This Small Business Innovation Research (SBIR) Phase II project will develop a novel, spring-based, adjustable stiffness actuator, that will power future wearable robots and exoskeletons. The actuator will be integrated into a powered prosthetic ankle which will meet the demanding requirements for lower limb mobility. Its unique ability to tune stiffness allows it to be customized to an individual, a significant impact in the wearable robotics field. It will meet the demanding design requirements that include the tradeoffs between high power need, low energy usage, compliance, robust sensing of forces, and high cycle demands. The end result is a powered ankle?]foot prosthesis that will provide near able?]bodied function to a lower leg amputee.
The broader impact/commercial potential of this project is that it will restore normal walking function to below?]the?]knee amputees. Such a device will increase symmetry and duration of walking. In fact, a below?]the?]knee amputee wearing a passive prosthetic device typically uses 20?]30% more energy to walk than an able bodied walker. Asymmetry in an amputees gait leads to joint pain, arthritis, and back pain. Because of the difficulty to walk, their conditions often lead to a more sedentary lifestyle decreasing their already limited mobility. It is documented that decreased mobility increases health risks. Elderly or overweight individuals may benefit from the technology as well. Adaptation of the technology to the powered orthosis market will expand its benefits to weak and disabled populations. In general, these groups have a more sedentary lifestyle and sometimes rely on the use of powered scooters. Because of the growing population of people with diabetes, elderly, and individuals with reduced walking ability, powered lower?]limb robots will have a significant societal impact improving health by supporting an active lifestyle.
SpringActive, Inc. specializes in providing innovative solutions to powered human assistance. Our mission is to improve the quality of life for people with mobility disorders. We have pursued this mission by utilizing more than 20 years of experience in engineering fields such as electronics, mechanics, computer science and biomechanics to develop a new generation of robotic prosthetic and orthotic devices. Being part of the original group of researchers that helped pioneer the concept of compliant actuation allows us to create optimized devices that are safe, lightweight and responsive. The focus of our NSF Phase IIB SBIR (IIP-0956828/IIP-1229943) grant is to develop a specialized version of our ROLLE robot that utilizes the addition of powered ankle to the system. Major defense contractors recognize the need for a system to provide load assistance to service men and women carrying 40-60 kg. The reason for the need to reduce soldier load can be seen in a presentation given by Dr. Marilyn Freeman, the Deputy Assistant Secretary of the Army for Research and Technology. In this presentation, she lists soldier over-burden in the top five "Big Army" problems that the Army Science and Technology communities need to address. In the past, defense contractors have attempted to reduce soldier loads by minimizing the weight of body armor, which can account for more than 27 kg of load alone (60 lbs). Only marginal savings were achieved. It is estimated that it will be likely a decade before lighter weight ballistics materials will be a viable solution to the problem, but the need is now. The goal of the Phase IIB effort is to extend the capabilities of our ROLLE device. The original system was designed around level ground walking. To assist soldiers over uneven terrain and to climb and descend significant slopes, powered actuation around the robot’s ankles is required. The design and integration of powered ankles with the existing ROLLE system was developed in the Phase IIB effort. Testing showed the the addition of addition of torque to the ankle joints significantly increased the wearers overground speed while walking on level ground, with no impact to their metabolic expenditure. Also, while walking up a 10 degree slope a metabolic savings of 14% was achieved compared to no ankle assistance.
