From the course catalog: Experiential seminar provides an introduction to the fundamental aspects of robust autonomous machines that includes an overall systems/component-level overview. Projects involve hands-on investigations with a variety of sensors and completely functioning, small-scale autonomous machines utilized for in-class implementation/testing of control algorithms. Uses Arduino.

Outline

(Generated by ChatGPT)

1. Basics of Arduino and Breadboards

• Sensors: Output either analog (continuous) or discrete (HIGH/LOW) data.
• Arduino Basics:
  • Key functions: setup(), loop(), pinMode(), digitalRead(), digitalWrite(), delay(), millis().
  • Inputs and outputs: Use INPUT_PULLUP to reverse signal logic (0 = HIGH, 1 = LOW).
• Breadboard Overview:
  • Red (+) columns = 5 V, black (-) columns = ground.
  • Split rows for circuit connections.

2. Limit Switches, Serial Communication, and Randomization

• Limit Switches: Use INPUT_PULLUP for toggling HIGH/LOW states.
• Serial Communication:
  • Functions: Serial.begin(speed), Serial.print(), and Serial.println().
  • Float precision formatting: Serial.print(x, 2).
• Random Numbers:
  • random(a, b) generates integers in [a, b-1].
  • Seed with randomSeed(x) for varied outputs.

3. Analog Sensors and Interpolation

• Analog Inputs:
  • Pins A0-A5 for reading sensor voltages.
  • Function: analogRead(pin) returns values (0–1023).
• Sensors:
  • Photoresistor: Resistance decreases with increased light.
  • Force Sensor: Resistance changes based on applied force.
• Data Interpretation: Use plots and interpolation (e.g., linear) for translating sensor outputs to meaningful values.

4. Career Lecture

• Resume Writing:
  • Highlight interpersonal, conceptual, and technical skills.
  • Use PAR (Problem, Action, Result) statements for experiences.
  • Coursework and class projects can be included as experiences.
  • Customize the resume with keywords from the job description.
• Cover Letters:
  • Personalize using common connections or events you attended.
  • Write a draft yourself before refining with tools like ChatGPT.
• Career Fair Prep:
  • Define goals: industries of interest, skills to showcase.
  • Research companies and prepare an elevator pitch with questions.
• Cold Emailing:
  • Send a pitch and follow up after 2 weeks if no response.

5. Servo Motors and State Machines

• Servo Motors:
  • Rotate within 180° or continuously, using three wires (VCC, ground, signal).
  • Controlled via the Arduino Servo library (disables analog pins 9/10).
  • Key functions: servo.attach(pin) and servo.write(position).
• State Machines:
  • Framework for programming actions based on specific sensor states or values.

6. Sensor and Motor Shields

• Sensor Shield:
  • Simplifies connections for sensors, servos, and modules to the Arduino.
• Custom DC Motor Shield:
  • Used to control front wheels of cars.
  • Utilizes pulse-width modulation (PWM) to adjust analog signals via digital outputs.

9. Line Tracking Sensors (nice)

• Line Tracking Sensor:
  • Uses an infrared emitter and receiver to differentiate light and dark.
  • Analog output: 0 (black) to 1000 (white); optimal sensor distance is 1–5 cm.
• Calibration Process:
  • Place each of the 5 sensors over the black track and record readings.
  • Determine min/max values for each sensor, normalize, and constrain readings to [0, 1].
• Line Tracking Method:
  • Black readings = mass of weight 1; white readings = mass of weight 0.
  • Use the center of gravity of these masses to estimate line location.

10. Bang-Bang Controller and Motor Behavior

• Bang-Bang Controller:
  • Simplest controller type (e.g., a heater): toggles on/off based on a setpoint.
• Motor Observations:
  • Programmed motor speeds may yield varying RPMs due to external factors.
• Line Tracking Failures:
  • Ensure I_tot (intensity total) is not zero; add a small bias to prevent loss of signal.

12. Bang-Bang vs. PID Controllers

• Bang-Bang Line Tracking:
  • Oscillates around a setpoint, requiring significant trial and error.
• PID Controller:
  • Uses error between setpoint and sensor value to adjust left and right turn speeds automatically.
  • Separate PID controllers for each wheel (e.g., KP_left, KP_right).
  • Derivative term can cause “jerky” behavior if tuned incorrectly; it may not always be necessary.

13. PID Controller Calibration

• Calibration Steps:
  1. Set integral and derivative gains to zero, then adjust proportional gain to match Bang-Bang behavior.
  2. Add derivative gain to prevent overshooting the line.
  3. Add integral gain to prevent slow off-center movement.
• Debugging: Adjust the setpoint for testing; the controller should work regardless of the setpoint.

16. Inertial Measurement Unit (IMU)

• IMU Overview:
  • Measures roll, pitch, yaw, rotation velocity, and acceleration.
  • Uses the Adafruit sensor library for data reading.
• Angle Outputs:
  • Default sensor outputs are in an unconventional orientation.
  • Remap values using the atan2 function to standardize them to the range [-π, π].

19. Interrupt Service Routines and Encoders

• Interrupt Service Routines (ISR):
  • Short code segments triggered by interrupts, executed alongside the main program.
• Incremental Encoders:
  • Count state changes (HIGH/LOW) for rotation tracking.
  • Quadrature Method: Uses two offset sensors detecting magnetic fields in a square wave pattern to determine rotation direction (CW/CCW) and velocity.

20. Physics and Non-Blocking Code

• Physics Calculations:
  • Distance derived as a function of echo time.
• Blocking vs. Non-Blocking Code:
  • Prefer non-blocking code for smoother operation.

22. Maze

• Maze Setup:
  • Entrance at one of the 4 bottom squares, starting just outside the maze.
  • Exit at one of the 4 top squares, potentially with a small entrance ramp.
    • I combined the A* pathfinding algorithm with an ultrasonic sensor to rock this challenge!

23. Mechanics and Materials Review

• Torque and Moments:
  • Definition: Torque is equivalent to a moment (or couple) in Mechanical Engineering.
  • Moment Formula: M = rF, where abs(M) = abs(r) abs(F) sin(phi).
  • Use the right-hand rule to determine the direction of the moment vector.
• Statics Basics:
  • Statics involves systems with no acceleration; focus is on balancing forces and moments.
  • Tools like CAD SolidWorks or Fusion 360 automate stress calculations; understanding concepts is key.
• Problem-Solving Tips:
  • Draw clear and detailed diagrams, similar to physics problems.
  • Moments need to be taken about a specific point to analyze rotational effects.
• Static Equilibrium:
  • Conditions: (\Sigma \vec{F} = 0), (\Sigma \vec{M} = 0).
  • Break moments into components and solve using 6 equations derived from these conditions.
  • Common axes of motion include:
    • Roll: Rotation along a table.
    • Pitch: Forward/backward tilt.
    • Yaw: Spinning on a surface.
• Loading Conditions:
  • Forces: Point loads.
  • Distributed Loads: Force per unit length.
  • Create free-body diagrams by abstracting the system into simplified forces and moments.

Last updated: 25 January 2025

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