Suspension control method and system based on wheel rotation signal, and vehicle

Abstract

A control method and system for adjusting suspension damping on the basis of a wheel speed sensor signal. Vehicle wheel vibration caused by road surface excitation is sensed by means of a wheel speed sensor signal, and a sensed wheel vibration signal is used for adjusting and controlling suspension damping, etc. Therefore, a ubiquitous wheel speed sensor on a vehicle can be used to replace an unsprung mass acceleration sensor required in an electronically controlled shock absorber solution in the industry, to acquire data to sense unsprung mass motion information of the vehicle, so as to adjust and control suspension damping, etc., thereby reducing design and manufacturing costs and reducing the system assembly difficulty.

Description

A suspension control method, system, and vehicle based on wheel rotation signals. Technical Field

[0001] This invention relates to the field of suspension system control, and in particular to an electronically controlled suspension control method, system, and vehicle based on wheel rotation signals. Background Technology

[0002] In existing technologies, semi-active suspension damping adjustment in vehicles typically requires signals based on wheel vertical vibration. Generally, wheel vertical vibration is measured using an unsprung acceleration sensor to directly measure the wheel's vertical acceleration. However, using an unsprung acceleration sensor incurs corresponding hardware costs.

[0003] To accurately measure vehicle speed, wheel speed sensors are typically installed to measure the rotational speed of the wheels. Since the vertical acceleration and angular acceleration of the wheel are both motion parameters of the wheel, and both characterize the state of the wheel or unsprung mass, when the wheel is excited by an uneven road surface, both the vertical acceleration and the angular acceleration change simultaneously. By extracting the characteristics of the change in angular acceleration, the unevenness of the road surface and the degree of excitation exerted on the wheel can be identified. This eliminates the need for an unsprung acceleration sensor, avoiding increased vehicle manufacturing costs and assembly complexity. Currently, there is no solution in the technology that eliminates the need for an unsprung acceleration sensor. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and propose a suspension control method based on wheel rotation signals to sense unsprung vibrations in a vehicle and then control the suspension damping force. This method can replace the unsprung acceleration sensor with a wheel speed sensor commonly found in vehicles. Eliminating the unsprung acceleration sensor reduces manufacturing costs and simplifies system assembly.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A suspension control method based on wheel rotation signals senses wheel vibrations caused by road surface excitation through signals indicating the wheel rotation direction, and uses the sensed wheel vibration signals for suspension adjustment and control.

[0007] The signals indicating the direction of wheel rotation include one or a combination of rotation angle, angular velocity, angular acceleration, and one or more derivatives of angular acceleration.

[0008] When the excitation from the road surface to the wheels changes, the signal indicating the wheel's rotation direction changes. Upon receiving this changed signal, the controller can adjust the suspension according to the vehicle's tuning needs. Suspension adjustment control includes one or a combination of suspension damping adjustment, suspension stiffness adjustment, and suspension active force adjustment.

[0009] The signal of the wheel rotation direction, after being converted through the wheel radius, can be equivalent to the wheel's displacement, velocity, acceleration, and one or more derivatives of the acceleration in the direction of travel.

[0010] The vehicle obtains unsprung motion information by collecting signals of wheel rotation direction from onboard wheel speed sensors. The vehicle's sprung motion signals are then detected by one or more of the following: gyroscope, sprung acceleration sensor, or vehicle height sensor. Based on the vehicle's sprung and unsprung motion information, the controller calculates the damping force, stiffness, or active force required by the vehicle.

[0011] The unsprung motion information of the vehicle is obtained by comprehensively calculating the rotation signals of four wheels; or by comprehensively calculating the unsprung motion information of the vehicle using one or more wheel rotation signals in conjunction with one or more unsprung vibration signals.

[0012] The control system includes a controller, wheel speed sensors, and sprung sensors. The wheel speed sensors are used to collect signals of the wheel rotation direction, and their output is connected to the controller. The sprung sensors are used to sense the sprung motion signals of the vehicle, and their output is connected to the controller. The controller senses unsprung motion information based on the wheel rotation direction signals. The controller calculates the damping force, stiffness, or active force required by the vehicle based on the unsprung and sprung motion information and performs damping adjustment control on the suspension.

[0013] The sprung sensor includes one or any combination of a gyroscope, a sprung accelerometer, or a vehicle height sensor, used to sense one or more sprung motion signals of the sensing vehicle.

[0014] The on-spring sensor is connected to the controller via CAN / flexray / LIN or hardwire to upload the collected information to the controller.

[0015] Preferably, the gyroscope is a 6-DOF gyroscope or a 3-DOF gyroscope.

