Patent ID: 7076314

Claim:
A precision positioning device comprising: a pneumatic cylinder fixed so as to extend along the vertical direction; a piston member slidably accommodated in the pneumatic cylinder in a non-contact state via bearings, and including a piston head and a rod extending from the piston head along the central axis direction, the inside of the pneumatic cylinder being divided into two pressure chambers by the piston head; a pneumatic circuit for supplying a gas at a constant pressure to one of the two pressure chambers and supplying the gas at a controlled flow rate to the other of the pressure chambers via a servo valve; first and second pressure sensors for detecting pressures of the one and the other of the pressure chambers, respectively; a position sensor for detecting the position of the piston member; and a control system, wherein the control system performs position control with respect to the piston member by controlling the servo valve based on a position detection signal from the position sensor, a position command value, a velocity command value, and an acceleration command value; wherein the control system performs force control with respect to the piston member by controlling the servo valve using pressure detection signals from each of the first and second pressure sensors and a load command value; wherein the bearings are each a first hydrostatic bearing, wherein the piston member has an aperture formed in the central axis portion thereof and extending along the central axis direction thereof, and wherein the position sensor is formed in the piston member through the use of a fixed shaft that has been inserted into the aperture from above the pneumatic cylinder.