This paper presents a new algorithm for object handling tasks based on active tactile and slippage sensations using a humanoid robot multifingered arm for an object that exists at an arbitrary position. The idea is to enhance real-time object handling tasks based on tactile sensing in humanoid robotics, where grasp, move and release motions are involved. We developed a novel hemisphere-shaped optical three-axis tactile sensor to mount on fingertips of the robot arm. The tactile sensor is capable of defining normal and shearing forces simultaneously. For grasp and release motions, we designed the algorithm based on slippage direction analysis consisting of coordinate transformation of the sensing element for the arm global coordinate. The robot control system uses the analysis results to determine whether an object is in contact with the ground without needing to measure the height of the ground. The algorithm was evaluated in experiments with soft and hard objects, whereby results revealed good performance for the robot fingers in handling an object at an arbitrary position.

This paper present object handling capabilities of two robotic hands equipped with optical three-axis tactile sensor. We present optimization of grasp control in tactile sensor and robot hand control system to precisely control robot hand based on tactile sensing information. To enhance performance of the robot hand, stiffness distinction parameters were applied in the control system. These parameters are used to select velocity ratio of robot hand to control re-push motion and define optimum grasp pressure. In addition, slippage recognition method is also applied so that the robot hand can grasp and handle object located at arbitrary position. The proposed control system and parameters were evaluated in object handling experiments with hard and soft objects, and object located at arbitrary position. Experimental results revealed good performance for the robot hand in handling hard and soft objects, and object located at an arbitrary position.