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

Abstract

The invention discloses a control method and system for adjusting suspension damping based on a wheel speed sensor signal. Wheel vibration caused by road excitation is sensed through the wheel speed sensor signal, and the sensed wheel vibration signal is used for adjusting and controlling the damping of a suspension and the like. According to the scheme, a wheel speed sensor commonly existing on a vehicle can be used for replacing an unsprung acceleration sensor needed in an industrial electric control shock absorber scheme, data are obtained, unsprung motion information of the vehicle is sensed, and therefore adjustment and control over damping and the like of the suspension are achieved. An unsprung acceleration sensor can be omitted for an electric control shock absorber system, the design and manufacturing cost is reduced, and the system assembling difficulty is reduced.

Description

Technical Field

[0001] The present 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 Art

[0002] In the prior art, semi-active suspension damping adjustment of a vehicle usually requires obtaining a signal based on the vertical vibration of the wheel. Generally speaking, the method for measuring the vertical vibration of the wheel is to use an unsprung acceleration sensor to directly measure the vertical acceleration of the wheel. Using an unsprung acceleration sensor will incur corresponding hardware costs.

[0003] In order to accurately measure the vehicle speed, a wheel speed sensor is usually installed to measure the rotation speed of the wheel. Since the vertical acceleration of the wheel and the angular acceleration of the rotation direction are both motion state parameters of the wheel, both are characterization parameters of the wheel or unsprung mass state. When the wheel is excited by an uneven road surface, the vertical acceleration of the wheel and the angular acceleration of the wheel in the rotation direction will change at the same time.

[0004] By extracting the changing characteristics of the rotational angular acceleration, the unevenness of the road surface and the degree of excitation brought to the wheels by the road surface can be identified. In this way, the unsprung acceleration sensor can be saved, avoiding the increase in vehicle manufacturing costs and the increase in the difficulty of vehicle assembly. There is no solution to eliminate the unsprung acceleration sensor in the prior art. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and propose a suspension control method that senses the unsprung vibration of a vehicle based on a wheel rotation signal and then controls the suspension damping force. The unsprung acceleration sensor can be replaced by a wheel speed sensor commonly found on vehicles. Eliminating the unsprung acceleration sensor can reduce manufacturing costs and reduce the difficulty of system assembly.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A suspension control method based on wheel rotation signals, which senses wheel vibration caused by road excitation through wheel rotation direction signals and uses the sensed wheel vibration signals for suspension adjustment control

[0008] The signal of the wheel rotation direction includes one of the rotation angle, angular velocity, angular acceleration, and the first or multiple derivatives of the angular acceleration, or a combination thereof.

[0009] When the excitation of the road surface to the wheel changes, the signal of the wheel rotation direction will change. When the controller receives the changed signal, it can adjust the suspension according to the needs of vehicle training. The adjustment control of the suspension includes one or a combination of suspension damping adjustment, suspension stiffness adjustment and suspension active force adjustment.

[0010] After the signal of the wheel rotation direction is converted through the wheel radius, it can be equivalent to the displacement, velocity, acceleration, or one or more differentials of the acceleration of the wheel in the driving direction.

[0011] The vehicle's unsprung motion information is acquired based on the signal sensed by the wheel rotation direction collected by the on-vehicle wheel speed sensor, and the vehicle's sprung motion signal is sensed by one or more of the gyroscope, sprung acceleration sensor, or body height sensor. The damping force, stiffness, or active force required by the current vehicle is calculated by the controller based on the vehicle's sprung and unsprung motion information.

[0012] The unsprung motion information of the vehicle is obtained by comprehensive calculation using four wheel rotation signals; or the unsprung motion information of the vehicle is obtained by comprehensive calculation using one or more wheel rotation signals combined with one or more unsprung vibration signals.

[0013] The control system includes a controller, a wheel speed sensor, and a sprung sensor; the wheel speed sensor is used to collect signals of the wheel rotation direction, and its output end is connected to the controller; the sprung sensor is used to sense the vehicle sprung motion signal, and its output end is connected to the controller; the controller obtains unsprung motion information based on the signal perception of the wheel rotation direction, and the controller calculates the damping force, stiffness or active force required by the current vehicle based on the unsprung and sprung motion information and performs damping adjustment control on the suspension.

