Plot the effect of proportional (Kp), integral (Ki), and
derivative (Kd) gains to a step-change in an error signal, e(t). At
least make three plots (1-3), each containing three graphs:
1. Graph 1 High Kp; graph2: medium Kp; graph 3: low Kp
2. Graph 1: Low Kd; Graph 2: medium Kd; Graph 3: high Kd
3. Graph 1: High Kp and Ki; Graph 2: medium Kp, Ki, and Kd;
Graph 3: low Kp and Ki