Survivors of cancerous and traumatic transpelvic amputations have difficulty in transitioning into and out of a chair, as well as sitting upright with correct posture. The addition of special pads and chair inserts can help the amputee; however, through time, the amputee may develop spinal deformities, which pose a major health concern. In an effort to improve the quality of life of transpelvic amputees, a representative single-axis hip-joint prosthesis analogue is designed and tested. A motor, loaded with mass characteristics similar to that of a plausible thigh prosthesis, performs bidirectional motion; it is commanded by an embedded controller that calculates position commands from two body-mounted IMUs. Body acceleration data is obtained from the IMUs, and real-time calculations are performed to generate positional commands for the hip-joint motor. A 3-D motion camera system confirms that digital data obtained from system measurement devices accurately corresponds to the physical position and orientation of the body and representative prosthesis. A separate computer is used to simultaneously log raw data, generate data analysis visuals, and produce system stability and response characteristics. After completing a thorough analysis of the system's operation and response, the prosthesis analogue produces motion and control characteristics feasible for autonomous electromechanical prosthesis motion. The study, as a whole, successfully presented a control system that measures data accurately from body-mounted IMUs and controls a closed-feedback, single-axis, rotational device, representative of a plausible electromechanical thigh-joint prosthesis. With further research towards a complete prosthesis prototype, system design, and control characteristics of this study could be integrated and used in the advancement of the quality of life of many transpelvic amputation survivors.