simultaneous rotations

[legobob]

I'm trying to rotate two motors simultaneously. What I've tried is the code:

Motor.A.rotate(120);
Motor.B.rotate(90);

This first rotates motor A 120 degrees and then rotates motor B 90 degrees. I want both motors to start rotating at the same time. Anyone know how I can do that?

[gloomyandy]

Try...
http://lejos.sourceforge.net/nxt/nxj/api/lejos/nxt/Motor.html#rotate(int,%20boolean)

Note the extra parameter....

[legobob]

That worked. Thanks

[plotterbonger]

Hi! Try this:
Motor.A.rotate(120, true);
Motor.B.rotate(90, true);

This way, the calls will return immediately, resulting in the motors starting simultaneously. My current project is a plotter, and when drawing a straight line I need to start the paper feeder and the carriage motors at the same time too.

The problem I am about to work around are these:
- Some time passes between the execution of the two commands, resulting in the motors not starting exactly at the same time.
- The speed of the motors need to be carefully adjusted according to the direction of the line to be drawn.
- The synchronization of the accelerations seem to be the biggest problem. Each line my plotter draws starts to be drawn in an awkward direction, and it takes a few millimeters until the right direction is achieved through proper adjustment of motor speeds.

[tsanalp]

what worked?

[gloomyandy]

Hi,
For some reason my post does not show up correctly in some browsers. It was a pointer to the leJOS documentation for the version of rotate that takes two parameters. The second parameter tells the rotate call not to wait for the move to complete and so enables more than one motor to run at once...

Andy

[choncha]

Hi @all

I want to rotate the motors simultaneously, too... I found the method with the immediateReturn argument but somehow this is not working for me. The documentation also says "If any motor method is called before the limit is reached, the rotation is canceled." I try to let one motor go forward and one backward to rotate on the spot. As long as "immediateReturn" is set to "true" the robot is doing nothing. If it's set to false it works like the other rotate method without the 2nd paramter. How can I make the robot rotating both wheels in different directions simultaneously? Thanks for helping!

[TechnoX]

Can you post your code here?
It should work without problems...