Examination Committee

Prof Shaojie SHEN, ECE/HKUST (Chairperson)
Prof Zexiang LI, ECE/HKUST (Thesis Supervisor)
Prof Fu ZHANG, ECE/HKUST

Abstract

To meet the demand of short-distance transportation, a novel type of intelligent mobility robot is proposed by this thesis. The robot features high portability, reliable safety and multiple control and interaction methods, including posture control and remote interaction. The robot has wide range of application prospects in both industrial production and daily life, such as travel, services, entertainment, etc.
 
To realize posture control of the robot, a complete set of posture perception system is designed and developed. Firstly the pressures on different sections are real-time acquired by specific sensors and corresponding detection circuit. Then based on the pressure distributions and statistic information, the posture is perceived by a series of processing algorithms, and is quantitatively described as inclination angles of body gravity center in two dimensions. Moreover, two machine learning methods are applied to further improve the accuracy of posture detection, including parameter regression method and Gaussian Process Dynamic Model. In addition, some auxiliary sensors are also applied to ensure the robustness and reliability through fusion of multi-sensor information fusion.
 
The planar kinematics of the robot is analyzed based on steering mechanisms, suspension systems, and differential speed of wheel pairs. The motion planning algorithm outputs desired motion parameters of the robot, such as longitudinal speed and turning curvature, based on both user input and kinematic constrains. To control the motion of the robot, distribute control strategy as well as fuzzy logic control algorithm are applied to coordinately assign appropriate control amount to multiple actuators of different types.
 
The design and control of actuators are discussed at last. The Field Oriented Control of the Permanent Magnet Synchronous Motor is designed and implemented to drive the motor and to control its speed and toque while improving energy efficiency. A kind of brake device is also designed to provide reliable and timely braking performance, wherein the braking force is adjustable.