A semi-active hydraulic suspension control method and system based on dSPACE

Abstract

This invention relates to a semi-active hydraulic suspension control method and system based on dSPACE. Specifically, the control method involves: determining the current state of the vehicle, either a parked state or a driving state; in a parked state, if the engine speed is 0 or greater than or equal to a first speed threshold, de-energizing the solenoid valve; if the engine speed is not 0 and less than the first speed threshold, energizing the solenoid valve; in a driving state, opening or closing the solenoid valve based on the vehicle speed and engine speed. This invention modifies the damping characteristics of the vehicle's semi-active hydraulic suspension by detecting vehicle speed and engine speed signals, improving the vibration isolation effect of the suspension system and reducing the energy transmitted from the powertrain to the frame or body under different operating conditions.

Description

Technical Field

[0001] This invention relates to the field of vehicle control technology, and more specifically to NVH technology. Background Technology

[0002] With technological advancements, people's performance requirements for automobiles are increasing, and future cars are gradually developing towards comfort, energy efficiency, environmental friendliness, and intelligence. During normal driving, vehicles primarily receive excitation from the road surface and engine. The engine, as a major source of vibration, transmits vibrations to the passenger compartment through the body and subframe, affecting the driving and riding experience. Suspension mounts, as a connection mechanism between the body and frame, provide protection such as limiting and isolating vibrations, reducing engine-transmitted vibrations, and supporting the connection between the body and powertrain. Widely used types include rubber mounts, hydraulic mounts, and air mounts. Rubber mounts have low damping, resulting in poor vibration reduction during significant engine vibrations. Compared to rubber mounts, hydraulic mounts exhibit high damping at low frequencies, providing vibration reduction. However, as engine frequency increases, high-frequency hardening still occurs, leading to a decrease in vibration reduction effectiveness and consequently reducing passenger comfort. Summary of the Invention

[0003] One objective of this invention is to provide a semi-active hydraulic suspension control method based on dSPACE to solve the problem that when using rubber or hydraulic suspension alone, the vibration reduction effect decreases when the engine vibrates or the frequency changes, resulting in reduced passenger comfort. Another objective is to provide a semi-active hydraulic suspension control system.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A semi-active hydraulic suspension control method based on dSPACE, wherein the control method specifically comprises:

[0006] Determine the current state of the vehicle, which may be either a parked state or a moving state;

[0007] When the engine is in a parked state, if the engine speed is 0 or the engine speed is greater than or equal to the first speed threshold, the solenoid valve is de-energized; if the engine speed is not 0 and is less than the first speed threshold, the solenoid valve is energized.

[0008] When the vehicle is in driving mode, if the vehicle speed is greater than or equal to the vehicle speed threshold, the solenoid valve will be de-energized when the engine speed is greater than the second speed threshold.

[0009] If the vehicle speed is less than the vehicle speed threshold, it is determined whether the engine speed is within the first preset range. If so, the solenoid valve is de-energized. If not, the solenoid valve is energized when the engine speed is within the second preset range. Both the first and second preset ranges are open ranges. The maximum value of the first preset range is less than or equal to the minimum value of the second preset range.

[0010] Based on the above technical means, when the car is parked, the engine speed increases sharply at the moment of starting, resulting in low-frequency, large-amplitude vibration. The control valve is energized, which enables the suspension to achieve a state of high stiffness and high damping, ensuring starting comfort. When the engine is running normally, the engine excitation is high-frequency, small-amplitude vibration. At this time, the solenoid valve built into the suspension is energized, and the suspension characteristics are in a state of low stiffness and low damping, which can play a good role in shock absorption and noise reduction.

