Steering control method and device for distributed wheel-set independent drive steer-by-wire chassis

Abstract

The present invention discloses a steering control method and device for a distributed wheel-based independently driven steer-by-wire chassis. The method makes real-time decisions based on path tracking to obtain vehicle motion demand signals. The method then determines the target deflection value for each wheel group based on the vehicle's kinematic relationship. The desired differential speed for each wheel group is determined based on the target deflection value and actual feedback value, and the speed is distributed to each drive wheel in a coordinated manner. The method also calculates the base speed of each wheel (group) after entering the target steady-state steering state based on the vehicle speed demand signal and the steering demand signal. The target speed for each wheel is calculated by superimposing the desired differential speed for each wheel group and the base speed. The motor drive control system controls the output torque of each motor based on the target speed and actual speed of each drive wheel. The method effectively improves the maneuverability of special vehicles, enhances vehicle response speed, and achieves more ideal posture control, thereby effectively increasing operational efficiency, reducing the burden on personnel, and lowering emissions.

Description

Technical Field

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

[0002] As an important type of transport machinery, multi-axle special-purpose vehicles offer excellent load-bearing capacity and adaptability, making them widely used in the military, aerospace, and other fields. However, due to their large size and workload, their maneuverability and handling are often of particular concern.

[0003] At present, low-carbonization and intelligence of special vehicles have become important development directions. Due to their large weight and size, multi-axle special vehicles require a drive configuration and steering design that directly impacts their maneuverability, handling, and even energy efficiency. However, conventional multi-axle special vehicles currently suffer from the following deficiencies: First, conventional wheel-steering systems exhibit significant maneuverability deficiencies. To ensure accurate path tracking, the driver may need to repeatedly adjust the vehicle's posture, resulting in poor operating efficiency in some special scenarios and a complex steering mechanism design. Second, conventional multi-axle special vehicles widely employ hybrid and hydraulic drive configurations, resulting in complex transmission system designs and poor energy efficiency, which is inconsistent with the green development trend. Third, while the use of distributed electric drive combined with differential steering can effectively overcome these two deficiencies, it also places high demands on the overall vehicle control level. For example, failure to achieve effective synergy among the drive wheels can lead to severe tire wear and a surge in energy consumption, as well as tracking failure and even vehicle side slip. For example, the use of distributed McNabb steering often presents challenges in controlling vehicle lateral stability. Today, with the continuous iteration of electronic control technology and the development of vehicle-by-wire chassis technology, combined with the layout advantages of the domestic electric drive equipment industry, new possibilities have been provided for solving the controllability and energy consumption problems of multi-axle special vehicles.

[0004] Therefore, in order to address the problems of poor flexibility and maneuverability, poor operating efficiency and energy economy of traditional multi-axle special vehicles, a steering control method, device, equipment and storage medium for a distributed wheel-based independently driven steering-by-wire chassis are proposed. Summary of the Invention

[0005] The present invention is based on a distributed wheel-set independent differential electric drive configuration and a wire-controlled chassis technology, making full use of the fast, precise response and low-emission characteristics of direct motor drive, solving the problems of traditional multi-axle special vehicles in terms of poor maneuverability and energy economy, as well as poor posture control accuracy and tracking performance.

[0006] A first object of the present invention is to provide a steering control method for a distributed wheel-set independently driven steer-by-wire chassis, comprising:

[0007] According to the path tracking situation, the motion demand signal of the multi-wheel distributed electric drive configuration vehicle is obtained in real time; wherein the motion demand signal includes a steering demand signal and a vehicle speed demand signal;

[0008] Determine the deflection target value of each wheel group of a multi-wheel group distributed electric drive vehicle based on the vehicle kinematic relationship and the steering demand signal;

[0009] Based on the deflection target value and actual feedback value of each wheel group of the multi-wheel distributed electric drive configuration vehicle, the differential speed requirement of each wheel group is determined, and the drive wheel assigned to each wheel group is optimized in real time according to the motion state feedback of the entire vehicle as the differential target speed;

[0010] Determine the basic target speed of each wheel group of the multi-wheel group distributed electric drive vehicle after entering the target steady-state steering state based on the steering demand signal and the vehicle speed demand signal;

[0011] Based on the basic target speed and differential target speed of the driving wheels in each wheel group, the drive motor of each driving wheel is regulated to achieve steering control of the distributed wheel group independently driven steer-by-wire chassis.

