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New Sensor Provides An All-round View For Robots

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New Sensor Provides An All-round View For Robots
New Sensor Provides An All-round View For Robots

Video: New Sensor Provides An All-round View For Robots

Video: New Sensor Provides An All-round View For Robots

For precise work, it is essential that robots in production know exactly where they are and what is around them. So far, however, robots have mostly not been able to see in all directions, which limits their work. The Sensepro laser sensor, developed by the Fraunhofer Institute for Additive Production Technologies IAPT, is intended to remedy the situation.

Sensors restrict the robots' freedom of movement

When robots tirelessly glue, weld or seal workpieces, they have to work extremely precisely. The robot controller must know exactly where the adhesive or welding head is at the millimeter so that the result is precise. So the robot needs a kind of eye. In the automotive industry and many other industries, special sensors take over, most of which work with the principle of laser triangulation. A laser diode throws a line of red light onto the workpiece, from there the light is reflected at a certain angle and then thrown into a camera. The position and the distance of the sensor from the workpiece within the coordinate system can be determined from the position from which the light hits the camera chip.

Conventional sensors limit the robot's directional flexibility
Conventional sensors limit the robot's directional flexibility

However, there is a problem here, explains Mauritz Möller, Head of Factory Systems for Additive Manufacturing at the Fraunhofer IAPT facility: The flexibility of the existing sensors is limited by shadowing, they also restrict the freedom of movement of the robot systems and lead to a high level of integration. “With conventional sensors, height measurement only works if they are attached in the processing direction. If the direction of movement of the robot changes with these sensors, the eye remains blind. The definition of a processing direction clearly limits the flexibility of the handling systems. The only alternatives are the use of several sensors or additional axes - both are sometimes more expensive than the robot itself according to the current state of the art.

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Sensor provides a complete all-round view

Mauritz Möller has developed a new solution with his colleagues Malte Buhr, Vishnuu Jothi Prakash and Julian Weber: The Sensepro sensor with a diameter of 15 cm has a specially developed evaluation sensor system that enables a shadow-free all-round view. The sensor thus creates a 360 ° measuring curtain that offers complete flexibility in the measuring direction. No matter where the robot is moving, at least one laser line is always optimally positioned and provides precise position information to the camera. In addition, there should be no shadowing of the light due to complexly shaped components. The measuring principle has now been patented. According to the researchers, the user can use the sensor for all robot systems flexibly and reliably in gluing and welding processes without the need for integration and achieves simplified process control and quality assurance.

3D printed cooling structure ensures long life

In order to be able to work in harsh production environments for a long time, the sensor contains a cooling module that works with either water or air. For this purpose, the optical bench on which the laser diodes and the cameras are mounted has an internal cooling structure. This is so complex that it can only be produced in 3D printing. Thanks to intelligent thermal management, the sensor should last for many years. The sensor is designed in such a way that it fits on robots of all common manufacturers and is suitable for all application scenarios. This should allow easy integration into existing manufacturing plants. Sensepro is expected to be ready for series production in 2021.

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