Double-steering module integrating active camber and active toe-in and control method

Abstract

The invention discloses a dual steering module integrating active camber and active toe-in functions and a control method thereof. The module comprises a wheel assembly, a first steering system, a second steering system and a suspension system. The double steering systems of the module are independent steering systems and have different kingpin positioning parameters, and decoupling control over wheel camber, wheel toe-in and a vehicle target turning angle can be achieved through relative rotation of the two steering systems. A master pin of the first steering system is perpendicular to a wheel grounding point, the toe-in angle of a wheel can be independently adjusted, the master pin can serve as a redundant backup of the second steering system, and the driving safety of the vehicle is improved. The second steering system serves as a main steering system, has reasonable main pin positioning parameters and can be matched with the first steering system to achieve camber angle adjustment of wheels. According to the module, active adjustment of the camber angle and the toe-in of the wheel can be achieved only through two sets of steering systems, and the control boundary of the vehicle is effectively expanded.

Description

Technical Field

[0001] The present invention relates to the field of intelligent wire-controlled chassis for electric vehicles, and in particular to a dual-steering module integrating active camber and active toe-in functions and a control method thereof. Background Art

[0002] From its inception, the chassis of modern automobiles can be divided into four major systems: drive, braking, steering, and suspension. These four systems were often initially designed with a centralized layout, but with advancements in the automotive industry, each system has begun to evolve toward a distributed layout. For example, the drive system has evolved from initially using a single engine to power the vehicle, to the dual-motor drive system found in electric vehicles, with one drive motor each on the front and rear axles, and to the future in-wheel motor drive system. This is a typical example of the transition from centralized to distributed. Current steering systems are also undergoing this process. Initially, steering systems only steered the two front wheels. Later, mechanical four-wheel steering technology developed, allowing simultaneous steering of all four wheels via the steering wheel. The advent of active rear-wheel steering technology has decoupled the movement of the front and rear wheels. However, even today, the rotation of the left and right wheels of a vehicle remains coupled. To address this issue, four-wheel independent steering (IWS) technology was developed. Because IWS decouples the rotation of the four wheels, it offers a high degree of freedom unavailable in traditional vehicles. Therefore, research on IWS will be a key focus for future research.

[0003] However, the lack of a mechanical connection between the steering system and the steering wheel threatens driving safety. Therefore, vehicles with four-wheel independent steering must consider installing a redundant system to ensure that the vehicle does not completely lose steering capability if the primary steering system fails. This, however, runs counter to the current development goals of lightweight and integrated vehicles. Therefore, a vehicle's redundant steering system should not simply serve as a backup mechanism but should assume more functions.

[0004] Wheel camber and toe are important parameters that influence vehicle handling and tire wear. Camber refers to the wheel's tilt relative to the vertical, while toe is the wheel's angle relative to the horizontal. Adjusting these angles can significantly impact a vehicle's grip, cornering precision, and tire life. In racing and high-performance vehicle design, precisely adjusting these parameters is crucial for enhancing vehicle dynamics. Currently, active adjustment of wheel camber and toe is often achieved using additional actuators, significantly increasing vehicle mass and wheel rim complexity. Therefore, integrating these with other actuators can enhance the vehicle's ultimate handling capabilities while maintaining lightweight performance. Summary of the Invention

[0005] To improve the safety and reliability of four-wheel independent steering vehicles and effectively expand the vehicle's control margins under extreme operating conditions, the present invention proposes a dual-steering module integrating active camber and active toe functions and its control method. It is characterized by:

[0006] A wheel assembly (100) is used to carry vehicle loads and internally integrates a drive system and a brake system for controlling longitudinal motion of the vehicle, wherein the drive system adopts an inner rotor hub motor drive mode to reduce the outer diameter volume, and the brake system adopts a wire control brake mode;

[0007] A first steering system (200) adopts a kingpin steering mode and serves as a backup system in case the main steering system fails. The system can independently adjust the wheel toe angle, and includes a first steering motor assembly and a first steering knuckle, wherein the first steering knuckle determines a first kingpin axis (K1); the first steering system cooperates with the wheel hub bearing of the wheel assembly and is fixedly connected to the drive system housing;

[0008] A second steering system (300) adopts a tie rod steering form and is a main steering system, which can cooperate with the first steering system to realize active adjustment of the wheel camber angle decoupled from the wheel angle, and includes a steering tie rod and a second steering knuckle, wherein the second steering knuckle determines a second kingpin axis (K2); the second steering knuckle is connected to the first steering knuckle by a hinge and is fixedly connected to the first steering motor assembly;

[0009] The suspension system (400) is an unequal length double wishbone suspension, comprising upper and lower control arms, a shock absorber bracket and a shock absorbing spring assembly; the suspension system is connected to the second steering knuckle of the second steering system via a ball pin, and is used to mitigate road impact and improve vehicle ride comfort.

[0010] Preferably, the first kingpin axis (K1) is characterized by:

[0011] The first kingpin axis (K1) should be approximately or completely perpendicular to the wheel ground plane to ensure independent adjustment of the wheel toe. At the same time, this configuration is convenient for cooperating with the second steering system to achieve active wheel camber angle adjustment decoupled from the wheel angle.

[0012] Preferably, the second kingpin axis (K2) is characterized by:

[0013] The second kingpin axis (K2), serving as the kingpin axis of the main steering system, should be designed with kingpin positioning parameters that first meet the vehicle's high-speed handling stability requirements, and then consider meeting the required wheel camber active adjustment range. The specific design process is as follows:

[0014] S0: Start;

[0015] S1: Design the initial values ​​of the kingpin positioning parameters β0, γ0 of the second kingpin axis according to the vehicle's high-speed handling stability requirements;

[0016] S2: Substitute the active camber angle range calculation formula into:

[0017]

[0018] Where α(δ2) is the wheel camber angle change angle; β0 and γ0 are the initial design values ​​of the kingpin inclination angle and the kingpin caster angle of the second kingpin axis respectively; δ2 is the angle of the wheel turned by the second steering system for adjusting the wheel camber angle; the maximum and minimum change angles of the wheel camber angle are α max =max(α(δ2)) and α min =min(α(δ2));

[0019] S3: Determine whether the active camber angle variation range meets the design requirements. If so, execute S4. If not, return to S1 and redesign.

