Demonstration of structural changes in variable structure control using state space approach

This paper demonstrates structural changes in variable structure control. A second order open loop unstable system was used as an illustrative example to demonstrate the structural changes; the system has real, positive open loop eigenvalues. A change of system eigenvalues implies a change of system structure. A structure may have properties such as being stable or unstable, fast/sluggish response, and insensitive to all inputs including disturbances. Thus the strategy of variable structure control is to provide the system with a means of switching from one structure to another with a view to exploiting the useful properties available in both structures. The bonus is that it is possible to arrive at a completely different lower order-structure which is totally insensitive to disturbances and internal parameter uncertainties.