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Decentralised and Centralised Fixed Structure H∞ Robust Loop Shaping for the MIMO Microsurgical Manipulation Based on PSOGSA
(2026-01-01)
Kaitwanidvilai, Somyot
;
Konghuayrob, Poom
;
Aoyama, Hisayuki
This paper presents decentralised and centralised fixed-structure H∞ robust control methods optimised by the Particle Swarm Optimisation and Gravitational Search Algorithm (PSOGSA) for a coupled multi-input multi-output (MIMO) microsurgical manipulator. The design framework explicitly considers uncertainties and disturbance constraints. Conventional H∞ loop-shaping controllers are typically of high order, complex, and difficult to implement in practice. To address this limitation, Proportional-Integral-Derivative (PID)-structured decentralised and centralised H∞ controllers are proposed, providing compact structures while retaining robustness. The novelty of this work lies in embedding H∞ robustness criteria into practical PID-based frameworks, bridging the gap between theoretical robust design and experimental implementation in microsurgical applications. The proposed controllers are evaluated against a reduced-order H∞ controller derived from Hankel norm approximation and a Ziegler–Nichols tuned PID controller, using both simulation and experimental studies. Results demonstrate that the proposed controllers achieve improved stability margins (0.449–0.521 compared with 0.436 for the reduced-order design), maintain low root-mean-square errors (≈0.067–0.089) and remain robust under voltage disturbances where conventional PID control fails. These findings confirm the contribution of a practical and efficient robust control strategy for enhancing the precision and reliability of microsurgical manipulators.
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Hierarchical Co-Ordinated Wide Area and Local Controls of DFIG Wind Turbine and PSS for Robust Power Oscillation Damping
(2016-07-01)
Surinkaew, Tossaporn
;
Ngamroo, Issarachai
In this paper, the two-level hierarchical scheme, which consists of wide area centralized and local controls of the power oscillation damper (POD) installed with the doubly-fed induction generator (DFIG) wind turbine and the power system stabilizer (PSS) has been proposed for robust power oscillation damping. In the wide area level, the centralized POD and PSS has received the input signals from synchronized phasor measurement units (PMUs). The geometric measures of controllability and observability have been applied to select the suitable DFIG and synchronous generator (SG) for stabilizing the target oscillation modes, the proper input signals of the centralized POD and PSS, and the location of PMUs. In the local level, the suitable DFIG and SG have been equipped with POD and PSS, respectively. In the parameters optimization of POD and PSS, the practical issues such as damping performance, controller structure, communication latency, and robustness against system uncertainties have been considered. The controller efficiency and resiliency of the proposed controller have been evaluated in comparison with other controllers by eigenvalue analysis and nonlinear simulation for a wide range of operating conditions, line outage contingencies, severe faults, and communication failure.
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Robust stabilization of multimachine power system by DFIG wind turbine equipped with power oscillation damper
(2014-10-15)
Surinkaew, Tossaporn
;
Ngamroo, Issarachai
Various system uncertainties and disturbances may cause the power system instability. The power system stabilizing controller designed without taking such uncertainties into account may not tolerate and fail to operate. This paper aim at the new robust control design of power oscillation damper (POD) equipped with the doubly-fed induction generator (DFIG) wind turbine. Without difficulty of mathematic modeling, the inverse output multiplicative perturbation is used to represent system uncertainties. The structure of POD is specified as a practical 2nd-order lead/lag compensator with single input. The POD parameters optimization problem is formulated considering the variation of tie-line power flows. The POD parameters are automatically tuned by firefly algorithm so that the damping performance and robustness can be achieved. Simulation results in IEEE 9 bus test system ensure that the proposed robust POD is superior to the conventional POD in terms of the damping performance and robustness.