[0011] When in driving mode, based on vehicle speed and engine speed, when the vehicle speed is greater than the vehicle speed threshold and the engine speed is greater than the second speed threshold, or when the vehicle speed is less than the vehicle speed threshold and the engine speed is within the first speed range, according to the actual engine performance, this is a high-frequency, low-amplitude state, requiring the solenoid valve to be de-energized, and the suspension state to be low-damped and low-stiffness; when the vehicle speed is less than the vehicle speed threshold and the engine speed is within the second preset range, the actual engine performance is a low-frequency, high-amplitude state, requiring the solenoid valve to be energized, and the suspension state to be high-damped and high-stiffness.

[0012] Therefore, this technology, which adjusts the damping characteristics of the suspension based on the engine's state, has a better vibration reduction effect compared to using rubber dampers or hydraulic suspensions alone, thereby improving passenger comfort.

[0013] Furthermore, before determining the current state of the vehicle, the validity of the engine speed signal and the vehicle speed signal is checked. If both are valid, the current state of the vehicle is determined; otherwise, the process exits and continues to check the validity of the engine speed signal and the vehicle speed signal.

[0014] Furthermore, before detecting the validity of the engine speed signal and vehicle speed signal, if the vehicle CAN network is abnormal or the vehicle power module is in a closed state, the process will exit and continuously detect the status of the CAN network and the vehicle power module; if the vehicle CAN network is normal and the vehicle power module is in a closed state, the validity of the engine speed signal and vehicle speed signal will be detected.

[0015] Furthermore, after controlling the solenoid valve to be energized or de-energized, the current state of the vehicle is further determined.

[0016] Furthermore, the two boundary values ​​of the first preset interval are a first speed threshold and a third speed threshold, respectively, wherein the third speed threshold is greater than the first speed threshold and the third speed threshold is less than the second speed threshold.

[0017] Furthermore, the two boundary values ​​of the second preset interval are the third speed threshold and the second speed threshold, respectively.

[0018] A semi-active hydraulic suspension control system based on dSPACE based on the above control method includes: a vehicle state judgment module configured to judge the current state of the vehicle, wherein the state is a parking state or a driving state;

[0019] The enable judgment module is configured to receive information from the vehicle judgment module and issue corresponding signals based on engine speed and vehicle speed, specifically:

[0020] When the engine is in a parked state, if the engine speed is 0 or the engine speed is greater than or equal to the first speed threshold, the solenoid valve is de-energized; if the engine speed is not 0 and is less than the first speed threshold, the solenoid valve is energized.

[0021] When the vehicle is in motion, if the vehicle speed is greater than or equal to the vehicle speed threshold, a solenoid valve de-energization signal will be issued when the engine speed is greater than the second speed threshold.

[0022] If the vehicle speed is less than the vehicle speed threshold, it is determined whether the engine speed is within the first preset range. If so, a solenoid valve de-energization signal is issued. If not, when the engine speed is within the second preset range, a solenoid valve energization signal is issued. Both the first and second preset ranges are open ranges. The maximum value of the first preset range is less than or equal to the minimum value of the second preset range.

[0023] The enable execution module is configured to control the solenoid valve to be energized when it receives the solenoid valve energizing signal, and to control the solenoid valve to be de-energized when it receives the solenoid valve de-energizing signal.

[0024] Furthermore, it also includes a signal judgment module, configured to detect whether the engine speed signal and vehicle speed signal are valid before judging the current state of the vehicle. If both are valid, the enable judgment module is activated; otherwise, the enable judgment module is not activated, and the validity of the engine speed signal and vehicle speed signal is continuously detected.

[0025] Furthermore, it also includes a network and power judgment module, configured to not activate the signal judgment module if the vehicle CAN network is abnormal or the vehicle power module is in a closed state before detecting whether the engine speed signal and vehicle speed signal are valid, and to continuously monitor the status of the vehicle CAN network and the vehicle power module. If the vehicle CAN network is normal and the vehicle power module is in a closed state, the signal judgment module is activated.

[0026] Furthermore, the enable judgment module is dSPACE.

