Double-motor-driven trolley and turning control method thereof

Abstract

The invention discloses a dual-motor-driven trolley and a turning control method thereof, and relates to the technical field of trolleys. The dual-motor-driven trolley comprises a bearing plate, and the upper plate surface of the bearing plate is a placement surface; the driving mechanism comprises a left driving wheel set, a left driving motor, a right driving wheel set and a right driving motor; the left driving wheel set and the right driving wheel set are symmetrically arranged in the middles of the two sides of the bearing plate in the width direction. The left driving motor and the right driving motor are mounted on the lower plate surface of the bearing plate, are correspondingly connected and drive the left driving wheel set and the right driving wheel set to rotate; a front universal wheel and a rear universal wheel; front universal wheels are mounted in the middle of the front side of the lower plate surface of the bearing plate; the rear universal wheel is mounted in the middle of the rear side of the lower plate surface of the bearing plate; and the controller is electrically connected with the left driving motor and the right driving motor to control the left driving motor and the right driving motor to rotate and further control advancing and steering of the bearing plate. The two motors are independently controlled to drive the two wheel sets of the trolley to advance, and steering control is more flexible and accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of small vehicles, and in particular to a small vehicle driven by dual motors and a turning control method thereof. Background Art

[0002] In the field of automated control systems, cars, as a basic mobile platform, are widely used in logistics, automated production lines, service robots and other scenarios. Traditional car turning methods are usually through four-wheel steering, Mecanum wheel steering, adding gyroscope steering, etc. However, these methods have some shortcomings: for four-wheel steering, due to the addition of an additional steering mechanism, maintenance and repair may be more complicated and expensive, four-wheel steering systems are usually more complicated and more expensive than traditional two-wheel steering systems, and additional steering mechanisms will increase the weight of the car, affecting efficiency and performance; for Mecanum wheel steering, the manufacturing process of Mecanum wheels is more complicated and more expensive than traditional wheels, and due to the special design of Mecanum wheels, the wheels may wear unevenly and require more frequent maintenance; for the method of adding gyroscope steering, the gyroscope is a high-precision sensor with a relatively high cost, and the integrated gyroscope requires complex control systems and algorithms, which increases the difficulty of system design and implementation, and the gyroscope needs to be calibrated regularly to maintain accuracy, which increases maintenance work.

[0003] In view of the above problems, although there have been some attempts to improve the performance of the car by improving the control algorithm, these methods often increase the complexity and cost of the system and have limited effects. The present invention aims to provide a dual-motor driven car and a turning control method thereof, which can achieve more flexible and precise steering control by independently controlling two motors to drive the two wheels of the car, thereby overcoming the limitations of the prior art. Summary of the invention

[0004] In view of this, the present invention proposes a dual-motor driven vehicle and a turning control method thereof, aiming to solve the technical problems of the above-mentioned traditional vehicle having a complex driving structure, high manufacturing and maintenance costs, inflexible steering and poor control accuracy.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] In one aspect, the present invention provides a dual-motor driven vehicle, comprising:

[0007] A load-bearing plate, the upper plate surface of which is a placement surface for placing goods to be transported, and the length direction of which is the front-to-back direction of operation;

[0008] A driving mechanism, the driving mechanism comprising a left driving wheel group, a left driving motor, a right driving wheel group and a right driving motor; the left driving wheel group and the right driving wheel group are symmetrically arranged on both sides of the width direction of the carrying plate and correspond to the middle part of the front-rear direction of the carrying plate; the left driving motor and the right driving motor are both installed on the lower plate surface of the carrying plate and are in one-to-one transmission connection and drive the left driving wheel group and the right driving wheel group to rotate;

[0009] Front universal wheel and rear universal wheel; the front universal wheel is installed on the front side of the lower plate of the bearing plate and corresponds to the middle of the width direction of the bearing plate; the rear universal wheel is installed on the rear side of the lower plate of the bearing plate and corresponds to the middle of the width direction of the bearing plate;

[0010] A controller is electrically connected to the left drive motor and the right drive motor to control their rotation, thereby controlling the travel and steering of the carrier plate.

