Model-based motion control for multi-axis servohydraulic shaking tables

Research output: Contribution to journalArticle

  • 6 Citations

Abstract

The shaking table is an essential testing tool in the development of earthquake resistant buildings and infrastructure, so improving its performance is an important contribution to saving lives. Currently the bandwidth and accuracy of shaking tables is such that earthquake motion often cannot be replicated with the desired fidelity. A new model-based motion control method is presented for multi-axis shaking tables. The ability of this method to decouple the control axes is demonstrated. A linear parameter varying modal control approach is used – i.e. the modes of vibration of the system are controlled individually, with the modal decomposition repeated at each time step to account for parameter variations. For each mode, a partial non-linear dynamic inversion is performed in the control loop. Feedback is based on a combination of position and acceleration measurements. A command feedforward method is proposed to increase the tracking bandwidth, thus the controller has a two degree-of-freedom structure. Experimental and simulation results are presented for a large (43 tonne total) six degree-of-freedom shaking table. The simulation results are based on a detailed, validated model of the table. Experimental results show that the controller gives exceptional performance compared a conventional proportional controller: for example the horizontal acceleration bandwidth is six-times higher at over 100Hz, which is also many times higher than the hydraulic resonant frequency. These results will allow a step change in earthquake simulation accuracy.
LanguageEnglish
Pages109-122
JournalControl Engineering Practice
Volume53
DOIs
StatusPublished - Aug 2016

Fingerprint

Model-based Control
Motion Control
Motion control
Earthquake
Tables
Earthquakes
Table
Bandwidth
Controller
Controllers
Degree of freedom
Acceleration measurement
Position measurement
Simulation
Resonant Frequency
Feedforward
Hydraulics
Fidelity
Nonlinear Dynamics
Natural frequencies

Keywords

  • shaking table, electrohydraulic servosystem, earthquake simulation, multi-axis control, parallel kinematic mechanism, modal control

Cite this

Model-based motion control for multi-axis servohydraulic shaking tables. / Plummer, Andrew.

In: Control Engineering Practice, Vol. 53, 08.2016, p. 109-122.

Research output: Contribution to journalArticle

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abstract = "The shaking table is an essential testing tool in the development of earthquake resistant buildings and infrastructure, so improving its performance is an important contribution to saving lives. Currently the bandwidth and accuracy of shaking tables is such that earthquake motion often cannot be replicated with the desired fidelity. A new model-based motion control method is presented for multi-axis shaking tables. The ability of this method to decouple the control axes is demonstrated. A linear parameter varying modal control approach is used – i.e. the modes of vibration of the system are controlled individually, with the modal decomposition repeated at each time step to account for parameter variations. For each mode, a partial non-linear dynamic inversion is performed in the control loop. Feedback is based on a combination of position and acceleration measurements. A command feedforward method is proposed to increase the tracking bandwidth, thus the controller has a two degree-of-freedom structure. Experimental and simulation results are presented for a large (43 tonne total) six degree-of-freedom shaking table. The simulation results are based on a detailed, validated model of the table. Experimental results show that the controller gives exceptional performance compared a conventional proportional controller: for example the horizontal acceleration bandwidth is six-times higher at over 100Hz, which is also many times higher than the hydraulic resonant frequency. These results will allow a step change in earthquake simulation accuracy.",
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