Steering control method and equipment for distributed wheel set independent drive steering drive-by-wire chassis

Abstract

The invention discloses a steering control method and device for a distributed wheel set independent drive steering drive-by-wire chassis, and the method comprises the steps: carrying out the real-time decision according to a path tracking condition, and obtaining a vehicle motion demand signal; determining a target deflection value of each wheel set in combination with a vehicle kinematics relationship; determining the differential required rotating speed of each wheel set according to the deflection target value and the actual feedback value of each wheel set, and coordinately distributing the differential required rotating speed to each driving wheel; according to the vehicle speed demand signal and the steering demand signal, the basic rotating speed of each wheel (group) after entering the target steady-state steering is solved in real time; the differential required rotating speed and the basic required rotating speed of each wheel set are superposed to serve as the target rotating speed of each wheel; and the motor driving control system controls the output torque of each motor according to the target rotating speed and the actual rotating speed of each driving wheel. The maneuverability and flexibility of the special vehicle are effectively improved, the response speed of the whole vehicle is increased, and meanwhile more ideal pose control is achieved, so that the working efficiency is effectively improved, the burden of workers is reduced, and the emission level is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of steer-by-wire for articulated steering vehicles, and particularly relates to a steering control method and device for a distributed wheel group independently-driven and steered steer-by-wire chassis. Background Art

[0002] As an important transportation machinery, multi-axle special vehicles have good load-bearing capacity and adaptability, and are widely used in military, aerospace and other fields. Limited by the large body volume and working load of multi-axle special vehicles, their maneuverability and controllability are usually widely concerned.

[0003] At present, the low-carbon and intelligent development of special vehicles has become an important development direction. Among them, due to the large self-weight and volume of multi-axle special vehicles, the design of their drive configuration and steering method directly affects the vehicle's maneuverability, controllability and even energy consumption economy. However, the current traditional multi-axle special vehicles generally have the following deficiencies: First, in terms of the steering method, vehicles using traditional wheel steering methods have obvious deficiencies in maneuverability. In order to make the vehicle accurately execute the path tracking requirement, the driver may need to repeatedly adjust the vehicle posture. Therefore, the operation efficiency in some special scenario working conditions is not good, and the design of the steering mechanism is relatively complex; Second, in terms of the drive configuration, traditional multi-axle special vehicles widely adopt hybrid drive and hydraulic drive configurations, which not only have a complex transmission system design, but also have poor energy consumption economy, and do not conform to the green development trend; Third, although multi-axle special vehicles adopting distributed electric drive configuration combined with differential steering method can effectively overcome the above two defects, it also puts forward higher requirements for the overall vehicle control level. For example, if the driving wheels cannot achieve an effective synergistic effect, it may lead to serious tire wear and tear and a sharp increase in energy consumption, as well as dangerous situations such as tracking failure and even vehicle side slip. For example, adopting the distributed Mecanum wheel steering method usually poses challenges in vehicle lateral stability control. Nowadays, with the continuous iteration of electronic and electrical control technologies and the development of vehicle steer-by-wire chassis technology, combined with the layout advantages of the domestic electric drive equipment industry, it provides new possibilities for solving the controllability and energy consumption problems of multi-axle special vehicles.

[0004] Therefore, in view of the problems of poor flexibility and controllability, low operation efficiency and poor energy consumption economy of traditional multi-axle special vehicles, a steering control method, device, equipment and storage medium for a distributed wheel group independently-driven and steered steer-by-wire chassis are proposed. Summary of the Invention

[0005] Based on the distributed wheel group independent differential electric drive configuration and steer-by-wire chassis technology, the present invention makes full use of the fast, accurate response and low emission characteristics of direct motor drive to solve the problems of poor maneuverability and energy consumption economy, poor pose control accuracy and tracking performance of traditional multi-axle special vehicles.

[0006] The first object of the present invention is to provide a steering control method for a distributed wheel group independently driven and steered by wire chassis, including: According to the path tracking situation, obtain the motion demand signals of a multi-wheel group distributed electric drive configuration vehicle in real time; wherein, the motion demand signals include steering demand signals and vehicle speed demand signals; Based on the vehicle kinematic relationship and the steering demand signal, determine the deflection target values of each wheel group of the multi-wheel group distributed electric drive configuration vehicle; According to the deflection target values and actual feedback values of each wheel group of the multi-wheel group distributed electric drive configuration vehicle, determine the differential speed demand of each wheel group, and optimize and allocate the drive wheels assigned to each wheel group in real time according to the motion state feedback of the whole vehicle as the differential speed target speed; Based on the steering demand signal and vehicle speed demand signal, determine the basic target speed of each wheel group of the multi-wheel group distributed electric drive configuration vehicle after entering the target steady-state steering; Based on the basic target speed and differential speed target speed of the drive wheels in each wheel group, regulate the drive motors of each drive wheel to achieve the steering control of the distributed wheel group independently driven and steered by wire chassis.