[0014] The sprung sensor includes one or any combination of a gyroscope, a sprung acceleration sensor, or a vehicle height sensor, which is used to sense one or more sprung motion signals of the vehicle.

[0015] The sprung sensor is connected to the controller via CAN / flexray / LIN or hard wire to upload the collected information to the controller.

[0016] A vehicle comprises the suspension control system based on wheel rotation signals or adopts the suspension control method based on wheel rotation signals to perform suspension control adjustment.

[0017] The invention has the advantages that: by replacing the acceleration sensor signal with the wheel speed sensor signal, the acceleration sensor is saved, the manufacturing cost of the whole vehicle is reduced and the manufacturing assembly is simplified. The unsprung acceleration sensor in the semi-active suspension system is cancelled, the wheel speed sensor of the electronic control brake system is reused, and the unsprung acceleration sensor signal is replaced with the wheel speed sensor signal, which saves the manufacturing cost of the whole vehicle, simplifies the manufacturing process, and saves the layout space in the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The following is a brief description of the contents expressed in the drawings of the present invention and the symbols in the drawings:

[0019] Figure 1 This is a schematic diagram of the structure of a vehicle control system in Embodiment 1 of the present invention;

[0020] Figure 2 It is a structural schematic diagram of a vehicle control system in Embodiment 2 of the present invention;

[0021] Figure 3 Schematic diagram of the structure of a vehicle control system in Embodiment 3 of the present invention;

[0022] Figure 4 This is a schematic diagram of the structure of a vehicle control system in Embodiment 4 of the present invention;

[0023] Figure 5 It is a schematic diagram of the vehicle structure of the present invention;

[0024] Figure 6 This is a flow chart of the principle of judging that a vehicle passes through a speed bump in a vertical direction based on wheel speed sensor data perception of the present invention;

[0025] Figure 7 This is a schematic diagram of the wheel principle corresponding to the vertical motion calculation of the wheel of the present invention.

[0026] The marks in the above figures are: 1. Vehicle; 10. Controller; 101. Wheel speed sensor; 102. Wheel speed sensor interface module; 103. Single chip microcomputer; 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. Sprung acceleration sensor; 111. Sprung acceleration sensor interface module; 112. Vehicle body high speed sensor; 113. Height sensor interface module. DETAILED DESCRIPTION

[0027] The specific implementation of the present invention will be further explained in detail below by describing the optimal embodiment with reference to the accompanying drawings.

[0028] 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 electronically controlled braking system, and replaces the unsprung acceleration sensor signal with the wheel speed sensor signal, thereby saving the manufacturing cost of the entire vehicle, simplifying the manufacturing process, and saving space in the vehicle.

[0029] In the prior art, the adjustment and control of the suspension requires the use of unsprung motion information, which can be collected by adding an unsprung acceleration sensor. However, adding an unsprung acceleration sensor will increase the cost and increase the difficulty in production and assembly. In view of this, this solution proposes a method of using the wheel speed sensor signal to sense the unsprung motion information for use in the suspension damping adjustment and control. The specific solution is as follows:

[0030] A method for controlling an electronically controlled suspension, which multiplexes the wheel speed sensor on the vehicle to collect the signal of the wheel rotation direction, and obtains the excitation of the wheel by the uneven road surface through the signal of the wheel rotation direction, and replaces the conventional vertical acceleration sensor / displacement sensor in the industry for the control of the electronically controlled suspension. The signal of the wheel rotation direction collected by the wheel speed sensor includes one or more of the rotation angle, angular velocity, angular acceleration and the differential of angular acceleration.