[0011] The left driving wheel group and the right driving wheel group of the present invention are located on the left and right sides of the load-bearing plate, and the left driving motor, the right driving motor, the front universal wheel and the rear universal wheel are all arranged on the lower plate surface of the load-bearing plate. The spatial layout does not interfere with the placement surface of the load-bearing plate, which can make the placement surface of the load-bearing plate more conducive to loading goods. The front universal wheel and the left driving wheel group and the right driving wheel group together constitute a triangular support driving wheel combination structure 1, and the rear universal wheel and the left driving wheel group and the right driving wheel group together constitute a triangular support driving wheel combination structure 2. The triangular support driving wheel combination structure 1 and the triangular support driving wheel combination structure 2 are both triangular support combination layouts of double driving wheels plus a single universal wheel, which makes the overall steering drive of the trolley more flexible and can improve the stability and flexibility of the trolley when traveling and turning; and no matter whether the placement surface is loaded with goods at the front, back or in the middle, and whether the trolley accelerates or decelerates during travel, smooth travel can be ensured. The present invention controls the left drive motor and the right drive motor, thereby independently controlling the rotation speed and travel direction of the left drive wheel group and the right drive wheel group, which is conducive to achieving more flexible and precise steering control, and can achieve zero turning radius for on-the-spot turning and U-turn, while reducing the complexity and cost of the steering drive structure of the trolley, thereby reducing the manufacturing and maintenance costs of the trolley.

[0012] As a further improvement of the above technical solution, the driving mechanism also includes a left transmission rod and a right transmission rod; one end of the left transmission rod is transmission connected to the left driving motor, and the other end is transmission connected to the left driving wheel group; one end of the right transmission rod is transmission connected to the right driving motor, and the other end is transmission connected to the right driving wheel group.

[0013] As a further improvement of the above technical solution, the left driving wheel group includes multiple left driving wheels, the multiple left driving wheels are coaxially arranged and are all coaxially connected to one end of the left transmission rod; the right driving wheel group includes multiple right driving wheels, the multiple right driving wheels are coaxially arranged and are all coaxially connected to one end of the right transmission rod; the left transmission rod and the right transmission rod are coaxially arranged.

[0014] The beneficial effect of the above technical solution is that the coaxially arranged multiple left drive wheels and the coaxially arranged multiple right drive wheels can increase the friction with the ground, and can improve the stability of the vehicle's travel and steering drive.

[0015] As a further improvement of the above technical solution, the plurality of left driving wheels and the plurality of right driving wheels are rubber wheels.

[0016] As a further improvement of the above technical solution, the supporting plate includes a main supporting plate, a convex plate 1 and a convex plate 2; the convex plate 1 and the convex plate 2 are symmetrically fixed at the front and rear ends of the main supporting plate and correspond to the middle part of the width direction of the main supporting plate; the front universal wheel is installed on the lower plate surface of the convex plate 1; the rear universal wheel is installed on the lower plate surface of the convex plate 2.

[0017] The beneficial effect of the above technical solution is that the front universal wheel, the rear universal wheel, the left drive wheel group and the right drive wheel group are all arranged corresponding to the peripheral side of the main load-bearing plate, which can improve the stability of the trolley loaded with goods.

[0018] Another aspect of the present invention provides a turning control method for a dual-motor driven vehicle, including the following turning control modes:

[0019] Mode 1: The controller controls the rotation speed of the left drive motor and the right drive motor, thereby driving the left drive wheel set and the right drive wheel set to move in opposite directions at the same speed, so that the steering center of the trolley corresponds to the axial midpoint of the left drive wheel set and the right drive wheel set, so as to realize the in-situ steering of the trolley;

[0020] Mode 2: The controller controls the rotation of the left drive motor and the right drive motor, and then controls the left drive wheel group and the right drive wheel group to move in opposite or same directions at different speeds, so as to control the car to make a turning movement with a turning radius r; the turning radius r is the distance from the axial midpoint of the left drive wheel group and the right drive wheel group to the steering center of the car.

