What is steady-state error and how is it affected by system type?

Steady-state error is the difference between desired and actual output after transients settle. System type (number of integrators in forward path) determines steady-state error for different inputs: Type 0 has constant error to step input, Type 1 has zero error to step but constant error to ramp, Type 2 tracks step and ramp with zero error. Integral action in controllers increases system type. Position, velocity, and acceleration error constants (Kp, Kv, Ka) quantify steady-state errors.