| With the auto industry development and people's living standards improvement, vehicle safety performance has received special attention, the most important car safety tests—the quality of brake tester will also receive greatly attention, inertial brake test is the most authoritative quality of the test vehicle, which can simulate the real process of the actual braking. Brake tester is a complex system—including the mechanical system, hydraulic and pneumatic systems, cooling systems and dust control system for the central measurement. At present, our country's brake tester's control level and the accuracy of bench test are not high, the key is that data collection is not enough precision, to a large extent, which affected the performance evaluation of the authenticity of brakes. The imported equipment is very expensive. Therefore, the development of independent intellectual property rights of the brake tester has important practical significance.Firstly, the paper introduces the brake test's basic principles and design ideas, the structure of its components, and the software architecture of the brake tester. Which can make us understand the overall structure of brake teter well. In the velocity measurement and control system, According to the requirements of the mechanical rotation speed, the computer convert it into the motor speed, while the computer will control spindle speed through the speed control device, at the same time the speed signal from the motor speed device will be transmited into the motor speed control device. Speed sensor speed signal will be sent into the computer, and based on the difference between the given value to the detected value, the computer will re-adjust the speed, which can form a closed-loop regulation.Brake tester usually use the mechanical inertia flywheel to simulate rotate mechanical inertia, this method can reproduce the situation of brake work, but because of testing machine contains a set of inertia flywheel, which cause a lot of disadvantages, so to research and improve the brake tester become the major hot spots of concern to manufacturers. Through the structure of the brake tester, we can see the system is driven by a DC motor rotating mechanical devices, it is envisaged that if the use of the DC motor speed control system inertia analog part of machine test system,which made the power characteristics like the power characteristics of the original system, then the system will reduce the mechanical inertia flywheels, which will overcome the many shortcomings of the original system. This control technology is electric simulation technology. The use of this technology is not only simple structure, high degree of automation, but also make full use of available resources to overcome the traditional tester's large number of disadvantages, improved the sysytem's accuracy, realized stepless speed regulation system. The reaserch of electric simulation brake tester has important theoretical and practical significance.In view of the original system used DC Lai Him as DC drive motor, and also the speed,current double loop DC Motor Control systems's theory has matured, and the engineering design method is simple and practical. So in this paper, electric simulation system use the DC Lai him as the main drive motor, and the silicon-controlled rectifier devices supply an adjustable voltage, one can study of electric control simulation system based on the dual-Loop DC Motor Control System. Through a certain algorithm to speed so that the output of motor speed could analog the traditional inertia of the output rotational speed, that is the ultimate electric simulation system is based on implementation by means of speed control. The use of the mechanical inertia mix electric simulation can be overcome the disadvantage of simply relying on simple flywheel inertia and the inertia depending on the electric. This simulation used large inertia of the flywheel analog major part of inertia system, and used the electric inertia to accurately adjust, which can achieve stepless adjustment of inertia, reducing the size of the host, but also can reduce the power, at the same time it can lower the capacity of motor and control requirements. The results show that the mechanical inertia mix electric simulation method is feasible and has practical value.In this paper, the research is mainly study about the constant braking torque test. Electric simulation system is a DC motor speed control as the core control system, the variable speed control system is the best form. In the Double Loop DC Motor Control System, in accordance with the engineering design methods, speed loop and current loop should be used PI regulator, and which separately made as I type and II type system to ensure that they were have well follow performance and well disturbance rejection. By comparing the mechanical inertia and double-loop speed control system dynamic equation, we can see that we can realize the electric simulation through changing the voltage of the current loop or speed loop. Taking into account the speed limiter ring design and braking load disturbance, electric simulation control method should be realized by regulating the given voltage of the current loop. To avoid the impact of disturbance which induced by braking torque, based on the traditional double loop system,the electric simulation introduced the braking load disturbance feedforward compensation control to constitute a composite DC speed control system, and set up a system dynamic model structure. Traditional PID control has some characteristics like linear control, simple structure and robustness, Wihich is fit for the mathematical model to determined, the small-disturbance linear system and its implementation is very easy. Brake tester's system is a non-linear,time-varying and hysteresis's electrical fluid complex system. The traditional PID control system can not satisfy the requirements.Fuzzy control has been a hot research of intelligent control, because of its easy control, low-cost implementation, no need to set up mathematical models and other unique advantages, fuzzy control are widely used in a variety of control, especially in the time-varying, non-linear hydraulic control system, which has been widely used. Because in the traditional double loop system the current loop system could improve the system's corresponding speed, it is still being adopted in the current loop PI regulator, which applyed the typical I type systems. While speed loop used the fuzzy controller.Fuzzy controller in the system dynamic performance systems relyed on its error signal, which has less or not impacted by the object model parameters and it has the advantages of realizing high-performance and robustness. Which broke through the limitations of the linear regulator, realized implementation of the speed loop has a smooth saturation control.Finally, One made the experiment on the mechanical inertia mix electric simulation system in the inertia brak tester JF122. Simulation experiments show that the feasibility of the eletric simulation system simulated the original mechanical inertia, and it proved that the introduction of load disturbance feedforward compensation control system has effectively curbed the braking load disturbance, which has a good control performance. And based on the double eletric simulation system model, we can use the Matlab's Simulink toolbox to simulate and analysis the introduction of the fuzzy controller's system. By changing the electric voltage in the current loop, the results show the feasibility of that electric simulation, and it test the effect of introduction the fuzzy controller's control system. |
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