DARE

Abstract

A cart may contain: a vehicle body; wheels supported or carried by the vehicle body and configured to be in contact with a ground; a primary drive or drive unit configured to power the wheels; a handle configured to be gripped by a user walking behind the vehicle body; and a control unit configured to control or regulate the operation of the drive unit. When the cart is performing a turning maneuver, the control unit may be configured to set a slower target vehicle speed for a turning maneuver with a small turning radius, compared to a target vehicle speed for a turning maneuver with a large turning radius.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a car. STATE OF THE ART

[0002] Japanese Patent Application Publication No. 2000-78708 describes a cart. The cart includes a vehicle body, wheels supported by the vehicle body and configured to be in contact with a ground, a prime mover configured to drive the wheels, a handle configured to be grasped by a user walking behind the vehicle body, and a control unit configured to control operation of the prime mover. SUMMARY

[0003] When a cart performs a turning motion, a user walking behind the cart body and grasping the handle must move faster than the cart body. Particularly, with a smaller turning radius of the cart body, the user walking behind the cart body and grasping the handle must move even faster than the cart body. Therefore, the user may be pulled or swayed by the cart's turning motion. The technology disclosed herein provides a technology that prevents a user from being pulled or swayed when a cart performs a turning motion.

[0004] A cart disclosed herein may include: a vehicle body; wheels supported by the vehicle body and configured to be in contact with a ground; a prime mover configured to drive the wheels; a handle configured to be grasped by a user walking behind the vehicle body; and a control unit configured to control operation of the drive unit. When the cart performs a turning movement, the control unit may be configured to set a slower target vehicle speed for a turning movement in which a turning radius of the vehicle body is small, compared to a target vehicle speed for a turning movement in which a turning radius of the vehicle body is large.

[0005] The above configuration allows the vehicle body speed to be slower for a turning movement where the turning radius of the vehicle body is smaller. This prevents the user's speed from increasing when the cart makes a turning movement. Thus, it is possible to prevent the user from being dragged or swayed when the cart makes a turning movement. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a perspective view of a carriage 2 according to an embodiment. Fig. 2 shows a block diagram of the carriage 2 according to the embodiment. Fig. 3 shows a flowchart of a turning movement process by a control unit 52 of the carriage 2 according to the embodiment. Fig. 4 schematically shows a relationship between vehicle speed Vb and user speed Vu when the car 2 performs a turning movement. Fig. 5 shows a graph illustrating an exemplary relationship between turning curvature and vehicle speed of the car 2 and user speed. Fig. 6 shows a graph illustrating another exemplary relationship between turning curvature and vehicle speed of the car 2 and user speed. Fig. 7 is a graph illustrating an exemplary relationship between a grip angle, a target vehicle speed, and their approximate function in the car 2 according to the embodiment. DESCRIPTION

[0006] Representative, non-limiting examples of the present disclosure will now be described in more detail with reference to the accompanying drawings. This detailed description is merely intended to provide a person skilled in the art with further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the present disclosure. Furthermore, each of the additional features and teachings disclosed below may be used separately or in conjunction with other features and teachings to provide improved carts and methods of using and manufacturing them.

[0007] Furthermore, combinations of features and steps disclosed in the following detailed description may not be necessary to practice the present disclosure in its broadest sense, and are instead taught merely to particularly describe representative examples of the present disclosure. Furthermore, various features of the representative examples described above and below, as well as the various independent and dependent claims, may be combined in ways that are not specifically and explicitly enumerated to provide additional useful embodiments of the present teachings.

[0008] All features disclosed in the description and / or claims are intended to be disclosed separately and independently of each other for the purpose of the original written disclosure and for the purpose of limiting the claimed subject matter, regardless of the combinations of features in the embodiments and / or the claims. Furthermore, any ranges of values ​​or indications of groups of entities are intended to disclose all possible intermediate values ​​or intermediate entities for the purpose of the original written disclosure and for the purpose of limiting the claimed subject matter.

[0009] In one or more embodiments, the cart may further comprise a steering mechanism configured to steer at least one of the wheels as a steered wheel.

