Hydraulic control system

Abstract From the Canadian patent

An articulated arm employs a controller to generate .delta.r .delta..THETA. and .delta.z, signals for controlling the movement of the arm in r .THETA. and z directions , to, produce movement of an end point from an initial location along a desired path toward a desired location. The actual location is determined by sensing the relationships between the arm segments and determining the actual location of the end point. The actual location is continuously compared with the desired location represented by the r, a and z signals and if the difference between , the, actual location and desired location exceeds preselected limits the .delta.r, .delta..THETA. and, .delta.z are scaled down thereby …