Autonomous Navigation Control Research Articles

Developing an Autonomous Surface Ship for Sea Demining: First Steps

The paper describes the first steps of the development of an autonomous surface ship for sea demining. The objective is to substitute humans in a dangerous humanitarian task. The research has three main phases. The first one is to develop at laboratory scale the infrastructure for the final system. The second is devoted to medium scale tests in open air scenarios. The third phase is real scale operation. This paper refers to the first phase, in which a ‘universal control unit’ is being developed for autonomous navigation control. Software modules are also under development for on-board control with self-localization, and for area scanning trajectory generation and then tracking. The vehicle uses a towed fish. Both the towing cable and the fish generate electric and magnetic fields, to cause mine detonation by field influence. This study is made both with simulations and with scale experiments.

Fuzzy Logic Based Approach to Design of Flight Control and Navigation Tasks for Autonomous Unmanned Aerial Vehicles

This paper proposes a fuzzy logic based autonomous navigation controller for UAVs (unmanned aerial vehicles). Three fuzzy logic modules are developed under the main navigation system for the control of the altitude, the speed, and the heading, through which the global position (latitude---longitude) of the air vehicle is controlled. A SID (Standard Instrument Departure) and TACAN (Tactical Air Navigation) approach is used and the performance of the fuzzy based controllers is evaluated with time based diagrams under MATLAB's standard configuration and the Aerosim Aeronautical Simulation Block Set which provides a complete set of tools for rapid development of detailed six-degree-of-freedom nonlinear generic manned/unmanned aerial vehicle models. The Aerosonde UAV model is used in the simulations in order to demonstrate the performance and the potential of the controllers. Additionally, FlightGear Flight Simulator and GMS aircraft instruments are deployed in order to get visual outputs that aid the designer in the evaluation of the controllers. Despite the simple design procedure, the simulated test flights indicate the capability of the approach in achieving the desired performance.

Asymptotic Stability of Hierarchical Inner-Outer Loop-Based Flight Controllers

In this paper, we present a hierarchical controller for autonomous aerial vehicles control and navigation. For autonomous rotorcraft flight, it is common to separate the flight control problem into an inner loop that controls attitude and an outer loop that controls the translational trajectory of the rotorcraft. The resulted nonlinear controller is thus, easy to implement and to tune. Although satisfactory results have been reported in the literature and various navigational tasks have been achieved using this hierarchical control technique, this control scheme suffers from the lack of the stability proof and analysis of the closed-loop system. Here, we propose a 3D flight controller which is based on the inner- and outer-loop control scheme, and we prove the asymptotic stability property for the connected closed-loop system.

확률론에 기반한 점자블록 추종 알고리즘 및 센서장치의 개발

Under the situation of a fire, it is difficult for a rescue robot to use sensors such as vision sensor, ultrasonic sensor or laser distance sensor because of diffusion, refraction or block of light and sound by dense smoke. But, braille blocks that are installed for the visaully impaired at public places such as subway stations can be used as a map for autonomous mobile robot`s localization and navigation. In this paper, we developed a laser sensor stan device which can detect braille blcoks in spite of dense smoke and integrated the device to the robot developed to carry out rescue mission in various hazardous disaster areas at KIST. We implemented MCL algorithm for robot`s attitude estimation according to the scanned data and transformed a braille block map to a topological map and designed a nonlinear path tracking controller for autonomous navigation. From various simulations and experiments, we could verify that the developed laser sensor device and the proposed localization method are effective to autonomous tracking of braille blocks and the autonomous navigation robot system can be used for rescue under fire.

Human-Robot Interface over the Web Based Intelligent System

This research extends the capability for the new technology platform by Remote Data Inspection System (RDIS) server from Furukawa Co., Ltd. enabling the integration of standard Hypertext Markup Language (HTML) programming and RDIS tag programming to create a user-friendly “point-and-click” web-based control mechanism. The integration allows the users to send commands to mobile robot over the Internet. Web-based control enables human to extend his action and intelligence to remote location. Three mechanisms for web-based controls are developed: manually remote control, continuous operation event and autonomous navigation control. In the manually remote control the user is fully responsible for the robot action and the robot do not use any sophisticated algorithms. The continuous operation event is the extension of the basic movement from a manually remote control mechanism. In the autonomous navigation control, the user has more flexibility to tell the robot to carry out specific task. Using this method, mobile robot can be controlled via the web, from any places connected to the network without constructing specific infrastructures for communication.

Hierarchical fuzzy control for autonomous navigation of wheeled robots

The autonomous navigation wheeled robots (WR) requires integrated kinematic and dynamic control to perform trajectory tracking, path following and stabilisation. Considering a WR is a nonholonomic dynamic system with intrinsic nonlinearity, unmodelled disturbance and unstructured unmodelled dynamics, fuzzy logic system based control is appropriate and practical. However, the multivariable control structure of the WR results in the curse of dimensionality of the fuzzy design and prevents a domain expert from building the linguistic rules for autonomous navigation. Hierarchical fuzzy design decomposes the controller into three low-dimensionality fuzzy systems: fuzzy steering, fuzzy linear velocity control and fuzzy angular velocity control, so that manual construction of each rule base becomes feasible and easy. The proposed design enables a WR to perform position control in trajectory tracking and velocity profile tracking in continuous drive. The coupling effect between linear and angular motion dynamics is considered in the fuzzy steering by building appropriate linguistic rules. To facilitate the autonomous navigation design and verification, a prototype and the model of a kind of WR have been developed, and equipped with the hierarchical fuzzy control system. The simulation and experimental results are shown and compared.

