This paper presents a new method for online path planning for robotic arms in dynamic environments. Most online path planning methods are based on local algorithms that end up being inefficient due to their lack of global information (local minima problems). The method presented in this paper avoids local minima by using a two stage framework. The robots react to dynamic environments using a local and reactive planning method restricted to a subset of its configuration space. Since the subset has few degrees of freedom the computational cost of the online stage is very low. An off-line stage chooses the subset of the configuration space that minimizes the probability of blockades and inefficient motions.

In a multirobot system (MRS) several robots can operate simultaneously on the same product, and allow the accomplishment of tasks that a single robot could not approach due to restrictions associated to the product and/or the robot. We propose a MRS consisting of three robots and four different working platforms, that allows the characteristics of joint operation to be maintained even if a robot is out of service. In order to make a detailed analysis of the operating characteristics of the MRS we propose to use timed Petri nets (GSPN and DSPN), than allow the efficiency of the system to be evaluated. This paper analyses the influence of the robot maintenance and failures on the throughput of an MRS, under different conditions of operative configuration, number of subtasks, degree of interference, operation mode on the product, etc.

This work describes a path planning method applied to a three robot system. Trajectories are optimized to allow minimum time performance of the overall system. Mathematical programming methods with a global approach are used.