A unified numerical scheme for calculating inverse dynamics of open/closed link mechanisms

In this study, a scheme using the Finite Element Method (FEM) for calculating inverse dynamics is proposed and applied to open- and closed-loop link mechanisms. In this scheme, the entire system is subdivided into discrete elements and evaluated as a continuum. A single-link structure of a pin joint and a rigid bar is expressed by using the Shifted Integration (SI) technique. The proposed scheme calculates nodal forces by evaluating equations of motion in a matrix form, and thus information from the entire system can be handled in parallel. The obtained nodal forces are then used to calculate the joint torque in the system. Simple numerical tests on open- and closed-loop link mechanisms are carried out, and it is verified that the scheme can be used as a unified numerical scheme independent of the system configuration.