INTRODUCTIONThe IDP is about working in a team to build a robot. The robot must collect fittings (which are about 10cm in size) from a collection area and measure their temperature, sorting different temperature fittings into different bins. Our entry was working well: fairly reliable and fast enough to move all five fittings in the required time, mostly because we had made a working robot quickly enough to allow plenty of time to iron out any problems. |
Day | Thur | Tue | Wed | Thur | Tue | Wed | Thur | Tue | Wed | Thur | Tue | Wed | Thur | Tue | Wed |
Week | 1 | 1 | 1 | 2 | 2 | 2 | 3 | 3 | 3 | 4 | 4 | 4 | 5 | 5 | 5 |
Mechanical Sub-team | Abstraction, delegation | Conceptual Design | Agreement upon interfaces | Function Design | Design and build chassis + drive | Assemble moving vehicle | Design and build lift and grab functions | Assemble complete robot | Go to Pub | Test complete robot, catch up |
Evaluate |
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Electrical sub-team | Function Design | Make sensors + motors functional | Build rest of circuits | ||||||||||||
Software sub-team | Function Design | Go Shopping | Test and debug navigation code | Test and debug Kenny handling code |
One of my ideas for the lifting function was to tilt the entire robot, either by accelerating very hard using the drive motors or by moving a mass, to overbalance it. The mass could be pushed backwards by a pneumatic ram, lifting the fitting. However, this idea fell apart when we worked out that we would need a 50° tilt angle to lift it over the wall of the bin before placing it there. |
The mechanical team decided to use a chassis that stayed horizontal so that the line sensors would stay close enough to the lines. They attached a moving platform that was tilted by a pneumatic ram. The arm, fixed to the moving platform, had jaws on the other end. The microprocessor was, as initially planned, mounted on the moving platform, but it turned out to be easier if the moving platform was made relatively small. On the final version, the microprocessor sits on the static frame and the moving frame is simply part of the arm. |
Device | Supply voltage | Forward Voltage | Current | Series Resistance |
Indicator LED | 5V | 1V7 | 20mA | 165R (180R) |
Infra Red LED | 5V | 1V25 | 35mA | 107R (100R) |
Phototransistor | 5V | N/A | N/A | 33k (33k) |
Action | Problems |
Get from starting area to collection bay | Occasionally goes straight on, into wall |
Lift fitting in correct part of jaw | Jaw sometimes lands on fitting |
Set off with fitting in right direction | Occasionally fails to turn around at C |
Arrive at D1 | No problems |
Arrive at D2 | No problems |
Arrive at D3 | Sometimes does 45 degree turn too early |
Get back to starting area | Occasionally turns left early and gets lost |