Interactive Modeling and Analysis of Open or Closed Loop Dynamic Systems with Redundant Actuators

This paper deals with the development of a computer-based procedure for the modeling and analysis of large displacement dynamic systems of the open or closed loop types. The procedure facilitates the construction of the model for such systems, automatically formulates the dynamic equations and provides the solution for any given input motion. The program is capable of analyzing complex systems with redundant force actuators utilizing a linear programming optimization scheme. It incorporates an interactive graphic capability which is invaluable in the construction, modification and visual checking of a model. The modeling procedure is general in nature and is applicable to systems of many connected rigid bodies. Its capabilities are illustrated in this paper by evaluating muscle forces and joint reactions of the musculoskeletal structure during dynamic activity. The system is readily applicable to the analysis of the actuation schemes in human and animal locomotion, many classes of machine systems, as well as robots and manipulators. Although only applications to open loop mechanisms are presented in this paper, the program can be readily extended to treat closed loop systems as well.