A control system for deformable robot-fingertips was developed for grasping and releasing objects. Previously developed robot fingertips with high friction texture can stably grasp a paper box, a soft object under both dry and wet conditions. By injecting a lubricant (absolute ethanol) the grasped object slipped downwards without changing the position of the robot fingertips. The current controlling system using lubricant could be applied to robot tasks in a narrow space.