The Multifunction Lego Mobile Robot Design

With its high intelligence and capability of adaptation in complex environment, mobile robot is widely used in civil and military industry. This thesis introduces the conception of a mobile robot which is capable of searching and fetching objects based on the kit of NXT 2.0 mind storm produced by Lego Company.This thesis defines the behavior by applying hierarchical method and determines the design plans in the first place. This thesis then reveals the development details by introducing the mechanics and the software respectively. The main content is summarized in the following points:(1) The hierarchal method. We subdivide the global design tasks by introducing need analysis, the operational and technical constraint analysis, the modular design, the assemble design and determine the boundary of the aimed system.(2) The mechanics of the car chassis and the arm. The analysis of the motor and other actuators in the NXT kit are carried out through experiments. The mechanics are depicted by theoretical tools such as the geometrical models and Lagrange expression. The effectiveness and the feasibility of this design are proved by relative kinetic and mechanic studies.(3) The determination of sensor types and their installations. This thesis analyzes the hardware of the sensors and measures theirs characteristics by experiments and the installations.(4) The design of software system. This thesis applies the behavior based programming model and programs the robot through the standardized interface. Besides, this thesis also introduces the edge-recognition, object-searching modules and PC based monitoring program.(5) The ground and edge recognition algorithm. This thesis proposes a threshold and a priori knowledge based algorithm. The specific development of algorithm is coved and the effectiveness of the algorithm is proved.Finally, the merits as well as the shortages are summarized and the further developments are discussed.