78 results about "Step response" patented technology

The invention provides an intelligent control method and system based on electro-hydraulic linkage. The method comprises the steps that multi-mode environment parameters are collected, a digital twin environment model is constructed, and data are synchronized with an electro-hydraulic servo system in real time. And establishing a nonlinear model, identifying parameters by using a least square method and a recursive least square method, verifying the precision through a step response test, and updating. And constructing an adaptive LSTM neural network inverse model to output a control voltage signal. And the signal is subjected to weighted fusion with the output of a PID controller, and the PID controller dynamically adjusts a gain parameter according to an error integral term to generate a control instruction to drive the system. According to the invention, the LSTM inverse model provides feed-forward compensation, the PID controller realizes feedback correction, and the LSTM inverse model and the PID controller are complementary. Meanwhile, based on a related nonlinear model and a parameter self-adaptive updating mechanism, the influence of working condition change is accurately described, and high-precision control of the electro-hydraulic servo system under the complex working condition is achieved.

The invention relates to the technical field of response time testing of electro-hydraulic proportional valves, and discloses a response time testing method and system of an electro-hydraulic proportional valve, and the method comprises the steps: collecting multi-point pressure, step response, pipeline length and medium parameters, and unifying the time reference to obtain an original pressure sequence; constructing an inverse filter spectrum to remove damping interference so as to recover a sharp peak value; lagging offset is calculated according to pipeline and medium parameters, time delay compensation is carried out, and an alignment sequence is obtained; intercepting a non-stationary segment to eliminate residual delay deviation; constructing a response dynamic data set, extracting harmonic frequency domain representation, and reconstructing a pressure sequence through inverse transformation and superposition of compensation factors; and calculating a deviation integral quantity, adjusting a dynamic compensation parameter, performing weighted correction, and outputting an optimized reconstruction response sequence. According to the method, accurate reconstruction of the real pressure response of the proportional valve can be realized, so that the accuracy and the reliability of response time testing are improved.

The invention discloses a first-order linear active disturbance rejection controller parameter setting method based on a phase margin method, and the method comprises the following steps: S1, obtaining simplified first-order inertia delay object parameters through an open-loop step response curve on site, and the simplified first-order inertia delay object parameters comprise the steady-state gain K, the inertia time constant T and the delay time tau of a controlled object; and S2, discussing and setting parameters of the controller according to conditions according to the ratio theta of the delay time tau of the controlled object to the inertia constant T. According to the first-order linear active-disturbance-rejection controller parameter setting method based on the phase angle margin method, the phase angle margin of the first-order linear active-disturbance-rejection controller is subjected to theoretical analysis, and the phase angle margin of the first-order linear active-disturbance-rejection controller and a closed-loop stable system of a controlled object is directly configured; and therefore, the problem of overshoot in parameter setting of the linear active disturbance rejection controller can be solved.

The invention relates to the technical field of control regulation, in particular to a supercritical unit variable load rate dynamic compensation control method, which comprises the following steps: acquiring unit operation data, performing credibility restoration, and outputting a credible parameter set; a time sequence mapping table is constructed based on the credible data, and boiler heat storage lag time, steam turbine control valve delay and a steam temperature interstage coupling coefficient are quantified; correcting the boiler water supply feedforward instruction by using the heat storage lag time to generate a compensated water supply instruction; according to the time sequence mapping table and the main steam pressure change rate, a multi-genetic algorithm is adopted to optimize a control valve constraint rule, and a dynamically constrained control valve action instruction is generated; an inter-stage coupling coefficient is called to generate a swing angle compensation amount, and water spraying temperature reduction disturbance is blocked; safety locking parameters are monitored to trigger buffering intervention in a grading mode, and compensation instructions are integrated to implement cooperative correction. The problem of out-of-step response of multiple execution units under the variable load working condition is solved, and the unit adjusting rate and the control stability are remarkably optimized.

