Automated milling path tracking and CAM-ROB integration for industrial redundant manipulators

[EN] The present paper explores the industrial capabilities of a CAM¿]ROB system implementation based on a commercial CAD/CAM system (NXTM) for an industrial robotic workcell of eight joints, committed to the rapid prototyping of 3D CAD¿]defined models. The workcell consists of a KUKATM KR15/2 manipulator assembled on a linear track and synchronized with a rotary table. A redundancy resolution scheme is developed to deal with the redundancies due to the additional joints of the robot, plus the one from the symmetry axis of the milling tool. During the path tracking, the use of these redundancies is optimized by adjusting two performance criterion vectors related to singularity avoidance and maintenance of a preferred reference posture, as secondary tasks to be done. In addition, two suitable fuzzy inference engines adjust the weight of each joint in these tasks. The developed system is validated in a real prototyping of a carving.This research is partially supported by research project DPI2009-14744-C03-01 of the Spanish Government, project PROMETEO 2009/063 of Generalitat Valenciana, and research projects PAID-05-11-2640 and PAID-00-12-SP20120159 of the Universitat Politecnica de Valencia.Gracia Calandin, LI.; Andres De La Esperanza, FJ.; Gracia Calandin, CP. (2012). Automated milling path tracking and CAM-ROB integration for industrial redundant manipulators. International Journal of Advanced Robotic Systems. 9(62):1-8. doi:10.5772/51101S18962Andres, J., Gracia, L., & Tornero, J. (2011). Calibration and control of a redundant robotic workcell for milling tasks. International Journal of Computer Integrated Manufacturing, 24(6), 561-573. doi:10.1080/0951192x.2011.566284Asif, U., & Iqbal, J. (2012). On the Improvement of Multi-Legged Locomotion over Difficult Terrains Using a Balance Stabilization Method. International Journal of Advanced Robotic Systems, 9(1), 1. doi:10.5772/7789Angeles, J. (Ed.). (2003). Fundamentals of Robotic Mechanical Systems: Theory, Methods, and Algorithms. Mechanical Engineering Series. doi:10.1007/b97597Huo, L., & Baron, L. (2008). The joint‐limits and singularity avoidance in robotic welding. Industrial Robot: An International Journal, 35(5), 456-464. doi:10.1108/01439910810893626Andres, J., Gracia, L., & Tornero, J. (2012). Implementation and testing of a CAM postprocessor for an industrial redundant workcell with evaluation of several fuzzified Redundancy Resolution Schemes. Robotics and Computer-Integrated Manufacturing, 28(2), 265-274. doi:10.1016/j.rcim.2011.09.008Gracia, L., Andres, J., & Tornero, J. (2009). Trajectory tracking with a 6R serial industrial robot with ordinary and non-ordinary singularities. International Journal of Control, Automation and Systems, 7(1), 85-96. doi:10.1007/s12555-009-0111-1Zhou, H., Cao, Y., Li, B., Wu, M., Yu, J., & Chen, H. (2012). Position-Singularity Analysis of a Class of the 3/6-Gough-Stewart Manipulators Based on Singularity-Equivalent-Mechanism. International Journal of Advanced Robotic Systems, 9(1), 9. doi:10.5772/4566

Calibration and Control of a Redundant Robotic Workcell for Milling Tasks

This article deals with the tuning of a complex robotic workcell of eight joints devoted to milling tasks. It consists of a KUKA (TM) manipulator mounted on a linear track and synchronised with a rotary table. Prior to any machining, the additional joints require an in situ calibration in an industrial environment. For this purpose, a novel planar calibration method is developed to estimate the external joint configuration parameters by means of a laser displacement sensor and avoiding direct contact with the pattern. Moreover, a redundancy resolution scheme on the joint rate level is integrated within a computer aided manufacturing system for the complete control of the workcell during the path tracking of a milling task. Finally, the whole system is tested in the prototyping of an orographic model.Andres De La Esperanza, FJ.; Gracia Calandin, LI.; Tornero Montserrat, J. (2011). Calibration and Control of a Redundant Robotic Workcell for Milling Tasks. International Journal of Computer Integrated Manufacturing. 24(6):561-573. doi:10.1080/0951192X.2011.566284S56157324

The exploitation of low-head hydropower by pressure interchange with air, using siphons.

The paper describes and analyses a hydropower system based on siphons in which the pressure of low-head water is converted into air pressure. The analysis suggests that, with careful design of the flow passages to minimize losses, air-pumping efficiencies of 70 per cent or more should be achievable; the overall efficiency of the hydropower system should be better than 60 per cent. Although such values of efficiency are lower than usually found in hydro plant, the economics of the system are likely to be attractive owing to the low capital cost of the system compared with conventional water turbine systems. It is shown that a siphon plant is suitable, in single-stage from, for heads up to about 1.7m. For higher heads the system can be used in two or more stages