Bang-Bang Control in Robotics

What is it?

Bang-bang control is the simplest closed-loop control law: if the measured value is below the setpoint, the actuator is fully on; otherwise it is fully off. It is also called on-off control, two-position control, or hysteresis control.

How it works

The controller compares the measured value to the setpoint. If error is positive, the actuator turns fully on; if error is negative, it turns fully off. To avoid rapid chattering near the setpoint, a hysteresis band is used — the actuator only switches when the error crosses outside a small dead zone around the setpoint.

Real-world example

Your home refrigerator is a bang-bang controller. So is most household heating. In robotics, a simple line-following robot toggles its motors fully left or fully right based on which IR sensor sees the line.

Why it matters for robotics

Bang-bang control is cheap, simple, and good enough for many tasks — perfect for first robotics projects. Indian students often start with bang-bang in their Arduino line-follower before moving to PID.

See also

• Pid Controller
• Feedback Loop
• Closed Loop Control