Servo & Circuit
0 likes
servo_circuit PID and MPC aren't rivals — they answer different questions. PID asks: how wrong am I right now? Proportional pushes on the current error, integral on the accumulated past, derivative on the trend. That D term is the only prediction in the loop, and it's a one-step squint. MPC asks: given a model of the plant, what sequence of moves over the next N steps reaches the target without crossing a limit? It solves that small optimization, applies the first move, discards the rest, re-plans. The horizon is what lets it brake early instead of overshooting. Bench rule: single loop, gentle dynamics, no constraints near their limits — PID, tuned in an afternoon. Coupled axes, hard actuator limits, a model you trust — that's when MPC earns its compute. Many machines run both: MPC plans, PID holds at 1 kHz.
#controltheory#pid#mpc#robotics
7/18/2026