Tricycle steering control method, device, controller, vehicle, medium and product
By setting the front wheel of the tricycle as the driven wheel, and the left and right rear wheels as separate drive wheels, and by determining the wheel speed through a controller, the problem of limited steering angle of existing tricycles has been solved, achieving smooth steering at any angle and improving the vehicle's flexibility and safety.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANGHAI ECAR TECHNOLOGY CO LTD
- Filing Date
- 2026-02-13
- Publication Date
- 2026-06-23
Smart Images
Figure CN121778028B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of vehicle technology, and in particular to a steering control method, device, controller, vehicle, medium, and product for a three-wheeled vehicle. Background Technology
[0002] Unmanned tricycles have applications in various fields, such as cleaning and freight transportation.
[0003] In existing technologies, the two rear wheels of unmanned tricycles are driven by coaxial drive. At higher speeds and larger steering angles, the front wheels may experience "understeer," or front wheel slippage. For driving safety, the steering angle is usually limited.
[0004] In summary, existing tricycles, due to their coaxial rear wheel drive, can only steer at a relatively small steering angle. Summary of the Invention
[0005] The present application provides a method, device, controller, vehicle, medium, and product for controlling the steering of a three-wheeled vehicle, which addresses the problem that existing three-wheeled vehicles, due to coaxial rear wheel drive, can only steer at a small steering angle.
[0006] In a first aspect, embodiments of this application provide a steering control method for a tricycle, applied to a controller in a tricycle, wherein the front wheel of the tricycle is a driven wheel, and the left and right rear wheels of the tricycle are independently driven drive wheels, and the method includes:
[0007] Obtain the target steering direction, target steering angle, current vehicle speed, wheelbase, and track width;
[0008] The target vehicle speed is determined based on the target steering angle, the current vehicle speed, and a preset first vehicle speed threshold.
[0009] The fixed wheel steering angle is determined based on the wheelbase and the track width.
[0010] The left rear wheel speed and right rear wheel speed are determined based on the target steering direction, the fixed wheel steering angle, the wheelbase, the track width, the target steering angle, and the target vehicle speed.
[0011] The left and right rear wheels are controlled to roll according to the speed of the left and right rear wheels.
[0012] In one possible implementation, determining the target vehicle speed based on the target steering angle, the current vehicle speed, and a preset first vehicle speed threshold includes:
[0013] If the target turning angle is 90 degrees, then the target vehicle speed is determined to be 0.
[0014] If the target steering angle is less than 90 degrees, the target vehicle speed is determined based on the current vehicle speed, the preset first vehicle speed threshold, and the preset second vehicle speed threshold, wherein the preset second vehicle speed threshold is less than the preset first vehicle speed threshold.
[0015] In one possible implementation, determining the target vehicle speed based on the current vehicle speed, the preset first vehicle speed threshold, and the preset second vehicle speed threshold includes:
[0016] If the current vehicle speed is equal to 0, then the target vehicle speed is determined to be the preset second vehicle speed threshold.
[0017] If the current vehicle speed is greater than 0 and less than or equal to the preset first vehicle speed threshold, then the target vehicle speed is determined to be the current vehicle speed;
[0018] If the current vehicle speed is greater than the preset first vehicle speed threshold, then the target vehicle speed is determined to be the preset first vehicle speed threshold.
[0019] In one possible implementation, determining the left rear wheel speed and right rear wheel speed based on the target steering direction, the fixed wheel steering angle, the wheelbase, the track width, the target steering angle, and the target vehicle speed includes:
[0020] If the target steering angle is less than the fixed wheel steering angle, or if the target steering angle is greater than the fixed wheel steering angle but less than 90 degrees, then the left rear wheel speed and the right rear wheel speed are determined based on the target steering direction, the wheelbase, the track width, the target steering angle, and the target vehicle speed.
[0021] If the target steering angle is equal to the fixed wheel steering angle, then the left rear wheel speed and the right rear wheel speed are determined according to the target steering direction and the target vehicle speed.
[0022] If the target steering angle is equal to 90 degrees, then the left rear wheel speed and the right rear wheel speed are determined according to the target steering direction and the preset wheel speed, wherein the preset wheel speed is greater than 0.
[0023] In one possible implementation, determining the left rear wheel speed and the right rear wheel speed based on the target steering direction, the wheelbase, the track width, the target steering angle, and the target vehicle speed includes:
[0024] Based on the target steering direction, the wheelbase, the track width, and the target steering angle, determine the wheel speed ratio between the left rear wheel speed and the right rear wheel speed;
[0025] The sum of the left rear wheel speed and the right rear wheel speed is taken as twice the target vehicle speed.
[0026] The wheel speeds of the left and right rear wheels are calculated based on the wheel speed ratio and the sum of the wheel speeds.
[0027] In one possible implementation, determining the left rear wheel speed and the right rear wheel speed based on the target steering direction and the target vehicle speed includes:
[0028] If the target turning direction is left, then the speed of the left rear wheel is determined to be 0, and the speed of the right rear wheel is twice the target vehicle speed;
[0029] If the target turning direction is right, then the speed of the left rear wheel is determined to be twice the target vehicle speed, and the speed of the right rear wheel is 0.
[0030] In one possible implementation, determining the left rear wheel speed and the right rear wheel speed based on the target steering direction and the preset wheel speed includes:
[0031] If the target turning direction is left, then the left rear wheel speed is determined to be the opposite of the preset wheel speed, and the right rear wheel speed is the preset wheel speed;
[0032] If the target turning direction is right, then the left rear wheel speed is determined to be the preset wheel speed, and the right rear wheel speed is the opposite of the preset wheel speed.
[0033] In one possible implementation, if the front wheel is a driven wheel with controllable steering, the rotation of the front wheel is controlled according to the target steering direction and the target steering angle.
