Autonomous Mobile Robot System Research Articles

Development of tethered autonomous mobile robot systems for field works

This paper describes the implementation details, advantages and potential applications of autonomous tethered mobile robot systems using the 'hyper-tether' concept. Hyper-tether is a new research area on tethered connections, which provide tethering among different mobile robot types, such as a robot with the environment and a robot with humans and animals. Its basic function is to actively control the tether's tension and/or length, but it also considers tether launching, anchoring, power delivery, data communication cabling and built-in trajectory command generation capabilities. Many of these features can be efficiently applied to build a tethered mobile robot system which remotely manipulates a working tool that can be useful for land-mine detection and removal, trimming of gardens and grass cutting of wide areas (e.g. golf courses, soccer and baseball fields), spraying of agricultural chemicals, forestry and construction works, etc. In this paper, a simple prototype of hypertether's winch-tether pair and a working tool equipped with a grass cutter was constructed, and basic experiments were performed to demonstrate the validity of the proposed system.

A robot self-localization system based on omnidirectional color images

A self-localization system for autonomous mobile robots is presented. This system estimates the robot position in previously learned environments, using data provided solely by an omnidirectional visual perception subsystem composed of a camera and of a special conical reflecting surface. It performs an optical pre-processing of the environment, allowing a compact representation of the collected data. These data are then fed to a learning subsystem that associates the perceived image to an estimate of the actual robot position. Both neural networks and statistical methods have been tested and compared as learning subsystems. The system has been implemented and tested and results are presented.

Vision Based Navigation System for Autonomous Mobile Robot. Locomotive Experiments Based on Variable Template Matching.

We have previously developed a navigation system for autonomous mobile robots. It can find landmarks on the ceiling to move and work. However it is impossible to recognize landmark in case that the size of landmark is different from the size of template. In such cases, the robot cannot continue to work. Therefor we proposed Variable Template Matching (VTM) which makes it possible to recognize landmarks of different sizes. We realize VTM by using the optimization method that is called Evolution Strategy (ES). The robot can recognize the landmark faster by binary density projection to infer landmark parameters. Minus Fuzzy Template is useful for the robot to avoid misidentifying.

Vision Based Navigation System for Autonomous Mobile Robot. Locomotive Experiments Based on Global Matching.

We have previously developed a navigation system for an autonomous mobile robot. It can find the landmarks on the ceiling to move and work. However, when the robot fails to recognize a landmark, the robot can not calculate self-position. So, the robot has to prepare for the behavior of error recovery. But an error that is not able to recover may occur. In such a case, the robot needs to relocate the self-position. In this paper, we define Global matching as the behavior that is able to relocate the self-position and proposed this module for the final module of error recovery in HALAS(Hierarchical Adaptive and Learning Architecture System)that have been proposed as Hierarchical System by us.

A Short History of Cleaning Robots

The definition of the desired functions and the design of an ultimate versatile personal robot is an ongoing debate. Meanwhile, however, precursors of this yet to evolve species are well on their way to become commercial products. Cleaning robots for public environments as well as for private households seem to be able to provide the breakthrough which the designers of non-industrial robot systems have long awaited. This survey describes a selection of 30 different cleaning robots, with the first developments reaching back more than 15 years. With a few exceptions we have focused on floor cleaning, in particular indoor floor cleaning. We describe a variety of scrubbing and vacuuming robots which were developed for this task. The described systems range from heavy, large, and expensive industrial cleaning vehicles to small-size, light-weight, low-cost household devices. The survey does not include, however, systems for cleaning facades of buildings, or windows, or production tools. Although not all of the 30 cleaning robots abovementioned have yet reached the state of commercial products, their number alone certainly reflects the expectations regarding the economic value associated with the automation of cleaning tasks. In Europe only the estimates for the market for cleaning services range up to the order of USd 100 billion per year. It is therefore not surprising that the cleaning industry and the manufacturers of cleaning devices are rather enthusiastic with respect to the automation of cleaning tasks using (semi-)autonomous mobile robot systems.

304 自走型溶接ロボットによる溶接線の認識および追従制御(OS 加工・検査のロボット化・知能化)

An autonomous mobile robot system with a visual sensor for automatic welding was developed. Algorithm for recognition of welding line and automatic seam-tracking was constructed. The robot has a. movable arm of which position is controlled on cylindrical coordinates and two driving wheels which are equipped at both sides of the vehicle body. The CCD camera is equipped on the movable arm and detects welding line from upper side of base materials. The constructed system can recognize welding line with a visual sensor robustly and track welding line with enough precision and speed as basic performance of welding robot. Consequently, it was confirmed that the system has enough availability and effectiveness to automatic welding.

