# Soft Variable Structure Control in Sampled-Data Systems with Saturating Input

### Przemyslaw Ignaciuk, Michał Morawski

#### Abstract

In the effort to achieve high convergence rate, at the same time avoiding implementation difficulties and poor robustness of time-optimal controllers, the concept of soft Variable Structure Control (VSC) may be applied. The classical formulation of soft VSC in continuous time domain assumes smooth switching among an infinite number of controllers. Since nowadays control laws are implemented digitally, changing the control structure is limited to sampling instances, which leads to quasi-soft VSC. The paper investigates how the favourable characteristics of dynamic soft VSC can be extended to input-constrained systems with finite sampling. The design procedure and stability analysis are conducted directly in discrete time domain. The resulting nonlinear control law is synthesised into a form substantially different from its continuous-time counterpart. However, smooth control action and fast convergence of continuous soft VSC is retained. The properties of the obtained control system are formally proved and confirmed experimentally.

#### References

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#### Paper Citation

#### in Harvard Style

Ignaciuk P. and Morawski M. (2016). **Soft Variable Structure Control in Sampled-Data Systems with Saturating Input** . In *Proceedings of the 13th International Conference on Informatics in Control, Automation and Robotics - Volume 1: ICINCO,* ISBN 978-989-758-198-4, pages 545-550. DOI: 10.5220/0006001205450550

#### in Bibtex Style

@conference{icinco16,

author={Przemyslaw Ignaciuk and Michał Morawski},

title={Soft Variable Structure Control in Sampled-Data Systems with Saturating Input},

booktitle={Proceedings of the 13th International Conference on Informatics in Control, Automation and Robotics - Volume 1: ICINCO,},

year={2016},

pages={545-550},

publisher={SciTePress},

organization={INSTICC},

doi={10.5220/0006001205450550},

isbn={978-989-758-198-4},

}

#### in EndNote Style

TY - CONF

JO - Proceedings of the 13th International Conference on Informatics in Control, Automation and Robotics - Volume 1: ICINCO,

TI - Soft Variable Structure Control in Sampled-Data Systems with Saturating Input

SN - 978-989-758-198-4

AU - Ignaciuk P.

AU - Morawski M.

PY - 2016

SP - 545

EP - 550

DO - 10.5220/0006001205450550