Research on the control system of the static stabi

Research on the control system of vehicle static stability test-bed

Abstract: research the control system of vehicle static stability test-bed, and realize the measurement of vehicle centroid position, wheel mass, axle mass, total mass, lateral stability

angle determination, etc. From the perspective of computer control, the system analysis is carried out, the structural scheme of the test-bed control system is proposed, and the numerical calculation process and the control process of the roll angle

are given

vehicle static stability parameters include vehicle centroid position and height, roll stability angle and other parameters, which are important indicators affecting vehicle handling stability, vehicle ride comfort and vehicle safety. China's national standard clearly stipulates that the maximum roll stability angle of the vehicle tilting to the left and right shall not be less than 35 degrees under no-load and static conditions

and the position and height of the vehicle's centroid are directly related to the roll stability angle. At present, these static stability parameters of vehicles are mostly determined by the test bench. The test bench studied in this paper meets the "GB/t14172 vehicle static rollover bench stability test method", which can complete the measurement of vehicle centroid position (three-dimensional coordinates), wheel mass, axle mass, total mass and roll stability angle

1. Analysis of the structure and control function of the test bench

the system structure of the vehicle static stability test bench is mainly composed of a 2-DOF parallel plane 3 experimental machine, which should be reasonably arranged, beautiful in appearance, simple in operation, convenient for maintenance and computer measurement and control system. Among them, the 2-DOF parallel platform is composed of a movable

movable platform and a hydraulic cylinder (represented by an ellipse in the figure) connected by Hooke hinges. Under the control of the computer measurement and control system, it can realize the pitch and roll two degrees of freedom

movement, and complete the measurement of vehicle centroid position and roll stability angle respectively. Specific measurement steps and control analysis are as follows:

(1) the vehicle aligns the front wheel through the roll alignment mechanism. The rolling alignment mechanism needs to control the rolling movement of two rollers, and two ordinary motors are used to drive the rollers to realize

rolling

(2) pull the vehicle to the measuring platform through the traction mechanism. The vehicle traction is realized by controlling the winch on the traction mechanism. The traction speed shall be slow and stable

the start and stop control of traction can be carried out. The process control of traction is realized by using frequency converter to control three motors

(3) when it was the turn of the wheel weighing block that pulled each axle as early as the beginning of 2004, the traction was stopped, and the wheel weight was measured by three weighing sensors placed under the wheel weighing block. The signal of the sensor is transmitted to the industrial computer through the data acquisition card, and the data calculation and display are realized

(4) after towing the last axle to wheel weighing block of the vehicle, complete the wheel weight measurement of all wheels to obtain the axle weight and total weight. When the global car ownership increases, the wheel position of the last

axle is recorded through the positioning device, and the position coordinates of each wheel relative to the wheel on the last axle are calculated through the wheel base and wheel base of the vehicle

(5) the movement of the hydraulic cylinder is controlled by the computer control system to realize the forward and backward inclination of the measuring platform, and the measurement of the centroid position is completed by the change of the measuring force of the wheel weighing and the weight measuring block and the measured value of the angle sensor

(6) the movement of the hydraulic cylinder is controlled by the computer control system to realize the left and right roll of the measuring platform. When the weighing of one side wheel and the measuring force of the weighing block are zero, the measured value of the angle

degree sensor is the roll angle. And in the process of measuring the roll angle, it is necessary to detect whether the anti rollover mechanism starts to work through the position switch

2. Control system framework

according to the above requirements, the control system of this test-bed needs to complete the quality and angle data measurement, hydraulic drive control, system protection, logic control and the working state of the monitoring system. The composition of the system, the man-machine interface receives the wheel base, wheel base, model and other parameter information of the vehicle, and transmits it to the industrial computer for numerical calculation

display the calculation and monitoring results, such as wheel weight, axle weight, total weight, centroid coordinates, pitch angle and other result data provided to the customer. Industrial computer is the plastic of this test-bed. According to its use, it can be classified into engineering plastics, general plastics and special plastics

control center to realize interaction with human-computer interface; Receive the data of the weighing sensor after a/D conversion through the data acquisition card and the position coordinates of the positioning system, and obtain the measurement results through numerical calculation, and display them through the human-machine interface; Control the test-bed system to measure and monitor the working state of the system. External

control includes the power on control of the motor of the rolling mechanism, the overturning movement of the test platform is realized by driving the servo hydraulic cylinder through the motion control card, the control of the traction motor and the detection of the working state of the

anti rollover mechanism

3. Measurement and control process of roll angle

the measurement of roll angle is the measured value of the angle sensor obtained by controlling the left and right roll of the test bench when the pressure of one side of the wheel set platform is zero. The computer

control system completes the measurement process as follows:

(1) control the traction mechanism to pull the afternoon vehicle to the central position of the test bench, so that its longitudinal center is flat and parallel to the rotation center line of the test bench

(2) implement the parking brake, install the stop to prevent side sliding, the device to prevent longitudinal movement and steering handle rotation, and the safety protection device to prevent overturning, so that the tested

will no longer produce side sliding, the meridian wheel will no longer produce longitudinal movement, and the steering handle will no longer produce rotation, and through the position detection switch, detect the working state of each device to ensure the safety of the test

(3) the control system drives the servo hydraulic cylinder through the motion control card to realize the tipping movement of the test platform, making the platform tilt slowly to the left. With the increase of the tilt angle of the test table

, the force changes of the right wheel weighing 2 and the weight measuring block 2 are read continuously until the measured force is zero, and the value of the angle sensor installed on the top of the hydraulic cylinder is obtained.

is the measurement of the maximum left roll stability angle. In the process of controlling the movement, with the increase of the inclination and the decrease of the force on the right wheel weighing 2 and the weight measuring block 2, the control speed

decreases steadily to zero

(4) drive the servo hydraulic cylinder through the motion control card to restore the tilted test bench to 0 ° and complete the measurement. The measurement procedure of the right maximum roll stability angle is the same as above

4. Conclusion

based on the analysis of the action process of the afternoon vehicle static stability test-bed, this paper puts forward the structural scheme of the test-bed control system, gives the numerical calculation process and the control process of the roll angle, and realizes the measurement of the vehicle center of mass position, wheel mass, axle mass, total mass and roll stability angle. However, there is no further analysis of the system error in this paper, so it is necessary to conduct in-depth research on the system error in order to improve the accuracy of the system