Design Optimization And Trajectory Planning Of A 6-DOF Tank Driving Simulator

This research topic is proposed on the basis of the actual project of designing Type 99 tank driving simulator, which is mainly used for training commander, driver and gunner's fighting abilities. The visual system of the 6-DOF tank driving simulator displays the tank movements and posture changes during the tank moves and the motion platform tracks the movement of the virtual tank in real time. The aim is to achieve making a very close to real tank driving environment.This paper presents a six degree of freedom Stewart motion platform based on the actual need, which can do seven degrees of freedom of motions including pitch, roll, rotation, turbulence, translation, yaw and cannon vibration. Firstly, the structural parameters of the parallel mechanism are designed according to the performance indicators. The parameter of the hinge point distribution having greater impact on the drive power is optimized. Secondly, the interference and working space of the hooks is checked corresponding to any angle of the hook under different positions and orientations. Through simulation the result is re-validated and the hook works well. Lastly, In order to ensure the strength and stiffness of the tank driving simulator, the weak dimensions of the hook is optimized by finite element method under alternating load.The tank driving simulator requires smooth movement, little vibration and high real-time. While for parallel mechanism, the trajectory smoothing feature in joint space can not guarantee a smooth trajectory in Cartesian space. This paper proposed a new time-jerk synthetic optimization method for trajectory planning based on Cartesian space of the Stewart parallel mechanism. With the purpose of getting the optimized trajectory, the piecewise cubic spline curve is exploited to interpolate pose series, which is controlled by a set of appropriate constraints such as velocity, acceleration, jerk and time intervals. A real-time method of feasible directions (MFD) is proposed to solve the nonlinear programming problem of optimizing the time interval of the interpolation points. Simulation and experimental results show that the proposed trajectory planning algorithm makes the tank driving simulator track any trajectories given by the visual system smoothly and real-timely.Finally, the control system of the tank driving simulator is designed according to the actual requirement. The coding of the back to position and initial motion module, tank rotation module, tank cannon vibration module and turbulence module is completed. The prototype testing is made showing that the tank driving simulator achieves the performance indicators and meet the requirements of simulating the movement of tanks.