Chief Delphi - Encoder

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Quote:

Originally Posted by nickmcski (Post 1446459)

We wired the cables like so:

(This image is not mine, I just found it online)

The encoders should be connected to DIOs, not PWM ports!

Quote:

Originally Posted by GeeTwo (Post 1446542)

The encoders should be connected to DIOs, not PWM ports!

Yes, I agree, that diagram can be misleading out of context. The "PWM" in the diagram refers to the use of PWM cable/connectors.

In context (i.e. on the web page where the diagram came from) it explicitly says to connect the cable to DIO ports.

is there any reason why i wouldnt get an accurate reading from the encoders?

Quote:

Originally Posted by Fauge7 (Post 1446608)

is there any reason why i wouldnt get an accurate reading from the encoders?

To avoid having two separate conversations about two unrelated questions in the same thread, it would be best if you started a new thread if your question is not related to the OP's question; and provide more detail about the problem you are experiencing.

Quote:

Originally Posted by nickmcski (Post 1446459)

These are the encoders our team purchased http://www.andymark.com/product-p/am-0180.htm and they are working extremely well for us. One thing we want to try is wiring them directly up to our talons (You can only do this if you have the talon SRX's).

If you cant wire them up to the talons then wire them up to the roboRIO, our team accomplished this by cutting up 2 unneeded PWM cables. We wired the cables like so:

(This image is not mine, I just found it online)

Then we programmed them link this

Code:

        Encoder encoderleft; //Declare the encoders so they are accessible in all methods 

        Encoder encoderright;



        public void robotInit() {

                encoderleft = new Encoder(0, 1); //Initalize the encoder, A channel is plugged into DIO 0, B channel DIO 1.

                encoderright = new Encoder(2, 3);



                encoderleft.setDistancePerPulse(0.11); //did some math to calculate that for 1 pulse the robot moved 0.11 of an inch (Will be different for other robots) 

                encoderright.setDistancePerPulse(0.11);

        }



        public void autonomousPeriodic() {

                double distance = (encoderleft.getDistance() + encoderright.getDistance()) /2; //Find the distance robot has travled based off of the average of the 2 encoders. 

                





                //Code to make your robot move off of the encoder values here

        }

Does that encoder work with the 2015 KOP chassis gearboxes? The video tutorial on the item page shows a different gearbox, so I just want to make sure it works with the KOP one.

We should have added encoders a while ago before bag & tag, but since we didn't we will be adding them during the 6-hour robot access period the week of our first district event. Currently our autonomous modes are based on a timer which isn't very accurate or predictable.

Quote:

Originally Posted by NathanCJohnson (Post 1447173)

Currently our autonomous modes are based on a timer which isn't very accurate or predictable.

What kind of drivetrain do you have?

Quote:

Originally Posted by NathanCJohnson (Post 1447173)

Our team didn't get the KOP drive train but on andymarks website they say that the KOP gearbox is compatible with the type of encoders I linked.

Here is the information about the gear box if you want to look at its specification for the encoders http://www.andymark.com/product-p/am-2598.htm

Quote:

Originally Posted by nickmcski (Post 1447206)

yeah are they compatible? my team ran into the same problem...they are mounted but it seems they are not giving us a very reliable rate

Quote:

Originally Posted by Ether

What kind of drivetrain do you have?

We're using the one that came in the Kit of Parts (http://www.andymark.com/AM14U2-p/am-14u2.htm). But we're using 6" traction wheels in the front and 6" omniwheels in the back (the middle wheels are the 4" wheels that came with the KOP drivetrain).

Quote:

Originally Posted by nickmcski (Post 1447206)

Alright, thanks! I think we'll order a couple (hopefully they'll come fast enough) and we can add them during the robot access period and get autonomous working with them.

Quote:

Originally Posted by NathanCJohnson (Post 1447374)

we're using 6" traction wheels in the front and 6" omniwheels in the back (the middle wheels are the 4" wheels that came with the KOP drivetrain).

Are you powering all 6 wheels? How?

Quote:

Originally Posted by Ether (Post 1447385)

Are you powering all 6 wheels? How?

Two CIM motors power the gearbox which moves the middle wheel. The front and rear wheels are powered by the middle wheel with belts. We use tank drive to actually drive and steer it.

Quote:

Originally Posted by NathanCJohnson (Post 1447439)

Two CIM motors power the gearbox which moves the middle wheel. The front and rear wheels are powered by the middle wheel with belts.

You said the middle wheels are 4" and the front/back are 6". Have you geared them in the proper 6:4 ratio so they are going the same tangential speed?

Quote:

Originally Posted by NathanCJohnson (Post 1447374)

Quote:

Originally Posted by Ether (Post 1447443)

You said the middle wheels are 4" and the front/back are 6". Have you geared them in the proper 6:4 ratio so they are going the same tangential speed?

Unless the chassis has been modified (drilled more holes) it isn't necessary. The center axle on the AM14U2 is only dropped 1/8". Since the corner wheels are 2" larger diameter, the 4" center wheels float 7/8" off the carpet. In effect, the 4" wheels are just a spacer for the belt sheaves.

We did something similar with our H-drive, though since we used 4" wheels on the corners, we cut the rubber off the center wheels so they would float.

Quote:

Originally Posted by GeeTwo (Post 1448190)

the 4" center wheels float 7/8" off the carpet.

Except when going over the platform.