[0021] As a further improvement of the above technical solution, in mode 1, the rotating shaft of the left driving motor is coaxially fixedly connected to one end of the left transmission rod, and the other end of the left transmission rod is coaxially fixedly connected to the axle of the left driving wheel set; the rotating shaft of the right driving motor is coaxially fixedly connected to one end of the right transmission rod, and the other end of the right transmission rod is coaxially fixedly connected to the axle of the right driving wheel set;

[0022] The radius of the left driving wheel group and the right driving wheel group are both set to R, and the distance between them is set to L; the left driving motor and the right driving motor are both motors with encoders; the controller is a PID controller; the number of pulse signals required for the left driving motor and the right driving motor to rotate one circle is N;

[0023] Then the relationship between the desired angle α of the car's rotation and the number of pulse signals required by the left drive motor and the right drive motor is: The target pulse signal number T can be obtained according to the desired angle α, and the pulse signal number T is sent to the left drive motor and the right drive motor through the PID controller, so that the left drive wheel group and the right drive wheel group move in opposite directions at the same speed, thereby realizing the rotation of the car to the desired angle α.

[0024] As a further improvement of the above technical solution, in mode 2, when the car is controlled to make a turning motion with a turning radius r and r is less than L, the left driving wheel set is controlled by the PID controller to move at a desired speed V1 and the right driving wheel set is controlled to move at a desired speed V2 in opposite directions; The distance between the steering center and the left driving wheel set 21 is r1, and the straight-line distance between the steering center and the right driving wheel set 23 is r2.

[0025] As a further improvement of the above technical solution, in mode 2, when the car is controlled to make a turning motion with a turning radius r and r is greater than L, the left driving wheel set is controlled by the PID controller to move at a desired speed V1 and the right driving wheel set is controlled to move at a desired speed V2 in the same direction with a differential speed; The distance between the steering center and the left driving wheel set 21 is r1, and the straight-line distance between the steering center and the right driving wheel set 23 is r2.

[0026] As a further improvement of the above technical solution, in mode 2, when the car is controlled to make a turning motion with a turning radius r and r is equal to L, only the left driving wheel group or the right driving wheel group is controlled to rotate through the PID controller;

[0027] Then the relationship between the desired angle α of the car's rotation and the number of pulse signals required by the left drive motor or the right drive motor is: The PID controller sends only a number of pulse signals T to the left drive motor or the right drive motor to make only the left drive wheel group or the right drive wheel group move, thereby realizing the rotation of the trolley to the desired angle α.

[0028] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses a dual-motor driven vehicle and a turning control method thereof, which has the following advantages and beneficial effects:

[0029] 1. The dual-motor driven trolley of the present invention has a simple structure and low manufacturing cost. The load-bearing plate serves as a drive structure mounting plate and a cargo consignment plate, has a simplified structure, light weight, and good flexibility. As a mobile platform, it can be widely used in multiple scenarios such as logistics transportation, automated production lines, and service robots.

[0030] 2. The rotation angle and speed of the left drive motor and the right drive motor of the present invention are controlled by a PID controller, and the left drive motor is coaxially directly connected to the left drive wheel group, and the right drive motor is coaxially directly connected to the right drive wheel group, so that the control logic is simplified and the accuracy of steering and travel control can be improved; the PID controller can realize the turning of the trolley along any turning radius by collaboratively controlling the rotation angle and speed of the left drive motor and the right drive motor, so that the dual-motor driven trolley can be suitable for handling operations in smaller spaces or channels. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0032] Figure 1 A three-dimensional schematic diagram of the overall structure of a dual-motor driven vehicle of the present invention;

[0033] Figure 2 A bottom view of a dual-motor driven trolley structure of the present invention;

[0034] Figure 3 A side view of a dual-motor driven trolley structure of the present invention;

[0035] Figure 4 A front view of a dual-motor driven trolley structure of the present invention;

[0036] Figure 5 A schematic diagram of equivalent analysis of the in-situ turning motion of a dual-motor driven trolley of the present invention;

[0037] Figure 6 A schematic diagram of a control process of in-situ steering motion of a dual-motor driven trolley of the present invention;

[0038] Figure 7 A schematic diagram of equivalent analysis of steering motion of a dual-motor driven vehicle according to the present invention, in which the steering center O is located between the left driving wheel set and the right driving wheel set;

[0039] Figure 8 A schematic diagram of a steering motion control process of a dual-motor driven vehicle according to the present invention, in which the steering center O is located between the left driving wheel set and the right driving wheel set;

[0040] Fig. 9 A schematic diagram of equivalent analysis of a steering motion of a dual-motor driven vehicle according to the present invention, in which the steering center O is located outside the relative direction of the left driving wheel set and the right driving wheel set;

