Abstract

The challenge for many biomechanics researchers who develop computer simulation models of human motion is to provide evidence that their model is a valid one. If this validation can be done in an interactive manner, then the simulation model has that much more impact. The purpose of the present study, therefore, was to set up the necessary environment for interactive validation of certain simulation models of human movement. We chose as our model of human movement the planar double pendulum. The equations of motion for this mechanical phenomenon are well known and lend themselves very conveniently to simulation on a digital computer. The action of the double pendulum can be used to model the motion of various human movement activities. We set up the following two experiments: a digital camera system, capable of providing immediate feedback of kinematic data, was used to track the motion of (a) a simple double pendulum consisting of two links with known inertial characteristics swinging under the influence of gravity alone; (b) a person performing a swinging action with markers placed over the shoulder, elbow and wrist joints. We were able to demonstrate good agreement between theory and actual collected data. Armed with this success we could then go ahead and perform simultions and use these to predict the torques generated at the shoulder and elbow joints. The interactive validation of our dauble pendulum model was fcilitated by two vital pieces of hardware: IBM PC/AT and the digital camera system. We have found that our system has the greatest impact in teaching and demonstrating computer simulation techniques to students. Verf.-Referat