Trialing Springy Foot Designs for a Novel Hopping Mechanism
In this project, we show our preliminary results on trials of different spring foot designs for a hopping mechanism. We are motivated by the fact that High impact hopping can lead to small airborne phases that deteriorate energetic performance. We found that springy foot designs with circular shapes and different materials would eliminate the small airborne phases and therefore improve the hopping performance. Check out the presentation I gave at the 2022 Dynamic Walking conference here, as well as the hardware demo!
Experimental Validation of The Usage of Kinematic Singularities to Produce Periodic High-Powered Motion
In this project, preliminary experiments of recently proposed mechanism kinematics for a legged robot are conducted. The proposed kinematics creates a mapping from a series-elastic actuator to a foot motion that includes a pair of singularities within a fully rotatable kinematic circuit. Such a circuit is less common and only possible with certain multi-loop linkages. A slice of the configuration space displaying series-elastic rotation versus linear foot motion presents a characteristic S shape, motivating the name S-curve kinematics. Our experimental results show that S-curve kinematics can enhance the energetic output of a series-elastic actuator in a hopping task versus the usage of a conventional rotary-to-linear mechanism. This is possible because S-curve kinematics enable elastic energy storage outside of stance that is released through a mechanical reflex. Compared to a conventional rotary-to-linear actuator, S-curve kinematics demonstrated up to a 4x increase in kinetic output.
4-minute accompanying video:
The Usage of Kinematic Singularities to Produce Periodic High-Powered Locomotion
In this project, we seek to provide a particular mechanical reflex paradigm which, by systematically integrating kinematic singularities into the leg design, gives stable and efficient periodic motions of a hopping robotic system that exhibit highly agile dynamic behaviors. Check out the videos below!
1-minute spotlight video:
15-minute presentation:
Evaluating Plane Curves as Constraints for Locomotion on Uneven Terrain
This project focuses on preliminary work related to the discovery of single degree-of-freedom mechanism paths useful for dynamic locomotion tasks. The objective is to bridge a gap between kinematic specifications and emerging dynamic behaviors. This is accomplished by formulating a set of ordinary differential equations that includes essential mechanism characteristics (path traced, mechanical advantage) but excludes all physical mechanism parameters (topology, link lengths). The dynamics represent a rotation constrained body propelled by a foot that is attached to that body by a user-defined path. The foot is powered by a series-elastic actuator acting through a mechanical advantage function that is defined across the length of the path. Through this framework, a range of user-defined paths were tested for effective locomotion on flat and complex terrains. Footpaths and mechanical advantage functions exist outside of any mechanical design, with the goal to discover paradigms worth instantiating into physical mechanisms, a task reserved for kinematic synthesis. This work would empower existing kinematic synthesis techniques to achieve dynamic requirements. Check out the videos below!
8-minute presentation:
Curves demonstrations:
More coming up soon!