Bio-inspired passive variable recruitment of fluidic artificial muscles

2018 ◽  
Author(s):  
Edward Chapman ◽  
Matthew Bryant
Keyword(s):  
Artificial Muscles ◽  
Variable Recruitment

Variable recruitment in bundles of miniature pneumatic artificial muscles

2016 ◽  
Vol 11 (5) ◽  
pp. 056014 ◽  
Author(s):  
Sylvie A DeLaHunt ◽  
Thomas E Pillsbury ◽  
Norman M Wereley
Keyword(s):  
Artificial Muscles ◽  
Pneumatic Artificial Muscles ◽  
Variable Recruitment

Variable recruitment fluidic artificial muscles: modeling and experiments

2014 ◽  
Vol 23 (7) ◽  
pp. 074009 ◽  
Author(s):  
Matthew Bryant ◽  
Michael A Meller ◽  
Ephrahim Garcia
Keyword(s):  
Artificial Muscles ◽  
Modeling And Experiments ◽  
Variable Recruitment

scholarly journals Bio-inspired online variable recruitment control of fluidic artificial muscles

2016 ◽  
Vol 25 (12) ◽  
pp. 125016 ◽  
Author(s):  
Tyler E Jenkins ◽  
Edward M Chapman ◽  
Matthew Bryant
Keyword(s):  
Artificial Muscles ◽  
Variable Recruitment

Design, analysis, and validation of an orderly recruitment valve for bio-inspired fluidic artificial muscles

2021 ◽  
Author(s):  
Dheeraj Vemula ◽  
Jeong Yong Kim ◽  
Nicholas Mazzoleni ◽  
Matthew Bryant
Keyword(s):  
Tracking Error ◽  
Cross Flow ◽  
Motor Units ◽  
Recruitment Strategy ◽  
Artificial Muscles ◽  
Robot Arm ◽  
Controlled System ◽  
Variable Recruitment ◽  
And Performance ◽  
Feed Forward Controller

Abstract Biological musculature employs variable recruitment of muscle fibers from smaller to larger units as the load increases. This orderly recruitment strategy has certain physiological advantages like minimizing fatigue and providing finer motor control. Recently fluidic artificial muscles (FAM) are gaining popularity as actuators due to their increased efficiency by employing these bio-inspired recruitment strategies such as active variable recruitment (AVR). AVR systems use a multi-valve system (MVS) configuration to selectively recruit individual FAMs depending on the load. However, when using an MVS configuration, an increase in the number of motor units in a bundle corresponds to an increase in the number of valves in the system. This introduces greater complexity and weight. The objective of this paper is to propose, analyze, and demonstrate an orderly recruitment valve (ORV) concept that enables orderly recruitment of multiple FAMs in the system using a single valve. A mathematical model of an ORV-controlled FAM bundle is presented and validated by experiments performed on an ORV prototype. The modeling is extended to explore a case study of a 1-DOF robot arm system consisting of an electrohydraulic pressurization system, ORV, and a FAM-actuated rotating arm plant and its dynamics are simulated to further demonstrate the capabilities of an ORV-controlled closed-loop system. An orderly recruitment strategy was implemented through a model-based feed forward controller. To benchmark the performance of the ORV, a conventional MVS with equivalent dynamics and controller was also implemented. Trajectory tracking simulations on both the systems revealed lower tracking error for the ORV controlled system compared to the MVS controlled system due to the unique cross-flow effects present in the ORV. However, the MVS, due to its independent and multiple valve setup, proved to be more adaptable for performance. For example, modifications to the recruitment thresholds of the MVS demonstrated improvement in tracking error, albeit with a sacrifice in efficiency. In the ORV tracking performance remained insensitive to any variation in recruitment threshold. The results show that compared to the MVS, the ORV offers a simpler and more compact valving architecture at the expense of moderate losses in control flexibility and performance.

