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This paper explores the features of numerical simulation used to analyze the dynamic behaviour of drives controlled by pulse-width modulators. Modern motor control systems commonly employ pulse-width modulation. Effective numerical modelling of such systems presents unique challenges because the models employed are continuous-event and have hybrid behaviour due to the presence of nonlinear links with discontinuities of the first kind. Therefore, it is essential to have special integration methods with variable steps, which should be factored in when developing the model. This paper shows how these problems are solved when modelling an electric drive with a DC motor using the SimInTech software. [ABSTRACT FROM AUTHOR]

This paper deals with the tuning of the parameters of a fractional-order PI controller for the speed control of an electric servo drive in which the torque is set by a torque generator. The controller parameters are tuned using the multiple dominant pole method (MDPM), while the fractional order integrator is approximated by the Oustaloup method. The input parameters required for tuning the controller using MDPM are calculated using the optimization algorithm presented in this paper. This algorithm selects the optimal parameters from a set of points in three-dimensional space, based on the symmetry around a central point. The controller tuning is performed for the normalized control loop model. The obtained optimized normalized fractional order PI controller can then be applied to a real servo drive with specific parameters. The proposed tuning was also verified experimentally, comparing the obtained closed-loop responses with those of the integer-order PI controller. Both simulation and experimental results showed a significant reduction in the integral of the absolute error at the disturbance step compared to a control loop using an integer-order PI controller. This results in a faster output response to load torque steps and a smaller control error in a real servo drive. [ABSTRACT FROM AUTHOR]

. This work is devoted to the development of control systems for a tracking pneumatic actuator, taking into account the current position of the working body of the actuator and the amount of friction in the friction pairs of the actuator. Implementing the positioning of a pneumatic actuator is a complex technical task, but at the same time extremely relevant, since industrial systems of modern production require the performance of technological operations not only with high speed but also with high accuracy of positioning the working body of the actuator. The paper also considers control systems for pneumatic actuators based on the position of the working body, taking into account the nonlinearity of motion caused by friction forces in the pneumatic actuator. Friction in the contact pairs of pneumatic actuators adversely affects the operation of the actuators, especially taking into account the dependence of friction on ambient temperature, the surface condition of the contact pairs, the availability and quality of lubricants, etc. The study demonstrates existing control systems and implemented static and dynamic models of friction compensation and the impact of such models on the accuracy and controllability of systems with different types of regulators and implementation schemes, including proportional distributors with analog control and highspeed direct-acting distributors. The paper analyzes positioning systems with the ability to regulate the inlet pressure and the impact of such system solutions on the system rigidity and its performance. The paper formulates a goal for further research and identifies a list of tasks necessary to achieve the goal set in the paper. The paper also presents a design solution for a test bench with the ability to implement adaptive control of the actuator force depending on changes in the operating parameters of the technological operation and changes in the parameters of the pneumatic system as a whole. [ABSTRACT FROM AUTHOR]

Dimensional and profile measurements of deep-hole parts are key processes both in manufacturing and product lifecycle management. Due to the particularity of the space conditions of deep-hole parts, the existing measurement instruments and methods exhibit some limitations. Based on the multi-axis, highly precise servo drive system, a novel measuring device is developed. The laser displacement sensors are fed by the flux-switching permanent magnet linear motor, and the part is rotated by the servo motor. On this basis, the assessment methods of roundness, straightness, and cylindricity are proposed by employing the least square method (LSM). Additionally, considering the axial center deviation between the sensors and the part, the rotating center coordinate is optimized by the gradient descent algorithm (GDM). Then, the measurement system is constructed and the experiment study is conducted. The results indicate favorable evaluation error of the LSM fitting and GDM iteration. Compared with the coordinate measuring machine (CMM), the measured results show good consistency. In the error analysis, the angle positioning error of measured point is less than 0.01°, and the axial positioning error is less than 0.05 mm. The proposed system and assessment method are regarded as a feasible and promising solution for deep-hole part measurements. [ABSTRACT FROM AUTHOR]

This paper derives an advanced multi-loop speed feedback system equipped with model-free pole-zero cancellation (PZC) filters for the position and current measurements of servo drives. The proposed feedback system does not necessitate an exact system model, and it renders the transfer function of each loop in a first-order low-pass filter form by involving active damping terms. Furthermore, the PZC filters output the desired speed and current information for each of the loops along the first-order convergent system, independent of the system model. An experimental platform involving a 500 W brushless DC motor, with a digital signal processor as a controller, validates the practical improvement of the proposed feedback system. [ABSTRACT FROM AUTHOR]

