Abstract: Backstepping control scheme was an effective way to design control laws of a cascade system.Quaternion-based attitude equations of a rigid body was a typical cascade system.For the rigid-body attitude tracking control problem with influence of constant disturbance torques,the backstepping control method was used to design a quaternion-based tracking control law for a rigid body with integral terms,which were used to reduce steady-state errors caused by constant disturbance torques.Then the global stability of the control law was also achieved by adding of cross terms in Lyapunov candidate function.The control law is validated by simulations.

Key words: Integral term, Backstepping control, Attitude tracking control, Design Simulation