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Measurements on the Thunder TH-6R actuator

Buhl, Thomas; Gaunaa, Mac; Bak, Christian; Hansen, P.; Clemmensen, K.

Publication date:2005

Document VersionPublisher's PDF, also known as Version of record

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Citation (APA):Buhl, T., Gaunaa, M., Bak, C., Hansen, P., & Clemmensen, K. (2005). Measurements on the Thunder TH-6Ractuator. (Denmark. Forskningscenter Risoe. Risoe-R; No. 1537(EN)).

Risø-R-1537(EN)

Measurements on the Thunder TH-6R actuator

Thomas Buhl, Mac Gaunaa, Christian Bak, Per Hansen, Kasper Clemmensen

Risø National Laboratory Roskilde Denmark

November 2005

Author: Thomas Buhl, Mac Gaunaa, Christian Bak, Per Hansen, Kasper Clemmensen Title: Measurements on the Thunder TH-6R actuator Department: Wind Energy Department

Risø-R-1537(EN) November 2005

ISSN 0106-2840 ISBN 87-550-3480-2

Contract no.:

Group's own reg. no.: (Føniks PSP-element)

Sponsorship:

Cover :

Pages: 20 Tables: 2 References: 2

Abstract (max. 2000 char.): This report is a collection of the measurements carried out on the TH-6R actuator from Face International Co. The work is a part of the ADAPWING project, which aims at developing a method to alleviate some of the fluctuating response of a wind turbine by using adaptive trailing edge geometry. The ultimate goal of the project is to make a prototype and test this in a wind tunnel. First step is to clarify whether the actuator can be use for this purpose. The report will include: static and dynamic test of the actuator, test in different ranges of its operational range and comparison of two actuators. One of the important fact that is discovered is that the actuator response has a clear hysteresis loop. This fact must be taken into account when using the actuator as trailing edge geometry on the wind turbine wing.

Risø National Laboratory Information Service Department P.O.Box 49 DK-4000 Roskilde Denmark Telephone +45 46774004 bibl@risoe.dkFax +45 46774013 www.risoe.dk

Ris�{R{1537Measurements on the Thun-der TH-6R a tuatorThomas Buhl, Ma Gaunaa, Christian Bak,Per Hansen, Kasper Clemmensen

Ris� National Laboratory, Roskilde, DenmarkNovember 2005

Abstra t This report is a olle tion of the measurements arried out on the TH-6R a tuator from Fa e International Co. The work is a part of the ADAPWINGproje t, whi h aims at developing a method to alleviate some of the u tuatingresponse of a wind turbine by using adaptive trailing edge geometry. The ultimategoal of the proje t is to make a prototype and test this in a wind tunnel. Firststep is to larify wether the a tuator an be use for this purpose.The report will in lude; stati and dynami test of the a tuator, test in di�erentranges of its operational range and omparison of two a tuators.One of the important fa t that is dis overed is that the a tuator response has a lear hysteresis loop. This fa t must be take into a ount when using the a tuatoras a trailing edge geometry on the wind turbine wing.

Print: Pitney Bowes Management Servi es Denmark A/S, 2005

Contents1 Introdu tion 42 Test stand 53 TH-6R data sheet 74 Measurements 84.1 Stati test 84.2 Full peak-to-peak (-450 to 900 V) at 0.45 Hz 84.3 Mixed signal at 0.45 Hz 94.4 500 to 900 V at 0.45, 1 and 5 Hz 134.5 Di�erent intervals at 0.45 Hz 144.6 A tuator omparison 155 Con lusions 18

Ris�{R{1537 3

1 Introdu tionIn this report a measurement study of the a tuator TH-6R from Fa e Interna-tional Corporation [1℄ is des ribed. This work is part of the proje t ADAPWING arried out at Ris� National Laboratory partly funded by the Danish Resear hCoun il. The ADAPWING proje t aims at developing a method to alleviate someof the u tuating response of a wind turbine by using Adaptive Trailing EdgeGeometry (ATEG). Di�erent ATEG designs has been investigated, however, themost suitable found was the TH-6R a tuator manufa tured by Fa e InternationalCo.The proje t does not aim at making a system that an be sold to the windturbine manufa tures, but instead developing a prototype that an be tested in awind tunnel and hen e demonstrate the potential shown in earlier work [2℄. Thegoal of this report is therefore not to investigate wether this a tuator an be use ina losed loop ontroller system, but rather to un over the potential of the a tuatorin a test environment.Three major questions must be answered in this report to on lude wether thementioned a tuator is usable for this appli ation.� Stati loading response.� Dynami response.� Reprodu ibility of response for di�erent a tuators of same kindThe stati loading response is important sin e the aerodynami loading of thetrailing edge will be non-zero and hange with angle of atta k and ap de e tion.It is important to estimate how mu h de e tion the aerodynami loading ausessin e there will be no feedba k ontrol loop in the wind tunnel tests.The dynami response will be used to estimate the response of the a tuatorfor intermediate u tuations. It will provide results that an be used to estimateerrors and lags in the a tuators.In the wind tunnel test the pro�le will be a 2 meter se tion with a tuatorsalong the full width of the pro�le demanding about 40 a tuators. It is thereforeimportant to investigate if the output response of one a tuator is equal to that ofanother a tuator or estimate the margin of error.

