VI for autonomous vehicle

[Dublin]

Ok, see this is the kind of questions that I can answer in order to help you.

I'm still not clear based on your comments

Does the SONAR generate a fix frequency PWM signal and changes the Duty Cycle based on the distance of the object, or does it Keep the duty cycle constant (should be 50) and changes the frequency of the signal based on the distance of the object

[rAGIAMLT]

Sir, 

It was not me who asked the full working VI ,in fact we already discussed the SONAR a month back.......

 my  sonar sensor is described as follows:

it has one receiver and transmitter, jus like the DEVANTECH sp05 model, the inbuilt burst pulse is of 40KHZ.

it has single I/O pin, we need to trigger the pin using a pulse of high state time 40micro seconds.

after 200microsecs, it gives output depending on distance from object, the output is given as high state time varying from 100microsec to 32millisec,

therefore we need to trigger and measure the time for which the I/O is at high state, to measure the distance from object.

[ajmartin]

So exactly what is the problem? labVIEW has several ways of determining the pulse width have you looked at that? or is the problem sending the trigger in the first place?

Alan

[rAGIAMLT]

yes, u got my point i have to trigger and receive the signal with very less time gap, measure the high state etc,

[ajmartin]

I just took a quick look at the spec sheet for the  usb 6251, have you looked at this? It looks like your counter can do pulse width measurements, so just set the counter up for that. Send out a pulse on a DIO line and listen back for it on the counter input.

Alan

[dskrabacz]

Hello All,

I am doing something similar but we are building an autonomous vehicle utilizing a Novatel GPS and several IR sensors. At this point, we have been able to get the vehicle moving under autonomous mode. This mode being that we give it specific GPS points, and it starts to go there. We are running into the problem of it losing its bearing and heading calculation.

What happens is the following: we have the vehicle in some initial state, the initial state then goes to a "go" state. This "go" state initializes the motors to begin to move forward. Once it starts moving forward, it gets a steady heading. We had it one time start going back to our desired GPS cooridinate. It started going back, but it was going in a nasty zig zag line. From that point in time, we tried doing the same task, but we could not replicate it. After that test, we give it a desired cooridinate. It beging going in that direction, but then our bearing - heading algorithm begins jumping all over the place. With this jumping all over the place, the algorithm decides to go into a constant turning right state; it will then to continue going in a circle indefinitely.

Any ideas on how to fix this?

-Daniel

[rAGIAMLT]

are you sure ure method of calculation of the bearing is right?

[dskrabacz]

Yes

[rAGIAMLT]

why cant quadrant technique could be used? because ure autonomous robot is restricted only to area given for particular application?