[0007] Further, based on the vehicle kinematic relationship and the steering demand signal, determining the deflection target values of each wheel group of the multi-wheel group distributed electric drive configuration vehicle includes: Analyze the steering demand signal and vehicle speed demand signal in the motion demand signal, and determine the target deflection angle of each wheel group according to the preset steering mode demand by considering the vehicle kinematic parameter characteristics; According to the first-order quantity of the steering demand signal collected by the differential link, determine the target angular velocity of the deflection of each wheel group.

[0008] Further, according to the position of the target steering center, the motion modes of the multi-wheel group distributed electric drive configuration vehicle are divided into long-side steering, short-side steering, self-rotation and translation; according to the actual requirements, the motion modes of the multi-wheel group distributed electric drive configuration vehicle are divided into normal steering, swing steering, in-situ steering, lateral translation, crab walking and other arbitrary positions.

[0009] Further, determining the differential speed demand of each wheel group according to the deflection target quantity and actual feedback value of each wheel group of the multi-wheel group distributed electric drive configuration vehicle, and optimizing and allocating the drive wheels assigned to each wheel group in real time according to the motion state feedback of the whole vehicle as the differential speed target speed includes: Based on the target deflection angle, target angular velocity of the deflection of each wheel group and the real vehicle feedback value, perform closed-loop control on the deflection actions of each wheel group respectively to determine the differential speed demand of each wheel group; Collect the motion state feedback of the whole vehicle in real time, apply the vehicle lateral stability control optimization algorithm, and reasonably allocate the differential speed demand of each wheel group to the drive wheels in each wheel group as the differential speed demand speed of the drive wheels.

[0010] Further, based on the steering demand signal and the vehicle speed demand signal, determine the basic target speeds of each wheel group of the multi-wheel group distributed electric drive configuration vehicle after entering the target steady-state steering, including: Analyze the vehicle speed demand signal, and in combination with the steering demand signal and the vehicle kinematic relationship, calculate the required speeds of the drive wheels in each wheel group as the basic target speeds; In combination with the real-time feedback of the wheel group deflection state, further optimize the intervention timing of the basic target speed.

[0011] Further, each wheel group of the multi-wheel group distributed electric drive configuration vehicle includes two drive wheels, and each drive wheel is equipped with an independent drive motor and an encoder to

[0012] Further, based on the basic target speed and the differential target speed of the drive wheels in each wheel group, regulate the drive motors of each drive wheel to achieve the steering control of the distributed wheel group independent drive steering by wire chassis, including: Superimpose the basic target speed and the differential target speed of the drive wheels in each wheel group as the target speed of the drive wheels in the corresponding wheel group, and input it into the motor drive control system of the multi-wheel group distributed electric drive configuration vehicle; The motor drive control system adjusts and controls the output torque of the drive motor of each drive wheel according to the target speed and the actual speed of the drive wheels in each wheel group to achieve the steering control of the distributed wheel group independent drive steering by wire chassis.

[0013] The second object of the present invention is to provide a steering control device for a distributed wheel group independent drive steering by wire chassis, including: An input module for obtaining the motion demand signal of the multi-wheel group distributed electric drive configuration vehicle in real time according to the path tracking situation; wherein, the motion demand signal includes a steering demand signal and a vehicle speed demand signal; A wheel group deflection target analysis module for determining the deflection target values of each wheel group of the multi-wheel group distributed electric drive configuration vehicle based on the steering demand signal according to the vehicle kinematic relationship; A wheel group deflection following control module for determining the differential demand of each wheel group according to the deflection target value and the actual feedback value of each wheel group of the multi-wheel group distributed electric drive configuration vehicle, and in real time optimizing and allocating the drive wheels for each wheel group according to the motion state feedback of the whole vehicle as the differential target speed; A steering control module is configured to regulate the drive motors of each drive wheel based on the basic target rotational speed and the differential target rotational speed of the drive wheels in each wheel group, so as to achieve the steering control of a steer-by-wire chassis with distributed wheel groups independently driven.

[0014] The third object of the present invention is to provide an electronic device, including: at least one processor; and a memory communicatively connected to the at least one processor; wherein, the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the steps in the method described in the foregoing technical solution.

[0015] The fourth object of the present invention is to provide a non-transitory computer-readable storage medium storing computer instructions, wherein the computer instructions are used to cause a computer to execute the steps in the method described in the foregoing technical solution.

