Industrial Targetting Help Needed

[Rizz]

I need some ideas to help make sure a dump truck bed is located properly under a silo.  I have considered IR, Ultrasonic and laser but the application will have steam, dust, etc.  This is an outdoor application.  I was worried about the optics (in the case of the IR and Laser) and the going from one media (air) through another (steam). 
Any ideas?

[Admin]

An actual real dump truck and silo?
(sorry, but people all the time forget to mention they are in a competition on this site )

All those methods you mentioned won't work if its really steamy/dusty.

Radar will work however. There are various handheld radar devices you can buy and hack into - police radar, and even a toy:
http://www.edparadis.com/radar/

You will have to do experiments to see how far they go in your environment . . .

[airman00]

maybe use triangulation with RF ?

[bukowski]

In industrial applications, your best bet would probably be an electro mechanical solution, something like a couple of switches where the tires should be. The odds are you can get a NEMA enclosure for protecting any delicate circuitry from steam and dust, but protecting it from truck drivers and industrial workers is another matter.

[airman00]

In industrial applications, your best bet would probably be an electro mechanical solution, something like a couple of switches where the tires should be. The odds are you can get a NEMA enclosure for protecting any delicate circuitry from steam and dust, but protecting it from truck drivers and industrial workers is another matter.

yea thats a good idea bukowski

have 4 switches on the where the tires should be , and then you can know when the vehicle is properly aligned when all 4 switches are closed( meaning each switch has a tire

[Rizz]

Thanks for the feedback.  I forgot to mention this is a safety measure to prevent dropping tons of hot asphalt onto a truck roof or windshield where someone could get hurt.  We are talking about real dump trucks in a steamy - dusty environment.  The trucks recieve three "drops" of hot asphalt from the silo. The truck readjusts position between the drops.  A big problem in this process is that there are several different makes and models of dump trucks that carry the asphalt.  I was thinking of mounting some device (laser of ultrasonic device) above the trucks near the silo cone.  I was thinking the void of the truck bed could be sensed and the center could be determined.  Even if this a viable idea, sensing the truck bed position for the second and third drops would be very difficult because the asphalt from the previous drop would interfere with the sensing of the truck bed.   I was thinking of a different type electro-mechanical application.  Some method of measuring the truck before it gets under the silo that resets a sensor that senses the truck while it is under the silo.  I still have no idea how to tell if the truck is in a "good" position to recieve all three drops.
Any more ideas?

[airman00]

my ideas using RF triangulation sounds feasible for your application

[Admin]

I still have no idea how to tell if the truck is in a "good" position to recieve all three drops.
Any more ideas?

I'm not sure what the visibility is, but if you put white lines/reflectors where the truck should be on the ground, then you could use computer vision.

Each size truck would result in a set of lines (3 diff size trucks result in 3 boxes inside each other), so mathematically you can determine which truck is there (and if it is misaligned) by detecting which lines/reflectors are covered up when a truck drives over it.

Or instead of lines, use bright lights.

[Rizz]

Thanks again for the ideas.  I have been looking more closely a dump trucks recently.  When looking at the side of the truck, it was pointed out to me that there is a gap between the cab and "box" about even with the door handle.  I am thinking of using a ultrasonic or laser sensor to find this opening and work off of it to find the front edge of the truck bed.  I am thinking of using a second sensor located near the silo discharge cone to determine distance from the cone.  If the distance is in a preset range, the truck will be assumed to be positioned in such a way that the asphalt should dump into the truck bed.  Any distance greater than the maximum would suggest the truck has moved past the "dump zone".  Any distance less than the minimum may suggest dumping on the cab.  I'm thinking that, if the reflected signal is not too dispersed by the surface of the piles of asphalt in the truck bed, this scheme should work for all three dumps.

Am I going to have trouble with the reflected signal?