[0016] The control system further includes: an electronically controlled damper, used to provide different damping forces to the suspension system according to the current control current and the damper speed; and an electronically controlled damper current drive module, used to enable the controller to output current to the electronically controlled damper.

[0017] A vehicle comprising the aforementioned suspension control system based on wheel rotation signals or using the aforementioned suspension control method based on wheel rotation signals for suspension control adjustment.

[0018] The advantages of this invention are: by replacing the acceleration sensor signal with the wheel speed sensor signal, the acceleration sensor is saved, thereby reducing the overall vehicle manufacturing cost and simplifying manufacturing and assembly. The unsprung acceleration sensor in the semi-active suspension system is eliminated, and the wheel speed sensor of the electronically controlled braking system is reused, using the wheel speed sensor signal to replace the unsprung acceleration sensor signal, thus saving overall vehicle manufacturing costs, simplifying the manufacturing process, and saving interior space. Attached Figure Description

[0019] The following is a brief explanation of the contents of each of the accompanying drawings and the markings in the drawings:

[0020] Figure 1 is a schematic diagram of the vehicle control system in Embodiment 1 of the present invention;

[0021] Figure 2 is a schematic diagram of the vehicle control system in Embodiment 2 of the present invention;

[0022] Figure 3 is a schematic diagram of the vehicle control system in Embodiment 3 of the present invention;

[0023] Figure 4 is a schematic diagram of the vehicle control system in Embodiment 4 of the present invention;

[0024] Figure 5 is a schematic diagram of the vehicle structure of the present invention;

[0025] Figure 6 is a flowchart illustrating the principle of the present invention for determining whether a vehicle passes over a speed bump in the vertical direction based on wheel speed sensor data.

[0026] Figure 7 is a schematic diagram of the wheel principle corresponding to the vertical motion calculation of the wheel in this invention.

[0027] The labels in the above diagrams are as follows: 1. Vehicle; 10. Controller; 101. Wheel speed sensor; 102. Wheel speed sensor interface module; 103. Microcontroller; 104. Electronically controlled shock absorber current drive module; 105. Gyroscope (six degrees of freedom); 106. Gyroscope interface module; 107. Battery; 108. Power management module; 109. Electronically controlled shock absorber; 110. Sprout acceleration sensor; 111. Acceleration sensor interface module; 112. Vehicle body high-speed sensor; 113. Vehicle body height sensor interface module. Detailed Implementation

[0028] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and the description of the preferred embodiments.

[0029] This patent proposes a method for applying wheel rotation signals to suspension control, which eliminates the unsprung acceleration sensor in the semi-active suspension system, reuses the wheel speed sensor of the electric braking system, and uses the wheel speed sensor signal to replace the unsprung acceleration sensor signal, thereby saving vehicle manufacturing costs, simplifying the manufacturing process, and saving interior space.

[0030] In existing technologies, suspension adjustment and control require unsprung motion information. This information can be acquired by adding an unsprung acceleration sensor; however, adding such a sensor increases costs and creates difficulties in production and assembly. Therefore, this solution proposes a method that utilizes wheel speed sensor signals to obtain unsprung motion information for suspension damping adjustment and control. The specific solution is as follows:

[0031] An electronically controlled suspension control method reuses onboard wheel speed sensors to collect signals indicating the wheel rotation direction. These signals are used to sense the excitation exerted on the wheels by uneven road surfaces, replacing conventional vertical acceleration / displacement sensors for electronically controlled suspension control. The wheel rotation direction signals collected by the wheel speed sensors include one or more of the following: rotation angle, angular velocity, angular acceleration, and the derivative of angular acceleration.

[0032] In this embodiment, since the vehicle needs to convert wheel speed signals into vehicle speed signals, almost every vehicle is equipped with wheel speed sensors. Therefore, this solution reuses wheel speed sensors without incurring hardware costs, and also reduces the hardware cost of unsprung acceleration sensors, achieving cost savings and saving one component per wheel. In this solution, when the vehicle travels over uneven road surfaces, the wheels will experience vertical vibration. At this time, the signal indicating the wheel rotation direction will also change accordingly. The electronically controlled suspension control method proposed in this invention can sense the excitation of the uneven road surface on the wheel (unsprung mass) based on the change in the wheel rotation direction signal, and then control the damping, stiffness, or active force of the suspension. The vertical vibration of the wheel is the unsprung vibration information. The suspension controller can realize the damping control of the suspension based on the unsprung vibration information and the collected sprung vibration information.

