direction.

[0037] The travel assistance device 100 is a device that assists the travel of a transport device, such as a dolly, a transport cart, a mobile bed, or a stretcher, on which a transported object L is placed and which can be moved in all directions on a floor surface by being manually pushed by an operator. Note that while the travel assistance device 100 in the first embodiment is the dolly itself, in this embodiment it may be a device that is detachably connected to the transport device on which the transported object L is placed. The travel assistance device 100 in the first embodiment includes a vehicle body 101, which is the dolly main body, a support unit 102, four drive wheels 103, a first external force detection unit 104, a second external force detection unit 105, a power supply unit 106, and a control device 107.

[0038] The body 101 is, for example, a flat plate material and has a rectangular shape in a plan view. A support 102 is provided on the upper surface of the body 101. The support 102 has a flat surface on which a load L can be placed. The travel assistance device 100 can be configured as a traveling device by placing equipment along the flat surface of the support 102. Examples of such equipment include a hand lifter, a forklift, a picking robot, and medical equipment.

[0039] The body 101 has four drive wheels 103 attached to the four corners on its rear side. The four drive wheels 103 are rotatable and steerable. The number and arrangement of the drive wheels 103 of the driving assist device 100 are not limited to the above-described configuration. For example, in the four-wheel configuration described above, the driving assist device 100 may have a pair of drive wheels 103 attached to the rear side of the driving assist device 100 and a pair of driven wheels attached to the front side of the driving assist device 100. Furthermore, although not shown in the drawings, in a configuration with three or more wheels, the driving assist device 100 may have one drive wheel 103 and all the other wheels may be driven wheels. Furthermore, although not shown in the drawings, in a configuration with three or more wheels, the driving assist device 100 may have no driven wheels and all the wheels may be drive wheels 103. In other words, in a configuration with three or more wheels, the driving assist device 100 may have at least one drive wheel 103.

[0040] A first external force detection unit 104 and a second external force detection unit 105 are provided between the vehicle body unit 101 and the support unit 102. The first external force detection unit 104 detects an external force in the vertical direction (Z direction) (referred to as a "first external force" in this specification) applied from the support unit 102 to the vehicle body unit 101. In other words, the first external force detection unit 104 detects the weight of the load L placed on the support unit 102. The first external force detection unit 104 includes, for example, a load sensor. The first external force detection unit 104 outputs the detection result to the control device 107.

[0041] The second external force detection unit 105 detects an external force (referred to herein as a "second external force") in the horizontal direction (XY direction) applied from the support unit 102 to the body unit 101. The second external force detection unit 105 detects a second external force applied to the support unit 102 by the operator. When the operator directly operates an arbitrary part of the load L or the like loaded on the support unit 102 by grabbing it with their hands, the second external force detection unit 105 detects the second external force applied to the support unit 102 by the operator via that arbitrary part. When the operator operates the support unit 102 from separate parts with both hands, or when multiple operators operate the support unit 102 from multiple parts, the second external force detection unit 105 detects the second external force, which is the resultant force of the horizontal external forces applied to the support unit 102 via those parts. The second external force detection unit 105 includes, for example, a load cell. Second external force detection unit 105 includes, for example, a plurality of load cells that detect the magnitude of forces acting in each of the X-axis direction and the Y-axis direction, detects a resultant force as a second external force, and detects the direction of the resultant force as the direction of the second external force. Second external force detection unit 105 outputs the detection result to control device 107. Note that, although first external force detection unit 104 and second external force detection unit 105 are described separately in the first embodiment, a six-axis force sensor or the like that detects both a first external force in the vertical direction and a second external force in the horizontal direction may also be used.

[0042] Furthermore, a power supply unit 106 and a control device 107 are mounted on the rear surface of the vehicle body 101 between the front and rear drive wheels 103. The control device 107 includes a computer system. The computer system includes a processing unit having a processor such as a CPU (Central Processing Unit), a storage device having memory such as a read-only memory or a random access memory, and hardware resources such as an input / output interface device. Therefore, in the driving assistance device 100, the control device 107 controls the driving wheels 103. In other words, the driving assistance device 100 can be configured as an automatic guided vehicle (AGV).

[0043] The control device 107 drives the drive units corresponding to the four drive wheels 103 based on a predetermined program, for example, to move the body 101 in any direction. The control device 107 can acquire the magnitude of the first external force acting in the vertical direction on the support unit 102 from the first external force detection unit 104 as the weight of the load L to be transported loaded on the support unit 102. The control device 107 changes the drive force applied to the drive wheels 103 based on the magnitude of the first external force acting in the vertical direction on the support unit 102.

[0044] For example, the control device 107 determines whether the weight of the load L is greater than or equal to a first threshold value W L Second threshold W H If the first threshold value W is less than the first threshold value W, the drive unit is controlled in the standard mode. L is 100 kg, and the second threshold W H The control device 107 may, for example, determine whether the weight of the load L is greater than the first threshold value W L If the weight of the load L is lighter, the control device 107 controls the drive unit in a light mode in which the torque control value is lower than that in the standard mode. H If the load is heavier, the drive unit is controlled in a heavy mode with a higher torque control value than in the standard mode.

[0045] The control device 107 can acquire the magnitude and direction of the second horizontal external force acting on the support part 102 from the second external force detection unit 105. When the magnitude of the second external force acting on the support part 102 detected by the second external force detection unit 105 is greater than a predetermined threshold, the control device 107 applies a driving force in the direction of the second external force acting on the support part 102. At this time, the applied driving force is a driving force corresponding to a mode set based on the weight of the load L to be transported from among the standard mode, light weight mode, and heavy weight mode.

[0046] The control device 107 maintains the original output state when the magnitude of the second external force acting on the support part 102 detected by the second external force detection unit 105 is equal to or smaller than a predetermined threshold. When a second external force greater than the threshold is applied to the support part 102 of the running assist device 100 in a stationary state, a driving force is applied in the direction in which the second external force is applied. When a second external force greater than the threshold is applied in one direction to the support part 102 of the running assist device 100 while it is traveling in one direction, the direction in which the second external force is applied does not change, and the direction in which the driving force is applied is also maintained. When a second external force greater than the threshold is applied in an intersecting direction to the support part 102 of the running assist device 100 while it is traveling in one direction, the direction in which the driving force is applied is changed to the intersecting direction. When a second external force in the opposite direction is applied to the support part 102 of the running assist device 100 while it is traveling in one direction, a driving force in the opposite direction is applied, causing the running assist device 100 to decelerate and stop.

[0047] [Control method] Next, the operation of the driving assistance device 100 according to the first embodiment will be described. Fig. 2 is a flowchart showing an example of the operation of the driving assistance device 100 according to the first embodiment. The processing shown in Fig. 2 is executed by the control device 107 of the driving assistance device 100 based on a predetermined control program and data. For example, when power is supplied from the power supply unit 106 or when the driving assistance device 100 receives a predetermined operation for starting driving assistance operation, the control device 107 proceeds to step S201 shown in Fig. 2 and starts the processing.

