AltRocketeer

I\'ve been working on a basic closed-loop controller, using the quaternions as states and applying a full state feedback. I\'ve also read some papers (which I cannot link to here, you\'ll need a subscription to various journals) about the subject. The basics are easy to understand: you measure the position (quaternions obviously), calculate the error, derive the required angular velocity, use that in a feedback controller to actually try to achieve that angular velocity (using the angular velocities around the principle axis as states and use those in feedback). In short: you need two feedback controllers. Above is theoretical. I have no idea yet if one is able to measure the moments of inertia around the center of mass in KSP. If you want a high performance controller, you\'ll probably need a good model of the flight dynamics. I\'m currently working on the identification of flight dynamics, and the (hopefully) low complexity of the physics engine used should yield a pretty accurate model. Anyway, I\'ve actually implemented a very basic controller, which currently is lacking the angular velocity feedback loop (that\'s where flight dynamics come in). The controller currently assumes the vessel is able to achieve the required angular velocity instantaneously. I did calculate the error a bit differently, and I don\'t have an axis of freedom, just the shortest path. But that\'s how I defined performance in this case. I did analyse the controller in Matlab and turns out it performs pretty well (just need to get a better settling time, but that is just tuning).