[0010] A cart with a steering mechanism is more likely to pull or sway a user during a turning motion, as it can perform the turning motion without sufficiently reducing the vehicle's speed. The above configuration prevents the user from being pulled or swayed when the cart incorporating the steering mechanism performs the turning motion.

[0011] In one or more embodiments, the handle may be supported by the vehicle body so as to be rotatable about a rotation axis and configured to be rotated by the user. The cart may further include a handle angle sensor configured to detect a rotation angle of the handle about the rotation axis as a handle angle. The control unit may be configured to set a target steering angle of the steered wheel for the turning movement based on the handle angle. The control unit may be configured to set the target vehicle speed for the turning movement based on the handle angle.

[0012] When the cart performs a turning movement according to the user's handle rotation, the larger the handle angle, the smaller the turning radius of the vehicle body, whereas the smaller the handle angle, the larger the turning radius of the vehicle body. The above configuration utilizes a simple structure that allows a slower target vehicle speed to be set for a turning movement where the turning radius of the vehicle body is small compared to the target vehicle speed for a turning movement where the turning radius of the vehicle body is large.

[0013] In one or more embodiments, the control unit may be configured to calculate the target vehicle speed as a linear function of the grip angle.

[0014] The above configuration allows a reduction of the processing load of the control unit.

[0015] In one or more embodiments, the drive unit may comprise a plurality of motors each corresponding to the wheels.

[0016] The above configuration allows for easy adjustment of the vehicle speed when the car performs a turning movement.

[0017] (Embodiment) A Fig. 1 comprises a vehicle body 4, a load-carrying platform 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 load-carrying platform 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 cart 2 carries a load on the load-carrying platform 6. The cart 2 comprises a wireless interface (I / F) 18 (see Fig. 2) mounted on the vehicle body 4. The cart 2 is configured to selectively operate in a manual mode, an autonomous mode, and a parking mode. In the manual mode, the cart 2 moves forward or backward depending on the operation of a user standing behind the vehicle body 4 and grasping the handle 8 with both hands. In the autonomous mode, the cart 2 performs a tracking operation in which the cart 2 follows a beacon (not shown) worn by the user standing in front of the vehicle body 4, and a remote-controlled operation in which the cart 2 moves according to instructions from a remote control (not shown) operated by the user. In this mode, the cart 2 receives radio waves from the beacon and the remote control via the wireless I / F 18. In the parking mode, the cart 2 remains stationary without accepting instructions from the handle 8, the beacon, or the remote control.

[0018] The carriage 2 comprises a battery holder 20 on the vehicle body 4. The battery holder 20 is configured to accommodate a battery pack 22 (see Fig. 2) can be removably attached thereto. The battery pack 22 includes secondary battery cells (not shown), such as lithium-ion battery cells, and is configured to be recharged using a charger (not shown). The cart 2 is powered by electrical energy supplied by the battery pack 22 attached to the battery receptacle 20.

[0019] As in Fig. As shown in Figure 2, the carriage 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.

[0020] As in Fig. As shown in Figure 1, the handle 8 is rotatable relative to the vehicle body 4 about a rotation axis extending in an up-down direction. The user can rotate the handle 8 while gripping the handle 8 with both hands. As shown in Fig. As shown in Figure 2, the cart 2 includes a handle angle sensor 32 configured to detect a rotation angle of the handle 8 as a handle angle, a steering mechanism 34 configured to steer the right front wheel 10 and the left front wheel 12 as steered wheels, and a steering motor 36 configured to drive 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.

[0021] As in Fig. 1, there is a control box 38 on the handle 8. As shown in Fig. As shown in Figure 2, a main power switch 40, a mode switch 42, a trigger switch 44, a movement direction switch 46, and a speed switch 48 are located on the control box 38. The main power switch 40 is used to turn the main power supply of the cart 2 on and off. The mode switch 42 is used to switch the operation mode of the cart 2 between manual mode, autonomous mode, and parking mode. The trigger switch 44 is used in manual mode to turn the forward and reverse movements of the cart 2 on and off and to adjust the movement speed of the cart 2. The movement direction switch 46 is used in manual mode to change the movement direction of the cart 2. The speed switch 48 is used in manual mode to change the movement speed of the cart 2.The user can operate the main power switch 40, the mode switch 42, the trigger switch 44, the movement direction switch 46 and the speed switch 48 while gripping the handle 8 with both hands.

