Coordinated control system and method for drive-by-wire chassis of hovercar

Abstract

The invention discloses a hovercar drive-by-wire chassis coordination control system and method, and belongs to the field of vehicle control. The upper layer is a target layer and is responsible for receiving driver intention and current vehicle body state parameters, processing the driver intention and the current vehicle body state parameters, judging current vehicle body postures and providing a basis for follow-up coordination control; the middle layer is a coordination layer and comprises a steer-by-wire system, a driving system, a suspension system controller and a coordination controller, after a control signal from the target layer is received, each subsystem controller firstly controls a corresponding target, and then the coordination controller adjusts each subsystem controller in combination with the vehicle condition; mutual interference is eliminated while efficient operation of the subsystems is guaranteed, and overall optimization of chassis performance is achieved; and the bottom layer is an execution layer which is responsible for executing a control target of the coordination layer, collecting an execution result in real time and feeding back the execution result to the coordination controller to form closed-loop control. According to the invention, the subsystems of the chassis are linked through the coordination controller, so that the comprehensive performance of the flying car during running is improved.

Description

Technical Field

[0001] This invention belongs to the field of vehicle control technology, specifically relating to a coordinated control system and method for a fly-by-wire chassis of a flying car. Background Technology

[0002] With the rapid iteration of science and technology, flying cars, as a new type of transportation that combines the characteristics of aircraft and automobiles, have gradually become a research hotspot in the field of transportation. In the technological system of flying cars, drive-by-wire chassis technology is crucial, directly affecting the driving performance and safety of the flying car. During actual operation, the various subsystems of the chassis interact and influence each other, thus requiring a coordinating controller to perform overall adjustments to each subsystem.

[0003] Among existing chassis coordination control methods, distributed control has low complexity but suffers from information silos; centralized control ensures global control optimality but lacks system flexibility and fault redundancy design. Hierarchical chassis coordination control, however, strikes a balance between the low complexity of distributed control and the global optimization of centralized control, reducing systemic risks through hierarchical isolation. This, in turn, improves the driving performance of flying cars under complex conditions. Summary of the Invention

[0004] This invention addresses the shortcomings of existing research by providing a coordinated control system and method for a flight car's drive-by-wire chassis.

[0005] To solve the above problems, the present invention adopts the following technical solution:

[0006] A flight car drive-by-wire chassis coordination control system mainly includes:

[0007] Step 1. Target Layer: Responsible for receiving the driver's intentions and current vehicle status parameters, processing them, and determining the current vehicle posture to provide a basis for subsequent coordinated control.

[0008] Step 2. Coordination Layer: This includes the steer-by-wire system, drive system, suspension system controller, and coordination controller. After receiving control signals from the target layer, each subsystem controller first controls its corresponding target. Then, the coordination controller adjusts each subsystem controller based on the vehicle's condition. This ensures efficient operation of each subsystem while eliminating mutual interference and achieving optimal overall chassis performance.

[0009] Step 3. Execution Layer: Responsible for executing the control objectives of the coordination layer, collecting execution results in real time and feeding them back to the coordination controller to form a closed-loop control.

[0010] Furthermore, in Step 1, the driver's intention is directly reflected through physical operation, including the steering wheel angle and accelerator pedal opening, and is obtained through the steering wheel angle sensor and the accelerator pedal opening sensor.

[0011] Furthermore, in Step 1, the current vehicle body state parameters are provided by vehicle sensors, including: speed sensor, angle sensor, angular velocity sensor, wheel speed sensor, and environmental parameter sensor.

[0012] Furthermore, in Step 1, the raw signal collected by the sensor will be processed by Kalman filtering to remove interference such as road bumps and operation vibrations, and then transmitted to the corresponding subsystem controller via the CAN bus.

[0013] Furthermore, in Step 2, when the steer-by-wire system, drive system, and suspension system controllers receive the control signal from the upper layer, they first process the signal in conjunction with their respective control strategies. Moreover, each subsystem controller ignores the influence of other subsystems during its design, thereby reducing modeling difficulty and controller order. The control objective of the steer-by-wire system is the steering system transmission ratio, the control objective of the drive system is the driving torque of the front and rear axles, and the control objective of the suspension system is the variable damping force of the four suspensions.

