While there are many ways that CleanBot could be improved, we are proud to present our hard work. 

Presenting CleanBot with its various face:

Figure 1: Final product (CleanBot with its 8 eyes saying “Hello World!”

Figure 2: Front View (“Can you feel the stares~”)

Figure 3: Back and Side view with various components (“I’m Shy!”)

Swapping Mechanism

Video 1: Showing how a user would have to swap the cleaning mechanism.

Autonomous Motion

Video: Motion of the robot autonomously. The first part of the video shows the actual speed of the robot. As the video progresses, the video is sped up to not bore you. 

The cleaning robot uses an S -shape cleaning motion, which is the “most” efficient cleaning method available. While there have been research showing that long runs of Random Walk algorithm and S-Shaped walk would yield similar results as well as Random Walk providing slightly more efficient cleaning, S-shaped cleaning motion would require lesser correction and intervention, as well as having a more evenly spread out heat map as compared to Random Walk algorithm (Source 1)

Ultrasonic Sensors HC-SR04 is chosen as the main sensor to reduce cost. There has been experiment performed that shows that this form of sensor is capable to doing obstacle detection. (Source 2) Our project has also shown than it was able to avoid clearly defined obstacles easily. (Seen in the video as the robot avoids colliding the wall)

Cleaning Algorithm Design

The design of cleaning algorithm is as such: 

The initial idea is of S-walk algorithm, mapping and path finding. Rationale of S-walk algorithm is as above, being the “most’ efficient method that meet our needs. Mapping allows for the robot to identify its surroundings as well as recognise its location, prevent unnecessary trips. Path finding allows for the robot to find its starting point, allowing for the entire room to be covered, even if the robot does not start at the edge of the room. 

However, due to the complexity and time constraints, path finding was not implemented. Mapping was not fully implemented as well, with only the most basic structure formed. The robot is unable to simulate autonomous pathing, which could allow for customs maps to be used (Such as in the form of excel)

Many changes and features were added during this stage. 

CleanBot V3 is included for comparison

These are the following changes that we decided to make due to various problems and faults identified:

a) Platform at the back of the robot was removed.

Rationale: We decided to put the electronics either on the top of the robot or on the sides instead, where there were unutilized space. This allows us to further reduce the size of the robot despite the mistake of purchasing humongous stepper motors.

b) Added aluminum profile to the front of the structure.

Rationale: During motion testing, we realized that the top of the structure was vibrating violently due to the rotation of the stepper motors. Thereby, we had to add aluminum profiles to the front and tested the various positions to place the aluminum profile, without interfering with the swapping mechanism.

c) Added a bumper system to protect the wheels and the motors in the event of collision and failure of sensors to detect danger. 

Rationale: As this was highly recommended by both leading expert and founder of LionsBot, we decided to add this in to protect our wheels and motors

d) Removed the spring system which presses on the cloth on the floor and changed with a simpler system.

Rationale: Due to poor judgement and lack of experience, despite a plausible idea, we chose to buy wrong springs, which results in either the 3D structure continual snapping or the spring being deformed. This meant that the mechanism was not working as planned. Due to time constraints, we decided to fall back on a simple mechanism of the older idea: using a aluminum profile to press the cloth on the cloth. 

e) Added a primitive system to prevent the cloth from slipping as it was rolled. 

Rationale: As we were testing, we realised the cloth slipped as it was rolling. Drawing inspiration from toilet rollers/ cloth rollers in laboratories, we used an aluminium profile in an effort to replicate the design.

Figure: Showing the various stated mechanism added including c) Bumper system and e) system to prevent slipping of the cloth using aluminum profile.

The cleaning robot is designed to have 2 modules, the movement module and the cleaning module.

Putting them together

How it works (Cleaning Mechanism):

• Simplifying the idea of a “self-cleaning mechanism”, we decided to use a washable and reusable cloth. (Coconut Cloth)
• The water pipe will spray out water/cleaning solution onto the floor. The cloth would then wipe up the dirt and grime on the surface of the floor. 
• After a set interval of time, the clean cloth roll (left) will dispense out clean cloth while the dirty cloth will be rolled up on to the dirty cloth roll (right). This ensures that a clean cloth will be used to wipe up the dirt at any point in time. 
• The cloth is then detachable and able to be washed using a washing machine. It is washable and reusable up to 100 times. 

