Compliance and mind games

Citation

Loughlin, C. (2007), "Compliance and mind games", Assembly Automation, Vol. 27 No. 3. https://doi.org/10.1108/aa.2007.03327caa.001

Compliance and mind games

The idea of using robots for automated assembly has been around almost as long as robots themselves. In some niche areas such as printed circuit board assembly they have been a great success, although they are often called “pick-and-place machines” rather than “robots” (if it waddles like a duck and quacks like a duck, then it is a duck). However, in most other assembly operations robots are yet to get a serious look-in. This is partly because of the availability of low cost labour in developing countries, and partly because people are very good at it.

The main reason that people are very good at assembly is because our hands make very adaptable grippers and our eyes and sense of touch provide us with real time feedback that allows us to compensate for component alignment inaccuracies and the worse than 0.1mm absolute accuracy of our arms. All these factors give people a big advantage, however, I believe that their importance is dwarfed by the other major feature of human arms which is their natural compliance.

Very few robots are naturally compliant. Pneumatic manipulators had a lot going for them but they have been dogged by problems of control that limited them to low accuracy and low speed applications – at least as far as robots are concerned. Other groups have tried incorporating force sensors within the joints of robots or six axes torque sensors mounted just behind the end-effector and these have had some success, but they always strike me as being “get-arounds” rather than optimum design solutions.

Fortunately arms such as the WAM by Barrett Technology and the DLR Light Weight Robot are providing fresh leadership in this area and it will be very interesting to see how they get on in automated assembly operations.

For many companies the solution to low cost assembly is simply to subcontract their assembly operations to developing countries where labour is cheap but also where there is a mind-set that is determined to succeed. Have we in the “developed” world actually just become lazy? Is a solution that entails simply giving your problem to someone else to solve really a solution at all?

Sudoku is currently a popular entertainment in many countries. Those that do it challenge themselves to solve problems of varying difficulty and in the process become better at it and hopefully better at problem solving in general. If instead of tackling the puzzle yourself you asked a friend to do it for you then several things happen. First your friend gets better at doing it and is therefore better equipped to help you in the future, also the friend gets the pleasure of the challenge and its successful conclusion. But what do you get? If you pretend to others that you have done it yourself then you may get short term glory but you are ultimately just cheating yourself; and if you own up then other people will know not to ask you for help in the future but instead to ask your friend.

Clive Loughlin