Adaptive Torsional Vibration Control of the Nonlinear Rolling Mill Main Drive System with Performance Constraints and Sensor Errors

Torsional adaptive control of motor drive process in hybrid power system considering disturbance

In the main drive system of a rolling mill, shaft torsional vibration is often generated when a motor and a roll are connected with a flexible shaft. State feedback control can effectively suppress the torsional vibration of the main drive system of a rolling mill. Because of the difficulty of measuring the load speed and the shaft torque, and moreover the sensitivity of the Luenberger observer to the model uncertainties and the noise include in the detected signal, in this paper, we propose an extended state observer (ESO), a new observer, to estimate the unknown states and the load torque disturbance. We propose an ESO and linear quadratic (LQ) based speed controller with an integrator and load torque feedforward compensation for torsional vibration suppression in a two-mass main drive system of a rolling mill. The simulation results show the controller effectively improves the performances of command following, torsional vibration suppression, and robustness to parameter variation. This is the first time that the ESO has been utilized in torsional vibration control of the main drive system of a rolling mill, and its validity and superiority is verified in comparison with the conventional proportional integral (PI) controller and the state feedback controller based on a reduced-order state observer.

For suppressing torsional vibration on main driving system of the rolling mill, the paper studied modal control and control model of torsional vibration. Dynamic disturbance of the rolling mill main driving system were induced by small perturbation from torque fluctuation. Modal control analysis were investigated on include amplitude and phase response on reference change or load change, bode diagrams, and time domain simulations. Torque fluctuation reflects non-steady cyclical or quasi-cyclical characteristics on the torsional vibration system. Control model had been reconstructed from inversion of dynamic topology theory. The result of simulation showed that the established control model for suppressing torsional vibration was effectiveness. Feedback control experiment of nipping and throwing steel on the rolling mill’s main driving system using reaction control tactic was proved it could be easy input and output for controling to suppressing vibration.

In order to solve the problem of torsional vibration instability of the control system for turboshaft engine caused by low-order torsional vibration modal drift under variable rotor speed effectively, an adaptive torsional vibration suppression method based on the least mean square algorithm is proposed and designed. First, based on Lagrange equation and state space method, the structural dynamic model of torque transmission chain system is established, which takes into account fixed and variable gear ratio. It is beneficial to express the dynamic characteristics of torsional vibration in real time, so that the variation laws of low-order torsional vibration modal under variable rotor speed and gear ratio are revealed. Then, an adaptive torsional vibration filter based on least mean square algorithm is proposed and designed combined with the active control objective of helicopter power system. Finally, the effectiveness of adaptive torsional vibration suppression method is validated based on numerical simulation and hardware-in-loop simulation separately. The results show that compared with the conventional constant-coefficient notch filter, the adaptive torsional vibration filter can decrease the peaks of all low-order torsional vibration frequency by more than 50%. It proves better robustness, more remarkable effectiveness and superior adaptive ability of the adaptive torsional vibration suppression method.

The torsional vibration often occurs during the rolling process, which will affect the production equipment. Based on electromagnetic field theory, the air gap magnetic field energy of salient pole synchronous motor was given, and the expression of electromagnetic torque was derived using the energy analysis method. In order to study the electromechanical coupling characteristics of the main drive system in rolling mill, a torsional vibration model with strongly nonlinear terms was established on the basis of mechanical dynamic principle. The periodic solutions of the strongly nonlinear torsional vibration system were obtained using the incremental harmonic balance (IHB) method. When the excitation force amplitude and the electromagnetic stiffness changed, the influence law on the torsional vibration characteristics of electromechanical coupling system under strongly nonlinear conditions was found. The effects of different electrical and mechanical parameters on the system amplitude‐frequency property and vibration displacement characteristics were analyzed. All these research results are significant to structure design, parameter optimization and vibration control for the mill drive system.

Study on torsional vibration characteristics and suppression of electric vehicles with dual-motor drive system

Mechanism analysis and suppression strategy research on permanent magnet synchronous generator wind turbine torsional vibration

Rolling mill drive-trains, driven by AC or DC motors, have historically experienced premature component fatigue failures even when the perceived operating load is well below the design limit. This is often related to low damped torsional vibrations, especially to self-excited vibrations in rolling slippage (especially during threading and tailing out of a rolled piece), overloading the elements of the drive-train. Long transmission shafts make these vibrations become more critical. A regulator aimed at damping the torsional vibrations of the rolling mill drive-train and thus reducing the electric motor speed fluctuations is presented in this paper. The proposed regulator relies on a reduced order state observer able to estimate the shaft torque amplifications due to the working process. The capability of the regulator to damp out torsional vibrations has been verified through simulations on a lumped parameter torsional model of a single-stand rolling mill accounting for torsional deformability of the power-train shafts.

