Design Methodology for the Development of a New Powered Humeral Rotator for High-Functionality Myoelectric Prostheses

The upper limb amputees with a high level amputation, e.g. a shoulder disarticulation, would require prostheses with high functionality features (in terms of joint mobility and velocity, overall workspace and payload…) in order to autonomously carry out the main activities of daily living. The current commercial solutions prove to be inadequate to satisfactorily rehabilitate most of these patients, mainly due to their restricted workspace (e.g. no prosthetic shoulder articulations are available on the market). Our group is working to develop new high-functionality prostheses. In particular, this study deals with the development of a new powered humeral rotator that should integrate the current upper limb prosthesis available at our labs, which is already provided with a terminal device, a wrist rotator, an elbow joint and a prototype of shoulder articulation – composed of two powered revolute joints – that act as a humeral pointer. This paper focuses on the design methodology that we followed to retrieve the design input data necessary for the development of the new powered humeral rotator. The methodology is mainly based on kinematic and kinetostatic analyses of multibody models of upper limb prostheses.