A prototype wearable exoskeleton having three degrees of freedom is presented in this paper. The design considers multiple user acceptance criteria and functional requirements with the aim to facilitate robotic-assisted in-home rehabilitation therapy. Actuation modules containing shape memory alloy (SMA) wires, mechanical amplification and position sensors are designed to meet work requirements during activities of daily living. Modules containing differential configuration and spring bias configuration are built and presented. Kinematic and dynamic models are presented. A simplified material model which relates the system inputs to the SMA strain rate is derived and validated using open loop tracking results. This is combined with a gain scheduled servo-loop for disturbance rejection to create a feedforward controller. Mo dules and controller showed reasonable results tracking sinusoidal trajectories, with friction and controller parameters contributing to velocity instability. The theory of stiffness control in differential configuration and the requirement for control of the heating and cooling rates is presented. Miniature fans are fitted to control the cooling rate however this was unsuccessful probably due to the dominance of conduction heat transfer within the design. The modular actuators are tested while extracted from the exoskeleton design. The results lead to the conclusion that the following aspects require improvement before testing proceeds on a user: 1) integration of force sensors into the control loop, 2) hardware which improves the controlled cooling rate, 3) qualitative analysis of friction in the system.