Research On Proprioceptive Algorithm For Parallel Motion Simulation Platform Of Construction Vehicles

As engineering vehicles are developing towards large-scale and heavy-duty,motion simulator has become an indispensable test simulation equipment for training drivers and developing vehicles because it has high safety and reliability,and are not limited by external conditions such as weather.As the key technology of motion simulator,the proprioceptive algorithm(also known as washout algorithm)directly determines the fidelity of motion simulation.In this paper,the Stewart platform built in the laboratory is used to study the washout algorithm of the engineering vehicle motion simulation platform,and the simulation and experimental analysis are carried out.Firstly,the freedom,coordinate transformation and inverse kinematics solution of the Stewart platform are analyzed,and the workspace of the platform is calculated,which provides a basis for parameter adjustment of the washout algorithm.Then the sensory mechanism of human body is introduced,and the mathematical models of otolith and semicircular canal are given in the form of transfer function.In the paper,the structure and principle of the classical washout algorithm are introduced,and each link of the washout algorithm is designed.The function of each filter is analyzed,and the order and parameters of all the filters are determined.Simulink is used to build the classical washout algorithm model,and the performance of the classical washout algorithm is analyzed according to the computer simulation.The classical washout algorithm can basically simulate the given acceleration signal and meet the limitat ion of vehicle motion simulation platform.However,due to its fixed parameters,the workspace of the platform can't be fully utilized under complex conditions to provide high fidelity dynamic simulation.Based on the analysis of classical washout algorithm,an adaptive washout algorithm is introduced.The algorithm can adjust the parameters of the filter in real time according to the different input signals to meet the requirements on high performance of dynamic simulation under complex conditions.Considering the effect of dynamic simulation and the limitation of platform motion range,the cost function is established.The stability of adaptive filter is analyzed.Since the output of adaptive filter will diverge with the increase of input signal,the adaptive law is improved to eliminate this defect.In addition,the influence of adaptive weight on adaptive filter is discussed.Finally,the overall structure and control scheme of the simulation platform are introduced.Using the data of driving environment developed by Unity3 D engine,the improved adaptive washout algorithm is experimented.The performances of classical washout algorithm,traditional adaptive washout algorithm and improved adaptive washout algorithm are compared and analyzed.