Jan C. Willems

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World Congress in Prague on July 4, 2005, Rudy Kalman articulated a principle that resonated very well with me. He put forward the following paradigm for research domains that combine models and mathematics: 1) Get the physics right. 2) The rest is mathematics. Did we, system theorists, get the physics right? Do our basic model structures adequately(More)
We define feedforward control as a control policy in which the exogenous disturbances are known for all time at the moment when the control is applied. It is shown that disturbance decoupling by feedforward control is possible iff it is possible by PID control or iff approximate disturbance decoupling by state feedback is possible.
It is shown that foi linear dynamical systems with quadratic supply rates, a storage function can always be written as a quadratic function of the state of an associated linear dynamical system. This dynamical system is obtained by combining the dynamics of the original system with the dynamics of the supply rate. @ 1997 Elsevier Science B.V.