[0022] The carriage 2 includes a control power circuit 50 and a control unit 52. The control circuit 50 enables the supply of electric power from the battery pack 22 in response to an on-operation received by the main power switch 40, while preventing the supply of electric power from the battery pack 22 in response to an off-operation received by the main power switch 40. The control unit 52 controls the carriage 2. The control unit 52 controls 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 via motor drivers 54, 56, 58, 60 and 62, respectively. Brake circuits 64, 66, 68 and 70 are connected to the motor drivers 54, 56, 58 and 62, respectively.60, which correspond 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 can exert a large control force on 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 by allowing a large current to flow through the brake circuits 64, 66, 68, and 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. The control 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.

[0023] (Turning movement process) The control unit 52 carries out a Fig. 3 when the main power of the carriage 2 is turned on and the manual mode is selected.

[0024] In S2, the control unit 52 detects a grip angle of the handle 8 via the handle angle sensor 32.

[0025] In S4, the control unit 52 determines a target steering angle for the right front wheel 10 and the left front wheel 12 based on the grip angle detected in S2.

[0026] In S6, the control unit 52 determines a target vehicle speed for the turning movement based on the grip angle detected in S2.

[0027] In S8, the control unit 52 controls the steering motor 36 to operate the steering mechanism 34 based on the target steering angle determined in S4, and further 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 to operate the right front wheel 10, the left front wheel 12, the right rear wheel 14, and the left rear wheel 16 based on the target vehicle speed determined in S6. Thus, the car 2 performs a turning movement with the right front wheel 10 and the left front wheel 12 angled by the target steering angle determined in S4 and the speed of the vehicle body 4 at the target vehicle speed determined in S6. After S8, the process returns to S2.

[0028] (Control or regulation of the vehicle speed for the turning movement) Fig. Fig. 4 shows a relationship between a vehicle speed Vb, which is the speed of the vehicle body 4, and a user speed Vu, which is the speed of a user U, during a turning movement of the car 2. In the Fig. In the example shown in Figure 4, the user U turns the handle 8 clockwise in plan view, and therefore the cart 2 performs a right turn around a turning center Cr. In this case, a turning radius Ru of the user U is larger than a turning radius Rb of the vehicle body 4, and therefore the user speed Vu during the turning movement is faster than the vehicle speed Vb. In particular, the following relationship applies: Vu = Vb × Ru / Rb. As Fig. 4 clearly shows, Ru / Rb takes a larger value for a smaller turning radius Rb of the vehicle body 4, while Ru / Rb takes a smaller value approaching a value of “1” for a larger turning radius Rb of the vehicle body 4.

[0029] Fig. Figure 5 shows an exemplary relationship between the curvature of the turning motion of the car 2 (inverse of the turning radius Rb of the vehicle body 4), the vehicle speed Vb and the user speed Vu. In the Fig. In the example shown in Figure 5, the vehicle speed Vb is kept constant regardless of the curvature of the turning movement. In this case, the user speed Vu takes a value close to that of the vehicle speed Vb when the curvature of the turning movement is small (i.e., the turning radius Rb is large), whereas the user speed Vu takes a value greater than that of the vehicle speed Vb when the curvature of the turning movement is large (i.e., the turning radius Rb is small). Therefore, when the cart 2 performs a turning movement with a large curvature (i.e., with a small turning radius Rb), the user walking behind the vehicle body 4 and grasping the handle 8 will be pulled or swayed by this turning movement.

[0030] Fig. Figure 6 shows another exemplary relationship between the curvature of the turning motion of the car 2, the vehicle speed Vb and the user speed Vu. In the Fig. In the example shown in Figure 6, the vehicle speed Vb is reduced as the curvature of the turning movement increases (i.e., as the turning radius Rb decreases). In this case, the user speed Vu can be kept constant regardless of the curvature of the turning movement. Therefore, even if the cart 2 performs a turning movement with a large curvature (i.e., with a small turning radius Rb), the user walking behind the vehicle body 4 and grasping the handle 8 will not be pulled or swayed.

