Laboratory Implementation of Direct Torque Controller based Speed Loop Pseudo Derivative Feedforward Controller for PMSM Drive

This paper,evaluate the effectiveness of a proposed speed loop pseudo derivative feedforward(PDFF)controller-based direct torque controller(DTC)for a PMSM drive against the performance of existing PI speed controller-based DTC and hysteresis current controller(HCC).The proposed PDFF-based speed regulator effectively reduces oscillation and overshoot associated with rotor angular speed,electromagnetic torque,and stator current.Two case studies,one using forward-to-reverse motoring operation and the other involving reverse-to-forward braking operation,has been validated to show the effectiveness of the proposed control strategy.The proposed controller's superior performance is demonstrated through experimental verification utilizing an FPGA controller for a 1.5 kW PMSM drive laboratory prototype.

Dynamic Feedforward Control of a Novel 3-PSP 3-DOF Parallel Manipulator

Parallel manipulators with less than six degrees of freedom （DOF） have been increasingly used in high-speed hybrid machine tools. The structural features of parallel manipulators are dynamic, a characteristic that is particularly significant when these manipulators are used in high-speed machine tools. However, normal kinematic control method cannot satisfy the requirements of the control system. Many researchers use model-based dynamic control methods, such as the dynamic feedforward control method. However, these methods are rarely used in hybrid machine tools because of the complex dynamic model of the parallel manipulator. In order to study the dynamic control method of parallel manipulators, the dynamic feedforward control method is used in the dynamic control system of a 3-PSP （prismatic-spherical-prismatic） 3-DOF spatial parallel manipulator used as a spindle head in a high-speed hybrid machine tool. Using kinematic analysis as basis and the Newton-Euler method, we derive the dynamic model of the parallel manipulator. Furthermore, a model-based dynamic feedforward control system consisting of both kinematic control and dynamic control subsystems is established. The dynamic control subsystem consists of two modules. One is used to eliminate the influence of the dynamic characteristics of high-speed movement, and the other is used to eliminate the dynamic disturbances in the milling process. Finally, the simulation model of the dynamic feedforward control system of the 3-PSP parallel manipulator is constructed in Matlab/Simulink. The simulations of the control system eliminating the influence of the dynamic characteristics and dynamic disturbances are conducted. A comparative study between the simulations and the normal kinematic control method is also presented.The simulations prove that the dynamic feedforward control method effectively eliminates the influence of the dynamic disturbances and dynamic characteristics of the parallel manipulator on high-speed machine tools, and significantly improves the trajectory accuracy. This is the first attempt to introduce the dynamic feedfordward control method into the 3-PSP spatial parallel manipulator whose dynamic model is complex and provides a study basis for the real-time dynamic control of the high-speed hybrid machine tools.

The application of feedforward control in the nursing emergency management of COVID-19

Objective:To explore the application of feedforward control in the nursing emergency management of COVID-19.Methods:The feedforward control theory was applied to the emergency management of COVID-19 nursing,including grasping the latest epidemic information,preparing for the early stage,formulating nursing workflow,implementing flexible management,standardizing isolation and protection measures,unifying nursing document record format,and implementing humanistic care.Results:During the period of support to Wuhan,the nursing work in the isolated area was orderly,the nursing staff's job satisfaction was high,no nursing errors and hospital infections occurred.Conclusion:Efficient feedforward control in the nursing emergency management that could avoid work blindness to a certain extent and play a guiding role in maintaining the normal operation of treatment and nursing work and protecting the safety of patients and medical staff in the ward during the epidemic period of COVID-19.

FEEDFORWARD CONTROL STRATEGIES FOR TRACKING PERFORMANCE IN MACHINE AXES

Three feedforward (FFD) control techniques for position-servo machine axesare compared. All three FFD controllers are used with two different PID feedback (FBK) controllers.The two different FBK controllers have two different closed-loop bandwidths. They are demonstratedusing experimental data from a linear motor test system and from simulations. Laboratory resultsusing the linear motor hardware demonstrate that the velocity & acceleration (V&A) FFD controllerimproves tracking in all case considered, while the other two FFD controllers actually degradeperformance in many cases. Through simulation this degradation is attributed to extreme sensitivityto round off errors. This sensitivity is the result of a complex controller that is implementedoutside of the feedback loop.

A Feedforward Controller to Regulate the Chemical Composition of Molten Steel in a Continuous Casting Tundish

A feedforward controller for the automatic regulation of chemical composition of molten steel in the tundish of a continuous casting machine is proposed in this work. The flow of molten steel inside the tundish is modeled as a distributed parameter system, and the resulting partial differential equation is transformed into a set of ordinary differential equations by means of the finite differences technique. From the above set and using a proper boundary condition, a feedforward control law is synthesized. No experimental tests are reported, however, the dynamic performance of the controller is illustrated by means of numerical simulations.

