Control of a pneumatic gantry robot for grinding: performance with conventional techniques

The ability of a pneumatic gantry robot to grind the edges of steel blanks was evaluated experimentally. It was found that surface quality improved after edge grinding with the applied force regulated to 30 N. Three different pneumatic circuit and force control system configurations were examined. A variance of plusmn5 N was obtained with a PLC-based open loop controller that used on/off directional valves and a manually adjusted pressure regulator. The variance was reduced to plusmn1.5 N with a PC-based closed loop PID controller that used proportional pressure valves. This level of performance with conventional industry control techniques was considered acceptable for the application at hand. However, the results are presented as a performance benchmark for measuring the value of more advanced control techniques in future studies