Beltsville, MD, United States
Beltsville, MD, United States

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Woods B.K.S.,University of Swansea | Kothera C.S.,InnoVital Systems, Inc. | Wang G.,University of Alabama in Huntsville | Wereley N.M.,University of Maryland University College
Smart Materials and Structures | Year: 2014

This study presents a time domain dynamic model of an antagonistic pneumatic artificial muscle (PAM) driven trailing edge flap (TEF) system for next generation active helicopter rotors. Active rotor concepts are currently being widely researched in the rotorcraft community as a means to provide a significant leap forward in performance through primary aircraft control, vibration mitigation and noise reduction. Recent work has shown PAMs to be a promising candidate for active rotor actuation due to their combination of high force, large stroke, light weight, and suitable bandwidth. When arranged into biologically inspired agonist/antagonist muscle pairs they can produce bidirectional torques for effectively driving a TEF. However, there are no analytical dynamic models in the literature that can accurately capture the behavior of such systems across the broad range of frequencies required for this demanding application. This work combines mechanical, pneumatic, and aerodynamic component models into a global flap system model developed for the Bell 407 rotor system. This model can accurately predict pressure, force, and flap angle response to pneumatic control valve inputs over a range of operating frequencies from 7 to 35 Hz (1/rev to 5/rev for the Bell 407) and operating pressures from 30 to 90 psi. © 2014 IOP Publishing Ltd.


Robinson R.M.,University of Maryland University College | Kothera C.S.,InnoVital Systems, Inc. | Wereley N.M.,University of Maryland University College
IEEE/ASME Transactions on Mechatronics | Year: 2015

This paper investigates the orderly recruitment of pneumatic artificial muscles for efficient torque production in a robotic manipulator. Pneumatic artificial muscles (PAMs) are arranged in a parallel bundle, and independently-controlled 'motor units' are employed to imitate the structure and function of human skeletal muscle. Simulated cycling tests are conducted on a model of the robotic manipulator to quantify the benefits of variable recruitment, and experimental testing is performed to validate the simulated predictions. Results reveal a distinct relationship between recruitment and system efficiency. Key factors influencing the value of a variable recruitment strategy include nonlinear PAM bladder elasticity, pneumatic losses, and dissipative forces in the robotic joint. Recruitment guidelines are proposed to maximize efficiency over a range of payload masses. The potential challenges associated with maintaining smooth motion control during discrete transitions in recruitment are also identified and discussed. © 1996-2012 IEEE.


Robinson R.M.,U.S. Army | Kothera C.S.,InnoVital Systems, Inc. | Sanner R.M.,University of Maryland University College | Wereley N.M.,University of Maryland University College
IEEE/ASME Transactions on Mechatronics | Year: 2016

Lightweight, compliant actuators are particularly desirable in safety-conscious robotic systems intended for interaction with humans. Pneumatic artificial muscles (PAMs) exhibit these characteristics and are capable of higher specific work than comparably sized hydraulic actuators and electric motors. However, control of PAM-actuated systems has proven difficult due to the highly nonlinear nature of the actuators and the pneumatic systems driving their actuation. This study develops and investigates the performance of three advanced control strategies - sliding mode control, adaptive sliding mode control, and adaptive neural network (ANN) control - each containing a distinct level of a priori model knowledge, to enable smooth and accurate motion tracking of a single degree-of-freedom PAM-actuated manipulator. Originally developed by J.-J. Slotine and R.M. Sanner, the specific controllers employed in this study are significantly modified for application to pneumatically actuated open-chain manipulators with complex nonlinear dynamics. The two adaptive controllers are updated online and require no pretraining step. Several experiments are performed with each controller to evaluate and compare closed-loop tracking performance. Results highlight the dependence of a preferred control strategy on the level of model completeness and quality, and suggest that in most PAM-actuated manipulator scenarios, the ANN controller is preferable because it does not require a model of the pneumatic system or joint mechanism design, which can be difficult and time consuming to characterize, and is robust to changes in PAM actuator characteristics (due to fatigue or replacement). © 1996-2012 IEEE.


Woods B.K.S.,University of Maryland University College | Kothera C.S.,InnoVital Systems, Inc. | Wereley N.M.,University of Maryland University College
Journal of the American Helicopter Society | Year: 2014

A novel active trailing edge flap system nominally sized for a 35-ft (10.7-m)-diameter four-bladed rotor was developed and whirl tested. The pneumatic artificial muscle actuators employed have several attractive properties, including large forces and displacements, excellent specific work, and robustness. Two pneumatic artificial muscles weremounted antagonistically in the blade root and were connected to an outboard trailing edge flap via bell cranks and linkages. The system was sized to produce flap deflections at frequencies up to 5/rev (N+1/rev) for vibration reduction, as well as large 1/rev deflections for primary rotor control. A quasistatic model of system performance was developed and used to determine the best available actuator geometry and to optimize the kinematics of the linkage system. A subspan, vacuum chamber whirl test rig was developed for testing under full-scale centrifugal, inertial and simulated aerodynamic loading. The performance of the system under a range of operating conditions was evaluated. Large output flap deflections under full-scale loading show the promise of this actuation system. © 2014 The American Helicopter Society.


