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ionutdinulescu
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drive pc-bot backwards - 2008/04/17 18:54 Hi,
I'm currently evaluating the pc-bot 914.
how can I drive it backwards ?
I tryed with negative distance and speed, but it's not working.


thanks
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c6jones720
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Re:drive pc-bot backwards - 2008/04/17 22:39 I havent tested it, but possibly you might not be able to do that because there are no sensors on the rear of the robot.
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jamesbruton
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Re:drive pc-bot backwards - 2008/04/18 05:00 The hardware does support being able to turn the wheels backwards. What software are you using - Player/Stage, .NET controls, BRIAN etc?

If you're using the .NET controls then there are two ways of driving:

1) just setting the left and right velocity values as well as the power value. The velocity values can take a value from -100 to +100 which will allow you to go backwards.

2) with the 'drive a distance' function, but this does not allow you to drive backwards as valid values for velocity are only 0 to +100.

The only disavantage with (1) is that you can't tell how far you've gone, so you have to use a timer or some other event to stop... and there are no sensors in the back of the 914, so be careful.

Post edited by: jamesbruton, at: 2008/04/17 21:14
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c6jones720
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Re:drive pc-bot backwards - 2008/04/18 17:21 When you drill right down to the PMD code the drive distance does allow you to reverse, but like you say its the velocity thats not allowed to be negative.
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lilytherobot
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Re:drive pc-bot backwards - 2008/05/17 06:04 Th way I've handled this is to set the left and right velocitys to be negative (which makes the wheels spin backwards and move the 'bot backward) and then to calculate how long to wait until the movement is done.

I know the speed, and I know the distance, therefor I can calculate time. (D=R*T).

Dave...
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