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Unread 19-05-2005, 05:32
N7UJJ N7UJJ is offline
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AKA: Allan Cameron
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Re: One Joystick Drive

Quote:
Originally Posted by mattsavela
We finally got a chance to test our robot in the pool. The robot worked fine going forwards, and turning. However, when we pull our joystick backwards, the robot goes forward, and when we push the joystick forward, our robot goes backwards. Is there a way you guys can help me fix that? Also, our robot does not goes very fast when it is moving backwards, but moves at a good speed when it goes forwards. Is there a way to make it so that when we go backwards, it goes the same speed as it goes when going forwards?

Thanks
There are two solutions to the forward/backward problem:

1. transpose the wires from the motor speed controller that go to the motor by switching the M+ and M- wires. (I think this is the best solution)
OR
2. in the code, add pwm01 = 255 - pwm01;
pwm02 = 255 - pwm02; // put after any other assignments to pwm01. (I used PWM01 Ind 02, but of course, use the pwm## that the motors use

As for the different speeds, there can be three solutions:
1. calibrate the motor speed controllers
2. in the code,use a lookup table or a function so that the p1_y goes from 0 - 255
3, It may be the motors, They just may go faster in one direction or its the water flowing more efficiently in one direction that the other. Not much you could do about that.

Fix the direction problem first and test in the water. Maybe the speed problem will go away or not be so noticeable.

Let me know what happens

Allan