Sliding Mode Control of a Vision Augmented 3 DoF Quadrotor with Input and State Constraints

This work presents the development of a sliding mode controller (SMC) for a 3 DoF vision augmented quadrotor which subjected to input and state constraints, in the presence of system uncertainties and bounded external disturbances. The approach relies on using a modified constant plus power rate reaching law that will ensure to keep the rate of change of the sliding variable bounded, irrespective of the initial conditions of the system. The paper also derives the relationship between the state and the input constraints and the controller gains, hence allowing the user to assign suitable values for the same based on the imposed constraints. Such a design plays a vital role in visual servoing as it helps maintain a smooth tracking profile while ensuring minimum stress on the actuators. To demonstrate the efficacy of the proposed controller over the vision augmented model, numerical simulations are presented and the findings are compared with an existing state of the art sliding mode strategy.