Final Contest Challenge

Winter 2005

 

 

Introduction

 

As part of this freshman design course, students (working in groups of three) will design, construct, and program a Lego RCX microprocessor-based robot. The robot has to pick up practice golf balls (light weight plastic balls) positioned arbitrarily in a square arena. The robot must store the balls in an onboard bin (once stored, the balls may not touch the floor of the arena). The arena will contain up to 20 Table Tennis balls (red, yellow, green and silver). The balls are positioned in a predefined but undisclosed location inside the arena.Every successfully collected silver ball earns your team one point. For each collected non-silver ball the team loses Ĺ point. There will be a maximum time of 3 minutes for the robot to complete the task. Each team will have two chances at the challenge. The score of the best run will be counted. The goal of the project is that students will get an insight into the problems involving:

 

             Robust robot design and building (design subject to constraints)

             Autonomous navigation (automatic exploration)

             Programming in NQC (NQC is a C-like language for the RCX)

             Sensing and locomotion

             Dealing with imprecision and real environments

             Developing team-work skills

 

 

Construction Materials

Each team gets the following material:

 

             One Lego Mindstorms Robotic Invention Set.

             One additional motor (geared, non-geared, or micro)

             One infra red (IR) or sonar sensor

             One rotation sensor

             Optional: additional sensors and Lego pieces may be used upon the approval of the instructor.

 

Each robot should carry a visible label (or a small flag) that identifies its creator teamís number

 

Programming Environment

The teams are expected to program their robot using NQC. The robots should run in stand-alone mode (i.e., autonomously). That means that a program for the task must be downloaded to the robot (in program slot 1) after which the robot is started (using the remote control). There can be no interaction between the robot and a computer or remote control while performing the tasks.

 

The Challenge

The arena will be a square (painted black) of approximately 4 ft x 4 ft surrounded by a 3 inch height black walls. No obstacles will be placed in the arena. The arena will contain up to 20 Table Tennis balls (red, yellow, green and silver). The balls are positioned in a predefined but undisclosed location inside the arena.

 

The robot starts at the center of the arena, with its front pointing to a predefined direction. The robot runs will be video taped. Each robot should carry a small flag that has the team number and name on it (printed in sufficiently large font size so that the video may identify the robot with its creator team.)

 

The robot has to find the silver balls and load them into an onboard storage bin. Every successfully collected silver ball earns your team one point. For each collected non-silver ball the team loses Ĺ point. There will be a maximum time of 3 minutes for the robot to complete the task.

 

Next, the balls are placed back inside the arena, and the robot gets a second chance to solve the problem; starting at the center of the arena, but pointing in the opposite direction relative to the first run.

 

The winner is the robot with the highest score. Here we take the best of the two runs.

 

Additional Rules

The following additional rules apply:

 

             The robots are to stay confined inside the arena at all times.

             The robots must work autonomous using a downloaded NQC program in program slot 1. No outside intervention is allowed, except for the initial activation of the robot using the remote control device.

             In all cases, the referee team (made up of the instructor and TAs) decide and their decision is binding.

             The kits (including all additional Lego parts, sensors, motors, connectors, etc.) must be returned to the instructor in a very good shape and in perfect operating conditions immediately after the competition. The TA will verify the condition of the kit for each team.

 

 

Final Result

Although winning the challenge is, of course, nice, the project will be judged on other criteria. Robot originality, simplicity of design, and minimal use of Lego parts and sensors are desirable features. Each group has to write a report (and post its electronically on the teamís web page) describing the global solution strategy chosen (with a motivation why this is the best strategy), the design of the robot (with a motivation of the design choices), and the NQC program (together with an explanation of how it works and how particular problems have been dealt with). Each team should post their report (and any additional material relating to the final project) on the teamís web page. The final report is due by 5:00 pm (sharp!) the next day after the competition.

 

 

Logistics

As mentioned above, each team will get one Lego Mindstorms set and few additional Lego components. The team is responsible for returning the complete set immediately after the competition. The team is responsible for replacement batteries.

 

The team is expected to perform the construction and programming on campus, in the lab and/or off campus.

 

One test session will be organized one week before the challenge in which the teams can test whether their programs work in the actual arena.

 

The final competition will take place during the scheduled final exam week or as announced in advance.