Simulink Control Design™ - MathWorks

• User comfort defined from road disturbance to body acceleration.


• Reasonable control bandwidth.

The nominal values of spring constant and damper between the body and the wheel

assembly are not exact and due to the imperfections in the materials, these values can be

constant but different. Try to satisfy these control objectives under parameter variations.

Model the road disturbance of magnitude seven centimeters and use the constant weight.

Wroad = ss(0.07);

Define the closed-loop target for handling from road disturbance to suspension deflection

as

HandlingTarget = 0.044444 * tf([1/8 1],[1/80 1]);

Define the target for comfort from road disturbance to body acceleration as

ComfortTarget = 0.6667 * tf([1/0.45 1],[1/150 1]);

Limit the control bandwidth by the weight function from road disturbance to the control

signal

Wact = tf(0.1684*[1 500],[1 50]);

Explanation on selecting the closed-loop targets and the weight function is given in the

example “Robust Control of an Active Suspension” (Robust Control Toolbox)

Controller Tuning

Double click to the orange block in Simulink model to open the Control System Tuner

session for active suspension control. Tuned block is set to the second order Controller

and three tuning goals are defined to achieve the handling, comfort and control

bandwidth as described above. In order to see the performance of the tuning, the step

responses from road disturbance to suspension deflection, body acceleration and control

force are plotted.

Handling, Comfort and Control Bandwidth goals are defined as gain limits,

HandlingTarget/Wroad, ComfortTarget/Wroad and Wact/Wroad. All gain functions

are divided by Wroad to incorporate the road disturbance.

13 Control System Tuning Examples