Compliant constant-force mechanism with a variable output for micro/macro applications

The relationship between input deflection and output force is fixed for constant-force mechanisms. An advantage of a constant-force mechanism is that the control effort is minimized. For example, in grasping applications, if the grasp force is understood and given, then the mechanism will apply the constant-force even if there are small deflections. A double-slider, variable, constant-force mechanism is developed in this paper. The force relationship is analyzed using the virtual network principle. An active control law is used to generate a variable constant-force output. The paper also discusses the experimental validation of the force relationship using springs and also compliant plastic materials. This macro-level research is a step towards developing the technical capability to design micro constant-force mechanisms.