| Author | Sanjeewa, Sondarangallage D.A |
| Note | A dissertation submitted in partial fulfillment of the requirements for the
degree of Doctor of Philosophy in
Mechatronics |
| Publisher | Asian Institute of Technology |
| Abstract | The purpose of this research is to develop and control a Rotary type Double Inverted Pendulum (RDIP) System. Balancing control of a RDIP system is a challenging research topic for researchers in dynamics control field because of its non-linear, high degree-of-freedom, under actuated and unstable characteristics. The RDIP system uses only a motor to control two serially connected inverted pendulums. The system always works under uncertainties and disturbances. Several control algorithms fail or ineffectively control the RDIP system. This dissertation presents two robust controllers to stabilize the system: (i) Linear Quadratic Regulator (LQR) sliding surface based SMC, and (ii) mixed S/KS/T sensitivity H∞ control. In this dissertation, a rotary type double (serially connected) inverted pendulum system is designed and constructed. Mechanical structure of the system and electrical circuit are designed and implemented. Non-linear mathematical model is derived for the RDIP system using Euler–Lagrange equation of motion. A motor is used in the system. The model is linearized. System parameters are identified. In the dissertation, Linear Quadratic Regulator sliding surface based SMC (LQR-SMC) is proposed to balance the RDIP system. This control algorithm is developed based on the SMC. The LQR optimal gain is used to construct the optimized sliding surface of the proposed controller. Nonsingular gain matrix of the proposed optimized sliding surface is obtained by using left inverse of the input matrix in state space model of the system dynamics. The Lyapunov stability theorem is used to determine stability of the LQR-SMC controller. The uncertainties of the model are bounded by Euclidean norm. To evaluate the performance of LQR-SMC over the conventional SMC, some performance indices, including the Integral Absolute Error (IAE), Integral Time Absolute Error (ITAE) and the Integrated Square Error (ISE), are used. LQR-SMC can maintain system stability under external disturbances as well as parameter uncertainties. Results show that LQR-SMC can balance the system with better performance than the conventional SMC. In this dissertation, mixed S/KS/T sensitivity H∞ control is also proposed to balance the RDIP system. The controller is proposed to ensure the robust stability and enhance the time domain performance of the RDIP system under uncertainties and disturbances. For performance evaluation, the proposed mixed sensitivity H∞ controller is compared with LQR from both simulation and experiment on the RDIP. The results show good performance of the mixed S/KS/T sensitivity H∞ controller on the RDIP system under model uncertainties and external disturbances. |
| Year | 2019 |
| Type | Dissertation |
| School | School of Engineering and Technology (SET) |
| Department | Department of Industrial Systems Engineering (DISE) |
| Academic Program/FoS | Microelectronics (ME) |
| Chairperson(s) | Manukid Parnichkun; |
| Examination Committee(s) | Attaphongse Taparugssanagorn;Abeykoon, A.M. Harsha S.;Ota, Jun; |
| Scholarship Donor(s) | University of Vocational Technology
(UNIVOTEC), Sri Lanka. Skills Sector Development Project (SSDP); |
| Degree | Thesis (M. Eng.) -- Asian Institute of Technology, 2019 |