JAUS - Software Components

Primitive Driver: The Primitive Driver component provides open loop control for basic vehicle mobility functions including operation of common platform devices such as the engine and lights. This component does not imply any particular platform type such as tracked or wheeled or air or ground, but describes mobility in six degrees of freedom using a percent of available effort in each direction. Additionally, no power plant (gasoline, diesel, or battery) is implied and the component functions strictly in an open loop manner.

Vector / Velocity State Driver: The vector driver is responsible for following a preset vector in global or local coordinates by providing closed loop heading and velocity control for the platform. The Vector/Velocity State Driver uses information from the Global and Local Pose Sensor components to generate commands for the Primitive Driver to execute.

Global / Local Waypoint Driver: The function of the Global/Local Waypoint Driver is to determine the desired wrench effort or steering effort of the platform given the desired waypoint(s), travel speed, current platform pose and current velocity state. Single or multiple waypoints (the desired position and orientation of the platform) can be sent via the Set Global Waypoint message. The Global / Local Waypoint Driver component use input from the Global and Local Pose Sensor components, and optionally the Velocity State component to compute the appropriate speed, heading, and/or wrench effort to be sent to the Vector/Velocity State Driver or Primitive Driver.

Reflexive Driver: The Reflexive Driver component is responsible for low-level obstacle detection and avoidance to ensure vehicle safety. This component is typically used to filter wrench effort commands being sent to the Primitive Driver by higher level components such as the Vector, Velocity State or Global/Local Waypoint Drivers. The Reflexive Driver only modifies the target wrench effort enough to keep the vehicle from hitting obstacles, and otherwise, acts as a pass-through for wrench effort messages.

Global Pose Sensor: The function of the Global Pose Sensor is to determine the global position and orientation of the platform. The Report Global Pose message provides the position and orientation of the platform. The position of the platform is given in latitude, longitude, and elevation in accordance with the WGS84 standard. The parameters roll, pitch, and yaw are also provided to define the orientation of the vehicle when appropriate sensors are available.

Local Pose Sensor: The Local Pose Sensor has the responsibility of computing the local pose of the vehicle. This is currently with reference to the vehicle when the component is started. Local pose is currently computed in X, Y, Z, Roll, Pitch, and Yaw. As this component makes use of encoders, which are subject to slip, and gyros, which are subject to drift, the accuracy of the local pose estimate will degrade over time. Typically, with high-traction tires/treads and fiber optic gyros, on non-muddy terrain, accuracies of about 1% of distance traveled are observed. This component is integrated with the Velocity State component, as both require the same sensor information (gyros, encoders).

Velocity State Sensor: The Velocity State Sensor has the responsibility of reporting the instantaneous linear and angular velocity of the platform. This component is integrated with the Local Pose component, as both require the same sensor information (gyros, encoders).

Visual Sensor: The Visual Sensor component provides a common interface to one or more cameras that are on the vehicle. It provides a common interface to all camera types – analog, Firewire, USB, etc. – and can support multiple cameras (optionally on pan-tilt units) at the same time. The Visual Sensor provides message in M-JPEG format, typically via a JAUS Service Connection.

World Model Knowledge Store: The JAUS World Model Knowledge Store is not a separate software program (usually), but rather a database that is part of JAUS components that sense the environment, either directly (laser or radar sensors) or indirectly (DTED maps, etc.) This customizable database supports both vector and raster data and uses the JAUS World Modeling Query and Report messages for data insertion and retrieval.

Primitive Manipulator: The Primitive Manipulator component provides open loop control of robotic arms and manipulators that are present on the vehicle platform. It can be controlled via our standard operator control unit, or via an interface which uses the proposed JAUS Payload standard.

System Commander: The System Commander functions as the robotic system Operator Control Unit (OCU) and provides a graphical user interface which provides control and status information about platform as well as the individual JAUS components. The System Commander allows a user to graphically view the vehicle’s position, query the states of the various JAUS components, send state transition messages to the components, and create more complex missions for the vehicle to execute. A screen shot of the OCU is shown in the figure below.