Carrying vehicle

Abstract

Provided is a technology capable of suppressing a user from swinging when a transport vehicle performs a turning operation. A transport vehicle disclosed in the present specification may comprise: a vehicle body; wheels which are supported by the vehicle body and are in contact with the ground; a prime mover that drives the wheels; a handle held by a user walking behind the vehicle body; and a control unit that controls the operation of the prime mover. Alternatively, when the transport vehicle performs a turning operation, the control means sets the target vehicle body speed during the turning operation when the turning radius of the vehicle body is small to be lower than the target vehicle body speed when the turning radius of the vehicle body is large.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a transport vehicle. Background Art

[0002] Japanese Patent Application Laid-Open No. 2000-78708 discloses a transport vehicle, which includes a vehicle body, wheels supported by the vehicle body and in contact with the ground, a prime mover that drives the wheels, a handle that is held by a user standing behind the vehicle body, and a control unit that controls the movement of the prime mover. Summary of the invention

[0003] Problem that the invention aims to solve

[0004] When a transport truck performs a turning maneuver, a user walking behind the vehicle body while holding a handle moves faster than the vehicle body. In particular, the smaller the turning radius of the vehicle body, the faster the user walking behind the vehicle body while holding a handle moves than the vehicle body. Therefore, there is a case where the user sways when the transport truck performs a turning maneuver. This specification provides a technology that can suppress the situation where the user sways when the transport truck performs a turning maneuver.

[0005] Solutions for solving problems

[0006] The transport vehicle disclosed in this specification may also include: a vehicle body; wheels supported by the vehicle body and in contact with the ground; a prime mover that drives the wheels; a handle that is held by a user walking behind the vehicle body; and a control unit that controls the operation of the prime mover. Alternatively, when the transport vehicle performs a turning action, the control unit sets a target vehicle body speed when the turning radius of the vehicle body is small to be smaller than the target vehicle body speed when the turning radius of the vehicle body is large.

[0007] According to the above structure, when the transport truck performs a turning action, the smaller the turning radius of the vehicle body is, the lower the speed of the vehicle body during the turning action can be. This can suppress the increase in the speed of the user when the transport truck performs a turning action. It can also suppress the user from swaying when the transport truck performs a turning action. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a perspective view of the transport vehicle 2 according to the embodiment.

[0009] Figure 2 It is a block diagram of the transport vehicle 2 according to the embodiment.

[0010] Figure 3 This is a flowchart of a turning operation process performed by the control unit 52 of the transport vehicle 2 of the embodiment.

[0011] Figure 4 Schematically shows the relationship between the vehicle body speed Vb and the user speed Vu when the transport vehicle 2 of the embodiment performs a turning maneuver.

[0012] Figure 5 : is a graph showing an example of the relationship among the curvature of the turning motion of the transport vehicle 2, the vehicle body speed, and the user speed.

[0013] Figure 6 : is a graph showing another example of the relationship among the curvature of the turning motion of the transport vehicle 2, the vehicle body speed, and the user speed.

[0014] Figure 7 : This is a graph showing an example of the relationship between the handle angle, the target vehicle body speed, and their approximate function in the transport vehicle 2 of the embodiment. DETAILED DESCRIPTION

[0015] Representative and non-limiting specific examples of the present invention are described in detail below with reference to the accompanying drawings. This detailed description is intended to simply show the details of the preferred examples for implementing the present invention to those skilled in the art, and is not intended to limit the scope of the present invention. In addition, in order to provide a further improved transport vehicle and its manufacturing method and use method, the additional features and technical solutions disclosed below can be used separately or together with other features and technical solutions.

[0016] In addition, the combination of features and processes disclosed in the following detailed description is not essential in the broadest sense when implementing the present invention, and is only recorded for the purpose of specifically illustrating the representative specific examples of the present invention. Furthermore, when providing additional and useful embodiments of the present invention, the various features of the representative specific examples described above and below and the various features described in the independent claims and dependent claims do not necessarily have to be combined as in the specific examples described herein or in the order in which they are listed.