[0012] Furthermore, according to the vehicle kinematic relationship and based on the steering demand signal, the deflection target value of each wheel group of the multi-wheel group distributed electric drive configuration vehicle is determined, including:

[0013] 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 requirements by considering the kinematic parameter characteristics of the entire vehicle;

[0014] The first-order quantity of the steering demand signal is collected according to the differential link to determine the target deflection angular velocity of each wheel group.

[0015] Furthermore, according to the location of the target turning center, the movement modes of the multi-wheel distributed electric drive configuration vehicle are divided into long-side steering, short-side steering, rotation and translation; according to actual needs, the movement modes of the multi-wheel distributed electric drive configuration vehicle are divided into normal steering, swinging, in-place steering, lateral movement, crab walking and other arbitrary positions.

[0016] Furthermore, the deflection target and actual feedback value of each wheel group of the multi-wheel distributed electric drive configuration vehicle are used to determine the differential speed requirements of each wheel group, and the drive wheels allocated to each wheel group are optimized in real time according to the motion state feedback of the entire vehicle as the differential target speed, including:

[0017] Based on the target deflection angle and target deflection angular velocity of each wheel group and the actual vehicle feedback value, the deflection action of each wheel group is controlled in a closed loop to determine the differential speed requirement of each wheel group;

[0018] Real-time feedback on the vehicle's motion status is collected, and the vehicle's lateral stability control optimization algorithm is applied to reasonably distribute the differential speed requirements of each wheel group to the driving wheels in each wheel group as the differential speed requirements of the driving wheels.

[0019] Furthermore, based on the steering demand signal and the vehicle speed demand signal, a basic target speed of each wheel group of the multi-wheel group distributed electric drive configuration vehicle after entering the target steady-state steering is determined, including:

[0020] Analyze the vehicle speed demand signal and, combined with the steering demand signal and vehicle kinematics, calculate the required speed of the drive wheels in each wheel group as the basic target speed;

[0021] Combined with real-time feedback on the wheel deflection status, the intervention timing of the basic target speed is further optimized.

[0022] Furthermore, each wheel group of the multi-wheel group distributed electric drive configuration vehicle includes two drive wheels, each drive wheel is equipped with an independent drive motor and encoder, and the wheel speed of each drive wheel is fed back in real time; when a speed difference is formed between the two drive wheels of the same wheel group, the wheel group performs differential deflection around the central deflection axis, and the central deflection axis is equipped with an angular displacement sensor for feeding back the deflection state of each wheel group.

[0023] Furthermore, based on the basic target speed and differential target speed of the driving wheels in each wheel group, the drive motor of each driving wheel is regulated to achieve steering control of the distributed wheel group independently driven steer-by-wire chassis, including:

[0024] The basic target speed and differential target speed of the driving wheels in each wheel group are superimposed to form the target speed of the driving wheels in the corresponding wheel group, and the target speed is input into the motor drive control system of the multi-wheel group distributed electric drive configuration vehicle;

[0025] 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 actual speed of the drive wheel in each wheel group, so as to realize the steering control of the distributed wheel group independently driven steer-by-wire chassis.

[0026] A second object of the present invention is to provide a steering control device for a steer-by-wire chassis with independently driven distributed wheel groups, comprising:

[0027] An input module is used to obtain, in real time, a motion demand signal of a multi-wheel distributed electric drive vehicle based on a path tracking condition; wherein the motion demand signal includes a steering demand signal and a vehicle speed demand signal;

[0028] The wheel deflection target parsing module is used to determine the deflection target value of each wheel group of a multi-wheel group distributed electric drive vehicle based on the vehicle kinematic relationship and the steering demand signal;

[0029] The wheel deflection following control module is used to determine the differential speed requirements of each wheel group based on the deflection target value and actual feedback value of each wheel group in a multi-wheel distributed electric drive configuration vehicle, and optimize the drive wheel assigned to each wheel group in real time based on the motion state feedback of the entire vehicle, as the differential target speed;

[0030] The basic target wheel speed calculation module is used to 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 according to the steering demand signal and the vehicle speed demand signal;

[0031] The steering control module is used to regulate the drive motor of each drive wheel based on the basic target speed and differential target speed of the drive wheels in each wheel group, so as to realize the steering control of the distributed wheel group independently driven steer-by-wire chassis.

[0032] The third object of the present invention is to provide 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 each step of the method described in the aforementioned technical solution.

[0033] 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 enable a computer to execute each step in the method described in the aforementioned technical solution.

