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Modeling and control of constrained flexible joint parallel manipulators

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2010
Oğan, Osman Can
The purpose of the thesis is to achieve a hybrid force and motion control method of parallel manipulators working in a constrained environment, in the presence of joint flexibility that occurs at the actuated joints. A flexible joint is modeled and the equations of motion of the parallel manipulator are derived by using the Lagrange formulation. The structural damping of the active joints, viscous friction at the passive joints and the rotor damping are also considered in the model. It is shown that in a flexible joint manipulator, the acceleration level inverse dynamic equations are singular because the control torques do not have instantaneous effect on the manipulator end-effector contact forces and accelerations due to the flexibility. Implicit numerical integration methods are utilized for solving the singular equations. As a case study, a two legged constrained planar parallel manipulator with three degrees of freedom is simulated to illustrate the performance of the method.