Evolutionary algorithm for the promotion of evolvable hardware

Evolvable hardware offers much for the future of complex system design. Evolutionary techniques not only give the potential of a larger solution space, but also when implemented on hardware allow system designs to adapt to changes in the environment, including failures in system components. An evolutionary algorithm is developed that is solely based on a fitness-dependent mutation rate. One major objective for the authors is to produce an evolutionary system that is easily implementable on custom-off-the-shelf hardware. As an example of the system, an FPGA-based controller for a mobile robot is presented. The controller is made up of look up tables which perform the mapping from sensor data to actuator (commands to the motors) and it is evolved using the developed evolutionary algorithm. Experimental results obtained on a Khepera robot show that the method can successfully evolve a robot controller for autonomous navigation to avoid collisions in an unknown/changing environment even if sensor faults occur prior to the evolution or after a successful member of a population has been evolved.

REAL - a virtual laboratory built from software components

This paper presents the Remotely Accessible Laboratory (REAL), a virtual laboratory accessible through the Internet. REAL allows a remote user to manipulate a mobile robot in a mode of interaction suitable to his or her level of expertise. A basic mode of interaction, dedicated to users with limited knowledge of robotics, supports interaction via teleoperation. In a more advanced level of interaction, expert users can plan and execute complex robotics experiments that exploit the full capabilities of the robot. In this mode of interaction, experiments in the field of autonomous navigation, environmental mapping, sensor fusion, mission planning, and robot control can be performed. Finally, a third mode of interaction allows a set of trainees to follow the interactions conducted by an instructor. The architecture of REAL departs from the commonplace World Wide Web applications, since it employs a sophisticated software architecture based on software components. This architecture presents a high degree of reusability that future developments in the field of Internet robots and virtual laboratories can take advantage of.

Hybrid Control for Autonomous Mobile Robot Navigation Using Neural Network Based Behavior Modules and Environment Classification

A hybrid control architecture combining behavior based reactive navigation and model based environment classification has been developed. It is also hybrid in the sense that both competitive coordination and cooperative coordination are used for the BBC (Behavior Based Control) part. The contributions are as follows. First, a Neural Network (NN) in charge of environment classification has been developed based on 16 prototypes of topological maps roughly describing various local navigation environments. This environment classification NN not only enables the navigator to avoid local minimum points but also eliminates the requirement for prior detailed modeling of the environment since it needs to memorize only “rough” information on local environments encountered along the way that might be sufficient for navigation. Next, an NN based reactive behavior controller will be trained to learn human steering commands for each of the 16 prototype local environments. Third, the modified potential field (MPF) method obtained by adding the free space vector as the third component is used to select a particular reactive behavior in conjunction with the classification NN. Finally, a hybrid control architecture integrating all three of these concepts was developed. It avoids local minimum traps as well as solves the problems of poor obstacle clearance or oscillation. It is robust against sensor noise and adaptive to dynamic environments. This hybrid architecture is also amenable to easy addition of new behaviors due to the modularity of the BBC architecture. The effectiveness of the proposed architecture has been verified through both computer simulation and an actual robot called MORIS (MObile Robot as an Intelligent System).

A VLSI-Compatible Computer Vision Algorithm for Stereoscopic Depth Analysis in Real-Time

The analysis of the depth coordinates of objects in a visual scene is of vital importance for animals as well as in technological applications like autonomous robot navigation or product quality control. In this article we describe a phase-based algorithm for stereoscopic depth analysis which utilizes IIR-filters.1 This algorithm is especially well suited to be built into dedicated VLSI-hardware and can therefore, also be used as a fast real-time front end in any more general image processing system. Example movies which demonstrate the real-time capabilities of this algorithm can be found at: http://www.cn.stir.ac.uk/Real-Time-Stereo.

Development of a Laser Range Sensor for a Mobile Robot

External sensors which can detect environmental information are important for a mobile robot to recognize its surroundings and location. Among external sensors, range sensors are fundamental because they can directly detect the free space in which the mobile robot can move without colliding with the surrounding objects. A laser range sensor provides good spatial resolution, and it is expected to detect characteristic parts of the environment used as landmarks for recognizing robot position. This paper presents the construction of a laser range sensor system which can be implemented in a small mobile robot. The system consists of several components including laser diode, CCD camera, and mark detection hardware. Based on triangulation method, the system can detect the distance to the object's surface on which the beam spot is directed. In order to detect a landmark, such as a wall edge, the sensor system is mounted on a rotary table. By horizontally scanning, the sensor can detect wall edges with an accuracy of approximately 5mm and an orientation accuracy of approximately 1 degree within 3m. This system has been installed in an indoor mobile robot and is used for autonomous navigation control along corridors.