Control of linear systems; Delay-based controllers; PID control; Stability Closed loop control systems; Control system stability; Delay control systems; Linear control systems; Three term control systems; Two term control systems; Control of linear system; Control schemes; Delay-based controller; Geometric approaches; LTI systems; Proportional integral; Proportional integral controllers; Proportional-integral control; Second orders; Tuning rules; Proportional control systems