[0016] Compared with the prior art, the advantages of the present invention are as follows: By designing a targeted steering control method, the present invention can give full play to the structural advantages of the steer-by-wire chassis special vehicle with a distributed wheel group independent electric drive configuration. By utilizing the fast, precise response and high-efficiency characteristics of direct motor drive, it is not only beneficial to solve the problem of high requirements for vehicle control of distributed wheel group independent drive special vehicles, but also combined with the supply advantages of the domestic electric drive equipment industry, it can significantly reduce the emission level, meeting the development trend of intelligent equipment being green and environmentally friendly; The steering control method designed by the present invention is applicable to special vehicles equipped with any number of wheel groups and has universality; it can perform real-time cooperative closed-loop regulation on each wheel (group) respectively according to the upper-layer motion requirements, enabling the distributed wheel group steer-by-wire electric drive special vehicle to achieve six driving actions such as crab walking, swing turning, and in-situ rotation, which are difficult for traditional multi-axle special vehicles to complete, significantly improving the maneuverability and flexibility of the vehicle and being beneficial to improving the operation efficiency of special vehicles; By designing wheel group deflection target parsing, deflection following control, and basic target rotational speed calculation, the present invention realizes a hierarchical coordinated control strategy for the target rotational speeds of each drive wheel, and takes into account the change rate of the upper-layer steering demand signal. While ensuring that the target rotational speeds of each drive wheel group match the vehicle motion requirements, it improves the vehicle tracking rapidity and accuracy to achieve more ideal path tracking and pose control requirements, which is beneficial to reducing the burden on the staff; The steering control method designed by the present invention can combine the deflection states of each wheel group and the real-time feedback of the vehicle motion state, and further compensate and optimize the output parameters of each part by applying various control algorithms, having a broad control development space to ensure the driving stability of the vehicle under various working conditions, improving the vehicle control efficiency while reducing tire side wear and unnecessary power loss, and further improving the vehicle energy consumption economy. Description of the Drawings

[0017] Figure 1 Schematic flow chart of a steering control method for a distributed wheel set independently driven and steered by wire chassis provided by the present invention; Figure 2 Logical schematic diagram of a steering control method for a distributed wheel set independently driven and steered by wire chassis provided by the present invention; Figure 3 Schematic diagram of the corresponding relationship between the wheel set mechanism, the target steering center and the steering mode in the steering control method for a distributed wheel set independently driven and steered by wire chassis provided by the present invention; Figure 4 Definition diagram of vehicle motion parameters in the steering control method for a distributed wheel set independently driven and steered by wire chassis provided by the present invention; Figure 5 Schematic diagram of the motion mode in the steering control method for a distributed wheel set independently driven and steered by wire chassis provided by the present invention; Figure 6 Schematic structural diagram of a steering control device for a distributed wheel set independently driven and steered by wire chassis of the present invention.

[0018] Figure 7 Schematic structural diagram of a non-transitory computer-readable storage medium storing computer instructions provided by the present invention. Detailed implementation manners

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for use in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0020] As Figure 1 and Figure 2 shown, the present invention provides a steering control method for a distributed wheel set independently driven and steered by wire chassis, including: S110: According to the path tracking situation, obtain the motion demand signals of a multi-wheel set distributed electric drive configuration vehicle in real time; wherein, the motion demand signals include steering demand signals and vehicle speed demand signals.

[0021] The steering control method of the present invention is applicable to special vehicles with a multi-wheel set distributed electric drive configuration (applicable to special vehicles equipped with any number of wheel sets). In this embodiment, a four-axle special vehicle is taken as an example for introduction.

[0022] In a specific embodiment, as Figure 3As shown in the figure, a single wheel set of a multi-wheel set distributed electric drive configuration vehicle consists of two drive wheels. Each wheel set can be independently controlled for driving and differential steering, and each drive wheel is equipped with a motor independently controlled for driving. A single drive wheel set consists of two drive wheels, which are respectively equipped with independent drive motors and encoders, and can real-time feedback the wheel speeds of each drive wheel; when a speed difference is formed between the two drive wheels, the wheel set can perform differential deflection around the central deflection axis, and at the same time, an angular displacement sensor is equipped at the deflection axis, which can real-time feedback the deflection state of each wheel set.