[0033] As shown in Figure 6, the first, second, and third conditions represent the speed bump characteristic thresholds corresponding to wheel angular velocity, wheel angular acceleration, and the differential value of wheel angular acceleration, respectively. Taking the determination of whether a vehicle has passed a speed bump as an example, the value of the vehicle's wheel speed sensor is first checked. If the wheel speed value meets the speed bump characteristic threshold, the rate of change of the wheel speed sensor signal is then checked. If the rate of change of the wheel speed sensor signal meets the speed bump characteristic threshold, the acceleration of the wheel speed sensor signal is then checked. If the acceleration of the wheel speed sensor signal meets the speed bump characteristic threshold, it is considered that the vehicle has passed the speed bump, and the speed bump control algorithm is immediately activated for the shock absorber: first, the minimum damping force is maintained to mitigate the impact when the wheel just touches the speed bump, and then the damping force is increased to reduce the vibration when the wheel lands after crossing the speed bump. Other road surface features are identified and judged in a similar manner.

[0034] Furthermore, the vertical motion of the wheel can also be calculated and calibrated using signals based on the wheel's rotation direction.

[0035] As shown in Figure 7, taking a vehicle driving over a speed bump as an example, when the tires pass over the speed bump, their horizontal direction is: F x =Fsinθ=ma x

[0036] Its vertical direction: F z =Fcosθ-G=ma z

[0037] Substituting the values, we get:

[0038] in:

[0039] a z Vehicle vertical vibration

[0040] m: Wheel mass, an inherent parameter of the vehicle, known during vehicle design.

[0041] G: The weight of the wheels and the vehicle body is an inherent parameter of the vehicle and is known during vehicle design.

[0042] I: Wheel moment of inertia, an inherent parameter of the vehicle, known during vehicle design.

[0043] r: Wheel radius, an inherent parameter of the vehicle, known during vehicle design.

[0044] θ: Angle between the starting ramp of the speed bump and the ground

[0045] Wheel angular acceleration

[0046] Furthermore, the signals regarding the wheel rotation direction include steering angle, angular velocity, or angular acceleration, and the displacement, velocity, or acceleration of the vehicle in the direction of travel calculated from these. Combining the vehicle's displacement, velocity, or acceleration in the direction of travel with the wheel radius yields the wheel steering angle, angular velocity, or angular acceleration. This solution uses information about the wheel rotation direction to control the vertical damping force of the shock absorber. However, this information includes the wheel's steering angle, rotational speed, and angular acceleration. Multiplying these by the wheel radius allows calculation of the vehicle's displacement, velocity, or acceleration in the direction of travel. These are signals more commonly used in automotive software development, and there are conversion relationships between them; one parameter can be transformed into another. In other words, the damping force of the shock absorber can be controlled using all the above information (wheel steering angle, rotational speed, angular acceleration; vehicle displacement, velocity, acceleration, etc.).

[0047] The wheel rotation direction signal mentioned in this embodiment includes the rotation angle, angular velocity, or angular acceleration of the wheel or a component mechanically connected to the wheel, as well as other signals processed based on these. Other signals refer to the rotation angle, rotational speed, or angular acceleration of components such as the wheel, main reducer, gearbox, engine, and motor. Since these components are fixedly connected to the wheel, their motion signals are theoretically completely consistent with the wheel speed, and therefore can also reflect the road surface excitation experienced by the wheel.

[0048] Furthermore, in this embodiment, the unsprung motion of the vehicle is sensed by wheel speed sensor signals, and the sprung motion of the vehicle is sensed by one or more of the following: gyroscope, sprung acceleration sensor, or vehicle height sensor. Based on the sprung and unsprung motion information of the vehicle, the controller calculates the damping force, stiffness, or active force required by the current vehicle, and then adjusts and controls the suspension based on the calculated data.

[0049] In a preferred embodiment, the unsprung motion information of the vehicle can be calculated by combining one or more wheel rotation signals with one or more unsprung vibration signals. Since a vehicle has four wheels, each wheel is controlled independently during suspension control. Therefore, in practical applications, one, two, three, or four unsprung acceleration sensors can be omitted; those not omitted are still used to acquire data for suspension control. That is, the unsprung vibration signal detected by the wheel speed sensor can be used for one wheel (while the other three wheels still use acceleration sensors), or it can be applied to two, three, or all four wheels. Wheel speed sensors and unsprung acceleration sensors can be interchanged, and their number is not fixed. The wheel rotation signals calculate the unsprung motion information, which reflects the unsprung vibration.

[0050] As shown in Figures 1-4, this embodiment proposes a vehicle suspension control system, which includes: a controller 10, a sprung sensor, a wheel speed sensor 101, and an actuator. The controller 10 is implemented using a microcontroller 103; the actuator can be a commonly used continuously damped adjustable semi-active shock absorber, or an active shock absorber or other components that can adjust the suspension damping or stiffness.

