Hard Real-Time Control of an Inverted Pendulum using RTLinux/Free

Abstract: The content of this master thesis regards the implementation of a control system in RTLinux/Free, and the use of this for control of a straight track inverted pendulum. A controller developed on the hypothesis that the system is sampled with the sampling time ts will perform differently than expected if sampled with the sampling time t _= ts. If implemented in a regular operating system, the computer will fail to meet demands of hard real-time sampling constraints, i.e. that the desired sampling time must be the one used by the system at all times and in all situations. A computer controlled system in this environment will thus perform di.erently than expected most of the time. Often 'di.erently' is the same as various degrees of worse. The underlying objectives for this project was the desire to be able to control and do research on a hard realtime system connected to an unstable non-linear plant the inverted pendulum. This master thesis covers the work of creating a hard real-time platform using RTLinux/Free on which to add control features. It deals with communication betweenhard real-time and soft real-time, kernel module programming, modelling, linear state feedback, linearization, energy functions, friction compensation, etc.