Rory Cooper’s Wheelchair Tech Makes the World More Accessible

He has introduced customized controls and builds wheelchairs for rough terrain

6 min read
portrait of a man in a navy blue polo with greenery in the background
Abigail Albright

For more than 25 years, Rory Cooper has been developing technology to improve the lives of people with disabilities.

Cooper began his work after a spinal cord injury in 1980 left him paralyzed from the waist down. First he modified the back brace he was required to wear. He then turned to building a better wheelchair and came up with an electric-powered version that helped its user stand up. He eventually discovered biomedical engineering and was inspired to focus his career on developing assistive technology. His inventions have helped countless wheelchair users get around with more ease and comfort.


Technologies that Cooper has developed include the SmartWheel and the VCJ-CA, a variable-compliance joystick with compensation algorithms. The SmartWheel attaches to a manual wheelchair to measure the force of pushes, push frequency, stroke length, smoothness, and speed of both the push and the wheelchair. Wheelchair athletes use the data to optimize their performance. It is also helpful in determining adjustments to minimize stress injuries for more typical users. The VCJ-CA lets users customize the driving controls of electric-powered wheelchairs and is used today in just about every such chair.

These days, Cooper and his team at the University of Pittsburgh’s Human Engineering Research Laboratories are working to develop advancements including a wheelchair that can travel on rough terrain. Cooper founded the HERL in collaboration with the U.S. Department of Veterans Affairs.

About Rory Cooper

Employer Human Engineering Research Laboratories at the University of Pittsburgh

Title Director

Member grade Life Fellow

Alma mater California Polytechnic State University, in San Luis Obispo.

For those and other “extensive contributions to wheelchair technology that have expanded mobility and reduced secondary injuries for millions of people with disabilities,” Cooper received this year’s IEEE Biomedical Engineering Award.

The award “recognizes the importance of the work I and other engineers do,” he says, adding that he is humbled by the honor. The award also recognizes that “people with disabilities are an important part of our society. Hopefully [my receiving this honor] encourages other people to continue the work being done in this field.”

Cooper himself is not done yet. He says that although technology, medicine, and society have evolved significantly in the way they can help people with disabilities, “there’s still a lot of opportunity for technology to further improve people’s lives and health.” And, as HERL director and a professor of bioengineering, physical medicine, rehabilitation, and orthopedic surgery at the University of Pittsburgh, he plans to develop more helpful tools.

Changing the course of his career

The bicycle accident that damaged Cooper’s spine happened while he was stationed in Germany in his fourth year with the U.S. Army. He left the Army soon after and returned to the United States, earning a bachelor’s degree in 1985 in electrical engineering from California Polytechnic State University, in San Luis Obispo. He went on to receive a master’s degree from Cal Poly in the same subject in 1986, taking classes while working as an instrumentation and control engineer at Pacific Gas and Electric in Diablo Canyon, Calif. During his graduate studies, at the recommendation of a friend, he took a biomedical engineering class and fell in love with the field, he says. He also had started teaching apprentices at PG&E the basics of control systems and electronics—which provided another type of inspiration.

Educating the apprentices “was a great thing for me and perhaps a mistake for PG&E because I found that I really enjoyed teaching,” Cooper says, laughing.

Thinking he’d rather teach than continue an industry career as he had planned, he headed to the University of California, Santa Barbara, for a Ph.D. There he began developing a device that came to be called the SmartWheel. The mechanical instrument has a complex set of sensors integrated with a single-board computer with wireless communication. SmartWheels are mounted onto wheelchairs.

“I started to develop the technology because I wanted to try to win a medal in the Paralympics,” Cooper says. “SmartWheel measures the wheelchair’s propulsion dynamics, and I could use the data collected to optimize the biomechanics of my wheelchair and my body motions.”

The SmartWheel measures the forces and torques applied by athletes to the push rim (the part on the chair individuals use to turn the wheels). An encoder measures the wheel’s speed and orientation. Athletes can use the data to optimize their performance by adjusting their body position, customizing the design of their chair, and positioning and orienting their wheels with respect to their shoulders.

It worked for him: He received a bronze Paralympic medal in wheelchair racing in 1988.

But Cooper hadn’t perfected the device when, after graduation in 1989, he joined California State University in Sacramento as a faculty member.

Then he met Charles Robinson at an IEEE conference that year in Seattle. The IEEE Life Fellow was a rehabilitation research career scientist in the Department of Veterans Affairs. He invited Cooper to join his team as a postdoctoral researcher. Cooper accepted the position and worked both jobs for approximately five years.

Cooper eventually left Cal State while continuing to work part time at the VA. In 1994 he joined the University of Pittsburgh as a professor, establishing the HERL that year to develop and enhance technology that promotes people’s mobility, function, and inclusion.

“The lab started with me and two graduate students,” he says, “and now about 70 engineers, clinicians, researchers, and students are working on projects.”

One of those projects was continuing development of the SmartWheel. The device became commercially available in 2000 and was used by the U.S. Paralympic athletes during training for the 2021 games in Tokyo.