[0017] All features described in this specification and / or claims are intended to be disclosed separately and independently of the structures of the features described in the embodiments and / or claims as limitations on the disclosure and specific matters claimed in the original application. Furthermore, all numerical ranges and records related to organizations or groups are intended to disclose the above-mentioned intermediate structures as limitations on the disclosure and specific matters claimed in the original application.

[0018] In one or more embodiments, the transport vehicle may further include a steering mechanism for steering at least one of the wheels as a steering wheel.

[0019] In a transport vehicle with a steering mechanism, a turning action is sometimes performed without sufficiently reducing the speed of the vehicle body, so the user is easily swayed when the transport vehicle performs a turning action. According to the above structure, it is possible to suppress the user from swaying when the transport vehicle with a steering mechanism performs a turning action.

[0020] In one or more embodiments, the handle may be supported on the vehicle body so as to be rotatable around a rotation axis, or may be configured to be rotatably operated by the user. Alternatively, the transport vehicle may further include a handle angle sensor, which detects a rotation angle of the handle around the rotation axis as a handle angle. Alternatively, the control unit may set a target steering angle of the steering wheel during the turning action based on the handle angle. Alternatively, the control unit may set a target vehicle body speed during the turning action based on the handle angle.

[0021] When the transport vehicle performs a turning action according to the user's rotation operation of the handle, the larger the handle angle, the smaller the turning radius of the vehicle body, and the smaller the handle angle, the larger the turning radius of the vehicle body. According to the above structure, the target vehicle body speed during the turning action when the turning radius of the vehicle body is small can be set to be smaller than the target vehicle body speed when the turning radius of the vehicle body is large by using a simple structure.

[0022] In one or more embodiments, the control unit may calculate the target vehicle body speed as a linear function of the handle angle.

[0023] According to the above configuration, the processing load of the control unit can be reduced.

[0024] In one or more embodiments, the prime mover may include a plurality of motors provided corresponding to the wheels, respectively.

[0025] According to the above configuration, it is possible to easily adjust the speed of the vehicle body when the transport vehicle performs a turning action.

[0026] (Example)

[0027] Figure 1 The transport vehicle 2 shown in the figure includes a vehicle body 4, a shelf 6, a handle 8, a right front wheel 10, a left front wheel 12, a right rear wheel 14, and a left rear wheel 16. The shelf 6, the handle 8, the right front wheel 10, the left front wheel 12, the right rear wheel 14, and the left rear wheel 16 are all supported by the vehicle body 4. The transport vehicle 2 transports the goods loaded on the shelf 6. The transport vehicle 2 includes a wireless interface (I / F) 18 (see Figure 2). The transporter 2 can operate in any of the manual mode, the automatic mode, or the parking mode. In the manual mode, the transporter 2 moves forward or backward according to the operation performed by the user while the user standing at the rear of the vehicle body 4 holds the handle 8 with both hands. In the automatic mode, the transporter 2 performs a tracking operation in which it moves following a beacon (not shown) carried by the user standing in front of the vehicle body 4, or a remote control operation in which it moves according to instructions from a remote controller (not shown) operated by the user. In this case, the transporter 2 uses the wireless I / F 18 to receive radio waves from the beacon and the remote controller. In the parking mode, the transporter 2 neither accepts instructions from the handle 8 nor from the beacon and the remote controller, but continues to stay where it is.

[0028] The transport vehicle 2 includes a battery mounting portion 20 provided on the vehicle body 4. The battery pack 22 (see Figure 2 ) can be attached and detached from the battery mounting portion 20. The battery pack 22 includes secondary battery cells (not shown) such as lithium-ion battery cells, and can be recharged using a charger (not shown). The transport vehicle 2 is operated by the power supplied from the battery pack 22 mounted on the battery mounting portion 20.

