Radar-based collision protection moves closer to the shop floor

Related Vendors

HASCO Hasenclever GmbH + Co KG

Renishaw plc

DIPROFIL Diamantprodukter AB

Technische Universität München Umwelthygiene

If it works for cars, why not machine tools?

This sweeping triumph of radar sensors inspired the specialists at Ott-Jakob Spanntechnik with the idea of incorporating into their motor spindles precisely the technology that has long been preventing crashes in aircraft and cars. An especially favourable circumstance in the plan was the geographical proximity to Munich Technical University, where, in the department of high frequency technology, there is a research group whose work is constantly concerned with improving the capabilities of radar sensors. It was there that a sensor concept was developed that aims to protect in future the tools in processing centres from so-called geometric collisions. This kind of collision includes all crashes between the tool spindle and other machine parts during positioning.

Fencing in the spindle to protect it from crashes

The idea is to set up an invisible encircling protective fence of several small radar modules around the tool. The photo to the right shows a laboratory construction that is used for measurements and series of experiments. It consists of a holder that accommodates the radar modules and the pertinent amplifiers for signal conditioning. The radar module is of a size that will later also be suitable for incorporation into the motor spindles at Ott-Jakob.

The special factor here is that the radar sensors involved are of very simple construction and can thus be purchased at low cost. They require no large transmission power and need not produce short impulses as, for example, in weather radar. As only objects in motion are to be detected, it is quite sufficient if the modules send out a continuous signal. A modulator, which would make the system much more complicated and more expensive, is not required.

The radar principle that applies is very closely related to the measurement principle in radar equipment used for detecting road speed infringements. When the electromagnetic waves sent out from the radar are reflected back to the unit by a moving obstacle, the frequency of the received signal is changed as a result of the relative motion. This is known as the Doppler effect, which also occurs with sound waves, something everyone has certainly observed when a fire engine drives by. Through this frequency change it is possible to tell whether the object is moving away from or towards the radar. But there’s more: if one measures this frequency change with spectral analysis procedures such as Fourier transformations, it is also possible to calculate the relative speed of the object.

(ID:42227500)