The paper describes the process of designing the cutting tool feed drive of a special metalworking machine, which due to the circuit solution and automatic control system will increase the productivity of processing one cell of wafer background on sheet material up to 10–15 seconds. On the basis of the analysis of the technology of milling of a given regular pattern of wafer background and peculiarities of the equipment operation it proposed to replace the traditional ball bearing gear in the cutting tool feed drive with a flat combined crank-slide mechanism. Geometrical parameters of the lever transmission mechanism calculated in accordance with the known dimensions of the regular cell pattern and the recommended value of the angle of motion transmission. The analysis of kinematic and power characteristics of the lever mechanism allowed to justify the technical characteristics of the electric motor. In order to realize the required trapezoidal law of the output link speed change, the inverse problem of kinematics solved, numerical values of the instantaneous angular velocity of the input crank and pulse control signals to the servomotor obtained.

Current drive control systems tend to push control loops to the limits of their performance. One of the ways of doing so is to use advanced optimization algorithms, usually related to model-based off-line calculations, such as genetic algorithms, the particle swarmoptimisation or the others. There is, however, a simpler way, namely to use predictive control formalism and by formulation of a simple linear programming problem which is easy to solve using powerful solvers, without excessive computational burden, what is a reliable solution, as whenever the optimization problem has a feasible solution, a global minimizer can be efficiently found. This approach has been deployed for a servo drive system operated by a real-time sampled-data controller, verified between model-in-the-loop and hardwarein- the-loop configurations, for a range of prediction horizons, as an attractive alternative to classical quadratic programming-related formulation of predictive control task.

This study designs an advanced single-loop output feedback system for speed servo drive applications, in which a simple proportional–integral–integral (PII) controller equipped with nonlinear feedback and feed-forward gains is formed. The resultant feedback system shows the desired critically damped performance for wide-operating regions by actively handling the system parameter and load uncertainties. There are three contributions: first, the third-order observer estimates, independent from the system model, where the speed and acceleration are obtained using the position measurement with the order reduction property; second, the observer-based PII controller is compensated by active damping with a nonlinearly structured feedback and feed-forward gains; and, third, a guarantee is achieved on the desired critically damped performance through a closed-loop analysis. A hardware testbed that adopts a 500 W brushless DC motor is used to experimentally demonstrate performance improvements over certain constant torque regions under various scenarios. [ABSTRACT FROM AUTHOR]

The characteristics of the electric servo drives in industrial robots used in machining complex surfaces are analyzed. Special corrective devices that improve the robot's precision in reproducing the displacement reduce the machining errors due to tool kinematics. [ABSTRACT FROM AUTHOR]

Current drive control systems tend to push control loops to the limits of their performance. One of the ways of doing so is to use advanced optimization algorithms, usually related to model-based off-line calculations, such as genetic algorithms, the particle swarmoptimisation or the others. There is, however, a simpler way, namely to use predictive control formalism and by formulation of a simple linear programming problem which is easy to solve using powerful solvers, without excessive computational burden, what is a reliable solution, as whenever the optimization problem has a feasible solution, a global minimizer can be efficiently found. This approach has been deployed for a servo drive system operated by a real-time sampled-data controller, verified between model-in-the-loop and hardwarein-the-loop configurations, for a range of prediction horizons, as an attractive alternative to classical quadratic programming-related formulation of predictive control task. [ABSTRACT FROM AUTHOR]

RELEVANCE. Servo drives operate with a law of change of the setting action unknown in advance and provide reproduction of this law by the output coordinate. Servo drives find application in robotic and mechatronic systems, machine tools, systems of automatic control and remote transmission of information, radar stations, guidance units, etc. The operation of servodrives often proceeds in conditions of instability parameters and characteristics elements of the electric drive. Corrective devices synthesized by classical methods of automatic control theory cannot cope with providing the specified accuracy of reproduction of the input signal and the required quality of transients. THE PURPOSE. In this regard, an important and urgent task is the synthesis of an active correction system with a non-stationary controller that provides the required quality and accuracy of the control process due to the coefficient self-tuning algorithm. METHODS. When solving this problem, methods for identifying parameters based on the gradient algorithm and numerical integration of the object of study dynamics equations, implemented by means of the MatLab software environment, were used. RESULTS. The paper solves the problem of synthesizing the self-tuning algorithm for the coefficients of the servo drive corrective device based on the identification approach. The parameters are identified by a searchless gradient algorithm while minimizing the discrepancy between the object of study and its inverse model, as well as restoring the coefficients of differential equations using integration and the corresponding computational procedures. An servo drive with negative position feedback is tuned to the modular optimum with a proportional controller whose coefficients are completely determined by the parameters to be identified. The self-tuning algorithm consists in calculating the correction factor of the non-stationary P-controller and forming a multiplicative channel of the active correction closed loop. CONCLUSION. The simulation of the electric drive in the MatLab software environment showed high accuracy and quickness of the process identifying parameters in a wide range of their change. When forming an active correction contour, a necessary requirement is to distinguish between the identification cycle and the self-tuning cycle. This makes it possible to avoid singular perturbations and reduce resonant facts during the operation of a parametrically invariant electric drive. The developed method of active correction with a priori known and unchanged structure of the object model of study makes it possible to maintain the required accuracy and quality of the operation of the electric drive under conditions of parametric disturbances with permissible deviations of accuracy and quality indicators. Implementation of the method does not require additional equipment, organization of special test signals, significant computational costs. The method of synthesizing a parametrically invariant electric drive can be used to develop robust control systems for non-stationary objects, including when the hypothesis of quasi-stationarity is not fulfilled.

