how to control parallax continuous rotation servo

[saifizi]

Dear all,

I'm using parallax continuous servo motor for my research project. I have one problem to solve. Now, I try to control the servo motor using labview interface with usb parallax servo controller. For this stage, I can interface the parallax continuous and 180 degree servo motor using labview 8.6 sucessfully but for I can't control position of\ parallax continuous servo motor. The servo motor move continouously when I giving signal to the servo controller using labview. For 180 degree parallax servo motor easyly to control using that's GUI programming.

Can you give me some sugestion to settle this problem. My member said that I need DAQ to give command to the continuous servo controller because the continuous servo controller become same with DC motor. I also want to know it's posibble to me not using microprocessor control the position of parallax servo motor. It's enough to me just using usb parallax servo controller to control the position of Continuous Parallax Servo. Or I need else things to program it? 

Thanks for your attention.

[jhsdelallana]

Hi saifizi,

This is the expected result.

The input of both motors are practically the same. This is the reason why your controller still works. The difference, naturally, would be the response. Applications using a continuous servo motor, usually, seeks to accurately control the rotational velocity and not the position. This is the reason why the motor runs continuously when activated (hence the name).

If you really need to control the position, my immediate suggestion would be to use another 180 degree servo motor. If using a continuous servo motor is paramount, an indirect method would be to manually compute for the position by integrating the velocity as a function of time. This would require some additional bit of programming, but shouldn't be that complicated.

Yes, it is possible to control the servo without the accompanying controller, but you would need a data acquisition hardware, plus time and expertise to code your own driver.

Best Regards,

Joshua de la Llana

Applications Engineer

NI ASEAN