[0020] S4: End.

[0021] Preferably, the wheel assembly (100) is characterized by comprising:

[0022] The wheel hub (102) is divided into a rim and a spoke. The rim is ring-shaped and used to mount the tire (101). Edges are provided on both sides to prevent the tire from falling off. The spoke is composed of a plurality of spokes. An end nut through hole is provided at the center of the spoke connection. A plurality of brake disc through holes are provided around the end nut through hole.

[0023] A brake disc (103) is provided with a through hole at the center and threaded holes around it, and is fixedly connected to the brake disc through hole of the wheel hub via bolts;

[0024] A hub flange (104) is provided with a spline groove through hole at the center and a plurality of threaded through holes on the flange, and is connected to the hub and the brake disc by bolts;

[0025] A wheel hub bearing (105) is a tapered roller bearing, mounted between the outer diameter of the wheel hub flange end and the first steering knuckle of the first steering system (200), for reducing friction loss during wheel rotation and carrying radial and axial loads during vehicle operation;

[0026] A brake caliper (106) is a floating caliper type, clamped at the outer edge of the brake disc, and leaving a suitable braking gap;

[0027] The drive system assembly (107) includes a drive motor and a drive system reducer. A drive system assembly output shaft is provided at the center, which is provided with splines and threads and is connected to the hub flange through splines and end nuts.

[0028] Preferably, the drive system assembly (107) is characterized by:

[0029] An inner rotor drive motor and a coaxially arranged drive system reducer are integrated internally, and the drive system reducer adopts a planetary gear reduction mechanism; the output torque of the inner rotor drive motor is decelerated by the drive system reducer and then output from the output end of the drive system reducer, i.e., the output shaft of the drive system assembly; the drive system assembly is provided with a plurality of mounting threaded holes on the wheel-side end surface, and is fixedly connected to the first steering knuckle of the first steering system (200) by screws, and moves as a whole with the deflection of the first steering knuckle.

[0030] Preferably, the first steering system (200) is characterized by comprising:

[0031] A first steering motor assembly (201) includes a first steering motor and a first steering reducer, a lug is provided at the tail portion, and an output shaft of the first steering motor assembly is provided at the head portion, wherein the output shaft is provided with an external spline and an external thread;

[0032] The first steering knuckle (202) has a main body in the shape of a circular plate, a transmission shaft through hole is provided in the center for passing the output shaft of the drive motor assembly, and drive system through holes are provided around it, which is connected to the drive motor assembly by screws, and an inner hole boss is provided on the wheel side surface, and the inner hole of the boss cooperates with the wheel hub bearing; a circular groove is provided on the body side for radial positioning and fixing the drive system of the wheel assembly (100); two "L"-shaped support arms are provided on the upper and lower surfaces, and vertical through holes are provided on the end surfaces of the upper and lower support arms respectively, and the center line of the upper and lower through holes is used to determine the first kingpin axis (K1); a spline is provided in the upper support arm through hole, which cooperates with the outer spline of the output shaft of the first steering motor assembly and is axially limited by an end nut; a pair of brake caliper lugs are provided on the front side of the first steering knuckle for installing the brake caliper.

[0033] Preferably, the first steering motor assembly (201) is characterized by:

[0034] A first steering motor and a first steering reducer are integrated internally. The first steering motor should have good control accuracy so as to realize accurate control of the wheel angle. A lug with a through hole is provided at the rear of the first steering motor housing for fixing to the second steering knuckle of the second steering system (300); the output end of the first steering motor is spline-connected with the input end of the first steering reducer; the first steering reducer adopts a worm gear reducer, which not only ensures a larger transmission ratio and thus reduces the volume of the first steering reducer, but also ensures that the first steering system has a reverse self-locking capability and thus reduces the energy consumption of the motor at the end of the controlled movement; the output shaft of the first steering reducer is the output shaft of the first steering motor assembly, and its axis is rotated 90 degrees relative to the axis of the first steering motor, and is provided with splines and threads.

[0035] Preferably, the second steering system (300) is characterized by comprising:

[0036] The second steering knuckle (301) is in an "E" shape as a whole, and has three support arms (upper, middle and lower) and a main arm, wherein the top surface of the lower support arm is connected to the through hole of the lower support arm of the first steering knuckle by a pin shaft, the center point of which constitutes the lower end point of the first main pin axis (K1), and the lower end surface of the lower support arm is also provided with a ball pin threaded hole; the head of the middle support arm is punched with a through hole for passing the output shaft of the first steering motor assembly, the center point of which constitutes the upper end point of the first main pin axis (K1); the top surface of the head of the upper support arm is provided with a ball pin threaded hole, which together with the ball pin threaded hole of the lower support arm determines the second steering axis (K2); the main arm is fixedly connected to the three support arms as a whole, and the upper and lower end surfaces of the connection between the main arm and the middle support arm are respectively provided with the first steering motor assembly mounting hole and the steering tie rod support arm, wherein the steering tie rod support arm is fixedly connected to the main arm as a whole, and the end thereof is provided with a ball pin mounting hole; the shape design of the second steering knuckle should avoid motion interference with other parts during wheel steering and active camber and toe angle changes;

[0037] The steering rod (302) is rod-shaped as a whole, and has a ball pin support at its head, which is connected to the ball pin mounting hole of the second steering knuckle steering rod support arm through a ball pin; the steering rod can control the second steering knuckle (301) to deflect around the second steering axis (K2) under the drag of a mechanical steering transmission mechanism or an electromechanical actuator, thereby realizing a non-decoupled mechanical steering function and a decoupled wire-controlled steering function respectively.

[0038] Preferably, the suspension system (400) is characterized by comprising:

[0039] The lower control arm (401) is generally A-shaped and has two cross swing arms and a transverse arm. A ball pin support is provided at the intersection of the swing arms and is connected to the ball pin hole of the second steering knuckle lower support arm through a ball pin. The center of the ball pin constitutes the lower end point of the second kingpin axis (K2). The tails of the two swing arms are each provided with a boss through-hole for connecting to the vehicle body or subframe through a hinge. A shock absorber lug is provided in the middle of the transverse arm.

