The Sense, Think, Act Loop
A robot does not see the world continuously. It runs a loop: read the sensors, decide, send a command, then wait for the next tick. How often that loop runs changes what the robot can safely do.
Why the loop rate matters
Between ticks the robot is blind and keeps doing whatever it was told last. At speed \(v\) and loop rate \(f\), it can travel \(v / f\) before it even notices a problem. Then it still needs room to brake with deceleration \(a\):
What to notice
Set the loop rate to 1 Hz and the speed to 3 m/s. The robot notices the wall too late and crashes, even though its stop distance looks safe. Raise the loop rate and the same robot stops in time. The red dots on the track show every place the robot looked.
Real robots run several loops at different rates. A motor controller may run at 1000 Hz, obstacle avoidance at 20 Hz, and route planning at 1 Hz. Fast, simple loops handle safety. Slow loops handle big decisions.