[0041] Fig.10 A schematic diagram of a steering motion control process of a dual-motor driven vehicle according to the present invention, in which the steering center O is located outside the relative direction of the left driving wheel set and the right driving wheel set;

[0042] Fig.11 A schematic diagram of equivalent analysis of the steering motion of a dual-motor driven vehicle according to the present invention with the left driving wheel set or the right driving wheel set as the steering center O;

[0043] Fig.12 A schematic diagram of a control flow of a dual-motor driven vehicle according to the present invention for steering movement with the left driving wheel set or the right driving wheel set as the steering center O;

[0044] In the figure: 1. load-bearing plate; 11. main load-bearing plate; 111. placement surface; 12. convex plate 1; 13. convex plate 2; 2. driving mechanism; 21. left driving wheel set; 211. left driving wheel; 22. left driving motor; 23. right driving wheel set; 231. right driving wheel; 24. right driving motor; 25. left transmission rod; 26. right transmission rod; 3. front universal wheel; 4. rear universal wheel. DETAILED DESCRIPTION

[0045] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0046] In the description of the present invention, it is necessary to understand that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0047] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0048] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] According to an embodiment of the present invention, Figures 1 to 4 As shown, a dual-motor driven vehicle comprises:

[0050] The upper plate surface of the carrying plate 1 is a placement surface 111 for placing goods to be transported, and its length direction is the front-to-back direction of operation;

[0051] The driving mechanism 2 includes a left driving wheel set 21, a left driving motor 22, a right driving wheel set 23 and a right driving motor 24; the left driving wheel set 21 and the right driving wheel set 23 are symmetrically arranged on both sides of the width direction of the carrying plate 1 and correspond to the middle part of the front-back direction of the carrying plate 1; the housings of the left driving motor 22 and the right driving motor 24 are fixedly mounted on the lower plate surface of the carrying plate 1 and the rotating shafts thereof are connected in a one-to-one transmission manner and drive the left driving wheel set 21 and the right driving wheel set 23 to rotate;

[0052] Front universal wheel 3 and rear universal wheel 4; the front universal wheel 3 is installed on the front side of the lower plate of the load-bearing plate 1 and corresponds to the middle of the width direction of the load-bearing plate 1; the rear universal wheel 4 is installed on the rear side of the lower plate of the load-bearing plate 1 and corresponds to the middle of the width direction of the load-bearing plate 1;

[0053] The controller is electrically connected to the left driving motor 22 and the right driving motor 24 to control their rotation, thereby controlling the travel and steering of the carrying plate 1 .

[0054] The left driving wheel set 21 and the right driving wheel set 23 of this embodiment are located on the left and right sides of the load-bearing plate 1, and the left driving motor 22, the right driving motor 24, the front universal wheel 3 and the rear universal wheel 4 are all arranged on the lower plate surface of the load-bearing plate 1, and the spatial layout does not interfere with the placement surface 111 of the load-bearing plate 1, so that the placement surface 111 of the load-bearing plate 1 can be more convenient for loading goods. The front universal wheel 3, the left driving wheel set 21 and the right driving wheel set 23 together form a triangular support driving wheel combination structure 1, and the rear universal wheel 4, the left driving wheel set 21 and the right driving wheel set 23 together form a triangular support driving wheel combination structure 2. Both the triangular support driving wheel combination structure 1 and the triangular support driving wheel combination structure 2 are triangular support combination layouts of double driving wheels plus a single universal wheel, which makes the overall steering drive of the trolley more flexible and can improve the stability and flexibility of the trolley when traveling and turning; and no matter whether the placement surface 111 is loaded with goods at the front, back or center, and whether the trolley accelerates or decelerates during travel, it can ensure smooth travel. The present invention controls the left drive motor 22 and the right drive motor 24, thereby independently controlling the rotation speed and travel direction of the left drive wheel group 21 and the right drive wheel group 23, which is conducive to achieving more flexible and precise steering control, and can achieve zero turning radius for on-the-spot turning and U-turn, while reducing the complexity and cost of the steering drive structure of the trolley, thereby reducing the manufacturing and maintenance costs of the trolley.

