Gen'ichi Yasuda

Distributed autonomous control of modular robot systems using parallel programming

Abstract This paper describes the design and implementation of a modular distributed architecture for distributed autonomous control of modular robot systems using parallel programming in industrial robotic manufacturing applications. The control system has an overall hierarchical structure, and parallel structure in its lower levels. The lower levels are composed of several autonomous units; each unit is equipped with a microprocessor-based controller, and has its own control functions with sensors, actuators, and communication interfaces as an intelligent autonomous sensing and actuating device. Operations of these autonomous actuators are integrated through a communication network of serial bus type. An autonomous actuator is a basic unit for distributed motion control of a robotic mechanism. Because of the hardware and software modularity, they have the advantages such as reduction of system costs, application flexibility, system reliability, and system extensibility. A microcontroller-based flexible and extensible architecture is proposed, and the features of distributed microcontroller implementation are discussed. For a two degrees of freedom robotic mechanism, a mobile robot with two coaxial independently driving wheels, position and velocity control algorithms to follow a planned path cooperatively are implemented, and the performance of the proposed architecture is experimentally evaluated.

Petri net model based specification and distributed control of robotic manufacturing systems

The specification and distributed control of discrete event robotic manufacturing systems using Petri nets are considered, and a methodology of decomposition and coordination is presented for hierarchical and distributed control. First, a task specification is defined as a Petri net model at the conceptual level, and then transformed to the detailed Petri net representation of the subtasks. Finally, the overall Petri net is decomposed and the constituent subnets are assigned to local Petri net based controllers. The controllers are coordinated by the coordinator so that the decomposed transitions fire at the same time. System coordination algorithm through communication between the coordinator and the controllers, is presented. By the proposed method, modeling, simulation and control of large and complex manufacturing systems can be performed consistently using Petri nets.

A Space-Division Optical Wireless Communication System for Fully Distributed Multiple Autonomous Mobile Robots

Abstract This paper describes the realization of a space-division optical communication system specifically designed to perform local inter-robot communication in fully distributed multiple autonomous mobile robot systems. Requirements for autonomy and robustness of communication functions among moving robots are discussed. The communication system uses a set of modules, or transceivers, which is arranged in the circumference of the robot body. Each module comprises an IR detector/receiver and an IR transmitter. Each IR module detects the angle of incidence of infrared rays. Space-division communication networks can be created, because a robot can commumcate with more than one robot through different modules at the same time. Hardware realization and performance measurements are illustrated to reveal the effectiveness of the developed system.

An object-oriented multitasking control environment for multirobot system programming and execution with 3D graphic simulation

This paper describes an object-oriented distributed control environment for industrial multirobot applications. A distributed computing environment, where workpieces, robots, and other industrial devices such as a vision sensor are defined as software objects with class inheritance hierarchy, supports human-friendly task-level programming and automated robot program generation with 3D graphic simulation, and performs supervisory and real-time sensor-based coordinated control of multirobot systems. Using object-oriented multitasking control with a preemptive rescheduler, vision-based robot positioning and pick and place operations for exchange of a workpiece are demonstrated to validate the control performance of the computing environment.

Distributed Implementation of Communicating Process Architectures for Autonomous Mobile Robots

Abstract This paper describes the implementation of a parallel distributed control architecture for autonomous mobile robots. Based on a modular and hierarchical approach, the control architecture is defined as a set of communicating sequential processes of autonomous sensing and control modules. The distributed implementation of the process interaction network is realized through synchronous and asynchronous communications among concurrent processes. A method for coordinating obstacle avoidance and trajectory tracking using fuzzy logic is presented based on the concurrent sensing and control framework. The control architecture is successfully implemented for local control and servo control tasks using a network of microcontrollers connected via a serial bus.

A microcontroller-based architecture for locally intelligent robot agents

This paper describes the realization of a modular distributed control architecture specifically designed to control locally intelligent robot agents for the small or middle size league of Robocup. For the autonomy and robustness of the onboard control system with intelligent sensors and actuators, a microcontroller-based flexible and extensible architecture is proposed. The low-level intelligent sensing and actuating functions are combined with high-level behavioural procedures to provide distributed autonomous robot control intelligence.

A parallel distributed control architecture for multiple robot systems using a network of microcomputers

Abstract This paper presents the design and implementation of a parallel distributed control architecture for industrial multiple robot systems. The design methodology is based on a concept of discrete states and actions, and a robotic task is represented as a sequence of primitive actions. For cooperative or exclusive tasks at the synchronous level of multiple robot systems, Petri net representation is applied, and discrete event-driven control is implemented as a data flow network of concurrent processes communicating with each other. Implementation of multiprocessing control on a microcomputer and a network of microcomputers is discussed.

Object Recognition and Self-Localization for Interactive Soccer Robots

This paper presents an experimental study on object recognition and self-localization for multiagent robotic soccer. A color image segmentation method based on UV color information of each pixel of the color image is applied to the ball recognition and self-localization of a small mobile robot. First, the lower and higher threshold values of U and V are determined for the sample color markers. Then color image segmentation is performed using the tables that transform each value of U and V in a pixel to membership in several color classes. The position of objects on the field is efficiently and accurately calculated using a monocular camera. Self-localization is accomplished using the distances and orientations of two landmarks. Experimental results of real-time movement control are also presented

Distributed cooperative control of industrial robotic systems using Petri net based multitask processing

The methods of modeling and control of discrete event robotic manufacturing systems using Petri nets are considered, and a methodology of decomposition and coordination is presented for hierarchical and distributed control. First, a task specification is defined as a Petri net model at the conceptual level, and then transformed to the detailed Petri net representation of the subtasks. Finally, the overall Petri net is decomposed and the constituent subnets are assigned to local Petri net based controllers. The controllers are coordinated so that the decomposed transitions fire at the same time by the coordinator. System coordination algorithm through communication between the coordinator and the controllers, is presented. By the proposed method, modeling, simulation and control of large and complex manufacturing systems can be performed consistently using Petri nets.

Petri net based implementation of hierarchical and distributed control for discrete event robotic manufacturing systems

The methods of modeling and control of discrete event robotic manufacturing systems using Petri nets are considered, and a methodology of decomposition and coordination is presented for hierarchical and distributed control. Based on a task specification, the conceptual Petri net model is designed and transformed to the detailed net representation of the subtasks. The overall net model is decomposed and the constituent subnets are assigned to local Petri net based controllers. The controllers are coordinated so that the aggregated behavior of the distributed system satisfies the task specification completely. By the proposed method, modeling, simulation and control of large and complex manufacturing systems can be performed consistently using Petri nets.