Multibody Dynamics Approaches to Biomechanical Applications to Human Motion Tasks

Applications of multibody dynamics or control to human mobility, impact biomechanics, ergonomics or health and medical cases require that reliable models of human body, including all relevant anatomical segments and a representation of the musculoskeletal system, are developed. The system state variables are available either to a control algorithm or to appraise the internal forces or even to evaluate performance indexes associated to the particular task. Here, a biomechanical model of the human body is presented and applied to demonstrate the basic modeling requirements. A strategy for the control of the biomechanical model motion, based on a distributed hierarchical control, is proposed. The biomechanical model is used to study zero momentum maneuvers, such as those of an astronaut in space or of a high-platform diver. Recognizing that the internal driving forces in the human body result from the musculoskeletal system and not from torque actuators, a procedure to evaluate the muscle forces is presented. Muscle activation dynamics models and optimization techniques are part of the proposed methodology. A human locomotion task demonstrate the procedure and to show the relation between muscle forces and the joint torques used in the control model.