[0048] In step S201, the control device 107 of the driving assistance device 100 performs a determination process on the load weight. Specifically, the first external force detection unit 104 detects the weight of the transported object L loaded on the support unit 102 and outputs the detection result to the control device 107. The control device 107 acquires the weight of the transported object L detected by the first external force detection unit 104. The control device 107 determines whether the weight of the transported object L is greater than or equal to a first threshold value W L Lighter or first threshold W L Second threshold W H Is it equal to or less than the second threshold W? H First threshold W L and the second threshold W H is a fixed value that is set in advance.

[0049] The control device 107 determines whether the weight of the load L is greater than the first threshold value W L If it is determined that the load is lighter (step S201; load weight <W L ), and in step S202, the lightweight mode is set. The control device 107 determines whether the weight of the load L is greater than the first threshold value W L Second threshold W H If it is determined that the following is true (step S201; W L ≦Load weight≦W H ), and in step S203, the control device 107 sets the standard mode. H If it is determined that the load weight is heavier (step S201; load weight > W H ), and in step S204, the weight mode is set. After executing any one of step S202, step S203, and step S204, the control device 107 proceeds to step S210.

[0050] In step S210, the control device 107 starts driving assistance control. More specifically, the control device 107 starts control to assist the driving of the driving assistance device 100 with a driving force corresponding to the mode set in any one of steps S202, S203, and S204.

[0051] In step S211, the driving assist device 100 detects the magnitude and direction of a second external force acting in the horizontal direction on the support part 102. Specifically, the second external force detection unit 105 detects the magnitude and direction of a second external force acting in the X and Y directions on the support part 102 relative to the vehicle body part 101, and outputs the detection result to the control device 107. The control device 107 acquires the magnitude and direction of the second external force acting in the horizontal direction detected by the second external force detection unit 105.

[0052] In step S212, the control device 107 performs a determination process on the magnitude of the second external force acquired in step S211. Specifically, the control device 107 determines whether the magnitude of the second external force is greater than a predetermined threshold. If the control device 107 determines that the magnitude of the second external force is greater than the predetermined threshold (step S212; Yes), the control device 107 proceeds to step S213 and changes the drive state of the drive wheels 103. If the control device 107 determines that the magnitude of the second external force is equal to or less than the predetermined threshold (step S212; No), the control device 107 proceeds to step S214 and maintains the drive state of the drive wheels 103.

[0053] In step S213, the control device 107 controls the drive units corresponding to the four drive wheels 103 so as to drive in the direction of the second external force detected in step S211 with a drive force corresponding to the mode set in any one of steps S202, S203, and S204. The control device 107 controls the rotational torque applied to the four drive wheels 103.

[0054] That is, when the support part 102 is pushed from a predetermined direction, the entire running assist device 100 moves, and in step S211, the second external force detection part 105 detects the direction in which the second external force is received. In step S213, a driving force corresponding to the set mode is generated in the direction in which the support part 102 receives the second external force, and the running assist device 100 runs, thereby reducing the force with which the operator pushes the running assist device 100 as a cart.

[0055] Furthermore, when the support part 102 of the driving assist device 100 is pushed in the opposite direction to the driving direction while the driving assist device 100 is moving, the entire driving assist device 100 decelerates, and in step S211, the second external force detection part 105 detects the direction in which the second external force is received. In step S213, a driving force corresponding to the set mode is generated in the direction in which the support part 102 receives the second external force, and the driving assist device 100 is braked, thereby reducing the force required by the operator to stop the driving assist device 100 as a cart.

[0056] Step S213 is a step that is executed when the driving assistance device 100 transitions from a stationary state to a driving state, when the driving direction is changed, or when the driving state is changed to a braking and stationary state.

[0057] In step S214, the control device 107 maintains the original drive state. For example, when the driving assistance device 100 is stationary, the control device 107 controls the drive units corresponding to the four drive wheels 103 so that the driving assistance device 100 maintains the stationary state. For example, when the driving assistance device 100 is traveling in a predetermined direction, the control device 107 controls the drive units corresponding to the four drive wheels 103 so that the driving assistance device 100 maintains traveling with a drive force corresponding to the currently set mode.

[0058] The control device 107 repeatedly executes the processes from step S211 to step S214. For example, when the supply of power from the power supply unit 106 is stopped or when the driving assistance device 100 receives a predetermined operation for ending the driving assistance operation, the control device 107 exits the loop process from step S210 to step S215 and ends the process of the flowchart shown in FIG.

[0059] As described above, the driving assistance device 100 of the first embodiment comprises a drive wheel 103 attached to the body section 101 to drive the body section 101, a support section 102 on which the load L to be transported is loaded on the upper side of the body section 101, a first external force detection section 104 that detects the magnitude of a first vertical external force applied to the support section 102, a second external force detection section 105 that detects the magnitude and direction of a second horizontal external force applied to the support section 102, and a control device 107, and the control device 107 drives the drive wheel 103 with a driving force set based on the first external force so that the body section 101 moves in the direction of the second external force.

[0060] This allows the operator to assist the driving assist device 100 in driving in the direction in which the operator applies the second external force, without requiring a dedicated operating unit, thereby reducing the burden on the operator. Even without a dedicated operating unit, the operator can directly operate the driving assist device 100 by grasping any part of the support unit 102, such as the support unit 102 or the object L loaded on the support unit 102, with their hands. This allows the driving assist device 100 (cart) to be moved intuitively without special training. Because of the intuitive operation, the driving assist device 100 can be used in narrow spaces or crowded environments without requiring advanced skills. Furthermore, since driving assistance is performed with a desired driving force, regardless of unintended vibrations generated between the support unit 102 and the vehicle body 101 during acceleration and deceleration, the effects of the second external force caused by acceleration and deceleration can be suppressed, resulting in smooth operation. Furthermore, by adjusting the driving force according to the load weight, it is possible to accommodate changes in the weight of the object L, for example, by reducing the driving force when the object L is light, thereby suppressing vibrations caused by sudden acceleration and deceleration, and by increasing the driving force when the object L is heavy, thereby achieving rapid acceleration and deceleration.

[0061] Furthermore, in the driving assistance device 100 of the first embodiment, when the control device 107 determines that the magnitude of the second external force is greater than a predetermined threshold, it drives the driving wheels 103 with a driving force so that the body part 101 moves in the direction of the second external force, and when it determines that the magnitude of the second external force is equal to or less than the predetermined threshold, it maintains the driving state of the driving wheels 103.

[0062] As a result, driving assistance is performed using a second external force greater than the threshold as an activation condition, so that the driving assistance device 100 can be prevented from unintentionally driving or changing direction due to errors caused by the operator's unintentional input of a small second external force or vibration.

[0063] Furthermore, in the driving assistance device 100 of the first embodiment, the first external force detection unit 104 is provided between the support unit 102 and the vehicle body unit 101, and detects the vertical force applied from the support unit 102 to the vehicle body unit 101 as the first external force.

[0064] This allows the vertical force acting between the support part 102 and the vehicle body part 101 to be measured directly, so that the weight of the load L placed on the support part 102 can be easily detected.

[0065] In addition, in the driving assistance device 100 of the first embodiment, the second external force detection unit 105 is provided between the support unit 102 and the vehicle body unit 101, and detects the horizontal force applied from the support unit 102 to the vehicle body unit 101 as the second external force.