[0014] Furthermore, in Step 1, the vehicle controller analyzes the vehicle pitch angle θ and pitch velocity. roll angle φ, roll rate This allows the system to determine the current vehicle posture and exchange data with the coordination controller in real time via the CAN bus.

[0015] Furthermore, in Step 2, the coordination controller dynamically corrects the control objectives of each subsystem based on the current vehicle body posture, eliminating conflicts when the subsystems are controlled independently.

[0016] Furthermore, in Step 3, the steer-by-wire system, drive system, and suspension system in the execution layer are responsible for executing the control objectives of the coordination layer.

[0017] Furthermore, in Step 3, the execution layer incorporates a steering angle sensor, a torque sensor, and a displacement sensor to collect execution results in real time and feed them back to the coordination controller, forming a closed-loop control.

[0018] Compared with the prior art, the beneficial effects of this invention are as follows:

[0019] 1. A hierarchical chassis coordination control architecture is adopted, which allows each subsystem controller to handle control objectives independently, ignoring cross-influences to reduce modeling difficulty and controller order. At the same time, the coordination controller adjusts each subsystem in conjunction with the vehicle body attitude, achieving a balance between distributed and centralized architecture.

[0020] 2. By coordinating the unified adjustment of the controller, the problem of "information silos" that may exist in distributed control is solved, enabling subsystems such as steer-by-wire, drive, and suspension to work independently while forming an organic synergy, thereby improving the overall control effect of the chassis system.

[0021] 3. The controllers of each subsystem ignore the influence of other subsystems during the design process, which reduces the modeling difficulty and controller order. This helps to speed up the response of each subsystem and enable control commands to be executed more quickly.

[0022] 4. The coordination controller can dynamically adjust the control objectives of each subsystem according to the real-time attitude of the vehicle body, and can respond to changes in vehicle body attitude in a targeted manner, reduce unstable factors during driving, and thus improve the driving performance of the flying car under complex working conditions. Attached Figure Description

[0023] The present invention will now be described in further detail with reference to the accompanying drawings.

[0024] Figure 1 This is a flowchart of the present invention.

[0025] Figure 2 This refers to the coordination control rules of the present invention. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] like Figure 1 As shown, the flying car's drive-by-wire chassis coordination control system includes a chassis drive-by-wire steering system, a drive system, and a suspension system; the coordination control method adopts a layered architecture, including a target layer, a coordination layer, and an execution layer.

[0028] Step 1. Target Layer: Responsible for receiving the driver's intentions and current vehicle status parameters, processing them, and determining the current vehicle posture to provide a basis for subsequent coordinated control.

[0029] Specifically, the target layer is mainly responsible for collecting and processing driver intentions and vehicle state parameters. Driver intentions are obtained through physical manipulation; vehicle state parameters are provided collaboratively by multiple types of vehicle sensors, covering motion, posture, and environmental stimulus dimensions. The sensor includes: Speed ​​sensor: Used to collect the vehicle speed u of the flying car. Angle sensor: used to collect the steering wheel angle δ, roll angle φ, and pitch angle θ of the flying car. Angular velocity sensor: used to collect the roll angular velocity of flying cars Pitch angular velocity Wheel speed sensor: Used to collect the wheel speed ω of the flying car. Throttle pedal opening sensor: Used to collect the throttle pedal opening K of the flying car. Environmental parameter sensor: Used to collect environmental parameters of the flying car.

[0030] The original sensor signal is processed by a Kalman filter and then transmitted to the corresponding subsystem controller via the CAN bus to eliminate interference such as operational jitter and ensure the stability of the intended signal.

[0031] Step 2. Coordination Layer: This includes the steer-by-wire system, drive system, suspension system controller, and coordination controller. After receiving control signals from the target layer, each subsystem controller first controls its corresponding target. Then, the coordination controller adjusts each subsystem controller based on the vehicle's condition. This ensures efficient operation of each subsystem while eliminating mutual interference and achieving optimal overall chassis performance.

