Alexander Makhlin

KineAssist: a robotic overground gait and balance training device

The KineAssist is a robotic device for gait and balance training. A user-needs analysis led us to focus on increasing the level of challenge to a patients ability to maintain balance during gait training, and also on maintaining direct involvement of a physical therapist (rather than attempting robotic replacement.) The KineAssist provides partial body weight support and postural torques on the torso; allows many axes of motion of the trunk as well as of the pelvis; leaves the patients legs accessible to a physical therapist during walking; servo-follows a patients walking motions overground in forward, rotation, and sidestepping directions; and catches a patient who begins to fall. Design and development of the KineAssist proceeded more rapidly in the context of a small company than would have been possible in most research contexts. A prototype KineAssist has been constructed, and has received FDA approval and IRB clearance for initial human studies. We describe the KineAssists motivation, design, and use.

On the Design of Miniature Haptic Devices for Upper Extremity Prosthetics

We have developed three different versions of a multifunction haptic device that can display touch, pressure, vibration, shear force, and temperature to the skin of an upper extremity amputee, especially the one who has undergone targeted nerve reinnervation (TR) surgery. In TR patients, sensation from the reinnervated skin is projected to the missing hand. This paper addresses the design of the mechanical display, the portion responsible for contact, pressure, vibration, and shear force. A variety of different overall design approaches satisfying the design specifications and the performance requirements are considered. The designs of the fully prototyped haptic devices are compared through open-loop frequency response, closed-loop force response, and tapping response in constrained motion. We emphasize the tradeoffs between key design factors, including force capability, workspace, size, bandwidth, weight, and mechanism complexity.

A Miniature Tactor Design for Upper Extremity Prosthesis

We have been developing a miniature haptic device - a tactor that can display pressure, vibration, shear force, and temperature to the skin of upper extremity amputees, especially those who have undergone targeted nerve rein-nervation (TRI) surgery. In TRI patients, regions of the rein-nervated skin are perceived as being on the phantom hand. This paper presents the mechanical design of the tactor.