Simulation Study Of Caterpillar Vehicle Active Suspension

The suspension system is one of the important devices of the vehicle. It is to ensure that the wheel or axle with the vehicle carrying the system, such as frame(or unibody) contact between the flexible and to be able to transfer load, impact and vibration, and attenuation and adjust the vehicle traveling in the general body location of the device. The suspension is helpful to enhance smooth running, operation stability of the vehicle and the life of assembly. On the other hand, the excellent suspension can help us to get better fuel economy.the program is from the China North Industries Group Corporation—Northern Special Vehicle Co. LTD in Harbin. The task is that we need to design the active suspension which is helpful to enhance smooth running, operation stability of the vehicle and the life of assembly.Below is the main job and achievement of the dissertation:1) Suspension for a brief overview to introduce the main role of suspension, respectively, the concentration of suspension described categories:passive suspension, semi-active suspension, active suspension. Reviewed several active suspension control method, and for decades a large number of foreign scholars in the field of active suspension design made remarkable achievements. Introduced the purpose and significance of the research project, and briefly describes the design. 2) Describes a general evaluation of performance suspension, and briefly lists the usual method of vehicle suspension model:a single wheel 2-DOF, two wheels 4 DOF, four-wheel-7 DOF model. Describes the frequency of road space and time frequency power spectral density power spectral density, and the relationship between the two, the establishment of a random road test model. After the research vehicle combining the characteristics of the tracked vehicle model is appropriate simplification, were established semi-passive suspension and active suspension car,8 degrees of freedom model. And use of modern control theory, system state equation and output equation, find the correlation matrix.3) The introduction of random linear optimal regulator theory (LQR), and its expansion, describing the relevant reference, a brief review of the linear optimal regulator theory of several types. About observability optimal control theory and controllability of the content and gives the judge the paper observability and controllability for the approach. Then, around the research topic, describes the tracked vehicle active suspension optimal controller design, and details of the relevant parameters of the solution matrix is presented for solving the optimal control method.4) By using matlab-simulink computer simulation software, combined with the design of random linear optimal control strategy for active suspension of vehicles tracked in computer simulation. in order to get more directly with observations, the author of the passive suspension and active suspension to simulate the same time, in the same road input and other objective condition, has been passive suspension and active suspension of the curve out to prove that the active suspension can effectively improve the vehicle's driving safety and running comfortably. Secondly, in order to determine the weighting factor on the use of optimal control design of active suspension, the author has been adjusted appropriately weighted factors to get the output after the change curve. In contrast to the active suspension parameters before change in the curve, we can draw weighting factors influenced on the optimal control scheme.