[0031] In the cart 2 according to this embodiment, a larger grip angle of the handle 8 leads to a larger steering angle of the steered wheels, which is adjusted by the steering mechanism 34, and thus to a larger curvature of the turning movement of the cart 2. Conversely, a smaller grip angle of the handle 8 leads to a smaller steering angle of the steered wheels, which is adjusted by the steering mechanism 34, and thus to a smaller curvature of the turning movement of the cart 2. Therefore, even if the horizontal axes of the graphs in Fig. 5 and Fig. 6 are replaced by grip angle or steering angle, the same relationship between vehicle speed Vb and user speed Vu.

[0032] As in Fig. 7, the control unit 52 in this embodiment calculates a target vehicle speed Vb as a function of the grip angle (see S6 in Fig. 3) to make the user speed Vu constant during a turning movement. Fig. Figure 7 shows relationships between the grip angle and the target vehicle speed Vb for cases where the moving speed of the carriage 2 is low, medium, and high, respectively; however, the same relationships apply to speeds depending on how strongly the trigger switch 44 is operated. In the Fig. 7, the smaller the grip angle (i.e., the smaller the steering angle / the smaller the curvature during the turning movement / the larger the turning radius of the vehicle body 4), the higher the target vehicle speed Vb during the turning movement. Conversely, the larger the grip angle (i.e., the larger the steering angle / the greater the curvature during a turning movement / the smaller the turning radius of the vehicle body 4), the lower the target vehicle speed Vb during the turning movement. By setting the target vehicle speed Vb in this way, it is possible to prevent the user walking behind the vehicle body 4 and grasping the handle 8 when the cart 2 turns from being pulled or swayed. Instead of calculating the target vehicle speed Vb as a function of the steering angle, the steering orControl unit 52 calculates the target vehicle speed Vb as a function of the steering angle, calculates the target vehicle speed Vb as a function of the curvature of the turning movement or calculates the target vehicle speed Vb as a function of the turning radius of the vehicle body 4 in S6 of . Fig. 3 calculate.

[0033] As in Fig.As shown in Figure 7, in order to make the user speed Vu constant, the target vehicle speed Vb can be approximately calculated using a linear function of the grip angle (or a linear function of the steering angle, or a linear function of the curvature of the turning movement). Thus, in the cart 2 according to this embodiment, the control unit 52 calculates the target vehicle speed Vb using the linear function of the grip angle. For example, the target vehicle speed Vb is calculated by Vb = Vb0 × (1 - A × θ / θmax), where Vb0 is a vehicle speed when the cart 2 is traveling straight, θ is a grip angle, θmax is the maximum grip angle (constant), and A is a positive constant. This configuration can reduce the processing load of the control unit 52.

[0034] The above describes how the control unit 52 controls the vehicle speed for the turning movement while the carriage 2 is moving forward. However, the control unit 52 can control the vehicle speed in the same way while the carriage 2 is moving backward.

[0035] (Variations) In the above 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 or hub 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, respectively.

[0036] In the above 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 be DC brush motors, AC motors or other types of motors.

[0037] In the above embodiment, the steering mechanism 34 may be actuated not by the steering motor 36 but by an actuator of another type.

[0038] In the above embodiment, the right front wheel 10, the left front wheel 12, the right rear wheel 14 and / or the left rear wheel 16 may be driven not by 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, but by an internal combustion engine.

[0039] In the above embodiment, the carriage 2 may be powered not from the battery pack 22 but from a power supply arranged outside the carriage 2 via a power cable.

[0040] As above, in one or more embodiments, the cart 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 (example of wheels) supported by the vehicle body and configured to be 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) configured to 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 configured to be grasped by the user walking behind the vehicle body 4; and the control unit 52 configured to control 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 car 2 performs a turning movement, the control unit 52 sets a slower target vehicle speed for a turning movement in which the turning radius of the vehicle body is small, compared to a target vehicle speed for a turning movement in which the turning radius of the vehicle body is large.

