Soft Variable Structure Control of Linear Systems via Desired Pole Paths


  • Mojtaba Kaheni Shahrood University of Technology, Shahrood, Iran.
  • Mohammad Hadad Zarif Shahrood University of Technology, Shahrood, Iran.
  • Ali Akbarzadeh Kalat Shahrood University of Technology, Shahrood, Iran.
  • Mohammad Sami Fadali University of Nevada, Reno, USA.



Circle criterion, Desired pole paths, Linear control, Nonlinear control, Variable structure control


In this article, a novel method of soft variable structure control of linear systems, desired pole paths, is proposed. The proposed method is helpful to reach a fast response when a continuous control signal and satisfaction of some constraints are desired. The method selects a desired path for closed loop poles instead of the exact location of poles, then the pole placement in this path is determined by solving an optimization problem subject to a control signal constraint leading to a suboptimal control structure. The stability of the proposed method is provided based on the multivariable circle criterion and the Kalman-Yakubovich-Popov lemma. A design parameter is also introduced in this paper which can adjust a tradeoff between speed of response and smoothness of the control signal. Simulation of a satellite model shows an improvement in shortening the settling time and softening the control signal compared to published soft variable structure control schemes.