Rehabilitation glove uses artificial muscles
November 7, 2004 A rehabilitation glove powered by artificial muscles has won the recent AUD $10,000 British Council Eureka Prize for inspiring science. Designed by the Quadriplegic Hand Research Unit at the Royal North Shore Hospital, the invention will help people with permanent hand-movement loss to perform the daily functions most of us take for granted.
The Australian design is the first medical application to use dynamic actuators that contract when stimulated in a similar way to normal muscles. It opens up new therapeutic possibilities for those suffering from paralysed hands and future applications may even see artificial muscles implanted in the body to enable bionic functionality.
Currently one of the most effective ways to rehabilitate damaged hands or to maintain supple conditions for paralysed hands is by a gentle, continuous motion of hand joints. This often requires intensive attention over long periods, making it unfeasible for a therapist to be continuously present.
With the rehabilitation glove each joint can be independently moved to a desired angle. Portable control software allows the therapist to program desired force, speed and range of motion for each of the15 finger/ thumb joints in the hand, giving continuous passive joint movements for hours at a time.
The Rehabilitation Glove will provide a light hand grasp with a controllable holding force. For people with paralysed hands, this function can be triggered using an external switch. This beneficial feature allows the device to control and maintain a grasp force, thereby securing the grip on objects held.
The prototype is currently using tiny linear piezoelectric actuators that emulate muscle action by pulling artificial tendons embedded in the glove. Actuator activation is controlled by a Pocket PC, thereby enabling portability. Artificial proprioception is provided for the joints using specially designed force/position transducers. A software interface, designed to be clinician friendly, is used to program desired passive movement.
Using biofeedback sensors the system software has the ability to log the performance of the hand through time. This function can monitor the effectiveness of the therapy as well as continuously adjust the exercises to increase performance.
The Rehabilitation Glove will help limit time spent in hospitals and in outpatient based therapy by decreasing the problems associated with immobility and the consequent swelling of the hand. Quadriplegics or stroke victims who have no neural connection to their hand muscles will be able to grasp objects, feed themselves, brush their teeth, pick up the telephone and shake hands without the need for surgical implants of stimulation chips.
There are possibilities for using polymers that contract like muscles when activated in the near future. Artificial Muscles have a great potential for use within the medical and rehabilitative field. These actuators have an advantage over traditional motors, being lighter, smaller in volume, more efficient and able to emulate the natural function of muscles. In the future this technology may also be implantable, providing a more cosmetic solution to muscular dysfunction.