<title>Whole-body task energy metrics for robots performing useful work in unstructured environments</title>

Abstract

When considering energy requirements and optimization for robots, it is important to consider mission requirements, and the type of robot performing the mission. For example, the small robots used in today's reconnaissance and explosive ordnance disposal applications have weak manipulators, and do not perform significant physical work on their surrounding environment. In this paper, we focus on robots that will be required to do much more physically demanding tasks, such as manipulating large heavy objects in unstructured environments, and carrying such objects over challenging terrain. Energy considerations for such systems must include models of physical work performed for basic manipulation, pose transition, and locomotion maneuvers. Given the scarcity of robots that can perform useful work in unstructured environments, it is useful to begin the investigation of energy optimization for such robots by considering typical tasks they might perform. This paper makes three contributions in this direction. First, we develop a set of standard tasks that would be useful in unstructured environments. The tasks are expressed in terms of the objects being manipulated, and the work being done, so they are independent of robot morphology. Second, we develop energy metrics and analytical results for theoretical energy requirements for these tasks. These requirements assume no losses due to friction, so they give a best-case estimate of what is achievable. Such metrics are useful in subsequent evaluation of real systems that are not as efficient. Third, we perform preliminary comparisons between different actuation technologies in performing these tasks. These actuation technologies will include electro-mechanical and hydraulic systems. We compare these technologies in terms of power density, and evaluate expected energy efficiency when performing the metric tasks.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.