Feedback and Feedforward Optimal Control for Offshore Jacket Platforms

The optimal control is investigated for linear systems affected by external harmonic disturbance and applied to vibration control systems of offshore steel jacket platforms. The wave-induced force is the dominant load that offshore structures are subjected to, and it can be taken as harmonic excitation for the system. The linearized Morison equation is employed to estimate the wave loading. The main result concerns the existence and design of a realizable optimal regulator, which is proposed to damp the forced oscillation in an optimal fashion. For demonstration of the effectiveness of the control scheme, the platform performance is investigated for different wave states. The simulations are based on the tuned mass damper and the active mass damper control devices. It is demonstrated that the control scheme is useful in reducing the displacement response of jacket-type offshore platforms.

An iterative learning method for realizing accurate dynamic feedforward control of an industrial hybrid robot

Feedforward control based on an accurate dynamic model is an effective approach to reduce the dynamic effect of the robot and improve its performance. However, due to the complicated work environment with considerable uncertainty, it is difficult to obtain a high-precision dynamic model of the robot, which severely deteriorates the achievable control performance. This paper proposes an iterative learning method to accurately design the industrial feedforward controller and compensate for the external uncertain dynamic load of the robot. Based on a standard dynamic model, a complete linear feedforward controller is presented.An iterative design strategy is given to iteratively update the feedforward controller by combining the Moore-Penrose Inverse and the PID learning rate. Experiments are carried out on a 5-DOF industrial hybrid robot to validate the effectiveness of the proposed iterative learning method. The experiment results illustrate that the industrial feedforward controller can rapidly converge to the optimal controller and significantly improve the servo performance by using the proposed method. This paper provides an effective method for applying iterative learning control to an unopened industrial control system. It is very useful for the practical control of hybrid robots in industrial field.

Feedforward control for nitrogen removal in a pilot-scale anaerobic-anoxic-oxic plant for municipal wastewater treatment

To improve the efficiency of nitrogen removalwith lower energy consumption,the study of feedforwardcontrol was carried out on a pilot-scale anaerobic-anoxicoxic(AAO)plant for the treatment of municipal wastewater.The effluent qualities of the pilot plant underdifferent control strategies were investigated.The resultsindicated that the change of external recycle was not asuitable approach to regulate the sludge concentration ofplug-flow reactors;adjusting the aeration valve anddissolved oxygen set-point according to ammonia loadcould overcome the impact of influent fluctuation;and thedenitrification potential could be estimated based on thetransit time of anoxic zone and the relative content ofcarbon resource entering the anoxic zone.Simple feedforwardcontrol strategies for aeration and internal recyclewere subsequently proposed and validated.The nitrogenremoval was successfully improved in the pilot plant.Theeffluent total nitrogen had decreased by 29.9%and wassteadily controlled below 15 mg·L^(-1).Furthermore,approximately 38%of the energy for aeration had beensaved.

Feedforward Control for Wind Turbine Load Reduction with Pseudo-LIDAR Measurement

A gain-scheduled feedforward controller, based on pseudo-LIDAR （light detection and ranging） wind speed measurement, is designed to augment the baseline feedback controller for wind turbine＇s load reduction in above rated operation. The pseudo-LIDAR measurement data are generated from a commercial software- Bladed using a designed sampling strategy. The nonlinear wind turbine model has been simplified and linearised at a set of equilibrium operating points. The feedforward controller is firstly developed based on a linearised model at an above rated wind speed, and then expanded to the full above rated operational envelope by employing gain scheduling strategy. The combined feedforward and baseline feedback control is simulated on a 5MW industrial wind turbine model. Simulation studies demonstrate that the proposed control strategy can improve the rotor and tower load reduction performance for large wind turbines.

Feedforward and feedback optimal control for linear time-varying systems with persistent disturbances

The optimal control problem for linear time-varying systems affected by external persistent disturbances with known dynamic characteristics but unknown initial conditions is consider and a design procedure of a feedforward and feedbaek optimal controller is presented. The condition of existence and uniqueness of the control law is given. The disturbanee observer is proposed to make the feedforward control law realizable physically. Simulation results demonstrate that the feedforward and feedbaek optimal control law is more effective and robust than the elassical state feedbaek control law with respect to external disturbanees.

Feedforward Control of a 3-D Physiological Articulatory Model for Vowel Production

A three-dimensional （3-D） physiological articulatory model was developed to account for the biomechanical properties of the speech organs in speech production. Control of the model to investigate the mechanism of speech production requires an efficient control module to estimate muscle activation patterns, which is used to manipulate the 3-D physiological articulatory model, according to the desired articulatory posture. For this purpose, a feedforward control strategy was developed by mapping the articulatory target to the corresponding muscle activation pattern via the intrinsic representation of vowel articulation. In this process, the articulatory postures are first mapped to the corresponding intrinsic representations; then, the articulatory postures are clustered in the intrinsic representations space and a nonlinear function is approximated for each cluster to map the intrinsic representation of vowel articulation to the muscle activation pattern by using general regression neural networks （GRNN）. The results show that the feedforward control module is able to manipulate the 3-D physiological articulatory model for vowel production with high accuracy both acoustically and articulatorily.