Bioinspired passive variable recruitment of fluidic artificial muscles

2018 ◽  
Vol 29 (15) ◽  
pp. 3067-3081 ◽  
Author(s):  
Edward M Chapman ◽  
Matthew Bryant
Keyword(s):  
Control Method ◽  
Applied Pressure ◽  
Artificial Muscle ◽  
High Threshold ◽  
Artificial Muscles ◽  
Control Approach ◽  
Muscle Tissues ◽  
Wide Range ◽  
Variable Recruitment ◽  
Analogous Behavior

This article presents a novel, passive approach to creating variable actuator recruitment in bundles of fluidic artificial muscles. The passive recruitment control approach is inspired by the functionality of mammalian muscle tissues, in which a single activation signal from the nervous system sequentially triggers contraction of progressively larger actuation elements until the required force is generated. Biologically, this behavior is encoded by differences in electrical resistance properties between smaller and larger muscle-fiber groups. The approach presented here produces analogous behavior using a uniform applied pressure to all fluidic artificial muscles while creating differential pressure responses and threshold pressures among the fluidic artificial muscles via tailored bladder elasticity parameters. A model for using elastic bladder stiffness to control an artificial muscle bundle with a single valve is explored and used to compare a bundle of fluidic artificial muscles with both low and high threshold pressure units to a single fluidic artificial muscle of equivalent displacement and force capability. The results of this analysis indicate the efficacy of using this control method; it is advantageous in cases where a wide range of displacements and forces are necessary and can increase efficiency when the system primarily operates in a low-force regime but requires occasional bursts of high-force capability.

Toward Variable Recruitment Fluidic Artificial Muscles

2013 ◽  
Author(s):  
Matthew Bryant ◽  
Michael A. Meller ◽  
Ephrahim Garcia
Keyword(s):  
Traditional Method ◽  
Artificial Muscle ◽  
Artificial Muscles ◽  
Experimental Characterization ◽  
Force Output ◽  
Preliminary Results ◽  
Fluidic Control ◽  
Variable Recruitment ◽  
Save Energy

We investigate taking advantage of the lightweight, compliant nature of fluidic artificial muscles to create variable recruitment actuators in the form of artificial muscle bundles. Several actuator elements at different diameter scales are packaged to act as a single actuator device. The actuator elements of the bundle can be connected to the fluidic control circuit so that different groups of actuator elements, much like individual muscle fibers, can be activated independently depending on the required force output and motion. This novel actuation concept allows us to save energy by effectively selecting the size of the actuators on the fly based on the instantaneous required load, versus the traditional method wherein actuators are sized for the maximum required load, and energy is wasted by oversized actuators most of the time. This design also allows a single bundled actuator to operate in substantially different force regimes, which could be valuable for robots that need to perform a wide variety of tasks and interact safely with humans. This paper will propose this actuator concept and show preliminary results of the design, fabrication, and experimental characterization of three such bioinspired variable recruitment actuator prototypes.

Development and Demonstration of an Orderly Recruitment Valve for Fluidic Artificial Muscles

2020 ◽  
Author(s):  
Jeong Yong Kim ◽  
Nicholas Mazzoleni ◽  
Dheeraj Vemula ◽  
Matthew Bryant
Keyword(s):  
Motor Unit ◽  
Artificial Muscle ◽  
Motor Units ◽  
Artificial Muscles ◽  
Proof Of Concept ◽  
Experimental Proof ◽  
Load Demand ◽  
Variable Recruitment ◽  
And Performance ◽  
Spool Valve

Abstract Variable recruitment fluidic artificial muscle (FAM) bundles consist of multiple FAMs arranged in motor units that are sequentially activated as load demand increases. The conventional configuration of a variable recruitment FAM bundle requires a valve for each motor unit, which is referred to as a multi-valve system (MVS). As each motor unit within the bundle is selectively recruited, this configuration is highly adaptable and flexible in performance. However, as the number of motor units increases, the valve network can become complex and heavy in its design. To decrease complexity and weight, the concept of an orderly recruitment valve (ORV) has been proposed and analyzed. The ORV allows multiple motor units to be controlled using a single valve that recruits and pressurizes all motor units. The ORV concept consists of a spool valve with multiple outlet ports and a motor unit connected to each port. A linear actuator controls the position of the spool, allowing fluid flow into each port in succession. Naturally, de-recruitment happens in reverse order. The objective of the ORV is to strike a balance between performance and compactness of design. The purpose of this paper is to present analytical modeling that can be used to understand the behavior and performance of an ORV system and develop an experimental proof-of-concept that illustrates the ORV operation in hardware. A pneumatic ORV prototype was constructed and used to actuate two FAMs sequentially, each representing a motor unit. The results demonstrate the ORV as a compact system with which a variable recruitment bundle with multiple recruitment states can be controlled.

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