This paper is concerned with trajectory tracking and obstacle avoidance control using avoidance manipulability of redundant manipulators. We proposed a robot control system to deal with unknown object by combining an avoidance control system and preview control system. However, through the simulation studies, it became clear that the shape of redundant manipulator was not always kept to the best configuration on the view point of shape-changing ability. In this paper we propose a new criterion to evaluate the shape-change ability in the configuration space while tracking the hand-desired trajectory. Using this criterion we constructed real-time configuration control system with preview evaluation by imaginary manipulator in future time. Finally the proposed system was evaluated by several simulations on the point of real-time configuration, and the feasibility of total system was analyzed.