Machinery Positioning Apparatus Having Independent Drive Columns

A controller for a positioning apparatus, the controller comprising:

• a processor;
• an input module associated with said processor for receiving a control input indicative of a position for the positioning apparatus;
• a sensor module associated with said processor for receiving a plurality of sensor signals from each of a plurality of positioning columns, the plurality of columns each having a first support and a motor for moving the first support along an axis of the column;
• a position module associated with said processor for calculating a position of each of the first supports from at least a first one of the sensor signals;
• a load module associated with said processor for calculating a load on each of the columns from at least a second one of the sensor signals;
• a control signal module associated with said processor for comparing the positions of each first support, the loads on each of the columns and the control input to generate a control signal;
• wherein the controller transmits the control signal to at least one of the motors to control the position of at least one of the first supports.