Using Origami Folding Techniques to Study the Effect of Non-Linear Stiffness on the Performance of Jumping Mechanism

This research uses Origami patterns and folding techniques to generate non-linear force displacement profiles and study their effect on jumping mechanisms. In this case, the jumping mechanism is comprised of two masses connected by a Tachi-Miura Polyhedron (TMP) with non-linear stiffness characteristics under tensile and compressive loads. The strain-softening behavior exhibited by the TMP enables us to optimize the design of the structure for improved jumping performance. I derive the equations of motion of the jumping process for the given mechanism and combine them with the kinematics of the TMP structure to obtain numerical solutions for the optimum design. The results correlate to given geometric configurations for the TMP that result in the two optimum objectives: The maximum time spent in the air and maximum clearance off the ground. I then physically manufacture the design and conduct compression tests to measure the force-displacement response and confirm it with the theoretical approach based on the kinematics. Experimental data from the compression tests show a hysteresis problem where the force-displacement profile exhibits different behavior whether the structure is being compressed or released. I investigate two methods to nullify the hysteresis when compressing or releasing the mechanism and then discuss their results. This research can lead to easily manufacturable jumping robotic mechanisms with improved energy storage and jumping performance. Additionally, I learn more about how to use origami techniques to harness unique stiffness properties and apply them to a variety of scenarios.