Trajectory Guidance Apparatus And Method

Abstract

A trajectory guidance apparatus can guide motion with passive actuators with at least two degrees of freedom. The trajectory guidance apparatus has a linkage that is mounted to a reference and an interaction part that is to be manipulated by a master, such as a human, gravity g, water flow, a spring, or other force generator. The linkage has at least two force elements adapted to move the interaction part so that the interaction part is guided and can be moved along a prescribed path at a prescribed velocity relative to the reference. A controllable passive coupling connects the force elements and is adapted to impart passive forces against each force element of the linkage. The passive forces are derived substantially solely from a quantity of energy that is imparted to the interaction part by the master, not from other sources. A control mechanism controls the passive coupling, dynamically if desired, so that the interaction part is moved along a prescribed path of travel at a prescribed velocity by the force elements. The control mechanism essentially shifts energy from one force element to another force element during movement of the linkage so that the prescribed path and velocity are maintained.