This paper presents a technological solution for designing an assistive device for a biomechanical study of the Sit-to-Stand movement (STS). This device targets people with disabilities following a stroke. The control algorithms are implemented in TwinCAT runtime environment. The communication between all the component and the control computer is ensured via the EtherCAT fieldbus. The aim of this architecture lies in the fact that it allows a quick development of a research prototype with the same safety issues found on an industrial machine. An experimental test of the STS strategy is presented.