Online velocity planner for Laser Guided Vehicles subject to safety constraints

Laser Guided Vehicles (LGV) are largely used in industrial contexts for the autonomous dispatching of huge loads. LGVs of automated warehouses are driven by supervisory systems which assign their tasks depending on the process demands. The vehicle workspace is partially structured and it is normally shared with several independent agents like other LGVs, or human operated forklifts, or humans which directly interact with the vehicle itself. For efficiency and for safety reasons, LGVs move along pre-defined paths so that, if an unexpected obstacle is detected, they must be promptly stopped so as to avoid impacts. As shown in the paper, the safety problem is normally handled by limiting the plant productivity. This is clearly an improper approach, which can be overcome by considering a novel velocity planning strategy. The one proposed in this paper guarantees high safety standards, thus preserving the physical integrity of human coworkers, by simultaneously improving the plant productivity.

[1]  Helge J. Ritter,et al.  On-line planning of time-optimal, jerk-limited trajectories , 2008, 2008 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[2]  Paolo Fiorini,et al.  Motion Planning in Dynamic Environments Using Velocity Obstacles , 1998, Int. J. Robotics Res..

[3]  Dinesh Manocha,et al.  Generalized velocity obstacles , 2009, 2009 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[4]  Elon Rimon,et al.  The speed graph method: Time optimal navigation among obstacles subject to safe braking constraint , 2014, 2014 IEEE International Conference on Robotics and Automation (ICRA).

[5]  Thierry Fraichard,et al.  Inevitable Collision States: A probabilistic perspective , 2010, 2010 IEEE International Conference on Robotics and Automation.

[6]  Vicente Milanés Montero,et al.  Smooth path and speed planning for an automated public transport vehicle , 2012, Robotics Auton. Syst..

[7]  Friedrich M. Wahl,et al.  Online Trajectory Generation: Basic Concepts for Instantaneous Reactions to Unforeseen Events , 2010, IEEE Transactions on Robotics.

[8]  A. Sim,et al.  MOBILE ROBOT TRAJECTORY PLANNING WITH DYNAMIC AND KINEMATIC CONSTRAINTS , 1994 .

[9]  J. Bobrow,et al.  Time-Optimal Control of Robotic Manipulators Along Specified Paths , 1985 .

[10]  Dinesh Manocha,et al.  Reciprocal collision avoidance with acceleration-velocity obstacles , 2011, 2011 IEEE International Conference on Robotics and Automation.

[11]  Urbano Nunes,et al.  Trajectory Planning with Velocity Planner for Fully-Automated Passenger Vehicles , 2006, 2006 IEEE Intelligent Transportation Systems Conference.

[12]  Thierry Fraichard,et al.  A Short Paper about Motion Safety , 2007, Proceedings 2007 IEEE International Conference on Robotics and Automation.

[13]  Qi Zhu,et al.  A sampling-based local trajectory planner for autonomous driving along a reference path , 2014, 2014 IEEE Intelligent Vehicles Symposium Proceedings.

[14]  Hajime Asama,et al.  Inevitable collision states. A step towards safer robots? , 2003, Proceedings 2003 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2003) (Cat. No.03CH37453).

[15]  Zvi Shiller,et al.  Dynamic motion planning of autonomous vehicles , 1991, IEEE Trans. Robotics Autom..

[16]  Christian Laugier,et al.  Path-velocity decomposition revisited and applied to dynamic trajectory planning , 1993, [1993] Proceedings IEEE International Conference on Robotics and Automation.

[17]  Claudio Melchiorri,et al.  Trajectory Planning for Automatic Machines and Robots , 2010 .

[18]  Thierry Fraichard,et al.  Trajectory planning in a dynamic workspace: a 'state-time space' approach , 1998, Adv. Robotics.

[19]  Kang G. Shin,et al.  Minimum-time control of robotic manipulators with geometric path constraints , 1985 .

[20]  S. Zucker,et al.  Toward Efficient Trajectory Planning: The Path-Velocity Decomposition , 1986 .