[0066] This allows the horizontal force acting between the support part 102 and the vehicle body part 101 to be measured directly, so that the horizontal force acting on the support part 102 and the load L can be easily detected.

[0067] Furthermore, the driving assistance method of the first embodiment is a driving assistance method using a driving assistance device 100 that includes a drive wheel 103 attached to the body section 101 to drive the body section 101, a support section 102 that carries the load L on the upper side of the body section 101, a first external force detection section 104 that detects the magnitude of a first vertical external force acting on the support section 102, and a second external force detection section 105 that detects the magnitude and direction of a second horizontal external force acting on the support section 102, and includes the steps of detecting the magnitude of the first external force, setting a driving force to drive the drive wheel 103 based on the first external force, detecting the magnitude and direction of the second external force, and driving the drive wheel 103 with the driving force so that the body section 101 moves in the direction of the second external force with the set driving force.

[0068] This allows the operator to assist the driving assist device 100 in driving in the direction in which the operator applies the second external force, without requiring a dedicated operating unit, thereby reducing the burden on the operator. Even without a dedicated operating unit, the operator can directly operate the driving assist device 100 by grasping any part of the support unit 102, such as the support unit 102 or the object L loaded on the support unit 102, with their hands. This allows the driving assist device 100 (cart) to be moved intuitively without special training. Because of the intuitive operation, the driving assist device 100 can be used in narrow spaces or crowded environments without requiring advanced skills. Furthermore, since driving assistance is performed with a desired driving force, regardless of unintended vibrations generated between the support unit 102 and the vehicle body 101 during acceleration and deceleration, the effects of the second external force caused by acceleration and deceleration can be suppressed, resulting in smooth operation. Furthermore, by adjusting the driving force according to the load weight, it is possible to accommodate changes in the weight of the object L, for example, by reducing the driving force when the object L is light, thereby suppressing vibrations caused by sudden acceleration and deceleration, and by increasing the driving force when the object L is heavy, thereby achieving rapid acceleration and deceleration.

[0069] In addition, the driving assistance method of the first embodiment further includes a step of determining whether to change the drive state of the drive wheels 103 based on the magnitude of the second external force; a step of driving the drive wheels 103 so that the body part 101 moves in the direction of the second external force if it is determined that the magnitude of the second external force is greater than a predetermined threshold; and a step of maintaining the drive state of the drive wheels 103 if it is determined that the magnitude of the second external force is equal to or less than the predetermined threshold.

[0070] As a result, driving assistance is performed using a second external force greater than the threshold as an activation condition, so that the driving assistance device 100 can be prevented from unintentionally driving or changing direction due to errors caused by the operator's unintentional input of a small second external force or vibration.

[0071] (Second embodiment) Next, a description will be given of a driving assistance device 100 according to a second embodiment. The driving assistance device 100 according to the second embodiment is different from the driving assistance device 100 according to the first embodiment in the driving assistance method performed by the control device 107. Specifically, while the control device 107 according to the first embodiment performs torque control to drive the driving wheels 103 with a driving force corresponding to each mode based on the load weight, the control device 107 according to the second embodiment performs speed control to drive the driving wheels 103 so as to travel at a predetermined speed.

[0072] The control device 107 controls the drive units at a preset target speed value. The target speed value is a fixed value. That is, like the control device 107 of the first embodiment, the control device 107 of the second embodiment can acquire the magnitude and direction of the second horizontal external force acting on the support unit 102 from the second external force detection unit 105. When the magnitude of the second external force acting on the support unit 102 detected by the second external force detection unit 105 is greater than a predetermined threshold, the control device 107 of the second embodiment drives the drive units corresponding to the four drive wheels 103 so that the vehicle travels at a constant speed in the direction of the second external force acting on the support unit 102.

[0073] The control device 107 maintains the original speed state when the magnitude of the second external force acting on the support part 102 detected by the second external force detection unit 105 is equal to or smaller than a predetermined threshold. When a second external force greater than the threshold is applied to the support part 102 of the running assistance device 100 in a stationary state, the control device controls the drive unit to run at a predetermined speed in the direction in which the second external force was applied. When a second external force greater than the threshold is applied in one direction to the support part 102 of the running assistance device 100 while the running assistance device 100 is running in one direction, the direction in which the second external force is applied does not change, and the running direction is also maintained. When a second external force greater than the threshold is applied in an intersecting direction to the support part 102 of the running assistance device 100 while the running assistance device 100 is running in one direction, the running direction is changed to the intersecting direction. Note that when the angle between the direction of the second external force (intersecting direction) and the running direction (one direction) is within a predetermined angle range, the control device 107 determines that deceleration or stopping is being attempted, and controls to decelerate without changing the running direction to the direction of the second external force. The predetermined angle is, for example, 160 degrees or more and 200 degrees or less.

[0074] [Control method] Next, the operation of the driving assistance device 100 according to the second embodiment will be described. Fig. 3 is a flowchart showing an example of the operation of the driving assistance device 100 according to the second embodiment. The processing shown in Fig. 3 is executed by the control device 107 of the driving assistance device 100 based on a predetermined control program and data. For example, when power is supplied from the power supply unit 106 or when the driving assistance device 100 receives a predetermined operation for starting driving assistance operation, the control device 107 proceeds to step S310 shown in Fig. 3 and starts the processing.

[0075] In step S310, the control device 107 starts driving assistance control. More specifically, the control device 107 starts control to assist the driving of the driving assistance device 100 at a preset target speed.

[0076] The process of detecting the magnitude and direction of the second horizontal external force acting on the support part 102 in step S311, and the process of determining the magnitude of the second external force in step S312 are similar to steps S211 and S212 of the first embodiment shown in Figure 2, so their explanations are omitted.

[0077] In step S313, the control device 107 controls the drive units corresponding to the four drive wheels 103 so that the vehicle accelerates to a target speed in the direction of the second external force detected in step S311 and then travels at a constant speed.

[0078] That is, when the support part 102 is pushed from a predetermined direction, the entire running assist device 100 moves, and in step S311, the second external force detection part 105 detects the direction in which the second external force is received. In step S313, the running assist device 100 runs at a constant speed in the direction in which the support part 102 receives the second external force, thereby reducing the force with which the operator pushes the running assist device 100 as a cart.

[0079] Step S313 is a step that is executed when the driving assistance device 100 transitions from a stationary state to a driving state or when the driving direction is changed.

[0080] In step S314, the control device 107 maintains the original state. For example, when the driving assistance device 100 is stationary, the control device 107 controls the drive units corresponding to the four drive wheels 103 so that the driving assistance device 100 maintains the stationary state. For example, when the driving assistance device 100 is traveling in a predetermined direction, the control device 107 controls the drive units corresponding to the four drive wheels 103 so that the driving assistance device 100 continues traveling in the predetermined direction.

[0081] The control device 107 repeatedly executes the processes from step S311 to step S314. For example, when the supply of power from the power supply unit 106 is stopped or when the driving assistance device 100 receives a predetermined operation for ending the driving assistance operation, the control device 107 exits the loop process from step S310 to step S315 and ends the process of the flowchart shown in FIG.

