Autonomous ground vehicle navigation requires the integration of many technologies such as path planning, position and orientation sensing, vehicle control, and obstacle avoidance. The work presented here focuses on the control of a nonholonomic ground vehicle as it tracks a given path. A new path tracking technique called ''vector pursuit'' is presented. This new technique is based on the theory of screws, which was developed by Sir Robert Ball in 1900. It generates a desired vehicle turning radius based on the vehicle's current position and orientation relative to the position of a point ahead on the planned path and the desired orientation along the path at that point. The vector pursuit algorithm is compared to other geometrical approaches, and it is shown to be more robust, resulting in more accurate path tracking.

This paper describes how the functionality of the DoD Joint Architecture for Unmanned Systems (JAUS) was expanded by developing experimental components related to off-line and reactive path planning and world modeling. JAUS defines a set of reusable components and their interfaces. In order to ensure that the JAUS architecture will be applicable to the entire domain of unmanned mobile systems, the following four characteristics were considered throughout its development: vehicle platform independence, mission isolation, hardware independence, and technology independence. The new experimental components described in this paper have these same characteristics.Existing JAUS components readily allow for autonomous path tracking. In this work the JAUS Version 3.0 Global Path Segment Driver, Global Pose Sensor, Velocity State Sensor, and Primitive Driver components were utilized for that task. What is described in this paper is the development of the following new experimental components: World Model, Sensor Arbiter, and Path Manager. The functionality and interface messages of each of these components are presented, followed by a discussion of the performance of the overall system.

No abstract

No abstract