Study On Implementation Method Of Testing Systems For Suspension Dynamic Performance

In the history of the development of the vehicle, buffer, stability and vibration have been essential factors for restricting its advance.The suspension system is the key of solving these problems. At present, the majority of the test board for suspension dynamic characteristics are still the mechanical testbed in our country, its main disadvantage is single function, can not fully meet demand of the suspension testing system, and test accuracy is directly influenced by structure of incentive system. Focusing on the theme of testing systems for vehicle suspension dynamic characteristics and drawing on research achievements at home and abroad, using the principle of multi-body system dynamics, this thesis develops a test bed of suspension dynamic characteristics based on the hydraulic servo control system. The theoretical analysis and simulation is preformed in this thesis as well.Full text firstly illustrates the necessity and practical meaning of self-developed test equipment for suspension dynamic characteristics. It also introduces domestic and foreign research achievements in this field.Secondly mechanism of the test bed is constructed, which is based on the test requirements of the vehicle suspension dynamic characteristics. The testing system for vehicle suspension dynamic characteristics is also designed as a size of1/4vehicle. To build complete hydraulic servo control system, this testing system includes the design of the main components such as hydraulic cylinders, servo electromagnetism valve, sensors, etc. and determining the connection between them.Then following the system and transmission characteristics of every link of the system, this chapter describes the equations of motion of the corresponding link. The total transfer function of the testing system is gained with the control theory of knowledge. Finally, on using MATLAB a numerical simulation is taken for the entire control system to achieve the best results.Under the actual condition of suspension, the step signal,the sinusoidal signal,the square signal are applied to the vibrating actuator. Then PID and fuzzy PID control algorithm are selected respectively to control the output.The results showed that:compared with the without control algorithm and join PID control, the fuzzy PID control system which is for sake of making the output have better synchronization with the input. The excitation of the excitation units can better simulate the road, thereby improving the accuracy suspension dynamic characteristics of the test.Finally, the use of virtual instrument Labview graphical programming language to build a test and analysis system, reducing hardware testing process, to achieve the same purpose for the suspension dynamic characteristics of the test signal real-time acquisition, processing and analysis.The main innovation of this paper:the other one is the test bench mechanical structure design, the unsprung mass and the sprung mass considered separately. This design can be quantitatively simulate different suspension and models, so that the test results closer to the actual situation. Secondly in the design of excitation control system platform, adding a PID and fuzzy PID control algorithm, so exciting platform simulation accuracy greatly improved.