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This paper introduces the method of detecting a route space for an industrial indoor vehicle. The vehicles work in many industrial fields, e.g., a semiconductor production and a car assembly factory. The detection of the route space under illuminant disturbance is an important problem for the industrial vehicle robot. The industrial vehicle has to move to the same areas in a factory. For these works,...
In this paper, a new methodology for robust segmentation of obstacles from stereo disparity maps in an on-road environment is presented. We first construct a probability of the occupancy map using the UV-disparity methodology. Traditionally, a simple threshold has been applied to segment obstacles from the occupancy map based on the connectivity of the resulting regions; however, this outcome is sensitive...
Lateral localization of an autonomous vehicle within its lane is major information for its adequate control and navigation. Computer vision and robotics communities have used primarily images to Bird's Eye View for easier data manipulation than perspective image. Nevertheless, this technique usually assumes that the terrain is flat and needs calibration for its transformation matrix. In this paper...
This paper shows that a comprehensive multivariable approach of autopilot design that mixes sliding mode and PID leads to robustly satisfactory results for underwater mobile robot. The 6-DOF linear equations of motion can be divided into three subsystems for speed control, steering, and diving. The sliding mode algorithm is designed for steering control and PID is used for diving and speed control...
This paper presents design and experimental validation of a vehicle lateral controller for autonomous vehicle based on a higher-order sliding mode control. We used the super-twisting algorithm to minimize the lateral displacement of the autonomous vehicle with respect to a given reference trajectory. The control input is the steering angle and the output is the lateral displacement error. The particularity...
Dubins' result on paths of minimum length and bounded curvature led to a popular method of path planning for constant-speed vehicles moving in the horizontal plane. Constructing a Dubins path involves stitching segments that correspond to maximum rate turns and straight-line motions. However, a path that requires a maximum rate turn cannot be tracked, in general, because feedback corrections that...
Unknown and uncertain disturbance significantly affects the performance of a active steering control such as lane keeping and lane changing control. Such performance degradation is here considered to be due to input equivalent disturbance that is to be compensated by the state space disturbance observer we are to design. In contrast to some existing methods that employ explicit models for disturbance...
In this paper, we propose a robust multirate controller for steering control of autonomous vehicles. The goal of this research is to fuse the vision processer and motion sensor for the lane keeping and lane change systems. A robust multirate Kalman filter is designed to estimate the vehicle states and lane information at a fast sampling rate. This method provides the robust performance against uncertain...
The problem of formation control of multiple unmanned ground vehicles (UGVs) is studied in this paper. The underlying problem is essentially a high dimensional multi-vehicle trajectory tracking control problem, its complexity grows significantly as the number of the involved vehicles increases. To address the singularity inherent in regular formation process and the complexity involved in formation...
Robust path following capability is mandatory for an unmanned boat to perform tasks autonomously. This paper presents a mixed H∞/H2 based control which enables the boat to follow paths with connected straight line segments and circular arcs in the absence of yaw angle measurement. The performance of the strategy is evaluated in field test and will be discussed in the paper.
The authors previously proposed an Unmanned Ground Vehicle (UGV) in an orchard as a base platform for autonomous robot systems for performing tasks such as monitoring, pesticide spraying, and harvesting. To control a UGV in a semi-natural environment, accurate self-localization and a control law that is robust under large disturbances from rough terrain are the first priorities. In this paper, a self-localization...
This paper presents design of a robust hovering controller for a quad tilt-wing UAV to hover at a desired position under external wind and aerodynamic disturbances. Wind and the aerodynamic disturbances are modeled using the Dryden model. In order to increase the robustness of the system, a disturbance observer is utilized to estimate the unknown disturbances acting on the system. Nonlinear terms...
This paper describes a real-time stereo vision sensor based on the Field Programmable Gate Array (FPGA). It was developed using an image matching algorithm called Orientation Code Matching (OCM). Our implementation, using OCM, provides not only high performance, but also flexibility and a greater robustness, all of which are necessary to embed vision sensors in mobile robots and vehicles. The prototype...
A robust 2-D vehicle-positioning system based on constraint propagation on a data horizon is proposed. Using asynchronous unreliable absolute positions and reliable proprioceptive measurements, the proposed method outputs the bounds of the pose at any desired rate. A bounded error approach is used to propagate the imprecision of the input data to the final pose estimation. Measurements are represented...
Traditionally, mobile robot design is based on wheels, tracks or legs with their respective advantages and disadvantages. Very few groups have explored designs with spherical morphology. During the past ten years, the number of robots with spherical shape and related studies has substantially increased, and a lot of work is done in this area of mobile robotics. Interest in robots with spherical morphology...
This paper describes a generic method for vision-based navigation in real urban environments. The proposed approach relies on a representation of the scene based on spherical images augmented with depth information and a spherical saliency map, both constructed in a learning phase. Saliency maps are built by analyzing useful information of points which best condition spherical projections constraints...
Visually estimating a robot's own motion has been an active field of research within the last years. Though impressive results have been reported, some application areas still exhibit huge challenges. Especially for car-like robots in urban environments even the most robust estimation techniques fail due to a vast portion of independently moving objects. Hence, we move one step further and propose...
A new filtering robust adaptive formation guidance law is proposed for unmanned surface vehicles (USVs) in the presence of uncertain leader dynamics. Using the approximation properties of neural network (NN) and adaptive bounding technique, the developed controller does not require the knowledge of the velocity of the leader. The derived guidance law is a velocity command for the follower and guarantees...
This paper presents a novel and computationally inexpensive method for motion planning of autonomous parallel parking of four wheeled nonholonomic vehicles. The proposed method makes use of Trajectory Shaping Guidance, given in [1] and [2], which was originally developed for missiles to hit the target at a given angle. This paper uses a modified version of Trajectory Shaping Guidance (TSG) for path...
Accurate modeling and simulation of submersible vehicle is essential for autonomous control and maneuverability research. In this paper, a variable direction rotatable axis of variable vector propeller (VDRA-VVP) is proposed and researched innovatively. The structure and working principle of VDRA-VVP of submersible vehicle are described and the nonlinear mathematic model of the submersible vehicle...
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