COMPACTlaser Multiple Light Beam Safety Devices for safeguarding in a collision simulator

Safe collisions

Leuze: When designing a collision system, there are challenges not only with the construction of a damping system and the integration of acceleration sensors: safeguarding also means a great challenge. Strict safety regulations must be satisfied with such a system, since there is an acute risk of injury during operation. The safeguarding was realised with Multiple Light Beam Safety Devices from Leuze electronic.

At the University of Applied Sciences in Constance (Hochschule Konstanz Technik, Wirtschaft und Gestaltung, HTWG), a collision simulator is currently being developed in the measurement and sensor laboratory of the Institute for Natural Sciences and Mathematics (Institut für Naturwissenschaften und Mathematik, INM) under the direction of Professor Klaus Durst. Positioned on a guide block is a seat with a test person. The seat with person is driven with a defined acceleration and speed against a shock absorber, thereby simulating a vehicle collision. Various sensors record the different measured parameters during the event.

During the development of the safety concept by the project engineers, Sandro Folisi and Janek Stahl, it was determined that there are two types of potential danger during operation of the collision simulator. One is the improper operation of the system. The other is the danger of external influences, such as persons entering the danger area. The danger that arises from improper operation is minimised through the use of a checklist created for this purpose. Furthermore, the system may only be operated by trained, qualified personnel. The safety risk resulting of persons entering the danger area had to be eliminated by means of a concept with high safety level.

With system dimensions of 7 x 2.5 x 1.5 m, a Multiple Light Beam Safety Device was determined to be ideal for ensuring protection of the entire system, which had to remain accessible. Following an extensive research by the project engineers, it was decided to use the three-beam COMPACTlaser system from Leuze electronic. This is a type-4 Multiple Light Beam Safety Device acc. to IEC/EN 61496.

The sensor is mounted so that the bottommost beam is positioned at a height of 300 mm and a total protective field height of 1100 mm is achieved at a beam distance of 400 mm. Crawling under, running through and jumping over are, thereby, reliably prevented. The safety system consists of a transmitter and a receiver. Safeguarding the entire system from all four accessible sides was realised by means of three Deflecting Mirrors. Special spring elements in the base of the free-standing Deflecting Mirror Columns ensure that they are automatically reset to their adjusted position after slight mechanical impacts.

To meet the requirement of a shortest possible commissioning time and maximum alignment quality with wide-range safeguarding, the Multiple Light Beam Safety Devices feature an integrated red-light alignment laser on each light axis. With the visible laser spot, the system can easily be set up and aligned.

The system is connected to the control of the collision simulator via a potential-free relay. With the response behaviour of the Multiple Light Beam Safety Device, the short signal transmission time of the potential-free relay and the stop response of the simulator, the small minimum distance of approximately 1 m could be computed with support from the Leuze electronic Machine Safety Service Team. According to project engineer Sandro Folisi, the system from Leuze electronic reliably safeguards the collision simulator with respect to the access of persons.