Problem

At the Apollo 11, the astronauts had only two hours and twenty minutes to do their required activities and collect the dreamed samples from the moon. With eight minutes to finish the time, Neil Armstrong had not collected the samples. This work required carefully taken photos and notes of the context of each sample while handling pre-numbered bags [1].

A recent Georgia Tech [2] study reported that every Apollo lunar EVA was used longer than it was planned, except one. When this happens, astronauts use more of their suits life sustaining supplies than originally designed. Georgia Tech described cases of 20% over the expected limit in the consumption of supplies.

There already exists unmanned rovers, however these devices present some limitations as size, composition - a great number of sensors and tools, and little or no flexibility [3].

Solution

We developed the Lunar Centipede Robot - LCR 1135, a concept of autonomous reconfigurable modular robot, inspired on centipedes with the objective to assist astronauts in the collection of samples on the moon. We created the name LCR 1135 inspired by the distance between the stars Alpha Centauri A and Alpha Centauri B - 11 and 35 AU.

How it Works

Our centipede robot is formed by coupling of sections. Each section is composed by legs that move using the mechanism developed by Theo Jansen [4]. One section is formed by a deployable part, for example scissor-like mechanisms or origami mechanisms, with the objective to storage the robot in a reduced space.

The differential of our project is based on the reconfigurability and modularity of our concept by coupling sections, with the possibility of changing the number of sections and connecting the modules required for each mission.

The figure below shows two sections coupled and the movement of the legs.

Now, on the figure below we show these two sections carrying two modules.

The figure below shows one section folded for storage.

One example, to facilitate the visualization of the mechanism used is the umbrella, which folds and is stored. The mechanism we are showing is formed by scissor-like elements. The objective of the reconfigurability shown is to allow the robot to be taken to space in a compact manner, decreasing the area and volume required for this robot in a spacecraft, thus decreasing the costs related to taking the robot into space. The mechanism developed is based on scissor-like elements, however different classes of deployable mechanisms can be used, such as origami mechanisms which are already used in aerospace applications.

On the following animations is possible to visualize the movement of the legs and also the reconfigurable mechanism decreasing in size for storage.

When in a mission, the astronaut assembles the number of sections according to the work required by the robot. After selecting the number of sections, the astronaut assembles the desired modules, selecting sensors, storage spaces, robotic arm, etc. With the robot composed by sections and different modules, it is sent to the mission: mapping of soil characteristics, collection of samples, etc.

We have underneath examples of configurations of modules for a trajectory mapping and soil survey, consisting of an A.I. module for the trajectory planning, data storage, communication; a module with a fluorescent x-ray for chemical mapping of the soil traveled by the robot; a geo mapping module for registering detailed data of the region traveled by the robot.

In this other example, for a different mission, the robot is formed by: modules for sample storage, a module with a robotic arm for sample collection and a module with an A.I.

Why legs?

Although legged robots are more complex than their wheeled counterparts, they perform better on uneven terrain, avoiding footholds that wheels cannot [5][6].

There are many types of legged robots with different types and number of legs. We chose the Theo Jansen mechanism as it is compact and commonly used with one input, such as a motor, to actuate a great number of legs. However, dependending on the operations different types of leg mechanisms can be chosen.

How does the robot moves?

Each module of the robot is to be fitted with solar panels for energy generation and batteries for an increased autonomy for the robot. The movement of the robot is to be done by an electric motor and an axle that transmits torque to the legs. By coupling new sections, the driving axle of each section is coupled to the driving section of the previous section. The robot makes turns by using a system similar to the locking differential present in some vehicles, by locking one part of the differential, the rotation is passed only to one of the sides of the robot. The legs are equipped with linear displacement transducers to ensure that the legs are correctly moving. The robot is also equipped with IMU sensors to prevent roll-over.

