Esnek-mafsallı robot kolun yüksek dereceli kayma kipli kontrolu

Ucunda yük bulunan bir Esnek-Mafsallı Robot Kol (EMRK) hareket kontrolu için Kayma Kipli Kontrol (KKK) ve Yüksek Dereceli Kayma Kipli Kontrol (YDKKK) yöntemleri uygulanmıştır. Esnek kolun istenen bir noktada konumlandırma ve yörünge izleme kontrolu için KKK ve 2nci dereceden YDKKK (2-YDKKK) yöntemleri kullanılarak kontrol algoritmaları türetilmiştir. 1-SD (Serbestlik Dereceli) esnek mafsallı robot kolun hassas hareket kontrolu problemi, özellikle hafif ve esnek yapısı ile matematiksel modelinde yer alan şekil kipleri dikkate alındığında; aşırı doğrusal olmayan ve ayrışmayan dinamik denklemleri ile kontrol alanında oldukça zorlayıcı bir çalışma konusudur. Doğrudan Tahrikli (DT) eklem motoruna sahip EMRK çalışma esnasında oluşan esneme, titreşimler ve farklı kütlelere sahip uç yükü ile birlikte hareket kontrolunun sadece eklem motoruna uygulanabilen kontrol işareti ile sağlandığı düşünülürse yüksek performanslı kontrolör gerektirdiği açıktır. Dayanıklı kontrol yöntemlerinden, sistem belirsizliklerine karşı etkili ve sistem parametre değişimlerinden bağımsız olan KKK yöntemi kullanılmıştır. Yöntemin olumsuzluğu olan çatırtı problemi ise 2-YDKKK yöntemi ile türetilen kontrolör ile giderilmeye çalışılmıştır. Her iki yöntemin deneysel olarak karşılaştırılması ve kontrolörlerin gerçeklenmesi bir Donanımlı Simülatör (Dsim) kullanılarak yapılmıştır. Donanımlı simülatör donanım ve yazılıma sahiptir. Dsim de bulunan donanımlar gerçek sistemin önemli bölümlerini içerir. Bu nedenle doğrudan tahrikli iki motor Dsim de yer almaktadır ve millerinden birbirine akuple bağlanmışlardır. Bu sistemle yapılan deneysel çalışmalara göre 2-YDKKK yönteminin KKK yöntemine göre EMRK hareket kontrolunda daha etkili olduğu görülmüştür. Kontrolörlerin doğrudan tahrikli motor moment salınımlarını bastırmadaki etkinliği harmonik analizi ile karşılaştırılmıştır.

High order sliding mode control of a flexible-link robot arm

In this study, Sliding Mode Control (SMC) and High Order Sliding Mode Control (HOSMC) methods are applied to a single Flexible Link Robot Arm (FLA) with payload. A sliding mode and high order sliding mode controllers are designed to achieve set point precision positioning control and trajectory tracking control for a FLA. Flexible robot arms have structural flexibilities and resulting high number of passive degrees-of-freedom. They cannot be decoupled due to the highly nonlinear structure. Since the flexible systems have highly nonlinear structure and coupled dynamics, the sliding mode based control approach is chosen a powerful method to overcome the unmodeled and parametric uncertainties. One of the proposed controllers is 2nd order HOSMC method is compared with classical SMC method. Comparison of the methods is experimentally fulfilled using HIL simulator, and additionally torque ripple analysis is made to evaluate of the methods aspect from system harmonics. Direct drive motors are used as actuator in controlled systems. Of all system dynamics affect system harmonics via motor shaft due to the direct drive system that is no gear box. Therefore, harmonics analysis is crucial to investigate of designed controllers effects on system harmonics. To precise set-point and trajectory tracking control of 1-DOF DD FLA has been derived SMC and HOSMC. Sliding Mode Controllers (SMCs) have the robustness properties, while also increasing accuracy by reducing chattering effects. The performance of the designed control methods are tested for the precise position and targeting control of a 1- DOF-DD-FLA system under heavy uncertainties. Comparative results of both methods have been evaluated in real-time using a Hardware-in-the- Loop (HIL) simulator designed for robotics. Especially, HIL simulator for this system includes DD motors and obtained results can be evaluated more realistically according to pure computer simulations. Additionally, torque ripples of whole system with HIL simulator have been determined and their eliminations using for both methods are introduced. HIL simulator is used to implement designed controller for a flexible-link arm. Direct drive joint motors are important parts of the direct drive underactuated robot manipulators. Therefore two DD motors take part in HIL simulator and couple through their shaft. One of the motors represents joint actuator, while the other motor is used for generation of the dynamics of the controlled system via the torque applied to the shaft. The two motors acting as “actuator” and “load torque simulator” are driven separately by a high performance controller board. HIL Simulator is expressed briefly as software that is modeled control algorithm and system dynamic model via controller board is integrated with hardware. HIL simulation differs from computer simulation as it involves actual hardware and is not limited with a software-based representation of the system. Main aim is to use HIL Simulator is able to make more realistic analysis about behaviors of the system dynamics in real-time. It is over computer simulation since the simulator incorporates some of the crucial hardware of the actual system that takes part in the loop. For this purpose defined HIL simulation environment is useful to test, analysis and performance evaluation of designed controllers for underactuated robot manipulators. The major contribution of this study is experimental evaluation of 2nd order HOSM controller and SMC for tracking accuracy and robustness against internal and external uncertainties of DD flexible-link arm with the consideration of the full system dynamics effects. The HIL experimental results confirm and depict that the 2-HOSMC method has robust and accurate performance as expected from the HOSM controllers. Additionally, torque ripples of whole system with HIL simulator have been determined and their eliminations using for both methods are introduced. According to the HIL experimental results and torque ripple analysis, using 2-HOSMC has advantages an increased accuracy over the SMC.