[0029] like Figure 2 As shown, the transport vehicle 2 includes a right front wheel motor 24 for driving the right front wheel 10, a left front wheel motor 26 for driving the left front wheel 12, a right rear wheel motor 28 for driving the right rear wheel 14, and a left rear wheel motor 30 for driving the left rear wheel 16. The right front wheel motor 24, the left front wheel motor 26, the right rear wheel motor 28, and the left rear wheel motor 30 are, for example, brushless motors. The right front wheel motor 24, the left front wheel motor 26, the right rear wheel motor 28, and the left rear wheel motor 30 are supported by the vehicle body 4.

[0030] like Figure 1 As shown in FIG. 1 , the handle 8 can rotate relative to the vehicle body 4 about a rotation axis extending in the vertical direction. The user can rotate the handle 8 while holding the handle 8 with both hands. Figure 2 As shown, the transport vehicle 2 includes: a handle angle sensor 32 that detects the rotation angle of the handle 8 as a handle angle; a steering mechanism 34 that steers the right front wheel 10 and the left front wheel 12 as steering wheels; and a steering motor 36 that drives the steering mechanism 34. The steering motor 36 is, for example, a brushless motor. The handle angle sensor 32, the steering mechanism 34, and the steering motor 36 are supported by the vehicle body 4.

[0031] like Figure 1 As shown, a switch box 38 is provided on the handle 8. Figure 2As shown, the switch box 38 is provided with a main power switch 40, a mode switch 42, a trigger switch 44, a travel direction switch 46, and a speed switch 48. The main power switch 40 can switch the main power of the transport vehicle 2 on / off. The mode switch 42 can switch the operation mode of the transport vehicle 2 between the manual mode, the automatic mode, and the parking mode. The trigger switch 44 can switch the forward and reverse on / off of the transport vehicle 2 in the manual mode and adjust the travel speed of the transport vehicle 2. The travel direction switch 46 can switch the travel direction of the transport vehicle 2 in the manual mode. The speed switch 48 can switch the travel speed of the transport vehicle 2 in the manual mode. The user can operate the main power switch 40, the mode switch 42, the trigger switch 44, the travel direction switch 46, and the speed switch 48 while holding the handle 8 with both hands.

[0032] The transport vehicle 2 includes a control power circuit 50 and a control unit 52. The control power circuit 50 allows the power supply from the battery pack 22 when the main power switch 40 is turned on, and prohibits the power supply from the battery pack 22 when the main power switch 40 is turned off. The control unit 52 controls the operation of the transport vehicle 2. The control unit 52 controls the operation of the right front wheel motor 24, the left front wheel motor 26, the right rear wheel motor 28, the left rear wheel motor 30, and the steering motor 36 through the motor drivers 54, 56, 58, 60, and 62. In addition, the motor drivers 54, 56, 58, and 60 are connected to brake circuits 64, 66, 68, and 70 corresponding to the right front wheel motor 24, the left front wheel motor 26, the right rear wheel motor 28, and the left rear wheel motor 30. The control unit 52 allows a large current to flow through the brake circuits 64, 66, 68, 70 during the rotation of the right front wheel motor 24, the left front wheel motor 26, the right rear wheel motor 28, and the left rear wheel motor 30, thereby being able to apply a large braking force to the right front wheel motor 24, the left front wheel motor 26, the right rear wheel motor 28, and the left rear wheel motor 30. The control power supply circuit 50, the control unit 52, the motor drivers 54, 56, 58, 60, 62, and the brake circuits 64, 66, 68, 70 are supported by the vehicle body 4.

[0033] (Turning action processing)

[0034] When the manual mode is selected with the main power of the transport vehicle 2 turned on, the control unit 52 executes Figure 3 Turning maneuver handling shown.

[0035] In S2 , the control unit 52 acquires the handle angle of the handle 8 using the handle angle sensor 32 .

[0036] In S4, the control unit 52 determines the target steering angles of the right front wheel 10 and the left front wheel 12 based on the handle angle acquired in S2.

[0037] In S6, the control unit 52 determines a target vehicle body speed in the turning maneuver based on the handle angle acquired in S2.

