Abstract
A distributed system with interchangeable constraints for studying skillful human movements via haptic displays is presented. A unified interface provides easy linking of various physical models with spatial constraints, and the graphical contents related to the models as well. Theoretical and experimental kinematic profiles are compared for several cases of basic reaching rest-to-rest tasks: curve-constrained motions, flexible object control, and cooperative two-hand movements. The experimental patterns exhibit the best agreement with the optimal control models based on force-change minimization criteria.