4 Ris�{R{1537

2 Test standThe a tuator is fabri ated su h that it an either be lamped or a t as a antileverbeam supported at one end. For the purpose of an ATEG, the a tuator will bea ting as a antilever beam, hen e the test is rigged as shown in Figure 1.The a tuator is �tted with two strain gauges as seen in Figure 2; one at theroot and one at the middle. Furthermore, a laser distan e measurement devi e issetup to give an indi ation of the real displa ement.

Figure 1. A pi ture of the test stand with the laser distan e measuring devi e.

Figure 2. A pi ture of how the strain gauges are �tted the TH-6R a tuator.Ris�{R{1537 5

Figure 3. A pi ture of the ampli�er use in the tests.

6 Ris�{R{1537

3 TH-6R data sheetFa e International Co. produ es a number of di�erent a tuators in various sizesof with di�erent response. For the test in the wind tunnel the airfoil se tion willbe a 2 meter se tion with a hord of 60 m. Earlier work show that a trailing edge ap of 10% of the hord length is suÆ ient to get a for e response large enoughwithout having a too large ap displa ement. This result in an a tuator with alength of about 6 m. The TH-6R a tuator is shown in Figure 4 and the propertiesare shown in Table 1 and Table 2.Mass 16.3 gFootprint (domed) 75.82 mm x 51.82 mmFootprint ( at) 76.20 mm x 51.82 mmPiezo Thi kness 0.38 mmTotal Thi kness 0.71 mmDome Height 4.24 mmCapa itan e 77 nFTable 1. TH-6R Dimensions and Physi al Properties.Max. Voltage- +450V 900VTable 2. TH-6R Spe i� ations: Ele tri al Properties.

Figure 4. A pi ture of the TH-6R a tuator.

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4 MeasurementsIn this se tion the most important results from the tests are shown and om-mented. The tests hosen are sele ted to get the best overview of the response ofthe a tuator in di�erent on�gurations.4.1 Stati testFor the purpose of an ATEG the a tuator needs to have a ertain sti�ness to arry the aerodynami for es on the trailing edge of the airfoil. These for es areestimated using a atta hed ow ode and for worst ase s enario orrespondingto a ase where the angle of atta k is 10 degrees and the angle of the ap is10 degrees. Figure 5 shows the for es on the ATEG. Converting this distributedaerodynami for e to a single load su h that it an be tested in the test standresults in a 50 g mass at the end of the a tuator. The 50 g gives a displa ementof 1.4 mm whi h is equivalent to about 1.4 degrees. This error must be taken intoa ount in the wind tunnel tests. This is one of the reasons for the strain gaugeswhi h will be used as a he k.4.2 Full peak-to-peak (-450 to 900 V) at 0.45 HzIn this se tion the a tuator is tested in its full range. The peak-to-peak voltagevalues are from -450 V to 900 V. This is tested at 0.45 Hz in 600 s.In Figure 6 the displa ement of the a tuator at 54 mm is shown as a fun tion ofthe voltages applied to the a tuator. It an be seen that there are some hysteresisin the a tuator, as the response is a loop.In Figure 7 a small se tion of the time series is shown for the voltage anddispla ement response. The red urve is the input voltage to the a tuator whilethe blue urve is the laser measured displa ement. It an be seen that there isa phase di�eren e between the input voltage and the displa ement output. Thephase di�eren e is larger for intermediate voltage and be ome less at the peaks.This fa t ould also be seen in Figure 11 where the loop is a ellipse with "sharp

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Figure 7. Voltage on y1 axis and displa ement on y2 axis as a fun tion of time.ends". The more open the loop is the bigger the phase di�eren e is.4.3 Mixed signal at 0.45 HzIn this next test the input signal varied as follows: Full peak-to-peak the �rst 3minutes, 400 V to 900 V the next 3 minutes, -450 V to 50 V next 3 minutes andthe full peak-to-peak the last minute of the 10 minutes time series. This inputsignal is shown in Figure 10.Ris�{R{1537 9

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time [s]Figure 9. Amps as a fun tion of time.In Figure 11 the displa ement is shown as a fun tion of the input voltage. Similarloop as seen in the previous test is seen.The orresponding laser displa ement output signal is shown in Figure 12 as afun tion of time. The full peak-to-peak input results in a displa ement as expe tedfrom the previous test. For the next 3 minutes with 400 V to 900 V input a slightin rease in the maximum output displa ement of about 0.3 mm is seen, whi h isunexpe ted. The displa ement amplitude is un hanged.In the next 3 minute series with input voltage of -450 V to 50 V an ever worse10 Ris�{R{1537