[0027] The beneficial effects of this invention are:

[0028] This invention modifies the damping characteristics of the semi-active hydraulic suspension of a car by detecting vehicle speed signals and engine speed signals, thereby improving the vibration isolation effect of the suspension system, reducing the energy transmitted from the powertrain to the frame or body under different operating conditions, and improving passenger comfort. Attached Figure Description

[0029] Figure 1 This is a flowchart of Embodiment 1 of the present invention;

[0030] Figure 2 This is a structural diagram of Embodiment 2 of the present invention.

[0031] Among them, 1-vehicle status judgment module; 2-enable judgment module; 3-enable execution module; 4-signal judgment module; 5-network and power judgment module. Detailed Implementation

[0032] The following description, with reference to the accompanying drawings and preferred embodiments, illustrates the implementation of the technical solution of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.

[0033] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0034] Example 1

[0035] This embodiment proposes a semi-active hydraulic suspension control method based on dSPACE, such as... Figure 1 As shown, the specific method is as follows:

[0036] S0: Acquire vehicle CAN network signals and power module signals. If the vehicle CAN network is abnormal or the vehicle power module is off, exit the process, i.e., do not perform semi-active hydraulic suspension control, and continuously monitor the status of the vehicle CAN network and the vehicle power module. If the vehicle CAN network is normal and the vehicle power module is on, proceed to S1. The power module's main function is to enable various vehicle systems to receive vehicle signals and analog voltage output signals normally.

[0037] S1: Detect whether the engine speed signal and vehicle speed signal are valid. If both are valid, proceed to S2; otherwise, exit, that is, do not perform semi-active hydraulic suspension control, while continuously monitoring the validity of the engine speed signal and vehicle speed signal.

[0038] S2: Determine the current state of the vehicle based on the vehicle speed signal. The state is either parked or moving. That is, when the vehicle speed is 0, the vehicle is parked, and when it is greater than 0, the vehicle is moving.

[0039] S3: When the engine is stationary, if the engine speed is 0 or greater than or equal to 750 rpm, the solenoid valve is de-energized, resulting in a low-stiffness, low-damping mount. If the engine speed is not 0 but less than 750 rpm, the solenoid valve is energized, resulting in a high-stiffness, high-damping mount. This is because during engine startup, the speed increases sharply, resulting in low-frequency, high-amplitude vibration. Energizing the valve ensures a high-stiffness, high-damping mount for smooth startup. During normal engine operation, the engine excitation is high-frequency, low-amplitude vibration. At this time, the solenoid valve inside the mount is energized, resulting in a low-stiffness, low-damping mount, which provides good vibration damping and noise reduction. The engine speed threshold can be calibrated and adjusted according to the engine's NVH characteristics.

[0040] For low-frequency, large-amplitude vibrations, it exhibits high stiffness and high damping to ensure driving comfort. For high-frequency, small-amplitude vibrations, it exhibits low stiffness and low damping to ensure good vibration reduction and noise reduction under idling conditions.

[0041] When the vehicle is in motion, if the vehicle speed is greater than or equal to 5, the solenoid valve will be de-energized when the engine speed is greater than 4000.

[0042] If the vehicle speed is less than 5, determine whether the engine speed is within the range of (750, 1000). If so, control the solenoid valve to de-energize. If not, control the solenoid valve to energize when the engine speed is within the range of (1000, 4000).

[0043] When the vehicle speed is greater than 5 km / h and the engine speed is greater than 4000 rpm, or when the vehicle speed is less than 5 km / h and the engine speed is between 750 and 1000 rpm, the engine is in a high-frequency, low-amplitude state, which requires the solenoid valve to be de-energized and the suspension to be in a low-damping, low-stiffness state. When the vehicle speed is less than 5 km / h and the engine speed is greater than 1000 rpm, the engine is in a low-frequency, high-amplitude state, which requires the solenoid valve to be energized and the suspension to be in a high-damping, high-stiffness state.

