This paper presents a novel visual tracking model in image plane for autonomous mobile robots. Based on this control model, a single visual tracking controller is proposed for both static and moving objects in a two-dimensional plane. In this design, the mobile robot is equipped with a fixed camera for environment detection. The visual feedback is used to control the robot pose for tracking a moving object of interest. A novel state space representation of the camera-object visual interaction model fully defined in the image plane is first derived, a closed-loop stabilizing control law is then designed. The visual tracking control scheme achieves exponential convergence of the closed-loop visual tracking system through pole-placement method. Simulation results verify the effectiveness of the proposed control scheme, both in terms of tracking performance and system convergence.