The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
The goal of the work in this paper is to use occupancy grid in integrating safety distances with the planning strategy for autonomous vehicle navigation. The challenge is to avoid static and dynamic obstacles at high speed with respect to some specific road rules while following a global reference trajectory. Our local trajectory planning algorithm is based on the method of clothoid tentacles. It...
This paper presents an approach of human-vehicle cooperative navigation system as an implementation of Advanced Driving Assistance Systems (ADAS). The driver-in-the-loop system contains commands by a human driver, which are verified and corrected by the interactive navigation algorithm based on Image-based Dynamic Window Approach (IDWA). Several autonomous driving components are involved including...
An Unscented Kalman Filter (UKF) to simultaneously estimate the navigation state of an Autonomous Underwater Vehicle (AUV) and the sea current, a priori unknown, is proposed. The filter is the result of a modification of an UKF developed in the past by the authors for the sole purpose of navigation state estimation. The new algorithm has been obtained by integrating the vehicle model with a contribution...
This paper addresses the problem of controlling an electric powered wheelchair in dynamic, crowded areas. Navigating the vehicle effectively in such environmental conditions requires two issues to be considered: Relatively long term prediction of pedestrians' motion and an influence of the vehicle motion on the people behaviour in its vicinity. The purpose of this study is to develop a method that...
Recently, increasing efforts have been focused on the development and adoption of autonomous underwater vehicles (AUVs) for various applications. However, the GPS signals are usually unavailable, the vehicle dynamics is very uncertain, and the complicated vision based localization algorithms may not work well in the underwater environments. Hence, accurate and timely state estimation using low-cost...
This paper presents a framework that integrates vector field based motion planning techniques with an optimal path planner. The main motivation for this integration is the solution of UAVs' motion planning problems that are easily and intuitively solved using vector fields, but are very difficult to be even posed as optimal motion planning problems, mainly due to the lack of clear cost functions....
An optimal design method for generating a flight path passing through specified waypoints while satisfying the task points sent by the ground operators is proposed in this paper. Each specified waypoint is reached exactly at the specified location and time while intermediate waypoints are generated in such a way that they satisfy the task points, with highest benefit measure, i.e., satisfying tasks...
In this work we address the position and attitude control problems for autonomous vehicles in 6 Degrees of Freedom (DOFs), with monodirectional actuators and whose mathematical description includes uncertainties and disturbances. Quaternion-based guidance rules are proposed for attitude and position control at the kinematic level. The actuation system consists of seven monodirectional jets, suitably...
A new small-sized autonomous surface vehicle actuated by a water-jet has been developed at INESC TEC for search and rescue of victims at sea. This paper describes the vehicle main components and presents the control and guidance laws governing the motion and enabling it to perform line-following and target tracking missions. Results from field trials are presented, demonstrating the capabilities and...
Autonomous underwater vehicles (AUVs) is a field of growing interest due to its potential applications in ocean exploration, surveillance, inspection of undersea equipment, defence, and finding sunken ships, aircraft and other lost artifacts. This paper addresses the challenges involved in designing the controller for an open-frame AUV that is described by the complex nonlinear kinematic and dynamic...
An adaptive integrated guidance and control scheme is developed for the entry phase of winged RLV. The reference profiles are generated off-line using constrained optimization techniques to take care of all possible variations in initial conditions and path constraints. Lateral and longitudinal guidance commands are generated in-flight with the help of stored reference profiles to meet the boundary...
In this work we present a combined planning and control strategy to let agile autonomous robots navigating in real-world populated environments by means of range limited sensors. In order to reduce the computational cost of obtaining a dynamically-feasible path, the proposed solution relies on a simple way-points generation subject to geometrical constraints. Conditions ensuring feasibility of the...
Store-carry-and-forward is extensively used in vehicular environments for many and varied purposes, including routing, disseminating, downloading, uploading, or offloading delay-tolerant content. The performance gain of store-carry-and-forward over traditional connected forwarding is primarily determined by the fact that it grants a much improved network connectivity. Indeed, by letting vehicles physically...
The growing interest on service robotics with the use and exploitation of unmanned aerial vehicles has revealed important issues related to safety and fail prevention during navigation, and recent research has been devoted to understand and modeling the breaking of 1, 2 or even 3 motors. In this context, the present paper investigates the dynamics of an unmanned aerial vehicle of quadrotor type using...
Flight tests of prototype UAV systems can be restricted by spatial constraints and they may bring risks of damage due to failures. Motivated by these, we presented a simulation approach based on Robot Operating System (ROS) and Gazebo. Unlike other state-of-the-art quadrotor simulators, we implemented the dynamics model of the UAV in ROS to achieve high fidelity behavior of the UAV. A hierarchical...
A novel sampling-based receding horizon control strategy that guarantees collision-free navigation for a class of aerial robots is the topic of this paper. The proposed approach combines the concepts of receding horizon control and sampling-based navigation strategies in order to derive a model-based control framework, which respects input and state constraints, and achieves avoidance of any known...
In this paper we present a prototype system that aids the operator of a Personal Air Vehicle (PAV) by actively monitoring vehicle surroundings and providing autonomous control inputs for obstacle avoidance. The prototype is developed for a Personal Air Transportation System (PATS) that will enable human operators with low level of technical knowledge to use aerial vehicles for a day-to-day commute...
An optimization-based path-following control scheme for the lateral control of a nonholonomous vehicle is proposed. It is formulated as a nonlinear model predictive controller. The penalty function is chosen in a way that the result of the optimization is conceptually similar to the output of a traditional “Follow-the-Carrot” or “Pure Pursuit” approach as long as no constraints are active. This allows...
In the present paper, a hybrid architecture based on multi-agent systems is proposed, where it is included a module for formal evaluation. This module, allows the processes verification involved in the level/layer/environment steps. It is also developed a methodology for trajectory tracking based on the generation of a reliable virtual space, on which the navigation takes place under operative conditions...
We present a novel framework for collision free assisted navigation of a semi-autonomous vehicle in complex unknown environments with moving and steady obstacles. In the proposed system, a semi-autonomous vehicle is guided by a human operator and an automatic reactive navigator. The autonomous reactive navigation block takes control from the human operator in situations where there is the danger of...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.