Discrete Multiobjective Optimization Methodology applied to the Mixed Actuators Problem and Tested in a Hardware-in-the-loop Rendevzous Simulator

The spacecraft control problem using a set of actuators with conflicting characteristics is investigated in this paper. A novel approach, called actuator multiobjective command method, based on a discrete multiobjective optimization technique is proposed. The method is included in a coupled translational and attitude control system applied to the final approach rendezvous. Furthermore, all elements of the guidance, navigation and control loop have been developed and implemented in a simulation framework. A reaction control system, a set of reaction wheels, and a set of magnetic torqrods are the group of actuators used in this work. The discrete multiobjective problem is formulated with four objectives: torque error, fuel and electrical charge consumption, disturbance of coupling, and risk of utilization. The decision variable represent the command torque to the actuators. In addition, the hardware-in-the-loop rendezvous and docking simulation facility of the German Aerospace Center has been used to test the proposed method under realtime conditions. Results indicate that a mixed actuators methodology can achieve better performance with respect to those using the same type of actuators.