The design of a PKM-type composite actuator for servo mechanical presses

Servo mechanical presses are widely applied in manufacturing. However, due to the limitation of strength of the ball screw and power of servomotor, the single degree of freedom (DOF) linkage mechanism driven by a servomotor is not suitable for the mechanical presses with a heavy duty capacity. For this reason, we propose a so-called parallel redundant actuation scheme for providing servo mechanical presses with large driving force. In addition, a dual screw transmission mechanism with two DOF is also presented. Comparing with the single screw transmission mechanism, the dual screw transmission mechanism is more powerful (driven by two servo motors), more reliable and feasible (2 DOF parallel mechanism permits differences between inputs), more safety (Even though one servomotor is failed, the other one may run the mechanism on the rails) and more spaces saving (without supporting guide way). Based on parallel mechanism and dual screw transmission mechanism, a PKM-type composite actuator can be constructed for servo mechanical presses.