___

  • Eason, G., Noble, B. ve I. Sneddon, N., (1955). On certain integrals of Lipschitz-Hankel type involving products of Bessel functions, Philosophical Transaction of the Royal Society, London, A247, April, 529-551.
  • Spong, M.W., (1994). Partial feedback linearization of underactuated mechanical systems, IROS’94, Munich, Germany, 314-321, September.
  • Spong, M.W., (1995). The swing up control problem for the Acrobot, Control Systems Magazine, IEEE, 15, 1, February, 49-55.
  • Geniele, H., Patel, R.V. ve Khorasani, K., (1997). End-point control of a flexible-link manipulator: An experimental study, IEEE Transaction Control System Technology, 5, November, 556-570.
  • Tso, S.K., Yang, T.W., Xu, W.L. ve Sun, Z.Q., (2003). Vibration control for a flexible-link robot arm with deflection feedback, International Journal of Non-Linear Mechanics, 38, 51-62.
  • Sciliano, B. ve Book, W., (1989). A singular perturbation approach to control of lightweight flexible manipulator, International Journal of Robot, 7, 4, 79-89.
  • Khorrami, F., Jain, S. ve Tzes, A., (1995). Experimental results on adaptive nonlinear control and input pre-shaping for multi-link flexible manipulators, Automatica, 31, 1, 83-97,.
  • Yang, J.H., Lian F.L. ve Fu L. C., (1997). Nonlinear adaptive control for flexible link manipulators, IEEE Transaction on Robotics and Automation, 13, February, 1.
  • Yang, H., Krishnan, H. ve M.H. Ang, (1999). Tiptrajectory tracking control of single link flexible robots via output redefinition, Proceedings of IEEE International Conference on Robotics and Automation, 1002-1107.
  • Dogan, M., Istefanopulos, Y. ve Khorasani, K., (2007). Optimal nonlinear controller design for flexible robot manipulators with adaptive internal model, IET Control Theory Applications, 1, 3, 770-778.
  • Moallem, M., Patel, R.V. ve Khorasani, K., (2001). Non-linear tip position tracking control of a flexible- link manipulator: theory and experiments, Automatica, 37, 1, 1825-1834.
  • Xu, R. ve Ozguner, U., (2008). Sliding mode control of a class of underactuated systems, Automatica, 44, 1, January, 233-241.
  • Sabanovic, A., (2007). SMC framework in motion control systems, International Journal of Adaptive Control and Signal Processing, 21, 9, October/ November, 731-744.
  • Kostic, D., Jager, B. de ve Steinbuch, M.,(2002). Robust attenuation of direct-drive robot-tip vibrations, Proceedings 2002 IEEE/RSJ, International Conference on Intelligent Robots and Systems, EPFL, Lausanne, Switzerland, 2206-2212.
  • Chen, X. ve Fukuda, T., (2001). Robust slidingmode tip position control for flexible arms, IEEE Transaction on Industrial Electronics, 48, 6, 1048-1056.
  • Chen, X., Sue, C.-Yi ve Fukuda, T., (2003). Robust vibration control for flexible arms using the sliding mode method, Asian Journal of Control, 5, 4, 594-604.
  • Gökasan, M., Bogosyan, S. ve Sabanovic, A., (1998). A sliding mode observer and for a single link arm, Conference on Decision and Control, CDC'98, Tampa, Florida, 3625-3626.
  • Fridman, L., (2002). Singularly perturbed analysis of chattering in relay control systems, IEEE Transaction Automatic Control, 47, 12, 2079-2084.
  • Emelyanov, S.V., Krovin, S.K. ve Levant, A., (1993). Higher-order sliding modes in control systems, Differential Equations, 29, 11, 1627- 1647.
  • Vuilmet, C., (2005). High order sliding mode control applied to a heavyweight torpedo, in Proceedings 2005 IEEE Conference on Control Applications, CCA’05, Toronto, Canada, August, 61-66.