Analysis and design of a constant force gripper

Constant force mechanisms have significant advantages over conventional force control methods, especially in terms of cost and design complexity. In this thesis a novel constant force gripper mechanism is introduced. This mechanism has great potential for constant force gripping applications. The mechanism is driven with constant input torque that can easily be supplied from a DC motor, since constant current yields constant torque output for a DC motor. Thus, sensors and controller can be eliminated from the system. Constant force is achieved via several links and springs. Numerous mechanical solutions for torque transmission and creation of equivalent systems by shifting spring positions are presented. By means of dimensionless parameters approach, parametric solutions and scalable applications are obtained to achieve constant force throughout large strokes. Finally, a prototype is built and theoretical approaches are verified with experimental results.