[0034] In one possible implementation, before controlling the rolling of the left and right rear wheels based on the left and right rear wheel speeds, the method further includes:
[0035] Based on the target steering direction, the target steering angle, and the correspondence between the angle and the adjustment coefficient, determine the adjustment coefficients for the left rear wheel and the right rear wheel;
[0036] Calculate the adjusted left rear wheel speed and the adjusted right rear wheel speed based on the left rear wheel adjustment coefficient, the right rear wheel adjustment coefficient, the left rear wheel speed, and the right rear wheel speed;
[0037] The step of controlling the rotation of the left and right rear wheels based on the speeds of the left and right rear wheels includes:
[0038] The left and right rear wheels are controlled to roll according to the adjusted left and right rear wheel speeds.
[0039] Secondly, embodiments of this application provide a three-wheeled vehicle steering control device, comprising:
[0040] The acquisition module is used to acquire the target steering direction, target steering angle, current vehicle speed, wheelbase, and track width.
[0041] The processing module is used to determine the target vehicle speed based on the target steering angle, the current vehicle speed, and a preset first vehicle speed threshold.
[0042] The processing module is also used to determine the fixed wheel steering angle based on the wheelbase and the track width;
[0043] The processing module is also used to determine the left rear wheel speed and the right rear wheel speed based on the target steering direction, the fixed wheel steering angle, the wheelbase, the track width, the target steering angle, and the target vehicle speed;
[0044] The control module is used to control the rolling of the left and right rear wheels according to the speed of the left rear wheel and the speed of the right rear wheel.
[0045] Thirdly, embodiments of this application provide a controller, including:
[0046] Processor, memory, communication interface;
[0047] The memory is used to store the executable instructions of the processor;
[0048] The processor is configured to execute the tricycle steering control method according to any one of the first aspects by executing the executable instructions.
[0049] Fourthly, embodiments of this application provide a three-wheeled vehicle, including:
[0050] Controller, front wheel, left rear wheel, and right rear wheel;
[0051] The front wheel of the tricycle is a driven swivel wheel, and the left and right rear wheels of the tricycle are independently driven drive wheels.
[0052] The controller is used to execute the tricycle steering control method described in any of the first aspects above.
[0053] Fifthly, embodiments of this application provide a readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the tricycle steering control method described in any of the first aspects.
[0054] Sixthly, embodiments of this application provide a computer program product, including a computer program, which, when executed by a processor, is used to implement the tricycle steering control method described in any of the first aspects.
[0055] The tricycle steering control method, device, controller, vehicle, medium, and product provided in this application embodiment utilize a design where the front wheel of the tricycle is the driven wheel, and the left and right rear wheels are independently driven driving wheels. After acquiring the target steering direction, target steering angle, current vehicle speed, wheelbase, and track width, the controller determines the target vehicle speed based on the target steering angle, current vehicle speed, and a preset first speed threshold; and determines the fixed wheel steering angle based on the wheelbase and track width. Then, based on the target steering direction, fixed wheel steering angle, wheelbase, track width, target steering angle, and target vehicle speed, the left and right rear wheel speeds are determined, and the left and right rear wheels are controlled to roll. In this solution, the two rear wheels are driven independently, and the wheel speeds of the two rear wheels are determined by the target steering direction, target steering angle, current vehicle speed, wheelbase, and track width, enabling steering at the target steering angle. This solution does not limit the target steering angle, allowing the tricycle to turn at any steering angle. Attached Figure Description
[0056] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.
[0057] Figure 1 A flowchart illustrating an embodiment of the tricycle steering control method provided in this application;
[0058] Figure 2 A schematic diagram of the wheels of the tricycle provided in this application;
[0059] Figure 3 The steering angle diagram provided for this application Figure 1 ;
[0060] Figure 4 The steering angle diagram provided for this application Figure 2 ;
[0061] Figure 5 The steering angle diagram provided for this application Figure 3 ;
[0062] Figure 6 The steering angle diagram provided for this application Figure 4 ;
[0063] Figure 7 The steering angle diagram provided for this application Figure 5 ;
[0064] Figure 8 The steering angle diagram provided for this application Figure 6 ;
[0065] Figure 9The steering angle diagram provided for this application Figure 7 ;
[0066] Figure 10 The steering angle diagram provided for this application Figure 8 ;
[0067] Figure 11 A flowchart illustrating Embodiment 2 of the three-wheeled vehicle steering control method provided in this application;
[0068] Figure 12 A schematic diagram of the structure of an embodiment of the tricycle steering control device provided in this application;
[0069] Figure 13 This is a schematic diagram of the structure of a controller provided in this application.
[0070] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation
[0071] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.
[0072] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.
[0073] Unmanned tricycles have applications in various fields, such as cleaning and freight transportation.
[0074] In existing technology, the two rear wheels of unmanned tricycles are driven by coaxial drive. At higher speeds and larger steering angles, the front wheels may experience "understeer," or front wheel slippage. For driving safety, the steering angle is usually limited. Because existing tricycles use coaxial drive for the rear wheels, they can only steer at relatively small steering angles.
[0075] To address the problems existing in the prior art, the inventors, during their research on tricycle steering control methods, discovered that the front wheels of the tricycle can be designated as driven wheels, while the left and right rear wheels can be designated as independently driven wheels. The target vehicle speed is determined based on the target steering angle, the current vehicle speed, and a preset first speed threshold; the fixed wheel steering angle is determined based on the wheelbase and track width. Furthermore, based on the target steering direction, the fixed wheel steering angle, wheelbase, track width, target steering angle, and target speed, the speeds of the left and right rear wheels are determined, and the left and right rear wheels are controlled to achieve steering at the target steering angle. Based on the above inventive concept, the tricycle steering control scheme of this application was designed.
