Collision Detection


Thread Starter

Richard King

Hi all,
Does anyone have knowledge of a collision detection system for an Alumina Loader. The loader is on tracks, it has a 15 meter boom
that can extend 15 meters. The loader moves at .5 meters a second. I am looking for a system to protect the boom from hitting ship masts, wires, etc. I have looked into radar, trip wires, laser
and they all seem to be unsatisfactory. On occasion the loader is moved with the boom fully extended.

Any information would be appreciated.

Richard King

Alesa Alusuisse Engineering Australia Pty Limited.
Phone: +61 7 3218 3555
Fax : +61 7 3236 0155
Email: [email protected]
Web :
Responding to Richard King's Mon, 28-Aug, 10:50am query:

Although you mentioned having investigated a trip-wire solution, have you considered a system having the following characteristics:

1) "Loop" a "bare" trip-wire so that it is offset about 1 meter around the boom's perimeter. The actual offset distance will depend upon how
quickly you can stop the Loader. Perhaps two, or more, "planes of detection" will be required to pick up objects that are skewed relative to the boom's motion. Electrically isolate the trip-wire from the metal of the boom. This characteristic will enable detection of "earthed" objects. For this case terminate both ends of the trip-wire to an "earth-fault" detector.

2) The wire should be fragile enough to break when it contacts guy wires or power cables or communication cables, that are not intentionally
earthed. For this case the trip-wire should be connected to a "continuity" detector.

3) The wire should be strong enough to be connected to cable/wire takeup reels to compensate for boom movement. The reels should be installed on the fixed portion of the boom. Because I seriously doubt that you will find a spring-loaded reel that won't impart too much tension to the wire, the reels may have to be motor-driven. They can be activated when the boom is extended or retracted.

4) See our website for our Smart-A-Larm series of modules that will provide both earth-fault and continuity functions in one DIN-rail mounted enclosure

Phil Corso, PE
Trip-A-Larm Corp
(Deerfield Beach, FL)
The problem with booms is quite complex, I have faced problems with trip wires and tilt switches especially during windy days or with material
hitting the tilt switches etc. Proximitors can help to a limited extent if the exact areas that can impact are known. Mounting them is another issue. Cameras can help the operator if everything else fails, however, here again you need to know the most likely places of impact.

Anand Krishnan Iyer.

Richard King

Thanx Phil,
I have considered that option, capacitance options, infrared, laser, Microwave, Ultra Sonic, Loadcell on a continuos tripwire (attached to both ends of moving boom)... and a few others.

I have not found anything that will give 99% reliability and still be acceptable to the maintenance department.

We are seriously looking at using a microwave system on outriggers.

Richard King.

Don Patterson - Schneider Electric

Get with any contacts you may have with Schneider Electric or Square D Company. In the US they have an Industrial Applications Group which offer collision avoidence system for cranes and other equipment. The Industrial Applications phone number 1-800-894-7259. You may also look for Industrial Applications on

The following web site
has a brochure on this subject.
Best Regards,
You could try proximitors with some mechanical mounting modifications, however, you need to know the likely places of impact. You could also try
out cameras and TV in the operators cabin.
Anand krishnan Iyer
Milltronics makes CraneRanger ultrasonic sensor which measures distances from 1.8 m to 60 m (6 ft. to 200 ft.). Petr -- Petr Baum <[email protected]> ------------------------------------ Niksar Pty Ltd Unit 135/45 Gilby Rd, Mount Waverley, 3149 Phone: +61-3-9558 9924 Fax: +61-3-9558 9927 ====================================
Seems to me the question is as much one of implementation as opposed to which sensor. This is a classic weighing up of reliability and availability. It may be easy to find a sensor which gives you a 'fail-safe' condition under any undesirable condition (dirty lens/power fail/cable break) but how much downtime will result? I think redundancy here with some kind of 2-oo-3 vote. If you can combine this with a reliable sensor which has predictable overt and covert failure modes you've cracked it. After all that, no, I can't help you with a sensor as they're not really my bag. Sorry.