[0038] In S8, the control unit 52 controls the steering motor 36 based on the target steering angle determined in S4 to drive the steering mechanism 34, and controls the right front wheel motor 24, the left front wheel motor 26, the right rear wheel motor 28, and the left rear wheel motor 30 based on the target vehicle body speed determined in S6 to drive the right front wheel 10, the left front wheel 12, the right rear wheel 14, and the left rear wheel 16. Thus, the turning action of the transport vehicle 2 is achieved in such a way that the steering angles of the right front wheel 10 and the left front wheel 12 become the target steering angles determined in S4, and the speed of the vehicle body 4 becomes the target vehicle body speed determined in S6. After S8, the process returns to S2.

[0039] (Vehicle speed control during cornering)

[0040] Figure 4 The figure shows the relationship between the speed of the vehicle body 4, that is, the vehicle body speed Vb, and the speed of the user U, that is, the user speed Vu, when the transport vehicle 2 performs a turning action. Figure 4 In the example shown, the user U turns the handle 8 in the clockwise direction when viewed from above, thereby turning the transport vehicle 2 clockwise relative to the turning center Cr. In this case, the turning radius Ru of the user U is larger than the turning radius Rb of the vehicle body 4, so the user speed Vu during the turning action is larger than the vehicle body speed Vb during the turning action. Specifically, the relationship Vu = Vb × Ru / Rb holds. In addition, if the user U turns clockwise, the vehicle body speed Vb will be greater than the vehicle body speed Vb. Figure 4 As clearly shown, the smaller the turning radius Rb of the vehicle body 4 is, the larger the value of Ru / Rb is, and the larger the turning radius Rb of the vehicle body 4 is, the smaller the value of Ru / Rb is, and approaches 1.

[0041] Figure 5 An example of the relationship between the curvature of the turning motion of the transport vehicle 2 (the inverse of the turning radius Rb of the vehicle body 4), the vehicle body speed Vb, and the user speed Vu is shown. Figure 5 In the example shown, the vehicle body speed Vb is made constant regardless of the curvature of the turning action. In this case, if the curvature of the turning action becomes smaller (that is, if the turning radius Rb becomes larger), the user speed Vu becomes a value close to the vehicle body speed Vb, but if the curvature of the turning action becomes larger (that is, if the turning radius Rb becomes smaller), the user speed Vu becomes a value larger than the vehicle body speed Vb. Therefore, when the transport vehicle 2 performs a turning action with a large curvature (that is, with a small turning radius Rb), the user walking behind the vehicle body 4 while holding the handle 8 will sway.

[0042] Figure 6FIG. 2 shows another example of the relationship between the curvature of the turning motion of the transport vehicle 2, the vehicle body speed Vb, and the user speed Vu. Figure 6 In the example shown, the greater the curvature of the turning action (i.e., the smaller the turning radius Rb), the smaller the vehicle body speed Vb. In this case, the user speed Vu can be made constant regardless of the curvature of the turning action. Therefore, even if the transport vehicle 2 performs a turning action with a large curvature (i.e., with a small turning radius Rb), the user walking behind the vehicle body 4 while holding the handle 8 will not be swayed.

[0043] Furthermore, in the transport vehicle 2 of the present embodiment, as the handle angle of the handle 8 increases, the steering angle of the steering mechanism 34 also increases, and the curvature of the turning action of the transport vehicle 2 also increases. Conversely, as the handle angle of the handle 8 decreases, the steering angle of the steering mechanism 34 also decreases, and the curvature of the turning action of the transport vehicle 2 also decreases. Therefore, even if the handle angle of the handle 8 is increased, the steering angle of the steering mechanism 34 also decreases, and the curvature of the turning action of the transport vehicle 2 also decreases. Figure 5 and Figure 6 The horizontal axis of the graph of is replaced by the handle angle or the steering angle, and the same relationship also holds true between the vehicle body speed Vb and the user speed Vu.