[0076] The following provides an example illustrating the application scenarios of the tricycle steering control method provided in this application.
[0077] For example, in this application scenario, the tricycle is an unmanned tricycle used for sweeping. The front wheels of the tricycle are set as driven wheels and are swivel wheels, while the left and right rear wheels are set as independently driven drive wheels. The controller in the tricycle can determine whether turning is needed based on the set route and the current position, or based on the current environment. When turning is needed, the target turning angle and target turning direction can be determined.
[0078] In order to steer, the controller also needs to obtain the current vehicle speed, wheelbase, and track width.
[0079] Then, based on the target steering angle, the current vehicle speed, and the preset first vehicle speed threshold, the target vehicle speed is determined; based on the wheelbase and track width, the fixed wheel steering angle is determined.
[0080] It should be noted that the current vehicle speed and the target vehicle speed in this application are both speeds at the midpoint of the line connecting the center points of the two rear wheels.
[0081] Then, based on the target steering direction, fixed wheel steering angle, wheelbase, track width, target steering angle, and target vehicle speed, the speeds of the left and right rear wheels are determined.
[0082] Finally, the left and right rear wheels are controlled to roll based on their speeds. Since the front wheels are swivel wheels, when the two rear wheels roll at different speeds, the angle of the front wheels will automatically adjust to the target steering angle, and the steering direction will automatically adjust to the target steering direction.
[0083] It should be noted that the above scenario is only an example of an application scenario provided by the embodiments of this application. The embodiments of this application do not limit the actual form of the various devices included in the scenario, nor do they limit the interaction method between devices. In the specific application of the solution, it can be set according to actual needs.
[0084] The technical solution of this application will now be described in detail through specific embodiments. It should be noted that the following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.
[0085] Figure 1 This is a flowchart illustrating a first embodiment of the tricycle steering control method provided in this application. This embodiment describes how the controller determines the left and right rear wheel speeds based on the target steering direction, target steering angle, current vehicle speed, wheelbase, and track width, and then controls the rotation of the left and right rear wheels. The method in this embodiment can be implemented through software, hardware, or a combination of both. Figure 1 As shown, the steering control method for this tricycle specifically includes the following steps:
[0086] S101: Obtain the target steering direction, target steering angle, current vehicle speed, wheelbase, and track width.
[0087] For example, Figure 2 A schematic diagram of the wheels of the tricycle provided in this application, as shown below. Figure 2 As shown, the front wheel 21 is the driven wheel, the left rear wheel 22 is the driving wheel, the right rear wheel 23 is the driving wheel, and the left rear wheel 22 and the right rear wheel 23 are driven independently.
[0088] In this step, when the controller determines that a turn is required, it can obtain the target turning direction and the target turning angle. In order to achieve the turn, it is also necessary to obtain the current vehicle speed, wheelbase, and track width.
[0089] It should be noted that the target turning direction is left or right, the target turning angle is the turning angle of the front wheels, the track width is the distance between the center points of the left and right rear wheels, the line connecting the center points of the left and right rear wheels is the line connecting the rear wheels, and the wheelbase is the distance between the midpoint of the line connecting the center points of the front wheels and the rear wheels.
[0090] S102: Determine the target vehicle speed based on the target steering angle, current vehicle speed, and preset first vehicle speed threshold.
[0091] In this step, after the controller obtains the target steering direction, target steering angle, current vehicle speed, wheelbase, and track width, it needs to determine the target vehicle speed based on the target steering angle, current vehicle speed, and a preset first vehicle speed threshold in order to determine the speed during steering.
[0092] It should be noted that the target turning angle is greater than 0 degrees and less than or equal to 90 degrees.
[0093] Specifically, if the target steering angle is 90 degrees, it means that the steering center point is the midpoint of the line connecting the center points of the two rear wheels, and the target vehicle speed is determined to be 0.
[0094] If the target steering angle is less than 90 degrees, the target speed is determined based on the current vehicle speed, the preset first vehicle speed threshold, and the preset second vehicle speed threshold.
[0095] It should be noted that the preset second speed threshold is lower than the preset first speed threshold. The preset second speed threshold can be 10 km / h, 15 km / h, 20 km / h, etc., and the preset first speed threshold can be 35 km / h, 40 km / h, 45 km / h, etc. This application embodiment does not limit the preset second speed threshold and the preset first speed threshold; they can be determined according to actual circumstances.
[0096] If the current vehicle speed is 0, in order to achieve steering, the target vehicle speed is determined to be the preset second vehicle speed threshold.
[0097] If the current vehicle speed is greater than 0 and less than or equal to the preset first vehicle speed threshold, it means that turning at the current vehicle speed is safe, and the target vehicle speed is determined to be the current vehicle speed.
[0098] If the current vehicle speed is greater than the preset first vehicle speed threshold, it means that turning at the current vehicle speed is unsafe, and the target vehicle speed is determined to be the preset first vehicle speed threshold.
[0099] It should be noted that the target speed and the current speed in this application refer to the speed at the midpoint of the line connecting the center point of the left rear wheel and the center point of the right rear wheel.
[0100] S103: Determine the fixed wheel steering angle based on the wheelbase and track width.
[0101] In this step, after the controller obtains the target steering direction, target steering angle, current vehicle speed, wheelbase, and track width, it needs to determine the fixed wheel steering angle based on the wheelbase and track width in order to determine the wheel speed of the two rear wheels.
[0102] In this application, the steering center point is on the line connecting the two rear wheel center points, the line connecting the steering center point and the front wheel center point is perpendicular to the orientation of the front wheel, and the angle between the orientation of the front wheel and the orientation of the vehicle body is the target steering angle.