[0040] The shock absorber bracket (402) has a shock absorber mounting hole on the top and a threaded lug for adjusting the diameter of the mounting hole; two arc-shaped support arms are provided at the bottom, and a lower control arm lug is provided at the bottom of the support arm and is connected to the lower control arm shock absorber lug via a pin shaft;

[0041] The damping spring assembly (403) has a shock absorber and a coil spring integrated therein, and the two are coaxially arranged; a lug is provided on the top and connected to the vehicle body or subframe via a pin; a support rod is provided on the bottom and is installed in the mounting hole of the shock absorber bracket; the shock absorber can be a passive hydraulic shock absorber, an adjustable damping shock absorber, or even an electric shock absorber for active suspension;

[0042] The upper control arm (404) is composed of two crossed swing arms. A ball pin support is provided at the intersection of the swing arms and is connected to the ball pin hole of the second steering knuckle upper support arm through a ball pin. The center point of the ball pin constitutes the upper end point of the second kingpin axis (K2). The tail of each swing arm is provided with a boss through hole for connecting to the vehicle body or subframe through a hinge. It should be ensured that there is no motion interference with the shock absorbing spring assembly during vehicle operation.

[0043] Preferably, the control method of the dual-steering module includes:

[0044] S0: Start;

[0045] S1: The dual steering module controller receives a command signal from the upper computing unit to adjust the wheel camber angle, adjust the wheel toe, or perform wheel steering movement;

[0046] S2: The dual-steering module controller reads the kingpin positioning parameters β and γ of the second steering system of the vehicle from the storage unit, where β is the kingpin inclination angle and γ is the kingpin caster angle;

[0047] S3: The dual steering module controller analyzes the command signal and determines the current steering mode of the vehicle. If it is the normal steering mode, S4 is executed; if it is the steering fault tolerance mode, S8 is executed.

[0048] S4: The dual steering module controller analyzes the command signal to determine whether to enter the active camber mode. If the active camber mode is entered, execute S5; otherwise, execute S6;

[0049] S5: The dual steering module controller calculates the wheel adjustment angle δ for the vehicle to change the wheel camber angle through formula 1 c , and execute S7;

[0050] S6: The dual-steering module controller calculates the target turning angles δ1 and δ2 of the first and second steering systems using Formula 2, and executes S9;

[0051] S7: The dual-steering module controller calculates the target turning angles δ1 and δ2 of the first and second steering systems using Formula 3, and executes S9;

[0052] S8: The dual-steering module controller calculates the target turning angles δ1 and δ2 of the first and second steering systems using Formula 4, and executes S9;

[0053] S9: The dual steering module controller controls the first and second steering systems to achieve the desired target steering angles δ1 and δ2;

[0054] S10: End;

[0055] The normal steering mode is when there is no steering system fault signal, the vehicle can steer through the second steering system, which is the main steering system. The steering fault-tolerant mode is when a fault signal from the second steering system is received, the vehicle cannot continue to steer through the second steering system, and can only steer through the first steering system. Therefore, the active camber mode cannot be entered at this time. At this time, the first steering system becomes the backup steering system, ensuring that the vehicle still has the steering capability in the event of a main steering system failure, thereby ensuring the safety of the steer-by-wire function.

[0056] The active camber mode is determined by determining whether the desired camber angle α is zero. If it is zero, the active camber mode is not entered, and in this mode, the second steering system is the main steering system, and the first steering system is only used for adjusting the wheel toe angle. If it is not zero, the active camber mode is entered, and the first and second steering systems cooperate with each other to achieve controllable adjustment of the wheel camber angle without changing the wheel deflection angle or toe angle.

[0057] Wherein the formula 1 is:

[0058]

[0059] in This formula is used to calculate the wheel adjustment angle δ for wheel camber change c ; Formula 2 is:

[0060]

[0061] where δ t ,δw are the desired toe angle and the desired wheel turning angle of the vehicle respectively; the formula 3 is:

[0062]

[0063] The formula 4 is:

[0064]

[0065] Due to the presence of the kingpin alignment parameter of the second steering system, the wheel camber angle will also change during the vehicle's conventional steering process. However, unlike the decoupling control of the wheel camber angle and wheel steering angle in the active camber mode, the wheel camber angle and wheel steering angle in the conventional steering process have an inherent coupling relationship common to all current suspension systems.

[0066] The dual steering module controller should adopt a closed-loop control method to control the first and second steering systems to achieve the desired target turning angles to improve control accuracy.

[0067] Beneficial effects of the present invention:

[0068] 1. This invention proposes a dual-steering module that integrates active camber and active toe functions, adopts four-wheel independent steering technology, which can effectively improve the vehicle's degree of freedom, expand the vehicle's control boundaries, and realize special steering technologies that traditional vehicles cannot achieve.

[0069] 2. The present invention proposes a dual-steering module that integrates active camber and active toe functions. Based on the four-wheel independent steering technology, a second steering backup system is proposed, which can effectively improve the safety and reliability of four-wheel independent steering vehicles. At the same time, in order to adapt to the times, the second steering system is integrated with other systems to realize more functions and improve vehicle integration.

[0070] 3. The present invention proposes a dual-steering module that integrates active camber and active toe functions. Without adding additional actuators, the active variable camber and active variable toe functions are integrated into it, further improving the control boundary under the vehicle's extreme working conditions. At the same time, a set of high-precision control methods for the active variable camber and active variable toe functions of the dual-steering module are proposed, realizing decoupled control between the wheel camber angle, toe angle and wheel steering angle. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 This is a schematic diagram of the assembly of a dual steering module integrating active camber and active toe according to the present invention.

[0072] Figure 2 This is an exploded view of the parts of a dual steering module integrating active camber and active toe as described in the present invention.

[0073] Figure 3 This is a schematic diagram of kingpin positioning parameters for a dual steering module integrating active camber and active toe according to the present invention.

[0074] Figure 4 This is a schematic diagram of the maximum wheel camber angle of a dual steering module integrating active camber and active toe according to the present invention.

[0075] Figure 5 This is a schematic diagram of the minimum wheel camber angle of the dual steering module integrating active camber and active toe according to the present invention.

[0076] Figure 6 This is a design flow chart of a dual steering module integrating active camber and active toe according to the present invention.

