End-point position control of a single-link arm using shape memory alloy actuators

This article presents a novel type of actuating mechanism for the end-point trajectory control of a single-link system. The actuating mechanism consists of two sets of shape memory alloy (SMA) springs to generate a desired link motion of the system. The governing equation of motion is derived using the Lagrangian equation and Jacobian matrix. The actuator dynamic of the SMA spring is then empirically identified and incorporated into the governing equation. A sliding mode controller that is robust to parameter variations such as the time constant of the SMA actuator is formulated to achieve desired end-point trajectories of the single-link system. The controller is experimentally realized and tracking control performances for various end-point position trajectories are presented. In addition, the simulated control results are compared with the measured ones in order to validate the proposed control model.

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Angular control of differential shape-memory alloy spring actuator for underactuated dynamic system

Journal of Vibration and Control ◽

10.1177/10775463211021670 ◽

2021 ◽

pp. 107754632110216

Author(s):

M Banu Sundareswari ◽

G Then Mozhi ◽

K Dhanalakshmi

Keyword(s):

Shape Memory Alloy ◽

Shape Memory ◽

Fractional Order ◽

Position Control ◽

Sliding Mode ◽

Control Effort ◽

Control Laws ◽

Integer Order ◽

Two Degree Of Freedom ◽

Outer Primary

This article dwells on two technical aspects, the design and implementation of an upgraded version of the differential shape-memory alloy–based revolute actuator/rotary actuating mechanism for stabilization and position control of a two-degree-of-freedom centrally hinged ball on beam system. The actuator is configured with differential and inclined placement of shape-memory alloy springs to provide bidirectional angular shift. The shape-memory alloy spring actuator occupies a smaller space and provides more extensive reformation with justifiable actuation force than an equally able shape-memory alloy wire. The cross or diagonal architecture of shape-memory alloy springs provides force amplification and reduces the actuator’s control effort. The shape-memory alloy spring–embodied actuator’s function is exemplified by the highly dynamic underactuated custom-designed ball balancing system. The ball position control is experimentally demonstrated by cascade control using the control laws that have been unattempted for shape-memory alloy actuated systems; the ball is positioned with linear (integer-order and fractional-order) proportional–integral–derivative controllers optimized with genetic algorithm and particle swarm optimization at the outer/primary loop. Angular control of the shape-memory alloy actuated beam is obtained with nonlinear (integer-order and fractional-order sliding mode control) control algorithms in the inner/secondary loop.

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Robust position regulation of a shape memory alloy wire actuator

Proceedings of the Institution of Mechanical Engineers Part I Journal of Systems and Control Engineering ◽

10.1177/095965180221600308 ◽

2002 ◽

Vol 216 (3) ◽

pp. 301-308 ◽

Cited By ~ 2

Author(s):

G Song

Keyword(s):

Shape Memory Alloy ◽

Shape Memory ◽

Position Control ◽

High Strain ◽

Sliding Mode ◽

Recovery Stress ◽

High Recovery ◽

Robust Controller ◽

Alloy Wire ◽

Position Regulation

This paper presents design and experiment results of active position control of a shape memory alloy (SMA) wire actuator using a sliding mode based robust approach. In this research, an SMA wire was chosen as an actuating element for position control owing to its high recovery stress (gt;500MPa) and tolerance to high strain (up to 5 per cent). To compensate for the inherent non-linearity associated with the SMA, a sliding mode based robust controller was designed and implemented actively to control the position of the SMA wire actuator. Experiments demonstrated the effectiveness of the robust control. For a 12 in long SMA wire actuator, the position can be controlled within 30m.

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Adaptive Fuzzy Sliding-Mode Position Control of a Shape Memory Alloy Actuated System

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.789-790.946 ◽

2015 ◽

Vol 789-790 ◽

pp. 946-950

Author(s):

Suwat Kuntanapreeda

Keyword(s):

Shape Memory Alloy ◽

Shape Memory ◽

Position Control ◽

Sliding Mode ◽

Control Loop ◽

Adaptive Fuzzy ◽

Sma Actuators ◽

Control Scheme ◽

Adaptive Fuzzy Sliding Mode ◽

Fuzzy Sliding Mode

Shape memory alloy (SMA) actuators are promising for miniature applications. They accomplish the shape memorization via a temperature dependent phase transformation process. Control of SMA actuators is challenging because the actuators exhibit highly hysteresis behavior. This paper presents a fuzzy-based position control scheme for a SMA actuated mass system. The control system consists of an outer-and an inner-control loop. The inner loop controls the temperature of the SMA actuators using a PI controller, whereas the outer loop, which is affected by the hysteresis of the SMA actuators, controls the position. To deal with the hysteresis in the position control loop, an adaptive fuzzy sliding-mode control method is adopted. Experimental results illustrate the success of the proposed control scheme.

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