Stochastic Optimal Control of Nonlinear Suspension of Quarter Car Model
|School||Nanjing University of Aeronautics and Astronautics|
|Keywords||Nonlinear Suspension Random Vibration Equivalent linearization Stochastic optimal control Monte-Carlo method|
Suspension system performance will directly affect the vehicle's ride comfort and handling stability . Because of its traditional passive suspension parameters fixed , resulting in a fundamental cause of both conflicts. Active suspension according to real working conditions , to produce the desired control of the suspension , the suspension is in the optimum damping state. Therefore, this study of random vibration control of vehicle suspension , focusing on analysis with nonlinear damping and spring hysteresis characteristics of 1/ 4 vehicle suspension nonlinear random vibration response , and its conduct in stochastic optimal control under different conditions . This paper studied the single degree of freedom suspension smooth and non-stationary responses. Equivalent linearization method introduced the basic ideas and their application in nonlinear systems . Consider the case of the tire contact with the ground , the road space white noise random excitation is considered the second-order filter output . Analysis of the nonlinear factors and linear passive suspension damping ratio for fixed speeds in the case of stationary random response of the impact of stochastic optimal control theory based on the design of infinite time stochastic optimal control law for the various active and passive suspension performance analysis and comparison . Subsequent studies of a single degree of freedom suspension due to the speed variations or mutations in non-stationary excitation random response analysis of nonlinear factors and linear passive suspension damping ratio for non-stationary response of the designed finite time stochastic optimal control law , and active and passive suspension performance comparison. Subsequently, the equivalent linearization method is extended to two degrees of freedom suspension system, road roughness as a first-order spatial filtering white noise stable output. Analysis of the weight coefficients for fixed speeds active suspension performance under the influence , from the comfort point of view, select an appropriate set of weighting coefficients for active and passive suspension performance compared. Studied the active control vehicle speeds make up reasons such as brake uniform deceleration to stationary response of non-stationary , and its active control . Finally, Monte-Carlo simulation method for two degree of freedom nonlinear suspension uniformly accelerated numerical simulation carried out to verify the feasibility of the equivalent linearization method and accuracy .