Method for estimating the ride height of a dynamic vehicle suspension

Abstract

The present application belongs to the technical field of vehicle suspension, and particularly relates to a method for estimating the suspension height of a vehicle in dynamic driving; and specifically comprises the following steps: recording the pressure of each suspension when the vehicle is at rest; establishing an array for storing displacement data; collecting the output signals of each suspension displacement sensor; calculating the displacement of each suspension; recursively moving the array elements and storing the latest data; collecting the output signals of each suspension pressure sensor; calculating the pressure of each suspension; comparing the current pressure of each suspension with the recorded pressure; judging the current motion state of each suspension and recording the same respectively; and estimating the suspension height; the present application calculates the height of each suspension by using a displacement sensor and the pressure of each suspension by using a pressure sensor, and estimates the actual height of the vehicle suspension in dynamic driving by using a height estimation algorithm.

Description

Technical Field

[0001] This invention belongs to the field of vehicle suspension technology, specifically relating to a method for estimating the suspension height of a dynamically moving vehicle. Background Technology

[0002] Currently, vehicles have increasingly higher requirements for off-road capability and suspension adaptability, leading to a growing demand for height-adjustable suspensions. During driving, the suspension height changes in real-time with variations in road surface inputs. However, during suspension height adjustment, it's impossible to determine whether the displacements of each suspension element are equal, resulting in significant vehicle tilt after adjustment, impacting driving safety and ride comfort. Therefore, adjustable suspension systems require adjustments to a stationary position to ensure vehicle stability. While adjusting the suspension height for different road conditions improves off-road capability, driving experience, and fuel economy, each adjustment requires stopping the vehicle and then continuing to drive. This increases driving time and the complexity of using the suspension height adjustment function, preventing the full realization of the advantages of adjustable suspension. Summary of the Invention

[0003] (a) Technical problems to be solved

[0004] The technical problem to be solved by this invention is: how to estimate the various suspension heights of a vehicle during dynamic driving.

[0005] (II) Technical Solution

[0006] To address the aforementioned technical problems, this invention provides a method for estimating the suspension height of a dynamically moving vehicle, comprising the following steps:

[0007] Step S1: Record the pressure of each suspension element when the vehicle is stationary;

[0008] Step S2: Create an array to store the displacement data;

[0009] Step S3: Real-time acquisition of output signals from each suspension displacement sensor;

[0010] Step S4: Calculate each suspension displacement based on the output signal from step S3;

[0011] Step S5: Recursively move array elements and store the latest data;

[0012] Step S6: Collect the output signals of each suspension pressure sensor;

[0013] Step S7: Calculate each suspension pressure based on the output signal from step S6;

[0014] Step S8: Compare the current pressure of each suspension with the recorded pressure;

[0015] Step S9: Determine and record the current motion state of the suspension.

[0016] Step S10: Estimate the suspension height.

[0017] In step 1, when the vehicle is powered on and stationary, the suspension is in a balanced state. The analog values ​​output by the pressure sensors of each suspension are read and converted into digital values ​​through the analog-to-digital conversion module. The actual pressure values ​​of each suspension are calculated based on the actual parameters of the sensors and the measurable physical range. The calculated pressure values ​​are the pressure values ​​under the balanced state of the suspension and are saved for subsequent calculations.

[0018] In step 2, an array of N elements with a total of 3 elements is created (N is the number of vehicle suspensions) to store the physical data of the actual suspension displacement collected and calculated by the displacement sensor.

[0019] In step 3, the analog signals output by each suspension displacement sensor are collected in real time, and the analog signals are converted into digital signals through the analog-to-digital conversion module.

[0020] In step 4, the data processed in step 3 is read, and the actual displacement of each suspension is calculated based on the actual parameters of the sensor and the measurable physical range, and saved for subsequent calculation.

[0021] In step 5, the first element of the array established in step 2 for storing the corresponding suspension displacement data is removed from the array, the second element is moved to the position of the first element, and the third element is moved to the position of the second element. The displacement data calculated in step 4 is then stored in the position of the third element of the array.

[0022] In step 6, the analog signals output by the pressure sensors of each suspension are collected in real time, the analog signals are converted into digital signals through the analog-to-digital conversion module, and abnormal signals are removed by software filtering before being saved for subsequent calculations.

[0023] In step 7, the data processed in step 6 is read, and the real-time actual pressure of each suspension is calculated based on the actual parameters of the sensor and the measurable physical range, and saved for subsequent calculation.

[0024] In step 8, during the selection of the preset value for the difference range, selecting a preset value that is too large leads to a large error and cannot accurately reflect whether it is at a balanced position; selecting a preset value that is too small places high demands on the sensor and the controller's acquisition requirements, and the signal is easily affected by interference, generating random errors and also failing to accurately reflect whether it is at a balanced position. After analyzing the pressure and displacement data of the 1 / 4 vehicle suspension test bench under random road surface excitation, a preset value of 0.1 MPa can effectively balance the error and accuracy requirements. Therefore, a difference value of 0.1 MPa is selected. The actual pressure data of each suspension saved in step 7 is read and compared with the pressure data saved in step 1. When the difference between the pressure data in step 7 and the pressure data saved in step 1 is less than 0.1 MPa, the displacement data stored in the third element of the array in step 5 is read from the test bench data and saved for later retrieval.

