Optimal control of a half-circular compliant legged monopod

AYDIN Y. O., SARANLI A., YAZICIOĞLU Y., SARANLI U., LEBLEBICIOGLU K.

CONTROL ENGINEERING PRACTICE, vol.33, pp.10-21, 2014 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 33
  • Publication Date: 2014
  • Doi Number: 10.1016/j.conengprac.2014.08.005
  • Journal Name: CONTROL ENGINEERING PRACTICE
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.10-21
  • Keywords: Optimal control, Legged robots, Compliant leg, Monopod, RHex, TAKE-OFF TECHNIQUES, WALKING, DESIGN, MODEL, LOCOMOTION, DYNAMICS, FOOT, RHEX
  • Middle East Technical University Affiliated: Yes

Abstract

This paper investigates an optimal control strategy for the dynamic locomotion of a simplified planar compliant half-circular legged monopod model. We first present a novel planar leg model which incorporates rolling kinematics and a new compliance model, motivated by the use of similar leg designs on existing platforms. Two locomotion tasks, moving at a prescribed horizontal velocity and a one-shot jump to maximum possible height or length, are then investigated within this model. The designs of two high-level optimal controllers for these tasks are then described to investigate the performance and stability of resulting behaviors, based on the optimization of trajectory parameters for a closed-loop low-level Proportional-Derivative controller at the hip. Our results show that with these optimized parameters the robot can achieve stable locomotion at a desired horizontal velocity and can successfully jump over and across a specified height and length. Finally, the composition of objective functions capturing multiple criteria is also investigated for the one-shot jump task. (C) 2014 Elsevier Ltd. All rights reserved.