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Abstract
A study of the kinematic characteristics of a three degree-of-freedom (dof) parallel mechanism is presented. The architecture of the mechanism is described. The inverse diaplacement and inverse velocity solutions are obtained. Since the mechanism has only three dof, constraint equations describing the inter-relationship between the six motion coordinates are derived. These constraints allow the definition of parasitic motions, i.e., motions in the three unspecified motion coordinates. When incorporated into the kinematics model, the constraints allow a constrained Jacobian matrix to be obtained. A dexterity analysis is undertaken, and an analysis of the dexterous workspace of the mechanism is also reported. Architecture optimization of the device is undertaken demonstrating that specific values of design variables allow minimization of parasitic motion and optimization of dexterity. Finally, static force solutions are formulated to allow required actuator and structural forces to be determined.