[0023] Each wheel set of the multi-wheel set distributed electric drive configuration vehicle can be independently and coordinately controlled, enabling the whole vehicle to more quickly and accurately execute the path tracking intention of the driver (autopilot unit), and achieving more ideal pose control. Compared with the traditional multi-axle special vehicle configuration, there is no need to additionally design complex steering mechanisms and transmission mechanisms, which is beneficial to reducing energy consumption and emission levels; at the same time, the full-wire control technology is adopted to give full play to the advantages of the high flexibility of the distributed multi-wheel set electric drive configuration, and a variety of advanced modern control theories can be applied, with broad development space; by coordinately controlling each wheel set, in addition to normal straight driving and steering actions, this kind of vehicle can also perform actions that traditional multi-axle vehicles cannot execute, such as crab walking, self-rotation, and swing rotation, effectively improving the maneuverability and flexibility; combined with the high-speed and high-precision response characteristics of the motor drive, it can form a favorable cooperation with the distributed multi-wheel set configuration, achieve more ideal path tracking and pose control, reduce the burden on the staff, and effectively improve the operation efficiency.

[0024] Specifically, this step includes the following steps: S111: Analyze the steering demand signal and vehicle speed demand signal in the motion demand signal, and determine the target deflection angle of each wheel set according to the preset steering mode demand by considering the kinematic parameter characteristics of the whole vehicle.

[0025] S112: To enhance the timeliness and accuracy of vehicle path tracking, reduce high-frequency jitter and steady-state error, collect the first-order quantity of the steering demand signal in combination with the differential link, and determine the target angular velocity of the deflection angle of each wheel set.

[0026] In this embodiment, the motion demand signal is used as the input signal, which comes from the upper-layer path tracking decision control link and can face the needs of manual driving or autopilot. The motion demand signal includes two parts: the steering demand signal and the vehicle speed demand signal. Based on the real-time analysis of the motion demand signal and combined with the feedback value of the deflection situation of each wheel set for closed-loop control, and further real-time optimization based on the feedback value of the vehicle body motion state, finally the target rotational speeds of each drive wheel are output.

[0027] In this embodiment, a four-axle special vehicle is taken as an example, with a total of 8 wheel sets and 16 drive wheels, that is i = 1~16, j= 1 to 8; perform closed-loop coordinated control on the specific actions of each drive wheel (group), enabling the special vehicle to complete faster and more accurate path tracking and pose control, and taking into account the driving stability and energy consumption economy under various working conditions, providing a solution to the problem of high requirements for vehicle control of distributed differential wheel group electric drive special vehicles.

[0028] S120: According to the vehicle kinematic relationship, based on the steering demand signal, determine the deflection target values of each wheel group of the multi-wheel group distributed electric drive configuration vehicle.

[0029] This step includes: S121: Based on the target deflection angle, target angular velocity of each wheel group, and the actual vehicle feedback value, perform closed-loop control on the deflection actions of each wheel group respectively, and determine the differential demand of each wheel group.

[0030] S122: To fully coordinate and optimize the drive wheel adhesion rate of each wheel group, ensure the dynamic stability and even traceability of the vehicle's steering, collect the vehicle's motion state feedback in real time, apply the vehicle's lateral stability control optimization algorithm, and reasonably distribute the differential demand of each wheel group to the drive wheels in each wheel group as the differential demand rotational speed of the drive wheels.

[0031] By analyzing the motion demand signal input from the driver or the autonomous driving unit, considering the characteristics of the vehicle kinematic parameters, and parsing the target deflection angle of each wheel group in real time according to the requirements of different steering modes; according to the position of the target steering center, it can be generally classified into four major categories of motion modes: long-side steering, short-side steering, self-rotation, and translation, and according to actual needs, it can be further subdivided into six motion modes: normal steering, swing turning, in-place turning, lateral movement, crab walking, and other arbitrary positions; at the same time, to enhance the timeliness and accuracy of the vehicle's path tracking, reduce high-frequency jitter and steady-state error, and better execute the upper-layer steering demand, this module also collects the first-order quantity of the steering demand signal in combination with the differential link, and parses the target angular velocity of the deflection angle of each wheel group in real time.

[0032] Specifically, for the convenience of description, define each geometric parameter and motion parameter as Figure 4 shown as is the target steering center is the angle relative to the lateral horizontal line direction of the vehicle body is the turning radius of the vehicle body center is the turning radius of each wheel group center is the actual deflection angle of each wheel group (relative to the vehicle body horizontal direction) is the longitudinal vehicle speed of the vehicle body center is the lateral vehicle speed of the vehicle body center is the yaw angular velocity of the vehicle body is the vehicle body center speed and are the vehicle body geometric parameters is the wheelbase between two drive wheels within the wheel set.

