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Leading a "Charged" Life

Today's Power Chairs Are Expected to Do It All — But How Will They Keep Up with Consumers' Powerful Demands?

Power demands on power wheelchairsNot too long ago, power wheelchairs were expected to provide… mobility.

But power wheelchair technology has advanced rapidly, even exponentially, and today’s power chairs are being called upon to provide complex positioning, support ventilators, run augmentative communications devices, and recharge consumer electronics, such as smartphones and tablets.

So how are today’s power wheelchairs answering the call for more power? And what will the next consumer demands be?

More “Powerful” Designs?

Given all the changes in functions that today’s power wheelchairs are expected to perform, you’d think their designs would be radically impacted. But that’s not necessarily so.

Asked how the increasing need for power has affected the design of the company’s power wheelchairs, Rob Travers, VP of marketing & sales for Amysystems, says, “None whatsoever. Different battery sizes with different power outputs exist to accommodate each user’s needs. We can accommodate all types.”

Andrew Kwarciak, accessories & aftermarket specialist for Permobil, says the manufacturer’s mobility bases are successfully powering a range of devices, but that the company is also anticipating future needs.

“[We are] looking for ways to make power for peripheral devices more accessible,” he confirms. “Our power bases have been able to provide power to a number of added devices; however, now we’re working on ways to make it easier for users to take advantage of that power. We’re also thinking of ways to expand the range of available power to cover the growing number of devices each of us use on a daily basis.”

Mark E. Smith, consumer research & public relations manager for Quantum Rehab, says the key to building power chairs that capably perform a range of functions is to view those “other” non-mobility functions not as drains on the system, but rather as valid and needed.

“It’s vital,” Smith says, “to design today’s complex rehab power chairs as cohesive systems — from the power base to the power seating to other features — so that batteries aren’t merely viewed as delivering driving range, but truly powering all of the inter-related complex rehab technology (CRT). In this way, motors, power seating systems, electronics and accessories are all optimized to run as efficiently as possible. Through optimizing all component efficiencies, the draw on the batteries is kept to a minimum, and the entire ‘system’ then meets life-sustaining mobility-related needs with little to no compromises.”

Designing for “Less Is More”

One of the challenges that manufacturers and engineers face when equipping power chairs to perform expanded duties is doing so within a finite footprint.

After all, power chairs that provide positioning, respiratory, communications and electronics support must still be able to fit through standard doorways, make turns with reasonable ease, and fit into wheelchair-accessible private and commercial motor vehicles.

Asked how his engineers balance accessibility with the many functions a power chair must be able to perform, Travers explains, “Everything is built around the size of batteries used on specific models, and each has motors, suspensions and electronics that need to be incorporated into the mix.”

“We always keep accessibility in mind when designing a new product,” Kwarciak says. “The need for additional power cannot come at the cost of wheelchair accessibility. Therefore, we look to design new chargers and power options that fit within the dimensions of our chairs. This involves designing compact power systems in addition to reducing the size of existing components to provide the necessary space. Size is a critical factor in wheelchair design, and one that we will not compromise. Doorways are not getting any wider, and neither are our chairs!”

Smith says there are ways to maximize a chair’s abilities while keeping its footprint as small as possible.

“Battery sizes are fixed dimensions that must be worked around in the power base engineering process,” he acknowledges. “However, intelligent design takes into account every aspect of a battery’s dimensions, where no fraction of an inch is overlooked. By positioning the batteries correctly and conforming the battery compartment as closely as possible, compactness is maximized.

“It’s important to match the right battery size to the application in the design process. In complex rehab power chairs, there are four battery sizes — 22NF, Group-34, Group-24 and Group-27 — and their use varies based on design goals. For example, if an all-around compact power base is wished, 22NF batteries are used because they’re 1" narrower than Group-24 or Group-34 batteries, so a power base can drop in overall width from, say, 25" to 24". However, if a super-low seat-to-fl oor height is wished in the design process, Group-34 batteries may be used since they’re approximately 2" lower in height than 22NF or Group-24s. Still, the whole CRT ‘system’ is considered, so no single aspect dictates which battery size is used, but many factors, such as balancing compactness with driving range with seat-to-floor height.”

