Robot arms have been widely used in the industry for many decades. They have played a very important role in factory automation. However, actuators failure might occur due to unfrequent maintenance or limited life cycle, which could cause severe damages to the operators and products. To solve this problem, an adaptive PD controller incorporated with a nonlinear compensation term is developed. This controller is designed based on conventional PD control scheme combined with adaptive control algorithm. Theoretical proof for the closed-loop dynamic system is given via Lyapunov theorem and La Salle’s theorem. To demonstrate the validity of the controller, a number of computer simulations as well as experiments are also performed.