Morphological computation: A basis for the analysis of morphology and control requirements

The fact that the morphology of a robot affects its control requirements has become increasingly evident in robotics. Not only does the morphology determine the behaviors that can be performed, but also the amount of control required for these behaviors. Particularly in systems where behavior is obtained through purely sensory-motor interactions of the body with the environment, the morphology is of prime importance. Nonetheless, even in other robotic systems, a relationship has been found to exist between morphology and control requirements, in that some morphologies yield themselves to being more easily controlled than others. This relationship was first observed and characterized by Pfeifer as the morphology and control trade-off [R. Pfeifer, C. Scheier, Understanding Intelligence, MIT Press, Cambridge, MA, 1999], but the mechanisms underlying this relationship have been unclear. However, the discovery of morphological computation,1 [C. Paul, Investigation of Morphology and Control in Biped Locomotion, Ph.D. Thesis, Department of Computer Science, University of Zurich, Switzerland, 2004], the phenomenon that computation can be obtained through interactions of physical form, elucidates a possible mechanism underlying this relationship. The fact that simple physical interactions give rise to computation indicates the theoretical possibility for the dynamics of the morphology to play a computational role in the system, and thereby to subsume part of the role of control. Thus, it may serve to analyse the relationship between morphology and control, and guide the design of robots with reduced control requirements. The goal of the paper is to explore this possibility. The paper introduces the concept of morphological computation in the context of robot morphology, discusses its potential role in the morphology and control trade-off, and then uses it as a basis to develop a heuristic for the design of robots with reduced control requirements. The heuristic is then tested through experiments to validate its accuracy. The preliminary results are promising, and suggest that morphological computation can be a suitable framework for the analysis of morphology and control requirements. c © 2006 Elsevier B.V. All rights reserved.