[0025] Based on the characteristics of the suspension, when the suspension pressure is at the equilibrium position, the suspension displacement should be the actual displacement when the vehicle is stationary. The displacement data obtained in step 8 represents the displacement at the moment when the suspension pressure is at the equilibrium position, and therefore can be used as the actual suspension displacement.

[0026] In step 9, based on the characteristics of the suspension, the frictional force is different during compression and extension. To eliminate the impact of different frictional forces on height estimation, it is necessary to determine whether the suspension is currently in a compression or extension process. The third element of the suspension displacement data stored in step 5 is read. If the displacement data of the third element is greater than the displacement data of the second element, and the displacement data of the second element is greater than the displacement data of the first element, then the suspension is currently in an extension process. If the displacement data of the third element is less than the displacement data of the second element, and the displacement data of the second element is less than the displacement data of the first element, then the suspension is currently in a compression process.

[0027] In step 9, when the suspension is in a stretched state, the displacement data stored in the third element position of the array in step 5 is read and recorded as H1; when the suspension is in a compressed state, the displacement data stored in the third element position of the array in step 5 is read and recorded as H2.

[0028] In step 10, the estimated dynamic suspension height is denoted as H, and H = (H1 + H2) / 2. The suspension height calculated using the above formula can eliminate the influence of different friction forces on the suspension height estimation.

[0029] (III) Beneficial Effects

[0030] 1. Compared with the prior art, the dynamic driving vehicle suspension height calculation method of the present invention is mainly used for calculating the suspension height of vehicles equipped with adjustable suspension height systems during dynamic driving.

[0031] 2. Compared with the original method of calculating dynamic suspension height by filtering direct displacement data or by collecting extreme values ​​from displacement data, the method proposed in this invention can more accurately calculate the actual suspension height of the vehicle during dynamic driving, making it possible to precisely adjust the suspension height during vehicle driving.

[0032] 3. This invention extends the operating conditions for suspension adjustment from the original static or paved road conditions to any vehicle and road condition, greatly expanding the application scenarios of adjustable suspension.

[0033] 4. This invention can ensure the stability of the vehicle body when adjusting the suspension height, so that the suspension can bring better passability, driving experience and fuel economy, and maximize the advantages of adjustable suspension. Attached Figure Description

[0034] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0035] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0036] To address the aforementioned technical problems, this invention provides a method for estimating the suspension height of a dynamically moving vehicle, such as... Figure 1 As shown, it includes the following steps:

[0037] Step S1: Record the pressure of each suspension element when the vehicle is stationary;

[0038] Step S2: Create an array to store the displacement data;

[0039] Step S3: Collect the output signals of each suspension displacement sensor;

[0040] Step S4: Calculate the displacement of each suspension element;

[0041] Step S5: Recursively move array elements and store the latest data;

[0042] Step S6: Collect the output signals of each suspension pressure sensor;

[0043] Step S7: Calculate the pressure of each suspension element;

[0044] Step S8: Compare the current pressure of each suspension with the recorded pressure;

[0045] Step S9: Determine and record the current motion state of the suspension.

[0046] Step S10: Estimate the suspension height;

[0047] In step 1, after the vehicle is powered on, the parking brake signal and vehicle speed signal are read. When the parking brake signal is valid and the vehicle speed signal is 0 km / h, it can be determined that the vehicle is in a stopped state and the suspension is in a balanced state. The analog signals output by the pressure sensors of each suspension are read and converted into digital signals by the analog-to-digital converter. According to the formula: Actual pressure = (Current sampled value - Minimum sampled value) * (Maximum range) / (Maximum sampled value - Minimum sampled value), the current actual pressure value of each suspension is calculated. The calculated pressure value is the pressure value under the suspension balance state, denoted as P. a0 P b0 P c0 P d0 Waiting for subsequent calculation calls.

[0048] In step 2, the vehicle has 4 suspensions, and an array H with 3 elements is created. a [3] H b [3] H c [3] H d [3] is used to store the actual displacement physical quantity data of the suspension collected and calculated in real time by the displacement sensor. Whenever the first element of the array is removed from the array, the second element is moved to the position of the first element, and the third element is moved to the position of the second element. The latest displacement data is stored in the position of the third element of the array.

[0049] In step 3, the analog signals output by each suspension displacement sensor are collected in real time, and the analog signals are converted into digital signals through the analog-to-digital conversion module.

