Sensors, I/O & Vision Systems Flashcards

Which type of sensor is most commonly used to measure the rotary position of a robot joint?

Answer: Incremental or absolute encoder

Encoders (incremental or absolute) convert shaft rotation into digital position feedback, providing the precise joint angle data required for robot motion control.

What is the primary purpose of a force/torque sensor mounted at a robot's wrist?

Answer: To detect and respond to contact forces during task execution

A wrist-mounted force/torque sensor measures the forces and moments applied at the tool, enabling compliant motion, assembly tasks, and collision detection.

An inductive proximity sensor will reliably detect which type of target?

Answer: Ferrous or non-ferrous metallic objects

Inductive proximity sensors generate an electromagnetic field and detect eddy currents induced in electrically conductive (metallic) targets only.

In a robotic I/O system, what is the function of a sourcing (PNP) digital output?

Answer: It supplies voltage to the load when active

A sourcing (PNP) output provides the positive supply voltage to the connected load, completing the circuit through the load to the common ground.

What does an absolute encoder provide that an incremental encoder does not?

Answer: A unique position value at every shaft angle without requiring a homing cycle

An absolute encoder outputs a unique digital code for every angular position, so the robot always knows its exact joint angle even after a power loss, eliminating homing.

Which sensor technology is best suited for detecting a transparent glass bottle on a conveyor in a robotic cell?

Answer: Capacitive proximity sensor

Capacitive sensors detect changes in dielectric constant and can sense non-metallic materials including glass, liquids, and plastics that inductive sensors cannot detect.

What is the purpose of the analog-to-digital converter (ADC) in a robotic controller's I/O module?

Answer: To convert continuous voltage or current sensor signals into digital values the controller can process

An ADC samples a continuous analog signal (e.g., 0–10 V from a pressure sensor) and represents it as a discrete digital number that the controller's CPU can read and act on.