[0033] For the four major categories of different motion modes of special vehicles, different motion demand signals need to be input, and this process is decided in real time by the upper-level path tracking link according to road conditions. According to actual requirements, in addition to normal straight-line driving, the four major categories of different motion modes can be further divided into six motion modes: lateral movement, crab movement, normal steering, swing rotation, in-situ rotation, and any other steering center position, as Figure 5 shown. Among them, lateral movement and crab movement can be classified into the translation category, normal steering can be classified into the long-side steering category, swing rotation can be classified into the short-side steering category, and in-situ rotation can be classified into the self-rotation category. In short, all the steering actions that the special vehicle can perform can be summarized into the above four major motion modes. For systematic description, the four major motion modes of long-side steering, short-side steering, self-rotation, and translation are introduced separately here.

[0034] For the long-side steering category, the input motion demand signal is ( and are the steering demand signal and vehicle speed demand signal respectively, the same below): That is, a given target steering center position and a longitudinal target vehicle speed are given. Taking the situation shown in Figure 4 as an example, according to the vehicle kinematic relationship, the steering radius at the center of each wheel set can be calculated by the following formula: Then the deflection angle of each wheel set is analyzed as follows: For the short-side steering category, the input motion demand signal is: That is, a given target steering center position and a lateral target vehicle speed are given. Taking the situation shown in Figure 4 as an example, the analysis process of the swing angle of each wheel set is the same as above, and only the and body geometric parameters need to be simply replaced, which will not be elaborated here.

[0035] For the self-rotation category, the input motion demand signal is: That is, a given rotational angular velocity is given. Taking the situation shown in Figure 4 (in-situ rotation) as an example, since the rotation center is located at the center of the vehicle body, the swing angle of each wheel set is a fixed value: For the translation mode, the input motion demand signal is as follows: That is, directly specify the deflection angles of each wheel set and the longitudinal target vehicle speed, so as to make the swing angles of each wheel set match the vehicle body motion demand relationship.

[0036] S130: Determine the differential demand of each wheel set according to the deflection target value and the actual feedback value of each wheel set of the multi-wheel set distributed electric drive configuration vehicle, and optimize and allocate the drive wheels assigned to each wheel set in real time according to the motion state feedback of the whole vehicle as the differential target rotational speed.

[0037] This step specifically includes: S131: Carry out closed-loop control on the deflection actions of each wheel set respectively based on the target deflection angle, target angular velocity of deflection of each wheel set and the real vehicle feedback value, and determine the differential demand of each wheel set.

[0038] S132: Real-time collect the motion state feedback of the whole vehicle, apply the optimization algorithm of the whole vehicle lateral stability control, and reasonably allocate the differential demand of each wheel set to the drive wheels in each wheel set as the differential demand rotational speed of the drive wheels.

[0039] In the embodiment of the present invention, a proportional-integral-derivative closed-loop controller is set up to carry out closed-loop control on the deflection actions of each wheel set respectively according to the deflection target value (deflection angle and angular velocity of deflection) of each wheel set and the real vehicle feedback value, and determine the differential demand of each wheel set; at the same time, in order to fully coordinate and optimize the adhesion rate of each drive wheel and ensure the dynamic stability and even traceability of the whole vehicle steering, the differential demand of each wheel set can be reasonably allocated to the two side drive wheels (specifically, it needs to be further designed and calibrated according to the actual working condition requirements) by real-time collecting the motion state feedback of the whole vehicle and applying optimization algorithms such as the whole vehicle lateral stability control as the differential demand rotational speed of each drive wheel.

[0040] Specifically, the wheel set deflection target value, that is, the target deflection angle and target angular velocity of deflection of each wheel set, come from the real-time calculation of the wheel set deflection target analysis module, and the actual values of the deflection states of each wheel set, that is, the deflection angle and angular velocity of deflection, come from the real-time feedback of the angular displacement sensors equipped on each wheel set. The two are used for the closed-loop following control of the wheel set deflection, so that the whole vehicle can quickly and accurately execute the path tracking and pose control requirements. Briefly introduce the design of the wheel set deflection following controller and define the state deviation: Among them, and are the target deflection angle and target angular velocity of deflection respectively, and are the actual deflection angle and angular velocity of deflection respectively, and are the proportionality coefficients, which can be used to adjust the respective emphasis degrees for the deflection angle and angular velocity of deflection.

[0041] Define as the differential speed demand for each wheel set (total) (j = 1 to 8, representing 8 wheel sets): Among them and are the differential speed demand rotational speeds of the two drive wheels on a single wheel set (i = 1 to 16, representing 16 drive wheels) respectively. According to the proportional - derivative - integral controller design, the differential speed demand for the deflection of each wheel set (total) is expressed as: Among them, 、 and are the proportional, integral, and differential term coefficients respectively, and their values need to be adjusted according to the actual situation.

