Research On Mobile Robot Behavior Control Based On Multi-Sensor

As the robot application range extends constantly, its working condition is getting more and more complex, which is always unknown, dynamic and unstructured. So, it is a new challenge for robot to fulfill a mission in real time under these environments. The idea of mobile robot behavior control based on multi-sensor is put forward according to a survey of the research on mobile robot control architectures and navigation technology, and a summary of the shortage in local vision-based navigation: it is difficult to acquire adequate visual information from proper view point; it is difficult to acquire and maintain a consistent model of a wide dynamic environment. A mobile robot navigation control experiment system under a fixed area in the unstructured and dynamic environment is built for the main purpose of this dissertation to study on environment perception, behavior decision, motion control, mission distribution and corresponding control among the distributed vision agents, and so on, in the objective-oriented mission mobile robot behavior control. The main contents of this dissertation are as follows:An autonomous navigation control experiment system (ANCES) is well developed which can applied to mobile robot behavior control, active vision-based (local vision-based) navigation, distributed vision-based navigation and other correlative research domains. The system consists of a mobile robot (RIRA-II ROBOT), a distributed vision system and a set of communication system.The study on the architecture of mobile robots is carried out. A modularized distributed control system architecture based on multi-processor with parallel communication is put forward and employed in the hardware system design for RIRA-II ROBOT. Each module is controlled by an individual processor and the data processing is tackled by the same one processor. All modules run and communicate with each other in a parallel method, which improves the speed of data transmission and simplifies the software programming. Deliberated/reactive hierarchical hybrid architecture is used in the software of RIRA-II ROBOT, which consists of a human-machine interface layer, a mission planning layer and a behavior control layer.A distributed ultrasonic detecting system based on multi-processor is developed. The detecting system adopts upper-lower two layers distributed control architecture. It is composed of an upper working method control module and a lower intelligent ultrasonic ranging module array. Each intelligent ultrasonic ranging sensor is controlled by an individual micro-processor which achieves ranging data processing, and the intelligent ultrasonic ranging modules can be grouped to work in parallel mode, which enhances the real-time performance. The threshold comparison method and an advanced data shift average filtering method are employed in the ranging data processing, which can restrain the ultrasonic crosstalk and random interference and improve the accuracy of the detecting system.This dissertation investigates deeply behavior control strategy for mobile robot based on multi-sensor (vision, sonar and infrared) information. Priority-based behavior decision is adopted to control the robot. The RIRA-II ROBOT can also accomplish the objective-oriented mission utilizing visual perception. RIRA-II ROBOT has 3 behavior modules: goal approaching behavior, fuzzy control behavior and escape behavior, each module has a given priority. The behavior arbiter decides which behavior module can control the robot by their given priority when the behaviors are valid.The study on configuration and work principle of distributed vision system(DVS) is carried out. The global image of robot's working environment is obtained by mosaicing the images acquired by the vision agents; The search for global path is achieved according as the given restriction after quadtree environment mode building; A global path from the start point to end point is obtained by utilizing cubic spline curve to math the searched path line; The DVS decompounds the planned path and distributes them to correlative vision agents. The vision agents can control a mobile robot to fulfill the given mission by corresponding mechanism.The study on mobile robot dynamic obstacles avoiding strategy in global navigation is carried out. Something that appeared on the path planned by DVS is regarded as dynamic obstacles which are classified into 3 kinds: passengers, motorial obstacles and static obstacles. The robot can distinguish the above dynamic obstacles by using the information of ultrasonic detecting system, human detecting module and active vision system. The robot can avoid the dynamic obstacles appeared in global navigation using different obstacle avoiding strategy.The research on DVS-based mobile robot path tracking is carried out. A fuzzy path tracking control method based on fixed-step preview point is adopted. In this method, controlling the motion of mobile robot is simplified to control rotation about its instant center. The fuzzy controller has two input parameters: one is the distance error between the current robot's position and the desired current position on the path; the other is angle error between the bearing of robot's current position and the bearing of robot's predictive position on the desired path in next control cycle. The output of the fuzzy controller is the rotation angular velocity of the robot.The modularized distributed control system architecture based on multi-processor with parallel communication and the design and manufacture methods of DVS in ANCES show the characteristics of practicability and expansibility in intelligent robot research.