[0103] The fixed wheel steering angle is the steering angle of the front wheels when the steering center point is the left or right rear wheel.
[0104] According to the formula Calculate the steering angle of the fixed wheels, where, The wheelbase is represented by L, and the track width by B.
[0105] For example, Figure 3 The steering angle diagram provided for this application Figure 1 ,like Figure 3 As shown, the steering center point is the left rear wheel. According to geometric relationships, it can be known that... .
[0106] It should be noted that the execution order of steps S102 and S103 can be as follows: step S102 is executed first, followed by step S103; step S103 is executed first, followed by step S102; or steps S102 and S103 are executed simultaneously. This embodiment does not limit the execution order of steps S102 and S103, and it can be determined according to the actual situation.
[0107] S104: Determine the left rear wheel speed and right rear wheel speed based on the target steering direction, fixed wheel steering angle, wheelbase, track width, target steering angle, and target vehicle speed.
[0108] In this step, after the controller obtains the target vehicle speed and the fixed wheel steering angle, it determines the left rear wheel speed and the right rear wheel speed based on the target steering direction, the fixed wheel steering angle, the wheelbase, the track width, the target steering angle, and the target vehicle speed.
[0109] It should be noted that when the speed of the left rear wheel is positive, it means that the left rear wheel is rolling forward; when the speed of the left rear wheel is negative, it means that the left rear wheel is rolling backward. When the speed of the right rear wheel is positive, it means that the right rear wheel is rolling forward; when the speed of the right rear wheel is negative, it means that the right rear wheel is rolling backward.
[0110] Specifically, if the target steering angle is less than the fixed wheel steering angle, or if the target steering angle is greater than the fixed wheel steering angle but less than 90 degrees, then the left rear wheel speed and the right rear wheel speed are determined based on the target steering direction, wheelbase, track width, target steering angle, and target vehicle speed.
[0111] In other words, based on the target steering direction, wheelbase, track width, and target steering angle, determine the ratio of the left rear wheel speed to the right rear wheel speed. Take twice the target speed as the sum of the left and right rear wheel speeds. Calculate the left and right rear wheel speeds based on the ratio and the sum of the wheel speeds.
[0112] For example, Figure 4 The steering angle diagram provided for this application Figure 2 ,like Figure 4 As shown, when the target turning direction is left and the target turning angle is less than the fixed wheel turning angle, , Where k represents the wheel speed ratio, Indicates the speed of the left rear wheel. This indicates the speed of the right rear wheel, L represents the wheelbase, and B represents the track width. Indicates the target steering angle, s represents the wheel speed, Indicates the target vehicle speed. It can be determined that... , .
[0113] Since the angular velocity of the entire vehicle is the same, combined with the formula Where w represents angular velocity, v represents velocity, and r represents distance. The distance from the center point of the left rear wheel to the center point of the steering wheel is... The distance from the center point of the right rear wheel to the center point of the steering wheel is ,so The target speed is the distance between the midpoint of the line connecting the center points of the left and right rear wheels and the center point of the steering wheel. ,so .
[0114] For example, Figure 5 The steering angle diagram provided for this application Figure 3 ,like Figure 5 As shown, when the target turning direction is left and the target turning angle is greater than the fixed wheel turning angle but less than 90 degrees, , Where k represents the wheel speed ratio, Indicates the speed of the left rear wheel. This indicates the speed of the right rear wheel, L represents the wheelbase, and B represents the track width. Indicates the target steering angle, s represents the wheel speed, This indicates the target speed. Because the left rear wheel will roll backward, therefore... It is a negative value. This can be determined. , .
[0115] Since the angular velocity of the entire vehicle is the same, combined with the formula Where w represents angular velocity, v represents velocity, and r represents distance. The distance from the center point of the left rear wheel to the center point of the steering wheel is... The distance from the center point of the right rear wheel to the center point of the steering wheel is ,so The target speed is the distance between the midpoint of the line connecting the center points of the left and right rear wheels and the center point of the steering wheel. ,so .
[0116] For example, Figure 6 The steering angle diagram provided for this application Figure 4 ,like Figure 6 As shown, when the target turning direction is right and the target turning angle is less than the fixed wheel turning angle, , Where k represents the wheel speed ratio, Indicates the speed of the left rear wheel. This indicates the speed of the right rear wheel, L represents the wheelbase, and B represents the track width. Indicates the target steering angle, s represents the wheel speed, Indicates the target vehicle speed. It can be determined that... , .
[0117] Since the angular velocity of the entire vehicle is the same, combined with the formula Where w represents angular velocity, v represents velocity, and r represents distance. The distance from the center point of the left rear wheel to the center point of the steering wheel is... The distance from the center point of the right rear wheel to the center point of the steering wheel is ,so The target speed is the distance between the midpoint of the line connecting the center points of the left and right rear wheels and the center point of the steering wheel. ,so .
[0118] For example, Figure 7 The steering angle diagram provided for this application Figure 5 ,like Figure 7 As shown, when the target turning direction is right and the target turning angle is greater than the fixed wheel turning angle but less than 90 degrees, , Where k represents the wheel speed ratio, Indicates the speed of the left rear wheel. This indicates the speed of the right rear wheel, L represents the wheelbase, and B represents the track width. Indicates the target steering angle, s represents the wheel speed, This indicates the target speed. Because the right rear wheel rolls backward, therefore... It is a negative value. This can be determined. , .
[0119] Since the angular velocity of the entire vehicle is the same, combined with the formula Where w represents angular velocity, v represents velocity, and r represents distance. The distance from the center point of the left rear wheel to the center point of the steering wheel is... The distance from the center point of the right rear wheel to the center point of the steering wheel is ,so The target speed is the distance between the midpoint of the line connecting the center points of the left and right rear wheels and the center point of the steering wheel. ,so .