[0034] Compared with the prior art, the advantages of the present invention are:

[0035] By designing a targeted steering control method, the present invention can fully leverage the structural advantages of a wire-controlled chassis special vehicle with a distributed wheel-based independent electric drive configuration. Utilizing the fast, precise response and high efficiency of direct motor drive, this method not only helps address the high vehicle control requirements of distributed wheel-based independent drive special vehicles, but also significantly reduces emissions by combining the supply advantages of the domestic electric drive equipment industry, thus complying with the development trend of green and environmentally friendly intelligent equipment.

[0036] The steering control method designed in this invention is applicable to special vehicles equipped with any number of wheel sets and is universal. It can perform real-time coordinated closed-loop control of each wheel (set) according to the upper-level motion requirements, enabling distributed wheel set wire-controlled electric drive special vehicles to achieve six driving maneuvers such as crab walking, swinging, and rotating in place that are difficult for traditional multi-axle special vehicles to complete. This significantly improves the vehicle's maneuverability and flexibility, which is conducive to improving the operating efficiency of special vehicles.

[0037] By designing wheel set deflection target analysis, deflection following control, and basic target speed calculation, the present invention implements a hierarchical coordinated control strategy for the target speed of each driving wheel, while taking into account the rate of change of the upper-level steering demand signal. This ensures that the target speed of each driving wheel set matches the motion requirements of the entire vehicle while improving the tracking speed and accuracy of the entire vehicle, thereby achieving more ideal path tracking and posture control requirements, which helps to reduce the burden on personnel.

[0038] The steering control method designed in the present invention can combine the real-time feedback of the deflection status of each wheel group and the movement status of the entire vehicle, and further compensate and optimize the output parameters of each part by applying various control algorithms. It has a broad control development space to ensure the driving stability of the vehicle under various working conditions, improve the control efficiency of the entire vehicle, reduce tire wear and unnecessary power loss, and further improve the energy consumption economy of the entire vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A schematic flow chart of a steering control method for a distributed wheel-set independently driven steer-by-wire chassis provided by the present invention;

[0040] Figure 2 A logic diagram of a steering control method for a distributed wheel-set independently driven steer-by-wire chassis provided by the present invention;

[0041] Figure 3 A schematic diagram showing the corresponding relationship between the wheel assembly mechanism, the target steering center, and the steering mode in a steering control method for a distributed wheel assembly independently driven steer-by-wire chassis provided by the present invention;

[0042] Figure 4 A diagram defining vehicle motion parameters in a steering control method for a distributed wheel-set independently driven steer-by-wire chassis provided by the present invention;

[0043] Figure 5 A schematic diagram of a motion mode in a steering control method for a steer-by-wire chassis with independently driven distributed wheels provided by the present invention;

[0044] Figure 6 The present invention is a schematic structural diagram of a steering control device for a steer-by-wire chassis with independently driven distributed wheels.

[0045] Figure 7 It is a structural schematic diagram of a non-transitory computer-readable storage medium storing computer instructions provided by the present invention. DETAILED DESCRIPTION

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0047] like Figure 1 and Figure 2 As shown, the present invention provides a steering control method for a distributed wheel group independently driven steering-by-wire chassis, comprising:

[0048] S110: According to the path tracking situation, a motion demand signal of the multi-wheel distributed electric drive configuration vehicle is obtained in real time; wherein the motion demand signal includes a steering demand signal and a vehicle speed demand signal.

[0049] The steering control method of the present invention is targeted at special vehicles with a multi-wheel distributed electric drive configuration (applicable to special vehicles equipped with any number of wheel sets). This embodiment is introduced using a four-axle special vehicle as an example.

[0050] In a specific embodiment, Figure 3 As shown in the , a single wheel set in its multi-wheel distributed electric drive configuration consists of two drive wheels, each of which can independently control drive and differential steering, and each drive wheel is equipped with an independently driven motor. A single drive wheel set consists of two drive wheels, each equipped with an independent drive motor and encoder, which can provide real-time feedback on the wheel speed of each drive wheel. When a speed difference forms between the two drive wheels, the wheel set can be differentially deflected about the central deflection axis. At the same time, an angular displacement sensor is installed on the rotation axis to provide real-time feedback on the deflection status of each wheel set.