[0055] In some embodiments, the driving mechanism 2 also includes a left transmission rod 25 and a right transmission rod 26; one end of the left transmission rod 25 is transmission connected to the left driving motor 22, and the other end is transmission connected to the left driving wheel group 21; one end of the right transmission rod 26 is transmission connected to the right driving motor 24, and the other end is transmission connected to the right driving wheel group 23.

[0056] In some embodiments, the left driving wheel group 21 includes multiple left driving wheels 211, which are coaxially arranged and all coaxially connected to one end of the left transmission rod 25; the right driving wheel group 23 includes multiple right driving wheels 231, which are coaxially arranged and all coaxially connected to one end of the right transmission rod 26; the left transmission rod 25 and the right transmission rod 26 are coaxially arranged.

[0057] The coaxially arranged multiple left driving wheels 211 and the coaxially arranged multiple right driving wheels 231 can increase the friction with the ground, and improve the stability of the vehicle's travel and steering drive.

[0058] In some embodiments, the plurality of left driving wheels 211 and the plurality of right driving wheels 231 are rubber wheels.

[0059] In some embodiments, the supporting plate 1 includes a main supporting plate 11, a convex plate 12 and a convex plate 2 13; the convex plate 12 and the convex plate 2 13 are symmetrically fixed at the front and rear ends of the main supporting plate 11 and correspond to the middle part of the width direction of the main supporting plate 11; the front universal wheel 3 is installed on the lower plate surface of the convex plate 12; the rear universal wheel 4 is installed on the lower plate surface of the convex plate 2 13.

[0060] The front universal wheel 3, the rear universal wheel 4, the left driving wheel set 21 and the right driving wheel set 23 are all arranged corresponding to the peripheral side of the main bearing plate 11 to improve the stability of the trolley loaded with goods.

[0061] According to another embodiment of the present invention, a turning control method for a dual-motor driven vehicle includes the following turning control modes:

[0062] Mode 1: The controller controls the rotation speed and rotation angular displacement (i.e., the number of rotations) of the left drive motor 22 and the right drive motor 24, thereby driving the left drive wheel set 21 and the right drive wheel set 23 to move the same distance in opposite directions at the same speed, so that the steering center of the trolley corresponds to the axial midpoint of the left drive wheel set 21 and the right drive wheel set 23, so as to realize the in-situ steering of the trolley;

[0063] Mode 2: The controller controls the left drive motor 22 and the right drive motor 24 to rotate, and then controls the left drive wheel set 21 and the right drive wheel set 23 to move in opposite directions or in the same direction at different speeds, so as to control the trolley to make a turning movement with a turning radius r; the turning radius r is the distance from the axial midpoint of the left drive wheel set 21 and the right drive wheel set 23 to the steering center of the trolley.

[0064] In some embodiments, in mode 1, the rotating shaft of the left driving motor 22 is coaxially fixedly connected to one end of the left transmission rod 25, and the other end of the left transmission rod 25 is coaxially fixedly connected to the axle of the left driving wheel set 21; the rotating shaft of the right driving motor 24 is coaxially fixedly connected to one end of the right transmission rod 26, and the other end of the right transmission rod 26 is coaxially fixedly connected to the axle of the right driving wheel set 23;

[0065] The radius of the left driving wheel group 21 and the right driving wheel group 23 are both set to R, and the distance between them is set to L; the left driving motor 22 and the right driving motor 24 are both motors with encoders; the controller is a PID controller; the number of pulse signals required for the left driving motor 22 and the right driving motor 24 to rotate one circle is N;

[0066] Then the relationship between the desired angle α of the trolley's rotation and the number of pulse signals required by the left drive motor 22 and the right drive motor 24 is: Then, the target pulse signal number T can be obtained according to the desired angle α, and the pulse signal number T is sent to the left drive motor 22 and the right drive motor 24 through the PID controller, so that the left drive wheel set 21 and the right drive wheel set 23 move the same distance in the opposite direction at the same speed, thereby realizing the rotation of the trolley to the desired angle α. In other words, the pulse signal number T sent by the PID controller corresponds to the number of rotations of the left drive wheel set 21 and the right drive wheel set 23, and then the travel speed and position of the left drive wheel set 21 and the right drive wheel set 23 can be controlled by the pulse signal number T and the pulse signal frequency sent by the PID controller.

