Fixed Structure Robust Loop Shaping Controller for a Buck-Boost Converter Using Evolutionary Algorithm

The H∞ loop shaping method and fixed-structure H∞ method are employed to design controllers of a quadrotor. The validity of these two controllers is verified by numerical simulations, and it is observed that both the methods can achieve the design requirements and have a well tracking performance and restraining noise performance. Compared to H∞ loop shaping controller, the fixed-structure H∞ controller has not only the general nature based on h-infinity theory, but also takes into account easy realization.

Design of Robust Power System Stabilizer using Genetic Algorithm-based Fixed-Structure H∞ Loop Shaping Control

H loop-shaping control is an excellent strategy, in which control performance and closed-loop stability can be both guaranteed. To use the H loop-shaping control in the multiple model framework to develop a multiple model-based H loop-shaping control method, in which local linear model selection and local controller design are integrated in the multiple model dividing procedure. Therefore, local model redundancy can be avoided and controller structure can be simplified. Besides, desired local control performance and stability are guaranteed by shaping functions. A TITO process is studied. Closed-loop simulation demonstrates the effectiveness of the proposed multiple model-based H loop-shaping method.

An H/sub /spl infin// controller is designed for a latax autopilot missile, using the method of loop shaping and the central K algorithm of McFarlane and Glover (1989). The resulting autopilot is shown to have good robustness to variations in incidence and roll angle.

In this study a novel robust approach for proportional integrative derivative gain evaluation is proposed. This approach, which can be considered in the class of H∞ loop shaping methods, is applied to tune the gains of a multi-loop autopilot for mini unmanned aerial vehicles. Nominal stability, nominal performance, robust stability and robust performance of the system are assessed. Root locus method and loop shaping techniques are combined in order to guarantee compliance with robustness requirements and to obtain satisfying flying qualities. Simulation results demonstrate that the method is easy to implement, good robustness and flying performances can be achieved despite a conflicting requirement between these two characteristics.

SUMMARYTheH∞loop shaping method is known as one of the robust controller design methods. In this method, the design procedure consists of two steps: the weight design and the derivation of a controller. The controller is derived for the weighted plant to suppress theH∞norm of the transfer matrix consisting of a sensitivity function, a complementary sensitivity function, and so on. Therefore, the closed‐loop system achieves good tracking and robustness. However, there is only a guideline for the weight design, and an explicit design index of the weight has not been given. As a result, a time‐consuming and tedious process is often required to tune the weight. This paper provides a new weight design method for a stable single‐input single‐output (SISO) plant. The resulting weight guarantees the upper bound of the performance level before the controller design. This means that the controller design and the weight design are completely separated in contrast to the Lanzon's work. Moreover, the weight is designed using only frequency responses. Accordingly, we can avoid the process of the system identification and reduce the conservativeness caused by an overestimate of the system uncertainty.

The authors investigate the observation that the loop shaping design procedure of D.C. McFarlane and K. Glover (1990) can lead to designs which exhibit good levels of robust performance. An alternative loop shaping procedure which incorporates mu -synthesis robust stabilization is given. The relationship between these two loop-shaping design methods and conventional non-loop shaping mu -synthesis robust stabilization is examined.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Sloshing analysis and suppression control of tilting-type automatic pouring machine

The H/sub /spl infin// loop shaping design method is an effective way to design robust controllers. One of the main limitations in the design of H/sub /spl infin// loop shaping controllers is that the design method is based on frequency domain specifications that do not precisely represent the underlying time domain performance requirements. Even if the time response constraints were not present, the approach is based on trial and error selection of the frequency dependent weights that are used in the design. Selection of these functions becomes more difficult if time response constraints must be satisfied. This paper presents a systematic way of selecting the loop parameters for the frequency-dependent weights and develops a fuzzy algorithm that selects these parameters so that the resulting H/sub /spl infin// loop shaping controller yields a closed loop system that satisfies the time response constraints for a single-input single-output system.

The Particle swarm optimization (PSO) approach is an efficient meta-heuristic search method that can be used to solve the multi-objective and non-convex optimization problems that are normally generated when designing structure-specified H∞ loop shaping controllers. In this study, PSO is used to design the controllers able to balance a bicycle robot, with a model-based systematic procedure for the controller design being proposed. Simulation and experimental results are presented that show that superior robustness and efficiency properties were obtained using the structure-specified H∞ loop shaping controllers compared to those obtained using the proportional plus derivative as well as conventional H∞ loop shaping ones. In comparison with the solutions obtained based on genetic algorithms, the use of PSO has a better efficiency in term of the computational time.

Effective force testing (EFT) is one of the force-based experimental methods for performance evaluation of structures that incorporate dynamic force control using hydraulic actuators. While previous studies have shown successful implementations of force control, controllable frequency ranges are limited to low frequencies (10 Hz). This study presents the EFT method using a robust loop shaping force feedback controller that can extend the frequency range up to 25 Hz. This study investigates the dynamic properties of hydraulic actuators and the design of a loop shaping controller that compensates for control-structure interaction as well as suppresses the effect of oil-column resonance. The designed loop shaping controller was successfully implemented into an EFT setup at the Johns Hopkins University. An experimental investigation was performed with linear and nonlinear test structures. Results showed that the loop shaping controller provided excellent force tracking performance as well as robustness for dynamic force loadings.

Fixed structure [formula omitted] loop shaping control of switched reluctance motor for electrical vehicle

In this paper, we aim to stabilize the unstable system by loop shaping method with H <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sup> controller. Moreover after stabilizing the system we need to modify the system which is unstable due to time-delay element by Internal Model Controller considering the uncertainty of control object and time-delay element. Time-delay will happen during the long distance communication. Therefore, when control object is located in long distance, the transmitted reference signal will be delayed certainly. For this reason even though we stabilize the control object by loop-shaping, it will be an unstable system by time-delay elements. In this paper we consider an unstable control object such as ballistic missile. Generally, missiles are required be controlled from long distance. Therefore we stabilize the control object with H <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sup> controller and later compensate the system which is unstable due to time-delay element by Internal Model Controller.

The H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> loop shaping method is known as one of the robust controller design method achieving good control performance and robustness. In this method, the final controller consists of weighting functions and a stabilizing controller. Control performance based on the open-loop shaping is decided by designing of weighting functions. However, if weighting functions are not suitable, the stabilizing controller may change the gain characteristic of the open-loop function to improve robust stability margin. In this case, design of weighting functions is often required in terms of achieving desired performance. Moreover, this method takes much time to build a mathematical model of an actual plant and its uncertainty. This paper proposes a low-order weighting function design method using only frequency responses for MIMO (Multi-Input-Multi-Output) systems. These weighting functions guarantee the desired performance level of the designed controller. Therefore, the time-consuming process is reduced. The effectiveness of the proposed method is verified through the experiment.

A conventional spin-stand system which used to evaluate read-write performance of magnetic recording heads and media can not allow thermal drift of its mechanism and NRRO (non-repeatable run out) of its air spindle motor. Therefore, we proposed a precise track following actuator which applied the spin-stand to construct a piggyback system. The actuator called Nano Motion Actuator (NMA) by the authors consists of a piezoelectric element and a displacement amplifying mechanism. In this paper, a design method of a PID controller to realize a specified gain crossover frequency for the NMA is proposed. At first, we discussed about a model matching problem of an open loop transfer function and decided PID gains from physical parameters of the NMA. Next, based on a loop shaping method, the properties of the frequency response of the open loop transfer function were improved. The effectiveness of the proposed method is illustrated by the simulation results and experimental results.