accelerate and decelerate

carmila

i have a circular path, like elips, when i move the robot along the path with the high speed, i saw that the track(of robot) is not the same with path (more roughly), i think that i must add some deceleration. but i don't know how to add the decelarate. can somebody help to explain me? thanks a lot

regards,

 

Anders S

Hi,

If the robot not follows the programmed path, is it probably the "zone" (zone data) in the move instructions that are to large. In the Rapid Help will you find information about zone data and the other arguments for move instructions.

 

jerrico

Hi mrs Carmila, How did you create your path ? I really think that decelerating your speed is not the key .. have you heard Truemove? TrueMove is one of the abb's products that ensures the motion path followed by the robot is the same as the programmed path- regardless of the robot speed.

Henrik Berlin

Hi,

TrueMove and QuickMove are two labels defined to capture the outstanding motion performance of the IRC5 controller. They are part of the system already and need not be added.

from http://www.abb.com/product/seitp327/f0cec80774b0b3c9c1256fda 00409c2c.aspx

"The path accuracy of TrueMove and the short cycle time of QuickMove are corner stones of these user benefits. The addition of MultiMove strengthens ABB's lead in advanced robot systems and functionality that enables the coordinated operation of up to four robots in a cell. "

ABB has recently released the 2nd generation versions of TrueMove and QuickMove with further improved motion performance. They are available for certain robot variants.

jerrico

Hi, I didn't said that truemove is the solution ..  I'm just saying that regardless of the speed .. .the robot should move correctly ..

carmila

hi, thanks for the replies. i make the path from combine the curves. my path is similarly like the leaf (the simple one), consists of 2 ellips curves. i already try to reduce the zone data (actually, i don't know to choose the correct zone). so, i try to use all of them. but the result is the same. the track of my robot is not the same with the path(more roughly).

i also found  that the time for 1x move along the path's simmulation  = 3,6s, but for 10x = 33,5 s, and for 20x = 66,8s. there's some reduction time .

can i make the movement's time is constant? because i have the project that make the robot always move (doesn't have a break time) and i should have the robot move preciciously.

thanks before

jerrico

you're right it's a little bit jerky .. but you could improve the accuracy .. by adding more path .. at least that's what i do .. to improve it .. 

 

carmila

thx jerrico.

do you mean 'adding more path' is to add more target in the path?

if yes, i already add some target, so i have many target. i hope with many target, my robot will move more accurate. but the result is the same. robot fail to reach several target, so the track of the robot's movement and the path is not the same.

when i see the true move video http://www.abb.com/product/seitp327/f0cec80774b0b3c9c1256fda 00409c2c.aspx, i wonder that the robot can move so smooth and accurate. is it because of the perfect path, only move 1x, or is it because the robot has break time to reach the home pose?

i also try to add the home pose , and add some delay before the program looping. it seems better than before, but there still has the reducing time. is there other opinion?

thx before

Henrik Berlin

Hi,

You should try to use "fine" or "z0" as your zonedata. When you use "fine" (stop point), the robot will stop at each point before proceeding to the next. When you use "z0" (fly-by point) the robot will pass through a zone of radius 0.3 mm surrounding the target before proceeding to the next point, it will not stop at the point.

Adding more points is not the solution to your problem, unless there are very large distances between the points. (I assume you use linear or circular motion, i.e. MoveL or MoveC and not MoveJ) The interpolator in the IRC5 controller will take care of this and internally add the required number of points to complete the motion to the desired accuracy.

If this does not help, you should ensure that the calibration parameters of your VC is nominal, i.e. you should not use the calibration data of your real robot. Doing so will cause the robot driven by the VC 0to miss the targets in RobotStudio, since it is robot model used for simulation is nominal, and the calibration parameters does only apply to the specific individual on your shop floor, i.e. not to the nominal robot in RobotStudio.

As for the simulation time, this might have two causes. First, the added time might be due to some initial start time of the controller. Secondly, you should be careful when interpreting the decimals of the cycle time. There are several sources of errors, primarily there will be a discretization error from the start and stop of the simulation. To reduce the influence of the error, I would recommend you to run the cycle a number of times, say ten, and divide the total time with the number of cycles, just as you did.

 

carmila

o... finally i find the problem!!!

thanks henrik, you're right. use the fine as zone data helps to make it more accurate, and the other solution is in the graphic and simmulation setting in tool-option menu.  i read it today in:

http://forums.robotstudio.com/forum_posts.asp?T ID=1956&PN=5

when i follow it, the simmulation become smoother.

so, it(the robot's track doesn't same with the path) is only on simmulation? if i download my current program in real robot, it will move correctly.am i correct?