[0044] In this embodiment, the engine speed and vehicle speed are calibrable values, which are calibrated according to actual road conditions and adapted to different road conditions.

[0045] S4: Repeat S2.

[0046] Example 2

[0047] This embodiment proposes a semi-active hydraulic suspension control system based on dSPACE, such as... Figure 2 As shown, it includes a vehicle status judgment module 1, an enable judgment module 2, an enable execution module 3, a signal judgment module 4, and a network and power judgment module 5. Among them:

[0048] The vehicle status determination module 1 is configured to determine the current status of the vehicle, which is either a parked state or a driving state.

[0049] Enable judgment module 2, dSPACE, is configured to receive information from the vehicle judgment module and issue corresponding signals based on engine speed and vehicle speed. Specifically:

[0050] When the engine is in a parked state, if the engine speed is 0 or the engine speed is greater than or equal to the first speed threshold, the solenoid valve is de-energized; if the engine speed is not 0 and is less than the first speed threshold, the solenoid valve is energized.

[0051] When the vehicle is in motion, if the vehicle speed is greater than or equal to the vehicle speed threshold, a solenoid valve de-energization signal will be issued when the engine speed is greater than the second speed threshold.

[0052] If the vehicle speed is less than the vehicle speed threshold, it is determined whether the engine speed is within the first preset range. If so, a solenoid valve de-energization signal is issued. If not, when the engine speed is within the second preset range, a solenoid valve energization signal is issued. Both the first and second preset ranges are open ranges. The maximum value of the first preset range is less than or equal to the minimum value of the second preset range.

[0053] The enable execution module 3 is configured to control the solenoid valve to be energized when it receives the solenoid valve energizing signal, and to control the solenoid valve to be de-energized when it receives the solenoid valve de-energizing signal.

[0054] The signal judgment module 4 is configured to detect whether the engine speed signal and the vehicle speed signal are valid before judging the current state of the vehicle. If both are valid, the enable judgment module 3 is activated; otherwise, the enable judgment module 3 is not activated, and the validity of the engine speed signal and the vehicle speed signal is continuously detected.

[0055] The network and power judgment module 5 is configured to not activate the signal judgment module 4 if the vehicle CAN network is abnormal or the vehicle power module is in a closed state before detecting whether the engine speed signal and vehicle speed signal are valid, and to continuously monitor the status of the vehicle CAN network and the vehicle power module. If the vehicle CAN network is normal and the vehicle power module is in a closed state, then the signal judgment module 4 is activated.

[0056] In this embodiment, the dSPACE-based semi-active hydraulic suspension control system is part of the vehicle's CAN network controller system.

[0057] dSPACE is a powerful hardware and software simulation platform with rich I / O support, enabling code downloading and integrated embedded development based on Matlab / Simulink.

[0058] The semi-active hydraulic suspension controller developed based on dSPACE can read signals from different vehicle controllers on the CAN bus and directly control the opening and closing of the semi-active hydraulic suspension solenoid valve through dSPACE to switch the damping characteristics of the semi-active hydraulic suspension, thereby achieving driving comfort under different vibration characteristics.

[0059] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention.

Claims

1. A semi-active hydraulic suspension control method based on dSPACE, characterized in that: The control method is specifically as follows: Determine the current state of the vehicle, which may be either a parked state or a moving state; When the engine is in a parked state, if the engine speed is 0 or the engine speed is greater than or equal to the first speed threshold, the solenoid valve is de-energized; if the engine speed is not 0 and is less than the first speed threshold, the solenoid valve is energized. When the vehicle is in driving mode, if the vehicle speed is greater than or equal to a vehicle speed threshold, the solenoid valve is de-energized when the engine speed is greater than a second speed threshold. If the vehicle speed is less than the vehicle speed threshold, it is determined whether the engine speed is within a first preset range. If yes, the solenoid valve is de-energized; otherwise, the solenoid valve is energized when the engine speed is within a second preset range. Both the first and second preset ranges are open ranges, and the maximum value of the first preset range is less than or equal to the minimum value of the second preset range. The first speed threshold is 750 rpm, the vehicle speed threshold is 5 km / h, the second speed threshold is 4000 rpm, the first preset range is 750 rpm - 1000 rpm, and the second preset range is 1000 rpm - 4000 rpm. Before determining the current state of the vehicle, the validity of the engine speed signal and the vehicle speed signal is detected. If both are valid, the current state of the vehicle is determined; otherwise, the process exits and continues to detect the validity of the engine speed signal and the vehicle speed signal. When the solenoid valve is de-energized, it is suspended in a state of low stiffness and low damping; when energized, it is suspended in a state of high stiffness and high damping.