In this paper, a new solution for an electro-hydraulic servo drive is proposed, which consists of two electro-hydraulic servo drives: one with a hydraulic cylinder and one with a hydraulic rotary motor. In the proposed drive, the linear actuator is attached to a horizontal base and the hydraulic motor is mounted on the actuator piston rod. Thus, the output signal of the drive is the lifting and lowering of the element suspended on the rope. The paper describes the structure, kinematics, dynamics, and control of a novel electro-hydraulic servo drive. A servo valve and a proportional valve are used to control the flow of the hydraulic cylinder and the hydraulic motor. Special attention is paid to the construction of two actuators in one drive unit. The controller is based on the PLC controller. The measuring system uses laser displacement sensors and an encoder. The results of laboratory investigations are discussed in the paper. The proposed drive contains all of the characteristics of a mechatronic device. The main contribution of this study is the proposal of the controller architecture and the algorithm to control the speed and position when lifting or lowering loads. [ABSTRACT FROM AUTHOR]

The mechanical transmission employed inside the computer numerical control (CNC) machine electromechanical system usually has an inherent backlash. As a position-controlled system is commonly used for the electromechanical system, the backlash limits the performance of the motion control system due to its nonlinearity and discontinuity. This paper proposes an effective method to adaptively detect and compensate for the backlash effect in real time, in which the end-effect load position of the CNC machine is estimated and controlled by the position-controlled servo system, in order to eliminate the influence of backlash on the contour path performance. The simulation results obtained from the model of a realistic CNC machine show the successful elimination of the error between the reference and the end-effector position and a significant improvement in the control system performance. [ABSTRACT FROM AUTHOR]

This study designs an advanced single-loop output feedback system for speed servo drive applications, in which a simple proportional–integral–integral (PII) controller equipped with nonlinear feedback and feed-forward gains is formed. The resultant feedback system shows the desired critically damped performance for wide-operating regions by actively handling the system parameter and load uncertainties. There are three contributions: first, the third-order observer estimates, independent from the system model, where the speed and acceleration are obtained using the position measurement with the order reduction property; second, the observer-based PII controller is compensated by active damping with a nonlinearly structured feedback and feed-forward gains; and, third, a guarantee is achieved on the desired critically damped performance through a closed-loop analysis. A hardware testbed that adopts a 500 W brushless DC motor is used to experimentally demonstrate performance improvements over certain constant torque regions under various scenarios.

In this paper, a new solution for an electro-hydraulic servo drive is proposed, which consists of two electro-hydraulic servo drives: one with a hydraulic cylinder and one with a hydraulic rotary motor. In the proposed drive, the linear actuator is attached to a horizontal base and the hydraulic motor is mounted on the actuator piston rod. Thus, the output signal of the drive is the lifting and lowering of the element suspended on the rope. The paper describes the structure, kinematics, dynamics, and control of a novel electro-hydraulic servo drive. A servo valve and a proportional valve are used to control the flow of the hydraulic cylinder and the hydraulic motor. Special attention is paid to the construction of two actuators in one drive unit. The controller is based on the PLC controller. The measuring system uses laser displacement sensors and an encoder. The results of laboratory investigations are discussed in the paper. The proposed drive contains all of the characteristics of a mechatronic device. The main contribution of this study is the proposal of the controller architecture and the algorithm to control the speed and position when lifting or lowering loads.

