The sun tracker is made up of a Firewire camera, fisheye lens, and a dark neutral density filter. It has a view of the entire sky. If the sun is visible, the sun tracker can measure the direction to the sun very accurately. By combining a measurement of the direction to the sun from the sun tracker with a measurement of the direction toward "down" from an inclinometer, the sun tracker can estimate the orientation of the rover. The sun tracker provides an orientation estimate that is independent from the compass. This is important for places that have no magnetic field (like the Moon) or in an unreliable magnetic field (like Haughton Crater).
There is also a wireless "E-STOP" button that would be used by an astronaut in emergencies. And an onboard "hard E-STOP" in the sensors determine danger to the robot or a human.
The K10 runs on custom, embedded software on a dual-core Linux laptop.
Programmable language used is C, C++, and JAVA.
The K10 uses 20 laptop computer lithium-ion batteries to power its four-wheel-drive, all-wheel steering equipment and sensors. The charger is similar to the Ocean Server model XP-08S Mini Battery Management Module shown below.
The K10 Rover power management module manages up to eight smart Li-ion battery packs for up to 760 Whrs or battery power. Total automatic operation with system level status data such as Time-to-empty, Time-to-full, current, voltage, etc.
(Source: Ocean Seas)
Fong told us that in an oxygen-rich atmosphere like the International Space Station (ISS), smart share devices actually use AA batteries. iPads now use rechargeable batteries on the ISS.
Mars Spirit and Opportunity both use solar-powered energy. The high amount of dust on the planet is a problem in that it accumulates on the solar arrays. A clever solution, says Fong, is to orient the rovers toward the periodic wind gusts that are prevalent on Mars.
Robots in deep space or on long missions would need radio-isotope-powered systems.
In 2009/2010, Team Induct-Us has designed an inductive charging system for the K10 Lunar Rover. The purpose of the project was to design and build an inductive charging circuit. This idea is something that was completely new to the K10 project and is something that is required for actual use of the rover on the moon. Since Ames had to manually plug in the batteries, an isolated system was important toward having an autonomous rover. There also was no other system like it at the time and there were plans to refine it in the future. The design output was an unregulated voltage to the battery management system. This variation was not one that was ideal, but one that was appropriate for the management system at that time.
The inductive charging system had to be able to charge the K10's batteries, Ocean Server Intelligent Battery System (IBPS), fully. The system needed to be integrated in the current K10 rover at Ames, autonomously run, and have desired 60 percent power transfer efficiency.
The project was split into two separate sections: mechanical and electrical. The mechanical consisted of an arm design, charging station structure, and docking aids. The electrical consisted of appropriate components for the charging circuit, proper feedback, and power circuit design. The arm designs and station were tested for ease of use, complexity, and price. The charging circuit has been tested for power requirements and optimum power transfer efficiency.
Fong told us that the mantra is reliable, robust, and safe systems. Do not injure external things or the robot. There are electronic, software, and mechanical safeguards that maintain safety.