[0044] like Figure 7 As shown, the control unit 52 of this embodiment calculates the target vehicle body speed Vb as a function of the handle angle in order to make the user speed Vu constant during the turning action (see Figure 3 S6). Figure 7 In FIG. 1 , the relationship between the handle angle and the target vehicle speed Vb is illustrated for the cases where the travel speed of the transport vehicle 2 is low speed, medium speed, and high speed, respectively. However, the same relationship is established for any speed corresponding to the operation amount of the trigger switch 44. Figure 7 In the example shown, the smaller the handle angle (i.e., the smaller the steering angle / the smaller the curvature of the turning action / the larger the turning radius of the vehicle body 4), the larger the target vehicle body speed Vb during the turning action is set. Conversely, the larger the handle angle (i.e., the larger the steering angle / the larger the curvature of the turning action / the smaller the turning radius of the vehicle body 4), the smaller the target vehicle body speed Vb during the turning action is set. By providing the target vehicle body speed Vb in this way, it is possible to suppress the swaying of the user who is walking behind the vehicle body 4 while holding the handle 8 during the turning action of the transport vehicle 2. In addition, Figure 3 In S6, the control unit 52 may calculate the target vehicle speed Vb as a function of the handle angle instead of calculating the target vehicle speed Vb as a function of the steering angle, or may calculate the target vehicle speed Vb as a function of the curvature of the turning action, or may calculate the target vehicle speed Vb as a function of the turning radius of the vehicle body 4.

[0045] In addition, if Figure 7As shown, the target vehicle body speed Vb for making the user speed Vu constant can be approximately calculated using a linear function of the handle angle (or a linear function of the steering angle or a linear function of the curvature of the turning action). Therefore, in the transport vehicle 2 of the present embodiment, the control unit 52 calculates the target vehicle body speed Vb using a linear function of the handle angle. For example, the target vehicle body speed Vb is calculated by Vb=Vb0×(1-a×θ / θmax). Here, Vb0 is the vehicle body speed when traveling straight, θ is the handle angle, θ is the maximum handle angle (constant), and a is a positive constant. By setting it as such a structure, the processing load of the control unit 52 can be reduced.

[0046] In the above description, the control of the vehicle body speed during the turning operation performed by the control unit 52 when the transport vehicle 2 is moving forward is described. However, the control unit 52 may also perform the same control when the transport vehicle 2 is moving backward.

[0047] (Variation Example)

[0048] In the above-mentioned embodiment, the right front wheel motor 24, the left front wheel motor 26, the right rear wheel motor 28 and the left rear wheel motor 30 may be in-wheel motors (not shown) installed in the right front wheel 10, the left front wheel 12, the right rear wheel 14 and the left rear wheel 16.

[0049] In the above-mentioned embodiment, the right front wheel motor 24, the left front wheel motor 26, the right rear wheel motor 28, the left rear wheel motor 30 and the steering motor 36 may also be brushed DC motors, AC motors or other types of motors.

[0050] In the above-described embodiment, a configuration may be adopted in which the steering mechanism 34 is driven by another type of actuator instead of the steering motor 36 .

[0051] In the above-mentioned embodiment, the following structure may be adopted: instead of the right front wheel motor 24, the left front wheel motor 26, the right rear wheel motor 28 and the left rear wheel motor 30, an internal combustion engine may be used to drive the right front wheel 10, the left front wheel 12, the right rear wheel 14 and / or the left rear wheel 16.

[0052] In the above-described embodiment, a configuration may be adopted in which electric power is supplied to the transport vehicle 2 from a power source disposed outside the transport vehicle 2 via a power line instead of the battery pack 22 .

[0053] As described above, in one or more embodiments, the transport vehicle 2 includes the vehicle body 4, the right front wheel 10, the left front wheel 12, the right rear wheel 14, and the left rear wheel 16 (examples of wheels) supported by the vehicle body 4 and in contact with the ground, the right front wheel motor 24, the left front wheel motor 26, the right rear wheel motor 28, and the left rear wheel motor 30 (examples of prime movers) that drive the right front wheel 10, the left front wheel 12, the right rear wheel 14, and the left rear wheel 16, the handle 8 held by the user walking behind the vehicle body 4, and the control unit 52 that controls the operation of the right front wheel motor 24, the left front wheel motor 26, the right rear wheel motor 28, and the left rear wheel motor 30. When the transport vehicle 2 performs a turning action, the control unit 52 sets a target vehicle body speed when the turning radius of the vehicle body 4 is small to be smaller than the target vehicle body speed when the turning radius of the vehicle body 4 is large.

