In a control loop, sensor feedback is used to compare the actual output to the desired output.

• A. It is never used
• B. It powers the robot
• C. It is used only for data analytics
• D. It is used to compare actual vs desired

Answer: (D)

In a control loop, the point of sensor feedback is to reveal how the actual output differs from what you want. The controller takes that measurement and compares it to the desired value (the setpoint), producing an error signal that tells the system how far off you are. The controller then acts through the actuators to reduce that error, steering the output toward the target. This feedback mechanism—measuring the real state, comparing to the target, and adjusting actions to minimize the difference—is what closes the loop and makes the system regulate itself despite disturbances or model limits. It isn’t about power delivery or just collecting analytics; its primary role is to provide the information needed to keep the actual output aligned with the desired one.