Advanced Robotics

Parnichkun, Manukid; Ozono, Shigeo

doi: 10.1163/156855398X00370pmid: N/A

Robot cooperation means 'work-accomplishment action with collaboration of multiple robots by applying shared information, transmitted from a robot to others in a system'. The definition implies that efficiency of a cooperative robot system depends directly upon two main factors, one is communication among the robots and the other is movement of the robots. Robots with appropriate cooperation are expected to work efficiently. The authors propose here an efficient communication method for a cooperative robots system, Code Division Carrier Sensing Multiple Accesses with Collision Detection (CDCSMA-CD). CDCSMA-CD, differing from communication methods in the past, is specifically designed for a cooperative robot system so it can be applied appropriately for both point-to-point and broadcast communication. Within this paper, the principle and hardware structure of the proposed CDCSMA-CD are described. The efficiency of CDCSMA-CD, compared with other communication methods, is then evaluated and discussed.

Zheng, Xin-Zhi; Ono, Kazuya; Yamakita, Masaki; Katayama, Masazumi; Ito, Koji

doi: 10.1163/156855398X00389pmid: N/A

We present a control framework for robot systems to perform dynamic manipulation tasks, with robotic batting as an example. A properly preplanned trajectory for manipulators is recognized to be important to increase the probability of success. A nominal path for a manipulator to travel in a swing motion is computed while optimizing the stochastic dynamic manipulability measure to cope with the unpredictable deviation of the ball. A nominal trajectory along the path is then planned in a minimum-time fashion for the benefit of catching the ball as accurately as possible, the behavior of which is observed visually and estimated on-line. A control structure consisting interpolatively of a path velocity controller to follow the nominal trajectory and a resolved-acceleration-natured ball-deviation compensating controller, together with a ball motion prediction, is proposed. The effectiveness of the proposed approach is examined using computer simulations. The strategy provided in this paper will be useful to make manipulators perform further task requirements better for a wide range of dynamic manipulations.

Lee, M.Y.; Sturm, A.J.; Lavalle, D.

doi: 10.1163/156855398X00398pmid: N/A

A new way for multi-axis robot trajectory planning using a single cubic spline incorporating velocity and acceleration clipping is presented. Equations for velocity and acceleration clipping employing the cubic spline function for a single axis are derived. A robot tool-tip velocity vector magnitude clipping algorithm is proposed. Implementation for a fly-by and contour following trajectory control is discussed.

Ueno, Naohiro; Kaneko, Makoto

doi: 10.1163/156855398X00406pmid: N/A

This paper proposes the Self-excited Dynamic Active Antenna (SDAA) that can detect a contact location between an insensitive flexible beam and an object through observation of the fundamental frequency of the beam in contact with the object. The main part of the SDAA is composed of a flexible beam, one permanent magnet and two electromagnets. The permanent magnet is attached to a part of the beam and two electromagnets are positioned at both sides of the permanent magnet with a small gap. These magnets not only contribute to exciting the motion but also changing the boundary condition of the beam. We analyze the relationship between the displacement of the permanent magnet and the induced force, and show the linear spring-like behavior of the magnetic force. We also show that the contact position is uniquely determined by utilizing two fundamental natural frequencies before and after changing the boundary condition, whereas both the fundamental and the second natural frequencies are required for localizing the contact point under the conventional type of Dynamic Active Antenna. We present the basic working principle of the SDAA and show some experimental results to verify the idea.