[0077] Figure 7 This is a control block diagram of a dual steering module integrating active camber and active toe according to the present invention. Specific implementation plan

[0078] The present invention will be described in further detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0079] The present invention proposes a dual steering module integrating active camber and active toe, characterized in that it comprises: a wheel assembly (100), a first steering system (200), a second steering system (300) and a suspension system (400). Figure 1 shown.

[0080] The wheel assembly (100) comprises a wheel hub (102), a brake disc (103), a wheel hub flange (104), a wheel hub bearing (105), a brake caliper (106) and a drive system assembly (107), and is used to carry vehicle loads. The internally integrated drive system and brake system are used for longitudinal control of the vehicle, wherein the drive system adopts the drive form of an inner rotor wheel hub motor, and the brake system adopts the form of wire control brake;

[0081] The wheel hub (102) is divided into a rim and a spoke as a whole. The rim is ring-shaped and used to mount the tire (101). Edges are provided on both sides to prevent the tire from falling off. The spokes are composed of a plurality of spokes. The shape of the spokes should be designed to ensure that there is no motion interference with the internal brake caliper and the first steering motor assembly during normal rotation of the wheel. An end nut through hole is provided at the center of the spoke connection. A plurality of brake disc through holes are provided around the end nut through hole. The brake disc through hole should be designed with a countersunk hole to ensure good aerodynamics during vehicle driving. The tire can be a traditional pneumatic tire, a non-pneumatic tire or other new tires.

[0082] The brake disc (103) is flange-shaped as a whole, with a through hole at the center and hub through holes around it. It is connected to the brake disc through holes of the hub by bolts and rotates together with the wheel. The brake disc is made of a material with good wear resistance. At the same time, in order to ensure its heat dissipation characteristics, a material with good thermal conductivity should be selected.

[0083] The hub flange (104) has a spline groove through hole at its center for transmitting the driving torque from the drive system, and its wheel side surface and end outer surface should have good processing characteristics to ensure the matching characteristics with the hub bearing, and the wheel side surface is used to transmit the lateral force at the wheel, and a plurality of through holes are provided on the flange, which are fixedly connected to the brake disc through hole of the hub and the brake disc hub through hole by bolts;

[0084] The wheel hub bearing (105) is arranged in a back-to-back manner with two sets of tapered roller bearings to obtain higher axial and radial stiffness. The wheel hub bearing is installed at the end of the wheel hub flange to reduce friction during wheel rotation and to carry radial and axial loads during vehicle operation.

[0085] The brake caliper (106) is a floating caliper brake, which is in a "C" shape as a whole and is clamped at the outer edge of the brake disc, leaving a suitable braking gap. The brake caliper should adopt a wire-controlled hydraulic actuation method, but in some examples, it can also adopt an electronic mechanical brake or an electronic wedge brake method;

[0086] The drive system assembly (107) is internally integrated with an inner rotor drive motor and a drive system reducer. The output torque of the inner rotor drive motor is decelerated by the drive system reducer and then output from the output shaft of the drive motor assembly. The output shaft of the inner rotor drive motor and the input end of the drive system reducer are connected by a spline. The output end of the drive system reducer is the output shaft of the drive motor assembly. The input end and the output end of the drive system reducer are coaxially arranged. In some embodiments, a planetary gear or a harmonic gear transmission form can be adopted. A plurality of mounting threaded holes are provided on the outer end face of the wheel of the shell of the drive system assembly. The output shaft of the drive system assembly extends from the center and is provided with splines and threads. The output shaft is connected to the hub flange by splines and end nuts.

[0087] The first steering system (200) comprises a first steering motor assembly (201) and a first steering knuckle (202), adopts a kingpin steering mode, and serves as a backup system after the main steering system fails, and can independently adjust the wheel toe, wherein the first steering knuckle is used to determine a first kingpin axis (K1); the first steering system cooperates with the wheel hub bearing of the wheel assembly and is fixedly connected to the drive system assembly by screws;

[0088] The first steering motor assembly (201) internally integrates a first steering motor and a first steering reducer. The first steering motor should have good control accuracy so as to achieve precise control of the wheel angle. The tail of the first steering motor housing is provided with a lug with a through hole for installation and fixation on the second steering system. The first steering reducer should adopt a worm gear reducer, which can ensure a larger transmission ratio and thus reduce the volume of the first steering reducer, and ensure that the first steering system has a self-locking ability and thus reduces energy consumption. The output shaft of the first steering reducer is the output shaft of the first steering motor assembly. The first steering motor and the first steering reducer should be connected by a spline. The output shaft of the first steering motor assembly should be provided with a spline and a thread and installed on the first steering knuckle.

[0089] The first steering knuckle (202) is in the shape of a circular plate, with a transmission shaft through hole in the center for passing the output shaft of the drive motor assembly, and drive system through holes around it, which are connected to the mounting holes of the drive motor assembly by screws. A boss is provided on the side surface of the wheel to cooperate with the wheel hub bearing, so a good processing surface is required to ensure the matching characteristics with the bearing; a circular groove is provided on the side of the vehicle body for fixing the drive motor assembly; two "L"-shaped support arms are provided on the upper and lower surfaces, and a spline groove and a through hole are provided on the end surfaces of the upper and lower support arms respectively for determining the first kingpin axis (K1), wherein the height of the upper and lower support arms should ensure that there is no motion interference with the brake disc after the vehicle is assembled; a brake caliper lug is provided on the front side of the first steering knuckle for installing the brake caliper, and a boss is provided at the end of the lug to reduce the processing surface.

