Basic Navigation Tasks Research Articles

Stereo visual odometry in urban environments based on detecting ground features

Autonomous vehicles rely on the accurate estimation of their pose, speed and direction of travel to perform basic navigation tasks. Although GPSs are very useful, they have some drawbacks in urban applications that affect their accuracy. Visual odometry is an alternative or complementary method because provides the ego motion of the vehicle with enough accuracy and uses a sensor already available in some vehicles for other tasks, so no extra sensor is needed. In this paper, a new method is proposed that detects and tracks features available on the surface of the ground, due to the texture of the road or street and road markings. This way it is assured only static points are taken into account in order to obtain the relative movement between images. A Kalman filter improves the estimations and the Ackermann steering restriction is applied so the vehicle follows a constrained trajectory, which improves the camera displacement estimation obtained from a PnP algorithm. Some results and comparisons in real urban environments are shown in order to demonstrate the good performance of the algorithm. They show the method is able to estimate the linear and angular speeds of the vehicle with high accuracy as well as its ability to follow the real trajectory drove by the vehicle along long paths within a minimum error.

An Analysis of Automated Guided Vehicle Standards to Inform the Development of Mobile Orchard Robots

Abstract: This paper aims to leverage knowledge and experience, gained from the well-established Automated Guided Vehicle (AGV) industry, to highlight key hazards and solutions that may be considered in the risk assessment and risk reduction of large autonomous mobile service robots in orchards. There are notable differences between orchard environments and the warehouses or factories, where AGVs operate, including the presence of uncontrolled growth, exposure to the weather as well as the slope, softness, cluttered and undulating nature of terrain in orchards. However, there are also many similarities in the technologies used, the basic navigation tasks that have to be performed and the nature of the hazards that arise. This paper discusses these similarities and differences in relation to key parts of AGV standards, EN 1525:1997 and ANSI/ITSDF B56.5-2012.

Experimental testing of a cooperative ASV-ROV multi-agent system

Abstract: The development of versatile and cost effective robotic tools for exploration and intervention in the underwater environment is presently a topic of interest in marine engineering. A viable, efficient solution is given by robotic platform that couple autonomous surface vehicles and unmanned underwater vehicles in integrated structures with various levels of cooperation. In this paper, we describe a number of field tests on the surface component of a robotic platform consisting of an autonomous surface vehicle that can automatically deploy and recover a small remotely operated vehicle. The aim of the tests are to assess the main functionality of the navigation, guidance and control system of the vehicle in relation to basic navigation tasks, both in supervised and in fully autonomous mode. In particular, in order to assure cooperation with the deployed remotely operated vehicle, the ability to track a target is considered.

A longitudinal evaluation of hands-free speech-based navigation during dictation

Despite a reported recognition accuracy rate of 98%, speech recognition technologies have yet to be widely adopted by computer users. When considering hands-free use of speech-based solutions, as is the case for individuals with physical impairments that interfere with the use of traditional solutions such as a mouse, the considerable time required to complete basic navigation tasks presents a significant barrier to adoption. Several solutions were proposed to improve navigation efficiency based on the results of a previous study. In the current study, a longitudinal experiment was conducted to investigate the process by which users learn to use hands-free speech-based navigation in the context of large vocabulary, continuous dictation tasks as well the efficacy of the proposed solutions. Due to the influence initial interactions have on the adoption of speech-based solutions, the current study focused on these critical, initial, interactions of individuals with no prior experience using speech-based dictation solutions. Our results confirm the efficacy of the solutions proposed earlier while providing valuable insights into the strategies users employ when using speech-based navigation commands as well as design decisions that can influence these patterns.