[0032] Specifically, when the steer-by-wire system, drive system, and suspension system controllers receive control signals from the upper layer, they first process the signals in conjunction with their respective control strategies. Furthermore, each subsystem controller ignores the influence of other subsystems during the design process, thereby reducing the modeling difficulty and the controller order.

[0033] The control objective of a steer-by-wire system is the steering system's gear ratio, and includes the following steps:

[0034] Different gear ratios are set according to different vehicle speeds to improve the steering agility of the flying car at low speeds and its steering stability at high speeds.

[0035]

[0036] Where i is the transmission ratio of the flying car, L is the wheelbase, K is the vehicle stability factor, and G... sw For the yaw rate gain, i min For the minimum transmission ratio, i maxFor the maximum transmission ratio, u min For the minimum vehicle speed, u max Maximum speed.

[0037] The drive system controls the driving torque of the front and rear axles, and includes the following steps:

[0038] The maximum slip ratio threshold is set to 0.2. When the maximum slip ratio of the front and rear axles exceeds 0.2, the anti-slip controller is activated to limit the slip ratio by restricting the output torque of the front and rear axle motors.

[0039] The controller's control rules stipulate that if the slip ratio of either the current or rear axle exceeds 0.2, the output torque of that axle is limited. Simultaneously, to meet the driving requirements of the flying car, the output torque of the other axle should be appropriately increased. If the slip ratios of both axles exceed 0.2, the output torque of both axles is limited simultaneously to ensure the flying car's stability and safety. Furthermore, a special case needs to be considered: when the vehicle is stationary, the tire angular velocity is 0, and the denominator of the slip ratio calculation formula is 0; therefore, the slip ratio should also be set to 0 at this time. Additionally, considering that using only 0.2 as the controller's on / off threshold would lead to frequent controller switching and thus deteriorate the control effect, a minimum slip ratio threshold of 0 is added. That is, when the slip ratio exceeds 0.2, the controller is activated; when the slip ratio is less than 0, the controller is deactivated, thereby solving the problem of frequent controller start-stop.

[0040] The suspension system control objective is the variable damping force of the four suspensions, including the following steps:

[0041] This invention uses an ideal ceiling damping model as a reference to design a semi-active suspension controller for a flying car, thereby adjusting the variable damping force of the suspension system. The dynamic model equation of the ideal ceiling damping model is as follows:

[0042]

[0043] Where, m s For the sprung mass; z sr The displacement of the spring-loaded mass; m u Unsprung mass; z ur For unsprung mass displacement; K s For suspension stiffness; K t For tire stiffness; C s0 C is the passive suspension damping coefficient. sky The damping coefficient is the constant. For the speed of the sprung mass; The acceleration of the sprung mass; The velocity is the velocity of the unsprung mass. For unsprung mass acceleration; z g This is a random road surface excitation based on the filtered white noise method.

[0044] Specifically, the coordination controller adjusts the controllers of each subsystem based on the vehicle's condition.

[0045] like Figure 2 As shown, in the control strategies of each subsystem, interfaces related to tire dynamic loads in the suspension system are reserved in advance. These tire dynamic loads are simultaneously used as inputs to the drive and steer-by-wire systems, thereby adjusting their outputs and linking the flying car chassis suspension, drive, and steer-by-wire systems. To stabilize the vehicle's attitude, suppress pitch motion, and reduce the risk of instability, this invention uses the vehicle pitch angle θ and pitch angular velocity... roll angle φ and roll rate As input to the coordinated control system, the output is the variable damping force correction value ΔF for the four suspensions. i (where i = 1, 2, 3, 4 represent left front, right front, left rear, and right rear), thereby adjusting the tire dynamic load output by the semi-active suspension system, and then controlling the drive and steer-by-wire systems through relevant interfaces to achieve coordination between the various subsystems of the flying car chassis.

