Overview

Problem Overview

          The goal of the project is to design, construct, and program an autonomous robot to compete in an event similar to traditional human sumo matches [1]. Within this event, two robots will strive to force the other out of the arena by pushing in order to win the round. Each round will be three minutes long and the match ends when a team wins two out of three rounds. The bases of each robot will be constructed using a starting Lego NXT robot kit and the programming will be created using a language of the group’s desire.

Design Constraints

Arena Constraints:
          The arena is a circle with a diameter of 77 cm made of wood laminate, with a 2.5 cm black border around the edge of the ring as shown in Figure 1. The interior of the ring will be surfaced with white, allowing distinction between the various aspects of the ring. 

Figure 1. Representation of the arena

Robot Constraints:
          The robot must be autonomous and may not be controlled after the start of each round until a point is given. The robot must also not exceed a weight of 1 kg, a length of 20 cm, or a width of 20 cm, but may be of any height. In addition, the robot may expand in size after a match begins, however, it must remain as a single robot. If any rules are violated throughout the competition, the robot is disqualified [1].

Pre-Existing Solutions

          The design constraints for Robot Sumo allow for a lot of freedom in design, but for the most part many of the pre-existing solutions are very similar. The common design strategy behind robots participating in sumo consists of a low, compact robot with one of many different possible combinations of sensors used to detect the other robot and the edge of the arena. In addition to these aspects, almost every design has a specific feature, such as a wedge or ram, which is created to move the opposing robot out of the arena. Some examples of pre-existing solutions are shown below in Figures 2-4.

Figure 2. Design utilizing a wedge

Figure 3. Design utilizing a ram

Figure 4. Design utilizing unique spinning wheel

Design Goal

          The goal for the project is to build and program a robot that is able to push other robots out of the arena. To accomplish this goal, the proposed design is based around speed instead of traction unlike many pre-existing designs. The reasoning behind this thought process is that the faster robot will be able to avoid the slower, heavy traction robot's attacks and in time will catch the heavy traction robot in a weak spot, such as a side or a tire, where it would be easier to push out. In addition, a ramp is used on the front of the robot in order to get under the opposing robot to make the job of pushing easier.

          The design utilizes multiple sensors, including one light sensor, one ultrasonic sensor and two touch sensors. The light sensor is placed near the middle of the robot facing the ground so that it can detect the black border of the arena. When the border is encountered, the robot moves away in order to avoid being pushed out. The ultrasonic sensor is placed above of the NXT Intelligent Brick facing the ramp side so that it can be used to find and track the opposing robot. The two touch sensors are used on the opposite side of the robot as the ramp where they are attached to each other by a long block that covers the entire width of the robot. When the block is hit, one of the touch sensors will be triggered allowing the robot to know it is in danger from the back allowing for it to run away before going back on the attack. This unique feature is not present on many, if any, pre-existing designs and it seems to be a valid option to avoid being pushed out from a weak spot.
          Programming the robot will be done using the Not eXactly C, or NXC, programming language instead of the NXT block programming. This language provides a wide range of options that are not necessarily available in NXT block programming and considering that the design is heavily dependent on smarts, instead of brute strength in the form of traction, these options could be very important to success in the competition.

Project Deliverables
Robot:

• Build a robot that is capable of moving quickly around the arena
• Design a ramp that is able to get under another robot
• Add weight to robot to make it harder to push out
• Place the light, ultrasonic and touch sensors in effective positions on the robot
• Light sensor can detect border
• Ultrasonic sensor can find and track the opposing robot
• Touch sensors respond when robot is hit in the back

Algorithm:

• Develop an algorithm that uses multiple offensive and defensive strategies

Project Schedule

Week 1:

• Form group and exchange information
• Create website
• Begin research

Week 2:

• Gain an understanding of the NXT kit
• Learn about NXC programming language
• Finish design proposal
• Blog post

Week 3:

• Construct robot based on design proposal
• Begin creating algorithm
• Blog post

Week 4:

• Complete algorithm
• Modify robot
• Blog post

Week 5:

• Preliminary testing and modification
• Research design possibilities
• Blog post

Week 6:

• Testing and modification
• Research design possibilities
• Blog post

Week 7:

• Testing and modification
• Research design possibilities
• Blog post

Week 8:

• Final testing and modification
• Blog post

Week 9:

• Competition
• Blog post

Week 10:

• Presentation

Projected Budget

• Lego NXT Kit (Provided by Drexel University) - $279.95
• Total Expected Cost* - $279.95

* Extra materials may be used in small quantities that would not affect the total cost