This paper presents the issues of increasing the reliability of laser installation coordinate systems as a part of numerically controlled machine tools. Based on GOST 27803-91, "Adjustable Electric Drives for Metalworking Equipment and Industrial Robots. Technical Requirements," a theoretical assessment of the performance of a controlled electric drive with increased reliability indicators was performed. Such a drive was a part of the coordinate system of a laser installation. Here, a calculation method for the parameters of the laser tool position controller and a generalized mathematical model of the electromechanical circuit of the laser installation are presented. The kinematic scheme is based on a brushless direct current motor and ball screw assembly. The simulation results comply with the requirements of clause 2.5.7 of GOST 27803-91 and may be useful for developers of information measurement and control systems for laser installations. [ABSTRACT FROM AUTHOR]

In the new advanced drive schemes, identification and modeling of the load complex characteristics can play an important role to predict the dynamic performance of the proposed control strategy. The novelty of this paper consists in the classification of the different types of the nonlinear loads which the electrical drive systems may encounter. In this study, nonlinear components of mechanical loads are divided into two groups. The first type includes nonlinear phenomenon caused by the nature of load which is predictable and identifiable. Another type of loads nonlinear characteristic happens due to the occurrence of a mechanical fault in motor, coupling or load parts. Generally, this type of non-intended nonlinear effect is not predictable and often occurs in the installation and operation stage of the drive system utilization. In this paper, the performance of an induction servo drive system has been simulated under the influence of different types of non-linear industrial loads. [ABSTRACT FROM AUTHOR]

The mechanical transmission employed inside the computer numerical control (CNC) machine electromechanical system usually has an inherent backlash. As a position-controlled system is commonly used for the electromechanical system, the backlash limits the performance of the motion control system due to its nonlinearity and discontinuity. This paper proposes an effective method to adaptively detect and compensate for the backlash effect in real time, in which the end-effect load position of the CNC machine is estimated and controlled by the position-controlled servo system, in order to eliminate the influence of backlash on the contour path performance. The simulation results obtained from the model of a realistic CNC machine show the successful elimination of the error between the reference and the end-effector position and a significant improvement in the control system performance.

Most existing methods rely on the torque information of a servo drive to predict the tracking error caused by the friction force (friction error), but the torque information is not available in certain systems. This paper proposes a position-based modeling method for the friction error. Two examples are given to verify the practicality of the proposed friction error model on the systems when torque information is not available. The experimental results show that the proposed method can predict the friction error accurately and the proposed online parameter identification method exhibits better performance. The proposed position-based friction error model can also be easily applied to commercial CNC systems because only the position information is required.

This article proposes an extended state observer to broaden the stability range of conventional deadbeat controller. The proposed observer is constructed through the model of permanent magnet synchronous machine (PMSM) which considers the parameters mismatch and unmodeled nonlinear elements. For the high bandwidth of current loop, the closed-loop stability is not ensured through the stability of observer. Therefore, the effect on the closed-loop performance which is caused by the observer is analyzed through the closed-loop transfer function and proved that the deadbeat performance can be kept when the parameters are precise. Furthermore, the system robustness performance is improved through adjusting the observer gain properly when parameters mismatch exists. To ensure the closed-loop stability, H∞ norm of the transfer function is chosen as an index to determine the two gain factors of observer. The effectiveness of the proposed algorithm is verified by Simulation and experimental results. [ABSTRACT FROM AUTHOR]

For interruption operations at higher voltage levels sulfur hexafluoride (SF6) is the dominating insulation and interruption medium. In medium to high voltage levels vacuum has advantages compared to SF6. In order to expand the operation voltage levels of vacuum circuit breakers (VCB), two approaches are possible. The first is the enlargement of the single contact gap and second is the series arrangement. In both cases the Time–Distance-Curve of the contact travel is one factor that influences the interruption performance of VCBs. The usage of a single gap for higher voltage levels requires an increased contact distance. In dependence of different interruption operations, like short circuit or capacitive interruption, a controlled Time–Distance-Curve could be useful. For experimental investigations a vacuum single break test setup using a brushless servo motor with a frequency converter is built. The electrical control of the drive enables parameter variations of the Time–Distance-Curve. The velocity, acceleration, deceleration, and final contact gap can be adjusted as required for testing and later in field application. For fine control a mechanical simulation considering the regulation loop between frequency converter and drive as well as the mechanical components is employed. Finally, tests of the setup for interruption operations are presented. [ABSTRACT FROM AUTHOR]

