Exercises: Design and construction of robots

The image shows an educational wheeled robot with its parts numbered. Identify each part and explain what function it serves within the robot (structure, movement, control or perception).

Name the basic parts of a simple mobile robot and state which element of a control system (sensor, controller or actuator) each one corresponds to.

The flowchart in the figure shows the program for an obstacle-avoiding robot. Describe the complete behaviour of the robot in your own words and reason what it would do if the distance sensor were covered with insulating tape.

Name three real-world tasks currently carried out by robots (domestic cleaning, factory welding, warehouse delivery) and reason what sensors each one needs for its task.

Explain the difference between a robot and a simple automatic machine such as a washing machine: what capabilities make a system "deserve" to be called a robot?

What is a robot chassis and what qualities must it possess (lightweight, rigid, with space for electronics)? Relate this to materials you know from the workshop.

Explain what a servomotor is and how it differs from a standard DC motor. Give a suitable use for each one inside a robot.

Many two-wheel drive robots feature a third, unpowered caster wheel. Explain its purpose and what support and balance issue it solves.

Your robot must follow a black line painted on the white classroom floor. Reason what sensor it needs, where you would place it, and what the program should do every time the sensor strays from the line.

A robot has two drive wheels, one on each side. Explain what each wheel must do (spin forwards, backwards, or stop) for the robot to move forward in a straight line, reverse, and spin on the spot to the right.

Put these steps for building and programming a robot in order, and justify the sequence: upload the program to the board, assemble the chassis, test and calibrate, connect sensors and motors to the board, define what the robot should do.

Your robot must turn 90 degrees accurately using its two wheels. Explain why the command "turn for one second" is unreliable (battery level, surface, friction) and what additional information would improve the turn.

Design the weight distribution of a mobile robot: where would you place the battery (the heaviest component) and why does its position affect stability and drive-wheel traction?

A line-following robot skids and flies off course on sharp bends. Propose two improvements, one mechanical and one in the software, and explain how each one works.

Explain what sensor calibration is and write a short procedure to calibrate a robot's light sensor in your classroom (which two reference readings to take and how to use them).

An obstacle-avoiding robot must also avoid falling down a step or flight of stairs. What sensor would you add, where would you place it, and using what programming rule?

A robot moves forward in a straight line for only a few metres and then gradually veers to the left. Analyse at least three possible causes (mechanical, electrical, or software-related) and explain what test you would carry out to rule out each one.

Design a robot to distribute leaflets along the school corridors: describe the chassis, sensors, actuators and general movement algorithm, and justify each choice considering the real environment (people, junctions, obstacles).

A team is programming a line-follower robot with speed control and ultrasonic obstacle detection. In a block-based programming environment, they have nested conditionals with fixed pauses ("wait 50 ms"), which causes the robot to react late and veer off the track if it exceeds 0,2 m/s. Explain technically why typical block-based sequential programming causes this latency and processor blocking issue. Justify what technical advantages migrating the program to text-based code (such as C++/Arduino) using non-blocking timing (with millis()) or interrupts offers, and reason how the control structure changes to resolve the issue.

Design a robot to collect tennis balls from the school court: chassis, sensors, actuators, and general search and collection algorithm. Identify the three most critical design decisions and justify them.

A robot with a single front distance sensor gets "trapped" in corners, oscillating between two walls. Analyse why this behaviour occurs and propose an algorithm improvement (recording recent turns, introducing turns of different angles).

You must select the drive system for an inspection robot in a greenhouse with 60 cm wide aisles, zero-radius turns on its own axis, and damp soil with irrigation pipes protruding up to 3 cm. The robot has a fixed 12 V and 7 Ah battery and must guarantee 4 h of continuous runtime. Analyze the physical behavior of three options: 1) Two drive wheels with a caster wheel, 2) Fixed 4WD (skid-steering), and 3) Continuous tracks. Predict which critical failure rules out two of them (in terms of traction, maneuverability, or consumption due to lateral friction) and justify what the optimal configuration is to meet all constraints.

Design the "safe mode" for a school robot: what should the program do upon detecting low battery, a persistent obstacle, or loss of communication? Write the rules and reason why safety comes before the mission.

In a search and rescue trial in a collapsed environment, a robot must locate and shut off a gas valve. The team debates whether to use RF teleoperated control with a camera or 100% autonomous control with sensors. The environment presents two critical problems: blind spots with link losses of up to 1,5 s and unforeseen obstacles that require braking in less than 0,3 s while moving at 0,4 m/s. Predict the failures that the exclusively teleoperated robot will suffer in the face of these limitations and justify why a hybrid architecture (teleoperation assisted by local safety routines on the microcontroller) is technically superior to both options, detailing what decisions the robot must make on its own without waiting for the pilot.