This study investigates torsional vibration characteristics in an aged coastal car ferry propulsion system using theoretical calculations based on the Matrix method alongside experimental measurements. While the measured torsional vibration at the propeller shaft remained within the limits, it was significantly higher than the calculated values, particularly at the 5th harmonic order excited by engine combustion. Negative torque peaks observed during transient clutch engagement caused gear hammering. Structural vibration analysis identified potential gearbox defects, such as wear or misalignment. Multiple torsional vibration calculation models were developed considering various degrees of degradation of the aged rubber blocks and viscous torsional damper. A model assuming that the damping capacity of damper drops to about 1%, corresponding to the specified values at 125 °C, produced results that closely reproduced the measured vibration characteristics. The finding, confirmed by an actual inspection, identifies viscous oil leakage and deterioration of the damper as the primary cause of excessive vibration. Prompt replacement of the viscous oil is recommended to improve torsional vibration behavior.

A mathematical model of the main drive system of rolling mill is developed for the motor armature faults in the main drive system of rolling mill, taking into account the effects of nonlinear damping, friction damping between rolls and external perturbations on the system during operation. The unknown input observer is designed to process perturbations and errors as unknown inputs, and the [Formula: see text] performance index is designed to improve the robustness of the unknown input observer to fault reconfiguration. At the same time, in order to ensure the stability of the main drive system of rolling mill after the occurrence of faults, an active fault-tolerant controller is designed for the main drive system of rolling mill after obtaining the accurate fault reconfiguration value, which realizes the active fault-tolerant control of the main drive system of rolling mill. Through the simulation study on the main drive system of 2030 mm cold rolling mill stand F4, it is shown that the system is restored to the normal state after adding the fault-tolerant controller, and the motor angular speed error and roll angular speed error are 2.12% and 2.43%, respectively. Comparing with the fault-tolerant control method based on fault estimation, the root-mean-square errors of the motor angular speed and roll angular speed estimates of the designed fault-tolerant control method are reduced by 4.24% and 3.28%, respectively. Simulation verifies the effectiveness of the proposed method.

The article describes the thickness control system of the plate rolling mill. A complex flatness control system of the rolling mill as a mechatronic system was developed. Electric and hydraulic control mechanisms of the sheet thickness were considered. The mechanisms control scheme and the signals transmission scheme of the rolling mill were composed. The block diagram of the screw-down mechanism motion control system was developed. The simulation results were compared with the data of electromechanical screw-down mechanism of the Magnitogorsk Steel Works hot plate rolling mill 5000.

In this study, dry fractionation process was proposed in order to obtain protein-enriched sunflower meal fractions. The process includes two-stage grinding using a hammer mill and a roll mill, and fractionation of sunflower meal by sieving. Central composite design (CCD) with four variables on three levels within response surface methodology was applied in order to estimate the influence of grinding parameters (sieve openings diameter of the hammer mill: 2, 4, and 6 mm, roll gap: 0.15, 0.2, and 0.25 mm, feed rate: 0.1, 0.175, and 0.25 kg/cm min, and roll speed: 400, 500, and 600 rpm) on responses (protein content, fraction yield and grinding energy consumption). Sieve openings diameter expressed the highest impact on fraction yield while roll gap expressed the most dominant influence on protein content in the fraction and grinding energy consumption. The highest protein content obtained was 48.06%(dm) with fraction yield of 77.22%. A multi-response optimization procedure was performed and optimal values were: sieve openings diameter of 2 mm, roll gap of 0.25 mm, feed rate of 0.2 kg/cm min, and roll speed of 400 rpm, while predicted values for a desired range of responses were: protein content 45.5%(dm), fraction yield 77.89%, and grinding energy consumption 8.31 Wh/kg.

SummaryIn this article, we investigate the problem of nonlinear modeling and adaptive boundary vibration control with actuator failure for a flexible rotatable manipulator in three‐dimensional space, which is made up of a rotatable base and a flexible manipulator. In order to accurately reflect the characteristics of the distributed parameters, the Hamilton principle is introduced to derive the dynamic model expressed by partial differential equations (PDEs). Based on the model, an innovative boundary control scheme is proposed to eliminate the deflection and vibration simultaneously, and to guarantee that the rotatable base and the flexible manipulator can track the desired angle respectively. The adaptive law is developed to estimate the loss of the actuator. The effectiveness of the designed controller is verified from both theoretical analysis and numerical simulation.

This paper investigates the vibration control of geometrically nonlinear beam with Macro Fiber Composite (MFC) actuators using two different adaptive control algorithms. A complete mathematical modeling is presented in order to find the dynamic equation of motion. Then, a robust adaptive fuzzy control algorithm for controlling the proposed mechanical structure is introduced. This controller includes a fuzzy scheme and a robust controller. Based on sliding mode controller a fuzzy system is introduced to mimic an ideal controller. The robust controller is designed based on compensation of the difference between the fuzzy controller and the ideal controller. The parameters of the fuzzy system and uncertainty bound of the robust controller are adjusted adaptively. The adaptive laws are designed based on the Lyapunov stability theorem to reach the stability of the closed-loop system. Meanwhile, for comparison purposes the presented controller is compared with self tuning Ziegler-Nichols PID controller for both robustness and vibration suppression performance aspects. Effectiveness of these two control strategies is evaluated by numerical simulations. Detailed analysis for the closed-loop system is carried out to evaluate the vibration controlling performance under different output excitation, robustness of the closed-loop system under sudden loading and the effect of initial condition on vibration characteristic.

Accurate tracking controller design for high-speed drives