[0090] The second steering system (300) adopts a tie rod steering form and is a main steering system, including a second steering knuckle (301) and a steering tie rod (302). By cooperating with the first steering system, active adjustment of the wheel camber angle decoupled from the wheel steering angle can be achieved, wherein the second steering knuckle determines a second kingpin axis (K2); the second steering system is connected to the first steering knuckle via a hinge and is fixedly connected to the stator part of the first steering motor assembly. In some examples, the second steering system can be changed from tie rod steering to kingpin steering similar to the first steering system, that is, the steering tie rod is eliminated and a second steering motor is installed between the second steering knuckle and the upper control arm for rotating the second steering knuckle;

[0091] The second steering knuckle (301) is in an "E" shape as a whole and is a high-throw steering knuckle having three arms, an upper arm, a middle arm and a lower arm, wherein the top surface of the lower arm is connected to the through hole of the lower arm of the first steering knuckle by a pin shaft, forming the lower end point of the first main pin axis (K1), and the lower end surface of the lower arm is also provided with a ball pin threaded hole; the head of the middle arm is provided with a through hole for passing the output shaft of the first steering motor assembly, forming the upper end point of the first main pin axis (K1); the top surface of the head of the upper arm is provided with a ball pin threaded hole, which together with the ball pin threaded hole of the lower arm determines the second steering axis (K2); the connection between the main arm and the three arms should be provided with a suitable fillet to avoid stress concentration, the rear end surface of the connection between the main arm and the middle arm is provided with a first steering motor assembly mounting hole and a steering tie rod arm, the first steering motor assembly mounting hole should be provided with a boss to reduce the processing surface, and the lower end surface of the head of the steering tie rod arm is provided with a ball pin mounting hole; the shape design of the second steering knuckle should avoid interference with other parts during wheel steering.

[0092] The steering tie rod (302) is rod-shaped as a whole, and a ball pin support is provided at the head thereof, which is connected to the ball pin mounting hole of the second steering knuckle steering tie rod support arm via a ball pin.

[0093] The suspension system (400) is an unequal-length double wishbone suspension, comprising a lower control arm (401), a shock absorber bracket (402), a shock-absorbing spring assembly (403), and an upper control arm (404); the suspension system is connected to the second steering system via a ball pin, for alleviating road impact and improving vehicle ride comfort; in some instances, the ball pin hole on the upper support arm of the second steering knuckle can be eliminated and replaced with a shock absorber mounting hole for mounting the suspension shock absorber, thereby replacing the double wishbone suspension of the suspension system with a McPherson suspension; in other instances, an active actuator can be added to further improve the vertical control capability of the vehicle, and the mounting position can be on the upper and lower control arms or the second steering knuckle.

[0094] The lower control arm (401) is generally A-shaped and has two cross swing arms and a transverse arm. A ball pin support is provided at the intersection of the swing arms and is connected to the ball pin hole of the second steering knuckle lower support arm through a ball pin, and the center of the ball pin constitutes the lower end point of the second kingpin axis (K2); the tails of the two swing arms are provided with a boss through hole for connecting to the vehicle body or subframe through a hinge; a shock absorber lug is provided on the top surface of the transverse arm; and grooves are provided on the sides of the two swing arms and the transverse arm to reduce the weight of the parts;

[0095] The shock absorber bracket (402) is provided with a shock absorber mounting hole on the top and a threaded hole for fastening; two arc-shaped support arms are provided on the bottom, and a lower control arm lug is provided on the bottom of the support arm and is connected to the lower control arm shock absorber lug via a pin shaft;

[0096] The damping spring assembly (403) is internally integrated with a hydraulic shock absorber and a coil spring, which are coaxially arranged; a lug is provided on the top and connected to the vehicle body or subframe via a pin; a support rod is provided on the bottom and installed in the mounting hole of the shock absorber bracket. In some examples, the hydraulic shock absorber of the damping spring assembly can be replaced with a shock absorber such as an electromagnetic shock absorber or a magnetorheological fluid shock absorber, and the coil spring can also be replaced with a shock absorber such as an air spring or an oil-gas spring;

[0097] The upper control arm (404) is composed of two crossed swing arms, a ball pin support is provided at the intersection of the swing arms and is connected to the ball pin hole of the second steering knuckle upper support arm through a ball pin, and the center point of the ball pin constitutes the upper end point of the second kingpin axis (K2); the tail of each swing arm is provided with a boss through hole for connecting to the vehicle body or subframe through a hinge; and there should be no motion interference with the shock absorbing spring assembly during vehicle operation;

[0098] The first kingpin axis (K1) is as follows Figure 3 As shown in β1 and γ1, they should be approximately or completely perpendicular to the wheel ground plane to facilitate independent adjustment of the wheel toe and to facilitate cooperation with the second steering system to achieve active wheel camber angle adjustment decoupled from the wheel angle.

[0099] The second kingpin axis (K2) is as follows Figure 3 As shown in β2 and γ2 in , as the kingpin axis of the main steering system, the design of its kingpin positioning parameters should first meet the vehicle's high-speed handling stability requirements. For example, designing a suitable camber angle can help improve the vehicle's stability and self-centering ability during steering, and reduce skidding and instability caused by improper geometry of the suspension system. Too large a camber angle may cause wear on the inside of the tire; too small an angle may cause poor steering self-centering force. A proper caster angle can improve the vehicle's straight-line stability and steering self-centering force. Too large a caster angle will make the steering heavy, and too small an angle may cause instability in the vehicle during high-speed driving. On this basis, consider meeting the required active adjustment range of the wheel camber angle. As Figure 6 As shown in the figure, the specific design process is:

[0100] S0: Start;

[0101] S1: Design the initial values ​​of the kingpin positioning parameters β0, θ0 of the second kingpin axis according to the vehicle's high-speed handling stability requirements;

[0102] S2: Substitute the active camber angle range calculation formula into:

[0103]

[0104] Where α(δ2) is the wheel camber angle change angle; β0 and θ0 are the initial design values ​​of the kingpin inclination angle and the kingpin caster angle of the second kingpin axis respectively; δ2 is the wheel turning angle used by the second steering system for wheel camber angle change; the maximum and minimum wheel camber angle change angles are α respectively max =max(α(δ2)) and α min =min(α(δ2));

[0105] S3: Determine whether the active camber angle variation range meets the design requirements. If so, execute S4. If not, return to S1 and redesign.

[0106] S4: End.

[0107] The initial design values ​​of the kingpin inclination angle and the kingpin caster angle of the second kingpin axis designed through the above process can be used as the final design values.

[0108] The control method of the dual steering module integrating active camber and active toe can realize the decoupling control of active wheel camber angle, active toe and wheel angle. Figure 7 As shown, it specifically includes:

[0109] S0: Start;

[0110] S1: The dual steering module controller receives the command signal from the upper computing unit;

[0111] S2: The dual-steering module controller reads the kingpin positioning parameters β and γ of the second steering system of the vehicle stored in the storage unit, where β is the kingpin inclination angle and γ is the kingpin caster angle;

[0112] S3: The dual steering module controller analyzes the command signal and determines the current steering mode of the vehicle. If it is the normal steering mode, S4 is executed; if it is the steering fault tolerance mode, S8 is executed.

