About this Research Topic

Background

The need to validate new technologies and increasingly study more complex structural engineering designs demands new experimental techniques for realistic large scale structural experimentation. Real-time hybrid simulation (RTHS) is a disruptive technology that has evolved over the past twenty years to enable the examination of dynamic systems, especially when traditional testing approaches cannot be employed. However, despite the fact that RTHS has matured considerably in recent years, there are still important gaps in knowledge that prevent its standardization and broad utilization in research and industry. Among these challenges, advancing RTHS methods to readily handle multi-dimensional problems have great potential for enabling more advanced testing and synergistically using existing laboratory facilities that have the capacity for such experimentation. Multiple-actuator or multi-axial RTHS (maRTHS) requires that more than one hydraulic actuator exerts the required motion on experimental specimens demanding the implementation of multiple-input multiple-output (MIMO) control strategies.

In maRTHS, the high internal coupling between hydraulics actuators and the nonlinear kinematics escalate the complexity of actuator control, boundary conditions, and uncertainty considerations. Benchmark problems have been an effective instrument over the past thirty years to explore how to address specific technical challenges while also advancing understanding and promoting capacity building. In the RTHS community, one previous RTHS benchmark control problem was developed based on a single actuator focused on developing tracking controllers for the lateral displacement of a steel frame specimen. Now, for the same relatively stiff steel frame specimen, a new maRTHS benchmark control problem is proposed aiming to elevate the discussion by considering both translation and rotation for tracking control. This seemingly simple, yet fundamental change in the control objectives, considerably transforms the problem and escalates its complexity. The goals of developing this benchmark problem are to:
1) develop, extend, assess, and validate existing control or new MIMO control strategies;
2) provide a computational tool for comparing and contrasting methods for conducting maRTHS;
3) encourage a transition from frequent single-actuator RTHS scenarios to maRTHS experiments; and
4) provide a challenging problem for new researchers to gain experience with maRTHS.

This maRTHS benchmark problem is focused on developing and validate control strategies addressing themes such as:

- Nonlinearities due to kinematics and kinetics transformations and uncertainties.

- Internal coupling among actuators, multi-axial assemblages or couplers, and experimental specimens

- Adaptive and robust control approaches in the frequency and time domain

- Stability of the RTHS from a control perspective

- State and parameter estimation algorithms

Types of manuscripts expected: Original research, hypothesis and theory, methods.

Keywords: RTHS, maRTHS, MIMO control, estimation, uncertainty, coupling, hydraulic actuators, transfer system

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