[0067] For details on the turning control method, see Figure 5 , Figure 5 The equivalent analysis diagram of the in-situ turning motion of the trolley is given. The rotation of the left drive motor 22, the left transmission rod 25 and the left drive wheel set 21 is always synchronized; the right drive motor 24, the right transmission rod 26 and the right drive wheel set 23 are always synchronized; the relationship between the unit distance of rotation of the left drive wheel set 21 and the right drive wheel set 23 and the corresponding number of pulse signals is: Further deduction is made so that when the trolley rotates to the desired angle α, the left driving wheel set 21 and the right driving wheel set 23 always rotate at the same speed V; when the trolley rotates, the midpoint of the line connecting the rotation center points of the left driving wheel set 21 and the right driving wheel set 23 is the center point of the trolley's turning rotation. According to the calculation method of arc length and radius, it can be deduced that when the trolley rotates to the desired angle α, the distance traveled by the left driving wheel set 21 and the right driving wheel set 23 is Therefore, the relationship between the required number of target pulse signals and the desired angle α of the car's rotation is T = |X|·Y, that is,

[0068] For details, see Figure 6 , the controller can be based on the desired angle α and To determine the number of pulse signals required to control the rotation of the left drive motor 22 and the right drive motor 24, thereby achieving precise on-the-spot steering control.

[0069] In some embodiments, in mode 2, when the car is controlled to make a turning motion with a turning radius r and r is less than L, the left driving wheel set 21 is controlled by the PID controller to move at a desired speed V1 and the right driving wheel set 23 is controlled to move at a desired speed V2 in opposite directions;

[0070] Specifically, a uniform circular motion around a point between the left driving wheel set 21 and the right driving wheel set 23 of the vehicle is taken as an example.

[0071] For analysis of the steering mode of the car, see Figure 7, the car performs uniform circular motion around the steering center O. Assume that the steering center O is close to the left driving wheel set 21. Assume that the speed of the left driving wheel set 21 is V1, the speed of the right driving wheel set 23 is V2, the distance between the steering center O and the left driving wheel set 21 is r1, the straight-line distance between the steering center O and the right driving wheel set 23 is r2, and the distance between the left driving wheel set 21 and the right driving wheel set 23 is L. Since the left driving wheel set 21 and the right driving wheel set 23 are installed on the same bearing plate 1 and both perform uniform circular motion, the time from the starting point to the end point of the motion process is the same. Assume that the motion time of the left driving wheel set 21 from the starting point to the end point is t1, and the motion time of the right driving wheel set 23 from the starting point to the end point is t2, then:

[0072]

[0073]

[0074] r2=L-r1

[0075] Obviously, t1 is equal to t2, so the following relationship can be obtained:

[0076]

[0077] Therefore, if you want to control the car to perform uniform circular motion around a point on the outside of the left driving wheel set 21 and the right driving wheel set 23 in the relative direction as the turning center O, it can be determined according to the relationship, see Figure 8 The controller can be used to control the left driving wheel set 21 to move at a desired speed V1 and the right driving wheel set 23 to move at a desired speed V2 in the same direction at a differential speed.

[0078] In some embodiments, in mode 2, when the car is controlled to make a turning motion with a turning radius r and r is greater than L, the left driving wheel set 21 is controlled by the PID controller to move at a desired speed V1 and the right driving wheel set 23 is controlled to move at a desired speed V2 in the same direction with a differential speed;

[0079] Specifically, a uniform circular motion is taken as an example around a point on the outside of the left driving wheel set 21 and the right driving wheel set 23 of the vehicle in relative directions.

[0080] For analysis of the steering mode of the car, see Fig. 9, the car performs uniform circular motion around the steering center O. Assume that the steering center O is close to the right driving wheel set 23. Assume that the speed of the right driving wheel set 23 is V1, the speed of the left driving wheel set 21 is V2, the distance between the steering center O and the right driving wheel set 23 is r1, the straight-line distance between the steering center O and the left driving wheel set 21 is r2, and the distance between the left driving wheel set 21 and the right driving wheel set 23 is L. Since the left driving wheel set 21 and the right driving wheel set 23 are installed on the same bearing plate 1 and both perform uniform circular motion, the time from the starting point to the end point of the motion process is the same. Assume that the motion time of the right driving wheel set 23 from the starting point to the end point is t1, and the motion time of the left driving wheel set 21 from the starting point to the end point is t2, then:

[0081]

[0082] r2=r1+L

[0083] Obviously, t1 is equal to t2, so the following relationship can be obtained:

[0084]

[0085] Therefore, if you want to control the car to perform uniform circular motion around a point on the outside of the left driving wheel set 21 and the right driving wheel set 23 in the relative direction as the turning center O, it can be determined according to the relationship, see Fig.10 The controller can be used to control the left driving wheel set 21 to move at a desired speed V1 and the right driving wheel set 23 to move at a desired speed V2 in the same direction at a differential speed.