Quantum state protection from finite-temperature thermal noise with application to controlled quantum teleportation

We propose a quantum state protection scheme via quantum feedforward control combined with environment-assisted measurement to protect arbitrary unknown initial states from the finite-temperature thermal noise(FTTN).The main strategy is to transfer the quantum system to a noise-robust state by weak measurement and feedforward control before the noise channel.Then we apply the environment-assisted measurement on the noise channel to select our desired damped states that are invertible to the initial state.After the noise channel,the reversal operations are applied to restore the initial state.We consider the protection of a single-qubit system,derive the analytical expressions of the success probability and the fidelity,and analyze the influence of key parameters on the performance of the proposed scheme.Unlike previous studies,there is no trade-off between the fidelity and the success probability in the proposed scheme;hence one could maximize them separately.Simulation results show that the proposed scheme can greatly improve the fidelity of the quantum state with a certain success probability.Moreover,the proposed scheme is successfully applied to improving the fidelity of controlled quantum teleportation through two independent FTTN channels from the perspective of protecting the shared entanglement.

Feedforward and Feedback Optimal Control for Linear Systems with Sinusoidal Disturbances

The linear systems affected by additive external sinusoidal disturbances is studied. The problem is to damp this forced oscillation in an optimal fashion. The main result of this paper is a new design approach is proposed of realizable feedforward and feedback optimal control law for a linear time invariant system with sinusoidal disturbances. The algorithm of solving the optimal control law is given. It is shown that the control law is easily realized and is robust with respect to errors produced by the external sinusoidal disturbances through simulation results.

A New Feedback-feedforward Configuration for the Iterative Learning Control of a Class of Discrete-time Systems

这份报纸为反复的学习控制(ILC ) 论述一种新反馈前馈控制配置与反馈设计，它由反馈和一个前馈控制部件组成。反馈积分控制器稳定系统，并且在操作，和前馈控制 ILC 期间起主导的作用补偿可重复的非线性 / 未知的变化时间的动力学和骚乱，从而提高性能独自由反馈控制完成了。作为这控制策略的最有利的点，没有作努力到前馈控制 / 反馈获得的 reconfigurate 或重新调律，前馈控制 ILC 和反馈控制能独立地或联合工作。与严密分析，建议学习控制计划沿着重复轴保证 asymptotic 得到集中。

Feedforward Variable Structural Proportional-Integral-Derivative for Temperature Control of Polymerase Chain Reaction

To track the rapidly changing temperature profiles of thermal cycling of polymerase chain reaction (PCR) accurately, an innovative feedforward variable structural proportional-integral-derivative (FVSPID) control- ler was developed. Based on the step response test data of the heat block, a reduced first order model was estab- lished at different operating points. Based on the reduced model, the FVSPID controller combined a feedforward path with the variable structural proportional-integral-derivative (PID) control. The modified feedforward action provided directly the optimal predictive power for the desired setpoint to speed up the dynamic response. To coop- erate with the feedforward action, a variable structural PID was applied, where the P mode was used in the case of the largest errors to speed up response, whereas the PD mode was used in the case of larger errors to suppress over- shoot, and finally the PID mode was applied for small error conditions to eliminate the steady state offset. Experi- mental results illustrated that compared to the conventional PID controller, the FVSPID controller can not only re- duce the time taken to complete a standard PCR protocol, but also improve the accuracy of gene amplification.

Adaptive Zero Phase Error Feedforward Method for Robotic Force Control

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Application of Feedforward and Feedback Control Strategy for Wire Rod Hot Rolling Line

The feedforward and feedback control strategy of water flowrate based on the analysis of thermal process in water cooling box was proposed, and the control strategy was applied to wire rod hot rolling at Baosteel Co. The operation has proved that the strategy can control water flowrate in the cooling water box reasonably to ensure the temperature requirement of the wire discharged from the cooling water box.

Feedforward and feedback optimal control for linear time-varying systems with persistent disturbances

The optimal control problem was studied for linear time-varying systems,which was affected by external persistent disturbances with known dynamic characteristics but unknown initial conditions. To damp the effect of disturbances in an optimal fashion,we obtained a new feedforward and feedback optimal control law and gave the control algorithm by solving a Riccati differential equation and a matrix differential equation. Simulation results showed that the achieved optimal control law was realizable,efficient and robust to reject the external disturbances.

Multiple models adaptive feedforward decoupling controller

When the parameters of the system change abruptly, a new multivariable adaptive feedforward decoupling controller using multiple models is presented to improve the transient response. The system models are composed of multiple fixed models, one free-running adaptive model and one re-initialized adaptive model. The fixed models are used to provide initial control to the process. The re-initialized adaptive model can be reinitialized as the selected model to improve the adaptation speed. The free-running adaptive controller is added to guarantee the overall system stability. At each instant, the best system model is selected according to the switching index and the corresponding controller is designed. During the controller design, the interaction is viewed as the measurable disturbance and eliminated by the choice of the weighting polynomial matrix. It not only eliminates the steady-state error but also decouples the system dynamically. The gtobel convergence is obtained and several simulation examples are presented to illustrate the effectiveness of the proposed controller.