[0120] If the target steering angle is equal to the fixed wheel steering angle, then the left rear wheel speed and the right rear wheel speed are determined based on the target steering direction and the target vehicle speed.
[0121] In other words, if the target vehicle is turning left, the left rear wheel speed is set to 0, and the right rear wheel speed is set to twice the target speed. If the target vehicle is turning right, the left rear wheel speed is set to twice the target speed, and the right rear wheel speed is set to 0.
[0122] For example, Figure 8 The steering angle diagram provided for this application Figure 6 ,like Figure 8 As shown, Let L represent the target steering angle, L represent the wheelbase, and B represent the track width. When the target steering direction is left and the target steering angle equals the fixed wheel steering angle, the left rear wheel will not roll, so the left rear wheel speed is 0. The distance from the center point of the right rear wheel to the steering center point is B, and the distance from the midpoint of the line connecting the center points of the left and right rear wheels to the steering center point is... Therefore, the speed of the right rear wheel is twice the target speed.
[0123] For example, Figure 9 The steering angle diagram provided for this application Figure 7 ,like Figure 9 As shown, Let L represent the target steering angle, L represent the wheelbase, and B represent the track width. When the target steering direction is right and the target steering angle equals the fixed wheel steering angle, the right rear wheel will not roll, so the right rear wheel speed is 0. The distance from the center point of the left rear wheel to the steering center point is B, and the distance from the midpoint of the line connecting the center points of the left and right rear wheels to the steering center point is... Therefore, the speed of the left rear wheel is twice the target speed.
[0124] If the target steering angle is 90 degrees, then the left rear wheel speed and right rear wheel speed are determined according to the target steering direction and the preset wheel speed.
[0125] In other words, if the target turning direction is left, the left rear wheel speed is set to the opposite of the preset wheel speed, and the right rear wheel speed is set to the preset wheel speed. If the target turning direction is right, the left rear wheel speed is set to the preset wheel speed, and the right rear wheel speed is set to the opposite of the preset wheel speed.
[0126] For example, Figure 10 The steering angle diagram provided for this application Figure 8 ,like Figure 10 As shown, This represents the target steering angle, L represents the wheelbase, and B represents the track width. When the target steering angle is 90 degrees and the target steering direction is left, the left rear wheel rolls backward, its wheel speed is negative, and the distance from the center point of the left rear wheel to the steering center point is... The distance from the center point of the right rear wheel to the center point of the steering wheel is Therefore, the absolute values of the left rear wheel speed and the right rear wheel speed are equal, thus determining that the left rear wheel speed is the opposite of the preset wheel speed, and the right rear wheel speed is the preset wheel speed.
[0127] When the target turning direction is right, the right rear wheel rolls backward, and the wheel speed of the right rear wheel is negative. The distance from the center point of the left rear wheel to the center point of the turn is... The distance from the center point of the right rear wheel to the center point of the steering wheel is Therefore, the absolute values of the left rear wheel speed and the right rear wheel speed are equal, so the left rear wheel speed is determined to be the preset wheel speed, and the right rear wheel speed is the opposite of the preset wheel speed.
[0128] It should be noted that the preset wheel speed is greater than 0, and can be 10km / h, 15km / h, 20km / h, etc. This application embodiment does not limit the preset wheel speed, and it can be determined according to the actual situation.
[0129] S105: Controls the rolling of the left and right rear wheels based on the speeds of the left and right rear wheels.
[0130] In this step, after the controller obtains the speeds of the left and right rear wheels, it can control the left and right rear wheels to roll according to their speeds.
[0131] For the left rear wheel, when the left rear wheel speed is not zero, the wheel motor of the left rear wheel is controlled according to the speed of the left rear wheel to achieve the rolling of the left rear wheel. When the left rear wheel speed is zero, the left rear wheel is braked to make the left rear wheel speed zero.
[0132] The control method for the right rear wheel is similar, so it will not be described in detail here.
[0133] It should be noted that driven wheels are divided into controllable steering driven wheels and swivel wheels. When the front wheels are controllable steering driven wheels, the controller controls the rotation of the front wheels according to the target steering direction and target steering angle, so that the steering direction of the front wheels is the target steering direction and the steering angle is the target steering angle.
[0134] When the front wheels are omnidirectional wheels, since the omnidirectional wheels support 360-degree omnidirectional rotation and have no steering angle limitation, when the two rear wheels are rolling at different wheel speeds, the steering angle of the front wheels will automatically adjust to the target steering angle, and the steering direction will automatically adjust to the target steering direction.
[0135] The tricycle steering control method provided in this embodiment uses a design where the front wheels are driven wheels and the left and right rear wheels are independently driven wheels. After acquiring the target steering direction, target steering angle, current speed, wheelbase, and track width, the controller determines the target speed based on the target steering angle, current speed, and a preset first speed threshold. It then determines the fixed-wheel steering angle based on the wheelbase and track width. Furthermore, based on the target steering direction, fixed-wheel steering angle, wheelbase, track width, target steering angle, and target speed, the controller determines the left and right rear wheel speeds and controls their rotation. In this scheme, the two rear wheels are driven independently, and their speeds are determined by the target steering direction, target steering angle, current speed, wheelbase, and track width, enabling steering at the target steering angle. This scheme does not limit the target steering angle, allowing the tricycle to turn at any steering angle, thus making the turning radius unrestricted.
[0136] Figure 11 This is a flowchart illustrating a second embodiment of the tricycle steering control method provided in this application. Based on the above embodiments, this application describes how the controller adjusts the speeds of the left and right rear wheels. Figure 11 As shown, the steering control method for this tricycle specifically includes the following steps:
[0137] S1101: Determine the adjustment coefficients for the left and right rear wheels based on the target steering direction, target steering angle, and the correspondence between the angle and the adjustment coefficient.