[0051] Each wheel of a multi-wheel distributed electric drive vehicle can be independently and collaboratively controlled, enabling the vehicle to more quickly and accurately execute the driver's (autonomous driving unit's) path-tracking intent and achieve more ideal posture control. Compared to traditional multi-axle special-purpose vehicles, this configuration eliminates the need for complex steering and transmission mechanisms, contributing to lower energy consumption and emissions. Furthermore, the use of full-wire control leverages the highly flexible advantages of the distributed multi-wheel electric drive configuration, enabling the application of a variety of advanced modern control theories and offering broad development potential. Through coordinated control of each wheel, the vehicle can perform maneuvers beyond normal straight-line driving and steering, such as crab walks, self-rotations, and swings, effectively enhancing its maneuverability. Combined with the high-speed, high-precision response characteristics of the motor drive, this system works in conjunction with the distributed multi-wheel configuration to achieve more ideal path tracking and posture control, reducing the burden on personnel and significantly improving operational efficiency.

[0052] Specifically, this step includes the following steps:

[0053] S111: Analyze the steering demand signal and the 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 requirements by considering the kinematic parameter characteristics of the entire vehicle.

[0054] S112: To enhance the timeliness and accuracy of vehicle tracking and reduce high-frequency jitter and steady-state error, the first-order quantity of the steering demand signal is collected in combination with the differential link to determine the target deflection angular velocity of each wheel group.

[0055] In this embodiment, the motion demand signal, which serves as an input from the upper-level path tracking decision-making control link and can be used for both manual and autonomous driving, consists of a steering demand signal and a vehicle speed demand signal. This signal is analyzed in real time and combined with feedback from each wheel's deflection to implement closed-loop control. Furthermore, feedback from the vehicle's motion state is used for further real-time optimization, ultimately outputting the target speed for each drive wheel.

[0056] In this embodiment, a four-axle special vehicle is taken as an example, with a total of 8 wheel sets and 16 driving wheels, namely i =1~16, j =1~8; Closed-loop coordinated control of the specific actions of each drive wheel (group) enables special vehicles to complete faster and more accurate path tracking and posture control, while taking into account driving stability and energy economy under various working conditions, providing a solution to the difficult problem of distributed differential wheel group electric drive special vehicles requiring high vehicle control requirements.

[0057] S120: Determine the deflection target value of each wheel group of the multi-wheel group distributed electric drive configuration vehicle based on the vehicle kinematic relationship and the steering demand signal.

[0058] This step includes:

[0059] S121: Based on the target deflection angle, target deflection angular velocity, and actual vehicle feedback value of each wheel group, closed-loop control is performed on the deflection action of each wheel group to determine the differential speed requirement of each wheel group.

[0060] S122: To fully coordinate and optimize the drive wheel adhesion rate of each wheel group and ensure the dynamic stability and even tracking performance of the vehicle's steering, real-time feedback on the vehicle's motion state is collected, and the vehicle's lateral stability control optimization algorithm is applied to reasonably allocate the differential speed requirements of each wheel group to the drive wheels in each wheel group as the differential speed requirements of the drive wheels.

[0061] By analyzing the motion demand signal input from the driver or the automatic driving unit, considering the kinematic parameter characteristics of the entire vehicle, the target deflection angle of each wheel group is analyzed in real time according to different steering mode requirements; according to the location of the target steering center, it can be summarized into four major motion modes: long-side steering, short-side steering, rotation, and translation. According to actual needs, it can be further subdivided into six motion modes: normal steering, swinging, turning in place, lateral movement, crab walking, and other arbitrary positions; at the same time, in order to enhance the timeliness and accuracy of vehicle tracking, reduce high-frequency jitter and steady-state error, and better implement upper-level steering requirements, this module also combines the differential link to collect the first-order quantity of the steering demand signal, and analyzes the target deflection angular velocity of each wheel group in real time.

[0062] Specifically, for the convenience of description, the geometric parameters and motion parameters are defined as follows: Figure 4 As shown, Turn to the center for the target The angle relative to the horizontal line of the vehicle body, is the turning radius of the vehicle center, is the turning radius of each wheel center, is the actual deflection angle of each wheel group (relative to the horizontal direction of the vehicle body), is the longitudinal speed of the vehicle center, is the lateral speed of the vehicle center, is the vehicle's yaw angular velocity, is the vehicle center velocity, and are the geometric parameters of the vehicle body, It is the wheelbase between the two driving wheels in the wheel set.

