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Elmo HARmonica 

Hands-on Tuning Guide

 

 

 

 

 

 

 

September 2003

 

 

 
 

 

 

 

 

Summary of Contents for HARmonica

Page 1: ...Elmo HARmonica Hands on Tuning Guide September 2003...

Page 2: ...notice Information in this document is subject to change without notice Corporate and individual names and data used in examples herein are fictitious unless otherwise noted Doc no HARTG0903 Copyrigh...

Page 3: ...Step 2 2 3 1 3 The Auto tuning Procedure 3 3 2 Manually Tuning Velocity 3 3 2 1 Manual Tuning with a Low pass Filter 14 3 2 2 Manual Tuning of a PI Controller with a Notch Filter 17 3 3 Advanced Manu...

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Page 5: ...loop of the drive Current tuning is fully automatic The Composer creates a step command to the current loop and finds the optimum PI parameters according to step response iterations 3 Tuning Velocity...

Page 6: ...ile system Choose a value towards Slow and Stable if you need a more robust system which is required in a number of cases among them Machines whose mechanics may vary as when handling loads of differe...

Page 7: ...drive including sensors and delay influence 4 The tuner calculates the drive transfer function in order to control the system 5 The composer displays the step response of the control system 3 2 Manual...

Page 8: ...f machine vibrations are dangerous multiply KP by 1 5 each time instead of 2 9 Repeat step 8 until you reach one of the following The step response exhibits an overshoot of about 20 The step response...

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Page 13: ...Here we can see that we have reached a 25 overshoot and the beginning of oscillations 10 At this point reduce KP to 75 of its value and repeat the test 9...

Page 14: ...en reduced to 10 11 At this point we can add KI to the controller If one of the phenomena described in step 9 has returned revert to the previous value of KP 12 In order to set the first value of KI m...

Page 15: ...ine vibrations are dangerous set KI KP to 0 5 rise time and increase KI until an undershoot or oscillations occur 14 Set the KI value and repeat the test 15 We can see that the system has reached satu...

Page 16: ...0 000 We can see a large undershoot If a response such as this occurs reduce KI until you reach a satisfactory response 17 A robust system is required in a number of circumstances among them Machines...

Page 17: ...KP and run the test 18 Set the following parameters Rise time 0 0018 sec KI KP 1 Rise time 555 KI 80 555 44400 We can see we that the resulting settling time is 5 75 msec There is no reason to attemp...

Page 18: ...40 and KI 0 we can see high frequency vibrations in both the Velocity and Current command Adding a low pass filter with a high frequency will reduce the RMS noise of the current and will help us achie...

Page 19: ...Adding the low pass filter results in an overshoot at KP 80 A KP of 100 gives an overshoot of 20 and the beginning of oscillations 15...

Page 20: ...KP to 75 results in the following performance Rise time 0 002 sec results in KI KP 500 When adding a low pass filter do not set the KI KP higher than filter frequency 16 Elmo HARmonica Tuning Guide H...

Page 21: ...er is required and in which frequency it should be added Following is a characteristic example using the second resonant test system Start by designing a PI controller For KP we have the test results...

Page 22: ...e sec Figure 3 2 Zoom of current test measurement for measuring expected plant resonance RSpeed2 Now add a notch at frequency 359 with a damping of 0 07 Click the Designer button in the Advanced Filte...

Page 23: ...Zoom of current test measurement for the same controller used in Figure 3 2 with notch Figure 3 4 reveals two remaining oscillations one about 75 Hz and the other 860 Hz The oscillation at 75 Hz is d...

Page 24: ...st to resonant frequency variations1 Continue the PI manual tuning process for designing KI and KP as described in the previous section 3 3 Advanced Manual Tuning For this procedure we will use the tu...

Page 25: ...t low speeds We can see that the KI KP factor is higher at low speed in order to overcome friction Advanced manual tuning is very similar to manual tuning The advance manual tuning dialog box provides...

Page 26: ...arked row 3 Check the Accept check box of the row after you have received acceptable parameters There is no need to tune all the available velocities in the table Choosing three or four velocities to...

Page 27: ...for the steady state velocity In our case we saw that KP 20 and KI 15000 gave us satisfactory performance 8 Check the Accept check box on the 505 cnt sec row and proceed to the next speed 9 Select 240...

Page 28: ...e results will be 10 After setting acceptable parameters for each tuned speed and checking Accept in that row click Interpolate and then check Gain Scheduling ON 24 Elmo HARmonica Tuning Guide HARTG09...

Page 29: ...elocity loop resulted in a position controller equivalent to a PID controller with KIPID 0 KPPID KIspeed KDPID KPspeed Pos Speed I P I Pos Speed Speed P P P I Speed D P K K K PID K K K K PIP K K Runni...

Page 30: ...hows that the position loop is closed without closing the position constant error 4 2 Tuning the Position Loop 1 Reduce the velocity KI by half and set a step in velocity 26 Elmo HARmonica Tuning Guid...

Page 31: ...t position KPposition 0 5 rise time This will give a position bandwidth that equals the velocity bandwidth divided by 4 In this case KPposition 0 5 0 0018 280 This results in the following performance...

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Page 33: ...ay 1 Position Error Display 2 Velocity Velocity command Display 3 Current command 5 Set the Trigger Mode to Auto the Source to Begin Motion and the Delay to 10 Set the Resolution to 0 36 msec 6 In the...

Page 34: ...8 Start the recorder and press Run Test The following graph will be displayed 30 Elmo HARmonica Tuning Guide HARTG0903...

Page 35: ...uter loop parameter KP The iteration range for the KI of the inner loop should not exceed 50 of its original value and the iteration on the outer loop should not exceed 100 of its original value Incre...

Page 36: ...tem vibrates at low and zero speeds This is due to a delay in the information caused by the sensor at low speed The velocity loop should not be closed at a bandwidth greater than V 10 1000 cnt sec wil...

Page 37: ...nt sec row in the table 3 Set several speed parameters according to the rule described before and check each relevant Accept check box Set the following rows 694 cnt sec Position KP 700 5 140 280 140...

Page 38: ...1000 cnt sec 7 5 RPM 500 cnt sec 3 75 RPM 34 Elmo HARmonica Tuning Guide HARTG0903...

Page 39: ...Tuning dialog box In order to make the system more rigid you can increase the GS 10 parameter In order to make the system more stable at low speeds and at no speed reduce GS 10 The Composer sets a de...

Page 40: ...low a value for GS 10 gives a poor response to external disturbance Remember to save your application after tuning with the Advanced Manual Tuning option The application is not saved automatically on...

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