Sensing and Actuation: Lunar Zebro Rover Deployment System
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Abstract
The Lunar Zebro rover is a nano rover designed by student research team Lunar Zebro at the Technical University of Delft. This rover will be sent to the lunar surface to conduct scientific experiments. In order to protect the rover during transit and facilitate successful deployment onto the lunar surface, a rover deployment system was designed.
This thesis describes the design of the sensing and actuation part of the rover deployment control system. The thesis details the design of a system which is able to deploy 4 Non-Explosive Actuators by means of sequentially supplying more than 4A for 50ms to each NEA. This sequence is inhibited by a physical connection to the rover by means of an umbilical cord which can be overridden when the rover and microcontroller send an override signal at the same time. The system contains a heating element and two temperature dependent relaxation oscillators that can be used to regulate the temperature. Thermal regulation can function independently of a digital control system, but can also be managed by the microcontroller. In the case that the microcontroller experiences failure, the NEA activation sequence can be initiated by two control signals from the lander, to which the deployment system is attached.
The system has not been physically tested, but has been verified in simulation. The combination of all these subsystems uses a peak power of 1.1W in simulation.
A test printed circuit board was designed to incorporate the complete rover deployment control system. This board can be used to physically simulate the deployment of the four non-explosive actuators by means of glass fuses. The board also allows any equivalent NEA model to be used in order to verify the limits of the system.
The system meets all functional requirements in simulation. Future work regarding the design entails physical testing of the PCB and the resolution of two major vulnerabilities, namely its reliability on the stability of the lunar lander’s 28V supply as well as its inability to handle excessive thermal energy.