Apparatus for processing an object with high position accurancy

A precision processing apparatus for processing an object (19) at accurately controlled positions, the apparatus comprising

• a working platform (12) for supporting the object (19) to be processed;
• a support structure (10) for providing support to the working platform (12), the working platform (12) being movable relative to the support structure (10) along a path, the support structure (10) containing a soft magnetic element (34) with a surface that extends in parallel with said path;
• an suspension actuator part (14) attached to the working platform (12), the suspension actuator part (14) comprising a soft magnetic core (24) with poles facing the surface of the soft magnetic element (34) and a winding (20) for application of a current to generate a magnetic field that runs through the core (24) via the poles and returns via the soft magnetic element (34);
• a position reference element (16), mechanically decoupled from the soft magnetic element (34);
• a sensor (17) for producing a sensing result indicative of a measured position of the suspension actuator part (14) relative to the position reference element (16);
• a control circuit comprising an outer control circuit (40) and an inner control circuit (42), the outer control circuit (40) receiving said sensing result and determining force set point information to regulate the measured position of the actuator part (14) to a required value, the inner control circuit (42) receiving the force set point information and controlling the current to realize a force between the actuator part (14) and the support structure (10) according to the force set point information.