The system, which was developed by MDUSpace at the European Space Agency’s (ESA’s) Business Incubation Centre in the Netherlands, is based on the object recognition and tracking concepts used for the automated docking of the ESA’s Automated Transfer Vehicle (ATV) spacecraft to the International Space Station (ISS). It was installed at the Palmela factory last year and is now being evaluated.
‘Automotive assembly lines are based on moving conveyor belts that transport the cars to be assembled at a steady, but not constant, speed,’ said Miguel Brito, business developer of MDUSpace. ‘The car is assembled by workers or robotic machines at each assembly station along the way.
‘When you have to attach a module to the car, for instance the car’s dashboard, the mounting is done by a manipulator — a large manually controlled robotic part positioner. As the cars move along the belt, the manipulator needs to move at the exact same speed. If it goes any slower or faster than the car, it could scratch or damage it.’
The traditional methods of solving this problem are either to place the manipulator on the car during the assembly process, which can stress the vehicle’s structure, or to synchronise their speeds, which often requires costly and complicated control and wiring systems.
The new system, however, can synchronise the manipulators with the car. It combines a live camera feed with software for object recognition, derived from spacecraft docking systems, to make sure the manipulator and the car go at exactly the same speed and are in the same position with respect to each other at all times.
It works like an automated transfer vehicle (ATV) docking with the ISS. For the final approach and docking, an ATV uses a camera to identify light pulses reflected from a set of special targets on the ISS.
By analysing the reflected patterns, the control software determines the precise distance and angle to the docking port.
In the car assembly process, the operator chooses reference points on the car as targets for the object recognition system. It then calculates the distance from the manipulator to the car and automatically holds their relative position.