An Approach to Specify and Test the Control Algorithm in Focus Framework

Complex embedded real time systems used in autonomous guided automotive and aerospace vehicles depend on validated control system software for meeting safety and mission critical objectives. The code implementation of these control laws presents a validation challenge due to the complexity of converting mathematical control equations, feed forward and feedback loops into validated software. This paper outlines an approach for defining specifications of a control law using focus framework. A discrete time synchronous control law consisting of gain scheduler, feedback, adder, integrator and derivative is defined in focus specifications. A methodology is presented wherein the top-level architecture is defined using composite graphical, constraint and operator styles. Sub components are specified in elementary equational and relational styles. These theoretical specifications are implemented and verified using Autofocus tool.