Abstract: When spacecraft perform high dynamic agile maneuver or attitude dynamic tracking control tasks,the hybrid actuator composed of control moment gyroscope (CMG) and reaction wheel (RW) was often used to provide control torque.A control law of hybrid actuator based on the optimization of torque output capability was proposed.From the geometric point of view,the angular velocity and RW angular acceleration of CMG frame with the optimal torque output capability were given.By introducing the parameter,the mixed quadratic form of frame speed error and output torque error was minimized,and the output torque error of the hybrid actuator was minimized under the condition of optimal torque output capacity.Taking the hybrid actuator composed of pyramidal CMG cluster and orthogonal RW cluster as an example,the control law of hybrid actuator based on the optimization of torque output capacity was rationalized,the effect of introducing parameter was proved,and it was proved that there was no CMG singularity in hybrid actuator.The simulation results show that the hybrid actuator control law based on the optimization of torque output capability solves the problem of CMG singularity and makes RW not fall into saturation,and the output torque error is small.

Key words: control moment gyroscopes(CMG), reaction wheel(RW), optimal output torque capability, steering laws, mixed quadratic form