[0138] In this step, after the controller obtains the speeds of the left and right rear wheels, it can adjust the speeds of the left and right rear wheels to better match the current road conditions, so that the actual wheel speed can reach the determined wheel speed.
[0139] Based on the correspondence between angle and adjustment coefficient, the target adjustment coefficient corresponding to the target turning angle is determined. In the correspondence between angle and adjustment coefficient, the angle and adjustment coefficient are directly proportional, and the adjustment coefficient is a value greater than 1.
[0140] When the target turning direction is left, the right rear wheel experiences greater resistance, requiring an increase in wheel speed. Therefore, the adjustment coefficient for the left rear wheel is 1, and the adjustment coefficient for the right rear wheel is the target adjustment coefficient.
[0141] When the target turning direction is right, the left rear wheel experiences greater resistance, requiring an increase in wheel speed. Therefore, the adjustment coefficient for the right rear wheel is 1, and the adjustment coefficient for the left rear wheel is the target adjustment coefficient.
[0142] For example, when the angle is 10 degrees, the adjustment factor is 1.1; when the angle is 20 degrees, the adjustment factor is 1.3; and when the angle is 30 degrees, the adjustment factor is 1.4. This application does not limit the correspondence between angles and adjustment factors; these can be determined according to actual circumstances.
[0143] It should be noted that the controller can also update the adjustment coefficients of the left and right rear wheels based on the target steering direction and the acquired road surface adhesion coefficient. The target coefficient reduction amount corresponding to the acquired road surface adhesion coefficient is determined based on the correlation between the road surface adhesion coefficient and the coefficient reduction amount. In this correlation, the road surface adhesion coefficient and the coefficient reduction amount are directly proportional. This is because a higher road surface adhesion coefficient results in greater friction, more wear, a greater reduction in wheel speed, and thus a larger coefficient reduction.
[0144] When the target turning direction is left, the right rear wheel will wear more due to the vehicle's lateral slip. Therefore, the adjustment coefficient of the left rear wheel will not be updated. Instead, the difference between the adjustment coefficient of the right rear wheel and the amount of reduction in the coefficient will be used as the updated adjustment coefficient of the right rear wheel.
[0145] When the target turning direction is right, the left rear wheel will wear more due to the vehicle's lateral slip. Therefore, the adjustment coefficient of the right rear wheel will not be updated. Instead, the difference between the adjustment coefficient of the left rear wheel and the amount of reduction in the coefficient will be used as the updated adjustment coefficient of the left rear wheel.
[0146] For example, when the road surface adhesion coefficient is 0.6, the coefficient reduction is 0.1; when the road surface adhesion coefficient is 0.7, the coefficient reduction is 0.15; and when the road surface adhesion coefficient is 0.8, the coefficient reduction is 0.17. This application does not limit the correspondence between the road surface adhesion coefficient and the coefficient reduction; it can be determined according to the actual situation.
[0147] One method for obtaining the road surface adhesion coefficient is as follows: the controller stores the correspondence between location and road surface adhesion coefficient, and determines the corresponding road surface adhesion coefficient based on the current location. Another method is to install a camera on the road surface in the tricycle, and the controller inputs the road surface image captured by the camera into a trained machine learning model to obtain the road surface adhesion coefficient. This application does not limit the method for obtaining the road surface adhesion coefficient; it can be determined according to the actual situation.
[0148] S1102: Calculate the adjusted left rear wheel speed and right rear wheel speed based on the left rear wheel adjustment coefficient, right rear wheel adjustment coefficient, left rear wheel speed, and right rear wheel speed.
[0149] In this step, after the controller obtains the adjustment coefficients for the left and right rear wheels, it calculates the adjusted wheel speeds of the left and right rear wheels based on these coefficients, as well as the wheel speeds of the left and right rear wheels.
[0150] In other words, the adjusted left rear wheel speed is obtained by multiplying the left rear wheel adjustment factor by the left rear wheel speed. Similarly, the adjusted right rear wheel speed is obtained by multiplying the right rear wheel adjustment factor by the right rear wheel speed.
[0151] S1103: Control the rolling of the left and right rear wheels based on the adjusted left and right rear wheel speeds.
[0152] It should be noted that this step is similar to step S105 in Embodiment 1, and will not be described again here.
[0153] The tricycle steering control method provided in this embodiment improves the accuracy of the left and right rear wheel speeds by adjusting the left and right rear wheel speeds according to the target steering direction and target steering angle.
[0154] The following are embodiments of the apparatus described in this application, which can be used to execute the embodiments of the method described in this application. For details not disclosed in the apparatus embodiments of this application, please refer to the embodiments of the method described in this application.
[0155] Figure 12 This is a schematic diagram of an embodiment of the tricycle steering control device provided in this application; the device can be integrated into the controller in the above method embodiment, or it can be implemented through the controller in the above method embodiment. Figure 12 As shown, the tricycle steering control device 120 includes:
[0156] The acquisition module 121 is used to acquire the target steering direction, target steering angle, current vehicle speed, wheelbase, and track width.
[0157] Processing module 122 is used for:
[0158] The target speed is determined based on the target steering angle, the current vehicle speed, and the preset first vehicle speed threshold.
[0159] Determine the fixed wheel steering angle based on the wheelbase and track width;
[0160] Determine the left rear wheel speed and right rear wheel speed based on the target steering direction, fixed wheel steering angle, wheelbase, track width, target steering angle, and target vehicle speed;
[0161] The control module 123 is used to control the rolling of the left and right rear wheels according to the wheel speeds of the left and right rear wheels.