[0082] As described above, the second embodiment of the driving assistance device 100 comprises a drive wheel 103 attached to the body section 101 to drive the body section 101, a support section 102 on which the load L to be transported is loaded on the upper surface side of the body section 101, a first external force detection section 104 that detects the magnitude of a first vertical external force acting on the support section 102, a second external force detection section 105 that detects the magnitude and direction of a second horizontal external force acting on the support section 102, and a control device 107, and the control device 107 drives the drive wheel 103 so that the body section 101 moves in the direction of the second external force at a predetermined constant speed.

[0083] This allows the operator to assist the driving assist device 100 in driving in the direction in which the operator applies the second external force, without the need for a dedicated operating unit, thereby reducing the burden on the operator. Even without a dedicated operating unit, the operator can directly operate the driving assist device 100 by grasping any part of the support unit 102, such as the support unit 102 or the load L loaded on the support unit 102, with their hands. This allows the operator to intuitively move the driving assist device 100 (cart) without special training to operate the driving assist device 100. Because intuitive operation is possible, the driving assist device 100 can be applied to operation in narrow spaces or crowded environments without advanced skills. Furthermore, driving assistance is provided at any speed regardless of vibrations unintended by the operator that occur between the support unit 102 and the vehicle body unit 101 during acceleration and deceleration, so the effects of the second external force caused by acceleration and deceleration can be suppressed, allowing for smooth operation.

[0084] In addition, in the driving assistance device 100 of the second embodiment, if the control device 107 determines that the magnitude of the second external force is greater than a predetermined threshold, it drives the drive wheels 103 so that the body part 101 moves at a speed in the direction of the second external force, and if it determines that the magnitude of the second external force is equal to or less than the predetermined threshold, it maintains the drive state of the drive wheels 103.

[0085] As a result, driving assistance is performed using a second external force greater than the threshold as an activation condition, so that the driving assistance device 100 can be prevented from unintentionally driving or changing direction due to errors caused by the operator's unintentional input of a small second external force or vibration.

[0086] In addition, the second embodiment of the driving assistance method is a driving assistance method using a driving assistance device 100 that includes a drive wheel 103 attached to the body section 101 to drive the body section 101, a support section 102 that carries the load L on the upper side of the body section 101, a first external force detection section 104 that detects the magnitude of a first vertical external force acting on the support section 102, and a second external force detection section 105 that detects the magnitude and direction of a second horizontal external force acting on the support section 102, and includes a step of detecting the magnitude and direction of the second external force, and a step of driving the drive wheel 103 so that the body section 101 moves in the direction of the second external force at a predetermined constant speed.

[0087] This allows the operator to assist the driving assist device 100 in driving in the direction in which the operator applies the second external force, without the need for a dedicated operating unit, thereby reducing the burden on the operator. Even without a dedicated operating unit, the operator can directly operate the driving assist device 100 by grasping any part of the support unit 102, such as the support unit 102 or the load L loaded on the support unit 102, with their hands. This allows the operator to intuitively move the driving assist device 100 (cart) without special training to operate the driving assist device 100. Because intuitive operation is possible, the driving assist device 100 can be applied to operation in narrow spaces or crowded environments without advanced skills. Furthermore, driving assistance is provided at any speed regardless of vibrations unintended by the operator that occur between the support unit 102 and the vehicle body unit 101 during acceleration and deceleration, so the effects of the second external force caused by acceleration and deceleration can be suppressed, allowing for smooth operation.

[0088] In addition, the driving assistance method of the second embodiment includes a step of determining whether to change the drive state of the drive wheels 103 based on the magnitude of the second external force; a step of driving the drive wheels 103 so that the body part 101 moves at a speed in the direction of the second external force if it is determined that the magnitude of the second external force is greater than a predetermined threshold; and a step of maintaining the drive state of the drive wheels 103 if it is determined that the magnitude of the second external force is equal to or less than the predetermined threshold.

[0089] As a result, driving assistance is performed using a second external force greater than the threshold as an activation condition, so that the driving assistance device 100 can be prevented from unintentionally driving or changing direction due to errors caused by the operator's unintentional input of a small second external force or vibration.

[0090] (Third embodiment) Next, a description will be given of a driving assistance device 100 according to a third embodiment. The driving assistance device 100 according to the third embodiment is different from the driving assistance devices 100 according to the first and second embodiments in the driving assistance method provided by the control device 107. Specifically, similar to the second embodiment, the control device 107 according to the third embodiment drives the drive wheels 103 by speed control so as to drive at a predetermined speed. In addition, the control device 107 according to the third embodiment changes the acceleration until the target speed is reached based on the weight of the load L to be carried.

[0091] For example, the control device 107 determines whether the weight of the load L is greater than or equal to a first threshold value W L Second threshold W H If the first threshold value W is less than or equal to the first threshold value W, the drive unit is controlled to accelerate or decelerate in the standard mode. L is 100 kg, and the second threshold W H The control device 107 may, for example, determine whether the weight of the load L is greater than the first threshold value W L If the weight of the load L is lighter, the drive unit is controlled in a light mode in which the acceleration is greater than that in the standard mode. H If the object is heavier, the drive unit is controlled in a heavy mode in which the acceleration is slower than in the standard mode. Note that the acceleration until the target speed is reached does not have to be constant.

[0092] [Control method] Next, the operation of the driving assistance device 100 according to the third embodiment will be described. Fig. 4 is a flowchart showing an example of the operation of the driving assistance device 100 according to the third embodiment. The processing shown in Fig. 4 is executed by the control device 107 of the driving assistance device 100 based on a predetermined control program and data. For example, when power is supplied from the power supply unit 106 or when the driving assistance device 100 receives a predetermined operation for starting driving assistance operation, the control device 107 proceeds to step S401 shown in Fig. 4 and starts the processing.

[0093] The load weight determination process in step S401, the setting process to light mode in step S402, the setting process to standard mode in step S403, and the setting process to heavy mode in step S404 are the same as steps S201 to S204 in the first embodiment shown in Figure 2, so their explanations will be omitted.

[0094] In step S410, the control device 107 starts driving assistance control. More specifically, the control device 107 starts control to assist the driving of the driving assistance device 100 at a preset target speed. At this time, the control device 107 controls driving until the target speed is reached at an acceleration corresponding to the mode set in any one of steps S202, S203, and S204.

[0095] The process of detecting the magnitude and direction of the second horizontal external force acting on the support part 102 in step S411, and the process of determining the magnitude of the second external force in step S412 are similar to steps S211 and S212 of the first embodiment shown in Figure 2, and steps S311 and S312 of the second embodiment shown in Figure 3, so their explanations will be omitted.

[0096] In step S413, the control device 107 controls the drive units corresponding to the four drive wheels 103 to accelerate to the target speed in the direction of the second external force detected in step S311 at an acceleration corresponding to the mode set in any one of steps S402, S403, and S404, and then travel at a constant speed.

[0097] That is, when the support part 102 is pushed from a predetermined direction, the entire running assist device 100 moves, and in step S411, the second external force detection part 105 detects the direction in which the second external force is received. In step S413, the support part 102 accelerates in the direction in which the second external force is received at an acceleration corresponding to the set mode, and then the running assist device 100 runs at a constant speed, thereby reducing the force with which the operator pushes the running assist device 100 as a cart.

