Problem Overview
Robot Sumo is similar to the ancient Japanese Sumo wrestling, but instead of people, we use NXT robots. The goal is to create a robot that is able to push an opposing robot out of the ring. To do this, one has to know how to counteract the force done by the other robot, and have a sophisticated enough program that allows for an offensive and defensive strategy.
The true problem lies in the capabilities of the NXT software and its physical components. NXT is more or less a collection of toy pieces with few sophisticated sensors. This means that the robot can come apart relatively easy, if enough force is applied. Also the means that the robot is light, making it is easier to manipulate. With that, the NXT software has its limits; turning accuracy is almost none existent and programs might not always work, depending on the environment.
In all, the problem is being able to make a functioning robot that won’t easily break under pressure while being able to counter forces and the opponent’s strategies.
Design Constraints
The ring is a 77cm diameter circle of wood laminate, with a white border around the circumference of the ring. The interior of the ring is black except for 2 white starting lines. One match consists of 3 rounds, where the goal is to push the other robot out of the ring while remaining in the ring. The robot must also fit into set dimensions; 20cm by 20cm (no height limit)
These dimensions ensure that no one’s robot has an overbearing presence on the field.
These constraints impact the way the robot is designed. To compensate for the dimensions of the ring, the robot has to have a way of realizing where it is on the field. This could mean putting multiple color sensors facing the floor or using multiple ultrasonic sensors. However, the sensors can’t be placed outside of the dimension boundary so that requires sacrifice in one area or another. These constraints ultimately determine the design of the robot.
Pre-Existing Solutions
The goal of the project is to push the other Sumo robot out of the ring. In order to do that, the robot needs to be able to push out, obviously, and defend itself from getting pushed.
To push the other, the robot has to consist of enough power and momentum. To get the maximum rotational power from a motor, the group can increase the gear ratio. One rotation of the motor, for example, will result three rotations of the wheels. Also, to carry a good quantity of momentum, the robot could make big arch turns instead of stopping and making zero point turns.
Making an attacking mode robot is not the best idea because the other robot can counter attack by using the robot’s power and momentum. Therefore, the robot has to be ready for a counter attack. The robot needs to be able to sense the edge of the ring. When it is near the edge, the robot has to make a 180 degree turn and explode to the other side of the edge. The basic of the defensive robot is about the center of its body weight; the center of the body weight has to be as low as possible, so that the robot would not tip over.
One other problem that is easily found during competitions is that remote control is not able to control the robot when there are obstacles on the way. However, the group won’t have this problem because the code will be manually downloaded and played as the competition starts. A good algorithm is the key of winning.
Design Goals
The goal for this project is simple; to design and create a robot that will be able to push another robot out of the ring. In order to do that, the robot has to be able to counter the forces that are applied to it while maintaining it momentum in the desired direction. The best way to do this was to use a gear ratio that allowed for a greater amount of torque than was made by just the motors moving. Figure 1 show the gear ratio used for the robot.
As seen in this figure, the gear that is attached to the motor is smaller than the gear it interconnects with. The next two gears continue with that form of ratio further increasing torque output. Because of this ratio, the robot itself moves extremely slowly when compared to the amount of revolution the motor is doing. However, for this competition, speed does not matter as much as forward force which is why this ratio is applicable.
In addition to the gear ratio, there is the angled ram in the front of the robot. Figure 2 shows the angled ram.
The ram’s purpose is to uproot the other robot on the field so that they lose traction, making it easy for our robot to push them out of the ring. Basically, as we move forward, the angle of the ram will provide lifting force that will slant or tip the other robot. To prevent the other robot from hitting the components, this rams also has a barrier which serves as protection to the internal components and prevents them from being harmed. The ram will ensure that our robot last the match while providing additional support.
Other design plans are the two back swivel wheels and the ultrasonic sensor. The two rear wheels allow for more dynamic and fluid movement. Have these two, instead of only one, also allows for increase stability and tipping prevention; distributing the weight. The ultrasonic sensor is placed, at a slight downward angle, so that it sees over the protective barrier and is able to find its target. Having the sensor mounted this high, insures that it won’t be compromised by competing bots.
Individually, all of these designs have been seen in other competing robots in the past. However the combination of them is what makes this robot unique. Having the torque and the ram with increase movement capability and component protection will allow this robot to successfully perform the task that is required by the game.
Project Deliverables
Create a robot that is able to perform the task
·Able to maintain momentum against an opposing robot
· ·Able to locate another robot
· ·Able to move dynamically
· ·Increase the weight of the robot
Create a working program:
· ·Able to find opponent
· ·Able to seek opponent
· ·Able to avoid being pushed out
· ·Does not confuse opponent and environment
Extra deliverables:
· ·Have robot move Chemistry and Calculus textbooks (separate and stacked)
· ·Robot is capable of lifting another robot
Project Schedule
Week
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Date
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Lab
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Group Meetings and Discussions(weekends after lab)
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Assignments(due)
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Select a project
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1
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4/4/2012
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Get a group of four or five Share each other’s contact information
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Initiate the blog
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2
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4/11/2012
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Rent out two NXT kits
Design the robot
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Update the blog
Work on the proposal and submit
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Setting up a blog
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3
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4/18/2012
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Learn how to work with NXT software
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Design the robot
Keep the updates
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Design Proposal Deliverable
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4
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4/25/2012
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Create a code
Test out the robot and the code
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Discuss, analyze, and solve problems
Re-design the robot
Keep the updates
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5
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5/2/2012
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Build a ring of our own
Simulate the robot with the code
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Check over the blog
Make changes if needed
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6
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5/9/2012
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Online research the project
(previous competition, videos, etc)
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Discuss, analyze, and solve problems
Re-design the robot
Keep the updates
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Website and Progress I
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7
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5/16/2012
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Work on the code
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Discuss, analyze, and solve problems
Final check-up for robot and algorithms
Keep the updates
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8
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5/23/2012
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Evaluate problems
Finalize the design
Test out the robot
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Check over the blog
Make changes if needed
Prepare for the competition
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9
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5/30/2012
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COMPETITION
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Create a PowerPoint
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Website and Progress II
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10
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6/6/2012
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PRESENTATION
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Presentation
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Project Budget
For the project, Sumo Robot, the group will need a small amount of money in order to upgrade the robot and afford the settings. The main part of the robot will be made out of the NXT kits that the group rented from Drexel University.
This “Project Budget” will show both the cost of the project and sources of support that the group will access to pay for the project.
INCOME
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INCOME SOURCE
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AMOUNT
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Fundraising Events
(brownies & cookies)
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$150
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Contributions from individuals
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$50
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Contributions from Drexel University
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$0
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TOTAL PROJECT INCOME
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$200
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EXPENSE
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TYPE OF EXPENSE
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COST
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For fundraising
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$50
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For the ring set-up
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$25
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Meeting Materials
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$25
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Update Materials for Robot
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$100
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TOTAL PROJECT EXPENSE
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$200
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