[0086] In some embodiments, in mode 2, when the car is controlled to make a turning motion with a turning radius r and r is equal to L, only the left driving wheel set 21 or the right driving wheel set 23 is controlled to rotate through the PID controller;

[0087] The relationship between the desired angle α of the vehicle's rotation and the number of pulse signals required by the left drive motor 22 or the right drive motor 24 is: The PID controller sends only a pulse signal number T to the left drive motor 22 or the right drive motor 24 to make only the left drive wheel set 21 or the right drive wheel set 23 move, thereby realizing the rotation of the trolley to the desired angle α.

[0088] Specifically, when the right driving wheel set 23 is taken as a fixed point, the distance traveled by the left driving wheel set 21 when it rotates to the desired angle α is assumed to be X. According to the calculation formula of the arc length, the relationship between X and α can be obtained as follows:

[0089] X=αL

[0090] The relationship between the desired angle α and the number of pulse signals T required by the left drive motor 22 when rotating to the desired angle α is:

[0091]

[0092] See also Fig.12 , a PID controller is used to send a pulse signal number T to the left drive motor 22, thereby driving the left drive wheel set 21 to rotate and move to the desired angle α.

[0093] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0094] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A dual-motor driven vehicle, characterized in that: include: A load-bearing plate (1), wherein the upper plate surface of the load-bearing plate (1) is a placement surface (111) for placing goods to be transported, and the length direction of the load-bearing plate (1) is a front-rear direction of movement; A driving mechanism (2), the driving mechanism (2) comprising a left driving wheel group (21), a left driving motor (22), a right driving wheel group (23) and a right driving motor (24); the left driving wheel group (21) and the right driving wheel group (23) are symmetrically arranged on both sides of the width direction of the carrying plate (1) and correspond to the middle part of the front-rear direction of the carrying plate (1); the left driving motor (22) and the right driving motor (24) are both installed on the lower plate surface of the carrying plate (1) and are connected in a one-to-one transmission manner and drive the left driving wheel group (21) and the right driving wheel group (23) to rotate; A front universal wheel (3) and a rear universal wheel (4); the front universal wheel (3) is mounted on the front side of the lower plate of the carrier plate (1) and corresponds to the middle of the width direction of the carrier plate (1); the rear universal wheel (4) is mounted on the rear side of the lower plate of the carrier plate (1) and corresponds to the middle of the width direction of the carrier plate (1); A controller is electrically connected to the left drive motor (22) and the right drive motor (24) to control their rotation, thereby controlling the movement and steering of the carrier plate (1).

2. A dual-motor driven vehicle according to claim 1, characterized in that: The driving mechanism (2) further comprises a left transmission rod (25) and a right transmission rod (26); one end of the left transmission rod (25) is transmission-connected to the left driving motor (22), and the other end is transmission-connected to the left driving wheel set (21); one end of the right transmission rod (26) is transmission-connected to the right driving motor (24), and the other end is transmission-connected to the right driving wheel set (23).

3. A dual-motor driven vehicle according to claim 2, characterized in that: The left driving wheel group (21) comprises a plurality of left driving wheels (211), the plurality of left driving wheels (211) are coaxially arranged and are all coaxially connected to one end of the left transmission rod (25); the right driving wheel group (23) comprises a plurality of right driving wheels (231), the plurality of right driving wheels (231) are coaxially arranged and are all coaxially connected to one end of the right transmission rod (26); the left transmission rod (25) and the right transmission rod (26) are coaxially arranged.

4. A dual-motor driven vehicle according to claim 3, characterized in that: The plurality of left driving wheels (211) and the plurality of right driving wheels (231) are all rubber wheels.

