Let's Connect
Novel mechanism for precise docking and In-space assembly using track based solution
Summary
In docking we have used a novel optimized design of delta robot and a robotic arm with end-effector attached with spherical joint and a unique mechanism has been developed using universal joints. April tags technique has been incorporated into our design.In order to facilitate In-space assembly we need two objects, one a space station(Track) which holds and controls the motion of parts in space and two a key attached to the part(which should be assembled) to facilitate a connection between part and track. ones the parts are connected to the Track, ref1,ref3 and ref7(check reference column) methods are used to connect all the parts.
How We Addressed This Challenge
In-Space Assembly
We developed a space station and a key, the main motto of the space station is to hold the parts in space and control their motion in 4 degrees of freedom, by controlling the movements of the parts in more than 3 degrees of freedom we can easily assemble them. Key is used to attach the parts to the space station, so irrespective of what you want to assemble you can just add a key to any part and attach it to the space station, after that there are so many ways to assemble these parts in space some of these ways are mentioned in the reference section.
The importance of this mechanism was it doesn’t depend on what you want to assemble so there are no restrictions for assembling.
We hope to have this mechanism work in real life and help us in future to construct or assemble any entity which would help the mankind to explore the space.
Docking
The current methods of docking involve a 6DOF Stewart like platform which aligns and orients itself according to the passive ring on the ISS. Due to the orienting motions asymmetric loads are generated on the legs and hence a need for torsional springs. We have modified the docking system by using a delta robot type manipulator which provides 3 axis translatory motion on the satellite side and rotational motion from a robotic arm attached to the base part.
Using the delta robot makes it more cost efficient and easier to develop. To align each other in the right orientation, April tags are used. Once this has been achieved approximately and at the specified distance, the rods with spheres(that can roll) at the end, present on the end effector of the satellite, align themselves perpendicular to the end effector. At the same time hollow, frustum like structures protrude out of the end effector of the robotic arm. As they come closer the spheres come in contact with the hollow frustum and move up. The frustum like shape is to ensure accurate positioning. After this the male gets locked with the female and is gets attached to the base part as the protruding rods containing the hollow frustum move backward into the end effector.
How We Developed This Project
The Earth is not a permanent shelter for humans, so there's a need to find alternative locations to exist which includes other planets and moons. Further improvements and technologies are required in the areas of In-space assembly and docking to facilitate construction of large structures that can help support mankind. Hence, finding easier and efficient solutions would plant the seeds for rigorous space exploration.
We have explored different mechanisms that are used in In-space assembly and docking, later found their pros and cons and tried to overcome them. We also developed new mechanisms for In-space assembly and docking .
Software Used:
1) PTC Creo
2) MATLAB
Coding Languages
1) JAVA
The only problem we faced was we hadn't got access to information regarding mechanisms that were used for In-space assembly in the construction of ISS.
We have successfully designed a prototype for our approach and were also able to simulate some part of it. If enough resources and time were provided, further simulation of models would be developed to better understand and validate our solution enabling us to build a real life model, if simulation models show positive results.
The prototypes as well as simulation codes are shared on a open GitHub profile. Please find attached the link below.
How We Used Space Agency Data in This Project
We have used NASA's technologies for finding various mechanisms and ways which are already used in this field of In-space technology and Docking.
NASA resources have helped us in gaining understanding about existing mechanisms of docking and studying this thoroughly helped us in developing a mechanism on our own. Some resources were also helpful for building a base in the areas of mechanisms for precise positioning.
For perfect alignment of entities while assembling, we used the technologies developed by assemblers (a NASA project ),and solution developed by KISS(a Caltech university project)
Project Demo
Data & Resources
1) Belvin, W. K., Doggett, W. R., Watson, J. J., Dorsey, J. T., Warren, J. E., Jones, T. C., … Bowman, L. M. (2016). In-Space Structural
Assembly: Applications and Technology. 3rd AIAA Spacecraft Structures
Conference. doi:10.2514/6.2016-2163
5) https://www-robotics.jpl.nasa.gov/tasks/showTask.cfm?FuseAction=ShowTask&TaskID=284&tdaID=700088
6) https://april.eecs.umich.edu/software/apriltag
7) https://kiss.caltech.edu/techdev/largestructure/largestructure.html
8) Automated Rendezvous and Docking of Spacecraft, Author: Wigbert Fehse, Published by Cambridge Aerospace Series.