Second order sliding mode control for a fan system based on MCU

• Main Authors: Kuo-Jheng Fan, 范國徵
• Other Authors: Huann-Keng Chiang
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/02354872087911225743

碩士 === 國立雲林科技大學 === 電機工程系 === 103 === The Fan wind speed control system (FS) is a self-made experimental system that is designed to improve the efficiency of the air-condition system in buildings by control methods. According to Fan’s Law, a fan operating at 50% output wind volume requires only 12.5% of the power required at 100% output wind volume. In other words, under the condition of same air speed the system with air speed controller has better efficiency through improving the control ability. FS is a nonlinear system which has many uncertainties and interference around the system. In classical control, the linearized method is only suitable in a small operating region. The system cannot be controlled or out of control when the parameter variations and external disturbance makes the operating point out of the operating region. Therefore, we use the several nonlinear control algorithms to reduce interference of the uncertainty on microchip controller dsPIC30F4011. The component of external disturbance simulates the situation of tube blocking in the actual system. The second-order sliding mode control (SOSMC) overcomes the serious chattering phenomenon in conventional sliding mode control method and has good anti-uncertainty ability. In this thesis, we selected three SOSMC algorithms for wind speed control of FS. They are (i)Lyapunov based SOSMC algorithm, (ii)Sub-optimal Algorithm, and (iii)Drift Algorithm. The Lyapunov-based SOSMC guaranteed the stability by the Lyapunov second theorem. Sub-optimal SOSMC and drift SOSMC choose different control laws in phase plane which have different convergent trajectories. Both algorithms have good convergence property in the system parameters unknown if the upper boundary is suitable chosen.