Tez Türü: Bütünleşik Doktora
Tezin Yürütüldüğü Kurum: Kocaeli Üniversitesi, Mühendislik Fakültesi, Mekatronik Mühendisliği, Türkiye
Tez Danışmanı: Zafer Bingül
Tezin Onay Tarihi: 2014
Tezin Dili: İngilizce
Desteklendiği Program: Diğer
Özet:
RSEA (rotary series elastic actuator) is one of the fundamental problems in the control theory field. To verify the modern control theory, RSEA may be considered as a better example in control engineering. The RSEA is a highly non-linear and open-loop unstable system that makes the control more challenging. It is an intriguing subject from the control point of view due to its intrinsic nonlinearity. The RSEA include a nonlinearity due to the frictions in the joints. Common control approaches require a good knowledge of the frictions in the joints of the system and accurate friction estimation to obtain the desired performances of feedback controllers. However, the frictions have high non-linear values, which result in steady-state errors, limit cycles, and poor performance of the system. It has an influence on the system's response, and it should be considered seriously. Therefore, friction estimation has the potential to ameliorate the quality and dynamic behavior of the system. For humanoid/memetic robots, modeling and accurate torque trajectory control of a rotary series elastic actuator (RSEA) is of great importance. In this study, the fuzzy logic torque controller with nonlinear friction compensation (NLFC) is used to improve the deteriorating trajectory tracking performance caused by these nonlinear elements in RSEA systems. In order to demonstrate the power efficiency and performance of the proposed control system, several experiments have been performed on the experimental setup, including a torque motor with worm gear and torsional flat-double spiral spring (TFDSS). The proposed novel RSEA is designed and tested using different controllers, including PID feedforward controller (PID-FFC), fuzzy logic feedforward controller (FL-FFC), and fuzzy torque controller with friction compensation (FTC-FC). A comparative study among controllers is conducted to show the robustness of FTC-FC against a step and ramp type disturbances. The simulation and experimental results here strongly confirm that the proposed control method produces better control performance. Another aim of this thesis is to develop non-linear controllers for the impedance control problems. In this paper, a new fuzzy adaptive fractional hybrid Impedance (FAFHI) control approach is developed for high-sensitive contact stress force tracking control of the rotary series elastic actuators (RSEAs) in rugged terrains. The aim of this study is to obtain an adaptive hybrid impedance control model (AHICM) which depends on both position and torque in a large range of motion trajectory that involves difficult and sudden large changes. In three different cases, the fractional parameters of the FAFHI control were optimized with the particle swarm optimization algorithm (PSO). Its adaptability to the pressure of the sole of the foot on real environments such as grass (soft), carpet (medium), and solid floors (hard) is far superior to traditional impedance control. Hence, the torque error triggered by the time-varying stiffness environment can be compensated by using our fuzzy adaptive algorithm. Simulations are tested on an RSEA, in order to verify the torque control accuracy as well as its
robustness in terms of a time-varying stiffness environment. Both the simulation and the experiment show that our proposed control scheme has a better performance on maintaining the desired contact force than hybrid impedance (HI) control and fractional hybrid impedance (FHI) control.