[0031] In this embodiment, since the vehicle needs to convert the wheel speed signal to obtain the vehicle speed signal, basically each vehicle will be equipped with a wheel speed sensor. Therefore, the reuse of the wheel speed sensor in this solution does not incur hardware costs, and can also reduce the hardware cost of the unsprung acceleration sensor, which can achieve cost savings and save one part installation for each wheel; in this solution, when the vehicle travels over an uneven road surface, the wheel will vibrate vertically, and the signal of the wheel rotation direction will also undergo a specific change at the same time. The electronically controlled suspension control method proposed in the present invention can sense the excitation of the wheel (unsprung mass) by the uneven road surface according to the signal change of the wheel rotation direction at this time, and then control the damping or stiffness or active force of the suspension. The vibration of the wheel in the vertical direction is the unsprung vibration information, and the suspension controller can realize the damping control of the suspension according to the unsprung vibration information and the collected sprung vibration information.

[0032] like Figure 6 As shown in the figure, the first condition, the second condition, and the third condition are the speed bump characteristic threshold corresponding to the wheel angular velocity, the speed bump characteristic threshold corresponding to the wheel angular acceleration, and the speed bump characteristic threshold corresponding to the wheel angular acceleration differential value, respectively. Taking the judgment of whether the vehicle passes through the speed bump as an example, the value of the vehicle wheel speed sensor is first judged. If the wheel speed value meets the speed bump characteristic threshold, then the wheel speed sensor signal change speed is judged. If the wheel speed sensor signal change speed value meets the speed bump characteristic threshold, then the wheel speed sensor signal change acceleration is judged. If the wheel speed sensor signal change acceleration value meets the speed bump characteristic threshold, then it is considered that the vehicle has passed the speed bump at this time, and the speed bump control algorithm is immediately started for the shock absorber: first, the minimum damping force is maintained to ease 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 passing the speed bump. Other characteristic roads are identified and judged in a similar manner.

[0033] Furthermore, the vertical movement of the wheel can also be obtained by calculating and calibrating the signal based on the wheel rotation direction.

[0034] like Figure 7 As shown in the figure, taking the example of a vehicle driving over a speed bump, when the tire passes over the speed bump, its horizontal direction is:

[0035] F x =Fsinθ=ma x

[0036] Its vertical direction:

[0037] F z =Fcosθ-G=ma z Substitute it into:

[0038]

[0039] in:

[0040] a z :Vertical vibration of vehicle

[0041] m: wheel mass, which is an inherent parameter of the vehicle and can be known during vehicle design.

[0042] G: The weight of the wheels and the vehicle body, which is an inherent parameter of the vehicle and can be known during vehicle design.

[0043] I: Wheel moment of inertia, an inherent parameter of the vehicle, known during vehicle design

[0044] r: wheel radius, which is an inherent parameter of the vehicle and can be known during vehicle design.

[0045] θ: Angle between the starting slope of the speed bump and the ground

[0046] Wheel angular acceleration

[0047] Furthermore, the signal of the wheel rotation direction includes the angle, angular velocity or angular acceleration, etc., and the displacement, speed or acceleration of the vehicle in the driving direction can be calculated therefrom. The displacement, speed or acceleration of the vehicle in the driving direction can be combined with the wheel radius to obtain the wheel angle, angular velocity or angular acceleration. This scheme uses the information of the wheel rotation direction to control the vertical damping force of the shock absorber, but the information of the wheel rotation direction includes the wheel angle, rotation speed and angular acceleration. Multiplying by the wheel radius can calculate the displacement, speed or acceleration of the vehicle in the driving direction. In the development of automotive software, everyone is more accustomed to using signals. There is a conversion relationship between these signals, and one parameter can be converted into another parameter through conversion. In other words, the damping force of the shock absorber can be controlled by all the above information (wheel angle, rotation speed, angular acceleration, vehicle displacement, speed, acceleration, etc.).

[0048] The wheel rotation direction signal mentioned in this embodiment includes the rotation angle, angular velocity or angular acceleration of the wheel or the component mechanically connected to the wheel, as well as other signals processed on this basis. Other signals refer to the rotation angle, rotation speed or angular acceleration of components such as wheels, final reducers, gearboxes, engines, motors, etc. Since these components are fixedly connected to the wheels, their motion signals are theoretically completely consistent with the wheel speed, so they can also reflect the road excitation received by the wheels.

[0049] Furthermore, in the present embodiment, the unsprung motion of the vehicle is sensed by the wheel speed sensor signal, and the sprung motion of the vehicle is sensed by one or more of the gyroscope, the sprung acceleration sensor, or the 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.