[0054] According to the above structure, when the transport vehicle 2 performs a turning maneuver, the smaller the turning radius of the vehicle body 4 is, the lower the speed of the vehicle body 4 during the turning maneuver can be. This can suppress the increase in the speed of the user when the transport vehicle 2 performs a turning maneuver. It can also suppress the user from swaying when the transport vehicle 2 performs a turning maneuver.

[0055] In one or more embodiments, the transport vehicle 2 further includes a steering mechanism 34 for steering the right front wheel 10 and the left front wheel 12 as steerable wheels.

[0056] In the transport vehicle 2 having the steering mechanism 34, the turning action is sometimes performed without sufficiently reducing the speed of the vehicle body 4, so the user is easily swayed when the transport vehicle 2 performs the turning action. According to the above-mentioned structure, it is possible to suppress the user from swaying when the transport vehicle 2 having the steering mechanism 34 performs the turning action.

[0057] In one or more embodiments, the handle 8 is supported on the vehicle body 4 so as to be rotatable around the rotation axis, and is configured to be rotated by the user. The transport vehicle 2 further includes a handle angle sensor 32 that detects the rotation angle of the handle 8 around the rotation axis as the handle angle. The control unit 52 sets the target steering angle of the steering wheel during the turning action based on the handle angle. The control unit 52 sets the target vehicle body speed during the turning action based on the handle angle.

[0058] When the transport vehicle 2 performs a turning action according to the user's rotation operation of the handle 8, the larger the handle angle, the smaller the turning radius of the vehicle body 4, and the smaller the handle angle, the larger the turning radius of the vehicle body 4. According to the above structure, the target vehicle body speed during the turning action when the turning radius of the vehicle body 4 is small can be set to be smaller than the target vehicle body speed when the turning radius of the vehicle body 4 is large by a simple structure.

[0059] In one or more embodiments, the control unit 52 calculates the target vehicle body speed as a linear function of the handle angle.

[0060] According to the above-mentioned configuration, the processing load of the control unit 52 can be reduced.

[0061] In one or more embodiments, the right front wheel motor 24, the left front wheel motor 26, the right rear wheel motor 28, and the left rear wheel motor 30 are respectively arranged corresponding to the right front wheel 10, the left front wheel 12, the right rear wheel 14, and the left rear wheel 16.

[0062] According to the above-described configuration, it is possible to easily adjust the speed of the vehicle body 4 when the transport vehicle 2 performs a turning operation.

Claims

1. A transport vehicle, wherein: The transporter has: Car body; wheels, which are supported by the vehicle body and in contact with the ground; a prime mover that drives the wheels; a handle to be held by a user walking behind the vehicle body; as well as a control unit that controls the action of the prime mover, When the transport vehicle performs a turning action, the control unit sets a target vehicle body speed during the turning action when the turning radius of the vehicle body is small to be smaller than the target vehicle body speed when the turning radius of the vehicle body is large.

2. The transport vehicle according to claim 1, wherein: The transport vehicle further includes a steering mechanism for steering at least one of the wheels as a steering wheel.

3. The transport vehicle according to claim 2, wherein: The handle is supported on the vehicle body so as to be rotatable about a rotation axis and is configured to be rotated by the user. The transport vehicle further includes a handle angle sensor for detecting a rotation angle of the handle around the rotation axis as a handle angle. The control unit sets a target steering angle of the steering wheel during the turning action based on the handle angle. The control unit sets the target vehicle body speed during the turning maneuver based on the handle angle.

4. The transport vehicle according to claim 3, wherein: The control unit calculates the target vehicle body speed as a linear function of the handle angle.

5. The transport vehicle according to any one of claims 1 to 4, wherein: The prime mover includes a plurality of motors provided corresponding to the wheels, respectively.

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