Abstract: A multi-mode force control apparatus and circuit for applying a predetermined time dependent force to a workpiece having a variable compliance. The workpiece is supported by an anvil and an actuator is used for applying force to the workpiece. The multi-mode force control apparatus has a position mode sequence that provides a composite position command signal characterizing the predetermined time dependent position of the hammer. A position servo amplifier provides an input control signal to move the hammer from a retracted position to a predetermined first position close to the workpiece. The hammer is then moved slowly into contact with the workpiece. A force reference command signal representing the predetermined time dependent force is increased to a predetermined value. A force signal from a force transducer then rises to a value of voltage representing an ultimate actual force value. A force hold mode timing sequence provides a force hold mode time interval.