Open Control Architecture for Mobile Robot

This paper is focused on design and development of cognitive control system for autonomous mobile robots. The control system contains three fundamental parts: planning algorithms, strategy switching mechanism and module for data fusion and extraction. For testing it is important to have open control system that enables easy addition of new planning algorithms. Our rule based system for decision making is introduced and three basic sensor-based planning algorithms are described. The crucial part of the system is transformation knowledge between different representations. We will suggest two methods that extract line segments from sonar data. All algorithms were tested on real mobile robot equipped with sonar range finders.

Vision Based Navigation System for Autonomous Mobile Robot. Locomotive Experiments Based on Variable Template Matching.

We have previously developed a navigation system for autonomous mobile robots. It can find landmarks on the ceiling to move and work. However it is impossible to recognize landmark in case that the size of landmark is different from the size of template. In such cases, the robot cannot continue to work. Therefor we proposed Variable Template Matching (VTM) which makes it possible to recognize landmarks of different sizes. We realize VTM by using the optimization method called Evolution Strategy (ES). The robot can recognize the landmark faster by binary density projection to infer landmark parameters. Minus Fuzzy Template is useful for the robot to avoid misidentifying.

Coordinated Motion and Force Control of Multi-Limbed Robotic Systems

This analytic and experimental study proposes a control algorithm for coordinated position and force control for autonomous multi-limbed mobile robotic systems. The technique is called Coordinated Jacobian Transpose Control (CJTC). Such position/force control algorithms will be required if future robotic systems are to operate effectively in unstructured environments. Generalized Control Variables (GCVs), express in a consistent and coordinated manner the desired behavior of the forces exerted by the multi-limbed robot on the environment and a system‘s motions. The effectiveness of this algorithm is demonstrated in simulation and laboratory experiments on a climbing system.

Trajectory generation for a four wheel steering tractor-trailer system: a two-step method

A basic problem in the development of an intelligent vehicle/highway system (IVHS), or an autonomous mobile robot system (AMRS) is to find suitable input controls which can be used to drive the vehicle between any two configurations. In this paper a trajectory generation problem for a four-wheel-steering tractor/semi-trailer system is investigated, and it is shown that this nonholonomic constraint problem can be converted into one of finding fitting-functions satisfying certain necessary boundary conditions. Proposals for control laws are presented and simulation results for a lane change manoeuvre are given.

Autonomous vehicle parallel parking design using function fitting approaches

One of the most fundamental problems in the development of an intelligent highway system or an autonomous mobile robot system for factory use is to find the necessary input control variables for smooth and safe movement of the vehicle, or robot, between any two configurations. In this paper it is demonstrated that this problem can be converted into one of finding a fitting function which satisfies the boundary conditions. Three curves, a quintic polynomial, a cubic polynomial and a triangular function are developed to perform the parallel transfer manoeuvre which forms the basis of several important manoeuvres such as reverse parking, moving off, negotiating a stationary obstacle, overtaking a moving vehicle, and changing lane. A detailed discussion of the effect of the vehicle's steering angle limit on the feasibility of these manoeuvres is presented. Simulation results using three typical vehicles, a long commercial vehicle, an ordinary car, and a small laboratory robot, travelling along three curves are also presented and discussed. Based on the comparative study, some suggestions for further work are made. Compared with other methods, this approach is simple and provides excellent simulation of human driver techniques. The paper concludes with a focused discussion about the integration of these techniques with satellite based GPS systems for automated vehicle guidance on highways.

Autonomous Mobile Robot System for Long Distance Outdoor Navigation on University Campus

We are developing a self-contained and autonomous mobile robot that can navigate around our university campus. In this paper, we discuss issues important to a robot which has sufficient intelligence and toughness to withstand the rigors of outdoor navigation. Then, we report on our mobile robot ""YAMABICO NAVI,"" which has many integrated functions such as locomotion, position estimation and sensors that detect landmarks and obstacles as an example. Furthermore, we describe an execution monitoring tool that is used to observe the internal state of the robot outdoor experiments.

Development of a Construction Robot for Marking on Ceiling Boards

Previously, we proposed a self-positioning measurement system for autonomous mobile robots at work sites.1-4)The system depends on the basic principle of triangulation. Preparations are not required for specific reference points, but use pillars standing on the floor. We also developed a prototype robot that utilizes the system. The marking robot leaves a specific mark at the installation position for apparatuses on ceiling boards in large buildings. The robot moves autonomously, recognizes its position, and draws figures with an error of a few millimeters on the ceiling board. It can reach a height of about 3000mm.

