Lab 4

Faculty Notes

The Robot Race

Background

Basic skills in mathematics, curiosity, interest in how components work together, and perseverance are all needed to be successful with this robotics lab/contest.

Implementing

The technology problem includes several workplace competencies. A key component is the importance of working and relying on your team members for support and ideas. Students will find the need to collaborate consistently. Additionally, the lab will involve a great deal of trial and error. From our experience this is not an easy aspect for anyone to deal with. A positive and supportive atmosphere will be a needed ingredient for effectively working together on the lab. One of the reasons to have students initially construct a robot using the step-by-step instructions with the kit is to have students begin with a positive and successful learning experience. Instructions are available on the CD and in Constructopedia. Time for students to play and become familiar with the materials in the kit needs to be included as you begin the lab. An excellent resource for both the student and teacher is: http://mindstorms.lego.com. This site contains building and programming tips, projects that others have created, and a link so that you can even post your own design.

Another aspect that makes this lab unique is the blend of math, electronics, engineering and programming in conjunction with the scientific method. Students are traditionally taught these concepts in isolation. This integrated approach will make these subjects come alive. As they progress through designing and testing, it may be helpful to plan mini-sessions for sharing to take place in a large group. Once they get to the contest, they may be restricted to sharing with only their team members because of the competitive nature of the lab.

For the initial research portion of the lab, the students should use both the web and textbooks. Besides the "How Stuff Works" web site, http://www.efunda.com and http://www.cpo.com are good resources for information about gears and pulleys.

To aid the students in their analysis of gears and gear ratios, ask them to experiment with different gear ratios on their first robot. They should record the time required for the robot to traverse a one-meter distance for each different gear ratio. They should then create a scatterplot, describe the function, and use a graphing calculator to get a best-fit function.

The next step in the technology problem is for students to reverse the direction of the robot when it hits an object. Students will find it necessary to research this component of the problem on the web. Remind students that they have only 2 sensors available, touch and light sensors. The Mindstorms web site is full of information that students can access to give them some ideas on how to attempt to solve this problem. Many practical hints are available on the web site, such as those dealing with the basic components in electronics.

From the onset of the lab, students will need to decide on what information will be included in their model portfolio. The benefit of keeping notes as they learn new terminology should be stressed. It will be important for students to carefully record their findings in both instances of success and failure. When students make a change in their design, it is essential that they note what the robot can do, as well as what the robot cannot do.

The final phase of the lab will be the most challenging – to design and build a robot that will transverse a course in the shortest time while remaining intact in order to win the contest. Students need access to the actual course to practice and strategize. The students should determine the rules of the contest by describing what actions will gain points and what actions will lose points. Teams will need to consider time, speed, accuracy, and the role of sensors to decide how they will progress with the contest.

To create the robot, students will need to understand or determine the following:

• the ratios of the lengths and heights of the different bricks, plates, and beams
• how to use ratios and proportions to decide which gears to use and whether to gear up or gear down
• how the knobs fit and how to strengthen the robot construction so it does not fall apart (this involves finding Pythagorean triples to build strong triangular structures)
• loops and conditionals in programming
• how the light sensor and touch sensor work and how to use them

Materials

This lab will use the LEGO® MINDSTORMS Robotics Invention System (RIS) 1.5. It includes over 700 LEGO® pieces and an RCX (a programmable brick). Students will need access to computers with internet capabilities to program the RCX and also to do research. The cost of the kit is approximately $199. A lab fee may be a consideration. One kit could be used by up to 3 teams, so a lab fee of $70 per team would cover the cost. The kits can also be reused by disassembling the robots after the lab is completed. Additional pieces and parts may be purchased, increasing the number of teams that could use one kit without a large increase in cost. A local industry might support the lab by purchasing several kits.

If you have access to other robotic materials, feel free to use them.

Enriching/Extending

• Students may be interested in becoming a part of a network of LEGO® users. They can network through the web site: http://www.news.lugnet.com/
• Initially students should research the history of robotics. Throughout the lab students should research the role of robotics in manufacturing and industry, traffic control, medicine, science and virtual manufacturing.
• Students can build and design a kinetic structure (an artistic sculpture that includes motion). This requires a much more complicated design but would also link to the subject of art. As an example, creating a bubble machine would result in a sense of accomplishment and also include an element of enjoyment.
• Students can be asked to research and write a reaction paper regarding social issues. For example, as robots take over jobs in manufacturing, how are people affected. Another possible topic might be the impact of artificial intelligence on our lives.
• Students interested in building a robot from odds and ends may log on to:
  http://www.build-it-yourself.com

Figure 1 that follows shows a possible course (from LEGO®). The students must choose between using the light sensor to traverse the black path or using the touch sensor to go over the bridge in the center.

You may choose to design your own course, or have the class decide on a course.