Experimental design, development and visual-servoing of a shape memory alloy actuated finger

In this paper an experimental study on the design, development and visual-servoing of a shape memory alloy (SMA) actuated finger is presented. The SMA have been utilized as tendons for the production of a satisfactory, in terms of workspace and actuation times, human-like actuated finger. This manipulator has two rotational degrees of freedom and its main objective is to control the position of the end-tip. The special characteristics and properties of the SMA have been taken under consideration and all inherent non-linearities and saturations have been embedded in the development modelling and control application. Decoupled PD-controllers provide the command input, while the sensory information is provided through a monoscopic vision system. This visual-servoing scheme drives the manipulator's tip at specified trajectory positions. The final construction is a lightweight, compact device, while the experimental results prove the efficacy and the usability of the overall design and implementation process.