Following Error of servo motor – (2) Eliminating method for Delta’s servo

Delta ASD-A2/M series servo’s following error comes from two parts:

  1. The delay of command processing Ed
  2. Servo control lag Es

The total following error:Etotal = Ed + Es

1. The reason for Ed is: the time delay of various filters and the delay of the command to take effect. The method of improvement is :

    • Set P1-36 =1, to enable command delay compensation.
    • Set P1-08 = 0, this filter is strictly prohibited !
    • Set P1-68 = 0~ 10 , this filter can be used moderately, not too much.

2. The reason for Es is : the error of the servo’s control loop, The solution is:

  • Set P2-53 = 20~ 40 to use the integrator of the position loop. The value should not be too large to avoid vibration.

The results of the positioning test after using the above settings are as follows: :

Taiwan ASD-A2 servo tracking error compensation oscilloscope observation

Delta’s ASD-A2 servo following error test – enable compensation

Compare the results with the experiments described in =>Servo Following Error -(1)Concept , and find out :

  • Error in constant speed operation: can be reduced to almost zero. If you think it is still not small enough, you can set P1-17= about 0.05 ms for further compensate !
  • The error of the acceleration/deceleration zone: it has been obviously reduced but it is impossible to become 0. If it is still not satisfactory, the feedforward gain P2-02 can be increased to improve it, but the disadvantage is that the vibration will be larger.

The functions described in this article are unique to Delta’s ASD-A2/ASD-M series of servos and supported in mode P1-01=1,B,C. Applications such as electronic cams for master/slave tracking can achieve very good results using the methods provided in this article!


 


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