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Improvement of Backdrivability of a Force-Controlled EHA by Introducing Bypass Flow Control

  • Jong-Hyeok Kim
  • Yeh-Sun HongEmail author
Regular Paper
  • 14 Downloads

Abstract

The dynamic response of an electro-hydrostatic actuator (EHA) is limited due to rotational inertia of its servomotor and pump. Thus, when an external disturbance with a high frequency is input to the force-controlled EHA, the pump speed may not be fast enough to attenuate the force control errors. In order to expedite the oil transfer between the cylinder chambers, a bypass valve was employed in this study. The bypass valve connecting both the cylinder chambers can then decompress the high-pressure chamber quickly by bypassing the oil to the low-pressure chamber to compensate for force control errors. To control the bypass flow without affecting the system stability, while the rotational velocity of pump was continuously varied by the force controller, a sliding mode control technique was applied. The sliding mode controller showed satisfactory control performance with respect to stability and robustness, in spite of highly nonlinear properties in the proposed system. Experimentally, where sinusoidal or stepwise velocity disturbance was exerted on the proposed EHA system with the force reference values set at 0 N or 200 N, the force control errors could be reduced markedly, compared to a conventional force-controlled EHA without bypass flow control. The performance improvement was more obvious when the sinusoidal excitation frequency increased from 1 to 3 Hz.

Keywords

Electro-hydrostatic actuator Force control Backdrivability Bypass flow control Sliding mode control 

Notes

Acknowledgement

This work was supported by a research program (Development of Hydraulic Robot Control Technology based on Accurate and Fast Force Control for Complex Tasks, No. 10047635) and funded by the Ministry of Trade, Industry & Energy (MI, Korea).

