A robotic suit developed by a wheelchair-bound Israeli engineer could soon be helping disabled people to sit down, stand up, walk about, and even climb stairs.
Taking his inspiration from the robotic exoskeletons being developed to help military personnel carry immense weights, the inventor of the so-called ReWalk system, Dr Amit Goffer, explained that the suit is not simply a hi-tech replacement for the wheelchair but has been developed to address the huge list of day-to-day problems faced by people with lower limb disabilities.
Goffer hopes the system, undergoing clinical trials at the Sheba medical centre in Tel Hashomer, Tel Aviv, will enable users to move more freely about their own homes, improve their physical health by standing more frequently, and enjoy the dignity of eye-level communication with others.
Strapped to the user’s waist and legs, ReWalk consists of four servomotors located at the hip and knee joints. These power gears and levers which in turn drive additional motors — dubbed cybermuscles — that bend the joint and feed back information on the angle it moves through. Each servomotor is controlled by an individual processor which, in turn, is governed by a small central computer that is carried along with rechargeable batteries in a backpack.
Goffer explained that the wearer initiates movement by leaning in the direction he or she wants to travel. This action is detected by a tip sensor which triggers ReWalk to take a step, sit or stand up as required. The current device weighs 14kg (30lbs), and with no integral balancing mechanism, most users would be expected to augment the system with crutches. But Goffer claims it is exceptionally easy to use.
‘Like learning to drive a car, once someone learns how to use ReWalk, he or she no longer has to think about it,’ said Goffer. ‘It’s not really a robotic device — it’s semi robotic because the user is involved in the process. If he or she is walking along and stops, the ReWalk gait stops, stands, then shifts to idle mode. If the user tilts forward again, nothing will happen until the walk mode is manually initiated again.’
As well as walking on the level, ReWalk can move the user from recline to sitting, sitting to standing, and can cope with upward and downward slopes. On stairs, they can ascend or descend with either a hand on the banister or with help, depending on their level of ability.
‘In my opinion, the hardest part is moving from sitting to standing, which the device carries out very well with the aid of crutches for balance,’ said Goffer.
After creating the initial designs, Goffer was awarded sponsorship through the Israeli government’s Chief Scientist fund, which is dedicated to small entrepreneurial technology initiatives. This resulted in the initial model and a proof of concept, which included a study of the battery needed to power it and an examination of the potential market.
Taga was then brought in to produce ReWalk’s industrial design. ‘We produced a simulation of a man and experimented with changing the angles in his limbs,’ said Jeffrey Meyer, Taga’s vice-president of engineering. ‘We did some kinematics work with the preliminary design, then went into the detailed design using SolidWorks to analyse forces and the strength of the device.’
There followed a two-year study at the Technion — The Israel Institute of Technology — which ended this February, resulting in an industrial design. The commercial model is now in development.
At the Sheba medical centre, where the clinical trials are taking place, there is a neurological and rehabilitation unit. Further trials will take place under Prof Alberto Esquenazi at the MossRehab hospital in Philadelphia, US, to satisfy regulatory requirements.
Goffer said that based on experience to date, depending on the user’s ability, it would take up to around three weeks to learn to walk using ReWalk. ‘When he or she takes it home, after a couple of months the user will really have mastered it and will come back and teach us how to use it,’ he said.
He said ReWalk would also bring huge improvements in medical conditions of those confined to wheelchairs, which would pass on savings to the healthcare system. Extensive studies were carried out on the medical benefits of another device, RGO, or reciprocating gait orthosis, which allows users to stand upright.
A passive device, the RGO allows users to stand upright or walk with locked knees. Although mainly used for physiotherapy and not very practical, time spent in a vertical stance and moving around has proven beneficial for users confined to a wheelchair.
‘It stimulates the cardiovascular system, improves cholesterol levels and helps prevent infections and pressure wounds, which alone cost millions a year in treatment and rehospitalisation expenses,’ said Goffer.
ReWalk could also save a great deal of money by replacing a variety of home help technology wheelchair users need to retain a degree of independence. ‘You wouldn’t need, like I do, a device that allows you to stand. It’s called Easy Stand — a lifting device, and a crawler for stairs,’ said Goffer.
‘The paraplegic or quadraplegic person in a wheelchair has to stand at least an hour a day if they want to stay healthy. When I go home, Easy Stand lifts me from my wheelchair to the standing equipment, where I stand for an hour or two, read, sleep, watch TV and work on a laptop — and I’m not the only one.’
Argo hopes to pilot production at the end of next year, deploying a worldwide sales network. The company is also seeking funding to continue its work. Although Goffer was unwilling to comment on the price of the system, he did say that it is likely to cost considerably less than Dean Kamen’s stair-climbing wheelchair the iBot, which costs around $25,000 (£13,000).
Future plans include ongoing improvements to the ReWalk. ‘The version you see now is going to be commercialised,’ said Goffer. ‘As with cars we will go on to produce further generations of it. We also have other ideas in the field of walk assistance for rehabilitation we will go on to develop.
‘But the biggest benefit of the ReWalk in my opinion is dignity,’ said Goffer. ‘As an adult, you are the height of a child in a wheelchair. I cannot say how important it is for someone’s psychological health to move from the status of a wheelchair user to that of crutch user, and deal with others at eye level.’
‘My main motivation is to make a difference to people’s lives. I don’t want another assisting device, I want something complete to replace the wheelchair.’