Controlling a bipedal walking robot actuated by pleated pneumatic artificial muscles

Abstract

This paper reports on the control structure of the pneumatic biped Lucy. The robot is actuated with pleated pneumatic artificial muscles, which have interesting characteristics that can be exploited for legged locomotion. They have a high power to weight ratio, an adaptable compliance and they can absorb impact effects.The discussion of the control architecture focuses on the joint trajectory generator and the joint trajectory tracking controller. The trajectory generator calculates trajectories represented by polynomials based on objective locomotion parameters, which are average forward speed, step length, step height and intermediate foot lift. The joint trajectory tracking controller is divided in three parts: a computed torque module, a delta-p unit and a bang-bang pressure controller. The control design is formulated for the single support and double support phase, where specifically the trajectory generator and the computed torque differs for these two phases.The first results of the incorporation of this control architecture in the real biped Lucy are given. Several essential graphs, such as pressure courses, are discussed and the effectiveness of the proposed algorithm is shown by the small deviations between desired and actual attained objective locomotion parameters.

Segmented Foot with Compliant Actuators and Its Applications to Lower-Limb Prostheses and Exoskeletons

“…However, mechanically compliant systems, such as elastic joints, may be used for shock absorbtion and be exploited to store energy and decrease control complexity. As a new trend in robotics, various kinds of compliant actuators and compliant joints have been introduced to real robot applications, for instance, hexapod robot [28], quadruped system [29] and bipedal walking [30].…”

“…The well-known artificial muscles in the field of dynamic walking are the pneumatic McKibben muscles [37]. In addition, the Pleated Pneumatic Artificial Muscle (PPAM) designed by [38], has been successfully implemented in the biped Lucy [30]. However, such air muscles based mechanisms may be the barrier that constrains the dynamic walking systems, especially the lower-limb prostheses and exoskeletons, in practical use.…”

Development of a compliance controller to reduce energy consumption for bipedal robots

“…The control architecture is similar to that used for the biped Lucy (see Vanderborght et al 2006a) and is depicted in Fig. 6.…”

Model-Based Evolution of a Fast Hybrid Fuzzy Adaptive Controller for a Pneumatic Muscle Actuator

“…Nevertheless, a lot of effort has gone into PAM-based systems research corroborated by a number of various works, for example see [1][2][3][4][5]. There are basically two main areas for which various PAM applications have been proposed: robotics [6][7][8][9] and biomedical engineering [10][11][12]. Each of these areas has its specific requirements causing the selected approaches for a PAM-based system design to differ slightly.…”