The UnCoVerCPS Project
This collaborative European research project was concerned with the development of faster and more efficient development processes and for safety- or operation-critical cyber-physical systems. Within this larger project, RU Robots applied the technology to their GRAIL Robot System.
Method of operation
The UnCoVerCPS approach uses an online verification technique to ensure that any proposed movements of the robot are guranteed to be collision free. It operates by dividing the motion of the robot up into small time segments. These motion segments are then compared with all possible movements of the co-workers based on the data from the available sensors. In the case of the GRAIL Robot System, light-curtains were used as the safety sensors. In the case of light curtains, all that is known is that the co-worker is either behind the light curtain (the light beams are unbroken) of is between the light curtain and the robot (the light beams are broken)
The Plan Selector
The method described above makes the system safe, but it does not gurantee efficient operation of the robotic system.
An additional software module, the Plan Selector, has been developed to improve this efficiency. At any moment in time the GRAIL Robot has a number of different possible operations that it could carry out since there are a number of ingredients and bases with its reach. The purpose of the Plan Selector is to choose the operation that is least likely to suffer a collision with a co-worker from the set of possible operations . It does this by using data from additional sensors to determine the current position and likely actions of any nearby co-workers.
A number of different factors are combined in a weighting function to determine the best action to take including the time taken to perform a particuar pick and place operation, its predicted proximity to co-workers and its usefulness in completing sandwiches.
The combination of the two methods described above results is a system that is both safe and has high efficiency when there are co-workers that could collide with the robot arm.
The UnCoVerCPS Project received financial support from the European Commision under grant number 643921.