Disclosed are Variable Displacement Power Controllers and applications generally in the field of fluid powered systems that provide for increased efficiency and effectiveness over known fluid systems, where fluid power generally refers to hydraulic or pneumatic power systems.

An actuator, such as a pressure actuator or a vacuum actuator, has a housing and a plunger that is guided through the housing. A diaphragm is connected to the housing and to the plunger and forms a gas-tight pressure chamber with the housing. A pressure medium connector is provided on the housing and communicates with the pressure chamber to pressurize the pressure chamber. A braking element is provided on the plunger and enables a braking force can be exerted on the plunger.

An actuator, such as a pressure actuator or a vacuum actuator, has a housing and a plunger that is guided through the housing. A diaphragm is connected to the housing and to the plunger and forms a gas-tight pressure chamber with the housing. A pressure medium connector is provided on the housing and communicates with the pressure chamber to pressurize the pressure chamber. A braking element is provided on the plunger and enables a braking force can be exerted on the plunger.

A lift apparatus includes a lift assembly and a servo-control system. The lift assembly includes at least one pneumatic actuator including a movable member to provide a load to transfer a substrate between a support and a transfer plane. The lift assembly further includes at least one proportional pneumatic valve to control fluid flow between the actuator and a pressurized fluid supply or a vent, a plurality of pressure sensors each to measure pressure in a respective supply line to the actuator, and at least one position sensor to measure a position of the movable member. The servo-control system includes a controller to determine an output force based on a commanded force and an estimated force, generate a control signal based on the output force, and apply the control signal to the proportional valve to move the movable member.