The manufacturing sector is no stranger to robots. They have changed the way devices are assembled and go beyond basic manufacturing into secondary tasks. Robots are also popping up in the medical industry. For example, researchers at the Robotics Research Lab at the University of Southern California are using them for therapy with autistic children, who are encouraged by mechanical-like repetition. Other “rehabilitation robots” are helping stroke victims walk and regain use of their limbs.

Hands for dangerous work

The creators of Shadow Dextrous Hands hope their robots will change the way we look at difficult, dirty, demeaning, and dangerous jobs. “For example, a pair of hands could be mounted on robot arms in a laboratory and operated by a person wearing datagloves,” says Rich Walker, Technical Director at Shadow Robot Company, London. “The robots could be used in bomb disposal, nuclear activities, and repair in other difficult circumstances.”

The newest Dextrous Hand, the C5, was recently sold to the University of Bielefeld to help research learning techniques for real-world robots. The hand is mainly sold to universities and researchers investigating humanoid robotics, robotic manipulation, and neurology.

The Shadow Hand can perform 24 movements, allowing a direct mapping from a human to robot. It can be controlled from off-board computers, or integrated into existing robot platforms. The C5 contains a bank of 40 air muscles which make it move. The muscles are compliant, which means the hand can be used around soft or fragile objects. It also can be fitted with touch sensing on the fingertips, making it sensitive enough to detect a small coin.

Air muscles consist of a rubber tube covered in tough-plastic netting which shortens in length (like a human muscle) when inflated with compressed air at low pressure. An air muscle has a power-to-weight ratio as high as 400:1, outperforming both pneumatic cylinders and dc motors that can hit ratios of only about 16:1. The air muscle has been in development for advanced robotics work by Shadow since 1982, and is now available for use in a variety of applications as a powerful, lightweight actuator. Air muscles normally operate on air compressed up to as much as 60 psi.

“A small 6-mm diameter air muscle has the strength, speed, and fine stroke of a finger muscle in a human hand,” Walker adds. “An air muscle 30 mm in diameter can lift more than 150 lb at a pressure of only 58 psi, while a large muscle (50 mm) can pull down a brick wall.”

Robotic brace aids stroke recovery

When used under the supervision of an occupational or physical therapist, a robotic therapy brace helps stroke patients progress from basic motor training, such as lifting boxes or reaching for a light switch, to more complex tasks such as carrying a laundry basket or flipping on a light switch.

The lightweight, robotic brace, developed by MIT engineers, slides onto the arm. It senses a patient's electrical muscle activity through the surface of the skin. The data is sent to a motor, which provides power assistance to facilitate movements.

Following a stroke, the destruction of brain cells leads to loss of motor function. With painstakingly repetitive exercise therapy, other neurons can take over some of the lost function. Devices such as the MIT-developed robotic brace can help people exploit their neural plasticity — the ability of the brain to rewire itself in response to experience and training.

The robotic-therapy device, which is awaiting FDA approval, was tested on stroke patients at MIT's Clinical Research Center and at Spaulding Rehabilitation Hospital in Boston. According to researchers, results show that “the ability of the device to provide a ‘power assist’ to muscle groups may help close the feedback loop of brain intention and actual limb movement. This is believed to be a key component of cerebral plasticity in motor recovery.”

The study says that severely impaired arm function improved, on average, 23% after using the brace. In addition, arm muscle tightness, typical in stroke victims, significantly reduced.

“This brace will let people who have suffered from neurological trauma rebuild strength, rehabilitate, and gain independence,” says Woodie Flowers, Pappalardo Professor of Mechanical Engineering at MIT, who led the original research team that developed the device. “The joint brace is easily controlled by the user and appears to be cost-effective.”

In 2002 and 2003, Flowers, along with then-students Kailas Narendran and John McBean, developed a working prototype of the active joint brace. The first prototype system let paralyzed victims with certain kinds of spinal cord injuries move their arms. In 2004, Narendran and McBean started the Boston-based company Myomo (an acronym for “my own motion”) to develop a new class of medical technology they call NeuroRobotics.

“NeuroRobotics noninvasively helps people suffering from neurological trauma regain mobility by making it easy to relearn how to control affected muscles and neurological pathways,” Narendran says.

“Unlike other systems that stimulate or move the muscle for a patient, NeuroRobotics is embedded in lightweight wearable devices that actually adjust to a person's body and use the person's own electrical muscle activity signal to initiate and control movement,” McBean says.

“Without the device, many of the individuals we tested were simply unable to complete a movement, and therefore had no practical way to improve their performance through practice,” the researchers say. “The device helps complete an intended movement through its ‘power assist’ function, thereby improving the user's performance through practice.”

Robotic catheters guide doctors through the heart

A robotic system makes it easy for doctors to manipulate catheters in hard-to-reach places within the heart. The Sensei Robotic Catheter System from Hansen Medical Inc., Mountain View, Calif., accurately controls catheter movement during cardiac procedures.

The company recently announced the successful completion of a 20-patient prospective trial and follow-up using the Sensei system to guide catheters for mapping heart anatomy, a critical step in identifying heart tissue that generates abnormal heart rhythms. Data from the follow-up showed no device-related adverse events.

Currently, cardiac electrophysiology procedures are performed using a manual technique that requires a physician to perform a series of complex manipulations at one end of the catheter with no assurance that the tip of the catheter will respond as needed while inside a patient's heart. As a result, it is difficult to get stable contact at every anatomic site within the heart, which is necessary for successful mapping. Insufficient contact between the catheter tip and the inside of the heart wall can lead to highly variable and less than the best outcomes.

To date, 83 cardiac procedures have been performed on patients in Europe using the Sensei system. The technology combines fluoroscopic, intracardiac ultrasound, 3D surface mapping, and patient electrocardiogram data into a portable workstation. It is easily moved among catheter lab suites and does not require a costly specialized room.

The robotic catheter lets doctors work in three dimensions from a remote location and even while sitting down. This gives them better control over catheter placement, as well as potentially decreasing procedure times and radiation exposure.

“There is a medical need for broader use of catheter-based procedures for diseases where catheters are rarely used today,” says Hansen founder and CEO Frederic Moll. “Our robotic platform will let more physicians perform complex interventional procedures through greater ease of use, and possibly improve patient outcomes,” he adds.

Make contact

Center for Robotics and Embedded Systems at the University of Southern California
cres.usc.edu/Home
Hansen Medical Inc.
hansenmedical.com
MIT lab for biomechanics and human rehabilitation
web.mit.edu/hogan/www/
Myom omyomo.com
Shadow Robot Company
shadowrobot.com