[0098] Step S413 is a step that is executed when the driving assistance device 100 transitions from a stationary state to a driving state or when the driving direction is changed.

[0099] In step S414, the control device 107 maintains the original state. For example, when the driving assistance device 100 is stationary, the control device 107 controls the drive units corresponding to the four drive wheels 103 so that the driving assistance device 100 maintains the stationary state. For example, when the driving assistance device 100 is traveling in a predetermined direction, the control device 107 controls the drive units corresponding to the four drive wheels 103 so that the driving assistance device 100 continues traveling in the predetermined direction.

[0100] The control device 107 repeatedly executes the processing from step S411 to step S414. For example, when the supply of power from the power supply unit 106 is stopped or when the driving assistance device 100 receives a predetermined operation for ending the driving assistance operation, the control device 107 exits the loop processing from step S410 to step S415 and ends the processing of the flowchart shown in FIG.

[0101] As described above, in addition to the configuration of the driving assistance device 100 of the second embodiment, the driving assistance device 100 of the third embodiment has the control device 107 accelerating to a speed in the direction of the second external force at an acceleration set based on the first external force, and then driving the drive wheels 103 so that the body part 101 moves at the speed.

[0102] This allows the acceleration to be changed depending on the load weight, for example, by increasing the acceleration when the load L is light and decreasing the acceleration when the load L is heavy, thereby alleviating the discomfort felt when accelerating or decelerating even if the weight of the load L changes.

[0103] Furthermore, in addition to the steps of the driving assistance method of the second embodiment, the driving assistance method of the third embodiment further includes the steps of detecting the magnitude of the first external force, setting an acceleration to accelerate to a speed based on the first external force, and accelerating to the speed in the direction of the second external force with the acceleration, and then driving the drive wheels 103 so that the body part 101 moves at the speed.

[0104] This allows the acceleration to be changed depending on the load weight, for example, by increasing the acceleration when the load L is light and decreasing the acceleration when the load L is heavy, thereby alleviating the discomfort felt when accelerating or decelerating even if the weight of the load L changes.

[0105] (Variation) [Device configuration] Next, the configuration of a driving assistance device 100A according to a modified example will be described with reference to Figs. 5 to 15. Fig. 5 is a schematic diagram illustrating an example configuration of the driving assistance device 100A according to the modified example. In the driving assistance device 100A according to the modified example shown in Fig. 5, the same components as those of the driving assistance device 100 according to the first embodiment shown in Fig. 1 are denoted by the same reference numerals, and description thereof will be omitted. The driving assistance device 100A according to the modified example includes a vehicle body 101 which is a bogie body, a support unit 102, four drive wheels 103, a first external force detection unit 104, a third external force detection unit 105A, a power supply unit 106, and a control device 107A.

[0106] The third external force detection unit 105A of the modified example detects an external force (referred to as a "third external force" in this specification) acting on the drive wheel 103. In the modified example, the third external force detection unit 105A detects the torque (voltage value) of the drive wheel 103 measured by a torque measurement unit 28 (28A, 28B) described below as the third external force acting on the drive wheel 103. The third external force acting on the drive wheel 103 is an external force applied to the support unit 102 by the operator and transmitted via the vehicle body unit 101. The third external force detection unit 105A outputs the detection result to the control device 107A.

[0107] The control device 107A calculates a second external force indicating an external force in the horizontal direction (XY direction) acting on the entire driving assist device 100A based on the third external force acting on each of the four drive wheels 103 obtained from the third external force detection unit 105A. More specifically, the control device 107A calculates the magnitude and direction of the second external force based on the force acting on the drive units 23 (23A, 23B) described below and the turning angle of the axis O1 (see FIG. 7 described below, etc.), which is the orientation of the drive wheels 103. The force acting on the drive units 23 is detected by strain gauges 30 (30Aa, 30Ab, 30Ba, 30Bb) of the torque measurement units 28 (28A, 28B) described below. The turning angle of the axis O1 is detected by the turning position detection unit 50 described below. That is, the driving assistance device 100A of the modified example differs from the driving assistance device 100 of each embodiment in the method of detecting the second external force in the horizontal direction (XY direction).

[0108] The control method for driving assistance by the control device 107A may be either the torque control of the first embodiment or the speed control of the second and third embodiments.

[0109] [Drive wheel details] The drive wheel 103 will be described in detail below. Fig. 6 is a perspective view showing an example of the basic configuration of a modified drive wheel 103. Fig. 7 is a front view showing a modified drive wheel 103. Fig. 8 is a side view showing a modified drive wheel 103. Fig. 9 is a plan view showing a modified drive wheel 103. Fig. 10 is a cross-sectional view taken along line AA in Fig. 7. Fig. 11 is a cross-sectional view taken along line BB in Fig. 8. Fig. 12 is a cross-sectional view taken along line CC in Fig. 9. Fig. 13 is a cross-sectional view taken along line DD in Fig. 8.

[0110] The drive wheel 103 has a main body 10 fixed to the body part 101 of the driving assistance device 100A as described above, and based on this main body 10, a drive mechanism 11, a turning part 12, a transmission mechanism 13, a power conversion mechanism 14, and a wheel 15 are provided.

[0111] The main body 10 is formed in the shape of a plate with its plate surfaces facing up and down. The drive mechanism 11 inputs rotational force and is mainly provided above the main body 10. The swivel unit 12 is located below the main body 10. The transmission mechanism 13 transmits the rotational force input by the drive mechanism 11. The power conversion mechanism 14 transmits the rotational force of the transmission mechanism 13 to the wheels 15. The wheels 15 are rotatable by the rotational force input via the drive mechanism 11, the transmission mechanism 13, and the power conversion mechanism 14, and can be steered by the swivel unit 12.

[0112] The drive mechanism 11 includes a first belt drive mechanism 22A and a second belt drive mechanism 22B. The first belt drive mechanism 22A includes a first drive unit 23A, a first drive pulley 24A, a first input shaft 25A, a first driven pulley 26A, and a first drive belt 27A. The first drive unit 23A is configured with a motor. The first drive unit 23A is fixed to the main body 10. The first drive unit 23A has a drive shaft 23Aa that protrudes above the main body 10 and extends in the vertical direction. The first drive pulley 24A is fixed to the drive shaft 23Aa. The first input shaft 25A extends in the vertical direction parallel to the drive shaft 23Aa and is supported on the main body 10 so as to be rotatable about an axis O1. The first driven pulley 26A is fixed to the portion of the first input shaft 25A that protrudes above the main body 10. The first driven pulley 26A and the first driving pulley 24A are arranged side by side in a direction perpendicular to the first input shaft 25A and the driving shaft 23Aa. The first driving belt 27A is formed in an annular shape and is wound around the first driven pulley 26A and the first driving pulley 24A. Therefore, in the first belt driving mechanism 22A, the first driving pulley 24A is rotated by the driving of the first driving unit 23A, and this rotation is transmitted from the first driving pulley 24A to the first driven pulley 26A via the first driving belt 27A, thereby rotating the first input shaft 25A.

