Research On Control System Of "The Frozen" Simulated Skiing Equipment

With the progress of Virtual Reality(VR)technology,the VR industry is getting into a period of rapid development.In response to the call of the Winter Olympic Committee and the State General Administration of Sports,the China Science and Technology Museum proposes to develop a simulated skiing equipment based on the VR technology with the help of digital display board and VR experience.It will make it possible for ordinary people to experience the fun of skiing without needing to go to a ski resort.According to the technical requirement provided by the China Science and Technology Museum,A simulated skiing equipment named "The Frozen" is developed with the help of the VR technology of Crystal Digital Polytron Technologies Inc.This paper introduces the system in the following three aspects:(1)According to the technical requirements by the China Science and Technology Museum,a general layout of the simulated skiing system is designed.Through the theoretical research,the mechanical structure of the system is selected with the aid of the principle knowledge and mechanical design method of the multi degree of freedom parallel mechanism,the dynamic system is derived and established.Then the designs of the control system and the autonomous three degree of freedom meet the requirements of technical specifications.(2)In the servo driver,the system uses inner loop PID control to reduce the position error of the electric cylinder.A BP neural network predicts the pitch angle and the rolling angle of the ski board through the pressure value of the pressure sensor.The mean square error of pitch and rolling angle predicted by the model is 1.20384×10-2,which proves that the prediction ability of the model is good and the model is successfully constructed.The research through the kinematic analysis of the parallel platform method to predict the speed and acceleration of the servo cylinder under different attitude angles are obtained by the prediction of the pitching and rolling angles.The outer loop PID control reduces the position error of the electric cylinder,and makes the angle of the ski board more accurate responding to the angle in VR view.(3)The pressure sensor and servo drive system are calibrated to verify the function and performance of the simulated skiing system.The results show that the maximum error of the pressure sensor is 0.09%,the maximum error of vertical lifting displacement is under 0.28mm,the maximum error of the ski board angle is under 0.09°,and the displacement velocity and angular velocity meet the requirements.Also a test is made to prove the reliability of the system combined with the virtual scene system.The test results show that 91.7%of the experiencers can complete the simulated skiing at their first experiences;with the time of experiences increased,the completion rate is growing and the time for a ski simulation is getting shorter.The system meets the required technical specifications and can be used for virtual skiing.The equipment will be exhibited in the China Science and Technology Museum.