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time [s]Figure 13. Displa ement as a fun tion of time for the signal -450 V to 50 V.The displa ement response for the se ond a tuator is shown in Figure 14. The samebehavior is not seen. The amplitude of the out de reases like in the last test asseen in Figure 15, however, after about 20 se onds the amplitude stabilizes at agiven interval for a period of about 3 minutes as seen in Figure 16. After thisperiod the amplitude again de reases (as seen in Figure 17) to settle at a onstantlevel for the rest of the time series. This rather unpredi table behavior will resultin a modi�ed range of usage.12 Ris�{R{1537

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Figure 14. Displa ement as a fun tion of time.

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Figure 15. Displa ement and voltage as a fun tion of time in the period from 0 to20 se onds.4.4 500 to 900 V at 0.45, 1 and 5 HzIn this se tion the a tuator is tested in an upper voltage range from 500 to 900 volt.In Figure 19 the displa ement is shown as fun tion of the input voltage for 0.45,1 and 5 Hz. The level of displa ement and the amplitude is within an a eptablerange of error. The reason for the smoother urve at 5 Hz is that all the urveswere done for the same sample frequen y.Ris�{R{1537 13

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Figure 16. Displa ement and voltage as a fun tion of time in the time period from20 to 60 se onds.

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Figure 17. Displa ement and voltage as a fun tion of time in the period from 160the 240 se onds.4.5 Di�erent intervals at 0.45 HzIn this se tion the following intervals are tested; -450 to -50V, -200 to 200V, 200 to600V and 500 to 900V. The resulting responses an be seen in Figure 20. As justdis ussed the a tuator response for the ranges where there are negative voltagesare unpredi table. The high voltage range series are as expe ted. The hysteresisloops are small for the highest ranges while the response for the series 200 to 600Vhas more hysteresis. These results are as expe ted from the peak-to-peak results.14 Ris�{R{1537

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Figure 19. Displa ement as a fun tion of a tuator input voltage for di�erent inputfrequen ies.4.6 A tuator omparisonThe wind tunnel test se tion is a nearly 2 meter se tion and the a tuators areabout 52 mm wide, hen e, a number of (about 40) a tuators must be �tted tothe pro�le se tion and they must work together giving the same response. In thisse tion to di�erent a tuators (of the same kind) are tested.In Figure 22 a omparison of the voltage-displa ement response is shown forthe two a tuators. The green urve is a tuator 2 and it an be seen that theRis�{R{1537 15

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Figure 21. Amps as a fun tion of time.amplitude of a tuator 2 is about 0.6 mm larger than that of a tuator 1. Thehysteresis opening is also larger for a tuator 2.From this it an be on luded that it is ne essary for the wind tunnel test toinsure that all 40 a tuators are giving the same response. This will be for ed beatta hing a metal guidan e rod that will overlap all a tuators.16 Ris�{R{1537

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Figure 22. Displa ement as a fun tion of a tuator input voltage.

Ris�{R{1537 17

5 Con lusionsIn this report a measurement study of the TH-6R a tuator from Fa e InternationalCo. The a tuator will be used as a Adaptive Trailing Edge Geometry (ATEG) ina wind tunnel test to illustrate and verify the potential of using an ATEG toalleviate u tuating loads on a wind turbine.The results showed that using the a tuator in the negative voltage range anresult in unpredi table output response. Hen e it should be avoided in the windtunnel test. Using the negative range should only be when using the a tuator inpeak-to-peak situations (from -450 to +900V).Furthermore, it was seen that the reprodu ibility of the output response fromtwo di�erent a tuators of the same kind is marginal. There was an error of about0.6 mm from two di�erent a tuators. It is therefore imperative that the a tuatorswill be for ed to give the same response in the wind tunnel test.

18 Ris�{R{1537

Referen es[1℄ www.fa e o. om.[2℄ Buhl, T., Gaunaa, M., and Bak, C., \Potential Load Redu tion Using Airfoilswith Variable Trailing Edge Geometry," Journal of Solar Energy Engineering ,Vol. 127, 2005, pp. 503{516.

Ris�{R{1537 19

Mission

To promote an innovative and environmentally sustainable technological development within the areas of energy, industrial technology and bioproduction through research, innovation and advisory services.

Vision

Risø’s research shall extend the boundaries for the understanding of nature’s processes and interactions right down to the molecular nanoscale.

The results obtained shall set new trends for the development of sustainable technologies within the fields of energy, industrial technology and biotechnology.

The efforts made shall benefit Danish society and lead to the development of new multi-billion industries.

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