This paper presents a novel solution to the control problem of end-effector robust trajectory tracking for space robot. External disturbance and system uncertainties are addressed. For the considered robot operating in free-floating mode, a Chebyshev neural network is introduced to estimate system uncertainties and external disturbances. An adaptive controller is then proposed. The closed-loop system is guaranteed to be ultimately uniformly bounded. The key feature of this proposed approach is

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... hat, by choosing appropriate control gains, it can achieve any given small level ofL2gain disturbance attenuation from external disturbance to system output. The tracking performance is evaluated through a numerical example.