[0046] When θ > 0 and When the flying car "nods" and the angle tends to increase, adjustments should be made to ΔF1, ΔF2 < 0 and ΔF3, ΔF4 > 0 to counteract the change. The correction values ​​are related to the vehicle's pitch angle θ and pitch velocity. There is a positive correlation, which causes the vehicle body angle to tend to decrease; when θ < 0 and When the flying car "lifts up" and the angle tends to increase, ΔF1, ΔF2 > 0 and ΔF3, ΔF4 < 0 should be adjusted to counteract the change. The correction value of the damping force is related to the vehicle's pitch angle θ and pitch velocity. The correlation is negative, and the variable damping force correction value ΔF of the four suspensions is adjusted. i This reduces the vehicle pitch angle θ and the vehicle pitch rate. The absolute value of the value helps maintain the stability of the vehicle's posture.

[0047] When θ > 0 and When the flying car "nods" and the angle tends to decrease, adjustments should be made to ΔF1, ΔF2 < 0 and ΔF3, ΔF4 > 0 to counteract the change and prevent the trend of the vehicle angle decreasing too much. The correction value is positively correlated with the vehicle pitch angle θ, but not with the vehicle pitch rate. Negative correlation; when θ < 0 and When the flying car "raises up" and the angle tends to decrease, ΔF1, ΔF2 > 0 and ΔF3, ΔF4 < 0 should be adjusted to counteract the change. The correction value is negatively correlated with the vehicle's pitch angle θ, but not with the vehicle's pitch rate. The correlation is positive, and the correction value ΔF of the variable damping force of the four suspensions is adjusted.i This reduces the vehicle pitch angle θ and the vehicle pitch rate. The absolute value of the value helps maintain the stability of the vehicle's posture.

[0048] When φ>0 and When the flying car tilts to the left with an increasing angle, adjustments should be made to ΔF1, ΔF3 < 0 and ΔF2, ΔF4 > 0 to counteract the change. The correction values ​​are related to the vehicle's roll angle φ and roll rate. There is a positive correlation, which causes the body angle to tend to decrease; when φ < 0 and When the flying car tilts to the right with an increasing angle, adjustments should be made to ΔF1, ΔF3 > 0 and ΔF2, ΔF4 < 0 to counteract the change. The correction values ​​are related to the vehicle's roll angle φ and roll rate. The correlation is negative, and the variable damping force correction value ΔF of the four suspensions is adjusted. i This reduces the roll angle φ and roll rate. The absolute value of the value helps maintain the stability of the vehicle's posture.

[0049] When φ>0 and When the flying car tilts to the left and the angle tends to decrease, adjustments should be made to ΔF1, ΔF3 < 0 and ΔF2, ΔF4 > 0 to counteract the change and prevent the trend of the car angle decreasing too much. The correction value is positively correlated with the car's roll angle φ, but not with the car's roll rate. Negative correlation; when φ < 0 and When the flying car tilts to the right with a decreasing angle, adjustments should be made to ΔF1, ΔF3 > 0 and ΔF2, ΔF4 < 0 to counteract the change. The correction value is negatively correlated with the vehicle's roll angle φ, but not with the vehicle's roll rate. The correlation is positive, and the correction value ΔF of the variable damping force of the four suspensions is adjusted. i This reduces the roll angle φ and roll rate. The absolute value of the value helps maintain the stability of the vehicle's posture.

[0050] Considering the complex coupling relationships between subsystems and the excessive complexity of establishing control equations, this invention employs fuzzy control to control the vehicle's pitch angle θ and pitch velocity. roll angle φ and roll rate The process is then performed. The basic universe of discourse for the above four parameters is defined as [-3,3]. The output is the variable damping force correction value, with a basic universe of discourse of [-6,6]. The magnitude of each parameter is adjusted by a scaling factor.

[0051] Step 3. Execution Layer: Responsible for executing the control objectives of the coordination layer, collecting execution results in real time and feeding them back to the coordination controller to form a closed-loop control.

[0052] Specifically, the execution layer, as the system's execution terminal, consists of the execution components of the steer-by-wire system, drive system, and suspension system, and is responsible for converting the control objectives output by the coordination layer into physical actions.

[0053] The steer-by-wire system adjusts the steering wheel angle through the steering actuator to accurately track the transmission ratio target of the coordination layer; the drive system outputs the front and rear axle drive torques distributed by the coordination layer through the front and rear axle drive motor actuators; the suspension system adjusts the damping force in real time through the magnetorheological damper to respond to the control commands of the coordination layer.

