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Repeat the test with different damping values according to the following guideline: 
Try using the largest damping factor value, which knocks out the resonance. Do not 
try using damping factors that are too small (0.07 is considered small) because too 
low a damping factor introduces more phase delay, and is less robust to resonant 
frequency variations

1

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 tuning from low-pass filter (section 

 

3.2.1). Going 

slow with the parameters we set will cause instability due to lack of information.  

A step response of 500 cnt/sec with the same parameters will look like this: 

 

                                                        

1

 The resonant frequency may change due to load or posture changes. 

20

 

Elmo

 

HARmonica Tuning Guide

 

HARTG0903

 

 

Содержание HARmonica

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

Страница 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...

Страница 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...

Страница 4: ......

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 9: ...5...

Страница 10: ...6 Elmo HARmonica Tuning Guide HARTG0903...

Страница 11: ...7...

Страница 12: ...8 Elmo HARmonica Tuning Guide HARTG0903...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 32: ...28 Elmo HARmonica Tuning Guide HARTG0903...

Страница 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...

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

Страница 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...

Страница 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...

Страница 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...

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

Страница 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...

Страница 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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