Reading: Read Real Robots Don’t Drive Straight
Reminder: Readings are your responsibility. You will be expected to come to class prepared, having read the material, and ready to participate in the discussion
Logistics
- Let’s do the post-it-note exercise
- Lets talk about the use of ChatGPT to produce code
- James asked in Lab last week, why not just use the PID algorithm that is provided by ChatGPT
- Further discussion…
- Note about due dates for all assigments. There is always a 3 day grace period.
- About the reading for today: CLick Here
How do Robots Perceive? Sensors
- What is a sensor? Is a sensor an input or output device?
- What happens to the sensing information
- How is it stored and detected and acted upon?
Types of Sensors
- Is a sensor an input or output device?
- Proprioception
- Is a keyboard a sensor?
- Is a joystick a sensor?
- Is a map a sensor?
- Active Vs. Passive
- Sensor Fusion
What do all sensors have in common?
- They generate a stream of data
- They have an electrical connection to the computer onboard the robot
- Usually it is to the microcontroller because of real time capability
- Software on the microcontroller (e.g, arduino) is called firmware
- Firware does some processing of the data (case by case)
- Delivers it to the SBC (Single Board Computer, e.g. Rasberry Pi) in the form of topics published
What kinds of electrical connections?
- Very dependent on the sensor
- Analog and Binary pins
- I2C Bus
- And others
- Almost always there is an arduino library to interface
Lidar
- What is a Lidar
- What does it look like and how does it work?
- “Time of travel” or “Time of Flight”
- What does the data look like?
Subtleties
- What do the directions mean?
- Are the directions absolute or relative?
- What if the robot is not pointing to where you think?
- Do they go clockwise or counterclockwise?
- Lets look at the data!
- It’s not clean! (This is typical for all sensors)
- It is not accurate!
- It’s sometimes wildly inaccurate
- It is constantly flooding in
Breakout (15 Minutes)
- Documentation for LaserScan Data
- Given
- angle_min = 0 # exactly forward
- angle_max = 359 (deg)
- range_min = 0.12 (m)
- range_max = 3.5 (m)
- With your teammates write a few lines of python
- Set the variable wall_ahead to true or false
- One or two lines of python
- True means that there’s an obstacle ahead at < 0.3 m
GPS
Motor (encoder)
- How it works
- Key characteristics or features
- What data it provides
Camera
- How it works
- Key Characteristics or features
- What Data it provides
Depth Camera
- How it works
- Key Characteristics or features
- Example ToF Camera
- What data it provides
Ultra Sonic Sensor
Bumper sensors
- How it works
- Key Characteristics or features
- Example: Bumper Sensopr
- What data it provides
IMU - Inertial Measurement Unit
- Acceleration: dynamic and static (as in gravity)
- See Accelerometer, Gyro, IMU buying guide
- Gyro: Angular velocity - how fast spinning around an acciss
- Can have them independently or combined into an IMU
Thank you. Questions?
(random Image from picsum.photos)