[0063] For the four different types of movement modes of special vehicles, different movement demand signals need to be input. This process is decided in real time by the upper-level path tracking link based on the road conditions. According to actual needs, in addition to normal straight-line driving, the four different types of movement modes can be further divided into six movement modes: lateral movement, crab movement, normal steering, swinging, in-place steering, and other arbitrary steering center positions. Figure 5 As shown in the figure, lateral movement and crab maneuvering can be classified as translation, normal steering can be classified as long-side steering, swinging can be classified as short-side steering, and pivoting can be classified as rotation. In short, all steering maneuvers capable of the special vehicle can be summarized into the four major categories of motion. For the sake of a systematic description, this section introduces the four major categories of motion, namely long-side steering, short-side steering, rotation, and translation.

[0064] For the long side steering category, the input motion demand signal is ( and They are respectively the steering demand signal and the vehicle speed demand signal, the same below):

[0065]

[0066] That is, given the target turning center position and longitudinal target speed, Figure 4 Taking the case shown as an example, according to the vehicle kinematics, the turning radius at the center of each wheel group is It can be calculated as follows:

[0067]

[0068] The deflection angle of each wheel group The analysis is as follows:

[0069]

[0070] For the short-side steering category, the input motion demand signal is:

[0071]

[0072] That is, given the target turning center position and lateral target speed, Figure 4 As an example, the analysis process of the swing angle of each wheel group is the same as above, and only needs to be simply replaced and The geometric parameters of the vehicle body will not be described here.

[0073] For the rotation category, the input motion demand signal is:

[0074]

[0075] That is, given the angular velocity, such as Figure 4 Taking the case shown (steering in place) as an example, since the center of rotation is located at the center of the vehicle body, the swing angle of each wheel group is a fixed value:

[0076]

[0077] For translation mode, the input motion demand signal is:

[0078]

[0079] That is, the deflection angle of each wheel group and the longitudinal target speed are directly given, so that the swing angle of each wheel group matches the movement requirements of the vehicle body.

[0080] S130: Determine the differential speed requirements of each wheel group based on the deflection target value and actual feedback value of each wheel group of the multi-wheel group distributed electric drive configuration vehicle, and optimize the drive wheels assigned to each wheel group in real time based on the motion state feedback of the entire vehicle as the differential target speed.

[0081] This step specifically includes:

[0082] S131: Based on the target deflection angle, target deflection angular velocity, and actual vehicle feedback value of each wheel group, closed-loop control is performed on the deflection action of each wheel group to determine the differential speed requirement of each wheel group.

[0083] S132: Real-time feedback on the vehicle's motion state is collected, and the vehicle's lateral stability control optimization algorithm is applied to reasonably distribute the differential speed requirements of each wheel group to the driving wheels in each wheel group as the differential speed requirements of the driving wheels.

[0084] In an embodiment of the present invention, a proportional-differential-integral closed-loop controller is provided to perform closed-loop control on the deflection action of each wheel group according to the deflection target value (deflection angle and deflection angular velocity) of each wheel group and the actual vehicle feedback value, so as to determine the differential speed requirement of each wheel group; at the same time, in order to fully coordinate and optimize the adhesion rate of each driving wheel and ensure the dynamic stability and even tracking performance of the whole vehicle steering, the differential speed requirement of each wheel group can be reasonably distributed to the driving wheels on both sides by collecting the whole vehicle motion state feedback in real time and applying optimization algorithms such as the whole vehicle lateral stability control (the specific requirements need to be further designed and calibrated according to the actual working conditions) as the differential speed requirement of each driving wheel.

[0085] Specifically, the wheel deflection target values, namely the target deflection angle and target deflection angular velocity of each wheel, are calculated in real time by the wheel deflection target analysis module. The actual deflection state values, namely the deflection angle and deflection angular velocity, are fed back in real time by the angular displacement sensors equipped on each wheel. Both are used for closed-loop wheel deflection following control, enabling the vehicle to quickly and accurately execute path tracking and posture control requirements. This article briefly introduces the design of the wheel deflection following controller and defines the state deviation:

[0086]

[0087] in, and are the target deflection angle and target deflection angular velocity, respectively. and are the actual deflection angle and deflection angular velocity, respectively. and It is a proportional coefficient that can be used to adjust the importance of the deflection angle and deflection angular velocity.