[0113] S4: The dual steering module controller analyzes the command signal to determine whether to enter the active camber mode. If the active camber mode is entered, execute S5; otherwise, execute S6;

[0114] S5: The dual steering module controller calculates the wheel adjustment angle δ for the vehicle to change the wheel camber angle through formula 1 c , and execute S7;

[0115] S6: The dual-steering module controller calculates the target turning angles δ1 and δ2 of the first and second steering systems using Formula 2, and executes S9;

[0116] S7: The dual-steering module controller calculates the target turning angles δ1 and δ2 of the first and second steering systems using Formula 3, and executes S9;

[0117] S8: The dual-steering module controller calculates the target steering angles δ1 and δ2 of the first and second steering systems using Formula 4, and executes S9;

[0118] S9: The dual steering module controller controls the first and second steering systems to achieve the desired target steering angles δ1 and δ2.

[0119] S10: End.

[0120] The normal steering mode, i.e., when there is no steering system fault signal, steering can be performed by the second steering system; the steering fault tolerance mode, i.e., when a fault signal of the second steering system is received, steering can no longer be performed by the second steering system, and steering can only be performed by the first steering system, and the active camber mode cannot be entered at this time;

[0121] The active camber mode is determined by determining whether the desired camber angle α is zero. If it is zero, the active camber mode is not entered, and in this mode, the second steering system serves as the primary steering system, and the first steering system is only used for adjusting the wheel toe angle. If it is not zero, the active camber mode is entered, and the wheel camber angle is changed by the cooperation between the first and second steering systems.

[0122] Wherein the formula 1 is:

[0123]

[0124] in This formula is used to calculate the wheel adjustment angle δ for wheel camber change c ; Formula 2 is:

[0125]

[0126] where δ t ,δ w are the desired toe angle and the desired wheel turning angle of the vehicle respectively; the formula 3 is:

[0127]

[0128] The formula 4 is:

[0129]

[0130] Due to the presence of the kingpin alignment parameter of the second steering system, the wheel camber angle will also change during the vehicle's conventional steering process. However, unlike the decoupling control of the wheel camber angle and the wheel steering angle in the active camber mode, the wheel camber angle and the wheel steering angle are coupled during conventional steering.

[0131] Among them Figure 4 、 5 As shown, it shows the maximum and minimum camber angles that the wheels can reach, taking the second steering system with a kingpin inclination angle of 6°, a kingpin caster angle of 8°, and a maximum steering angle of 30° of the first steering system as an example, where the maximum camber angle is 3.2° and the minimum camber angle is -4.8°.

[0132] The dual-steering module controller controls the first and second steering systems to achieve the desired target steering angles, and should adopt a closed-loop control method to improve control accuracy.

[0133] The working principles of each system assembly are as follows:

[0134] Drive system: After receiving the drive signal from the driver or the decision-making unit, the inner rotor motor outputs the driving torque through the inner rotor motor output shaft. The torque is first transmitted through the drive system reducer to decelerate and increase the torque, and then output from the drive system output shaft. It is then transmitted to the hub flange through the spline, and then transmitted to the wheel hub through the bolts on the hub flange. Finally, the wheel hub transmits the driving torque to the ground through the tire, thereby driving the vehicle.

[0135] Braking system: The braking system generates a braking force after receiving a driving signal from the driver or decision-making unit, pushing the brake caliper to clamp the brake disc, forcing the brake disc to generate a braking torque. The brake disc transmits the braking torque to the wheel hub through the center hub through-hole. Finally, the wheel hub transmits the braking torque to the ground through the tire, thereby forcing the vehicle to brake.

[0136] First Steering System: The first steering motor generates a corresponding torque after receiving a control signal from the dual steering module controller. This torque is then decelerated and torque-increased by the first steering system reducer, then transmitted from the first steering system output shaft to the spline groove on the first steering knuckle. The first steering knuckle then outputs the torque to the wheel hub flange via the drive system output shaft, which then transmits it to the wheel hub via bolts, ultimately causing the tire to rotate about the first steering axis (K1). It is worth noting that when the first steering motor is not outputting torque, the self-locking characteristics of the worm gear lock the first and second steering knuckles, thereby reducing energy consumption of the first steering motor.

[0137] Second steering system: The steering rod generates corresponding displacement after receiving the control signal of the dual steering module controller, thereby driving the second steering knuckle to generate movement around the second steering axis (K2). If the first steering system is not working at this time, the first steering system and the second steering knuckle are fixedly connected as a whole to generate corresponding rotation, which is then output to the wheel hub flange through the output shaft of the drive system and then transmitted to the wheel hub through bolts, finally realizing the tire generating rotational movement around the second steering axis.

[0138] Suspension system: During driving, the tire of the wheel system is impacted by uneven road surface, which is transmitted to the inner hole of the first steering knuckle through the rim and hub flange and the hub bearing. The first steering knuckle transmits the road impact through the upper and lower support arms. The second steering knuckle then transmits the road impact through the ball pin through the upper and lower support arm ball pin seats to the upper and lower control arms. The lower control arm transmits the road impact through the upper lug and the pin shaft to the shock absorber bracket, and then passes through the spring and damper in the shock absorber spring assembly to achieve the effect of alleviating the road impact.

[0139] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A dual steering module integrating active camber and active toe, characterized in that: include: A wheel assembly (100) is used to carry vehicle loads and internally integrates a drive system and a brake system for controlling longitudinal motion of the vehicle, wherein the drive system adopts an inner rotor hub motor drive mode to reduce the outer diameter volume, and the brake system adopts a wire control brake mode; A first steering system (200) adopts a kingpin steering mode and serves as a backup system in case the main steering system fails. The system can independently adjust the wheel toe angle, and includes a first steering motor assembly and a first steering knuckle, wherein the first steering knuckle determines a first kingpin axis (K1); the first steering system cooperates with the wheel hub bearing of the wheel assembly and is fixedly connected to the drive system housing; A second steering system (300) adopts a tie rod steering form and is a main steering system, which can cooperate with the first steering system to realize active adjustment of the wheel camber angle decoupled from the wheel angle, and includes a steering tie rod and a second steering knuckle, wherein the second steering knuckle determines a second kingpin axis (K2); the second steering knuckle is connected to the first steering knuckle by a hinge and is fixedly connected to the first steering motor assembly; The suspension system (400) is an unequal length double wishbone suspension, including upper and lower control arms, a shock absorber bracket and a shock absorber spring assembly; The suspension system is connected to the second steering knuckle of the second steering system through a ball pin, so as to mitigate road impact and improve vehicle ride comfort.

