Mechanical design and evaluation of an actuator and a simulator for trans-tibial and trans-femoral prostheses

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/09544062211036915 ◽

2021 ◽

pp. 095440622110369

Author(s):

Akin Oguz Kapti ◽

Ahmet Karaca

Keyword(s):

Mechanical Design ◽

Air Pressure ◽

Experimental Results ◽

Position Tracking ◽

Good Position ◽

Series Elastic Actuator ◽

Orthopedic Disabilities ◽

Assistive Systems ◽

Series Elastic

This study proposes a joint simulator to evaluate new prosthesis designs prior to patient trials to minimize the inconveniences encountered in prosthesis applications for amputees. Design and prototype manufacturing of a force-controlled series elastic actuator was realized. In addition, actively controlled trans-tibial and trans-femoral amputation prostheses were designed by utilizing this actuator. A pneumatic joint simulator consisting of a proportional air pressure valve was also designed and manufactured. The experimental results demonstrated that good position tracking performances and effective assistive forces under the simulated walking conditions were achieved. The developed systems have the potential to contribute to the improvement of inadequate features of passive prostheses and to the development of new assistive systems that better respond to the needs of people with orthopedic disabilities.

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A Novel Variable Impedance Compact Compliant Series Elastic Actuator: Analysis of Design, Dynamics, Materials and Manufacturing

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.245.99 ◽

2012 ◽

Vol 245 ◽

pp. 99-106 ◽

Cited By ~ 8

Author(s):

S.M. Mizanoor Rahman

Keyword(s):

High Speed ◽

Mechanical Design ◽

Spur Gear ◽

Ball Screw ◽

Series Elastic Actuator ◽

Torsional Spring ◽

Dynamics And Control ◽

Manufacturing Techniques ◽

Design Selection ◽

Series Elastic

This paper presents the analysis of electro-mechanical design, selection of materials and manufacturing techniques for physical construction, dynamics, control etc. of a novel variable impedance compact compliant series elastic actuator (SEA) for human-friendly robotics applications. The electro-mechanical design consists of a servomotor, a ball screw, a torsional spring connecting the servomotor and the ball screw via a pair of spur gear, and a set of translational springs connecting the ball screw nut to the output link. The translational springs have low stiffness and these are used to handle low force operations that reduce non-linear friction, output impedance, impact etc. The torsional spring is in the high speed range, has high effective stiffness and it enhances the system bandwidth for large force operations when the translational springs are fully compressed. Suitable materials and appropriate manufacturing techniques for the construction of the actuator are discussed. Kinematics and working principle of the actuator are analyzed. The actuator model is simulated on the physical implementation for dynamics and control for different conditions. Simulation results prove satisfactory performances of the design. Then, advantages of the design over its existing counterparts are discussed, and its potential applications and future extensions are mentioned.

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Gait Phase-Based Control for a Rotary Series Elastic Actuator Assisting the Knee Joint

Journal of Medical Devices ◽

10.1115/1.4004793 ◽

2011 ◽

Vol 5 (3) ◽

Cited By ~ 18

Author(s):

Joonbum Bae ◽

Kyoungchul Kong ◽

Masayoshi Tomizuka

Keyword(s):

Boundary Layer ◽

Knee Joint ◽

Sliding Mode ◽

Human Robot Interaction ◽

Torque Control ◽

Modeling Uncertainty ◽

Series Elastic Actuator ◽

Chattering Phenomenon ◽

Assistive Systems ◽

Series Elastic

Actuators for physical human-robot interaction (pHRI) such as rehabilitation or assistive systems should generate the desired torque precisely. However, the resistive and inertia loads inherent in the actuators (e.g., friction, damping, and inertia) set challenges in the control of actuators in a force/torque mode. The resistive factors include nonlinear effects and should be considered in the controller design to generate the desired force accurately. Moreover, the uncertainties in the plant dynamics make the precise torque control difficult. In this paper, nonlinear control algorithms are exploited for a rotary series elastic actuator to generate the desired torque precisely in the presence of nonlinear resistive factors and modeling uncertainty. The sliding mode control smoothed by a boundary layer is applied to enhance the robustness for the modeling uncertainty without chattering phenomenon. In this paper, the rotary series elastic actuator (RSEA) is installed on the knee joint of an orthosis, and the thickness of the boundary layer is changed by gait phases in order to minimize the torque error without the chattering phenomenon. The performance of the proposed controller is verified by experiments with actual walking motions.

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Design and Preliminary Results of a Reaction Force Series Elastic Actuator for Bionic Ankle Prostheses

10.31224/osf.io/3wt5j ◽

2019 ◽

Cited By ~ 1

Author(s):

Matt Carney ◽

Tony Shu ◽

Roman Stolyarov ◽

Jean-Francois Duval ◽

Hugh Herr

Keyword(s):

Energy Storage ◽

Mechanical Design ◽

Mechanical Energy ◽

Reaction Force ◽

Electrical Energy ◽

Peak Torque ◽

Walking Gait ◽

Series Elastic Actuator ◽

Hardware Specification ◽

Series Elastic

The TF8 actuator is an untethered, lower-extremity powered-prostheses designed to replicate biological kinetic and kinematic function of ankles. An energy optimal hardware specification was found by kinematically clamping walking gait data to the dynamic model of a series elastic actuator (SEA). We searched for a minimal electrical energy configuration of motor, reduction ratio, and spring, subject to specified constraints and ultimately discretely available components. The outcome translated into a mechanical design that heavily weighted the importance of mechanical energy storage in springs. The resulting design is a moment-coupled cantilever-beam reaction-force SEA (RFSEA) that has a nominal torque rating of 85Nm, peak torque of 175Nm, 105 degree range of motion, and a hardware mass of 1.6kg.

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