References

  1. 1.
    Lee, S. R., & Hong, Y. S. (2017). A dual EHA system for the improvement of position control performance via active load compensation. International Journal of Precision Engineering and Manufacturing,18(7), 937–944.CrossRefGoogle Scholar
  2. 2.
    Padovani, D., Ketelsen, S., Hagen, D., & Schmidt, L. (2019). A self-contained electro-hydraulic cylinder with passive load-holding capability. Energies,12(2), 292.CrossRefGoogle Scholar
  3. 3.
    Alfayad, S., Ouezdou, F. B., Namoun, F., & Gheng, G. (2011). High performance integrated electro-hydraulic actuator for robotics–Part I: Principle, prototype design and first experiments. Sensors and Actuators, A: Physical,169(1), 115–123.CrossRefGoogle Scholar
  4. 4.
    Kim, J. H., & Hong, Y. S. (2018). Robust internal-loop compensation of pump velocity controller for precise force control of an electro-hydrostatic actuator. Journal of Drive and Control,15(4), 55–60.Google Scholar
  5. 5.
    Jelali, M., & Kroll, A. (2012). Hydraulic servo-systems: Modelling, identification and control (pp. 32–34). Berlin: Springer.Google Scholar
  6. 6.
    Habibi, S., & Goldenberg, A. (1999). Design of a new high performance electrohydraulic actuator. In 1999 IEEE/ASME international conference on advanced intelligent mechatronics (Cat. No. 99TH8399) (pp. 227–232). IEEE.Google Scholar
  7. 7.
    Rongjie, K., Zongxia, J., Shaoping, W., & Lisha, C. (2009). Design and simulation of electro-hydrostatic actuator with a built-in power regulator. Chinese Journal of Aeronautics,22(6), 700–706.CrossRefGoogle Scholar
  8. 8.
    Has, Z., Rahmat, M. F. A., Husain, A. R., & Ahmad, M. N. (2015). Robust precision control for a class of electro-hydraulic actuator system based on disturbance observer. International Journal of Precision Engineering and Manufacturing,16(8), 1753–1760.CrossRefGoogle Scholar
  9. 9.
    Jovanovic, V., Djuric, A., Karanovic, V., & Stevanov, B. (2016). Applications of electro-hydraulics actuators. In SoutheastCon 2016 (pp. 1–5). IEEE.Google Scholar
  10. 10.
    Karanović, V., Jocanović, M., & Jovanović, V. (2014). Review of development stages in the conceptual design of an electro hydrostatic actuator for robotics. Acta Polytechnica Hungarica,11(5), 59–79.Google Scholar
  11. 11.
    Kaminaga, H., Tanaka, H., & Nakamura, Y. (2011). Mechanism and control of knee power augmenting device with backdrivable electro-hydrostatic actuator. In Proceedings of 13th world congress in mechanism and machine science (Vol. 12, p. 534).Google Scholar
  12. 12.
    Kaminaga, H., Amari, T., Katayama, Y., Ono, J., Shimoyama, Y., & Nakamura, Y. (2010). Backdrivability analysis of electro-hydrostatic actuator and series dissipative actuation model. In 2010 IEEE international conference on robotics and automation (pp. 4204–4211). IEEE.Google Scholar
  13. 13.
    Lee, W., Kim, M. J., & Chung, W. K. (2016). Joint torque servo control of electro-hydrostatic actuators for high torque-to-weight ratio robot control. In 2016 IEEE/RSJ international conference on intelligent robots and systems (IROS) (pp. 368–375). IEEE.Google Scholar
  14. 14.
    Lee, W., Kim, M. J., & Chung, W. K. (2017). Disturbance-observer-based PD control of electro-hydrostatically actuated flexible joint robots. In 2017 IEEE/RSJ international conference on intelligent robots and systems (IROS) (pp. 2821–2828). IEEE.Google Scholar
  15. 15.
    Alami, R., Albu-Schäffer, A., Bicchi, A., Bischoff, R., Chatila, R., De Luca, A., et al. (2006). Safe and dependable physical human-robot interaction in anthropic domains: State of the art and challenges. In 2006 IEEE/RSJ international conference on intelligent robots and systems (pp. 1–16). IEEE.Google Scholar
  16. 16.
    Boaventura, T., Semini, C., Buchli, J., Frigerio, M., Focchi, M., & Caldwell, D. G. (2012). Dynamic torque control of a hydraulic quadruped robot. In 2012 IEEE international conference on robotics and automation (pp. 1889–1894). IEEE.Google Scholar
  17. 17.
    Lee, W. Y., Kim, M. J., & Chung, W. K. (2015). An approach to development of electro hydrostatic actuator (EHA)-based robot joints. In 2015 IEEE international conference on industrial technology (ICIT) (pp. 99–106). IEEE.Google Scholar
  18. 18.
    Boaventura, T., Medrano-Cerda, G. A., Semini, C., Buchli, J., & Caldwell, D. G. (2013). Stability and performance of the compliance controller of the quadruped robot HyQ. In 2013 IEEE/RSJ international conference on intelligent robots and systems (pp. 1458–1464). IEEE.Google Scholar
  19. 19.
    Hiroshi, K., & Yoshihiko, N. (2013). Design of backdrivable mechanisms with electro-hydrostatic actuators. Retrieved June 12, 2019, from https://pdfs.semanticscholar.org/6198/6a2cee69b32a8d4a2379371ab235974275fc.pdf.
  20. 20.
    Zhihui, L. I., Shang, Y., Zongxia, J. I. A. O., Yan, L. I. N., Shuai, W. U., & Xiaobin, L. I. (2018). Analysis of the dynamic performance of an electro-hydrostatic actuator and improvement methods. Chinese Journal of Aeronautics,31(12), 2312–2320.CrossRefGoogle Scholar
  21. 21.
    Willkomm, J., Wahler, M., & Weber, J. (2014). Process-adapted control to maximize dynamics of speed-and displacement-variable pumps. In ASME/BATH 2014 symposium on fluid power and motion control (pp. V001T01A015–V001T01A015). American Society of Mechanical Engineers.Google Scholar
  22. 22.
