1. A method for controlling the motion of a mechanism in an artificial appendage or a humanoid robot, said mechanism consisting of multiple articulated elements connected at one or more joints, said method comprising, in combination, the steps of: providing a controller for processing current state input data indicating the current dynamic state of said mechanism and desired state input data indicating the desired dynamic state of said mechanism to produce output element acceleration data indicating the amount by which said elements should be accelerated so that said current dynamc state is altered to more nearly conform to said desired dynamic state, employing a stored linear relationship between the element and joint accelerations of said mechanism to convert said output element acceleration data into computed joint acceleration data indicating the amount by which the movement of said elements about each of said joints should be accelerated, employing a stored linear relationship between joint accelerations and joint torques to compute joint torques that achieve desired joint accelerations. and