Benefits

• Safety of the astronaut and the mission.
• Optimization of the astronaut’s time when doing extravehicular activities such as sample collection.
• Easier maintenance of the robot due to is modularity, which means, if an important component fails, the robot is not discarded, that module or section is replaced by another and the robot can continue working.

Data Sources

We use NASA open data for:

• Understanding how the astronauts extravehicular sample collection activities in the moon surface [2] and which are the challenges and limitations faced.
• Mapping the lunar terrain - geography and geology [7][8][9] - for an integrated A.I. that will begin the mission with a normality model and will explore new environments and will build a new normality model based on it’s own observations. The A.I. will also enable the data collection prioritization, balancing other needs, as power source or limited data storage [10].
• Determining the types of instruments required in sorting samples types when surveying the characteristics of the soil, with the objective of identifying and characterizing rocks or sediments [11].

Technological Resources

Prototype design: SolidWorks.

Types of sensors that can be used in modules [12][13]:

• Inductive sensor
• Capacitive sensor
• Photoelectric sensor
• Fiber-optic sensor
• Laser sensor
• Ultrasonic sensor
• Magnetic sensor
• Linear Variable Differential Transformer (LVDT)
• Pressure sensor
• Imaging sensor
• Photoelectric barrier sensor
• Full-spectrum autonomous sensor
• Fluorescent x-ray sensor
• Displacement sensor
• Vision sensor

Communication [14]:

• Deep Space Network (DSN)
• Global Positioning System (GPS)
• Near Earth Network (NEN)
• Space Network (SN)

Simultaneous Location and Mapping:

• Spectrum-Scan LiDAR (3D LiDAR) [15]

Team

Gabriela Barreto - is a specialist in the development of technological innovation projects and is passionate about acceleration of innovative startups. Linkedin: https://www.linkedin.com/in/gabriela-barreto/

Matheus Modro Krueger - is a student of software engineering and is passionate about data.

Otavio Murilo Rau - is studying Production Engineering and a member of a university extension project focused on innovation, and is passionate about innovation. Linkedin: https://www.linkedin.com/in/otavio-rau-284584196

Rodrigo Luis Pereira Barreto - is a Mechanical Engineer, PhD candidate researching robotics focused on mechanism design and mechanisms design methodology and is passionate about origami and reconfigurable mechanisms. Linkedin: https://www.linkedin.com/in/rodrigolpbarreto

Vitor Kuckenbecker Donini - is a student of Control and Automation Engineering and is passionate about sensors.

References

[1] https://www.magellantv.com/articles/moon-work-was-hard-work-apollos-astronauts-didnt-have-it-easy

[2] https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20170007261.pdf

[3] https://mars.nasa.gov/mars2020/mission/rover/sample-handling/#Collecting-Samples

[4] Jansen's linkage is a planar leg mechanism designed by the kinetic sculptor Theo Jansen to generate a smooth walking motion. Jansen has used his mechanism in a variety of kinetic sculptures which are known as Strandbeesten (Dutch for "beach beasts"). https://www.strandbeest.com/

[5] https://www.online-sciences.com/robotics/legged-robots-features-types-uses-advantages-and-disadvantages/

[6] https://newatlas.com/space/walking-moon-rover-spacebit-uk/

[7] https://moon.nasa.gov/

[8] https://www.hq.nasa.gov/office/pao/History/alsj/tools/Welcome.html

[9] https://www.lpi.usra.edu/publications/books/lunar_sourcebook/pdf/LunarSourceBook.pdf

[10] https://mars.nasa.gov/news/2884/ai-will-prepare-robots-for-the-unknown/

[11] https://msl-scicorner.jpl.nasa.gov/Instruments/CheMin/

[12] http://www.engerey.com.br/blog/tipos-e-aplicacoes-de-sensores-na-industria

[13] https://www.keyence.com.br/products/sensor/photoelectric/lr-w/index.jsp

[14] https://www.nasa.gov/directorates/heo/scan/communications/policy/GPS_Utilization.html

[15] https://geoslam.com/what-is-slam/