Anticipating Future Needs

One of the greatest challenges for both the seating & mobility team and the power chair manufacturer is the client whose needs change.

Take for instance a client with ALS. When he’s first diagnosed, he doesn’t need a ventilator. But knowing how the disease progresses, ATPs and clinicians need to anticipate respiratory support down the line. So how should they go about choosing a suitable power chair?

“When looking toward progressing needs, clinicians and ATPs should consider a power chair’s power expansion capabilities,” Smith says. “Is there an adaptor kit to place a ventilator battery within the power base or to mount it externally? Is there a power take-off to power an aug-com device? Understanding a power chair’s expansion capabilities toward receiving additional power accessories is critical.”

Travers notes that generally speaking, “Wheelchair sizes are fairly close when different models are compared.” But when it comes to choosing a chair that can accommodate a client’s future needs, it’s a different story.

“Modularity is key, and not all chairs are built equal in this case,” he says. “There are different levels of modularity that exist, and some manufacturers handle that far better than others in terms of cost and labor required to do the job. Many countries around the world have wheelchair recycling programs, and Canada, which is closer to home, recycles a lot. So wheelchairs manufactured in Canada should be better at modularity because of recycling needs.”

Creative thinking on the part of the rehab team is also critical, Kwarciak believes. “It’s up to all of us, clinicians, ATPs and manufacturers, to consider future needs when specifying a chair for individuals with a progressive condition,” he says. “We need to be creative when selecting input devices and mounting hardware. With a few mounting brackets, we can reconfigure a hand-controlled joystick as a chin-controlled joystick. As a manufacturer, Permobil must also make it easier to support and power ventilators and communication devices. In many cases, the solutions are already available, we just need to educate ourselves and work through the details of incorporating the solution on-chair.”

Embracing the Possibilities

The increasing capabilities of power wheelchairs, Smith says, coincides with power chairs taking on new identities to their users.

“Power chairs are more integrated into users’ lives than ever before and serve as a multi-faceted ‘power source’ toward independence,” he says. “One’s power chair is no longer merely used to compensate for ambulation. It’s power seating to prevent pressure sores. It’s a mobile power source for ventilators and aug-com devices. It’s environmental controls. And it’s a power interface for independence-enhancing technologies ranging from lights to smart phones and tablets. The inspiring aspect to the power chair as an innovative ‘power system’ is that it’s dramatically changing the lives of CRT users.”

Future power chair progressions, Travers predicts, might involve a power source we’re already familiar with.

“Wheelchairs being powered by lithium ion batteries, which is the same technology we have in our cell phones,” he says. “Why? Because they are lighter, and a charge will last far longer than what they are used to right now. The challenge remains in making a battery at the right price that requires less space and a bit less weight. Everyone wants a lighter chair that goes fast, but the weight of our existing batteries helps in the stability of the wheelchair by keeping the center of gravity closer to the ground, so we can’t remove too much weight. But I didn’t say the weight needs to come from the batteries, either.

Right now, lithium batteries are too expensive to incorporate into government budgets these days, so cost is the biggest factor. I’d say that the next big advancements will come from the batteries because the technology exists.”

“Advances in consumer electronics have begun to play an increasingly larger role,” Kwarciak says. “Simple advances like new accessibility features in iOS make a big difference for users who need to control their iPhone but can only use a switch or two. It’s exciting to think about what we’ll have in a few years. Innovations like Google Glass have the ability to not only improve the efficiency with which power wheelchair users communicate and interact with technology; they also expand the accessibility to users with very limited functional ability. Our job is to incorporate this new technology as best and as quickly as we can to meet the expectations of our users.”

And if all goes as power chair engineers plan, operating tomorrow’s fully featured power chair will be as easy as operating consumer electronics.

“The next consumer-friendly power wheelchair options will likely involve longer wheelchair battery life and better integration of mobile devices,” Kwarciak says. “We want power wheelchair users to be as comfortable with their chair as they are with their cell phone, except that they won’t need to charge it as often.”

This article originally appeared in the May 2014 issue of Mobility Management.

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