2015 article

Modeling of the energy savings of variable recruitment McKibben muscle bundles

BIOINSPIRATION, BIOMIMETICS, AND BIOREPLICATION 2015, Vol. 9429.

By: M. Meller*, J. Chipka*, M. Bryant n & E. Garcia *

co-author countries: United States of America πŸ‡ΊπŸ‡Έ
author keywords: McKibben muscle; energetics; efficiency; variable recruitment; fluid power; hydraulic control systems
Source: Web Of Science
Added: August 6, 2018

McKibben artificial muscles are often utilized in mobile robotic applications that require compliant and light weight actuation capable of producing large forces. In order to increase the endurance of these mobile robotic platforms, actuation efficiency must be addressed. Since pneumatic systems are rarely more than 30% efficient due to the compressibility of the working fluid, the McKibben muscles are hydraulically powered. Additionally, these McKibben artificial muscles utilize an inelastic bladder to reduce the energy losses associated with elastic energy storage in the usual rubber tube bladders. The largest energy losses in traditional valve-controlled hydraulic systems are found in the valving implementation to match the required loads. This is performed by throttling, which results in large pressure drops over the control valves and significant fluid power being wasted as heat. This paper discusses how these throttling losses are reduced by grouping multiple artificial muscles to form a muscle bundle where, like in skeletal muscle, more elements that make up the muscle bundle are recruited to match the load. This greatly lessens the pressure drops by effectively changing the actuator area, leading to much higher efficiencies over a broader operation envelope. Simulations of several different loading scenarios are discussed that reveal the benefits of such an actuation scheme.