ITSE (integral time squared error) evaluates a control response by integrating time multiplied by squared error: ITSE = ∫ t e(t)² dt. The time factor penalizes errors that persist, while squaring emphasizes larger deviations. In PID tuning, this makes later errors especially costly and can favor responses with slower rise times but more oscillation. section 8.7
PID step-response evaluation
For a unit-step response, calculate error as the difference between the desired output and actual output, square the sampled error, multiply by time, and approximate the integral numerically with the trapezoidal rule. A genetic algorithm can then minimize this value while searching for Kp, Ki, and Kd. section 8.7