[0113] The second belt drive mechanism 22B includes a second drive unit 23B, a second drive pulley 24B, a second input shaft 25B, a second driven pulley 26B, and a second drive belt 27B. The second drive unit 23B is configured with a motor. The second drive unit 23B is fixed to the main body 10. The second drive unit 23B has a drive shaft 23Ba that protrudes above the main body 10 and extends in the vertical direction. The second drive pulley 24B is fixed to the drive shaft 23Ba. The second drive pulley 24B is formed with the same diameter as the first drive pulley 24A. The second input shaft 25B is provided extending in the vertical direction so as to be parallel to the drive shaft 23Ba and is supported on the main body 10 so as to be rotatable about an axis O1. The second input shaft 25B is cylindrical and disposed outside the first input shaft 25A so as to rotate independently of the first input shaft 25A. The first input shaft 25A and the second input shaft 25B extend downward through the main body 10. The second driven pulley 26B is fixed to a portion of the second input shaft 25B that protrudes upward from the main body 10. The second driven pulley 26B has the same diameter as the first driven pulley 26A and is located below the first driven pulley 26A. The second driven pulley 26B and the second driving pulley 24B are arranged side by side in a direction perpendicular to the second input shaft 25B and the driving shaft 23Ba. The second drive belt 27B is formed in an annular shape and is wound around the second driven pulley 26B and the second driving pulley 24B. Therefore, when the second belt drive mechanism 22B drives the second driving unit 23B, the second driving pulley 24B rotates, and this rotation is transmitted from the second driving pulley 24B to the second driven pulley 26B via the second drive belt 27B, thereby rotating the second input shaft 25B. A pivot shaft 35 is disposed outside the second input shaft 25B.

[0114] The revolving shaft 35 has a cylindrical shape, is disposed outside the second input shaft 25B, extends in the vertical direction, and is supported for rotation about an axis O1. That is, the first input shaft 25A, the second input shaft 25B, and the revolving shaft 35 are disposed coaxially and rotatably along the axis O1. A bearing 43 is provided between the first input shaft 25A and the second input shaft 25B, a bearing 44 is provided between the second input shaft 25B and the revolving shaft 35, and a bearing 45 is provided between the revolving shaft 35 and the main body 10. The revolving shaft 35 has a cylindrical main body 35a and a flange portion 35b integrally provided at the bottom of the main body 35a, and a cover member 35c is provided below the flange portion 35b. A first support member 36A and a second support member 36B are provided on the revolving shaft 35 below the cover member 35c, extending downward on both horizontal sides of the wheel 15. The wheel 15 is integrally provided with an axle 37 extending along an axis O2 perpendicular to the axis O1. One end of the axle 37 along the axis O2 is rotatably supported by the lower part of the first support member 36A, and the other end along the axis O2 is rotatably supported by the lower part of the second support member 36B. The swivel unit 12 is composed of the swivel shaft 35, the first support member 36A, and the second support member 36B. Furthermore, the rotation axis O5 of the wheel 15 along the vertical direction intersecting the axis O2 of the axle 37 is shifted in the horizontal direction perpendicular to the axis O2 of the axle 37 relative to the axis O1 of the swivel shaft 35. Therefore, the drive wheel 103 of this embodiment can input rotational force to the first input shaft 25A and the second input shaft 25B, which are located on the axis O1, which is the swivel axis of the wheel 15.

[0115] A first drive spur gear 38A is fixed to the lower end of the first input shaft 25A, and a second drive spur gear 38B is fixed to the lower end of the second input shaft 25B. The first drive spur gear 38A meshes with a first driven spur gear 39A, and the second drive spur gear 38B meshes with a second driven spur gear 39B. The second drive spur gear 38B and the first drive spur gear 38A are stacked one above the other and rotate around an axis O1. The first driven spur gear 39A is fixed to the upper part of the first output shaft 40A. The upper part of the first output shaft 40A is supported by passing through the flange portion 35b and cover member 35c of the revolving shaft 35, and the lower part is supported by the first support member 36A, so that the first output shaft 40A is rotatable around an axis O3. The second driven spur gear 39B is fixed to the upper part of the second output shaft 40B. The second output shaft 40B is supported at its upper portion by passing through the flange portion 35b and cover member 35c of the revolving shaft 35, and at its lower portion by the second support member 36B, so as to be rotatable about an axis O4. The axes O3 and O4 are parallel to the axis O1. The first driving spur gear 38A, the second driving spur gear 38B, the first driven spur gear 39A, and the second driving spur gear 38B are covered by the flange portion 35b of the revolving shaft 35 and the cover member 35c.

[0116] The first driven spur gear 39A and the first driving spur gear 38A, and the second driving spur gear 38B and the second driven spur gear 39B are arranged so that the axes O1, O3, and O4 form a triangle in a plan view ( FIG. 13 ). The first driven spur gear 39A and the first output shaft 40A, which are centered on the axis O3, and the second driven spur gear 39B and the second output shaft 40B, which are centered on the axis O4, are arranged perpendicular to the wheel 15 on both sides of the axis O2 of the axle 37. Therefore, the rotation axis O5 of the wheel 15, which is perpendicular to the axis O2 of the axle 37, is shifted horizontally from the axis O1 of the turning shaft 35 in a direction perpendicular to the direction of the axis O2 of the axle 37. The first driving spur gear 38A, the second driving spur gear 38B, the first driven spur gear 39A, and the second driven spur gear 39B have the same shape in terms of pitch circle diameter, tooth profile, number of teeth, etc., but they may have different shapes. For example, the first driving spur gear 38A and the second driving spur gear 38B may have different shapes from the first driven spur gear 39A and the second driven spur gear 39B.

[0117] The transmission mechanism 13 has a first spur gear mechanism (first transmission mechanism) 13A and a second spur gear mechanism (second transmission mechanism) 13B. The first spur gear mechanism 13A is made up of a first driving spur gear 38A, a first driven spur gear 39A, and a first output shaft 40A, and the second spur gear mechanism 13B is made up of a second driving spur gear 38B, a second driven spur gear 39B, and a second output shaft 40B.

[0118] A first drive bevel gear 41A is fixed to the lower part of the first output shaft 40A, and a second drive bevel gear 41B is fixed to the lower part of the second output shaft 40B. On the other hand, a first driven bevel gear 42A is fixed to one end of the axle 37 in the direction of the axis O2, and a second driven bevel gear 42B is fixed to the other end in the direction of the axis O2. The first drive bevel gear 41A meshes with the first driven bevel gear 42A. The second drive bevel gear 41B meshes with the second driven bevel gear 42B. The power conversion mechanism 14 includes a first bevel gear mechanism 14A as a first power conversion mechanism and a second bevel gear mechanism 14B as a second power conversion mechanism. The first bevel gear mechanism 14A is composed of the first drive bevel gear 41A and the first driven bevel gear 42A. The second bevel gear mechanism 14B is composed of the second drive bevel gear 41B and the second driven bevel gear 42B.

