Joystick problems

Posted by Andrew wyatt at 03/21/2001 9:05 PM EST

Other on team #524, Alpha Omega Robotics, from South High School.

Has any other team has problems with their joysticks?

We used the stock CH flightstick controllers, and we had nothing but difficulties with them.

Out of the three joysticks we had after the second week, two of them experienced a strong tendency to jump all the way to 255 (full ahead) when pulled all the way to the rear(which should be 0).

When this happened under load, our robot went full reverse, then full foreward in the space if about a half second, shearing the 1/8" pins holding the couplers to the drive shaft.

we had to replace a joystick when we got to the competetion, because of corrosion from the condensation in the box.

Did anyone else have similar problems?

Posted by Ed Sparks at 03/21/2001 9:30 PM EST

Engineer on team #34, The Rockets, from Bob Jones High / New Century High and DaimlerChrysler.

In Reply to: Joystick problems
Posted by Andrew wyatt on 03/21/2001 9:05 PM EST:

I’ve seen this sort of thing before but it was related to the math in our software that controls the motor controller. Interger math can be cruel … Check your software and use MIN MAX statements.

Posted by Matt Leese at 03/21/2001 9:51 PM EST

Other on team #73, Tigerbolt, from Edison Technical HS and Alstom & Fiber Technologies & RIT.

In Reply to: Check Your Math …
Posted by Ed Sparks on 03/21/2001 9:30 PM EST:

To elaborate more on what was said, the problem there would be that the Basic Stamp controller only supports positive math. That causes values to wrap around when they go below zero. So -1 turns into 255. A good idea is to add 2000 to your input before doing calcuations. Applying a MIN and MAX and then subtracting the 2000 back out.

Matt

Posted by Andrew wyatt at 03/22/2001 9:55 PM EST

Other on team #524, Alpha Omega Robotics, from South High School.

In Reply to: Re: Check Your Math …
Posted by Matt Leese on 03/21/2001 9:51 PM EST:

aah. that makes a lot of sense.

thank you so much.