RuBot II

This is RuBot II – The Rubik’s Cube solving robot. Yes, it really does solve Rubik’s cubes.

It's very different to the prototype but it has to be the coolest looking robot solver ever. There are cameras in the eyes of the head that scan the cube before the pneumatic arms solve it. It usually solves the Cube in about 35 seconds (not including the scan) no matter how much it is mixed up.

The solving algorithm is taken care of by Herbert Kociemba's Cube Explorer software and usually solves the cube in a maximum of about 20 moves. In this video, the cube wasn't mixed up too hard so RuBot was able to find the optimum solution.

RuBot picks up the cube cube and proceeds to scan all six sides with its colour vision.

The webcams that are used in the eyes for scanning the cube are probably the weakest link in the system. They are very sensitive to light and colour changes. Light that is too dark or too bright washes out the colours.

Once all six sides are scanned, RuBot works out what moves it needs to make to solve the cube using Herbert Kociemba's Cube Explorer software. The solution is usually less than 20 moves. It is important to keep the number of turns as low as possible because RuBot only has two hands and must swap from hand to hand to make turns. This slows down the solve.

RuBot can cope with a few errors. If a cubie is twisted to make an incomplete cube, then the solver will usually still solve the cube except for the twisted cubie. RuBot's arms can jiggle out of alignment and need to be recalibrated occasionally or RuBot will end up dismantling the cube. However, RuBot can cope with slight misalignments at slower speeds so RuBot's speed is reduced for reliability. With near perfect calibration, RuBot's speed can be increased by about 20%.

The other main factor affecting solve speed is the condition of the cube. If the cube is too loose, then the momentum of each turn causes the cube side to continue the turn. This misaligns the sides and RuBot eventually breaks the cube up. Similarly, if the the cube is too tight, the sides can stick and again misalign.

Here is another clip of RuBot in action. This time the cube is mixed up pretty good. You can cleary see the three steps. Step 1: Scan the cube. Step 2: Work out the solution. Step 3: Carry out the solution.

I am still working on the site so I apologise if anything is not working during construction.
I will endeavor to get it up as quickly as possible.