Servomotor

[Alex S.A]

Hi..iam here again with a new problem at servomotor. Now It is jump along all the rail. I checked the mechanical system. It is like cogged toothed and rail.
It is accomplish correctlly. I got a similar problem once but the equipment gotta two servomotor and the problem was that the parameters of encoder were differents at X axis,now I have just one servomotor but the problem is alike. The servor driver is from Axor. There is at the moptor a box gear, I moved the motor not accomplished and it did not show problem, just when I accomplish it. If someone has any tip please post it....
Thanks
Alex S.A
Help me !!!!!!!!!!!

[Al_The_Man]

Originally Posted by Alex S.A There is at the moptor a box gear, I moved the motor not accomplished and it did not show problem, just when I accomplish it. Alex S.A

Alex, I think you will have to defiine what you mean by accomplish? Did you try dis-engaging the spur gear from the rack? and see what the result is?
Al

[ESjaavik]

I think you should say some more about what you mean by "jump all along the rail". By what I understand from what you're writing, it seems there may be dirt in the rack. Then it will bind, and jump up as it hits the debris (if the rail guide allows such movements).

[ynneb]

Alex, I am guessing that you mean by "jumps along the rail" that the servo is constantly trying to correct itself. Is it vibrating? If this is the case it may be an idea to tune your servo driver card. Does your driver card have trim pots that you can adjust?

[Alex S.A]

Originally Posted by ynneb Alex, I am guessing that you mean by "jumps along the rail" that the servo is constantly trying to correct itself. Is it vibrating? If this is the case it may be an idea to tune your servo driver card. Does your driver card have trim pots that you can adjust?

I think so that is what you said but what I think strange is : there is just one servormotor. I got a such problem and the encoder servomotors in longitudinal rail's parameters were differents , when they should be the same value. Now there is one motor and this is happening. Do you think that this problem can happen in this conditions? Why?
The machine cut sheet and the measurements of the parts cut are the same as set before.
So that I think that the enconder is not the problem...

[Alex S.A]

just more one thing..the motor is not vibrating

[Al_The_Man]

I get the impression that you used to have 2 motors controlling one of the axis on this machine? and now you just have the one , is this correct? If you have modified the configuration from a double motor axis to a single it will depend on how the axis were synchronised in the controller. For example, Galil and Acroloop controllers have a command such as axis lock or a way of synchronising each motor, so if you have modified the machine you may have upset this synchronisation. What controller is on this Machine? is it a PC based control?
Al

[Alex S.A]

Originally Posted by Al_The_Man I get the impression that you used to have 2 motors controlling one of the axis on this machine? and now you just have the one , is this correct? If you have modified the configuration from a double motor axis to a single it will depend on how the axis were synchronised in the controller. For example, Galil and Acroloop controllers have a command such as axis lock or a way of synchronising each motor, so if you have modified the machine you may have upset this synchronisation. What controller is on this Machine? is it a PC based control? Al

Since the first thread I said that there is just one motor. I did not change the machine. It is its original configuration. The controler is a CNC model ANC 401 and the driver is from Axor. That configuration is not necessary synchronism right? If so, what do I have to do?
thanks Al,
Alex S.A

[Al_The_Man]

OK I think I am getting the picture, first off, on a large gantry machine (12'x8' and up table). It is usuall to have either an axis motor on either side of the x travel, or a shaft or means of a coupling from one side to the other or some method to keep both sides tracking parallel. check this out if the machine has it.
Most table are built with a compliant side and a non-compliant side, that is there is one side with something like a linear bearing as well as the rack to stop the gantry from moving sideways.
The first think I would do is to try and eliminate mechanical problem first, dis-engage the x axis drive (spur gear from the rack etc) and make sure the gantry moves by hand all the way along the track, while the axis is disconnected use the control to rotate the motor at different feed rates and check for erratic rotation etc. If all checks out ok , then I would perform an alignment of the drive, if it is a DC drive with tach feedback, I would perform the alignment by disconnecting the analogue input signal and provide a separate 0v to +-10 volts variable supply to the analogue input for alignment purposes, ( I have made myself a battery box with a 5k potentiometer and two 9v batteries).
This allows control of the x axis without the need for the CNC controller and tests the motor and drive amplifier.
If after all this you still have a problem, I would consider that there may be a problem with encoder or controller motor tuning parameter.
Al

[Alex S.A]

Thanks for all suggestion .. I found the problem.. The tooth of the piece that is on the motor axis and make compliance with the rail ( i forgot the name ) ...
thanks for all help

[Billhill]

I think you mean the pinion gear had a broken tooth?