[0051] The number of wheel speed sensors can be one, two, three, or four. The wheel speed sensor 101 is connected to the controller 10 via one or more of the following methods: direct hard-wired connection, wireless connection, or CAN connection. The wheel speed sensor 101 can be directly connected to the controller or indirectly connected to the controller 10. Direct connection includes: the wheel speed sensor 101 is directly connected to the controller 10 via hard-wired, wireless, or CAN connection methods. Indirect connection includes: the wheel speed sensor 101 is connected to the controller 10 by forwarding signals from the vehicle controller. That is, the vehicle controller processes the signals collected by the wheel speed sensor and then forwards them to the controller 10. The vehicle controller is a reused version of the vehicle's original controllers, including but not limited to ABS and VCU. Each wheel speed sensor corresponds to one wheel and is used to sense the unsprung motion information of the wheel.

[0052] The on-spring sensor is connected to the controller via CAN / FlexRay or directly integrated into the controller.

[0053] The on-sprung sensor is used to collect on-sprung vibration information, and the wheel speed sensor 101 is used to collect the wheel rotation signal to sense unsprung vibration information. The controller 10 realizes the adjustment control of the suspension based on the on-sprung and unsprung information.

[0054] In embodiments of the present invention, the sprung sensor can be implemented using one or more of a gyroscope, a sprung accelerometer, and a vehicle high-speed sensor. Figures 1-4 are schematic diagrams of the control system structure for implementing the sprung sensor using a gyroscope 105, a sprung accelerometer 110, and a vehicle high-speed sensor 112, respectively. As shown in Figure 1, a schematic diagram of a vehicle suspension control system using a gyroscope to implement the sprung sensor is provided. This control system includes: a controller 10, a wheel speed sensor 101, a gyroscope 105, a battery 107, and an electronically controlled shock absorber 109. The controller 10 receives information collected by the wheel speed sensor 101 and the gyroscope 105 through the wheel speed sensor interface module 102 and the gyroscope interface module 106, respectively. The power management module 108 manages the power supply to the battery 107 to control the power supply to the microcontroller 103. The electronically controlled shock absorber current drive module 104 enables the microcontroller 103 to output current to the electronically controlled shock absorber 109. The electronically controlled shock absorber 109 provides different damping forces to the suspension system according to the current control current and the shock absorber speed. The gyroscope 105 is connected to the controller 10 via CAN or FlexRay.

[0055] Figure 2 shows a schematic diagram of another vehicle suspension control system that uses a gyroscope to implement an on-sprung sensor. The gyroscope 105 is directly integrated into the controller 10.

[0056] Figure 3 shows the schematic diagram of a vehicle suspension control system using an on-sprung acceleration sensor. The control system includes a controller 10, wheel speed sensors 101, on-sprung acceleration sensors 110, and actuators. The controller 10 receives information collected by the wheel speed sensors 101 and the on-sprung acceleration sensors 110 through wheel speed sensor interface module 102 and acceleration sensor interface module 113, respectively. The number of on-sprung acceleration sensors 110 can be one, two, three, or four. The connection between the on-sprung acceleration sensors 110 and the controller 10 can be CAN / FlexRay / LIN or a direct hardwired connection.

[0057] Figure 4 shows the schematic diagram of a vehicle suspension control system that uses high-speed body sensors to implement sprung sensors. The control system includes a controller 10, wheel speed sensors 101, vehicle height sensors 112, and actuators. The controller 10 receives information collected by the wheel speed sensors 101 and vehicle height sensors 112 through wheel speed sensor interface module 102 and vehicle height sensor interface module 113, respectively. The number of vehicle height sensors 112 can be one, two, three, or four. The connection between the vehicle height sensors 112 and the controller 10 can be CAN / FlexRay / LIN or a direct hardwired connection.

[0058] In one embodiment of the present invention, the gyroscope is a 6-DOF gyroscope or a 3-DOF gyroscope. It includes at least pitch, roll, or vertical acceleration signals.

[0059] As shown in Figure 5, a second aspect of the present invention provides a vehicle that includes a vehicle suspension control system as described in the above embodiments.

[0060] In this embodiment, a suspension control method, system, and vehicle based on wheel rotation signals are proposed. By replacing the acceleration sensor signal with the wheel speed sensor signal, the acceleration sensor is saved, thereby reducing the overall vehicle manufacturing cost and simplifying manufacturing and assembly.

[0061] In this embodiment, the technical innovations of this solution include:

[0062] 1. A control method for an electronically controlled suspension, wherein a wheel rotation signal is used instead of a wheel vertical signal for controlling the electronically controlled suspension.

