6. Configuring the Stiffness of the Spring (Control Design and Simulation Module)

Before you run the simulation again, you must configure the stiffness of the simulated spring. Complete the following steps to configure this Simulation function.

1. Double-click the Stiffness function to display the configuration dialog box.
2. Enter 100 in the gain numeric control. This value represents a stiffness of 100 Newtons per meter.
3. Click OK to return to the simulation diagram. Notice that the Stiffness function displays 100.
4. Display the front panel and ensure the Force control is set to -9.8 and the Mass control is set to 1.
5. Run the simulation. The Velocity and Position charts display the behavior of the mass as the spring oscillates.
   
   The front panel now resembles the following image.
   
   

   

   
   
   Notice the new behavior compared to the last time you ran the simulation. This time, the velocity and position do not constantly decrease. Both values oscillate, which is how a spring behaves in the real world.
6. Change the value of the Mass control to 10 and run the simulation again. Notice the different behavior in the Velocity and Position charts. The 10 kg mass forces the spring to oscillate less frequently and within a smaller velocity/position range.