B-Spline Based Adaptive Control of Shape Memory Alloy Actuated Robotic Systems

Abstract

In this paper we present a novel controller for Shape Memory Alloy (SMA) actuated robotic systems. The new controller, called BAC (B-spline based Adaptive Control), is based on a hybrid combination of gain scheduling, B-spline approximation, variable structure control and integral control. The proposed controller shows excellent positioning accuracy and speed throughout the full range of motion of a SMA actuated robotic system in large-scale applications. To demonstrate the validity of BAC, a novel anthropomorphic SMA Actuated forearm/wrist mechanism is utilized in real-time PC based control experiments. BAC is experimentally compared to PID and integral variable structure controllers and it is shown that its performance is superior.

Smart Actuation and Sensing Systems - Recent Advances and Future Challenges

“…Currently, the use of SMAs in biomimetic robotic systems [3], [13], [9] can be found in ground, water and air robots, in many sizes, including those micro-robots or microstructures [25], [78], [53], [35], [63], [82], [37], [37].…”

Memory alloy actuator

“…The equations defining this block are found by solving for temperature difference, θ, in the phase kinetics equations in (3) - (6). The general form of the inverse model output equation is given in (7).…”

“…Dickinson and Wen [4] use adaptive feedback control to control an SMA attached to a beam. Variable stucture control is used by Grant et al [10] and Elahinia et al [5] who use variable structure control on an SMA actuated manipulator and Eren et al [6] use a hybrid combination of gain scheduling, B-spline approximation, variable structure control and intergral control. Other [3] who use hysteresis compensation using phasors for piezoelectric actuators, Song and Quinn [23] who use a sliding mode based robust controller.…”

Natural Heat-Sinking Control Method for High-Speed Actuation of the SMA

“…There are other control methods proposed in conventional research efforts [Eren, Y. et.al, 2002] and [Elahinia, M.H. & Ashrafiuon, H., 2002] which involve heating of the alloy in a gradual and slow manner which is inefficient and results in heating up the alloy excessively.…”