This paper discusses three main problems associated with the control of the motion of a mechanical arm. 1) Transformation between different coordinate systems associated with the arm. 2) Calculation of detailed trajectories for the arm to follow. 3) Calculation of the forces which must be applied to the joints of the arm in order to make it move along a specified path. Each of the above problems is amenable to exact solution. However, the resulting equations are, in general, quite complex and difficult to compute. This paper investigates several methods for speeding up this calculation, and for getting approximate solutions to the equations.