    Shangguan, D., Chen, L., Ding, J., & Liu, Y. (2019). Modeling and simulation of dual redundant electro-hydrostatic actuation system with special focus on model architecting and multidisciplinary effects. In Proceedings of the 13th international modelica conference, Regensburg, Germany, March 4–6, 2019 (No. 157). Linköping University Electronic Press.Google Scholar
  23. 23.
    Muenchhof, M., Beck, M., & Isermann, R. (2009). Fault-tolerant actuators and drives—Structures, fault detection principles and applications. Annual Reviews in Control,33(2), 136–148.CrossRefGoogle Scholar
  24. 24.
    Shi, C., Wang, S., Wang, X., Wang, J., & Tomovic, M. M. (2017). Active fault-tolerant control of dissimilar redundant actuation system based on performance degradation reference models. Journal of the Franklin Institute,354(2), 1087–1108.MathSciNetCrossRefGoogle Scholar
  25. 25.
    Zhang, Q., & Li, B. (2011). Feedback linearization PID control for electro-hydrostatic actuator. In 2011 2nd international conference on artificial intelligence, management science and electronic commerce (AIMSEC) (pp. 358–361). IEEE.Google Scholar
  26. 26.
    Alle, N., Hiremath, S. S., Makaram, S., Subramaniam, K., & Talukdar, A. (2016). Review on electro hydrostatic actuator for flight control. International Journal of Fluid Power,17(2), 125–145.CrossRefGoogle Scholar
  27. 27.
    Hu, X. (2015). Electro-hydrostatic actuator (EHA) position tracking and correction (Doctoral dissertation).Google Scholar
  28. 28.
    Song, Y., Gadsden, S. A., El Delbari, S. A., & Habibi, S. R. (2012). System modelling and bulk modulus estimation of an electro hydrostatic actuator. In Bath/ASMe symposium on fluid power and motion control (FPMC).Google Scholar
  29. 29.
    Gadsden, S. A., McCullough, K., & Habibi, S. R. (2011). Fault detection and diagnosis of an electrohydrostatic actuator using a novel interacting multiple model approach. In Proceedings of the 2011 American control conference (pp. 1396–1401). IEEE.Google Scholar
  30. 30.
    Chen, H. M., Renn, J. C., & Su, J. P. (2005). Sliding mode control with varying boundary layers for an electro-hydraulic position servo system. The International Journal of Advanced Manufacturing Technology,26(1–2), 117–123.CrossRefGoogle Scholar
  31. 31.
    Guan, C., & Pan, S. (2008). Adaptive sliding mode control of electro-hydraulic system with nonlinear unknown parameters. Control Engineering Practice,16(11), 1275–1284.CrossRefGoogle Scholar
  32. 32.
    Eker, I. (2006). Sliding mode control with PID sliding surface and experimental application to an electromechanical plant. ISA Transactions,45(1), 109–118.CrossRefGoogle Scholar
  33. 33.
    Son, J. B., Seo, Y. S., & Lee, J. M. (2010). Design of SPMSM robust speed servo controller switching PD and sliding mode control strategies. Journal of Institute of Control, Robotics and Systems,16(3), 249–255.CrossRefGoogle Scholar
  34. 34.
    Khalil, H. K., & Grizzle, J. W. (2002). Nonlinear systems (Vol. 3). Upper Saddle River, NJ: Prentice hall.Google Scholar
  35. 35.
    Utkin, V., Guldner, J., & Shi, J. (1999). Sliding mode control in electromechanical systems. London: Taylor & Francis.Google Scholar
  36. 36.
    Slotine, J. J. E., & Li, W. (1991). Applied nonlinear control (Vol. 199). Englewood Cliffs, NJ: Prentice hall.zbMATHGoogle Scholar
  37. 37.
    Indrawanto, I. (2011). Sliding mode control of a single rigid hydraulically actuated manipulator. International Journal of Mechanical & Mechatronics Engineering, 11(5), 1–9.Google Scholar
  38. 38.
    Zhang, H., Liu, X., Wang, J., & Karimi, H. R. (2014). Robust H∞ sliding mode control with pole placement for a fluid power electrohydraulic actuator (EHA) system. The International Journal of Advanced Manufacturing Technology,73(5–8), 1095–1104.CrossRefGoogle Scholar
  39. 39.
    Wang, S., Habibi, S., Burton, R., & Sampson, E. (2006). Sliding mode control for a model of an electrohydraulic actuator system with discontinuous nonlinear friction. In 2006 American Control Conference (pp. 5897–5904). IEEE.Google Scholar
  40. 40.
    Boaventura, T., Focchi, M., Frigerio, M., Buchli, J., Semini, C., Medrano-Cerda, G. A., & Caldwell, D. G. (2012). On the role of load motion compensation in high-performance force control. In 2012 IEEE/RSJ International conference on intelligent robots and systems (pp. 4066-4071). IEEE.Google Scholar
  41. 41.
    Kim, J. H., & Hong, Y. S. (2017). Comparison of force control characteristics between double-rod and single-rod type electro-hydrostatic actuators (I): Tracking performance. Journal of Drive and Control,14(4), 9–16.Google Scholar
  42. 42.
    Rabie, M. G. (2009). Fluid power engineering/M Galal Rabie (pp. 289–291). New York: McGraw-Hill.Google Scholar
  43. 43.
    Yoo, S., Lee, J., Choi, J., Chung, G., & Chung, W. K. (2017). Development of rotary hydro-elastic actuator with robust internal-loop-compensator-based torque control and cross-parallel connection spring. Mechatronics,43, 112–123.CrossRefGoogle Scholar
  44. 44.
    Kim, J. H., & Hong, Y. S. (2017). Comparison of force control characteristics between double-rod and single-rod type electro-hydrostatic actuators (II): back-drivability. Journal of Drive and Control,14(4), 17–22.Google Scholar

Copyright information

© Korean Society for Precision Engineering 2020

Authors and Affiliations

  1. 1.Department of Aerospace and Mechanical EngineeringKorea Aerospace UniversityGoyang-siKorea

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