[0041] The above configuration makes it possible to reduce the speed of the vehicle body 4 for a turning movement where the turning radius of the vehicle body 4 is smaller. This prevents the user's speed from increasing when the cart 2 performs the turning movement. Thus, it is possible to prevent the user from being dragged or swayed when the cart 2 performs the turning movement.

[0042] In one or more embodiments, the cart 2 further includes the steering mechanism 34 configured to steer the right front wheel 10 and the left front wheel 12 as steered wheels.

[0043] A cart 2 with the steering mechanism 34 is more likely to pull or sway a user during a turning movement because it can perform the turning movement without sufficiently reducing the vehicle speed. The above configuration prevents the user from being pulled or swayed when the cart 2 including the steering mechanism 34 performs a turning movement.

[0044] In one or more embodiments, the handle 8 is supported by the vehicle body 4 so as to be rotatable about the rotation axis and is configured to be rotated by the user. The cart 2 further includes the handle angle sensor 32, which is configured to detect a rotation angle of the handle 8 about the rotation axis as a handle angle. The control unit 52 is configured to set a target steering angle of the steered wheels for the turning movement based on the handle angle. The control unit 52 is configured to set the target vehicle speed for the turning movement based on the steering angle.

[0045] When the cart 2 performs a turning movement according to the rotation of the handle 8 performed by the user, the larger the handle angle, the smaller the turning radius of the vehicle body 4, whereas the smaller the handle angle, the larger the turning radius of the vehicle body 4. The above configuration allows, with a simple structure, to set a slower target vehicle speed for a turning movement in which the turning radius of the vehicle body 4 is small than a target vehicle speed for a turning movement in which the turning radius of the vehicle body 4 is large.

[0046] In one or more embodiments, the control unit 52 is configured to calculate the desired vehicle speed as a linear function of the grip angle.

[0047] The above configuration enables a reduction of the processing load of the control unit 52.

[0048] 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 correspond to the right front wheel 10, the left front wheel 12, the right rear wheel 14, and the left rear wheel 16, respectively.

[0049] The above configuration allows easy adjustment of the speed of the vehicle body 4 when the carriage 2 performs a turning movement. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2000-78708

[0002]

Claims

[1] Carriage (2), comprising: a vehicle body (4); Wheels (10, 12, 14, 16) supported by the vehicle body (4) and configured to be in contact with a ground; a primary drive or drive unit (24, 26, 28, 30) configured to drive the wheels (10, 12, 14, 16); a handle (8) configured to be gripped by a user walking behind the vehicle body (4); and a control or regulating unit (52) configured to control or regulate operation of the drive unit (24, 26, 28, 30), where when the vehicle (2) performs a turning movement, the control or regulating unit is configured to set a slower target vehicle speed for a turning movement in which a turning radius of the vehicle body (4) is small, compared to a target vehicle speed for a turning movement in which a turning radius of the vehicle body (4) is large. [2] The cart (2) of claim 1, further comprising a steering mechanism (34) configured to steer at least one of the wheels (10, 12, 14, 16) as a steered wheel. [3] Cart (2) according to claim 2, wherein the handle (8) is supported by the vehicle body (4) so ​​as to be rotatable about a rotation axis and is configured to be rotated by the user, the carriage (2) further comprises a handle angle sensor (32) configured to detect a rotation angle of the handle (8) about the rotation axis as a handle angle, the control unit (52) is configured to set a target steering angle of the steered wheel for the turning movement based on the grip angle, and the control or regulating unit (52) is configured to set the target vehicle speed for the turning movement based on the steering angle. [4] Cart (2) according to claim 3, wherein the control unit 52 is configured to calculate the target vehicle speed as a linear function of the grip angle. [5] Carriage (2) according to one of claims 1 to 4, wherein the drive unit (24, 26, 28, 30) comprises a plurality of motors (24, 26, 28, 30) each provided corresponding to the wheels (10, 12, 14, 16).

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