Home robots - not a leg to stand on?

Citation

Loughlin, C. (2003), "Home robots - not a leg to stand on?", Industrial Robot, Vol. 30 No. 6. https://doi.org/10.1108/ir.2003.04930faa.001

Home robots - not a leg to stand on?

Home robots - not a leg to stand on?

I was honoured and very fortunate to be asked to chair the modestly titled "Great Debate" at the 34th International Symposium on Robotics in Rosemont, Illinois in June 2003. Our very distinguished panel comprised Joe Engelberger, Professor Rolf D. Schraft (Director of Fraunhofer IPA, Germany), Professor Henrik I. Christensen (Centre for Autonomous Systems, Royal Institute of Technology, Sweden), Professor Zenn Bien (Director of Human-Friendly Welfare Robot System Research Center, KIST, Korea) and Colin Angle (CEO of iRobot Inc.).

The aim of the session was to debate the future development of service robots for the home. It would be difficult to find another five people better qualified to discuss this topic, or who would be likely to have such a variety of different opinions. One area on which everyone seemed to agree however, was the method by which the robots should move around. Everyone went for wheels or tracked motion.

As moderator I needed to bite my tongue, but changing to my editorial hat, I would now like to say why I think all these experts are wrong.

First, I should perhaps state that if I was to be given US$ 5 million to develop a useful caregiving service robot for the home environment, and within shortish timescales, that I would probably go for wheels as well. However, if we leave small matters like finance to one side and allow 3-4 years for its development I would go for legs every time.

Wheels do have a lot going for them. The experts will cite the classic engineering benefits of keeping the weight low down, of low energy requirements and the fact that it takes no energy just to stay put. My objections to wheels and tracks are that I do not see them working that well in a home environment.

One application for the robot is to act as a helping hand for the elderly or infirm person. It needs to be able to negotiate its way ahead of them into various rooms of the house, including the bathroom. It also needs to be helpful if the person actually falls over. The idea of the helping hand is that it helps prevent the person from falling, but what if despite its best efforts the person still falls and takes the robot with it? The wheel based robots relies on a high mass in its base to help it lend the helping hand and support the person. If the person pushes or pulls the robot over then the consequences are likely to be serious. Certainly much worse than would be the case with a human helper.

A legged robot relies on dynamic rather than static stability to keep it upright. This same skill would enable it to brace itself against the falling person and (with luck) stop the fall happening in the first place. Also the legged robot would need to be strong, but it would not need to be heavy, so the worst case scenario is still an improvement.

Wheels are meant to be highly efficient and having the weight low down certainly makes sense, but I am always left asking - "How come people climb mountains with heavy packs on their backs and only a Snicker bar in their bellies?"

Current examples of legged motion such as the Honda Humanoid may be inefficient, but I believe that this is only because we do not yet know how to walk correctly and efficiently. However, ongoing research into legged motion and in particular, pendulum mechanisms does look very interesting. In my view only two things are stopping robots from walking as well and as efficiently as people and those are the basic methods used and the actuators. At then moment we are doing it the wrong way and using the wrong actuators.

What about getting around a house with stairs? My home is quite modest, but it is split over five levels, and that is just inside the house, never mind going outside. Solutions

offered include designing the house for the robot. Nice idea, but one of the principle raison d'être for home robots is that it enables people to stay in their own homes.

The NASA Robonaut was designed specifically so that it could work with the same equipment and in the same environment as people because that is what it would have to do.

Tracks or fancy wheels are options, but they all sound rather unattractive, cumbersome and expensive to me. Sometimes people mention ramps - these would be OK for small steps but not flights of stairs. Other offerings are to have robots on each level but this obviously increases costs, and besides, cleaning the stair carpet is probably a good task for the robot.

These are just a few of the reasons that I favour legs. The jury is still out, but I would back C3PO over R2D2 any day.

Clive Loughlin

Call for papers

IR 31:1 - Welding + Cutting + GrindingCopy deadline: 6 September 2003Recent developments and applications using robots for welding, cutting and grinding.

IR 31:2 - Machine Vision + CLAWAR ConferenceCopy deadline: 24 October 2003Machine vision and image inspection used in conjunction with robots. Also selection of papers from the 2003 CLAWAR conference.

IR 31:3 - Automotive IndustryCopy deadline: 26 December 2003Present and future applications for robots in the automotive industry.

IR 31:4 - Plastics + Electronics IndustriesCopy deadline: 15 February 2004Robot applications in the plastics and electrical/electronic industries. Concentrating on assembly operations.

IR 31:5 - Robotics in the Military and Aerospace IndustriesCopy deadline: 17 April 2004Robot applications in the military, aerospace and aircraft industries.

IR 31:6 - Medical RoboticsCopy deadline: 19 June 2004Developments and applications in the field of medical robotics, surgery and rehabilitation.