[0054] This invention aims to achieve efficient collaborative operation of various subsystems of a flying car chassis through a hierarchical control architecture, thereby improving driving performance and safety under complex operating conditions.

Claims

1. A flycar drive-by-wire chassis coordinated control system, characterized in that include: Step 1. Target Layer: Responsible for receiving the driver's intentions and current vehicle status parameters, and determining the current vehicle attitude; Step 2. Coordination Layer: This includes the steer-by-wire system, drive system, suspension system controller, and coordination controller. After receiving control signals from the target layer, each subsystem controller first controls its corresponding target. Then, the coordination controller adjusts each subsystem controller based on the vehicle's condition. This ensures efficient operation of each subsystem while eliminating mutual interference and achieving optimal overall chassis performance. Step 3. Execution Layer: Responsible for executing the control objectives of the coordination layer, collecting execution results in real time and feeding them back to the coordination controller to form a closed-loop control.

2. The coordinated control system of a flying car drive-by-wire chassis according to claim 1, characterized in that: The driver's intention is directly reflected through physical operations, including steering wheel angle and accelerator pedal opening, and is measured by steering wheel angle sensor and accelerator pedal opening sensor; The current vehicle body status parameters are provided by vehicle sensors, including: speed sensor, angle sensor, angular velocity sensor, wheel speed sensor, and environmental parameter sensor.

3. The coordinated control system of a flying car drive-by-wire chassis according to claim 1, characterized in that: The raw signals collected by the sensors are processed by Kalman filtering to remove road bumps and operational jitter, and then transmitted to the corresponding subsystem controller via the CAN bus.

4. The flight car drive-by-wire chassis coordination control system according to claim 2, characterized in that: When the controllers of the steer-by-wire system, drive system, and suspension system receive control signals from the upper level, they first process the signals in combination with their respective control strategies, and each subsystem controller ignores the influence of other subsystems during the design process. The control target of the steer-by-wire system is the steering system transmission ratio, the control target of the drive system is the front and rear axle drive torque, and the control target of the suspension system is the variable damping force.

5. The flight car drive-by-wire chassis coordination control system according to claim 2, characterized in that: The vehicle controller analyzes the vehicle's pitch angle θ and pitch rate. roll angle φ, roll rate This allows the system to determine the current vehicle posture and exchange data with the coordination controller in real time via the CAN bus.

6. The method using the system as described in claim 1, characterized in that: Step 1. Target Layer: Responsible for receiving the driver's intentions and current vehicle status parameters, processing them, and determining the current vehicle attitude to provide a basis for subsequent coordinated control; The driver's intent is obtained through physical manipulation; the vehicle's state parameters are provided collaboratively by multiple types of vehicle sensors, covering the dimensions of motion, attitude, and environmental stimulus. The sensor includes: Speed ​​sensor: used to collect the vehicle speed u of the flying car; Angle sensor: used to collect the steering wheel angle δ, roll angle φ, and pitch angle θ of the flying car; Angular velocity sensor: used to collect the roll angular velocity of flying cars Pitch angular velocity Wheel speed sensor: used to collect the wheel speed ω of the flying car; Throttle pedal opening sensor: used to collect the throttle pedal opening K of the flying car; Environmental parameter sensors: used to collect environmental parameters of the flying car; The original sensor signal is processed by a Kalman filter and then transmitted to the corresponding subsystem controller via the CAN bus to eliminate operational jitter. Step 2. Coordination Layer: This includes the steer-by-wire system, drive system, suspension system controller, and coordination controller. After receiving control signals from the target layer, each subsystem controller first controls the corresponding target, and then the coordination controller adjusts each subsystem controller based on the vehicle condition. Specifically, the steer-by-wire system, drive system, and suspension system controllers process the control signals received from the upper level.

7. The method according to claim 6, characterized in that: The control objective of a steer-by-wire system is the steering system gear ratio, and includes the following steps: Different gear ratios are set according to different vehicle speeds to improve the steering agility of the flying car at low speeds and the steering stability at high speeds. where i is the transmission ratio of the flying car, L is the wheel base, K is the stability factor of the car, G sw is the yaw rate gain, i min is the minimum value of the transmission ratio, i max is the maximum value of the transmission ratio, u min is the minimum vehicle speed, u max is the maximum vehicle speed.

