Numerical Detection of Inactive Joints

Inactive joints are the joints that cannot perform relative motion due to structural limitations in a mechanism. They are usually introduced in order to eliminate redundant constraints. A joint can be inactive in the whole range of the mechanism motion or only in selected configurations. A numerical method of detection of inactive joints is presented. The method is based on multibody system approach and utilizes the constraint Jacobian matrix. The ability to perform relative motion is investigated and inactivity of joints in both regular and singular configurations is discussed. A numerical example is provided.

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