As the demand for mobile robots that work alongside humans increases, the amount of energy that these co-robots consume will become a critical limiting factor in their deployment. This need is clearly captured in one of the fifteen main goals of the 2009 Roadmap for US Robotics which is to create a robot that can walk with half the energy consumption of a human being. At this point, the most energy-efficient walking robot is about as energy efficient as a human.
Energy efficient bipedal motion is an active area of research. It has been proven that it is theoretically possible to design a robot with intermittent support, one of the most fundamental attributes of legged locomotion, to have a zero-energy cost collisionless gait.
Optimal control has been used by a number of researchers to study the generation of periodic gaits for walking robots. However little research exists demonstrating walkers with energy efficient collisionless motion. The research that does exist demonstrates that a significant amount of the energy lost to the system when walking is from losses due to step collisions.
In this work energy efficient locomotion of a prototype actuated rimless wheel on level ground is explored using numerical optimal control. The actuated rimless wheel has an internal pendulum driven by a DC motor.
The locomotion problem is posed as an optimal control problem. Different cost functions and initial configurations are investigated and the corresponding gait trajectories analyzed and assessed based on their use of energy and the potential for collisionless motion