2. The dual steering module integrating active camber and active toe according to claim 1, characterized in that: The first kingpin axis (K1) is characterized by: The first kingpin axis (K1) should be approximately or completely perpendicular to the wheel ground plane to ensure independent adjustment of the wheel toe. At the same time, this configuration is convenient for cooperating with the second steering system to achieve active wheel camber angle adjustment decoupled from the wheel angle.

3. The dual steering module integrating active camber and active toe according to claim 1, characterized in that: The second kingpin axis (K2) is characterized by: The second kingpin axis (K2), serving as the kingpin axis of the main steering system, should be designed with kingpin positioning parameters that first meet the vehicle's high-speed handling stability requirements, and then consider meeting the required wheel camber active adjustment range. The specific design process is as follows: S0: Start; S1: Design the initial values ​​of the kingpin positioning parameters β0, θ0 of the second kingpin axis according to the vehicle's high-speed handling stability requirements; S2: Substitute the active camber angle range calculation formula into: Where α(δ2) is the wheel camber angle change angle; β0 and θ0 are the initial design values ​​of the kingpin inclination angle and the kingpin caster angle of the second kingpin axis respectively; δ2 is the angle of the wheel turned by the second steering system for adjusting the wheel camber angle; the maximum and minimum change angles of the wheel camber angle are α max =max(α(δ2)) and α min =min(α(δ2)); S3: Determine whether the active camber angle variation range meets the design requirements. If so, execute S4. If not, return to S1 and redesign. S4: End.

4. The dual steering module integrating active camber and active toe according to claim 1, characterized in that: The wheel assembly (100) is characterized by comprising: The wheel hub (102) is divided into a rim and a spoke. The rim is ring-shaped and used to mount the tire (101). Edges are provided on both sides to prevent the tire from falling off. The spoke is composed of a plurality of spokes. An end nut through hole is provided at the center of the spoke connection. A plurality of brake disc through holes are provided around the end nut through hole. A brake disc (103) is provided with a through hole at the center and threaded holes around it, and is fixedly connected to the brake disc through hole of the wheel hub via bolts; A hub flange (104) is provided with a spline groove through hole at the center and a plurality of threaded through holes on the flange, and is connected to the hub and the brake disc by bolts; A wheel hub bearing (105) is a tapered roller bearing, mounted between the outer diameter of the wheel hub flange end and the first steering knuckle of the first steering system (200), for reducing friction loss during wheel rotation and carrying radial and axial loads during vehicle operation; A brake caliper (106) is a floating caliper type, clamped at the outer edge of the brake disc, and leaving a suitable braking gap; The drive system assembly (107) includes a drive motor and a drive system reducer. A drive system assembly output shaft is provided at the center, which is provided with splines and threads and is connected to the hub flange through splines and end nuts.

5. The wheel assembly (100) according to claim 4, characterized in that: The drive system assembly (107) is characterized in that: An inner rotor drive motor and a coaxially arranged drive system reducer are integrated internally, and the drive system reducer adopts a planetary gear reduction mechanism; the output torque of the inner rotor drive motor is decelerated by the drive system reducer and then output from the output end of the drive system reducer, i.e., the output shaft of the drive system assembly; the drive system assembly is provided with a plurality of mounting threaded holes on the wheel-side end surface, and is fixedly connected to the first steering knuckle of the first steering system (200) by screws, and moves as a whole with the deflection of the first steering knuckle.

6. The dual steering module integrating active camber and active toe according to claim 1, characterized in that: The first steering system (200) is characterized by comprising: A first steering motor assembly (201) includes a first steering motor and a first steering reducer, a lug is provided at the tail portion, and an output shaft of the first steering motor assembly is provided at the head portion, wherein the output shaft is provided with an external spline and an external thread; The first steering knuckle (202) has a main body in the shape of a circular plate, a transmission shaft through hole is provided in the center for passing the output shaft of the drive motor assembly, and drive system through holes are provided around it, which is connected to the drive motor assembly by screws, and an inner hole boss is provided on the wheel side surface, and the inner hole of the boss cooperates with the wheel hub bearing; a circular groove is provided on the body side for radial positioning and fixing the drive system of the wheel assembly (100); two "L"-shaped support arms are provided on the upper and lower surfaces, and vertical through holes are provided on the end surfaces of the upper and lower support arms respectively, and the center line of the upper and lower through holes is used to determine the first kingpin axis (K1); a spline is provided in the upper support arm through hole, which cooperates with the outer spline of the output shaft of the first steering motor assembly and is axially limited by an end nut; a pair of brake caliper lugs are provided on the front side of the first steering knuckle for installing the brake caliper.

7. The first steering system (200) according to claim 6, characterized in that The first steering motor assembly (201) is characterized in that: A first steering motor and a first steering reducer are integrated internally. The first steering motor should have good control accuracy so as to realize accurate control of the wheel angle. A lug with a through hole is provided at the rear of the first steering motor housing for fixing to the second steering knuckle of the second steering system (300); the output end of the first steering motor is spline-connected with the input end of the first steering reducer; the first steering reducer adopts a worm gear reducer, which not only ensures a larger transmission ratio and thus reduces the volume of the first steering reducer, but also ensures that the first steering system has a reverse self-locking capability and thus reduces the energy consumption of the motor at the end of the controlled movement; the output shaft of the first steering reducer is the output shaft of the first steering motor assembly, and its axis is rotated 90 degrees relative to the axis of the first steering motor, and is provided with splines and threads.

