L.A.S.E.R. - Lunar Automotive Sun Energy Redirector

Last crawled date: 1 year, 11 months ago

Characteristics
Meet the “Lunar Automotive Sun Energy Redirector”!
L.A.S.E.R. is a tele-operated heliostat system attached to a Rocker-Bogie that is designated for concentrating/redirecting sunlight, illuminating of shadowed areas and thermal management.
Heliostat dimensions: while packed: 1.62 m x 1.2 m x 0.36 m
while deployed: 8.28 m x 1.7 m x 0.13 m
Overall dimensions: while packed: 1.5 m x 1.36 m x 1.99 m
while deployed (standard position): 8.28 m x 3.04 m x 1.99 m
Weight: Heliostat system: 115 kg
Total weight: 475 kg
Reflective area: 1.7 m^2 x 6 = 10.2 m^2

Heliostat system
The architecture chosen for the system design is curtain folding type. 6 mirror panels are folded around a central photovoltaic panel (used while the system is deployed). To reduce the weight, the 4 mm thick reflective plastic sheet was chosen because they are thick enough to support their own weight. The system is operated by motorized hinges (6 pieces) that handle a set of metal sleepers on which the mirrors are installed.

Solar array
The heliostat include a large solar panel (1.32 m^2) that is used while the system is closed. While when deployed, a second photovoltaic is revealed in the center that take the role of the first. This array allows that, when it’s needed or in extreme cases, both can be used to convert energy at the price of two unused mirror panel.

Guidance system
The guide system is composed of 2 axes of rotation perpendicular to each other that allow the orientation of the heliostat system. Taking into account the mass of the system, it was opted for the variant of servomotors that operate a cycloidal reducer, thus offering a benefit regarding the exact accuracy of the system positioning (considered necessary for precise illumination of targets or areas at a greater distance).

Sun tracking
Sun tracking is made via 4 individually encapsulated photoresistors. By regional stimulating of light, the sensor has the ability to locate the direction of origin of the light rays. The sensor is also equipped with its own pitch-rotation axis that allows its perpendicular positioning in the direction of the light source, while the heliostat system can individually change its angle of attack.

External power connector
The system allows continuous charging at the dock station through the 2 embossed strips arranged horizontally on the back of the rover. The docking station is also provided with 2 such horizontal contacts arranged at the same height as the others, so the rover can come into contact with them and thus the power supply can be achieved while it is not deployed. It should be mentioned that the contacts from the docking station are provided with springs that allow a state of continuous pressure exerted towards the supply contacts, eliminating the risk of unwanted interruption of the charging process.

Disclaimer
Even if the theme of the contest was not focused on making the rover model, I took the liberty of designing my own system. It is worth mentioning that the model belongs entirely to me and is made by me. If I had more time I could have prepared a fully functional model with the entire internal organological structure.

Recap

Each actuator and gear is provided with its own insulation jacket with a thickness of 10 mm, the material used being the aerogel (given its own density). This is easily seen in cutaway renderings highlighted with a blue stripe.

In order to reflect as much light as possible to an area as far away as possible, it was decided to choose a rigid reflection surface. A flexible surface requires high tension and even with this, it will not be possible to rise to the quality and quantity of reflection of a rigid planar surface.

Given the large reflective surface and the not so great storage space (taking into account the fact that that volume must be shared with the displacement system) it was considered the best mirror storage system as folding curtains.

In order to keep the assembly of mirrors as simple as possible, a system has been designed to fold as few times as possible (to reduce the increase in the number of actuators and implicitly to reduce the complexity of the model).

The ability of individual focusing of the mirrors in a concave type assembly, in combination with the high precision of the orientation of the system allows a much greater distance of action compared to any other system.

Additionally, the centers of mass of the system were calculated in the most unfavorable conditions: the heliostat system extended horizontally, in front and side of the rover (particular case, that has no application in normal use) and the results are satisfactory: The rover can operate the heliostat system complete safety located on an inclination of 32 °. Obviously, this value increases in regular use.

Also, the height at which the system is positioned while it is open, provides enough ground clearance for the deployment and use of the heliostat system, leaving enough room to terrain unevenness (1.3 m)

In order to prevent the interference of the lunar dust with the mechanical systems, it was avoided the use of any translation systems (telescopic rods, ball screw guidance system, linear roller bearings, linear motors, etc.). Thus, all the operating methods used are exclusively rotational axes (which allows a better sealing against external dust)