[0119] The drive mechanism 11 rotates the first input shaft 25A and the second input shaft 25B, thereby rotating and steering the wheels 15. For example, by rotating the first input shaft 25A and rotating the second input shaft 25B in the opposite direction to the first input shaft 25A, and by making the rotational speeds (rotational speeds) of the first input shaft 25A and the second input shaft 25B the same, the wheels 15 can be rotated without being steered. In this case, by making the rotational speeds (rotational speeds) of the first input shaft 25A and the second input shaft 25B different, the wheels 15 can be steered while rotating or stopped.

[0120] Here, we will explain the operation of the drive wheel 103. Figure 14 is a schematic diagram showing the drive force transmission path of the drive wheel 103 of a modified example.

[0121] In the drive wheel 103, when the first input shaft 25A rotates in the first direction A1, the first drive spur gear 38A rotates in the same direction, and the first driven spur gear 39A meshing with the first drive spur gear 38A rotates in the second direction A2. When the first driven spur gear 39A rotates in the second direction A2, the first drive bevel gear 41A, which is integral with the first driven spur gear 39A via the first output shaft 40A, rotates in the same direction. Then, the first driven bevel gear 42A meshing with the first drive bevel gear 41A rotates in the third direction A3, causing the axle 37, which is integral with the first driven bevel gear 42A, to rotate in the same direction. On the other hand, when the second input shaft 25B rotates in the first direction B1, which is the opposite direction to the first direction A1, the second drive spur gear 38B rotates in the same direction, and the second driven spur gear 39B meshing with the second drive spur gear 38B rotates in the second direction B2. When the second driven spur gear 39B rotates in the second direction B2, the second drive bevel gear 41B, which is integral with the second driven spur gear 39B via the second output shaft 40B, rotates in the same direction. This causes the second driven bevel gear 42B, which meshes with the second drive bevel gear 41B, to rotate in the third direction B3, causing the axle 37, which is integral with the second driven bevel gear 42B, to rotate in the same direction. Because the third direction A3 and the third direction B3 are the same rotational direction, if the first input shaft 25A and the second input shaft 25B rotate at the same rotation speed, the wheel 15 rotates without turning.

[0122] At this time, if the rotation speed of the second input shaft 25B is reduced relative to the rotation speed of the first input shaft 25A, the rotation speed input from the second drive bevel gear 41B to the axle 37 via the second driven bevel gear 42B becomes lower than the rotation speed input from the first drive bevel gear 41A to the axle 37 via the first driven bevel gear 42A. This causes the turning shaft 35 to rotate by the rotation speed difference, turning and steering the wheels 15. Furthermore, if the rotation of the second input shaft 25B is stopped, the rotation speed input from the second drive bevel gear 41B to the axle 37 via the second driven bevel gear 42B becomes zero, and the wheels 15 turn and steer without rotating.

[0123] That is, when the gear ratios of the first drive spur gear 38A, the second drive spur gear 38B, the first driven spur gear 39A, and the second driven spur gear 39B are the same, and the gear ratios of the first drive bevel gear 41A, the second drive bevel gear 41B, the first driven bevel gear 42A, and the second driven bevel gear 42B are the same, then, if the rotation speed of the first input shaft 25A is NA, the rotation speed of the second input shaft 25B is NB, the rotation speed of the pivot shaft 35 is NS, and the rotation speed of the wheel 15 is NW, the rotation speed NS of the pivot shaft 35 and the rotation speed NW of the wheel 15 are related by the following mathematical formula. NW=(1 / 2)NA-(1 / 2)NB NS=-(1 / 2)NA-(1 / 2)NB NA=NW-NS NB=-NW-NS

[0124] As shown in FIG. 6 , the drive wheel 103 of this embodiment includes a turning position detector 50. The turning position detector 50 is provided on the upper surface of the main body 10. Although not shown in the figure, the turning position detector 50 includes, for example, a first spur gear that rotates around the axis O1 together with the turning shaft 35, a second spur gear that meshes with the first spur gear and rotates around an axis parallel to the axis O1, and a detector that detects the rotational position of the second spur gear. Therefore, the first spur gear rotates together with the turning shaft 35, and the detector detects the rotational position of the first spur gear as the rotational position of the second spur gear, thereby detecting the rotational position of the turning shaft 35, i.e., the rotational position of the turning unit 12 relative to the main body 10. The detection signal from the detector is input to the control device 107A of the driving assistance device 100A. As a result, the control device 107A can control the turning of the drive wheel 103.

[0125] The driving wheel 103 of the embodiment further includes a torque measuring unit 28 .

[0126] 6 and 9, the torque measurement unit 28 has a first torque measurement unit 28A and a second torque measurement unit 28B. The first torque measurement unit 28A is provided in the first belt drive mechanism 22A and measures the torque applied to the first belt drive mechanism 22A. The second torque measurement unit 28B is provided in the second belt drive mechanism 22B and measures the torque applied to the second belt drive mechanism 22B. Here, the first torque measurement unit 28A and the second torque measurement unit 28B have the same configuration, so only the first torque measurement unit 28A will be described and a detailed description of the second torque measurement unit 28B will be omitted.

[0127] The first torque measurement unit 28A is provided in the first belt drive mechanism 22A with respect to the first drive belt 27A between the first drive pulley 24A and the first driven pulley 26A, and includes first pressure rollers 29Aa and 29Ab, first strain gauges 30Aa and 30Ab, and first tension measurement units 31Aa and 31Ab. The first pressure rollers 29Aa and 29Ab contact one side and the other side of the first drive belt 27A between the first drive pulley 24A and the first driven pulley 26A. The one side and the other side of the first drive belt 27A refer to the portion of the first drive belt 27A that moves away from the first drive pulley 24A and the portion of the first drive belt 27A that moves toward the first drive pulley 24A when the first drive belt 27A moves in accordance with the rotation of the first drive pulley 24A, and can also be said to be the upstream side and the downstream side of the first drive belt 27A. The first strain gauges 30Aa and 30Ab support the first pressure rollers 29Aa and 29Ab, respectively, and receive strain from the movement of the first pressure rollers 29Aa and 29Ab that accompanies changes in the tension of the first drive belt 27A. The first tension measuring units 31Aa and 31Ab are connected to the first strain gauges 30Aa and 30Ab, respectively, and read the strain of the first strain gauges 30Aa and 30Ab as voltage values. This voltage value is calculated by the control device 107A as the torque applied to one side and the other side of the first drive belt 27A.

[0128] The second torque measurement unit 28B is provided for the second drive belt 27B between the second drive pulley 24B and the second driven pulley 26B in the second belt drive mechanism 22B, and includes second pressure rollers 29Ba, 29Bb similar to the first pressure rollers 29Aa, 29Ab, second strain gauges 30Ba, 30Bb similar to the first strain gauges 30Aa, 30Ab, and second tension measurement units 31Ba, 31Bb similar to the first tension measurement units 31Aa, 31Ab.

[0129] 15 is a block diagram showing an example configuration of a modified driving wheel 103. Control device 107A acquires the torque (voltage value) measured by first torque measurement unit 28A and the torque (voltage value) measured by second torque measurement unit 28B. Third external force detection unit 105A detects the torque (voltage value) of driving wheel 103 measured by torque measurement units 28 (28A, 28B) described below as a third external force acting on driving wheel 103.

