Mechanical parameter identification of two-mass drive system based on variable forgetting factor recursive least squares method

Chen, Ke; Ai, Wu; Chen, Bing

doi:10.1177/0142331218765614

Cited by 17 publications

(8 citation statements)

References 26 publications

(24 reference statements)

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“…Figure 4 shows a simplified block diagram of the speed control system [41]. Apparently, deriving the elastic torque from electrical parameters will not allow us to find the peak dynamic loads at the eigenfrequencies of the mechanical system (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25). Besides, this method does not provide sufficient accuracy in case of variable frequency drives.…”

Section: Problem Formulationmentioning

confidence: 99%

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Development of an Automatic Elastic Torque Control System Based on a Two-Mass Electric Drive Coordinate Observer

et al. 2021

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Development of control system based on digital twins of physical processes is a promising area of research in the rolling industry. Closed-loop control systems are developed to control the coordinates of two-mass electromechanical systems in order to limit the dynamic loads on the equipment of main rolling lines. These control systems are based on observers (digital shadows) that indirectly detect (reconstruct) the roll speed and the elastic torque of the shaft (spindle) in real time. Notably, observers are required to work fast in order to reconstruct transients attributable to shock (impact) loads. Literature review shows that the known observers, which use complex algorithms to compute coordinates, do not respond fast enough. The paper analyzes the kinematic diagram of Mill 5000, a plate rolling mill. It presents oscillograms that prove that the elastic torque does oscillate as the rolls grip the strip dynamically. The authors hereof have developed an observer that reconstructs the coordinates of the uncontrolled mass (the shaft) and the spindle torque from the parameters of the controlled mass, namely the torque and speed of the motor. The paper further rationalizes an approach that consists of simulating the processes on a model to further directly configure them on the object. The authors analyze the transients of the reconstructed two-mass system coordinates, which are associated with the rolls gripping the strip. The paper compares data against oscillograms recorded on the mill itself. The accuracy is satisfactory. The proposed observer has been used to developed a three-loop automatic speed control system for the uncontrolled mass. Controller configurations are substantiated. The paper shows coordinates obtained by simulation modeling as functions of time. It further presents experiments run on Mill 5000; the conclusions are that the amplitude and oscillations of the elastic torque drop significantly. The paper concludes with recommendations on industrial adoption of the observer and the novel electric drive coordinate control system. Study presented herein substantiates and implements a concept of developing algorithms that solve specific problems and are readily implementable on the existing equipment without need for additional computing devices. The contribution of the paper consists of stating and solving the problem of developing and testing an automatic elastic torque control system for the shaft of a heavy-duty rolling mill. This system has been implemented in the form of algorithms that run in the software of the existing industrial controllers (PLCs). It is simple and performs well. It does not need additional sensors or computers to be implemented, nor does it rely on complex computational algorithms. Such algorithms are based on computational tables that require a priori data on numerous process parameters. In our literature review, we have not come across any industrial implementation of such algorithms on hot-rolling mills.

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Section: Problem Formulationmentioning

confidence: 99%

“…In Russia, it is mainly researched by the Ivanovo State Energy University [7][8][9][10]. The problem is also covered in [11][12][13][14][15]. Dynamic stability improvement and reducing the influence of interference are the problems covered in [16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Development of an Automatic Elastic Torque Control System Based on a Two-Mass Electric Drive Coordinate Observer

et al. 2021

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“…All the more so as the identification of the moment of inertia, the viscous friction coefficient and the load torque and setting their values is very challenging. The DT is an alternative method for representing the two-mass drive system [25].…”

Section: B Digital Twin Description and Implementationmentioning

confidence: 99%

“…The systems are assumed to be two-mass drive systems with a flexible shaft connecting the motor and the (elastic) load. This topic has received great attention from the scientific community, because the identification of mechanical parameters of the two-mass drive systems is not straightforward [25]. To the best of the authors' knowledge, the key point is the design and implementation of the DT for the whole system, including the virtual representation of all mechanical and electrical components including the load, the main nonlinearities (backlash and friction), and the corresponding control system.…”