Relative position localizing system for multiple autonomous mobile robots in distributed robotic system: System design and simulation

Abstract Coordination strategies and algorithms for a system with multiple autonomous mobile robots often require a robot to know the relative position of other robots in its vicinity (Beni and Wang, 1991; Wang, 1993; Wang and Premvuti, 1994). Many experimental systems employ centralized localization mechanisms, which are invalid for a fully distributed robotic system. An ideal mechanism for relative localization is a fully autonomous passive sensing system (Graefe, 1989; Miura and Shirai, 1994), such as stereo vision, which involves great degree of sophistication and high cost. In this paper, an alternative autonomous relative localization strategy is proposed. Measurement of distance is based on detecting linear velocity of a vertical slit laser beam from a rotating beacon that projected on the photodiode array mounted in round belt shape installed on a robot. Linear velocity of sweeping beam on the sensor array can be interpreted as the distance from a beacon based on an equation. v=rw where v is the linear velocity of the laser beam projected on sensor array which can be measured, r is the distance from a beacon to the sensor array which we want to know, and ω is the angular velocity of beacon which is constant and known. Direction is also detected by locating area on the sensor array where the beam is projected and finding the center of that area.

Self-Position Measuring Method for Moving Robot Working at Construction Sites. 2nd Report. Improvement of Pillar-Detecting Algorithm.

This paper describes a new self-position measurement system for autonomous mobile robots working at building sites. The robots must be able to position themselves precisely at desired locations for building operations. Although the method depends on the basic principle of triangulation, no preparations are required for establishing reference points. On the floor of a large building, pillars standing in known positions at intervals of about 10 meters can serve as reference objects. Experimental results obtained using the prototype system, which was composed of a laser range finder and an angle-measuring unit, proved that this system was able to determine its position with an error of±5 millimeters.

Navigation System for Air Conditioning Equipment Inspection Robot

We have previously proposed a navigation system for autonomous mobile robots that can recognize regular ceiling landmarks. This system can find square air diffusers on ceilings by sensing their multiple-quadrangle characteristics. We have now developed a new system that is able to recognize circular air diffusers. In addition, certain lighting conditions which obstructed recognition in the original system do not interfere with the newly proposed system. Here we applied Fuzzy and Neural Network Logic technology. A pre-processed image of a landmark is compared with a fuzzy template made from the fuzzy membership function. In order to find specific landmarks, the system determines the degrees of similarity by comparing the sited object with a variety of templates stored in its memory. Then a Neural Network uses results of this calculation to hone in on its target. So, the system can recognize many different kinds of landmarks. This paper shows the principle of this system and experimental results.

Circle in the round: State space attractors for evolved sighted robots

This paper presents an analysis of an artificially evolved dynamical network-based control system for a simulated autonomous mobile robot engaged in simple visually guided tasks.

Coordination of Mobile Robots by Estimating Relative Spatial and Temporal Uncertainties

In decentralised systems of autonomous mobile robots the relative motion between the robots must be controlled. Consequently, the uncertainty of the robots’ states relative to each other must be considered. The method developed offers a way to model robot motion in spacetime. Spatial and temporal uncertainties of the robots relative to each other are modelled simultaneously. This is necessary, since the robots exploit delayed communication data on the control level in addition to up-to-date sensed data. Simulations and experiments conducted up to now are reported.

Vision Based Navigation System of Autonomous Mobiel Robot. Landmark Detection using Fuzzy Template Matching.

In this paper, we propose a vision-based navigation system for autonomous mobile robots which recognizes outlets of the air conditioning system (anemo) located on the ceiling as landmarks. Because landmarks on the ceiling are not obstructed by other objects, robots can find them more easily than landmarks on the floor. To detect the landmark, we applied template matching whose template consists of fuzzy sets. The grades of fuzzy membership are input into a neural network (NN). NN leads a template to the landmark location. The navigation system can calculate the distance and the angle of the anemo from map information. As a result, the navigation system can identify the present robot's position and orientation. By the proposed algorithm, precise and fast landmark detection becomes possible even if the landmark follows shadows.

A multisteering trailer system: conversion into chained form using dynamic feedback

This paper examines the kinematic model of an autonomous mobile robot system consisting of a chain of steerable cars and passive trailers, linked together with rigid bars. The state space and kinematic equations of the system are defined, and it is shown how these kinematic equations may be converted into a multiinput chained form. The advantages of the chained form are that many methods are available for the open-loop steering of such systems as well as for point-stabilization; some of these methods are discussed here. Dynamic state feedback is used to convert the system to this multiinput chained form. It is shown how the dynamic state feedback that is used in this paper corresponds to adding, in front of the steerable cars, a chain of virtual axles which diverges from the original chain of trailers. Two different example systems are also presented, along with simulation results for a parallel-parking maneuver.