Cooper and fellow researchers saw unintended health benefits for manual wheelchair users who employed a SmartWheel. It can help reduce carpal tunnel syndrome and rotator cuff injuries, he says. SmartWheels are now commonly used by physical therapists in more than 100 clinics to optimize wheelchair setup and push style to reduce repetitive stress injuries, he says.

Making electric-powered wheelchairs inclusive

HERL researchers have produced many life-changing advancements.

“One technology that I’m particularly proud of is the variable-compliance joystick with compensation algorithms,” Cooper says. Before the VCJ-CA was invented, the controls of electric-powered wheelchairs were analog, not digital. It was difficult to customize a wheelchair that had analog controls, he says. If the user had even the slightest tremor or tic, the wheelchair could move unintentionally. Many people needed someone to operate the wheelchair for them, he says.

“There were a lot of people who were reliant on others to push their wheelchair or to operate its controls for them,” Cooper says. “But these wheelchair users wanted independent mobility, so I began studying how to make this possible.”

The VCJ-CA is a joystick whose hardware and software can be customized to fit each user’s needs. For example, individuals with restricted hand or arm movement can tailor the stiffness of the joystick according to their reach, strength, and control. The algorithms allow individuals to customize their wheelchair’s speed, braking, acceleration, and turning capabilities. The algorithms also can adapt to a user’s tremor, range of motion, ability to generate motion or force, and ability to control the direction of their arm, hand, or finger.

“The VCJ-CA is now used in almost every electric-powered wheelchair in the world—which is pretty cool,” Cooper says. “People who were dependent upon others can now drive independently.”

Bringing stability and safety to wheelchair users

3 people sitting in wheelchairs and 1 man standingCooper (second from the left) and his colleagues—David Constantine, Jorge Candiotti, and Andrin Vuthaj (standing)—at the University of Pittsburgh’s Human Engineering Research Laboratories working on the MEBot.Abigail Albright

The most common cause of emergency-room visits by wheelchair users is falling from the chair or tipping over, Cooper says.

“This often happens when the individual’s wheelchair hits thresholds in doorways, drives off small curbs, or transitions from a sidewalk to a ramp,” he says.

Since 2013, he and his team have been working on the Mobility Enhancement Robotic Wheelchair to minimize such injuries.

Known as the MEBot, the wheelchair can climb curbs up to 20 centimeters high and can self-level as it drives over uneven terrain. It does so thanks to six wheels that move up and down plus two sets of smaller omnidirectional wheels in the front and back. The wheelchair’s larger, powered wheels can reposition themselves to simulate front-, mid-, or rear-wheel drive.

User trials were completed last year. Cooper says the team received positive feedback, and one individual compared it to riding a magic carpet. The MEBot will become available within the next five years, Cooper predicts.

The importance of IEEE

Cooper joined IEEE as a Cal Poly freshman. The university’s engineering department had a study room specifically for IEEE student members, he says.

“It was a good place for me to study, because everyone there was pursuing a degree in electrical engineering,” he says. “The professors at Cal Poly would also often approach IEEE student members to join their research and development teams.”

After graduation, he began attending IEEE conferences and publishing papers in the organization’s journals. He has become more active during his four decades as a member. He has served as a senior associate editor of theIEEE Transactions on Neural Systems and Rehabilitation Engineering, for example, and he is a member of the IEEE Engineering in Medicine and Biology Society’s standards committee.

He says he maintains his membership partly because IEEE produces “great publications, enhances education, and works on standards that change people’s lives.”

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The Inner Beauty of Basic Electronics

Open Circuits showcases the surprising complexity of passive components

5 min read
Vertical
A photo of a high-stability film resistor with the letters "MIS" in yellow.
All photos by Eric Schlaepfer & Windell H. Oskay
Blue

Eric Schlaepfer was trying to fix a broken piece of test equipment when he came across the cause of the problem—a troubled tantalum capacitor. The component had somehow shorted out, and he wanted to know why. So he polished it down for a look inside. He never found the source of the short, but he and his collaborator, Windell H. Oskay, discovered something even better: a breathtaking hidden world inside electronics. What followed were hours and hours of polishing, cleaning, and photography that resulted in Open Circuits: The Inner Beauty of Electronic Components (No Starch Press, 2022), an excerpt of which follows. As the authors write, everything about these components is deliberately designed to meet specific technical needs, but that design leads to “accidental beauty: the emergent aesthetics of things you were never expected to see.”

From a book that spans the wide world of electronics, what we at IEEE Spectrum found surprisingly compelling were the insides of things we don’t spend much time thinking about, passive components. Transistors, LEDs, and other semiconductors may be where the action is, but the simple physics of resistors, capacitors, and inductors have their own sort of splendor.

High-Stability Film Resistor

A photo of a high-stability film resistor with the letters "MIS" in yellow.

All photos by Eric Schlaepfer & Windell H. Oskay

This high-stability film resistor, about 4 millimeters in diameter, is made in much the same way as its inexpensive carbon-film cousin, but with exacting precision. A ceramic rod is coated with a fine layer of resistive film (thin metal, metal oxide, or carbon) and then a perfectly uniform helical groove is machined into the film.