Robinson R.M.,University of Maryland University College | Kothera C.S.,InnoVital Systems, Inc. | Wereley N.M.,University of Maryland University College
Journal of Intelligent Material Systems and Structures | Year: 2015

Pneumatic artificial muscles are actuators known for their low weight, high specific force, and natural compliance. Employed in antagonistic schemes, these actuators closely mimic biological muscle pairs, resulting in applications for humanoid and other bio-inspired robotic systems. Such systems require precise actuator modeling and control in order to achieve high performance. In the present study, refinements are introduced to an existing model of pneumatic artificial muscle force-contraction behavior. The force-balance modeling approach is modified to include the effects of non-constant bladder thickness and up to a fourth-order polynomial stress-strain relationship is adopted in order to accurately capture nonlinear pneumatic artificial muscle force behavior in contraction and extension. Moreover, the polynomial coefficients of the stress-strain relationship are constrained to vary linearly with pressure, improving the ability to predict behavior at untested pressure levels while preserving model accuracy at tested pressure levels. Lastly, a detailed geometric model is applied to improve force predictions, particularly during pneumatic artificial muscle extension. By modeling the deformation shape of the actuator ends as sections of an elliptic toroid, pneumatic artificial muscle force predictions as a function of strain are improved. These modeling improvements combine to enable enhanced model-based control in pneumatic artificial muscle actuator applications. © The Author(s) 2014.


Grant
Agency: Department of Defense | Branch: Defense Health Program | Program: SBIR | Phase: Phase II | Award Amount: 999.94K | Year: 2015

Many emergency cricothyrotomy kits have been developed in an attempt to simplify this potentially life-saving medical procedure. However, none of the existing kits perform noticeably better than the standard surgical kit. The standard kit itself has led


Grant
Agency: Department of Defense | Branch: Army | Program: SBIR | Phase: Phase II | Award Amount: 499.79K | Year: 2015

Following a successful and promising Phase I effort, InnoVital Systems, (formerly Techno-Sciences, Inc.), in collaboration with ILC Dover, proposes to continue development of the novel AirFloor system - a light weight, low cost, air encapsulated structural flooring system to attenuate the loads transmitted to the occupant during a blast event. The proposed AirFloor technology builds upon the teams expertise in developing passive and adaptive energy mitigating technologies and engineered inflatables.


Grant
Agency: Department of Defense | Branch: Defense Health Program | Program: SBIR | Phase: Phase I | Award Amount: 149.99K | Year: 2014

Many emergency cricothyrotomy kits have been developed in an attempt to simplify this potentially life-saving medical procedure. However, none of the existing kits perform noticeably better than the standard surgical kit. The standard kit itself has led to a reported failure rate of 33% when performed in combat environments, and airway obstruction is reported to be the third most preventable cause of death on the battlefield. The high failure rate is at least partially attributable to inadequate training and experience. As such, InnoVital Systems, Inc. proposes to develop an innovative universal device that is light weight, packable, and adjustable to different size soldiers or patients that will significantly increase ease of use and efficacy of performing cricothyrotomies. Building upon our experience in medical device design, evaluation, and clearance, we will perform design, analysis, fabrication, and FDA clearance planning in Phase I of the project, which will end with prototype bench tests. Phase II will focus on further design refinements and functional hardware validation of the final design with selected materials, and executing the steps necessary for FDA device clearance.


Grant
Agency: National Aeronautics and Space Administration | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 125.00K | Year: 2014

Dexterous performance degradation resulting from donning an extra-vehicular activity (EVA) glove limits the capability of astronauts to perform certain tasks in space. This measurable performance loss has led to a number of design revisions, but barehanded performance with an EVA glove on is still far from achievable. Exoskeleton concepts have also been considered to add some of the lost dexterous capability, but technology and design challenges have limited their practical utility. As such, InnoVital Systems, Inc., in collaboration with the Space Systems Laboratory of the Aerospace Engineering Department at the University of Maryland, proposes to develop an innovative EVA glove exoskeleton for increased performance capability. The proposed concept will employ the team's novel, miniature pneumatic artificial muscles to drive the multiple degrees of freedom of the hand to restore the functionality lost by wearing the EVA glove. Building upon our experience in actuation, control, and space suit systems, as well as biomimetic applications, we will perform design, analysis, and fabrication in Phase I of the project, which will end with preliminary prototype testing and feasibility demonstrations. Phase II will focus on further design refinements, controls system development, and full-scale prototype development and testing.


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