Unicycle Robot Prototype – Engineering Design Fair 2022

Project Category: Mechanical

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About our project

The purpose of this project is to build an autonomous unicycle robot prototype capable of straight-line motion and standing through self-stabilization with the primary use of a three-dimensional dynamics equation developed for a unicycle model.

We hope that we can bring this kind of unicycle into industry in performing some little work and completing tasks within a more limited space. The hope is that by importing this kind of unicycle into the market, companies can reduce the labour needed and lower the manufacturing cost. On the other hand, the theory behind this specific type of unicycle can also contribute to many other fields.

The project was originally launched in 2019 with the attempt of using PID control, however, the progress was slowed down due to the covid-19 outbreak. This year, the project restarted with the complete 3D equations model built by our sponsor Dr.Budiman and an impressive prototype was built by the team!
The prototype cost: $1,200 + GST.

Meet our team members

Borden Li
Mahmoud Elmalawany
Mohamad Aly Sherif
Victor Edet
Yuxiao Lin
Ziyuan Tang

Details about our design

CONCEPTURE DESIGN:

Prototype Model: Designed in Solid-works to create a symmetrical unicycle model without the features of flywheel.

Simulation: MATLAB prediction of the unicycle motion plan and required torques by using the reverse kinematics theory. (including stand still & move along a straight line)

Control System: Arduino program to control two screw motors to achieve pitch and roll motion respectively and the hub-motor to achieve spin motion with all motors in synchronized motion to achieve standing.

Manufacturing: Procurement and assembly of the BudiBot by selecting the satisfactory equipment, assembling based on the Solid-works model and testing for the demanded features. (including :FDM printer, Electrical Bike Hub Motor, Screw Motor, Lead-acid batteries, wiring etc.)

WHAT MAKES OUR DESIGN INNOVATIVE

Although there is already various kinds of unicycle in the market now, and some labs have also invented their own unicycle robots. The special and highlight point of our unicycle robot is that we are using a new theory which has never been explored before. The unique 3D kinematic equations were built and verified by our project sponsor Dr.Budiman. He has spent the past two years researching and developing the equations. From the backward and forward calculations we are now confident with the equations.

WHAT MAKES OUR DESIGN SOLUTION EFFECTIVE

Compared the design from our team to previous one, we add more stable structure and ensure the symmetry of the model to better approach the self-stabilization function. And this year, we introduced the MATLAB simulation to predict the kinematics performance of the unicycle robot. The sinusoidal motion plan was assumed for Budibot, by doing the backward and forward simulation then we can assist the control system and make the motion into reality. The required torques for each motor can be generated by the simulation and this helped us fulfill the requirement of our attached motors. The solid and trustable equations and simulation results makes our design unique and makes our design solution effective.

HOW WE VALIDATED OUR DESIGN SOLUTION

Our design solution will be validated by several testing assignments:

Stage One: Manually Held BudiBot

Check if MPU6050 sensor correctly outputs desired angles
Response of screw motor to incline in the roll direction
Response of hub motor to incline in the pitch direction

Stage Two: Self-supported BudiBot

Maintain balance for 10 seconds (the angles of movement should within 10 degrees)

Stage Three: Self-supported Linear moving BudiBot

Keep balance when the unicycle starts/stops and maintain at constant speed
Move 3 meters forward without falling ( Moved to the summer project )

FEASIBILITY OF OUR DESIGN SOLUTION

Trustable equations models with resulting torques that can be achieved by motors.
Functional design similar to a unicycle model and improvement in the geometry symmetry.
Arduino control system was compatible with all motors and delivered reliable results for improved testing.
Manufacturing /procurement with high repeatability and overall inexpensive.

Partners and mentors

We want to thank the many people who helped us with this project. Our sponsor Dr.Budiman provided the project funding and supported us whenever we came across an issue. Our mechanical engineering professor Philip Egberts and teaching assistant Tom Mathias guided us through the process with patience and great advice. And, our friend Khaled Elmalawany from electrical engineering validated the control system code.

Our photo gallery

References

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