This study focuses on the leader-follower control problem of fractional-order multi-manipulator systems in which certain state components of the follower manipulators are unmeasurable. To address this issue, a nonlinear state observer is developed to estimate the unknown states from system outputs. The design parameters of both the observer and the leader-follower control law are then determined using the linear matrix inequality (LMI) framework. Furthermore, by applying Lyapunov stability theory, sufficient conditions ensuring leader-follower consensus are established. The effectiveness and practicality of the proposed approach are subsequently demonstrated through numerical simulations.



