Exoskeleton development

Parker Hannifin’s Human Motion & Control business unit continues to refine the design of Indego, a powered orthotic that allows paraplegics to stand and walk.


Motion and control experts Parker Hannifin Corporation surprised many in late 2012 when officials announced the company was entering the medical device market with a powered exoskeleton designed to allow paraplegics to walk.

Since then, the company has signed a licensing agreement with the device’s developers at Vanderbilt University, hired several members of Vanderbilt’s research team, named the exoskeleton Indego, and has begun the regulatory approval processes needed to market the device in the U.S. and Europe.

Achilleas Dorotheou, vice president and head of Parker’s human motion & control business unit, recently spoke to Today’s Medical Developments about the company’s move into medical and the future of mechanically assisted human motion.

TMD: Vanderbilt had done a lot of development work when you signed your licensing agreement with them in early 2013. How different is Indego now that Parker’s been developing it for more than a year?

Dorotheou: We have built what we think is an A-team around the original co-inventor [Dr. Ryan Farris who Parker hired from Vanderbilt], and in the last 12 months we have worked to refine the academic prototype – which was already pretty robust. We demonstrated generation two to our executive team in late March 2014.

It is a very refined, polished commercial product that we will use for our clinical trials, and is the product that we expect to be commercialized.

It is now slimmer, has a more refined design, and is more powerful. Since it’s a modular design, all the quick connects have been completely optimized so the device can be snapped together blindly. Paraplegics may not actually be able to see all the connections that need to be made, but they can hear and feel them when snapped together. We now have a medical-grade laptop style battery that can snap in and out easily.

Then there is a wireless interface for physical therapy use, so the physical therapists can set the device parameters remotely for a particular patient while using it.

TMD: What can the physical therapist do with Indego’s wireless controls?

Dorotheou: The physical therapist can range from the angle with which the paraplegic can be standing versus the weight they have to hold. So they may have different angles and postures of each user. The hip may be different for one than the other. They can also set the length of the stride – not an infinite number of options, but three options to best fit each patient. In the clinical development we have infinite options that we hone to three in physical therapy.

How Indego works

Step 1: Vertical and horizontal position sensors monitor when a patient is standing still and when he is leaning forward.

Step 2: The patient leans forward, and much like a Segway scooter, the device interprets that as intent to walk.

Step 3: Indego activates motors at the knee and hip, lifting the patient’s leg. The forward momentum created by the patient’s lean propels the lifted leg, effectively taking a step. Patients use crutches for balance and to control the direction of steps.

Step 4: When the patient stops leaning forward, the device stops initiating leg lifts, returning him to a standing position.

We have different speeds depending upon the capability of the patient. The beginner patient starts slow with smaller steps, and as they develop, they increase speed and stride.

TMD: In late 2012, Parker officials said they expected the exoskeleton on the market by 2014. When do you expect it to be commercially available?

Dorotheou: Part of the reason we selected this device is that it has the most real, or current, technology commercially feasible over the next year for Europe and quickly after in the U.S.

Rehab is the first market we are entering. Clinics come first for spinal cord injury rehab, and then potentially rehab for stroke and other neurological diseases, but first the FDA needs us to research how it is used in a clinical environment with supervision, such as physical therapy. After experience in the clinic environment, it may be used in the home without supervision and then for general community use. That’s the commercialization path, but it doesn’t change much in design for each use, it’s just how it’s approved.

TMD: What goes into each Indego?

Dorotheou: We have a number of chips calculating the posture of the user 500 times a second. The system will go through eight different states of getting up just to make sure the person is balanced. The calculations are a myriad of technologies to determine position, speeds, and angles.

It’s actually a very rich, highly instrumented device that has chips that combine inertia measurement units with gyroscopes and other microprocessors.

Roughly 85 parts make up the system, and we use both internal and external sources. We have many of our own technologies and vendors from outside. It’s a merging of systems and parts.

TMD: Indego uses positioning sensors to determine when a user wants to walk and where he wants to go. Other companies have recently demonstrated devices that can be controlled by the user’s thoughts. Do you have any plans to develop similar controls?

Dorotheou: You see mind control and experiments, etc., in the press. They are just experiments. In our view they are not ready yet for commercialization in the immediate future.

For mind control, you might be able to see how much can be controlled – maybe two or three states – but that’s not enough to give guidance to a device for what the patient’s intent is.

TMD: What does the development map for Indego look like?

Dorotheou: In the near future we hope to introduce functional electrical stimulation. We have partnered with those clinical settings that are really interested in this functionality and working on this already. We lined up a few pretty big names to work on the integration of the mobility function with electrical stimulation.

Then in the following year we plan to introduce the variable assist or follow mode. This would allow Indego to work with the stroke population and broaden the range of people that can benefit from this device.

[Editor’s note: Variable assist refers to walking modes for patients with differing levels of impairment. While Indego was designed for paraplegics with no below-the-waist muscle control, people who can control most or all of one leg would need variable levels of assistance to achieve a normal gait.]

Indego advantages

Ekso Bionics and ReWalk have exoskeletons on the market or in development, but Parker says Indego has several unique features.

Lightweight: At just 27 lb, Indego is portable, making it easier to transport and carry around in a wheelchair before use.

Individual use: Its compact, lightweight construction allows patients to don the device while sitting in their wheelchairs.

Modular design: Indego can be put on and taken off quickly with no-look connections, and turn-to-fit strapping allowing for maximized therapy time.

Manage parameters: Indego’s software app allows you to control gait training parameters such as stride length and pace, and record performance data.

TMD: The Human Motion & Control Division is new for Parker Hannifin. When did you get started?

Dorotheou: The project began before the unit was established – before the formal business unit began with a monetary value and formal organization. The whole motion and control strategy began three years earlier as a mission set by Parker’s CEO [Donald E. Washkewicz] that was a small team looking at these technologies and evaluating what Parker’s role could be in human motion and control.

The exoskeleton came about and it was the right product at the right time for this unit. It reflected a lot of Parker’s pedigree with automation, controls, and motion. We felt that Parker could have a role in capitalizing and really playing a leadership role in transforming this industry.

Indego is the first step to building our larger platform strategy for Human Motion & Control. We include all kinds of advanced, powered, connected, and intelligent devices that are either for prosthetics, orthotics, or neurorehabilitation technologies. We are already gaining traction with Indego, but we are also evaluating other devices to bring on board to the platform. We have established some collaborations with other technology companies in this space.

TMD: How does Parker expect to stay competitive in medical devices and human motion?

Dorotheou: Since we are a large company, we have the resources to be mapping the field for the latest technologies out there. There’s always new energy entering the field. Some of those players in the prosthetics and orthotics market truly believe that the time has come for the exoskeletons to be a true product.

I don’t think the evolution will stop. Being a larger company, we have a lot of smaller companies coming to us and presenting their innovations, so I think we will have first pick when technologies are available.


Indego / Parker Hannifin


About the author: Robert Schoenberger is an editor of TMD and can be reached at rschoenberger@gie.net or 330.523.5381.