[0088] definition The (total) differential speed requirement of each wheel set (j=1~8, representing 8 wheel sets):

[0089]

[0090] in and are the differential speed requirements of the two drive wheels on a single wheel set (i=1 to 16, representing 16 drive wheels). According to the proportional-differential-integral controller design, the deflection (total) differential speed requirement of each wheel set is expressed as:

[0091]

[0092] in, 、 and They are the proportional, integral and differential coefficients respectively, and their values ​​need to be debugged according to actual conditions.

[0093] Furthermore, the total differential speed demand of a single wheel set ultimately needs to be distributed to the drive wheels on both sides. Due to the unique characteristics and complexity of multi-wheel special vehicles, they place high demands on overall vehicle control. Therefore, to ensure coordinated wheel motion and overall vehicle energy efficiency, real-time vehicle motion state feedback can be collected through onboard IMU sensors. This is combined with methods such as slip distribution control, vehicle lateral stability control, and other optimization and compensation algorithms to coordinate the differential target speeds of the drive wheels. This further enhances vehicle performance indicators such as driving stability, tracking, and energy efficiency, thereby further improving operational efficiency.

[0094] The differential target speed distribution of the driving wheels on both sides of a single wheel set is as follows:

[0095]

[0096] in, is the distribution coefficient and can be further designed and developed, but the two target speeds must always meet the definition of "single wheel set (total) differential requirement" above.

[0097] S140: Determine a basic target rotational speed of each wheel group of the multi-wheel group distributed electric drive configuration vehicle after entering a target steady-state steering state based on the steering demand signal and the vehicle speed demand signal.

[0098] This step includes:

[0099] S141: Analyze the vehicle speed demand signal, and calculate the required rotation speed of the driving wheel in each wheel group as the basic target rotation speed in combination with the steering demand signal and the vehicle kinematic relationship.

[0100] S142: Based on the real-time feedback of the wheel deflection status, the intervention timing of the basic target speed is further optimized.

[0101] In a specific embodiment, the vehicle speed demand signals such as the throttle and brake input from the upper-level path tracking link are analyzed, and the required speed of each drive wheel is calculated in real time as the basic target speed in combination with the steering demand signal and the vehicle kinematic relationship; in addition, in order to avoid tire side slip and excessive wear, and cause additional interference to the control in the initial stage of steering, and improve the driving stability of the entire vehicle, its basic target speed can be combined with the real-time feedback of the wheel set deflection state for a certain delay intervention, and can be calibrated according to the actual working conditions.

[0102] The basic target speed of each driving wheel is determined based on the wheel motion relationship under the four motion modes of normal steering, swinging, rotation and crab walking, as well as the motion demand signal input from the upper layer.

[0103] For normal steering mode, given the vehicle steering center position , turning radius and longitudinal target speed After that, the vehicle's yaw angular velocity and center of mass velocity can be calculated as follows:

[0104]

[0105]

[0106] The basic target speed of each driving wheel (i=1~16) can be expressed as (G is the wheelbase):

[0107]

[0108] For the swing mode, the vehicle steering center position is given , turning radius and lateral target speed After that, the vehicle's yaw angular velocity and center of mass velocity can be calculated as follows:

[0109]

[0110]

[0111] The calculation method of the basic target speed of each driving wheel in normal steering mode, swing mode and rotation mode is the same.

[0112] For the crab mode, the target deflection angle of each wheel group is given (j=1~8) and longitudinal target speed Then the basic target speed of each driving wheel is (i=1~16) can be expressed as:

[0113]

[0114] S150: Based on the basic target speed and differential target speed of the driving wheels in each wheel group, the drive motor of each driving wheel is regulated to achieve steering control of the distributed wheel group independently driven steer-by-wire chassis.

[0115] According to the control strategy design, the final target speed of each driving wheel Can be expressed as differential target speed and base target speed The superposition of:

[0116]

[0117] The target speed of each motor is finally output to the motor drive control system. (I is the reduction ratio):

[0118]

[0119] Since the basic target speed is the required speed after entering steady-state steering, considering the complexity of the entire steering dynamic process of multi-axle vehicles, in order to avoid causing additional interference in the wheel deflection control stage in the initial steering stage and affecting driving stability and energy economy, the intervention of the basic target speed on the basic target speed can be further optimized in the time domain by comprehensively considering the feedback of the deflection state of each wheel group and the motion state of the entire vehicle.