How it works (Swapping Mechanism):

• Sliding wheels on the sliding mechanism together with the caster wheels allow the the cleaning module to slide in with the movement module. 
• A pin and hole will act as the locking mechanism to hold the cleaning module in place, allowing for both the cleaning module and movement module to move together. 
• With this swapping mechanism, new cleaning modules can be created within the constraints and be attached to the movement frames for different purposes (Eg: Vacuum, Scrubbing, Floor Polishing etc)

CleanBot V2 (Iteration 1)

Idea:

• As an attempt to design a more specialized cleaning process, we stumble on to a new product Narwal Cleaning Robot (Narwal T10, 2-in-1 Robot Mop & Vacuum With Automatic Mop Cleaning Stat – Narwal Robotics)
• Narwal prides themselves as being the first self-cleaning cleaning robot, which cleans the brushes that are used to mop the floor. This removes the trouble of having to clean the dirty brushes, solving an issue that is prevalent in the market. 
• Building on that, we wanted to create a self-cleaning mechanism that allows for the washing of the cleaning material to be on the go, instead of being purely at the docking station. This allows for application to larger areas like factories, where the docking station could be very far away. 

What it was:

• CleanBot Version 2 develops on this idea by building on CleanBot Version 1. Instead of purely a stationary cloth at the back, we came up with a self-cleaning mechanism that allows the cloth to be continuously washed and reused while on the robot is on the go.

How it works:

• The nozzle will spray water/cleaning solution out onto the floor. The front scrub, which will be turned by a brushless motor, will speed at a speed faster than the wheels, allowing it to scrub the grim off the floor. A cloth that is attached at the back of the robot will be wipe up the grime and dirt that was scrubbed off the floor.
• The cloth will be rotated at fixed intervals and enter the tank of water to be scrubbed by the brush in the water tank. After which, it will be squeezed dry using 2 rollers and is then reused.

Why we changed it:

• As there was only one water tank, we foresee that the water would get dirty very quickly. After a while, we would be cleaning the dirty floor with dirty cloth soaked in dirty water. Therefore, we decided to revamp our idea in CleanBot Version 2 (Iteration 2)

CleanBot V2 (Iteration 2)

The modification:

We changed the water tank to be a dirty water tank instead. Clean water will spray on the cloth, washing it , while the dirty water after washing will be collected in the dirty water tank instead. This ensures that the cloth will be washed with clean water instead of being soaked in dirty water after a period of usage.

Why we changed it:

After feedback from Dr Ho and Mr Tony, we realized that the cleaning mechanism itself can be a project on its own. The complexity of the project, as well as the lack of time made us reconsider our idea. Mr Tony recommends us to separate the cleaning robot into 2 modules: the movement frame and the cleaning frame. This would allow us to start purchasing, as well as start building, rather than taking a large amount of time to plan out everything properly before building.

What it was:

CleanBot Version 1 was though to be a two-wheel driven robot, with a front caster wheel. This is designed to be made for scrubbing dirty floors and cleaning up the grime and dirt.

How it works:

The nozzle will spray water/cleaning solution out onto the floor. The front scrub, which will be turned by a brushless motor, will speed at a speed faster than the wheels, allowing it to scrub the grim off the floor. A cloth that is attached at the back of the robot will be wipe up the grime and dirt that was scrubbed off the floor.

Why we changed it:

After discussion with Dr Ho and Mr Tony, the cleaning process was deemed to be too simplified. Mr Tony also urged us to reconsider the cleaning process.

FetchBot

What it was:

Our initial idea was FetchBot, a robot that would be able to retrieve boxes of items from shelfs. 

We initially intended for this to be used in homes of the elderly to enable them to obtain items from another room without walking. We also believe that this could potentially be used in hospitals and nursing homes, where medication or food can be delivered to the elderly, reducing the interaction of the nurses and the elderly, especially in this Covid-19 pandemic situation.

How it works:

FetchBot was thought to be able to move in the Z axis (Up and down), as well as extend its “arms”(Linear Actuators) to carry trays of objects to and fro. 

It was initially designed to be an autonomous robot with mapping software, as well as manual control to allow the user to control the robot if necessary. 

Why we changed it:

After discussion with the Dr Ho and Mr Tony, we realised that our project was too complicated for a 3 month project, and it was very similar to another group’s project. Therefore, after some deliberation, we decided to change to a cleaning robot instead. Hence, the birth of CleanBot.