Help with motion of the car - Displacement

sophiecentaur

We may be talking about different things. There are many parking aids that tell you when you are too near the car behind. I thought the suggestion here was for far cleverer functions.

ZapperZ

This thread is veering into non-physics issues. If it doesn't get back on-topic for the forum it was placed in, it will be closed.

Zz.

d3mm

The OP is discussing a system that measures parking spaces to determine if the car can fit.

I was talking about a system that combines this with operating the steering, to get the car into the space. These have existed on certain new cars since at least 2003.

sophiecentaur

Interesting. Which cars? Is there a link that you would recommend?

sophiecentaur

I looked at a couple of You tube movies. Quite impressive but I don't think it would get into the spaces available in my street. I need castors and side thrusters!

d3mm

toyota yaris 2010 (was the first hit on youtube, but it;s older than that)

http://www.youtube.com/watch?v=2eng94_flJw

mrspeedybob

Vehicle speed is computed by measuring the time between pulses from vehicle speed sensor. This sensor changes it's output based on the presence or absence of a tooth on a rotating gear in the transmission, differential, or wheel bearing. The output may be a square wave in the case of a hall effect sensor or and AC sine wave from and magnet/coil type of sensor. In either case, each cycle = 1 tooth on the gear. It would be fairly easy to measure distance directly from the speed sensor signal because each tooth represents a certain amount of distance traveled (within the margin of error associated with tire wear and inflation). There would be no need for numerical integration and the associated additional error.

If you are trying to build a 1-of system you may be able to tap the speed sensor circuit and run a signal wire directly to your module. If this is an engineering project for an auto manufacturer you might send a memo to the guys writing the ECM, TCM, or ABS code and ask if they could put raw distance data as measured by a speed sensor on the communications circuit for your program to use.