Velocity-Free Attitude Consensus Tracking with Terminal Sliding Mode Observer

This paper presents a new attitude consensus tracking control law without velocity measurements by using sliding mode method. A terminal sliding mode observer is firstly constructed to estimate the velocity state of each rigid body in finite time. Then, an attitude consensus tracking control law based on sliding mode method is proposed, using the estimated states of the proposed observers. The control law can ensure attitude agreement between rigid bodies in the team and time-varying reference tracking.