Study On Adaptive Control Techniques Of Vehicular Vibration Isolation Platform

In order to ensure the normal operation of the vehicle instrumentation,the vehicle platform carrying the instrument must achieve vibration isolation.In this paper,the Stewart platform is used as the vibration isolation platform,and the platform is isolated by active and passive vibration isolation.The vibration isolation effect of the adaptive algorithm in active control is studied.The main work is as follows:Determine the overall vibration isolation Scheme of the platform.The Stewart platform is used as the vibration isolation platform,the air spring is the passive vibration isolation element,the voice coil motor is the actuator,the hinge joint is the hinge,the acceleration sensor is the signal acquisition device,and the adaptive algorithm is the active control algorithm.We Analyzed the interference frequency range,have set the payload quality,the natural frequency of the platform,the introduction of various types of devices and selection and so on.The platform dynamics equation is established,the Stewart platform configuration of the six struts is determined,and the decoupling control is analyzed.About platform degrees of freedom,yx-q,xy-q,z,zq four groups are completely independent,that is,X-axis translational and Y-axis rotation direction coupling,X-axis rotation and Y-axis translational direction coupling,other degrees of freedom completely independent.The payload centroid only needs to be on the extension of the vertical axis of the platform without the need to be installed at a specific location,reducing the installation requirements.Decoupling control makes the control channel on the algorithm can be independently controlled,easy to follow-up simulation and debugging.The working principle of LMS adaptive algorithm is deduced in detail.The convergence conditions,convergence speed,steady-state error and computational complexity of LMS adaptive algorithm are given.The simulation results show that the comb-like structure adaptive algorithm is better than the transverse structure adaptive algorithm for the simple harmonic excitation.The simulation results show that the comb-like structure adaptive algorithm is better than the transverse structure adaptive algorithm.Aiming at the contradiction between convergence rate and steady state error in adaptive algorithm,a variable step size adaptive algorithm is adopted,which makes the algorithm get faster convergence rate and smaller steady state error.The environment of the vehicle platform simulation is MATLAB/Simulink,and feedback of the platform is acceleration.Because the platform is mainly disturbed by simple harmonics,the platform is simulated by the adaptive algorithm with variable step length comb structure.The simulation results show that the passive vibration isolation rate of the designed vibration isolation platform is 0.004 ~ 0.7848,and the Z axis rotational direction is the highest.The active control vibration isolation rate is 62%~86%.At the same time,the vibration isolation effect of the step-size algorithm and the variable-step algorithm is compared.The simulation results show that the variable-step algorithm is superior to the step-length algorithm for the six degrees of freedom of the platform.