8. The dual steering module integrating active camber and active toe according to claim 6, characterized in that: The second steering system (300) is characterized by comprising: The second steering knuckle (301) is in an "E" shape as a whole, and has three support arms (upper, middle and lower) and a main arm, wherein the top surface of the lower support arm is connected to the through hole of the lower support arm of the first steering knuckle via a pin shaft, the center point of which constitutes the lower end point of the first main pin axis (K1), and the lower end surface of the lower support arm is also provided with a ball pin threaded hole; the head of the middle support arm is punched with a through hole for passing the output shaft of the first steering motor assembly, the center point of which constitutes the upper end point of the first main pin axis (K1); the top surface of the head of the upper support arm is provided with a ball pin threaded hole, which together with the ball pin threaded hole of the lower support arm determines the second steering axis (K2); the main arm is fixedly connected to the three support arms as a whole, and the upper and lower end surfaces of the connection between the main arm and the middle support arm are respectively provided with the first steering motor assembly mounting hole and the steering tie rod support arm, wherein the steering tie rod support arm is fixedly connected to the main arm as a whole, and the end thereof is provided with a ball pin mounting hole; the shape design of the second steering knuckle should avoid motion interference with other parts during wheel steering and active camber and toe angle changes; The steering rod (302) is rod-shaped as a whole, and has a ball pin support at its head, which is connected to the ball pin mounting hole of the second steering knuckle steering rod support arm through a ball pin; the steering rod can control the second steering knuckle (301) to deflect around the second steering axis (K2) under the drag of a mechanical steering transmission mechanism or an electromechanical actuator, thereby realizing a non-decoupled mechanical steering function and a decoupled wire-controlled steering function respectively.

9. The dual steering module integrating active camber and active toe according to claim 8, characterized in that: The suspension system (400) is characterized by comprising: The lower control arm (401) is generally A-shaped and has two cross swing arms and a transverse arm. A ball pin support is provided at the intersection of the swing arms and is connected to the ball pin hole of the second steering knuckle lower support arm via a ball pin. The center of the ball pin constitutes the lower end point of the second kingpin axis (K2). The tails of the two swing arms are each provided with a boss through-hole for connecting to the vehicle body or subframe via a hinge. A shock absorber lug is provided in the middle of the transverse arm. The shock absorber bracket (402) has a shock absorber mounting hole on the top and a threaded lug for adjusting the diameter of the mounting hole; two arc-shaped support arms are provided at the bottom, and a lower control arm lug is provided at the bottom of the support arm and is connected to the lower control arm shock absorber lug via a pin shaft; The damping spring assembly (403) has a shock absorber and a coil spring integrated therein, and the two are coaxially arranged; a lug is provided on the top and connected to the vehicle body or subframe via a pin; a support rod is provided on the bottom and is installed in the mounting hole of the shock absorber bracket; the shock absorber can be a passive hydraulic shock absorber, an adjustable damping shock absorber, or even an electric shock absorber for active suspension; The upper control arm (404) is composed of two crossed swing arms. A ball pin support is provided at the intersection of the swing arms and is connected to the ball pin hole of the second steering knuckle upper support arm through a ball pin. The center point of the ball pin constitutes the upper end point of the second kingpin axis (K2). The tails of the two swing arms are both provided with a boss through hole for connecting to the vehicle body or subframe through a hinge. It should be ensured that there is no motion interference with the shock absorbing spring assembly during vehicle operation.

10. The dual steering module integrating active camber and active toe according to claim 1, characterized in that: The control method of the dual-steering module includes: S0: Start; S1: The dual steering module controller receives a command signal from the upper computing unit to adjust the wheel camber angle, adjust the wheel toe, or perform wheel steering movement; S2: The dual-steering module controller reads the kingpin positioning parameters β and γ of the second steering system of the vehicle from the storage unit, where β is the kingpin inclination angle and γ is the kingpin caster angle; S3: The dual steering module controller analyzes the command signal and determines the current steering mode of the vehicle. If it is the normal steering mode, S4 is executed; if it is the steering fault tolerance mode, S8 is executed. S4: The dual steering module controller analyzes the command signal to determine whether to enter the active camber mode. If the active camber mode is entered, S5 is executed; otherwise, S6 is executed. S5: The dual steering module controller calculates the wheel adjustment angle δ for the vehicle to change the wheel camber angle through formula 1 c , and execute S7; S6: The dual-steering module controller calculates the target turning angles δ1 and δ2 of the first and second steering systems using Formula 2, and executes S9; S7: The dual-steering module controller calculates the target turning angles δ1 and δ2 of the first and second steering systems using Formula 3, and executes S9; S8: The dual-steering module controller calculates the target turning angles δ1 and δ2 of the first and second steering systems using Formula 4, and executes S9; S9: The dual steering module controller controls the first and second steering systems to achieve the desired target steering angles δ1 and δ2; S10: End; The normal steering mode is when there is no steering system fault signal, the vehicle can steer through the second steering system, which is the main steering system. The steering fault-tolerant mode is when a fault signal from the second steering system is received, the vehicle cannot continue to steer through the second steering system, and can only steer through the first steering system. Therefore, the active camber mode cannot be entered at this time. At this time, the first steering system becomes the backup steering system, ensuring that the vehicle still has the steering capability in the event of a main steering system failure, thereby ensuring the safety of the steer-by-wire function. The active camber mode is determined by determining whether the desired camber angle α is zero. If it is zero, the active camber mode is not entered, and in this mode, the second steering system is the main steering system, and the first steering system is only used for adjusting the wheel toe angle. If it is not zero, the active camber mode is entered, and the first and second steering systems cooperate with each other to achieve controllable adjustment of the wheel camber angle without changing the wheel deflection angle or toe angle. Wherein the formula 1 is: in This formula is used to calculate the wheel adjustment angle δ for wheel camber change c ; Formula 2 is: where δ t ,δ w are the desired toe angle and the desired wheel turning angle of the vehicle respectively; the formula 3 is: The formula 4 is: Due to the presence of the kingpin alignment parameter of the second steering system, the wheel camber angle will also change during the vehicle's conventional steering process. However, unlike the decoupling control of the wheel camber angle and wheel steering angle in the active camber mode, the wheel camber angle and wheel steering angle in the conventional steering process have an inherent coupling relationship common to all current suspension systems. The dual steering module controller should adopt a closed-loop control method to control the first and second steering systems to achieve the desired target turning angles to improve control accuracy.

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