[0050] In a preferred solution of this embodiment, one or more wheel rotation signals can be used in combination with one or more unsprung vibration signals to comprehensively calculate the unsprung motion information of the vehicle. Since the vehicle has four wheels, each wheel is controlled separately when performing suspension control. Therefore, in actual application, one, two, three or four unsprung acceleration sensors can be eliminated, and the unsprung acceleration sensors are still used to obtain data and perform suspension control if they are not eliminated; that is, the unsprung vibration signal sensed by the wheel speed sensor can be used for one of the wheels (in this case, the other three wheels also use acceleration sensors), and can also be applied to two, three or all four wheels, that is, the wheel speed sensor and the unsprung acceleration sensor can be replaced with each other, and the number is not fixed. The wheel rotation signal calculates the unsprung motion information, and this motion information can reflect the unsprung vibration.

[0051] like Figure 1-4 As shown, this embodiment proposes a vehicle suspension control system, which includes: a controller, a sprung sensor, a wheel speed sensor, and an actuator. The controller is implemented by a single-chip microcomputer; the actuator can be a continuous damping adjustable semi-active shock absorber commonly used in the industry, or an active shock absorber or other components that can adjust the suspension damping or stiffness.

[0052] The number of wheel speed sensors is 1 or 2 or 3 or 4. The connection between the wheel speed sensor and the controller is one or more of hardwired direct 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, wherein the direct connection includes: the wheel speed sensor 101 is directly connected to the controller 10 through hardwire, wireless, CAN and other connection methods; the indirect connection includes: the wheel speed sensor 101 is connected to the controller 10 by forwarding the signal through the vehicle-mounted controller, that is, the wheel speed sensor 101 is connected to the vehicle-mounted controller, and the vehicle-mounted controller processes the signal collected by the wheel speed sensor and then forwards it to the controller 10 by the vehicle-mounted controller. The vehicle-mounted controller is a reused original controller of the vehicle, including but not limited to ABS, VCU, etc. Each wheel speed sensor corresponds to one of the wheels, which is used to sense the unsprung motion information of the wheel.

[0053] The sprung sensor is connected to the controller via CAN / flexray or is directly integrated into the controller.

[0054] The sprung sensor is used to collect sprung vibration information, and the wheel speed sensor is used to collect wheel rotation signals to sense unsprung vibration information. The controller adjusts and controls the suspension based on the sprung and unsprung information.

[0055] In this embodiment, the sprung sensor can be implemented by one or more of a gyroscope, a sprung acceleration sensor, and a vehicle body high speed sensor. Figure 1 As shown in the figure, the control system structure schematic diagram of the sprung sensor is realized by using a gyroscope, a sprung acceleration sensor, and a body high-speed sensor. In the figure, the power management module is used to manage the battery power supply to realize the power supply control of the single-chip microcomputer; the semi-active shock absorber current drive module is used to realize the current output of the single-chip microcomputer to the shock absorber; the semi-active shock absorber provides different damping forces to the suspension system according to the current control current and the shock absorber speed. The connection method between the gyroscope and the controller is CAN or flexray.

[0056] like Figure 2 As shown, it is a schematic diagram of another vehicle suspension control system that uses a gyroscope to implement a sprung sensor. The gyroscope is connected to the controller by being directly integrated into the controller.

[0057] like Figure 3 As shown, it is a schematic diagram of a vehicle suspension control system using a sprung acceleration sensor to realize a sprung sensor, wherein the control system includes a controller, a wheel speed sensor, a sprung acceleration sensor, and an actuator. The number of sprung acceleration sensors is 1, 2, 3, or 4. The sprung acceleration sensor is connected to the controller by CAN / flexray / LIN or hard wire direct connection.

[0058] like Figure 4 As shown, it is a schematic diagram of a vehicle suspension control system that uses a vehicle body high-speed sensor to implement a sprung sensor, wherein the control system includes a controller, a wheel speed sensor, a vehicle body height sensor, and an actuator. The number of vehicle body height sensors is 1, 2, 3, or 4. The vehicle body height sensor is connected to the controller by CAN / flexray / LIN or hard wire direct connection.