[0162] Furthermore, the processing module 122 is specifically used for:
[0163] If the target turning angle is 90 degrees, then the target speed is determined to be 0.
[0164] If the target turning angle is less than 90 degrees, the target speed is determined based on the current vehicle speed, the preset first vehicle speed threshold, and the preset second vehicle speed threshold. The preset second vehicle speed threshold is less than the preset first vehicle speed threshold.
[0165] Furthermore, the processing module 122 is specifically used for:
[0166] If the current vehicle speed is 0, then the target vehicle speed is determined to be the preset second vehicle speed threshold.
[0167] If the current vehicle speed is greater than 0 and less than or equal to the preset first vehicle speed threshold, then the target vehicle speed is determined to be the current vehicle speed.
[0168] If the current vehicle speed is greater than the preset first vehicle speed threshold, then the target vehicle speed is determined to be the preset first vehicle speed threshold.
[0169] Furthermore, the processing module 122 is specifically used for:
[0170] If the target steering angle is less than the fixed wheel steering angle, or if the target steering angle is greater than the fixed wheel steering angle but less than 90 degrees, then the left rear wheel speed and right rear wheel speed are determined based on the target steering direction, wheelbase, track width, target steering angle, and target vehicle speed.
[0171] If the target steering angle is equal to the fixed wheel steering angle, then determine the left rear wheel speed and the right rear wheel speed based on the target steering direction and the target vehicle speed.
[0172] If the target turning angle is 90 degrees, then the left rear wheel speed and right rear wheel speed are determined according to the target turning direction and the preset wheel speed. The preset wheel speed is greater than 0.
[0173] Furthermore, the processing module 122 is specifically used for:
[0174] Determine the ratio of the left rear wheel speed to the right rear wheel speed based on the target steering direction, wheelbase, track width, and target steering angle.
[0175] The sum of the left and right rear wheel speeds is set to twice the target vehicle speed.
[0176] Calculate the speed of the left rear wheel and the speed of the right rear wheel based on the wheel speed ratio and the sum of wheel speeds.
[0177] Furthermore, the processing module 122 is specifically used for:
[0178] If the target turning direction is left, then the speed of the left rear wheel is set to 0, and the speed of the right rear wheel is set to twice the target speed.
[0179] If the target turning direction is right, then the speed of the left rear wheel is determined to be twice the target speed, and the speed of the right rear wheel is 0.
[0180] Furthermore, the processing module 122 is specifically used for:
[0181] If the target turning direction is left, then the left rear wheel speed is determined to be the opposite of the preset wheel speed, and the right rear wheel speed is the preset wheel speed;
[0182] If the target turning direction is right, then the left rear wheel speed is set to the preset wheel speed, and the right rear wheel speed is set to the opposite of the preset wheel speed.
[0183] Furthermore, the processing module 122 is also used for:
[0184] If the front wheels are driven wheels with controllable steering, then the rotation of the front wheels is controlled according to the target steering direction and the target steering angle.
[0185] Furthermore, before controlling the left and right rear wheels to roll based on their speeds, the processing module 122 is also used for:
[0186] Based on the target steering direction, target steering angle, and the correspondence between angle and adjustment coefficient, determine the adjustment coefficients for the left and right rear wheels;
[0187] Calculate the adjusted left rear wheel speed and right rear wheel speed based on the left rear wheel adjustment coefficient, right rear wheel adjustment coefficient, left rear wheel speed, and right rear wheel speed;
[0188] The control module 123 is specifically used to control the rolling of the left and right rear wheels based on the adjusted left rear wheel speed and the adjusted right rear wheel speed.
[0189] The tricycle steering control device provided in this embodiment is used to execute the technical solution in any of the aforementioned method embodiments. Its implementation principle and technical effect are similar, and will not be described again here.
[0190] Figure 13 This is a schematic diagram of the structure of a controller provided in this application. Figure 13 As shown, the controller 130 includes:
[0191] Processor 131, memory 132, and communication interface 133;
[0192] Memory 132 is used to store executable instructions of processor 131;
[0193] The processor 131 is configured to execute the technical solution of the controller in any of the foregoing method embodiments by executing executable instructions.
[0194] Optionally, the memory 132 can be either standalone or integrated with the processor 131.
[0195] Optionally, when the memory 132 is a device independent of the processor 131, the controller 130 may further include:
[0196] Bus 134, memory 132 and communication interface 133 are connected to processor 131 through bus 134 and complete communication with each other. Communication interface 133 is used to communicate with other devices.
[0197] Optionally, the communication interface 133 can be implemented using a transceiver. The communication interface is used to enable communication between the database access device and other devices (e.g., clients, read-write databases, and read-only databases). The memory may include random access memory (RAM) and may also include non-volatile memory, such as at least one disk drive.
[0198] Bus 134 can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of representation, only one thick line is used in the diagram, but this does not indicate that there is only one bus or one type of bus.
[0199] The processors mentioned above can be general-purpose processors, including central processing units (CPUs), network processors (NPs), etc.; they can also be digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.
[0200] The controller is used to execute the technical solution of the controller in any of the aforementioned method embodiments. Its implementation principle and technical effect are similar, and will not be described again here.
[0201] This application also provides a three-wheeled vehicle, which includes a controller, a front wheel, a left rear wheel, and a right rear wheel.
[0202] The front wheel of the tricycle is the driven wheel, while the left and right rear wheels are independently driven wheels.
[0203] The controller is used to execute the technical solutions in any of the foregoing method embodiments. Its implementation principle and technical effect are similar, and will not be repeated here.
[0204] This application also provides a readable storage medium storing a computer program thereon, which, when executed by a processor, implements the technical solutions provided in any of the foregoing method embodiments.