[0063] 2. Wheel rotation signals include, but are not limited to, the speed, acceleration, or angle of wheel rotation. These signals can be obtained from one or more of the following components: wheel speed sensor, motor connected to the wheel, drive shaft, transfer case, gearbox, etc.

[0064] 3. Wheel vertical signals include, but are not limited to, one or more of the displacement, velocity, and acceleration of the unsprung mass along the vertical direction of the vehicle under the constraints of other suspension components. These signals can be obtained from one or more components such as unsprung acceleration sensors, height sensors, vehicle body acceleration sensors, and gyroscopes.

[0065] 4. The control objects of the suspension include one or more of the following: damping force of the suspension damper, spring stiffness, suspension height, main force of the active damper, or other adjustable suspension forces.

[0066] Obviously, the specific implementation of this invention is not limited to the above-described methods. Any non-substantial improvements made using the inventive concept and technical solution of this invention are within the protection scope of this invention.

Claims

1. A suspension control method based on wheel rotation signals, characterized in that: The system senses wheel vibrations caused by road surface excitation by detecting signals of wheel rotation direction and uses the sensed wheel vibration signals for suspension adjustment and control.

2. The suspension control method based on wheel rotation signals as described in claim 1, characterized in that: The signals indicating the direction of wheel rotation include one or a combination of rotation angle, angular velocity, angular acceleration, and one or more derivatives of angular acceleration.

3. The suspension control method based on wheel rotation signals as described in claim 1, characterized in that: When the excitation from the road surface to the wheels changes, the signal indicating the direction of wheel rotation changes. When the controller receives the changed signal, it adjusts and controls the suspension according to the needs of vehicle tuning. The adjustment and control of the suspension includes one or a combination of suspension damping adjustment, suspension stiffness adjustment, and suspension active force adjustment.

4. A suspension control method based on wheel rotation signals as described in claim 1 or 2, characterized in that: The signal of the wheel rotation direction, after being converted through the wheel radius, is equivalent to the wheel's displacement, velocity, acceleration, and one or more derivatives of the acceleration in the direction of travel.

5. A suspension control method based on wheel rotation signals as described in claim 1 or 2, characterized in that: The vehicle obtains unsprung motion information by collecting signals of wheel rotation direction from onboard wheel speed sensors. The vehicle's sprung motion signals are then detected by one or more of the following: gyroscope, sprung acceleration sensor, or vehicle height sensor. Based on the vehicle's sprung and unsprung motion information, the controller calculates the damping force, stiffness, or active force required by the vehicle.

6. The suspension control method based on wheel rotation signals as described in claim 5, characterized in that: The unsprung motion information of the vehicle is obtained by comprehensively calculating the rotation signals of four wheels; or by comprehensively calculating the unsprung motion information of the vehicle using one or more wheel rotation signals in conjunction with one or more unsprung vibration signals.

7. A suspension control system based on wheel rotation signals, characterized in that: The control system includes a controller, wheel speed sensors, and sprung sensors. The wheel speed sensors are used to collect signals of the wheel rotation direction, and their output is connected to the controller. The sprung sensors are used to sense the sprung motion signals of the vehicle, and their output is connected to the controller. The controller senses unsprung motion information based on the wheel rotation direction signals. The controller calculates the damping force, stiffness, or active force required by the vehicle based on the unsprung and sprung motion information and performs damping adjustment control on the suspension.

8. A suspension control system based on wheel rotation signals as described in claim 7, characterized in that: The sprung sensor includes one or any combination of a gyroscope, a sprung accelerometer, or a vehicle height sensor, used to sense one or more sprung motion signals of the sensing vehicle.

9. A suspension control system based on wheel rotation signals as described in claim 7, characterized in that: The on-spring sensor is connected to the controller via CAN / flexray / LIN or hardwire to upload the collected information to the controller.

10. A suspension control system based on wheel rotation signals as described in claim 8, characterized in that: The gyroscope is a 6-DOF gyroscope or a 3-DOF gyroscope.

11. The suspension control system based on wheel rotation signals as described in claim 7, further comprising: An electronically controlled shock absorber is used to provide different damping forces to the suspension system based on the current control current and the shock absorber speed. And an electronically controlled vibration damper current drive module, used to enable the controller to output current to the electronically controlled vibration damper.

12. A vehicle, characterized in that: The vehicle includes a suspension control system based on wheel rotation signals as described in any one of claims 7-11, or uses a suspension control method based on wheel rotation signals as described in any one of claims 1-6 for suspension control adjustment.

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