. Control Systems Simulation Using Matlab and Simulink 1 Introduction 2 Control of Second Order System 2.1 Open loop unit-step response 2.2. (secs) position Step Response of second order system 6 “Hands-on” Design of Control Systems 6.1 Performance Specification 6.2 Feedback Control 6.3 Sampling Time with PID controllers . loop unit-step response 3 Two-mass vibratory system