[0130] The control device 107A calculates a second external force in the horizontal direction (XY direction) on the vehicle body 101 based on the third external force acting on each of the four drive wheels 103 obtained from the third external force detection unit 105A. The control device 107A controls the first drive unit 23A and the second drive unit 23B based on the detection results obtained from the first external force detection unit 104 and the third external force detection unit 105A.

[0131] As described above, in the modified driving assistance device 100A, in any of the driving assistance devices 100 of the first, second, and third embodiments, instead of the third external force detection unit 105A detecting the second horizontal external force acting on the support unit 102, the third external force detection unit 105A detects the torque measured at the drive wheel 103 as the third external force acting on the drive wheel 103, and the control unit 107A calculates the horizontal external force acting on the body unit 101 as the second external force based on the third external force.

[0132] This makes it possible to obtain the second external force by utilizing a torque detection mechanism that is provided in advance near drive wheel 103 or a drive unit that drives drive wheel 103. With this configuration, since the detection point is near drive wheel 103, it is not possible to accurately measure the force that is lost when force is transmitted from support unit 102. However, in the present invention, regardless of the magnitude of the second external force, the vehicle is driven by drive control using an arbitrary drive force or speed control using an arbitrary speed, so that it is possible to suppress the influence of inaccuracies in the detected value due to losses, and sufficient driving assistance can be achieved.

[0133] The present invention is not limited to the above-described embodiment. In other words, various modifications can be made without departing from the gist of the present invention. For example, the support portion 102 of the travel assistance device 100, 100A is not limited to a device that directly supports the load L, but may be configured to be connected to a device that supports the load L and receives the load. [Explanation of symbols]

[0134] 100, 100A Driving Assist Device 101 Body 102 Support part 103 Drive Wheel 104 First external force detection unit 105 Second external force detection unit 105A Third external force detection unit 106 Power supply section 107, 107A control device L Object to be transported 10 Main Unit 11 Drive mechanism 12 Swivel section 13 Transmission Mechanism 13A First spur gear mechanism 13B Second spur gear mechanism 14 Power conversion mechanism 15 wheels 22A First belt drive mechanism 22B Second belt drive mechanism 28 Torque measurement unit 28A First torque measurement unit 28B Second torque measurement unit 29Aa, 29Ab First pressure roller 29Ba, 29Bb Second pressure roller 30Aa, 30Ab, 30Ba, 30Bb gauge 31Aa, 31Ab First tension measurement section 31Ba, 31Bb Second tension measurement section 35 Swivel axis 37 axles 50 Turning position detection unit

Claims

1. drive wheels attached to the vehicle body to drive the vehicle body; a support portion on the upper surface side of the vehicle body portion for carrying an object to be transported; a first external force detection unit that detects the magnitude of a first external force applied to the support unit in a vertical direction; a second external force detection unit that detects the magnitude and direction of a second external force applied to the support unit in a horizontal direction; a control device; The control device driving the drive wheels with a drive force set based on the first external force so that the vehicle body moves in the direction of the second external force; Driving assistance device.

2. The control device When it is determined that the magnitude of the second external force is greater than a predetermined threshold, the driving wheels are driven by the driving force so that the vehicle body moves in the direction of the second external force; When it is determined that the magnitude of the second external force is equal to or less than a predetermined threshold, the driving state of the driving wheels is maintained. The driving assistance device according to claim 1 .

3. drive wheels attached to the vehicle body to drive the vehicle body; a support portion on the upper surface side of the vehicle body portion for carrying an object to be transported; a first external force detection unit that detects the magnitude of a first external force applied to the support unit in a vertical direction; a second external force detection unit that detects the magnitude and direction of a second external force applied to the support unit in a horizontal direction; a control device; The control device driving the drive wheels so that the vehicle body moves in the direction of the second external force at a predetermined constant speed; Driving assistance device.

4. The control device After accelerating to the speed in the direction of the second external force at an acceleration set based on the first external force, the drive wheels are driven so that the vehicle body moves at the speed. The driving assistance device according to claim 3 .

5. The control device When it is determined that the magnitude of the second external force is greater than a predetermined threshold, the drive wheels are driven so that the vehicle body moves in the direction of the second external force at the speed; When it is determined that the magnitude of the second external force is equal to or less than a predetermined threshold, the driving state of the driving wheels is maintained. The driving assistance device according to claim 3 .

6. The first external force detection unit provided between the support portion and the vehicle body portion, a vertical force applied from the support portion to the vehicle body portion is detected as the first external force; The driving assistance device according to any one of claims 1 to 5.

7. The second external force detection unit is provided between the support portion and the vehicle body portion, a horizontal force applied from the support portion to the vehicle body portion is detected as the second external force; The driving assistance device according to any one of claims 1 to 5.

8. The second external force detection unit is Instead of detecting the second horizontal external force acting on the support, detecting a torque measured at the drive wheel as a third external force acting on the drive wheel; The control device a horizontal external force acting on the vehicle body section is calculated as the second external force based on the third external force; The driving assistance device according to any one of claims 1 to 5.

9. drive wheels attached to the vehicle body to drive the vehicle body; a support portion on the upper surface side of the vehicle body portion for carrying an object to be transported; a first external force detection unit that detects the magnitude of a first external force applied to the support unit in a vertical direction; a second external force detection unit that detects the magnitude and direction of a second external force applied to the support unit in a horizontal direction; A driving assistance method using a driving assistance device comprising: Detecting the magnitude of the first external force; setting a driving force for driving the drive wheels based on the first external force; detecting the magnitude and direction of the second external force; driving the drive wheels with the set driving force so that the vehicle body moves in the direction of the second external force; Including, Driving assistance method.

10. determining whether to change the drive state of the drive wheels based on the magnitude of the second external force; When it is determined that the magnitude of the second external force is greater than a predetermined threshold, driving the drive wheels so that the vehicle body moves in the direction of the second external force; maintaining the drive state of the drive wheels when it is determined that the magnitude of the second external force is equal to or less than a predetermined threshold; Further comprising: The driving assistance method according to claim 9.

11. drive wheels attached to the vehicle body to drive the vehicle body; a support portion on the upper surface side of the vehicle body portion for carrying an object to be transported; a first external force detection unit that detects the magnitude of a first external force applied to the support unit in a vertical direction; a second external force detection unit that detects the magnitude and direction of a second external force applied to the support unit in a horizontal direction; A driving assistance method using a driving assistance device comprising: detecting the magnitude and direction of the second external force; Driving the drive wheels so that the vehicle body moves in the direction of the second external force at a predetermined constant speed; Including, Driving assistance method.

12. Detecting the magnitude of the first external force; setting an acceleration to accelerate to the speed based on the first external force; After accelerating to the speed in the direction of the second external force at the acceleration, driving the drive wheels so that the vehicle body moves at the speed; Further comprising: The driving assistance method according to claim 11.

13. determining whether to change the drive state of the drive wheels based on the magnitude of the second external force; When it is determined that the magnitude of the second external force is greater than a predetermined threshold, driving the drive wheels so that the vehicle body moves in the direction of the second external force at the speed; maintaining the drive state of the drive wheels when it is determined that the magnitude of the second external force is equal to or less than a predetermined threshold; Including, The driving assistance method according to claim 11.

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