[0120] like Figure 6 As shown, the present invention proposes a steering control device 600 for a steer-by-wire chassis with independently driven distributed wheels, comprising:

[0121] Input module 610 is used to obtain, in real time, a motion demand signal of the multi-wheel distributed electric drive vehicle according to the path tracking situation; wherein the motion demand signal includes a steering demand signal and a vehicle speed demand signal;

[0122] The wheel deflection target parsing module 620 is used to determine the deflection target value of each wheel group of the multi-wheel group distributed electric drive configuration vehicle based on the vehicle kinematic relationship and the steering demand signal;

[0123] The wheel group deflection following control module 630 is used to determine the differential speed requirements of each wheel group based on the deflection target value and actual feedback value of each wheel group of the multi-wheel group distributed electric drive configuration vehicle, and optimize the drive wheel assigned to each wheel group in real time according to the motion state feedback of the entire vehicle as the differential target speed;

[0124] The wheel group basic target speed calculation module 640 is used to 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 according to the steering demand signal and the vehicle speed demand signal;

[0125] The steering control module 650 is used to regulate the drive motor of each drive wheel based on the basic target speed and differential target speed of the drive wheel in each wheel group to achieve steering control of the distributed wheel group independently driven steer-by-wire chassis.

[0126] In order to implement the embodiment, the present invention also proposes an electronic device, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions that can be executed 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 each step in the aforementioned method.

[0127] like Figure 7 As shown, the non-transitory computer-readable storage medium includes a memory 810 of instructions and an interface 830, and the instructions can be executed by a processor 820 to complete the method. Alternatively, 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, an optical data storage device, etc.

[0128] In order to implement the embodiments, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method according to the embodiments of the present invention is implemented.

[0129] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the terms does not necessarily refer 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, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0130] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0131] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the invention includes alternative implementations in which functions may be performed out of the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the invention pertain.

[0132] The logic and / or steps represented in a flowchart or otherwise described herein, for example, can be considered a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" is 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 (not exhaustive) of computer-readable media include: an electrical connection having one or more wires (electronic devices), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and a portable compact disc read-only memory (CDROM). Furthermore, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing it in another suitable manner if necessary, and then storing it in a computer memory.

[0133] It should be understood that various components of the present invention may be implemented using hardware, software, firmware, or a combination thereof. In the described embodiments, multiple steps or methods may be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any of the following technologies known in the art or a combination thereof may be used: a discrete logic circuit having logic gates for implementing logic functions on data signals, an application-specific integrated circuit having suitable combinational logic gates, a programmable gate array (PGA), a field-programmable gate array (FPGA), etc.

[0134] Those skilled in the art will understand that all or part of the steps of the method for implementing the embodiment can be completed by instructing related 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 embodiment.

[0135] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing module, or each unit may exist physically separately, or two or more units may be integrated into a single module. The integrated module may be implemented in the form of hardware or in the form of a software functional module. If 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.

[0136] The storage medium mentioned above may be a read-only memory, a magnetic disk, or an optical disk, etc. Although the embodiments of the present invention have been shown and described above, it is understood that the embodiments are exemplary and are not to be construed as limiting the present invention. Those skilled in the art may make changes, modifications, substitutions, and variations to the embodiments within the scope of the present invention.

[0137] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A steering control method for a distributed wheel-driven, independently driven, steer-by-wire chassis, characterized in that: The method is applied to a special vehicle with a multi-wheel distributed electric drive configuration, including: According to the path tracking situation, a motion demand signal of the multi-wheel distributed electric drive configuration vehicle is obtained in real time; wherein the motion demand signal includes a steering demand signal and a vehicle speed demand signal; Determining a target deflection value for each wheel group of the multi-wheel group distributed electric drive vehicle based on the steering demand signal according to a vehicle kinematic relationship, wherein the target deflection value for each wheel group is a target deflection angle and a target deflection angular velocity of each wheel group; Each wheel set of the multi-wheel distributed electric drive vehicle includes two drive wheels, each equipped with an independent drive motor and encoder to provide real-time feedback on the wheel speed of each drive wheel. When a speed difference occurs between the two drive wheels of the same wheel set, the wheel set performs differential deflection around a central deflection axis. An angular displacement sensor is provided at the central deflection axis to provide feedback on the deflection state of each wheel set. Determining the differential speed requirements of each wheel group based on the deflection target value and actual feedback value of each wheel group of the multi-wheel group distributed electric drive configuration vehicle, and optimizing the drive wheels assigned to each wheel group in real time based on the motion state feedback of the entire vehicle as the differential target speed; Determining, based on the steering demand signal and the vehicle speed demand signal, a basic target rotational speed of each wheel group of the multi-wheel group distributed electric drive configuration vehicle after entering a target steady-state steering state; Based on the basic target speed and the differential target speed of the drive wheels in each wheel group, regulating the drive motor of each drive wheel to achieve steering control of the distributed wheel group independently driven steer-by-wire chassis; Determining a deflection target value 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 includes: Analyzing the steering demand signal and the vehicle speed demand signal in the motion demand signal, and determining the target deflection angle of each wheel group according to the preset steering mode requirements by considering the kinematic parameter characteristics of the entire vehicle; The first-order quantity of the steering demand signal is collected according to the differential link to determine the target deflection angular velocity of each wheel group; Determining the differential speed requirements of each wheel set based on the deflection target amount and actual feedback value of each wheel set of the multi-wheel set distributed electric drive configuration vehicle, and optimizing the drive wheels allocated to each wheel set in real time based on the motion state feedback of the entire vehicle as the differential target speed, including: Based on the target deflection angle and target deflection angular velocity of each wheel group and the actual vehicle feedback value, the deflection action of each wheel group is controlled in a closed loop to determine the differential speed requirement of each wheel group; Real-time feedback on the vehicle's motion status is collected, and the vehicle's lateral stability control optimization algorithm is applied to reasonably distribute the differential speed requirements of each wheel group to the driving wheels in each wheel group as the differential speed requirements of the driving wheels.