[0059] In one embodiment of the present invention, the gyroscope is a 6-DOF gyroscope or a 3-DOF gyroscope, which at least includes pitch, roll or vertical acceleration signals.

[0060] like Figure 5 As shown, a second embodiment of the present invention provides a vehicle, which includes a vehicle suspension control system in the above embodiment.

[0061] In this embodiment, a suspension control method, system and vehicle based on wheel rotation signals save acceleration sensors by replacing acceleration sensor signals with wheel speed sensor signals, thereby reducing vehicle manufacturing costs and simplifying manufacturing and assembly.

[0062] In this embodiment, the technical innovations of this solution include:

[0063] 1. A control method for an electronically controlled suspension, which uses a wheel rotation signal instead of a wheel vertical signal to control the electronically controlled suspension.

[0064] 2. Wheel rotation signals include but are not limited to the speed, acceleration or angle of the wheel rotation direction. The signal can be obtained by one or more of the wheel speed sensor, the motor connected to the wheel, the drive shaft, the transfer case, the gearbox and other components.

[0065] 3. The wheel vertical signal includes but is 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. The signal can be obtained by one or more of the unsprung acceleration sensor, height sensor, body acceleration sensor, gyroscope and other components.

[0066] 4. The control objects of the suspension include one or more of the damping force of the suspension shock absorber, spring stiffness, suspension height, active force of the active shock absorber or other adjustable suspension forces.

[0067] Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, they are all within the protection scope of the present invention.

Claims

1. A suspension control method based on a wheel rotation signal, characterized in that: The wheel vibration caused by road excitation is sensed through the wheel rotation direction signal and the sensed wheel vibration signal is used for suspension adjustment control.

2. A suspension control method based on wheel rotation signals as claimed in claim 1, characterized in that: The signal of the wheel rotation direction includes one of the rotation angle, angular velocity, angular acceleration, and the first or multiple derivatives of the angular acceleration, or a combination thereof.

3. A suspension control method based on wheel rotation signals as claimed in claim 1, characterized in that: When the excitation of the wheel by the road surface changes, the signal of the wheel rotation direction will change. When the controller receives the changed signal, it adjusts the suspension according to the needs of vehicle tuning; the suspension adjustment control 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 claimed in claim 1 or 2, characterized in that: The signal of the wheel rotation direction is equivalent to the displacement, velocity, acceleration, or one or more differentials of the acceleration of the wheel in the driving direction after being converted by the wheel radius.

5. A suspension control method based on wheel rotation signals as claimed in claim 1 or 2, characterized in that: The vehicle's unsprung motion information is acquired based on the signal sensed by the wheel rotation direction collected by the on-vehicle wheel speed sensor, and the vehicle's sprung motion signal is sensed by one or more of the gyroscope, sprung acceleration sensor, or body height sensor. The damping force, stiffness, or active force required by the current vehicle is calculated by the controller based on the vehicle's sprung and unsprung motion information.

6. A suspension control method based on wheel rotation signals as claimed in claim 5, characterized in that: The unsprung motion information of the vehicle is obtained by comprehensive calculation using four wheel rotation signals; or the unsprung motion information of the vehicle is obtained by comprehensive calculation using one or more wheel rotation signals combined 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, a wheel speed sensor, and a sprung sensor; the wheel speed sensor is used to collect signals of the wheel rotation direction, and its output end is connected to the controller; the sprung sensor is used to sense the vehicle sprung motion signal, and its output end is connected to the controller; the controller obtains unsprung motion information based on the signal perception of the wheel rotation direction, and the controller calculates the damping force, stiffness or active force required by the current 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 claimed in claim 7, characterized in that: The sprung sensor includes one or any combination of a gyroscope, a sprung acceleration sensor, or a vehicle height sensor, which is used to sense one or more sprung motion signals of the vehicle.

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

10. A vehicle, characterized in that: The vehicle includes a suspension control system based on a wheel rotation signal as described in any one of claims 7-9 or adopts a suspension control method based on a wheel rotation signal as described in any one of claims 1-6 to perform suspension control adjustment.

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