The Effect of Selection of Virtual Variable on the Direct Kinematics of Parallel Mechanisms

摘要

This paper has an interesting observation, i.e., the selection of the loop virtual variable position has an important effect on the direct kinematics analysis of PMs. The correct selection of the virtual variable position will directly affect the effectiveness of solving the direct kinematics of a PM and even affect the form of the direct kinematics. If the virtual variable position is properly selected, the symbolic solutions can be obtained. Otherwise, only closed-form solutions or numerical solutions can be obtained. A one-translation and one-rotation PM as an example is used to derive its symbolic direct kinematics for verification.