Design and analysis of bi-stable grasper mechanisms highly parallel to the ground

In combination with the rigid-body replacement synthesis design approach, a double parallelogram lifting platform based on a lamina emergent mechanism is designed, which overcomes the disadvantage of a single parallelogram mechanism and improves the parallelism. Then a bi-stable grasper is designed, which is limited the slider movement to control the clamping force, using the second balanced state as a working condition to maintain a constant clamping force. At last these two parts are combined by subsidiary in order to drive the lift and clamp movement by only one motion. At the same time, based on a pseudo-rigid-body model, the force-displacement relationship is derived. One practical example is calculated according to this theory and is analyzed by finite element simulation to verify the correctness of the theory and the usability of the mechanism.