%0 Conference Paper %1 Simas_et_al07:COBEM07_collision %A Simas, Henrique %A da Cruz, Daniel Fontan Maia %A Guenther, Raul %A Martins, Daniel %B Proceedings 19th International Congress of Mechanical Engineering - COBEM %C Brasilia - DF %D 2007 %K imported %T A COLLISION AVOIDANCE METHOD USING ASSUR VIRTUAL CHAINS %X In hydroelectric power plants, the rotor blades are eroded by the cavitation process. The erosion results in craters that are usually recovered by a manual welding process. The ROBOTURB project developed an automatized system, where a robot is used for recovery the rotor blade surfaces by welding process. The robot workspace is constrained by freeform surfaces and the collision imminency is constant. For this reason, the robot is redundant, making possible the collisions avoidance, keeping the end-effector trajectory tracking. In recent years, the collision avoidance problem has been dealt with algorithms based on artificial intelligence. This article considers a methodology for implementation a deterministic collision avoidance algorithm. The base of this proposal is the Assur virtual chains. The method consists in the obstacle identification and in the definition of a free collison workspace area. Thus, it is used a Assur virtual chain to detect and avoid the collision by evaluating the distance between a point at the robot and the obstacle. The Assur virtual chain is responsible for maintaining the robot inside the free collision workspace. This process is carried out for each point of the desired trajectory. To complement the application, a smoothing transition algorithm is presented in a way to avoid abrupt changes of robot joint speeds and/or accelerations. %Z Submitted

@inproceedings{Simas_et_al07:COBEM07_collision, abstract = {In hydroelectric power plants, the rotor blades are eroded by the cavitation process. The erosion results in craters that are usually recovered by a manual welding process. The ROBOTURB project developed an automatized system, where a robot is used for recovery the rotor blade surfaces by welding process. The robot workspace is constrained by freeform surfaces and the collision imminency is constant. For this reason, the robot is redundant, making possible the collisions avoidance, keeping the end-effector trajectory tracking. In recent years, the collision avoidance problem has been dealt with algorithms based on artificial intelligence. This article considers a methodology for implementation a deterministic collision avoidance algorithm. The base of this proposal is the Assur virtual chains. The method consists in the obstacle identification and in the definition of a free collison workspace area. Thus, it is used a Assur virtual chain to detect and avoid the collision by evaluating the distance between a point at the robot and the obstacle. The Assur virtual chain is responsible for maintaining the robot inside the free collision workspace. This process is carried out for each point of the desired trajectory. To complement the application, a smoothing transition algorithm is presented in a way to avoid abrupt changes of robot joint speeds and/or accelerations.}, added-at = {2008-03-02T02:12:02.000+0100}, address = {Brasilia - DF}, annote = {Submitted}, author = {Simas, Henrique and da Cruz, Daniel Fontan Maia and Guenther, Raul and Martins, Daniel}, biburl = {https://www.bibsonomy.org/bibtex/253cb9b463ec2d02300a87b3e2a54891c/dmartins}, booktitle = {Proceedings 19th International Congress of Mechanical Engineering - COBEM}, description = {robotica-bib}, interhash = {8225077c65f7c54efb1ad3df654cc672}, intrahash = {53cb9b463ec2d02300a87b3e2a54891c}, keywords = {imported}, timestamp = {2008-03-02T02:14:21.000+0100}, title = {A COLLISION AVOIDANCE METHOD USING ASSUR VIRTUAL CHAINS}, year = 2007 }