Method of controlling the force of a pneumatic actuating device

A method for controlling an actuation force exerted by a pneumatic actuating device,

• wherein the pneumatic actuating device comprises a first working chamber and a second working chamber configured to be supplied with pressurized air by a source of pressurized air through a first pressure adjuster and a second pressure adjuster, respectively, and
• wherein said first pressure adjuster and second pressure adjuster are configured to adjust pressure of air inside the first and second working chambers, respectively, depending on a control signal,
• the method comprising iterative real-time implementation of steps of:
• a) calculating, by an optimization algorithm based on a dynamic model of the pneumatic actuating device and of said first and second pressure adjusters, desired values for control signals for said first and second pressure adjusters to generate, by the pneumatic actuating device, an actuation force equal to a desired value for the actuation force, calculation being carried out by a closed-loop proportional-integral-derivative controller based on the desired value for the actuation force, on an estimated value for the actuation force and on estimated values for pressures in said first and second working chambers and for first derivatives of said pressures, and
• b) establishing, by a state observer, the estimated value for the actuation force, the estimated values for the pressures in said first and second working chambers and for the first derivatives of said pressures, based on a measured value for the actuation force and on measured values for the pressures in said first and second working chambers.