Seshadhri Srinivasan

Questions and Answers (6) View all

• Answer added in Control Systems Engineering
  17 Robustness of a control scheme
  By Joseph Ho · University of Malaya
  Seshadhri Srinivasan · ABB

  Generally robustness of a controller is not directly measured. What is measured is the robustness of the closed loop system with controller. There are... [more]

  Generally robustness of a controller is not directly measured. What is measured is the robustness of the closed loop system with controller. There are four things in it: 1. Nominal stability, 2. Nominal performance, 3. Robust stability and 4. Robust performance. Usually the complexity of achieving a controller performance increases in the ascending order of the performance indicated. There is an usual assumption on the perturbation like infinite norm of the perturbation does not increase more than 1 in magnitude and is the only assumption. Then controller design proceeds. Nominal stability and performance is what a controller achieves usually. Then you consider perturbation in the model and design a controller. There are various methods available then to design the controller. Simplest ones are loop shaping approaches to computationally intensive H-infinity methods. Hope this helps.
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• Answer added in Control Systems Engineering
  8 How can I find the controllability conditions or controllability distribution for discrete time nonlinear state-space system?
  By Mohammad Yeganegi · Shahid Chamran University of Ahvaz
  Seshadhri Srinivasan · ABB

  First for discrete time system... it matters how you find the discretized version. If you are using an Euler method with H.o.T. eliminated- it is equi... [more]

  First for discrete time system... it matters how you find the discretized version. If you are using an Euler method with H.o.T. eliminated- it is equivalent to using Zero Order Hold... most of the properties of linear systems are retained and you can use the controllability tests for linear systems to ascertain the stability. If you are discretizing using Trapezoidal or other methods... you need to linearize around different points and then study controllability. Let me know if this helps you.
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• Answer added in Control Systems Engineering
  17 Robustness of a control scheme
  By Joseph Ho · University of Malaya
  Seshadhri Srinivasan · ABB

  For stochastic case try using Linear Parameter Varying system depending of the parameter variations. Then having some polytopic approximation will sol... [more]

  For stochastic case try using Linear Parameter Varying system depending of the parameter variations. Then having some polytopic approximation will solve the problem.
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• Answer added in Control Systems Engineering
  1 Supervisory Control Theory
  By Marcelo Teixeira · Universidade Federal de Santa Catarina
  Seshadhri Srinivasan · ABB

  I am not sure if my understanding is right. I will suggest using hybrid systems approach. The states and transitions can be used for mapping your cond... [more]

  I am not sure if my understanding is right. I will suggest using hybrid systems approach. The states and transitions can be used for mapping your conditions.
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