Robotic System to Facilitate Rehabiltation of Stroke Victims' Limbs

The ARC3D system, introduced by D.L. Rehab Technology, is a new type of robotic system used to facilitate rehabiltation of stroke victims’ limbs. This assistive technology system, consisting of a Haptic Master with a Biodex chair, allows free movement while supporting the user’s arm weight.

A breakthrough in the medical device design technology, this assistive technology is a result of the combined efforts of Jules Dewald, associate professor of Physical Therapy and Human Movement Sciences, Physical Medicine, and Rehabilitation and Biomedical Engineering at Northwestern University and Wim Lam, owner and general manager of Lam Design Management.

Healthy people can indulge in typical arm movements with ease, lifting their arms against gravity and moving their joints independently while holding their arms away from their bodies. However, stroke victims can only drive one joint at a time. If they lift an arm, they also flex the elbow, wrist and fingers, pulling their hand into their chest. This makes it very difficult for them to extend their elbows.

The ARC3D system creates a virtual world where the weight of a stroke victim’s arm can be eliminated and then grdually reintroduced. The robot eliminates the weight of the upper limb, making it easier for the subject to reach out.

This assistive technology system has been developed using two existing pieces of rehabilitation equipment with a new interface, around the JR3 load cell - the first 3D Arm Coordinated Training - which is the key to the end effector. It has a customized interface with a sensor of 4.5 x 1.50in and 100-lb load cell integrated into the end effector.

The second vital part of the system is the chair, made by Biodex Medical Devices, which enables the subject with a high level of control and repeatability for orientation with the HapticMaster. It requires only one axis of rotation, has an adjustable seat and accommodates different-sized individuals.

This combination of the Biodex chair and the HapticMaster robot created the ACT3D system.

How it Works

The system creates a virtual world and responds to the movements of the user. As the user pushes the robot load cell, it senses the force and activates the system.

The system’s video interface gives the user a realistic feel to the objects in the virtual environment. The interface supports the limbs and is connected to a gimble, which is connected to the load cell and the tip of the robot and measures force and torque to give a rigid splint support to the user’s forearm.

The system continually monitors the limb position and provides real-time display of the information. The user can aim at highly targeted strength training with a gradual increase in arm weight. Over time, the user can make his arms heavier to the point that he can deal with the real weight of his arms. The video interface allows the user to monitor his progress and compare data over a period of time.

Source: Device Link