Final Contest Challenge





As part of this freshman design course, students (working in groups) will design, construct, and program a Lego RCX microprocessor-based robot. The robot has to pick up tennis balls positioned arbitrarily in a square arena and place them outside the arena, as fast as possible. 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 (with three geared motors and a rotation sensor).

·          Optional: additional touch sensors, light sensor, mercury switch, and bend sensors.


Each robot should carry a visible label (or a small flag) that identifies its creator team’s 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’ x 4’ surrounded by a 3” height black walls. No obstacles will be placed in the arena. The arena will contain several tennis balls. 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 banner (flag) that has the team number 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 tennis balls and place them outside the area (i.e., the tennis balls should end up laying on the floor.) There will be a maximum time of 2 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 that places all balls outside the arena in the shortest time. Here we take the best of the two runs. If no robot gets rid of all balls in the allotted time, the one that gets rid of most balls wins. If multiple robots get rid of the same number of balls, the winner is the one that takes the smallest total amount of time for its most successful run (counting only the time till the last ball is removed).



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.

·          The kits (including all additional lego parts, sensors, motors, connectors, etc.) must be SORTED and returned to the instructor in a very good shape and in perfect operating conditions.



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. The NQC code must not duplicate significant portions of code that currently exist in texts or on the web. Each group has to write a final project report and post its electronic version on the team’s web page. The report must describe 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). Total length about 10 pages.




As mentioned earlier, 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.


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


The final report is due by 5:00 pm (sharp!) the next day after the competition.