The use of digital twins to remotely update feedback controllers for the motion control of nonlinear dynamic systems
The use of digital twins to remotely update feedback controllers for the motion control of nonlinear dynamic systems
The use of a digital twin to update a feedback controller is considered, and this is illustrated using simulations of a position-controlled dynamical system with a time-varying nonlinear element. The feedback control system consists of a dc motor driving the displacement of a three degree of freedom structure through a lead screw that is subject to backlash, whose gap angle changes over time due to wear for example. The backlash is shown to destabilise the feedback loop when using a PID controller designed for the linear system. However, stability can then be re-established by including a dead zone within the controller. The design of the dead zone depends on the extent of the gap angle in the backlash and is a trade-off between stabilising the system and avoiding excessive steady-state errors and undesired transient behaviour. When the backlash gap angle changes significantly from the one used to design the dead zone, both performance and stability are affected. Therefore, a digital twin of the system is used to estimate the backlash gap angle as it changes with time and this estimate is used to re-design the dead zone, which is then communicated back to update the controller. The digital twin and controller-design process can be implemented offline and remotely from the physical twin and the real-time controller via an asynchronous link with variable time delays. As a result of combining the feedback loop and digital twin, good performance and stability are maintained at all times.
Adaptive control, Backlash, Dead zone controller, Digital twin, Reconfigurable feedback controller
Vered, Yoav
c13938de-457b-4e25-b57b-7471c7bc832a
Elliott, Stephen J.
721dc55c-8c3e-4895-b9c4-82f62abd3567
15 February 2023
Vered, Yoav
c13938de-457b-4e25-b57b-7471c7bc832a
Elliott, Stephen J.
721dc55c-8c3e-4895-b9c4-82f62abd3567
Vered, Yoav and Elliott, Stephen J.
(2023)
The use of digital twins to remotely update feedback controllers for the motion control of nonlinear dynamic systems.
Mechanical Systems and Signal Processing, 185, [109770].
(doi:10.1016/j.ymssp.2022.109770).
Abstract
The use of a digital twin to update a feedback controller is considered, and this is illustrated using simulations of a position-controlled dynamical system with a time-varying nonlinear element. The feedback control system consists of a dc motor driving the displacement of a three degree of freedom structure through a lead screw that is subject to backlash, whose gap angle changes over time due to wear for example. The backlash is shown to destabilise the feedback loop when using a PID controller designed for the linear system. However, stability can then be re-established by including a dead zone within the controller. The design of the dead zone depends on the extent of the gap angle in the backlash and is a trade-off between stabilising the system and avoiding excessive steady-state errors and undesired transient behaviour. When the backlash gap angle changes significantly from the one used to design the dead zone, both performance and stability are affected. Therefore, a digital twin of the system is used to estimate the backlash gap angle as it changes with time and this estimate is used to re-design the dead zone, which is then communicated back to update the controller. The digital twin and controller-design process can be implemented offline and remotely from the physical twin and the real-time controller via an asynchronous link with variable time delays. As a result of combining the feedback loop and digital twin, good performance and stability are maintained at all times.
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Preprint_The use of digital twins to remotely update feedback controllers for the motion control of nonlinear dynamic systems
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More information
Accepted/In Press date: 4 September 2022
e-pub ahead of print date: 21 September 2022
Published date: 15 February 2023
Additional Information:
Funding Information:
The authors gratefully acknowledge the support of the UK Engineering and Physical Sciences Research Council (EPSRC) through the DigiTwin project (grant EP/R006768/1).
Publisher Copyright:
© 2022 The Author(s)
Keywords:
Adaptive control, Backlash, Dead zone controller, Digital twin, Reconfigurable feedback controller
Identifiers
Local EPrints ID: 471200
URI: http://eprints.soton.ac.uk/id/eprint/471200
ISSN: 0888-3270
PURE UUID: 019aedc1-436a-43cd-9f2f-a3b9f349ab5e
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Date deposited: 31 Oct 2022 17:44
Last modified: 16 Mar 2024 22:27
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Author:
Yoav Vered
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