Multi-input Controller Research Articles

Data-driven control for multi-rate multi-input/single-output systems

For the next generation of manufacturing, represented by Industrie 4.0, a multi-input controller is designed directly from controlled data, without using the mathematical plant model, where the ratio between the D/A conversion of multiple inputs and the A/D conversion of a single output is non-uniquely. With the proposed method, the fixed-structured controller is optimally designed by solving a model reference problem using one-shot data. Furthermore, to eliminate inter-sample ripples emerged by input oscillation, the deviation of the control inputs is also evaluated using the proposed method. As a result, a non-ripple data-driven controller is achieved. Numerical examples show that the proposed multi-rate data-driven method is superior than the conventional single-rate method.

Modeling and Control of a Diesel Engine With Regenerative Hydraulic-Assisted Turbocharger

Diesel engines are of great challenges due to stringent emission and fuel economy requirements. Compared with the conventional turbocharger system, regenerative assisted system provides additional degrees-of-freedom for turbocharger speed control. Hence, it significantly improves control capability for exhaust-gas-recirculation (EGR) and boost pressure. This paper focuses on modeling and control of a diesel engine air-path system equipped with an EGR subsystem and a variable geometry turbocharger (VGT) coupled with a regenerative hydraulic-assisted turbocharger (RHAT). The challenges lie in the inherent coupling among EGR, turbocharger performance, and high nonlinearity of the engine air-path system. A control-oriented nonlinear RHAT system model is developed; and a linear quadratic (LQ) control design approach is proposed in this paper to regulate the EGR mass flow rate and boost pressure simultaneously and the resulting closed-loop system performance can be tuned by properly selecting the LQ control weighting matrices. Multiple LQ controllers with integral action are designed based on the linearized system models over a gridded engine operational map and the final gain-scheduling controller for a given engine operational condition is obtained by interpreting the neighboring LQ controllers. The gain-scheduling LQ controllers for both traditional VGT-EGR and VGT-EGR-RHAT systems are compared with the in-house baseline controller, consisting of two single-input and single-output (SISO) controllers, against the nonlinear plant. The simulation results show that the designed multi-input and multi-output LQ gain-scheduling controller is able to manage the performance trade-offs between EGR mass flow and boost pressure tracking. With the additional assisted and regenerative power available on the turbocharger shaft for the RHAT system, engine transient boost pressure performance can be significantly improved without compromising the EGR tracking performance, compared with the baseline control.

Reduced-order modeling and feedback control of a flexible wing at low Reynolds numbers

A state-space reduced-order model for the lift generated by the unsteady deflection of a two-dimensional flexible wing is presented. The wing’s deflection is decomposed using a truncated Fourier series in the contribution of single deflection modes; the global lift is then obtained using superposition. The presented model is an extension of the model introduced in Brunton et al. (2013) for rigid pitching and plunging. A realization of the model is obtained using lift pulse responses from Direct Numerical Simulation (DNS) at a Reynolds number of 100. The performance of the deflection modes are discussed from a feedback control point of view and controllers for mode 1, mode 2 and pitching are designed using loop-shaping techniques and tested, comparing the results with DNS. The performance limitations of mode 1 and mode 2 are overcome by using a multi-input controller that uses both deflection modes together. Finally, the controllers are tested in an off-design condition at a higher Reynolds number of 1000.

Robust Power System Stabilizer Design Using Eigenstructure Assignment

This paper presents a design of a power system damping controller using partial right eigenstructure assignment. The eigenstructure assignment technique selects a set of closed-loop eigenvalues along with their right or left eigenvectors. The selection of eigenvectors offers extra flexibility which is exploited in this paper by designing a robust damping controller which provides the required damping under multiple operating conditions. A multi-input controller is used to increase the degrees of freedom available for the design. Remote measurements available from synchronised phasor measurements are also considered. The problem is formulated as a multi-objective nonlinear optimization problem and solved using the nonlinear simplex function in MATLAB. The proposed technique is used to design a robust power system stabilizer for the interconnected New England New York simplified power system model. Four contingencies are selected as additional operating conditions. The designed controller is validated using a nonlinear simulation.

A Self-Tuning Adaptive Controller for 3-D Image-Guided Ultrasound Cancer Therapy

One of the challenges in MRI-controlled hyperthermia cancer treatment for localized tumor is that the tissue properties are dynamic and difficult to measure. Therefore, tuning the optimal gains for a constant gain controller can be challenging. In this paper, a new multi-input single-output adaptive controller strategy is proposed to address these problems. The inputs to the controller block are the frequency, rotation rate, and applied power level of an interstitial applicator, and the output is the boundary temperature during treatment. The time-varying gains of the new controller are updated over time using Lyapunov-based stability analysis. The robustness of the new controller to changes in the parameters of the tissue is investigated and compared to a constant gain controller through simulation studies. Simulations take into account changes in tissue properties and other conditions that may be encountered in a practical clinical situation. Finally, the effectiveness of the proposed controller is validated through an experimental study.

Optical implementation of fuzzy-logic controllers Part I

In recent years fuzzy-logic-based controllers have become the preferred tool for implementing control mechanisms in high-complexity systems. We suggest novel implementations of a basic fuzzy controller. First, we show the principles of fuzzy-logic control and explain the concept behind the optical controller. Next we review a one-dimensional fuzzy-logic-based optoelectronic controller that was suggested in 1994. Finally, we present a novel two-dimensional optical control approach accompanied by computer simulations of an inverted pendulum. The two-dimensional setup is first given for a dual-input controller and then expanded to a multi-input controller.

Multi-dimensional Pokayoke-Stoplight Control system in unmanned manufacturing cells

A multi-dimensional Pokayoke-Stoplight Control (M-PSC) system has been developed that uses an on-line, real-time, and fuzzy-logic-based approach. By using various non-contact or contact sensors, multi-dimensional measurements have been taken on a real-time basis. By processing in a multi-input and single-output fuzzy logic controller, the measurements are interpreted to represent the status of the manufacturing process. The fuzzy logic controller serves as a decision-making device to turn on a stoplight, e.g. green, yellow, or red, not only to indicate the acceptance of the product but also to warn the monitor of the UMC when a change in the process occurs. The fuzzy logic system has been pre-defined based on the statistical process control technique and 100% inspection methodology. This approach enables the M-PSC system to provide on-line, real-time inspection to prevent defects before they occur in a UMC. The performance of the M-PSC system has been evaluated by experimental tests on a CNC lathe. The results demonstrate that the M-PSC system provides a UMC with a “make one, check one, and pass one on” capability.

Temperature control of multizone indoor spaces based on forecast and actual loads

This paper presents the design of a multivariable controller for zone temperature control. A two-zone building with a fan-coil heating system is considered and a multi-input controller is designed. The controller tracks the reference trajectories which are generated based on forecasted outdoor temperature and at the same time regulates the zone temperatures in response to the actual variations in outdoor temperatures. Results showing the closed-loop responses of the system under realistic operating conditions are given.

New results in feedback modal-controller design

The problem of designing a state feedback controller which drives the eigenvalues of a linear multivariable system to prespecified positions is studied. The approach followed is that of transforming the system under control to a phase-variable canonical form prior to the application of the control design procedure. This transformation is possible only when the system is state-controllable which implies that it is also mode-controllable. The single-input design problem is first considered and solved by an elegant utilization of the concept of state similarity transformation. By this transformation one essentially converts the original problem of designing the state feedback modal controller matrix gain F to that of determining the associated similarity transformation T. The multi-input controller design problem is then treated by an extension of the above results which yield the most general state feedback modal controller possible. The state feedback modal controller derived is utilized, and the most gene...