This paper presents an intelligent permanent magnet synchronous motor-based servo drive system used in automated piano tuning applications. The permanent magnet synchronous motor-based drives are able to improve the accuracy of the piano tuning process in comparison with the traditional direct-current motor-based and step motor-based servo drives. To explain the techniques, firstly, the structure and principles of the automated piano tuning devices with a surface-mounted permanent magnet synchronous motor-based drive system integrated are introduced, illustrating that it is feasible to implement the proposed piano tuning strategy. Secondly, the piano tuning devices have two functions: low-speed rotation and position holding. To ensure that the surface-mounted permanent magnet synchronous motor can rotate stably over the low-speed range with strong anti-interference capacity, a double closed-loop speed-regulation-based control scheme is employed. And to ensure high position control performance, a fuzzy-adaptive triple closed-loop position-regulation-based control scheme is employed. It terms of the control schemes, it deserves to be mentioned that main contributions include, firstly, the parameters of the proportional integral controllers in the double closed-loop speed-regulation structure is tuned relying on both stability and bandwidth analyses. Then, a fuzzy-adaptive proportional integral controller is specially-designed for the triple closed-loop position-regulation to adapt to the piano tuning applications. Simulation is conducted on a 20 rpm three-phase permanent magnet synchronous motor servo drive-based piano tuning system to validate the proposed piano tuning method and to verify the proposed control techniques.

In this article we would like to present cruise control realization. This cruise control is presented as mechanical device for vehicle speed maintenance and has been proposed as a low cost solution. Principle of function in mechanical cruise control is based on a position control of throttle. For the right action of mechanical cruise control it was need to solve some particular tasks related with speed sensing, construct of device for control of throttle position and design of control system of whole mechanical cruise control. Information about car velocity we have gained using Hall sensor attached on a magnetic ring of car tachometer. For control of the throttle was used a small servo drive and as the control unit was used Arduino. The designed solution of mechanical cruise control have been realized for car Škoda Felicia.

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Copyright of China Petroleum Machinery is the property of China Petroleum Machinery Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As universal servos are economical, they are chosen for most of the industrial applications. However, tuning them accurately poses some challenges. Accurate electrical and mechanical parameters are essential for a model-based high-performance servo controller design. In motion control, the variation of inertia is much more significant than that of other parameters. Thus, inertia identification is a key to effective online controller parameter self-tuning, but most conventional inertia-identification methods cannot be well applied in some complicated situations, such as those caused by irregularly and slowly varying speed. Additionally, the traditional control parameter tuning theory displays a deep understanding of the relationship between controller gain and inertia, but lacks an analysis of the maximum bandwidth of the system. In this paper, based on a widely accepted structure that is composed of inertia identification and online controller self-tuning, several simple but useful modifications are proposed. First, to reduce the noise from an encoder quantization error and thus to improve the accuracy of inertia identification, a motor acceleration calculation method featuring an inconstant period is proposed. Then, the scope of the application is extended to make it suitable for position control by redesigning the inertia updating time of the conventional method. In addition, to guarantee the stability of servo systems, the upper constraint of the expected maximum system bandwidth is derived by taking the controller saturation nonlinearity and hardware capacity into consideration. Finally, a modified moderate systematic online servo controller parameter self-tuning method via variable-period inertia identification is presented. The validity, effectiveness, and advantages of proposed strategies are verified by several experimental results. [ABSTRACT FROM AUTHOR]

In order to improve the movement performance of the intelligent car, this thesis design a system of movement control based on self-adaptive non-linear algorithm. This system consists of hardware system and software system. The hardware system consists of elastic suspension and servomechanisms, and the software system is mainly based on self-adaptive control algorithm of the servo drive to realize the motion control of the robot by software programming. In order to test the reliability and the stability of the system motion control, the author respectively carried out the MATLAB simulation experiment and the motor speed test experiment on the system. The experimental results show that the system is highly reliable and stable, and can be widely used as a research and development platform. [ABSTRACT FROM AUTHOR]

The elastic torsional deformation of the transmission parts in the precision transmission system will lead to the mechanical resonance,it has a great impact on the dynamic performance and even lead to the instability and failure of precision transmission components. The precision AC servo drive system with high precision and small teeth difference reducer is built,and the dynamics model of the precision transmission system is established. Due to the problems of multiple parameters and complicated calculations,a multi-parameter sensitivity analysis method is introduced that is based on rotational inertia,stiffness coefficient,transmission ratio and transmission error. A theoretical reference for the design of precision transmission system can be provided by this method.

Taking into account the operational principle of forepoling equipment,and as the target to improving support efficiency and reducing the disturbance on the roof in the process of supporting,a kind of speed and pressure composition control method was presented.The control method adopts the constant pump driven directly by servo motor to replace the traditional electro-hydraulic proportional valve,and the variable structure algorithm based on the fuzzy sliding mode was used as control strategy.Theoretical analysis and experimental results show that,compared with the traditional speed and pressure control method,the control method presented in the paper can reduce concussion on the roof in the process of switching from speed control to pressure control,and can improve support efficiency.Research findings can provide a theoretical basis for the development and control strategy of forepoling equipment.