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Wide area robust centralized power oscillation dampers design for DFIG-based wind turbines
(2014-02-10)
Surinkaew, Tossaporn
;
Ngamroo, Issarachai
Inter-area oscillations are associated with machines in one part of the system oscillating against machines in other parts of the system. They are caused by two or more groups of machines that are interconnected by weak ties. To damp out the inter-area oscillations, this paper proposes the new application of wide area stability control for robust centralized power oscillation dampers (PODs) design of doubly-fed induction generator (DFIG) wind turbines. The POD with 2<sup>nd</sup>-order lead/lag compensator structure for each DFIG wind turbine is located at the control center. To stabilize the target inter-area mode effectively, the geometric measures of controllability and observability are used to choose the suitable DFIG wind turbine for stabilizing the target oscillation mode, the proper input signal of POD, and the location of phasor measurement units (PMUs). The input signal of each POD is obtained from PMU while the output signal is transmitted to the rotor side converter voltage controller of DFIG. As a result, the reactive power output of DFIG can be modulated to damp out inter-area oscillations. In the POD parameters optimization, the wide range of power output levels of DFIGs and synchronous generators, time delays due to wide area communication, and unstructured system uncertainties model are taken into account so that the damping of inter-area modes and the system robust stability margin against uncertainties can be guaranteed. Solving the problem by the firefly algorithm automatically, the optimal parameters of PODs can be achieved. The stabilizing performance and robustness of the proposed robust centralized POD are evaluated in the IEEE New England 39 bus system by eigenvalue analyses and nonlinear simulation in scenarios with severe short circuits, N-1 outage contingencies, heavy power flows, and line tripping.
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Coordinated robust control of DFIG wind turbine and pss for stabilization of power oscillations considering system uncertainties
(2014-01-01)
Surinkaew, Tossaporn
;
Ngamroo, Issarachai
Uncertainties in power systems, such as intermittent wind power, generating and loading conditions may cause the malfunction of power system stabilizing controllers, which are designed without considering such uncertainties. To enhance the robustness of stabilizing controllers against system uncertainties, this paper proposes a new coordinated robust control of doubly fed induction generator (DFIG) wind turbine equipped with power oscillation damper (POD) and synchronous generator installed with power system stabilizer (PSS) for stabilization of power system oscillations. Without the difficulty of mathematical representation, the inverse output multiplicative perturbation is used to model system uncertainties. The structure of POD and PSS is specified as a practical second-order lead/lag compensator with single input. The parameters optimization of POD and PSS is conducted so that the stabilizing performance and robustness of POD and PSS are augmented. The improved firefly algorithm is applied to solve the optimization problem and achieve the POD and PSS parameters automatically. Simulation study in the modified IEEE-39 bus New England system included with DFIG wind turbines ensures that the robustness and stabilizing performance of the proposed coordinated DFIG with POD and PSS are much superior to those of the conventional DFIG with POD and PSS under various severe disturbances and system uncertainties. © 2014 IEEE.
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Robust control design for three-phase power inverters using genetic algorithm
(2011-08-12)
Nimpitiwan, N.
;
Kaitwanidvilai, S.
This paper proposes a new technique to design a fixed-structure robust controller for grid connected inverter systems. The proposed technique applies the Genetic Algorithm to evaluate the optimal controller parameters. The integral squared error (ISE) of the controlled system is minimized and the robust performance (RP) of the system is satisfied. In the proposed design, the structure of controller is specified as a decentralized PI controller which is preferred for practical implementations. Simulation results show that the proposed technique is promising. © 2011 IEEE.
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GPS synchronized phasor measurement units-based wide area robust PSS parameters optimization
(2011-01-01)
Nandar, Cuk Supriyadi Ali
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Ngamroo, Issarachai
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Dechanupaprittha, Sanchai
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Watanabe, Masayuki
;
Mitani, Yasunori
This paper proposes an optimization method of wide area robust power system stabilizer (PSS) using global positioning system (GPS) synchronized phasor measurement units (PMUs). Assuming multiple PMUs are located in an interconnected power system, the steady-state phasor data are obtained by applying the small load perturbation. Based on the phasor data, the coupled vibration model (CVM) included with the PSS can be established and applied to estimate the dominant inter-area oscillation modes. In the robust PSS (RPSS) optimization, unstructured system uncertainties such as various generating and loading conditions, variation of system parameters etc. are represented by the inverse additive perturbation and included in the CVM. To enhance the system robust stability margin, the optimization of PSS parameters is carried out in the CVM. The genetic algorithm (GA) is applied to solve the problem and achieve the PSS parameters automatically. Simulation studies in the IEEJ Western Japan 10-machine power system confirm that the robustness of the proposed PSS is much superior to that of the compared PSS against various operating conditions and fault locations. © 2010 John Wiley & Sons, Ltd.

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