A novel robot for arm motor therapy with homogeneous mechanical properties

Robotic platforms developed to assist conventional motor therapy and to investigate human motor control have received an increasing interest over the past decades. However, for most of the proposed solutions, bulkiness and expensiveness have limited the use of such devices to specialized clinics that can afford their cost. This paper presents the H-Man, a two degree-of-freedom planar device designed according to three main principles: cost-effectiveness, portability and ease of control. The key component of the device is a planar H-shaped cable differential mechanism which ensures a constant Jacobian and homogeneous perceived inertia over the entire workspace. The paper presents the mechanical design as well as the performance evaluation in terms of perceived impedance.