[0042] Furthermore, the differential speed demand for the deflection of a single wheel set (total) finally needs to be further distributed to the two drive wheels on both sides. Due to the particularity and complexity of multi - wheel - set special vehicles, the requirements for vehicle control are relatively high. Therefore, to ensure the coordination of the movement of each wheel set and the energy consumption economy of the whole vehicle, the real - time motion state feedback of the whole vehicle can be collected through the vehicle body IMU sensor, etc., and means such as slip ratio distribution control, vehicle lateral stability control, and other optimization compensation algorithms can be combined to coordinately distribute the differential speed target rotational speeds of each drive wheel, so as to further enhance various performance indicators such as the driving stability, tracking performance, and energy consumption economy of the whole vehicle, and further improve the operation efficiency.

[0043] The distribution form of the differential speed target rotational speeds of the two drive wheels on both sides of a single wheel set is as follows: Among them, is the distribution coefficient, which can be further designed and developed, but the two target rotational speeds must always meet the definition of "differential speed demand for a single wheel set (total)" above.

[0044] S140: According to the steering demand signal and the vehicle speed demand signal, determine the basic target rotational speeds of each wheel set of the multi - wheel - set distributed electric drive configuration vehicle after entering the target steady - state steering.

[0045] This step includes: S141: Analyze the vehicle speed demand signal, and combine the steering demand signal and the vehicle kinematic relationship to calculate the demand rotational speed of the drive wheels in each wheel set as the basic target rotational speed.

[0046] S142: Further optimize the intervention timing of the basic target rotational speed in combination with the real - time feedback of the wheel set deflection state.

[0047] In a specific embodiment, speed demand signals such as throttle and brake input by the upper-layer path tracking link are parsed, and the required rotational speeds of each drive wheel are calculated in real time in combination with the steering demand signal and vehicle kinematic relationship as the basic target rotational speeds. In addition, to avoid tire side slip and excessive uneven wear and cause additional interference to the control in the initial stage of steering, and improve the driving stability of the whole vehicle, the basic target rotational speed can be delayed and intervened in real time in combination with the deflection state of the wheel set, and can be calibrated according to the actual working condition requirements.

[0048] Based on the wheel motion relationship in the four motion modes of normal steering, swing turning, self-rotation and crab walking and the motion demand signal input by the upper layer, the basic target rotational speed of each drive wheel is determined.

[0049] For the normal steering mode, the turning center position of the vehicle body is given , turning radius and longitudinal target vehicle speed After that, the yaw angular velocity and the centroid velocity of the whole vehicle can be calculated respectively by the following formulas: Then the basic target rotational speed of each drive wheel (i = 1~16) can be expressed as (G is the wheelbase of the wheel set): For the swing turning mode, the turning center position of the vehicle body is given , turning radius and lateral target vehicle speed After that, the yaw angular velocity and the centroid velocity of the whole vehicle can be calculated respectively by the following formulas: The calculation methods of the basic target rotational speed of each drive wheel in the normal steering mode, swing turning mode and self-rotation mode are the same.

[0050] For the crab walking mode, given the target deflection angle of each wheel set (j = 1~8) and longitudinal target vehicle speed After that, the basic target rotational speed of each drive wheel (i = 1~16) can be expressed as: S150: Based on the basic target rotational speed and differential target rotational speed of the drive wheels in each wheel set, the drive motors of each drive wheel are regulated to achieve the steering control of the distributed wheel set independent drive and steer-by-wire chassis.

[0051] According to the control strategy design, the final target rotational speed of each drive wheel can be expressed as the differential target rotational speed and the base target speed superposition: Then the target speed of each motor finally output to the motor drive control system is (I is the reduction ratio): Since the base target speed is the required speed after entering the steady-state steering, considering the complexity of the entire steering dynamic process of a multi-axle vehicle, in order to avoid causing additional interference to the wheel group deflection control stage in the initial stage of steering and affecting driving stability and energy consumption economy, the intervention of the base target speed based on the feedback of the deflection state of each wheel group and the motion state of the whole vehicle can be further optimized in the time domain.

[0052] As Figure 6 shown, the present invention proposes a steering control device 600 for a distributed wheel group independent drive steering by wire chassis, including: An input module 610, configured to obtain the motion demand signal of a multi-wheel group distributed electric drive configuration vehicle in real time according to the path tracking situation; wherein, the motion demand signal includes a steering demand signal and a vehicle speed demand signal; A wheel group deflection target analysis module 620, configured to determine the deflection target value of each wheel group of a multi-wheel group distributed electric drive configuration vehicle based on the steering demand signal according to the vehicle kinematic relationship; A wheel group deflection following control module 630, configured to determine the differential demand of each wheel group according to the deflection target value and the actual feedback value of each wheel group of a multi-wheel group distributed electric drive configuration vehicle, and optimize and allocate the drive wheels to each wheel group in real time according to the motion state feedback of the whole vehicle as the differential target speed; A wheel group base target speed calculation module 640, configured to determine the base target speed of each wheel group of a multi-wheel group distributed electric drive configuration vehicle after entering the target steady-state steering according to the steering demand signal and the vehicle speed demand signal; A steering control module 650, configured to regulate the drive motor of each drive wheel based on the base target speed and the differential target speed of the drive wheel in each wheel group, so as to realize the steering control of the distributed wheel group independent drive steering by wire chassis.