[0205] This application also provides a computer program product, including a computer program, which, when executed by a processor, is used to implement the technical solutions provided in any of the foregoing method embodiments.
[0206] Those skilled in the art will understand that all or part of the steps of the above-described method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.
[0207] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.
Claims
1. A steering control method for a tricycle, characterized in that, A controller applied to a tricycle, wherein the front wheel of the tricycle is a driven wheel, and the left and right rear wheels of the tricycle are independently driven drive wheels, the method comprising: Obtain the target steering direction, target steering angle, current vehicle speed, wheelbase, and track width; The target vehicle speed is determined based on the target steering angle, the current vehicle speed, and a preset first vehicle speed threshold. The fixed wheel steering angle is determined based on the wheelbase and the track width. If the target steering angle is less than the fixed wheel steering angle, or if the target steering angle is greater than the fixed wheel steering angle but less than 90 degrees, then the left rear wheel speed and the right rear wheel speed are determined based on the target steering direction, the wheelbase, the track width, the target steering angle, and the target vehicle speed. If the target steering angle is equal to the fixed wheel steering angle, then the left rear wheel speed and the right rear wheel speed are determined according to the target steering direction and the target vehicle speed. If the target steering angle is equal to 90 degrees, then the left rear wheel speed and the right rear wheel speed are determined according to the target steering direction and the preset wheel speed, wherein the preset wheel speed is greater than 0. The left and right rear wheels are controlled to roll according to the speed of the left and right rear wheels.
2. The method according to claim 1, characterized in that, Determining the target vehicle speed based on the target steering angle, the current vehicle speed, and a preset first vehicle speed threshold includes: If the target turning angle is 90 degrees, then the target vehicle speed is determined to be 0. If the target steering angle is less than 90 degrees, the target vehicle speed is determined based on the current vehicle speed, the preset first vehicle speed threshold, and the preset second vehicle speed threshold, wherein the preset second vehicle speed threshold is less than the preset first vehicle speed threshold.
3. The method according to claim 2, characterized in that, Determining the target vehicle speed based on the current vehicle speed, the preset first vehicle speed threshold, and the preset second vehicle speed threshold includes: If the current vehicle speed is equal to 0, then the target vehicle speed is determined to be the preset second vehicle speed threshold. If the current vehicle speed is greater than 0 and less than or equal to the preset first vehicle speed threshold, then the target vehicle speed is determined to be the current vehicle speed; If the current vehicle speed is greater than the preset first vehicle speed threshold, then the target vehicle speed is determined to be the preset first vehicle speed threshold.
4. The method according to claim 1, characterized in that, The step of determining the left rear wheel speed and the right rear wheel speed based on the target steering direction, the wheelbase, the track width, the target steering angle, and the target vehicle speed includes: Based on the target steering direction, the wheelbase, the track width, and the target steering angle, determine the wheel speed ratio between the left rear wheel speed and the right rear wheel speed; The sum of the left rear wheel speed and the right rear wheel speed is taken as twice the target vehicle speed. The wheel speeds of the left and right rear wheels are calculated based on the wheel speed ratio and the sum of the wheel speeds.
5. The method according to claim 1, characterized in that, Determining the left rear wheel speed and the right rear wheel speed based on the target steering direction and the target vehicle speed includes: If the target turning direction is left, then the speed of the left rear wheel is determined to be 0, and the speed of the right rear wheel is twice the target vehicle speed; If the target turning direction is right, then the speed of the left rear wheel is determined to be twice the target vehicle speed, and the speed of the right rear wheel is 0.
6. The method according to claim 1, characterized in that, The step of determining the left rear wheel speed and the right rear wheel speed based on the target steering direction and the preset wheel speed includes: If the target turning direction is left, then the left rear wheel speed is determined to be the opposite of the preset wheel speed, and the right rear wheel speed is the preset wheel speed; If the target turning direction is right, then the left rear wheel speed is determined to be the preset wheel speed, and the right rear wheel speed is the opposite of the preset wheel speed.
7. The method according to any one of claims 1 to 6, characterized in that, The method further includes: If the front wheel is a driven wheel with controllable steering, then the rotation of the front wheel is controlled according to the target steering direction and the target steering angle.
8. The method according to any one of claims 1 to 6, characterized in that, Before controlling the rotation of the left and right rear wheels based on the left and right rear wheel speeds, the method further includes: Based on the target steering direction, the target steering angle, and the correspondence between the angle and the adjustment coefficient, determine the adjustment coefficients for the left rear wheel and the right rear wheel; Calculate the adjusted left rear wheel speed and the adjusted right rear wheel speed based on the left rear wheel adjustment coefficient, the right rear wheel adjustment coefficient, the left rear wheel speed, and the right rear wheel speed; The step of controlling the rotation of the left and right rear wheels based on the speeds of the left and right rear wheels includes: The left and right rear wheels are controlled to roll according to the adjusted left and right rear wheel speeds.
9. A steering control device for a tricycle, characterized in that, The three-wheeled vehicle steering control method according to any one of claims 1 to 8 is adopted.
10. A controller, characterized in that, include: Processor, memory, communication interface; The memory is used to store the executable instructions of the processor; The processor is configured to execute the tricycle steering control method according to any one of claims 1 to 8 by executing the executable instructions.
11. A three-wheeled vehicle, characterized in that, include: Controller, front wheel, left rear wheel, and right rear wheel; The front wheel of the tricycle is a driven wheel, and the left and right rear wheels of the tricycle are independently driven drive wheels. The controller is used to execute the tricycle steering control method according to any one of claims 1 to 8.
12. A readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the tricycle steering control method according to any one of claims 1 to 8.
13. A computer program product, characterized in that, Includes a computer program, which, when executed by a processor, is used to implement the tricycle steering control method according to any one of claims 1 to 8.