2Set the Speed controller gain to 0. 1(P1460) and int Set the Speed controller gain to 0.1(P1460) and int. time to 100msec (P1462). Now select measuring Function 1 from the drop Down ChoiceStart with the first Measuring function from the drop down list. This function is used to locate the frequency of the Current set point bandwidth filter.The axis will travel in the positive direction with readings started after the offset. Reduce the travel with a lower Measuring periods.
3Start the axis and then Run Trace and use X Cursor to find Frequency of 1st Pole
5Open Current Setpoint Filter and use Previous value for Notch Frequency.
6Use this Measuring Function Choice for Next Step Select the last Measuring function from the drop down list. This function is used to optimize the Current Controller P Gain (p1715) and reset (p1717) parameters.
7Start the axis and Measuring function again . Now adjust the Current controller gain and Int. times to achieve the desired responseP1715 = gain P1717 = int. time.
8Note the default value for the gain and integration time
19Adjust Kp and Tn for Desired Results Speed Controller settings this example:P gain p1460 = Nms/radReset time p1462 = 50 msSpeed controller optimized, and torque limit not exceeded
20Closed Speed Controller Measuring Function – Frequency Domain This is an optional step to ensure the Kp value derived above does not produce a bode diagram that raises above the 0db line.Select the first Measuring function from the drop down list. This function is used to optimize the Speed Controller parameters in the Frequency Domain.
21Only P- controlled Kp = p1460 Nms/rad Measurement of Closed Speed Controller – Bode Diagram – Frequency DomainOnly P- controlled Kp = p1460 Nms/radKp=0.04 Nms/rad, Kp=0.1 Nms/rad, Kp=0.2 Nms/rad, Tn =1000 msRed: Peak above 0 dB Controller can start oscillating!Higher Kp gain increases the band width of the controller
22Comparison of Time Domain and Frequency Domain Kp=0.04 Nms/rad, Kp=0.1 Nms/rad, Kp=0.2 Nms/rad, Tn =1000 msHigher Kp gain increases the band width of the controller shorter rise time (see step response)
23The Reference model can be used to dampen the initial overshoot with an aggressive Kp setting. Red: Kp = 0.15 Nms/rad, Tn 6 ms, fref = 250 Hz, D = 0.707Green: Kp = 0.15 Nms/rad, Tn 6 ms ,fref = 60 Hz, D = 0.707Blue: Kp = 0.15 Nms/rad, Tn 6 ms, fref = 130 Hz, D = 0.707Reference model too small fref = 60 Hz
24Closed Position Controller - Axis Position Tuning Step 1: Switch on the speed additional set-point from the axis System variableAxis.servosettings.additionalcommandvalueswitch = YESCAUTION: Remember to deactivate this setting upon completion of the position tuning.Step 2: Setup a temporary program to enable the axis to allow the function generator to enable movement of the axis.
25Step 3: Open the expert list and initialize the PV_Controller variables shown below. Open the Expert list of the Axis for balanceFilterMode, kpc, and preConTypeOfAxis.NumberOfDataSets.ControllerStruct.PV_Controller.balanceFilterMode1Select the entries as shown above in the Next value column.Switch the expert list to the “System variables” tab.Select the restartactivation entry as “activate_restart”. Click back on the “Configuration data” tab to have the entries accepted into the Current value. See the next slide for the result.23
26Step 3: The values from previous slide are now in the current value column Step 4: Initialize DynamicData with zero values for positionTimeConstant, torqueTimeConstant, and velocityTimeConstant.
27Step 5: Configure the function generator to the Signal Name: Triangular with a carefully selected Amplitude and PeriodAdjust the Amplitude to limit the travel of the oscillating axis.
28Adjust the Positioning window and the Standstill window to prevent function from Generating a Standstill error. Rotary axis will be in degrees.
29Step 6: Configure a trace with the axis data as shown below.
30Step 6: Run the initial trace and note the Following error readings. Kpc = 0.0 %Kv = 10, Following error 0.4
31Step 7: Optimize the performance by setting Kpc Weighting factor of the precontrol to 100% Kv = 10, Following error 0.016
32Step 8: Continue to optimize the performance with adjustments to the Kv value. Kpc = %Kv = 40, Following error 0.016
34Kpc = %Kv = 200, Following error Axis movement may be to stiff for mechanical connections with this Kv
35This trace shows the same Position tuning values with the period decreased to 800 ms. The overall spike in the following error can be reduced with adjustments to Kpc, though; this introduces a greater average following error.Kpc = %Kv = 200, Following error Axis movement may be to stiff for mechanical connections with this Kv
36Important parameters for the tuning in Simotion • Cycle time DP-, Servo- and IPO-cycle time• DSC needed Telegram 105• Kv position controller-amplification• Kpc Pre-control• FIPO Fine interpolation type• VelocityTimeConstant (vTc) Symmetry filter time constant (PT1-Glied)• PositionTimeConstant (pTc) Position extrapolation time