[0053] To implement the embodiment, the present invention also proposes an electronic device, including: at least one processor; and a memory communicatively connected to at least one processor; wherein, the memory stores instructions executable by at least one processor, and the instructions are executed by at least one processor so that at least one processor can execute the steps in the foregoing method.

[0054] As Figure 7As shown, the non-transitory computer-readable storage medium includes a memory 810 for instructions, an interface 830, and the instructions can be executed by a processor 820 to complete the method. Optionally, the storage medium can be a non-transitory computer-readable storage medium. For example, the non-transitory computer-readable storage medium can be a ROM, a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, and an optical data storage device, etc.

[0055] To implement the embodiments, the present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the method as in the embodiments of the present invention is implemented.

[0056] In the description of this specification, the descriptions with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection 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 are not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0057] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" can explicitly or implicitly include at least one of such features. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0058] Any process or method description in the flowchart or described in other ways herein can be understood to represent a module, segment, or part of the code including one or more executable instructions for implementing a customized logic function or process. The scope of the preferred embodiments of the present invention includes additional implementations, where the functions can be executed in a substantially simultaneous manner or in a reverse order according to the involved functions, rather than in the order shown or discussed, which should be understood by those skilled in the art to which the embodiments of the present invention pertain.

[0059] Logic and / or steps represented in a flowchart or otherwise described herein, for example, can be considered as a definite sequence list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or used in conjunction with these instruction execution systems, apparatus, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in conjunction with an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection portion having one or more wirings (electronic device), a portable computer diskette (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpretation, or other suitable processing as necessary, and then stored in a computer memory.

[0060] It should be understood that various parts of the present invention can be implemented by hardware, software, firmware, or a combination thereof. In the described embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or a combination of the following techniques well known in the art can be used: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application-specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), etc.

[0061] Those of ordinary skill in the art of this technology can understand that all or part of the steps carried by the method of the described embodiments can be completed by instructing relevant hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiments.

[0062] In addition, each functional unit in various embodiments of the present invention may be integrated into one processing module, may exist physically alone for each unit, or two or more units may be integrated into one module. The integrated module may be implemented in the form of hardware or in the form of a software functional module. When the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0063] The aforementioned storage medium may be a read-only memory, a magnetic disk, an optical disc, etc. Although the embodiments of the present invention have been shown and described above, it can be understood that the embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the embodiments within the scope of the present invention.

[0064] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A steering control method for a distributed wheel set independent drive steer-by-wire chassis, characterized in that Including: Obtain the motion demand signals of a multi-wheel-group distributed electric drive configuration vehicle in real time according to the path tracking situation; wherein, the motion demand signals include steering demand signals and vehicle speed demand signals; Based on the vehicle kinematic relationship and the steering demand signal, determine the deflection target values of each wheel group of the multi-wheel-group distributed electric drive configuration vehicle; According to the deflection target values and actual feedback values of each wheel group of the multi-wheel-group distributed electric drive configuration vehicle, determine the differential demand of each wheel group, and optimize and allocate the drive wheels assigned to each wheel group in real time according to the motion state feedback of the whole vehicle as the differential target speed; Based on the steering demand signal and the vehicle speed demand signal, determine the basic target speed of each wheel group of the multi-wheel-group distributed electric drive configuration vehicle after entering the target steady-state steering; Based on the basic target speed and the differential target speed of the drive wheels in each wheel group, regulate the drive motors of each drive wheel to achieve the steering control of the distributed wheel group independent drive steering-by-wire chassis.

2. The steering control method of a distributed wheel set independently driven and steer-by-wire chassis according to claim 1, wherein: Based on the vehicle kinematic relationship and the steering demand signal, determine the deflection target values of each wheel group of the multi-wheel-group distributed electric drive configuration vehicle, including: Analyze the steering demand signal and vehicle speed demand signal in the motion demand signal, and determine the target deflection angle of each wheel group according to the preset steering mode demand by considering the vehicle kinematic parameter characteristics; Determine the target angular velocity of the deflection of each wheel group according to the first-order quantity of the steering demand signal collected by the differential link.

