5 - Robot Navigation

Unit 5 - Robot Navigation

How do mobile robots navigate the physical world?

What Am I Learning and Why Learn This Now?

You've made robots that move, but did they have a destination in mind? Did they ever "trip" or run into something? Did you always clear their path first? The "real world" is messy -- stuff gets in the way! How do we make robots that can deal with obstacles? How do we program robots to go to specific places? Time to pull together everything you've learned so far about programming, gearing, and motion!

When you have completed this unit, you will have "met" competency 6 - Robot Navigation. You will also have your final summative grade on C1 - Engineering Process.

Am I Ready to Learn This?

Before attempting this unit, you should have demonstrated mastery of Competency 2 - Intro Programming and Competency 3 - Gearing. This unit assumes you already know how to work with the Legos and gears, and that you already know how to program your robot to sense and respond to its environment.

Typically, this is a longer unit for people, and it is the last unit of the scheduled semester course. You will need to manage your time to complete the course on pace.

Example Robotics Learning Project: Hospital Services Bot

Construct a robot that can deliver medication to patients in a hospital, nursing home, or similar facility. The robot needs to be able to avoid people, carts, and other irregularly shaped equipment that might be in its path. There is a dark line embedded in the white floor tile that marks the path from one room to the next, however, there are occasional dark tiles or other dark spots on the floor also.

We will "shrink" the scale of the obstacles and line to fit the scale of the LEGO robots. The teacher will identify the obstacles and randomly place them in the "hospital" on the day of the assessment. The "line" will be black electrical tape. The open space floor plan will be laid out and tape placed on the day of the assessment. There will be NO opportunity to "test" the robot in the final floor plan before the assessment.

The robot must have a max height of 60 cm, including any upward motion of the bot as it travels, and max width of 15 cm, including any side-to-side motion of the bot as it travels. The compartment space for the "medication" must be able to hold a plastic medicine cup with liquid water and four 4x4 Lego block "pills." The cup of water must be at least half full when it reaches the "patient" and the compartment space opens. The space must be closed during travel so that random passersby cannot take the medicine. (Yes, we realize that a human could just take the Legos apart or force open a Lego "door..." willing suspension of disbelief here please....)

The robot has to "deliver" the medication from the nurses's station to the right "patient." The teacher or other neutral party will assume the role of the nurse. The "patient" is a SECOND robot that you program, but that does not move at all. (Yes, you will probably have to share with a peer on the day of the assessment.) The teacher or other neutral third party will place the "patient" in a random place within the "hospital" floor, immediately next to the electrical tape line. NO STAIRS or elevators are involved.

Before the robot leaves the "nurse's station," the nurse must have a way to tell the robot which patient to deliver the medication to, as identified by a patient number between 1 and 4 chosen by the nurse. The nurse must also have a way to put the "medicine" in the delivery bot and tell it to go deliver it. (You, as the programmer of the "patient" bot, have a chance to tell the patient bot which number it is as soon as the nurse starts the delivery bot.) When the delivery bot reaches the "patient," the "patient" must communicate with the delivery robot to tell the robot to open it's container.

From the moment before the nurse identifies the patient number to the moment after the delivery bot opens its compartment to deliver the medication to the patient, you may not have any contact or communication with the delivery bot. After the successful delivery to the first patient, you can pick up your robot to manually move it back to the nurse's station. The delivery bot must successfully make TWO out of THREE deliveries.

Minimum Expectations for this project to be assessed:

• • Mechanism meets all the requirements of the task on assessment day

  • Journal shows evidence of testing at least two different algorithms for following a path

  • Journal shows evidence of testing at least three different algorithms for avoiding obstacles, using at least two different sensor types.

  • Journal shows evidence of at least four tests of individual parts of the system

  • Journal shows evidence of at least one "dress rehearsal" of the whole system

How to Navigate this Unit:

1. KNOW YOUR GOAL: READ the competency 6 rubric. Ask clarifying questions as needed. Some of the terms may be unfamiliar to you at the start of the unit.

2. PLAN: Define the task for the learning project described above. Break the task down into smaller systems for your parts analysis. Define "smaller" tasks for each part of the system. Begin some initial brainstorming for each part.

3. FORMAL PROGRESS CHECK: Schedule a formal check with your teacher. Discuss how you've broken down the bigger task, and what prior knowledge you bring to each part. Work with your teacher to plan how you will work through the smaller tasks to build up to the full project, including some preliminary deadlines and informal progress check points.

4. LEARN: Work through each of your smaller tasks, in an order that makes sense for you. CHECK-IN with your teacher as you work! Be sure that you are documenting different approaches, with pros/cons and testing cycles. Some words you should understand as you work include algorithm & Bluetooth/Infrared.

5. FORMAL PROGRESS CHECK: When you are ready, schedule a formal check in with your teacher. Demonstrate and discuss the mechanisms you've built and pieces of code you've written. Your teacher will help you check your understanding against the competency 6 rubric. Your teacher may suggest/assign other learning tasks and additional formal check-ins to help you. If you are aiming for a '4,' be sure your teacher knows. If your teacher agrees that you are ready, schedule your summative performance of your bot.

6. SUMMATIVE EVALUATION: Your completed delivery & patient bots, combined with evidence of your learning from your journal, notebook & formal check-in, IS your summative for competency 6. You will also get a summative assessment on your engineering journal.