| Summary: | 博士 === 國立中央大學 === 電機工程學系 === 105 === This dissertation proposes the design and implementation of fuzzy control for the chaos-based secure communication system (SCS) and hexapod robotic system. For the chaos-based SCS, two fuzzy-model-based approaches are proposed for synchronization the chaotic systems. The first approach proposes a T-S fuzzy-model-based finite-time chaotic synchronization design for the SCS. Firstly, the master and slave chaotic systems are exactly represented as the master and slave T-S fuzzy models respectively. Then the fuzzy controller is designed to guarantee that master-slave synchronization can be completely achieved within a pre-specified convergence time T even when an external disturbance exists in the slave system. The hardware of the chaos-based SCS with the proposed fuzzy control is implemented on a development board (Altera DE2-115), which comprises an Altera Cyclone IV 4CE115 FPGA chip, and on a personal computer (PC). In the second approach for SCS, a polynomial fuzzy-model-based design with considering a constraint on the control input is proposed to synchronize the multi-scroll Chen chaotic systems. Firstly, the master and slave multi-scroll Chen chaotic systems are exactly represented as the master and slave polynomial fuzzy models respectively. Then a polynomial fuzzy control is proposed for synchronizing the master and slave chaotic systems. Moreover, for restraining external disturbances and practical consideration, performance and a constraint on the control input are also considered in the polynomial fuzzy control design. The SCS is implemented by two personal computers (PCs) communicating with each other through a router. The master PC is with an Intel i5-5250U CPU, and the slave PC is with an Intel i5-3337U CPU. Moreover, the master and slave chaotic systems and the proposed polynomial fuzzy controller are implemented by the Simulink of MATLAB 2015b.
For the hexapod robotic systems, a fuzzy logic control is proposed such that the hexapod robot can stably walk on an incline. We apply the tripod gait for relatively fast walking. Moreover, according to the slope of an incline, the proposed fuzzy logic control modifies the posture of the hexapod robot such that the vertical projection of the center of gravity (COG) can be maintained in the support polygon. Moreover, the Denavit-Hartenberg (D–H) convention and forward kinematics are applied to calculate the positions of the motors and end points of the legs in the coordinate system of the robot’s body. An inertial measurement unit is settled at the center of the robot’s body to obtain the rotation matrix for calculating the vertical projection of COG when the robot is walking on an incline. Then, a fuzzy logic control is proposed to adjust the motor angles of supporting legs for maintaining the vertical projection of COG close to the COG of support polygon. The stability margin of the hexapod robot is maximized by the proposed fuzzy logic control, hence the robot can stably walk on an incline.
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