Instead of coating the resistor with an epoxy, it’s hermetically sealed in a lustrous little glass envelope. This makes the resistor more robust, ideal for specialized cases such as precision reference instrumentation, where long-term stability of the resistor is critical. The glass envelope provides better isolation against moisture and other environmental changes than standard coatings like epoxy.

15-Turn Trimmer Potentiometer

A photo of a blue chip
A photo of a blue chip on a circuit board.

It takes 15 rotations of an adjustment screw to move a 15-turn trimmer potentiometer from one end of its resistive range to the other. Circuits that need to be adjusted with fine resolution control use this type of trimmer pot instead of the single-turn variety.

The resistive element in this trimmer is a strip of cermet—a composite of ceramic and metal—silk-screened on a white ceramic substrate. Screen-printed metal links each end of the strip to the connecting wires. It’s a flattened, linear version of the horseshoe-shaped resistive element in single-turn trimmers.

Turning the adjustment screw moves a plastic slider along a track. The wiper is a spring finger, a spring-loaded metal contact, attached to the slider. It makes contact between a metal strip and the selected point on the strip of resistive film.

Ceramic Disc Capacitor

A cutaway of a Ceramic Disc Capacitor
A photo of a Ceramic Disc Capacitor

Capacitors are fundamental electronic components that store energy in the form of static electricity. They’re used in countless ways, including for bulk energy storage, to smooth out electronic signals, and as computer memory cells. The simplest capacitor consists of two parallel metal plates with a gap between them, but capacitors can take many forms so long as there are two conductive surfaces, called electrodes, separated by an insulator.

A ceramic disc capacitor is a low-cost capacitor that is frequently found in appliances and toys. Its insulator is a ceramic disc, and its two parallel plates are extremely thin metal coatings that are evaporated or sputtered onto the disc’s outer surfaces. Connecting wires are attached using solder, and the whole assembly is dipped into a porous coating material that dries hard and protects the capacitor from damage.

Film Capacitor

An image of a cut away of a capacitor
A photo of a green capacitor.

Film capacitors are frequently found in high-quality audio equipment, such as headphone amplifiers, record players, graphic equalizers, and radio tuners. Their key feature is that the dielectric material is a plastic film, such as polyester or polypropylene.

The metal electrodes of this film capacitor are vacuum-deposited on the surfaces of long strips of plastic film. After the leads are attached, the films are rolled up and dipped into an epoxy that binds the assembly together. Then the completed assembly is dipped in a tough outer coating and marked with its value.

Other types of film capacitors are made by stacking flat layers of metallized plastic film, rather than rolling up layers of film.

Dipped Tantalum Capacitor

A photo of a cutaway of a Dipped Tantalum Capacitor

At the core of this capacitor is a porous pellet of tantalum metal. The pellet is made from tantalum powder and sintered, or compressed at a high temperature, into a dense, spongelike solid.

Just like a kitchen sponge, the resulting pellet has a high surface area per unit volume. The pellet is then anodized, creating an insulating oxide layer with an equally high surface area. This process packs a lot of capacitance into a compact device, using spongelike geometry rather than the stacked or rolled layers that most other capacitors use.

The device’s positive terminal, or anode, is connected directly to the tantalum metal. The negative terminal, or cathode, is formed by a thin layer of conductive manganese dioxide coating the pellet.

Axial Inductor

An image of a cutaway of a Axial Inductor
A photo of a collection of cut wires

Inductors are fundamental electronic components that store energy in the form of a magnetic field. They’re used, for example, in some types of power supplies to convert between voltages by alternately storing and releasing energy. This energy-efficient design helps maximize the battery life of cellphones and other portable electronics.

Inductors typically consist of a coil of insulated wire wrapped around a core of magnetic material like iron or ferrite, a ceramic filled with iron oxide. Current flowing around the core produces a magnetic field that acts as a sort of flywheel for current, smoothing out changes in the current as it flows through the inductor.

This axial inductor has a number of turns of varnished copper wire wrapped around a ferrite form and soldered to copper leads on its two ends. It has several layers of protection: a clear varnish over the windings, a light-green coating around the solder joints, and a striking green outer coating to protect the whole component and provide a surface for the colorful stripes that indicate its inductance value.

Power Supply Transformer

A photo of a collection of cut wires
A photo of a yellow element on a circuit board.

This transformer has multiple sets of windings and is used in a power supply to create multiple output AC voltages from a single AC input such as a wall outlet.

The small wires nearer the center are “high impedance” turns of magnet wire. These windings carry a higher voltage but a lower current. They’re protected by several layers of tape, a copper-foil electrostatic shield, and more tape.

The outer “low impedance” windings are made with thicker insulated wire and fewer turns. They handle a lower voltage but a higher current.

All of the windings are wrapped around a black plastic bobbin. Two pieces of ferrite ceramic are bonded together to form the magnetic core at the heart of the transformer.

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