3. The steering control method of a distributed wheel set independently driven and steer-by-wire chassis according to claim 2, characterized in that: According to the position of the target steering center, the motion modes of the multi-wheel-group distributed electric drive configuration vehicle are divided into long-side steering, short-side steering, rotation in place, and translation; according to the actual needs, the motion modes of the multi-wheel-group distributed electric drive configuration vehicle are divided into normal steering, swing steering, in-place steering, lateral translation, crab walking, and any other position.

4. The steering control method of a distributed wheel set independent drive steer-by-wire chassis according to claim 2, characterized in that: According to the deflection target quantity and actual feedback value of each wheel group of the multi-wheel-group distributed electric drive configuration vehicle, determine the differential demand of each wheel group, and optimize and allocate the drive wheels assigned to each wheel group in real time according to the motion state feedback of the whole vehicle as the differential target speed, including: Based on the target deflection angle, target angular velocity of the deflection of each wheel group and the real vehicle feedback value, perform closed-loop control on the deflection actions of each wheel group respectively to determine the differential demand of each wheel group; Collect the motion state feedback of the whole vehicle in real time, apply the vehicle lateral stability control optimization algorithm, and reasonably allocate the differential demand of each wheel group to the drive wheels in each wheel group as the differential demand speed of the drive wheels.

5. The steering control method of a distributed wheel set independent drive steer-by-wire chassis according to claim 1, characterized in that: Based on the steering demand signal and the vehicle speed demand signal, determine the basic target speed of each wheel group of the multi-wheel-group distributed electric drive configuration vehicle after entering the target steady-state steering, including: Analyze the vehicle speed demand signal, and calculate the required speed of the drive wheels in each wheel group as the basic target speed in combination with the steering demand signal and the vehicle kinematic relationship; Further optimize the intervention timing of the basic target speed in combination with the real-time feedback of the wheel group deflection state.

6. The steering control method of a distributed wheel set independent drive steer-by-wire chassis according to claim 1, characterized in that: Each wheel set of the multi-wheel set distributed electric drive configuration vehicle includes two drive wheels, and each drive wheel is equipped with an independent drive motor and an encoder to real-time feedback the wheel speeds of each drive wheel. When a speed difference is formed between the two drive wheels of the same wheel set, the wheel set performs differential deflection around the central deflection axis, and an angular displacement sensor is equipped at the central deflection axis to feedback the deflection state of each wheel set.

7. The steering control method of a distributed wheel set independent drive steering by wire chassis according to claim 3, characterized in that: Based on the basic target speed and the differential target speed of the drive wheels in each wheel set, the drive motors of each drive wheel are regulated to achieve the steering control of the distributed wheel set independent drive steering by wire chassis, including: Superimpose the basic target speed and the differential target speed of the drive wheels in each wheel set as the target speed of the drive wheels in the corresponding wheel set, and input it into the motor drive control system of the multi-wheel set distributed electric drive configuration vehicle; The motor drive control system adjusts and controls the output torque of the drive motor of each drive wheel according to the target speed and the actual speed of the drive wheels in each wheel set to achieve the steering control of the distributed wheel set independent drive steering by wire chassis.

8. A steering control device for a distributed wheel set independently driven and steer-by-wire chassis, characterized in that, Including: An input module for real-time obtaining the motion demand signal of the multi-wheel set distributed electric drive configuration vehicle according to the path tracking situation; wherein, the motion demand signal includes a steering demand signal and a vehicle speed demand signal; A wheel set deflection target analysis module for determining the deflection target values of each wheel set of the multi-wheel set distributed electric drive configuration vehicle based on the steering demand signal according to the vehicle kinematic relationship; A wheel set deflection following control module for determining the differential demand of each wheel set according to the deflection target value and the actual feedback value of each wheel set of the multi-wheel set distributed electric drive configuration vehicle, and real-time optimizing and allocating the drive wheels of each wheel set according to the motion state feedback of the whole vehicle as the differential target speed; A wheel set basic target speed calculation module for determining the basic target speed of each wheel set of the multi-wheel set distributed electric drive configuration vehicle after entering the target steady-state steering according to the steering demand signal and the vehicle speed demand signal; A steering control module for regulating the drive motors of each drive wheel based on the basic target speed and the differential target speed of the drive wheels in each wheel set to achieve the steering control of the distributed wheel set independent drive steering by wire chassis.

9. An electronic device, comprising: At least one processor; And a memory communicatively connected to the at least one processor; wherein, the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the steps in the method according to any one of claims 1-7.

10. A non-transitory computer-readable storage medium storing computer instructions, wherein, The computer instructions are used to cause the computer to execute the steps in the method according to any one of claims 1-7.

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