[0050] In step 4, the data processed in step 3 is read, and the actual displacement of each suspension is calculated according to the formula: actual displacement = (current sample value - minimum sample value) * (maximum range) / (maximum sample value - minimum sample value), and saved for subsequent calculation.

[0051] In step 5, the first element of the array established in step 2 for storing the corresponding suspension displacement data is removed from the array, the second element is moved to the position of the first element, and the third element is moved to the position of the second element. The displacement data calculated in step 4 is then stored in the third element position of the array, i.e., H. * [3]

[0052] In step 6, the analog signals output by the pressure sensors of each suspension are collected in real time, the analog signals are converted into digital signals through the analog-to-digital conversion module, and abnormal signals are removed by software filtering before being saved for subsequent calculations.

[0053] In step 7, the data processed in step 6 is read, and the real-time actual pressure value of each suspension is calculated according to the formula: Actual pressure = (Current sampled value - Minimum sampled value) * (Maximum range) / (Maximum sampled value - Minimum sampled value), and denoted as P. a P b P c P d Waiting for subsequent calculation calls.

[0054] In step 8, the actual pressure data of each suspension element saved in step 7 is read and compared with the pressure data saved in step 1. When the difference between the pressure data in step 7 and the pressure data saved in step 1 is less than 0.1 MPa, i.e. |P * -P *0 When |<0.1Mpa, read the displacement data H stored at the 3rd element position of the array in step 5. * [3] and save this displacement data for later use.

[0055] Based on the characteristics of the suspension, when the suspension pressure is at the equilibrium position, the suspension displacement should be the actual displacement when the vehicle is stationary. The displacement data obtained in step 8 represents the displacement at the moment when the suspension pressure is at the equilibrium position, and therefore can be used as the actual suspension displacement.

[0056] In step 9, based on the characteristics of the suspension, the frictional force is different during compression and extension. To eliminate the impact of different frictional forces on height estimation, it is necessary to determine whether the suspension is currently in a compression or extension process. The data H representing the suspension displacement stored in step 5 is then read. * [3], if H * [3]>H * [2]>H * [1], then it is determined that the current suspension is in the stretching process; if H * [3] <H * [2] <H * [1], then it is determined that the current suspension is in the compression process.

[0057] In step 9, when the suspension is in a stretched state, the displacement number H stored in step 5 is read. * [3] Recorded as H *1 When the suspension is in a compressed state, read the displacement data H stored in step 5. *[3] Recorded as H *2 .

[0058] In step 10, the estimated dynamic suspension height value is denoted as H. * Then H * =(H *1 +H *2 The suspension height calculated using the above formula can eliminate the influence of different friction forces on the estimation of suspension height, and accurately calculate the suspension height of a dynamically moving vehicle.

Claims

1. A method for estimating the suspension height of a dynamically moving vehicle, characterized in that, It includes the following steps: Step 1: Record the pressure of each suspension element when the vehicle is stationary; Step 2: Create an array to store the displacement data; Step 3: Collect the output signals of each suspension displacement sensor in real time; Step 4: Calculate each suspension displacement based on the output signal from Step 3; Step 5: Recursively move array elements and store the latest displacement data; Step 6: Collect the output signals of each suspension pressure sensor; Step 7: Calculate each suspension pressure based on the output signal from Step 6; Step 8: Read the actual pressure data of each suspension saved in Step 7, compare the actual pressure data with the pressure data saved in Step 1, and when the difference between the pressure data in Step 7 and the pressure data saved in Step 1 is less than 0.1 MPa, proceed to Step 9. Step 9: Determine the current motion state of the suspension. When the suspension is in the extension process, read the latest displacement data stored in the array in Step 5 and record it as H1; when the suspension is in the compression process, read the latest displacement data stored in the array in Step 5 and record it as H2. Step 10: Estimate the suspension height. Record the estimated dynamic suspension height value as H, then H = (H1 + H2) / 2.

2. The method for estimating the suspension height of a dynamically moving vehicle as described in claim 1, characterized in that, In step 2, an array of N elements with a total of 3 elements is created, where N is the number of vehicle suspensions, to store the real-time suspension displacement physical quantity data collected and calculated by the displacement sensors.

3. The method for estimating the suspension height of a dynamically moving vehicle as described in claim 1 or 2, characterized in that, In step 5, the first element of the array used to store the corresponding suspension displacement data established in step 2 is removed from the array, the second element is moved to the position of the first element, and the third element is moved to the position of the second element; the displacement data calculated in step 4 is stored in the position of the third element of the array.

4. The method for estimating the suspension height of a dynamically moving vehicle as described in claim 3, characterized in that, In step 9, the third element of the array storing suspension displacement data in step 5 is read. If the displacement data of the third element is greater than the displacement data of the second element and the displacement data of the second element is greater than the displacement data of the first element, it is determined that the current suspension is in the stretching process; if the displacement data of the third element is less than the displacement data of the second element and the displacement data of the second element is less than the displacement data of the first element, it is determined that the current suspension is in the compression process.

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