Optical scanning devices for collision protection on automated guided vehicles

Status:

completed 12/2000

Aims:

Guideline ZH 1/473 governing automated industrial trucks requires that such trucks be equipped with a device for protection against collision in the direction of travel. Electrosensitive collision protection devices have been developed within industry and are now available to supplement the mechanical collision protection systems which have been in use for some time. Electrosensitive collision protection devices employ optical scanning. The objective of the project was to examine the inherent suitability of such systems for collision protection. The study was commissioned by the "Conveyors and Load Suspension Devices" BG expert committee, and was conducted parallel to the development of actual products for industrial manufacture.

Activities/Methods:

The weak points were analysed systematically in order to permit assessment of the probability of detection, measuring principle, effects of ageing, and the influence of temperature and pollution. Analysis involved both the use of theoretical procedures and tests on actual products. The individual sensor and circuitry concepts were assessed in detailed studies of the principles. The measures detailed in DIN V VDE 0801, "Principles for computers in safety-related systems" were employed.

Results:

The studies performed within the scope of the project on three different optical scanning systems demonstrated that the deficiencies inherent to the systems can be controlled by suitable technical measures. The results of the studies have been incorporated into the requirements and test procedures contained within a test recommendation issued by the BG Institute for Occupational Safety (BIA) and the final draft of an international/European standard (IEC 61496-3: Safety of machinery: Electro-sensitive protective equipment - Part 3: particular requirements for equipment using active opto-electronic devices responsive to diffused reflection (AOPDDR)(08.2000)). Optical scanning devices which enable protective zones of different dimensions to be selected according to the speed of the vehicle are of particular interest for use on automated guided vehicles. Speed-dependent protective zones enable the size of the protective zone to be adapted to the local conditions and technical processes. The study also demonstrated safe implementation of these processes.

Further informations:

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