Tracking Algorithms For A Parallel Manipulator

Robotic manipulators are widely used in semi-conductor packaging and assembly industry, and are facing more and more demanding performance indices as the growth of the semi-conductor industry. Considering the complex nonlinearity property of the robot dynamics, using sophisticated nonlinear control theory to robot application and high-precision motion control systems thus become one of the most appealing topics in control literature.The thesis is supported by ASM-HITsz joint laboratory, aiming to design trajectory tracking algorithms for an ASM parallel manipulator. The main challenges of the project are: little knowledge (almost none) about the robot dynamics as none of the mass and link parameters given; joint flexibility and low frequency resonance caused by harmonic drive systems. Adaptive algorithms are of first consideration to deal with unknown parameters, and as to be shown, passivity-based adaptive algorithm is of great superiority to other adaptive ones as its no need to compute the inverse of the inertia matrix, which greatly alleviate the computational load in real-time environment, and its no need of joint angular acceleration measurement, which avoids the high frequency measurement noise appeared in accelerometers. The passivity-based adaptive scheme for ASM manipulator only considers the rigid case tracking control problem because to consider the joint flexibility, we need accurate dynamic model to effectively damp out the joint oscillation, which is rather impossible in the project. Simulation results with fairly good performance are given to demonstrate the feasibility of the scheme.To address the joint flexibility and get some insights to flexile joint robot control, we studied the filtered velocity algorithm scheme for ASM manipulator using its flexible model with assumption that all mass and links are known. In FJR (flexible joint robot) control literature, integral manifold approach, observer approach and back-stepping are the most popular methodologies. They either need accurate dynamic model to cancel nonlinear items or with complex controller structures and despite of the theoretical significance, there are quite few experimental demonstrations in the literature. The...