Energy Efficient Satellite Attitude Control through Direct Commanding of Reaction Wheels Speed

A new approach for attitude control of satellites actuated with reaction wheels is proposed. The method is based on directly commanding the speeds of reaction wheels; the output of the controller is a direct speed command to the reaction wheels instead of a torque command or its equivalent speed increment command. Another novelty is the account of the actuator dynamics in the controller design, which is usually neglected in the commanded torque control. A second order model of the actuator dynamics that explicitly depends on physical parameters of the motor and flywheel is presented. A PID controller is adopted and a multi-objective optimization and criteria for tuning the controller are proposed. The proposed criteria lead to an optimal balance between the transient response and energy consumption of the system. It is shown via simulations that the proposed multi-objective optimization surpasses the single integral performance criterion based optimization.