Sunday, 22 April 2012

The plan was to test a new stainless light thruster yesterday but that diffident end up happening as Buren had a class and Scott was busy. The simulation is going fairly well, I now have a nice 3d model which falls under gravity and has basic roll control via PID control that can correct for misalignments in starting orientation. I have found the biggest challenge is working with the coordinate system and trying to understand if it is behaving as it should. Ariel seems to think that countering gravity should be the main task and roll control should then come in, which will stop the vehicle loosing altitude wheel translating. This involves either having an estimate for mass which is always changing, or minimising vertical acceleration. I think this is too complicated and think that roll control should come first. For manual control this is probably the case but I am not sure for automatic control.

The first task I would like the vehicle to perform is a basic hop. That will mean throttling up until it senses positive acceleration, throttling to achieve neutral acceleration while travelling up for a period of time, throttling down for negative acceleration then maintaining till it detects positive acceleration via impact with the ground. All the while the roll control will need to stabilise the vehicle.

I am still unsure weather I want to peruse manual control like Armadillo did. After I get basic hops working I suppose I will want to get translational motion working, which without a joystick will involve some positional sensors. GPS is really appropriate for the small distances the vehicle will be travelling and a range finder for height will be quite expensive. Manual input would bypassing the need for any absolute sensors.

I really need to machine up the new engine and we need to conduct a ling duration firing so we can start on the vehicle. By the time this is done the simulation should be at the point where we can see what geometries are optimal.

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