Section: Introductionmentioning

confidence: 99%

Digital Twin-Based Optimization for Ultraprecision Motion Systems With Backlash and Friction

et al. 2019

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A digital twin-based optimization procedure is presented for an ultraprecision motion system with a flexible shaft connecting the motor to the (elastic) load, which is subject to both backlash and friction. The main contributions of the study are the design of the digital twin and its implementation, assuming a two-mass drive system. The procedure includes the virtual representation of mechanical and electrical components, non-linearities (backlash and friction), and the corresponding control system. A procedure for digital twin-based optimization is also presented, in which the maximum absolute position error is minimized while maintaining accuracy with no significant increase in the control effort. The optimal settings for the controller parameters and for the backlash peak amplitude, the backlash peak time, and the hysteresis amplitude are then determined, in order to guarantee an appropriate dynamic response in the presence of backlash and friction. The surface quality of certain manufactured components, such as hip and knee implants, depends on the smoothness and the accuracy of the real trajectory produced in the cutting process that is strongly influenced by the maximum position error. The simulations and experimental studies are presented using a real platform and two references for trajectory control, and a comparison of four digital twin-based optimization methods. The simulation study and the real-time experiments demonstrate the suitability of the digital twin-based optimization procedure and lay the foundations for the implementation of the proposed method at an industrial level.

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“…Damping ratios and natural frequencies of linear-time-invariant flexible mechanical systems are estimated with least-squares error optimization (Chee et al, 2010). Authors identified moment of inertia, viscous friction coefficient, and load torque of two-mass drive system by combining a Luenberger observer and the variable forgetting factor recursive least-squares method (Ke et al, 2018). Flexible structures such as beams (Abreu et al, 2012; Bu et al, 2003; Saad et al, 2013; Afshari et al, 2014) and cantilever plate (Dong et al, 2006) are studied with Auto-Regressive eXogenous (ARX), Auto-Regressive Moving Average eXogenous (ARMAX), Finite Impulse Response (FIR), and Eigensystem Realization Algorithm (ERA) models to estimate dynamic models.…”

Section: Introductionmentioning

confidence: 99%

Measurement and modeling of a flexible manipulator for vibration control using five-segment S-curve motion

Malgaca

Lök

2021

Transactions of the Institute of Measurement and Control

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User designed manipulators are widely used in industry as a part of automation. The design of lighter robotic arms is required for less energy consumption. Joints, structural features, and payload affect the dynamic behavior of manipulators. Even if the arms have sufficient structural rigidity, joints, or payloads further increase their flexibility. These factors should be considered at the design stage. Flexibility causes vibrations, and these vibrations negatively affect robot repeatability and processing speed. Reducing the vibration levels of flexible manipulators is an attractive issue for engineers and researchers. Accurate estimation of the mathematical model of flexible manipulators increases the success of vibration control. In this paper, the modeling and experiments for vibration control of a single-axis flexible curved manipulator with payload are considered. The experimental system is introduced to collect vibration responses synchronously at the tip of the curved manipulator for angular velocity input. The mathematical model of the manipulator is estimated using the continuous-time system identification (CTSI) method with a black-box model based on the experimental input/output (I/O) signals. A five-segment S-curve motion input based on the modal parameters is designed to suppress residual vibrations. Vibration control is successfully performed for different deceleration times of the designed S-curve motion input. The results showed that the residual vibrations from experiments and predicted models matched well for different cases depending on payload, angular position, and motion time.

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Mechanical parameter identification of two-mass drive system based on variable forgetting factor recursive least squares method

Cited by 17 publications

References 26 publications

Development of an Automatic Elastic Torque Control System Based on a Two-Mass Electric Drive Coordinate Observer

Development of an Automatic Elastic Torque Control System Based on a Two-Mass Electric Drive Coordinate Observer

Digital Twin-Based Optimization for Ultraprecision Motion Systems With Backlash and Friction

Measurement and modeling of a flexible manipulator for vibration control using five-segment S-curve motion

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