CRE CRE Sensors, Vision & Perception 1 — Questions and Answers
Question 1: A rotary encoder mounted on a robot joint primarily measures:
- Joint operating temperature
- Joint angular position or displacement (Correct answer)
- Motor winding current
- Applied joint torque
Correct answer: Joint angular position or displacement
Encoders convert mechanical rotation into electrical pulse counts, providing the controller with precise joint position feedback.
Question 2: A force/torque sensor mounted at the robot's wrist is used to:
- Measure ambient environmental temperature
- Detect contact forces and moments during manipulation or assembly (Correct answer)
- Track end-effector linear velocity
- Calibrate joint encoder offsets
Correct answer: Detect contact forces and moments during manipulation or assembly
Wrist-mounted force/torque sensors measure all six components of contact forces and moments, enabling compliant control and safe contact detection.
Question 3: LiDAR sensors measure distance by:
- Capturing and comparing stereo image pairs
- Emitting laser pulses and measuring their round-trip time of flight (Correct answer)
- Emitting ultrasonic sound waves
- Detecting changes in magnetic field strength
Correct answer: Emitting laser pulses and measuring their round-trip time of flight
LiDAR calculates range by precisely timing the interval between emitting a laser pulse and receiving its reflection from a surface.
Question 4: An Inertial Measurement Unit (IMU) combines which two sensor types?
- Camera and microphone
- Accelerometers and gyroscopes (Correct answer)
- Force sensors and encoders
- Ultrasonic and infrared sensors
Correct answer: Accelerometers and gyroscopes
IMUs integrate accelerometers measuring linear acceleration with gyroscopes measuring angular rate to estimate orientation and motion state.
Question 5: Proximity sensors in industrial robot cells are most commonly used for:
- Measuring surface temperature of workpieces
- Detecting object presence without physical contact (Correct answer)
- Capturing high-resolution surface images
- Measuring joint reaction torques
Correct answer: Detecting object presence without physical contact
Proximity sensors detect nearby objects using inductive, capacitive, or optical principles, triggering signals without requiring physical contact.
Question 6: Which sensor type is best suited for measuring precise 3D surface profiles of workpieces in manufacturing?
- IMU
- Structured light scanner or laser profilometer (Correct answer)
- Thermocouple
- Barometric pressure sensor
Correct answer: Structured light scanner or laser profilometer
Structured light systems and laser profilometers project known patterns onto surfaces and triangulate point positions to reconstruct accurate 3D geometry.
CRE CRE Sensors, Vision & Perception 1
A rotary encoder mounted on a robot joint primarily measures: