@article {121,
	title = {Robot coordination using task-priority and sliding-mode techniques},
	journal = {Robotics and Computer-Integrated Manufacturing},
	volume = {30},
	year = {2014},
	pages = {74 - 89},
	abstract = {<p>In this work, an approach based on task-priority redundancy resolution and sliding mode ideas is proposed for robot coordination. In particular, equality and inequality constraints representing the coordination of the multi-robot system are considered as mandatory (for instance, rigid-body manipulation constraints to distance between the end-effectors of several robot arms, or other inequality constraints guaranteeing safe operation of a robotic swarm or confining the robot{\textquoteright}s workspace to avoid collision and joint limits). Besides the mandatory constraints, other constraints with lower priority are considered for the tracking of the workspace reference and to achieve secondary goals. Thus, lower-priority constraints are satisfied only in the null space of the higher-priority ones. The fulfillment of the constraints is achieved using geometric invariance and sliding mode control theory. The validity and effectiveness of the proposed approach are substantiated by 2D and 3D simulation results using two 3R planar robots and two 6R PUMA-762 robots, respectively.</p>
},
	keywords = {Collision avoidance},
	issn = {0736-5845},
	doi = {http://dx.doi.org/10.1016/j.rcim.2013.08.003},
	url = {http://www.sciencedirect.com/science/article/pii/S0736584513000598},
	author = {Gracia, Luis and Sala, Antonio and Garelli, Fabricio}
}
@article {134,
	title = {Reactive Sliding-Mode Algorithm for Collision Avoidance in Robotic Systems},
	journal = {Control Systems Technology, IEEE Transactions on},
	volume = {21},
	year = {2013},
	month = {Nov},
	pages = {2391-2399},
	abstract = {<p>This brief presents a reactive reference conditioning algorithm for robot collision avoidance based on geometric invariance and sliding-mode (SM) ideas. First, constraints are defined in terms of the measurements given by the robot{\textquoteright}s sensors in order to guarantee that collisions will not occur. Then, a supervisory loop ensures the fulfillment of the constraints modifying the reference trajectory as much as necessary by means of a discontinuous control law. The proposed algorithm activates only when the constraints are about to be violated and, thus, in contrast to conventional SM approaches, there exists no reaching mode to the limit surface of the constraints (sliding surface). The validity and effectiveness of the proposed approach is substantiated by simulation and experimental results using a mobile robot equipped with infrared sensors.</p>
},
	keywords = {Collision avoidance, constraint limit surface, constraint violation, discontinuous control law, geometric invariance, infrared detectors, infrared sensors, mobile robot, mobile robots, Motion planning, reaching mode, reactive reference conditioning algorithm, reactive sliding-mode algorithm for collision avoidance in robotic systems, reference conditioning, reference trajectory, robot collision avoidance, Robot sensing systems, robot sensors, Sliding mode control, sliding surface, sliding-mode (SM) control, supervisory loop, trajectory control, variable structure systems},
	issn = {1063-6536},
	doi = {10.1109/TCST.2012.2231866},
	author = {Gracia, Luis and Garelli, Fabricio and Sala, Antonio}
}