2. The steering control method for a distributed wheel-set independently driven steer-by-wire chassis according to claim 1, characterized in that: According to the location of the target turning center, the movement mode of the multi-wheel distributed electric drive configuration vehicle is divided into long-side steering, short-side steering, rotation and translation; according to actual needs, the movement mode of the multi-wheel distributed electric drive configuration vehicle is divided into normal steering, swinging, turning in place, lateral movement, crab walking and other arbitrary positions.

3. The steering control method for a distributed wheel-set independently driven steer-by-wire chassis according to claim 1, characterized in that: Determining, based on the steering demand signal and the vehicle speed demand signal, a basic target rotational speed of each wheel set of the multi-wheel set distributed electric drive configuration vehicle after entering a target steady-state steering state includes: parsing the vehicle speed demand signal and, in combination with the steering demand signal and the vehicle kinematics, calculating the required rotational speed of the driving wheels in each wheel set as a basic target rotational speed; Combined with real-time feedback on the wheel deflection status, the intervention timing of the basic target speed is further optimized.

4. The steering control method for a distributed wheel-set independently driven steer-by-wire chassis according to claim 2, characterized in that: Based on the basic target speed and the differential target speed of the driving wheels in each wheel group, the driving motor of each driving wheel is regulated to achieve steering control of the distributed wheel group independently driven steer-by-wire chassis, including: Superimposing the basic target speed of the driving wheels in each wheel group and the differential target speed as the target speed of the driving wheels in the corresponding wheel group, and inputting the target speed 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 actual speed of the drive wheel in each wheel group, so as to realize the steering control of the distributed wheel group independently driven steer-by-wire chassis.

5. A steering control device for a distributed wheel-set independently driven steer-by-wire chassis, which is controlled by the steering control method for a distributed wheel-set independently driven steer-by-wire chassis according to any one of claims 1 to 4, characterized in that: include: An input module is used to obtain a motion demand signal of a multi-wheel distributed electric drive vehicle in real time based on 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 parsing module, configured to determine a deflection target value of each wheel set of the multi-wheel set distributed electric drive configuration vehicle based on the vehicle kinematic relationship and the steering demand signal; A wheel set deflection following control module is used to determine the differential speed requirements of each wheel set based on the deflection target value and actual feedback value of each wheel set of the multi-wheel set distributed electric drive configuration vehicle, and optimize the drive wheel assigned to each wheel set in real time according to the motion state feedback of the entire vehicle as the differential target speed; a wheel group basic target speed calculation module, configured to determine a basic target speed of each wheel group of the multi-wheel group distributed electric drive configuration vehicle after entering a target steady-state steering state based on the steering demand signal and the vehicle speed demand signal; The steering control module is used to regulate the drive motor of each drive wheel based on the basic 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 independently driven steer-by-wire chassis.

6. 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 to enable the at least one processor to perform each step in the method according to any one of claims 1 to 4.

7. A non-transitory computer-readable storage medium storing computer instructions, wherein: The computer instructions are used to enable the computer to execute each step of the method according to any one of claims 1 to 4.

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