Precision servo control system for a pneumatic actuator

An automated method of controlling a pneumatic actuator operably connected to a piston in a chamber and to a brake wherein a sensor system generates measurement values representative of a movement of the piston, the method comprising:

• supplying a pressurized gas to a forward side of the piston to accelerate the piston along a stroke;
• and
• beginning at a deceleration point along the stroke that is determined at least in part in response to the measurement values generated by the sensor system,
• supplying the pressurized gas to a reverse side of the piston while continuing to supply the pressurized gas to the forward side of the piston;
• and
• selectively activating the brake in response to the measurement values generated by the sensor system to stop the pneumatic actuator within a predetermined tolerance of a desired stopping position,
• wherein after at a predetermined condition after the deceleration point is determined at least in part in response to the measurement values generated by the sensor system the pressurized gas is discontinued to the reverse side of the piston but is continued to be supplied to the forward side of the piston;
• and
• wherein the predetermined condition is the first of a defined percentage of a distance from the deceleration point to the desired stopping position and a defined percentage reduction in a velocity of the piston.

A precision servo control system for a pneumatic actuator comprising:

• a pneumatic actuator having a positionable component with a stroke length;
• a supply of pressurized gas operably connected to provide a forward thrust and a reverse thrust to said positionable component;
• a brake operably connected to said actuator;
• a sensor system that determines a measurement of said positionable component along said stroke length;
• and a servo control system electrically connected to said supply, said brake, said sensor system and said pneumatic actuator, wherein said control system operates to initiate the forward thrust to move the positionable component along said stroke length and once a deceleration point along said stroke length is reached initiates the reverse thrust while maintaining the forward thrust and simultaneously selectively applies the brake to stop the positionable component within a predetermined tolerance of a desired stopping position.

A precision servo control system for a pneumatic actuator comprising:

• a pneumatic actuator having a positionable component with a stroke length;
• a supply of pressurized gas operably connected to provide a forward thrust and a reverse thrust to said positionable component;
• a brake operably connected to said actuator;
• a sensor system that determines a measurement of said positionable component along said stroke length;
• and a servo control system electrically connected to said supply, said brake, said sensor system and said pneumatic actuator, wherein said control system operates to initiate the forward thrust to move the positionable component along said stroke length and once a deceleration point along said stroke length is reached initiates the reverse thrust while maintaining the forward thrust and simultaneously selectively applies the brake to stop the positionable component within a predetermined tolerance of a desired stopping position,
• wherein the brake is a proportional brake.

A pneumatic-actuator system comprising:

• an actuator having a pneumatically-positionable component;
• and
• a control system having at least one tunable gain parameter,
• wherein said control system moves said component from a first position to a second position while said component carries a first load while maintaining a predetermined position tolerance without a change in any of said at least one tunable gain parameters, and
• wherein said control system moves said component from said second position to a third position carrying a second load, said second load at least 33% different from said first load while maintaining said predetermined position tolerance without a change in any of said at least one tunable gain parameters.

An automated method of controlling a pneumatic actuator operably connected to a piston in a chamber and to a brake wherein a sensor system generates measurement values representative of a movement of the piston, the method comprising:

• supplying a pressurized gas to a forward side of the piston to accelerate the piston along a stroke;
• beginning at a deceleration point along the stroke that is determined at least in part in response to the measurement values generated by the sensor system, selectively activating the brake in response to the measurement values generated by the sensor system to stop the pneumatic actuator within a predetermined tolerance of a desired stopping position;
• and
• in the event of an overshoot where the piston advances beyond the desired stopping position by more than the predetermined tolerance,
• discontinuing supplying the pressurized gas to the forward side of the piston;
• fully activating the brake to hold the piston in position;
• supplying a pressurized gas to a backward side of the piston;
• and
• selectively partially releasing the brake to allow the piston to move back along the stroke to the desired stopping position.

An automated method of controlling a pneumatic actuator operably connected to a piston in a chamber and to a brake wherein a sensor system generates measurement values representative of a movement of the piston, the method comprising:

• supplying a pressurized gas to one side of the piston to accelerate the piston along a stroke;
• selectively activating the brake to maintain a velocity of the piston below a predetermined homing speed;
• monitoring the measurement values of the sensor system to determine when the piston has stopped moving along the stroke;
• setting a reference value of the sensor system to zero to represent a home position based on the measurement values for a current position of the piston when it has stopped.