We took the unassembled Tina Treks to the school during half term, we had the use of the playground to test her for one day, so we spent the morning assembling her in the playground, and began our tests at lunchtime. It started badly and continued as a comedy of errors for the rest of the day.
Initially she would not walk and it was very difficult to set the walking parameters to get her to walk. The three feet on the ground at a time strategy did not work at all well, we did manage to to get her to walk for about 20 seconds with the two feet on the ground strategy, but we had no control on the steering, and she was greatly affected by the gentle slope on the playground, we had to stop this test as one of the tie bars holding the lower chassis on, became unscrewed. This marks the beginning of it all going downhill!
These initial tests showed that the suspension which keeps the legs from collapsing under the body was too soft and she looked like a foal or giraffe learning to walk. We then did a few more test, each one would last no more than a couple of seconds before, another tie bar would drop off or we would run out of petrol. Then in one of the tests the legs on one side collapsed under the body and she fell on her side. One of the suspension parts had crumpled and the legs moved under the body. We took the offending part off and straightened it with a hammer it is a piece of Aluminium about 50cm long 5 cm wide and 3mm thick. We put it back on and modified the system so that the legs would be held in a more spread eagled position.
We then did a whole series of test not lasting more than about 10 seconds each, due to bits falling off or running out of petrol. Finally the walking sequence stopped working. We eventually traced this to the transmitter batteries being flat. So we replaced them. The walking sequence continued to work for a few more short, failed tests, when it stopped working again. By now it was about four o'clock and we were getting tired and depressed. The walking sequence stopped on this occasion because a sensor which is held in with hot glue had become loose.
Okay, it was time to call it a day. We needed to use the legs as jacks to sit her feet on some small blocks of wood, so that she could be sat on her trolley ready for dismantling. This was not to be, as one of the legs broke at the hip during this process, with the hydraulic ram popping out the side of the leg bending the rod of the ram and her falling heavily on her side. Oh..........?????
Then spent the next two hours slowly dismantling the pile of wreckage and packed it away in the trailer. What a depressing time....
After speaking to the Techno games office we decided to make the legs shorter, their maximum length will now be no more than two metres. With the help of Stuart we managed to salvage the legs at two metres, and using a long length of steel water barrel to straightened the bent hydraulic ram,. By the end of Friday we had the legs shortened the frame strengthened (It was banana shaped by the end of Tuesday), had stiffened the suspension, fixed the hydraulic ram into the leg more securely, and managed to do a very short test. She walked, still only the two feet on the ground but it looked really quite good.
We took Saturday quite slowly, in the morning organising another test in the school car park. This time we took her fully assembled. (The legs overhung the edges of the trailer by about 30cm!) Anyway, by late afternoon we did some more testing, yes she was walking and quite well, she was affected by the slope of the car park but with careful setting of the walking parameters she would walk in the direction required.
Time to push it a bit, we then ran the engine at full throttle, oh yes she was going now, but not for long..... another leg broke, it had broken at the hip, and on inspection of the other legs they were all fracturing in the same place.
Time to be depressed again, so we packed her away, came home and took all the legs off. The same ram as before had got bent! Phoned the Techno games office again... and then spent the rest of the evening dismantling the legs. This time we could not simply make them shorter and had to start afresh rebuilding them. By the end of Monday we had all four legs rebuilt, modified to reduce the likelihood of the same failure, and fitted back onto "Tina Treks", there was no more time to do any testing, so this was it!
We spent the morning sorting out tools and spares to take to the competition, while waiting for the ordered lorry to come and pick up "Tina Treks", yes that is right a lorry, she weighs 200kgms, is 2m long 1.5m wide and 2m tall.
A lorry did not turn up, a transit van came instead. I don't think she going to fit in there, and eventually it was agreed that the van would be sent away. There was then a frantic hour sorting out an alternative lorry/van. By six o'clock Tina Treks was loaded in a big van, and by eight o'clock she was unloaded at the Millennium Dome. Back home again and straight to bed for an early rise to take the team to the Dome for 0830 Wednesday.