8. The method according to claim 6, characterized in that: The drive system controls the driving torque of the front and rear axles, and includes the following steps: The maximum slip ratio threshold is set to 0.

2. When the maximum slip ratio of the front and rear axles exceeds 0.2, the anti-slip controller is activated to limit the slip ratio by restricting the output torque of the front and rear axle motors. The controller's control rules stipulate that if the slip ratio of either the current or rear axle exceeds 0.2, the output torque of that axle is limited. Simultaneously, to meet the driving requirements of the flying car, the output torque of the other axle should be appropriately increased. If the slip ratios of both axles exceed 0.2, the output torque of both axles is limited simultaneously. Furthermore, a special case needs to be considered: when the vehicle is stationary, the tire angular velocity is 0, and the denominator of the slip ratio calculation formula is 0; therefore, the slip ratio should also be set to 0 at this time. In addition, considering that using only 0.2 as the controller's on / off threshold would lead to frequent controller switching and thus deteriorate the control effect, a minimum slip ratio threshold of 0 is added. That is, when the slip ratio exceeds 0.2, the controller is activated; when the slip ratio is less than 0, the controller is deactivated, thereby solving the problem of frequent controller start-stop.

9. The method according to claim 7, characterized in that: The suspension system control objective is the variable damping force of the four suspensions, including the following steps: Taking the ideal ceiling damping model as a reference, the dynamic model equation of the ideal ceiling damping model is: Where, m s For the sprung mass; z sr The displacement of the spring-loaded mass; m u Unsprung mass; z ur For unsprung mass displacement; K s For suspension stiffness; K t For tire stiffness; C s0 C is the passive suspension damping coefficient. sky The damping coefficient is the constant. For the speed of the sprung mass; The acceleration of the sprung mass; The velocity is the velocity of the unsprung mass. For unsprung mass acceleration; z g For road surface excitation; The coordination controller adjusts the controllers of each subsystem based on the vehicle's condition.

10. The method according to claim 7, characterized in that: With vehicle pitch angle θ and pitch angular velocity roll angle φ and roll rate As input to the coordinated control system, the output is the variable damping force correction value ΔF for the four suspensions. i Where i = 1, 2, 3, 4 represent left front, right front, left rear, and right rear, respectively, in order to adjust the tire dynamic load output by the semi-active suspension system, and then control the drive and steer-by-wire systems through relevant interfaces to achieve coordination between the various subsystems of the flying car chassis. When θ > 0 and When the flying car "nods" and the angle tends to increase, ΔF1, ΔF2 < 0 and ΔF3, ΔF4 > 0 should be adjusted to counteract the change; when θ < 0 and When the flying car "raises up" and the angle tends to increase, ΔF1, ΔF2 > 0 and ΔF3, ΔF4 < 0 should be adjusted to counteract the change. When θ > 0 and When the flying car "nods" and the angle tends to decrease, adjustments should be made to ΔF1, ΔF3 < 0 and ΔF2, ΔF4 > 0 to counteract the change; when θ < 0 and When the flying car "raises up" and the angle tends to decrease, ΔF1, ΔF3 > 0 and ΔF2, ΔF4 < 0 should be adjusted to counteract the change; When φ>0 and When the flying car tilts to the left and the angle tends to increase, ΔF1, ΔF3 < 0 and ΔF2, ΔF4 > 0 should be adjusted to counteract the change; when φ < 0 and When the flying car tilts to the right and the angle tends to increase, ΔF1, ΔF3 > 0 and ΔF2, ΔF4 < 0 should be adjusted to counteract the change. When φ>0 and When the flying car tilts to the left and the angle tends to decrease, ΔF1, ΔF3 < 0 and ΔF2, ΔF4 > 0 should be adjusted to counteract the change; when φ < 0 and When the flying car tilts to the right and the angle tends to decrease, ΔF1, ΔF3 > 0 and ΔF2, ΔF4 < 0 should be adjusted to counteract the change.

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