Smaller autonomous underwater vehicles that use differential thrust for surge and yaw motion control has the advantage of low cost and, at the same time, increased ma­ neuverability in yaw direction. However, since such vehicles are underactuated vehicles, design of an autonomous control system that enables the vehicle to autonomously track a predefined trajectory is challenging. In this paper,...

This paper investigates the synthesis of a non-linear spatial lookahead controller for path tracking of Ackerman-steered autonomous vehicles. Controller tuning is performed using stability results and optimization techniques. Controller performance is analyzed when the vehicle follows different paths at different speeds. Finally experiments have been conducted using the ROMEO 4R autonomous vehi...

Most autonomous vehicles use GPS to determine vehicle location and heading. Using GPS for vehicle autonomous driving posts a few challenges. It does not look far ahead of the vehicle and requires frequent adjustment of vehicle heading. This results in an unstable control system and increases the chance of unstable driving behavior. Unlike this kind of passive or reactive control system, human d...

In this paper, an intelligent navigation system for an unmanned underwater vehicle powered by renewable energy and designed for shadow water inspection in missions of a long duration is proposed. The system is composed of an underwater vehicle, which tows a surface vehicle. The surface vehicle is a small boat with photovoltaic panels, a methanol fuel cell and comm...

This paper describes the steering controller of the CajunBot II, an autonomous vehicle designed for the DARPA Urban Challenge. The autonomous vehicle is a modified Jeep Wrangler Rubicon equipped with INS/GPS for localization, three sets of sensors and three single board computers. The control objective is to make the lateral error at a certain point ahead of the vehicle zero. The distance of th...

A fuzzy logic based general purpose modular control architecture is presented for underwater vehicle autonomous navigation, control and collision avoidance. Three levels of fuzzy controllers comprising the sensor fusion module, the collision avoidance module and the motion control module are derived and implemented. No assumption is made on the specific underwater vehicle type, on the amount of...

It is challenging to develop a control algorithm that uses only one sensor to guide an autonomous vehicle. The objective of this research was to develop a control algorithm with a single sensor for an autonomous agricultural vehicle that could identify landmarks in the row-type plantation environment and navigate a vehicle to a point-to-go target location through the plantation. To enable such ...

Development of autonomous underwater vehicles (AUVs) which meets the design constraints and provides the best hydrodynamic performance is really an important challenge in the field of hydrodynamics. In this paper a new profile is used for designing the hull of AUVs. The nose and tail profiles of an AUV using presented profile is designed such that it can properly consider the length constraints...