Example Proposal in the Sciences

Example Proposal in the Sciences

Robo-Hockey

Kelly Minion

Electrical Engineering 4951

Department of Electrical Engineering

University of Minnesota

Minneapolis, Minnesota 55455

Professor Phil Cohen

15 January 2005

Robo-Hockey

Abstract

Senior Design Group 4B has planned to design and build a working prototype that will enable an individual human to play a game of air hockey against a robotic opponent that will block the human's shots 90% of the time. Amusement centers such as bars and bowling centers seek a variety of ways to keep their patrons entertained while also producing secondary revenue streams. Pinball machines and games such as PacMan and Pong are quickly becoming outdated, and therefore generate less revenue. Our project proposal strives to capitalize on this opportunity by combining the advantages of optics and robotics to build an affordable and exciting new form of entertainment we call “Robo-hockey”. Our design consists of integrating a playing surface, puck, optics, a control unit, and a paddle.

Introduction

Air-hockey is an entertaining game that has been played for many years by people of all ages. The popularity of this game still exists today for amusement and competition purposes in entertainment venues around the world. A typical game of air-hockey requires there to be a minimum of two players. Each must be on an opposing team, without any alternatives for individual play. The current proposal will address this problem by allowing an individual player to practice playing against a mechanical opponent.

The main purpose of this project is to design and build a robot that will defend one end of the hockey table, and also have the capability to return the puck without much emphasis on the ability to score goals. The robot will be interfaced and controlled with a computer and have the ability to block at least 90% of an average player's shots. Before now, video games were the only option for a lone individual to challenge an opponent with artificial intelligence. This new robo-hockey game will allow individuals to play in a lively and realistic gaming experience.

Project Plan

Our team has researched and devised a plan to create the robo-hockey prototype. This prototype will consist of a playing surface, puck, optics, a control unit, and a striker. As shown in Figure 1-1, the optics will sit over the playing surface and interface with a controller. The controller will interpret and analyze the image data received from the optics, and send signals to move the striker.

Figure 1-1

Surface:

The playing surface will be very basic: a piece of plywood with two 2 x 4 planks on the sides to act as walls and enclose the play area. The absence of back walls on the playing surface will serve as the goal areas. The playing surface will be made smooth to recreate the air-hockey experience by sanding the playing surface or covering it with a veneer, lacquer, Mylar, or Plexiglas. The finished playing surface will be set on top of a table so it will be at a height that will be comfortable for a human player during play.

Puck:

The puck will be very similar to an official NHL puck: 3 inches in diameter and with a thickness of 1 inch. The weight of a real hockey puck is about 6 ounces, which will be much too heavy, so we will be using a lighter puck such as a puck designed for street hockey. These pucks are designed for non-smooth surfaces and should be sufficient for our needs. Because friction on the table may be a factor, we may have to use a puck that has ball-shaped wheels on its bottom. We will test both pucks and determine which puck offers a better range of motion.

Optics:

The optics system will sit above the table and be positioned in such a manner that will give the best range of view. For optics, we are going to use a Web Cam that will be linked to a computer through the USB port. For optimal success in detection of the puck

by the camera, we will need to have the board and puck painted with contrasting colors. The table will probably be white and the puck will probably be black.

Control:

The controller for the system will consist of a computer that will operate the software and will be linked to the camera. We are in the process of researching the programs LabView, OpenCV, and DirectX. We will determine which program will be most efficient and suit our needs. We are leaning more towards the program OpenCv. Another option that will be considered is the use of a micro-controller that will help communicate between the computer and the motor if needed. The computer will take images from the camera and then interpret the location and direction of travel for the puck. Signals will be sent to the stepper motor to move the paddle into its defensive position.

Paddle:

The paddle is the mechanical part of the system that will block and return incoming shots. It will contain a solenoid attached to a 3” long face that will propel the puck forward. A micro-switch will detect the incoming puck and activate the solenoid to shoot the puck. The paddle will be constructed out of a hard plastic to ensure strength and long-lasting stability. The area behind this face of the paddle will be used for housing the solenoid and wires.

We anticipate the need for a strong reinforcement for the paddle. This will be accomplished by designing a support system above and below the paddle. The paddle

will be hung from six metal wheels. These wheels will have a grooved channel around the outside diameter that will run along two metal rods from above. This design will help carry the paddle as it moves along the goal area. Underneath the carriage of the paddle, several balls will help bear the weight created by the force of gravity.

Paddle Movement:

A stepper motor will provide the power needed for the movement of the paddle along the goal area. The stepper motor will be used to drive a gear system to position the striker to block the incoming puck. The stepper motor control will come from the computer as a series of signal pulses. The duration and the number of pulses will determine the amount of movement for the stepper motor.

The biggest challenge that we anticipate will be the interface between computer and paddle. For the project to be successful, we need the paddle to move to an exact position in order to block the incoming shots. The computer will need to communicate with the stepper motor for this to happen correctly. We will create an interface to these two systems early to allow sufficient time for troubleshooting and testing.

Construction:

The overall construction will be sturdy. All of the equipment will be tested so that it can withstand repetitive hits by a puck. Another major construction point will be in the paddle’s overhead movement system. Two rods will be used to eliminate any sway caused by the force of a sharply hit puck. The weight of the support system will also be

considered. A support system that is too heavy may create more drag, sacrificing the swiftness of the paddle movement. The cables used should be durable enough to withstand vibrations and movement but should not add to the overall drag of the system. In addition, fuses will be used in electrical systems to protect against power surges. Numerous tests will be done to ensure high speed, high durability, and soundness of the electrical system.

Team Planning:

To accomplish our tasks, project participants will be divided into two teams. The first will be the “Electrical and Mechanical Team,” which will be responsible for designing the power supplies and electrical systems. They will build the surface and the paddle. They will set-up the stepper motor to control the paddles movements. Additionally, this team will mount everything into place. The second team will be the "Software Team," responsible for developing the needed software and creating an interface between the camera and the computer. A project leader will work with both teams.

Project Schedule:

Table 1-1 provides a brief overview for the project plan.

Date / Mech and Elec Team / Software Teams
By Oct 1st / Parts Ordered / Camera ordered and finalize software decision
By Nov 1st / Finish Team Effort / Finished Team Effort
By Dec 1st / Link up with Software and Testing / Link up with Mech/EE and Testing
By Dec 6th / Demonstrate / Demonstrate

Table 1-1

Team meetings will take place on a weekly basis to ensure that the project is going as planned, and to discuss any problems that might have come about.

Budget:

Table 1-2 is an estimated budget of parts we anticipate using for the design of the Robo-hockey prototype.

Proposed Budget
Item / Quantity / Cost / Total
Board / Plywood / 1 / $20.00 / $20.00
2”x4” / 2 / $2.50 / $5.00
Misc / 1 / $25.00 / $25.00
Optics / Camera / 1 / $50.00 / $50.00
Misc / 1 / $15.00 / $15.00
Movement / Solenoid / 1 / $30.00 / $30.00
Motor / 1 / $40.00 / $40.00
Materials / 1 / $20.00 / $20.00
Belt/Gears / 1 / $10.00 / $10.00
Misc / 1 / $10.00 / $10.00
Misc / 1 / $25.00 / $25.00
Total / $250.00

Table 1-2

Summary

The main goal of this project is to design and create a working robo-hockey prototype. This robo-hockey prototype will consist of a playing surface, puck, optics, a control unit, and paddle. The prototype will be able to defend and block an opponent's shot and it also needs to be durable and not break down. We believe that the design and construction of

the robo-hockey prototype is a feasible project that can be done successfully with a budget under $250 (U.S. dollars).