2. The control method according to claim 1, characterized in that: Before checking the validity of the engine speed signal and vehicle speed signal, if the vehicle CAN network is abnormal or the vehicle power module is in a closed state, the process will exit and continue to check the status of the CAN network and the vehicle power module; if the vehicle CAN network is normal and the vehicle power module is in a closed state, the validity of the engine speed signal and vehicle speed signal will be checked.

3. The control method according to claim 2, characterized in that: After controlling the solenoid valve to be energized or de-energized, the current status of the vehicle is determined.

4. The control method according to claim 1, characterized in that: The two boundary values ​​of the first preset interval are a first speed threshold and a third speed threshold, respectively. The third speed threshold is greater than the first speed threshold and less than the second speed threshold.

5. The control method according to claim 4, characterized in that: The two boundary values ​​of the second preset interval are the third speed threshold and the second speed threshold, respectively.

6. A semi-active hydraulic suspension control system based on the control method described in any one of claims 1-5, characterized in that: include: The vehicle status determination module is configured to determine the current status of the vehicle, which is either a parked state or a driving state. The enable judgment module is configured to receive information from the vehicle status judgment module and issue corresponding signals based on engine speed and vehicle speed, specifically: When the engine is in a parked state, if the engine speed is 0 or the engine speed is greater than or equal to the first speed threshold, the solenoid valve is de-energized; if the engine speed is not 0 and is less than the first speed threshold, the solenoid valve is energized. When in driving mode, if the vehicle speed is greater than or equal to a vehicle speed threshold, then when the engine speed exceeds a second speed threshold, an alarm will be triggered. Signal; If the vehicle speed is less than the vehicle speed threshold, it is determined whether the engine speed is within the first preset range. If so, a solenoid valve de-energization signal is issued. If not, when the engine speed is within the second preset range, a solenoid valve energization signal is issued. Both the first and second preset ranges are open ranges. The maximum value of the first preset range is less than or equal to the minimum value of the second preset range. The enable execution module is configured to control the solenoid valve to be energized when it receives the solenoid valve energizing signal, and to control the solenoid valve to be de-energized when it receives the solenoid valve de-energizing signal. When the solenoid valve is de-energized, it is suspended in a state of low stiffness and low damping; when energized, it is suspended in a state of high stiffness and high damping.

7. The control system according to claim 6, characterized in that: It also includes a signal judgment module, configured to detect whether the engine speed signal and vehicle speed signal are valid before judging the current state of the vehicle. If both are valid, the enable judgment module is activated; otherwise, the enable judgment module is not activated, and the validity of the engine speed signal and vehicle speed signal is continuously detected.

8. The control system according to claim 7, characterized in that: It also includes a network and power judgment module, configured to not activate the signal judgment module if the vehicle CAN network is abnormal or the vehicle power module is in a closed state before detecting whether the engine speed signal and vehicle speed signal are valid, and to continuously monitor the status of the vehicle CAN network and the vehicle power module. If the vehicle CAN network is normal and the vehicle power module is in a closed state, the signal judgment module is activated.

9. The control system according to claim 6, characterized in that: The enable judgment module is dSPACE.

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