System Architecture
Computations Subsystem
Localization Unit
The robot localizes through fusing sensor measurements from the total station, IMU, and wheel odometry. These are fed into a EKF-SLAM algorithm to obtain the pose estimate of the rover. A local EKF and a global EKF were implemented. The local EKF only uses the IMU and wheel odometry. It drifts over time but is always continuous. This allows local planners to operate less problematically. The global EKF uses all 3 sensor measurements. It is much more accurate but is not always continuous. This may cause problems with local planners and is used for navigation.
External Infrastructure Subsystem
The external infrastructure comprises the total station, TX2 relay chip, LAN router, and an operations terminal. The robotic total station provides precise robot pose estimates and sends it to the TX2 relay chip. The chip processes the total station data and publishes to a ROS2 topic in our LAN network. The Jetson on the rover subscribes to this topic and receives pose updates. The operations terminal allows for seamless communication between the rover and mission control through the LAN network, and provides a user interface to monitor progress and receive updates.
Sensors Subsystem
To be updated once implemented.
Mechanical Subsystem
Wheel Assembly Unit
The current wheel being used is a pneumatic wheel. We have designed a rigid wheel to reduce wheel slippage and increase grip. A prototype is shown below:
Excavator Assembly Unit
The excavator assembly unit is used to push away sand to create a trail path. After going through several design iterations, we have finalized our design and is sent to be printed. A CAD design of our excavator assembly unit is shown below:
Actuation & Electronics Subsystem
To be updated once implemented.
Electrical Power Subsystem
The preliminary design of our electrical power subsystem is shown below:
