A pipe traversing robot

Abstract

The aim of this project was to design a manually operated robot that could traverse inside a hollow pipe and perform certain actions on its way. The robot was made in accordance to the problem statement that was mentioned in the event Inspiral On conducted during IIT Kharagpur's technical festival Kshitij. The aim of the bot was to "heal" the helix or the hollow cylinder for which certain points would be given, and at the same time dodge a certain number of obstacles. The bot has 3 Degrees of freedom and the entire mechanical designing was done on Autodesk Inventor

Arena

Pipe Traversal

The arena is given as below. The arena is a hollow cylinder with a pipe running through its center. The robot must be capable of travelling inside this hollow cylinder using this pipe for traversal.

Checkpoint

The check points are mounted on the periphery of the arena at the border. Dodging the arena and dropping certain checkpoints as one passes by adds points. There is no specific mechanism to combat this problem but a rotational movement on the bot to dodge the red ones and drop the others.

Cork

The cork when it gets pushed out of the helix carries extra points and is the highest scoring section of the arena. A DOF was dedicated to allow this radial movement of pushing the cork out of the helix.

Axial View of the Arena

Design

Traversal Mechanism

The Robot uses the central rod for traversing on the arena. The wheels are aligned 120 degrees from each other. Since the arena is 10% erroneous for the same we made it adjustable to gripping on the rod with the help of screws and clamps. The extra wood was removed to reduce weight thus instead of a circular board a triangular wooden board was used.

Axial Rotation for the check points

The arm of the robot was mounted on a concentric tube. The concentric tube is attached co-axially to a worm gear which was paired to a stationary but rotating worm. Thus the arm would rotate as the worm rotates. The arm is extended so as to make contact with the checkpoint. This was the best way to this problem as the worm offers the best radial gripping as compared to other gears.

Cork Pushing Mechanism

The cork pushing mechanism uses the frame of a CD Drive which is modified for translation along the cork's axis so as to push it out of the helix to score the point. For this, an RF Module connected to the a motor driver circuit helps in wireless control of the motor of a rack and a pinion pair(modified CD drive). On a single console with two inbuilt H- Bridges on the IC7293d one could bring it forth and back.

Team, and my role...

A total of four students of which I was a part were involved in the project. Being a mechanical engineering student, my major job was to design the bot and specifically work on the worm and worm gear designing and printing. Apart from that, I worked on the circuit of the cork pushing mechanism.

Our team won the third prize (Cash Prize of INR 9000) out of the over 200 teams that participated.
Fastest team in Round 1
Received a letter of commendation for the most innovative design

Picture Courtesy: Devang Darode

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