5. A dual-motor driven vehicle according to claim 1, characterized in that: The bearing plate (1) comprises a main bearing plate (11), a convex plate 1 (12) and a convex plate 2 (13); the convex plate 1 (12) and the convex plate 2 (13) are symmetrically fixed at the front and rear ends of the main bearing plate (11) and correspond to the middle part of the width direction of the main bearing plate (11); the front universal wheel (3) is mounted on the lower plate surface of the convex plate 1 (12); and the rear universal wheel (4) is mounted on the lower plate surface of the convex plate 2 (13).

6. A turning control method for a dual-motor driven vehicle as claimed in any one of claims 1 to 5, characterized in that: Includes the following turn control modes: Mode 1: The controller controls the rotation of the left drive motor (22) and the right drive motor (24), thereby driving the left drive wheel set (21) and the right drive wheel set (23) to move in opposite directions at the same speed, so that the steering center of the vehicle corresponds to the axial middle point of the left drive wheel set (21) and the right drive wheel set (23), so as to realize the in-situ steering of the vehicle; Mode 2: The controller controls the rotation of the left drive motor (22) and the right drive motor (24), thereby controlling the left drive wheel set (21) and the right drive wheel set (23) to move in opposite directions or in the same direction at different speeds, so as to control the trolley to make a turning movement with a turning radius r; the turning radius r is the distance from the axial midpoint of the left drive wheel set (21) and the right drive wheel set (23) to the turning center of the trolley.

7. The turning control method of a dual-motor driven vehicle according to claim 6, characterized in that: In mode 1, the rotating shaft of the left driving motor (22) is coaxially fixedly connected to one end of the left transmission rod (25), and the other end of the left transmission rod (25) is coaxially fixedly connected to the axle of the left driving wheel group (21); the rotating shaft of the right driving motor (24) is coaxially fixedly connected to one end of the right transmission rod (26), and the other end of the right transmission rod (26) is coaxially fixedly connected to the axle of the right driving wheel group (23); The radius of the left driving wheel group (21) and the right driving wheel group (23) are both set to R, and the distance between them is set to L; the left driving motor (22) and the right driving motor (24) are both motors with encoders; the controller is a PID controller; the number of pulse signals required for the left driving motor (22) and the right driving motor (24) to rotate one circle is N; Then the relationship between the desired angle α of the trolley's rotation and the number of pulse signals required by the left drive motor (22) and the right drive motor (24) is: The target pulse signal quantity T can be obtained according to the desired angle α, and the pulse signal quantity T is sent to the left drive motor (22) and the right drive motor (24) through the PID controller, so that the left drive wheel group (21) and the right drive wheel group (23) move in opposite directions at the same speed, thereby realizing the rotation of the trolley to the desired angle α.

8. The turning control method of the dual-motor driven vehicle according to claim 7, characterized in that: In mode 2, when the car is controlled to make a turning motion with a turning radius r and r is less than L, the left driving wheel set (21) is controlled by the PID controller to move at a desired speed V1 and the right driving wheel set (23) is controlled to move at a desired speed V2 in opposite directions; The distance between the steering center and the left driving wheel set 21 is r1, and the straight-line distance between the steering center and the right driving wheel set 23 is r2.

9. The turning control method of the dual-motor driven vehicle according to claim 7, characterized in that: In mode 2, when the car is controlled to make a turning motion with a turning radius r and r is greater than L, the left driving wheel set (21) is controlled by the PID controller to move at a desired speed V1 and the right driving wheel set (23) is controlled to move at a desired speed V2 in the same direction with a differential speed; The distance between the steering center and the left driving wheel set 21 is r1, and the straight-line distance between the steering center and the right driving wheel set 23 is r2.

10. The turning control method of a dual-motor driven vehicle according to claim 7, characterized in that: In mode 2, when the car is controlled to make a turning motion with a turning radius r and r is equal to L, the PID controller is used to control only the left driving wheel group (21) or the right driving wheel group (23) to rotate; Then the relationship between the desired angle α of the trolley rotation and the number of pulse signals required by the left drive motor (22) or the right drive motor (24) is: The PID controller sends only a pulse signal quantity T to the left drive motor (22) or the right drive motor (24) to make only the left drive wheel group (21) or the right drive wheel group (23) move, thereby realizing the rotation of the trolley to the desired angle α.

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