Study Of Test Bench Computer Control Based On Auto Brake

Automobile brake design is one of the most important parts of vehicle design. In order to detect the comprehensive performance of the brake, it is necessary to carry on a large number of road tests. However, the road test is not available during the phase of auto design. Therefore, the only way to perform the test is via the special brake test bench. The brake performance test based on the brake test bench provides an effective technical way for the automobile manufacturers and researchers.Generally, the traditional automobile brake test bench utilizes the mechanical inertia which using the flywheel group to carry out brake simulation. In this thesis, the motors are introduced into the test system to compensate the mechanical inertia with electric inertia. Firstly, according to the conditions of the experiment, analyzing the basic structure and the test work flow of test bench, establishing the current control model based on the instantaneous speed of the motor and homeopathic torque which is measurable. Consequently, the motor drive current value in theory is available. Meanwhile, according to four types of different brake mode, a first-order linear damping hysteretic model is established. Using computer program to simulate the model and getting close to the real automobile brake situation as far as possible.Secondly, on the basis of the model, due to the poor stability of the first-order linear damping hysteresis model, establishing a closed-loop control system model based on closed loop control theory. The simulation result is obtained by computer simulation. And according to energy error analysis and feasibility verify, this model effectively improves the stability and anti-interference. However, according to the actual brake performance requirements, the accuracy of the model is expected to be improved.Finally, due to the measurement discontinuous of the closed loop control system, establishing the model based on the electromagnetic induction and the DC transformer principle to improve the structure of the original system and optimize the device and the circuit control. Based on the theoretical analysis and calculation, the simulation is carried out on the basis of the original model, which reduced the system error from 5.7%to less than 2%. The validity and feasibility of the model are verified by error analysis effectively.The innovations of this thesis are as follows:1. The traditional brake test bench only simulates the working process of brake under the braking force which is constant. In this thesis,4 kinds of brake work modes are simulated by computer program. Therefore, the test is closer to the real road test;2. According to the observable variables discretization of drive current model which cause the system error. The electromagnetic induction and DC voltage principle are used in this thesis to improve the original model. It effectively reduces the system error and improves the accuracy of the test.