Design, Control and Optimization of Robotic Systems with Energy Regeneration

Cleveland State University, Cleveland OH

Investigators

Abstract

Many industrial, consumer and medical products involve masses in motion. These motions are powered from energy sources, and always involve cycles of acceleration and deceleration. Conventional braking is a very inefficient method of deceleration because the object's energy is wasted as heat. In contrast, regeneration involves surplus energy capture and storage into the power supply. Regeneration engineering is advanced and visible in electric and hybrid vehicles, but its understanding and optimal utilization in mobile and industrial robotics remains a challenging area of research. The outcomes of this research have the potential for significant energy savings in industrial installations where many robots are in use. Mobile biomedical devices powered from electric energy sources such as wheelchairs, prostheses and exoskeletons are another target application of this research. Optimal energy utilization in these devices will translate into lighter units with a reduced need for frequent recharging. Impaired people wearing advanced regenerative prostheses will be able to extend the range of their daily activities, improving their quality of life. This research will introduce a systematic treatment of general motion control problems with explicit consideration of bidirectional energy flow. The intellectual significance of the project is centered in its generality and broad applicability, which contrasts with the mostly case-oriented current literature on regenerative systems. The project focuses on the use of ultracapacitors as key elements of advanced regenerative systems. In comparison to batteries, ultracapacitors have very high power densities. This means that energy extraction and return can be achieved at fast rates. This feature affords great flexibility to alter a robot's dynamic behavior by means of control, in particular its mechanical impedance. Moreover, recent advances in graphene-based ultracapacitors have resulted in devices with energy densities approaching those of lithium-ion batteries. These advances have the potential for the elimination of batteries in certain mobile robotic systems, particularly in medical assistive devices. The project will establish a framework to design, control and optimize such systems. The project has three goals: 1. development of new approaches for modeling, control and design of robotic systems with advanced regenerative hardware such as ultracapacitors; 2. formulation and solution of fundamental energy-motion multi-objective optimization problems for the same; 3. bridging of theory and practice with a custom-built study robot.