Design, development and modelling of single actuated, compliant and symmetrical multi link hopping mechanism

In this study, we present the design and development of a compliant multi-link hopping mechanism actuated by a single DC motor. Mechanism consists of torsional spring, two symmetrically arranged six bar mechanism connected through the bottom gears and a compliant preloaded pinned-pinned buckling beam serving as a nonlinear spring. Kinematic and dynamical analysis are performed using both Newtonian dynamics, vector closure loop equations and geometric constrains of the design to predict the motion of the mechanism. Adams simulations are performed to obtain the force-deflection curve for flexible beam and torque-angular displacement curve for flat spiral spring. Mechanism is built by 3D printing all parts using thermoplastic based polylactic acid PLA filament. Continuous hopping motion is created without requirement of any hydraulic and pneumatic actuators or mechanical springs to store and release energy during the complete motion. The actuator is connected to a 3D printed flat spiral spring to control the speed and pinned-pinned buckling beam is attached in between two symmetrical multi-link mechanism to increase the effect of impact.