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The purpose of this paper is to design a wavelet neural network self-tuning proportional-integral-derivative (PID) controller for solving the problem of fast changing payload in a linear motor in the 6-DOF platform system. The wavelet neural network PID controller demonstrates the special capabilities of fast response and self-tuning. A practical system identification method is proposed to identify the dynamic model of a linear motor by using the balancing realization theorem and inverse discrete Fourier transform. The experimental results of the real-time software simulation and hardware-in-the-loop simulation demonstrate the novel ability of self-tuning PID controller for adapting the quick load change in the forcer of linear motor, which activates the platform system. 

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The purpose of this research is to improve the motion-cueing fidelity of the simulator by using fuzzy-tuning technique to tune the parameters of washout filter in real-time.In order to enhance the motion-cueing fidelity within the limited working space on simulator, the limited working space and the frequency of input dynamic signal must be taken into account for the parameter adjustment of washout filter. The main frequency of input dynamic signal has been abstracted by using Discrete Fast Fourier Transform (DFFT) technique to tune the parameter of the adaptive washout filter. The experimental result demonstrates the error of motion cueing is not perceptible.In the mean time, we have employed a single CCD camera to measure the attitude of the Stewart platform in real time for feedback control. The measured attitude of the moving platform is almost exactly as same as the input driven signal.

This paper presents the optimal mechanism design and dynamic analysis of a prototype 3-leg 6-DOF (degree-of-freedom) parallel manipulator. Inverse kinematics, forward kinematics, inverse dynamics and working space characterizing the platform motion are derived. In the presented architecture, the base platform has three linear slideways individually actuated by a synchronous linear servo motor, and each extensible vertical link connecting the upper and base platforms is actuated by an inductive AC servo motor. The linear motors contribute high-speed movements to the upper platform. This kind of architecture using hybrid (linear and AC) motors yields high level performance of motions, especially in the working space. The novel result of maximal working angles is the significant contribution of this architecture. The Taguchi Experimental Method is applied to design the optimal mechanism of the platform system, and the result is used as the actual data to build this system.