The invention relates to a gas turbine system predictive control method, device, equipment and medium, and relates to the technical field of gas turbine control, and the method comprises the steps: building a transfer function model of a gas turbine system at a plurality of preset load points through a step response experiment, a prediction controller is designed based on the transfer function models corresponding to the different load points, so that a control increment output by the prediction controller is obtained, and the prediction controller comprises a plurality of sub-prediction controllers corresponding to the different load point models; correcting the control increment which does not accord with a preset constraint condition based on an improved He-Make algorithm; and based on the deviation between the control increment corresponding to each sub-prediction controller and the actual output value, performing weighting processing on the control increment sequence corresponding to each sub-controller by using an improved recursive Bayesian weighting algorithm to obtain a final control increment. According to the method, the operation stability and the response speed of the heavy duty gas turbine system can be remarkably improved, and the strong performance advantage is shown in the aspect of set value tracking.

The invention provides a prediction control method and device adaptive to a process industry model and electronic equipment. The method comprises the following steps: acquiring a historical controlled quantity sequence, a historical controlled quantity sequence and a future controlled quantity sequence of the chemical device; a unit step response prediction model is constructed, the historical controlled quantity sequence and the historical controlled quantity sequence are input into the unit step response prediction model, unit step response based on the controlled quantity and the controlled quantity is obtained, and the unit step response prediction model comprises a coding layer, an attention layer, a decoding layer and a smoothing layer; constructing a controlled quantity prediction model, and inputting the historical controlled quantity sequence, the historical controlled quantity sequence, the future controlled quantity sequence and the unit step response into the controlled quantity prediction model to obtain a future controlled quantity sequence corresponding to the future controlled quantity sequence; and the future controlled quantity sequence is controlled to be within a set range by adjusting the future controlled quantity sequence. The problem that in the prior art, prediction of nonlinear variables in the field of process industrial control is low in accuracy is solved.

The invention provides a self-adaptive deep learning prediction control method and device suitable for the process industry. Comprising the following steps: constructing an all-condition dynamic model of a target control variable based on a deep learning technology according to historical control information of the process industry, and performing segmentation processing on a change gain curve of the all-condition dynamic model based on a self-adaptive segmentation algorithm of a threshold value to obtain a segmented linear gain model; a piecewise linear variable constraint of the piecewise linear gain model is determined, and an optimization target of a target control variable is determined based on the piecewise linear variable constraint; and obtaining a step response sequence of the target control variable at the current working condition point based on the piecewise linear gain model, and predicting a future control execution sequence of the target control variable according to the step response sequence and the optimization target. The problem that an existing predictive control method generally constructs a mapping relation between a control variable and a controlled variable based on a linear model, the nonlinear characteristic of the control variable cannot be accurately reflected, and then the predictive control accuracy is low is solved.

The invention relates to the technical field of electric power simulation, and discloses a hardware-in-the-loop simulation-oriented new energy equipment model verification method and system, and the method comprises the steps: constructing a new energy equipment basic model based on a physical equation, carrying out the compensation of a dynamic working condition error through combining with an LSTM neural network, and generating a hybrid parameterized model; fitting voltage and current data through a particle swarm optimization algorithm, and dynamically adjusting impedance parameters to complete model calibration; a time domain step response test, frequency domain characteristic analysis and a voltage sag fault experiment are executed on a hardware-in-loop platform, and the performance of the model is verified in a multi-dimensional mode; and generating a standardized verification report containing a steady-state error and a simulation step length index based on the deviation between the dynamic response curve and the measured data. According to the method, a mechanism model and a data driving technology are fused, the problems that dynamic characteristic adaptation is insufficient and parameter calibration depends on experience in traditional verification are solved, and the simulation precision and verification efficiency of the model under complex working conditions are improved.

The invention discloses a single-loop droop control method and system for a wind generating set, and the method comprises the following steps: constructing a doubly-fed fan-power converter-power grid three-module coupling model, and completing the dynamic adaptation of the characteristics of a doubly-fed fan of a single-loop droop control architecture without inner-loop current control; based on the input signal-model collaborative integration body and the adaptive architecture, MIMO-GBC is adopted to analyze a phase margin and a resonance peak value of an open-loop transfer function matrix eigenvalue of a dynamic small signal model, and double risks are identified in a full slip rate interval; aiming at the resonance risk, a current induction type virtual impedance strategy is adopted; aiming at insufficient phase margin, adopting a transient phase calibration strategy; and according to the real-time slip ratio of the DFIG and the stator power change, inter-partition linkage optimization is carried out on the virtual resistance and the phase calibration angle so as to minimize a dual-power step response fluctuation square mean value, a parameter setting period and a rotor side converter control period are synchronously matched, and all-working-condition stable control is realized.

This invention proposes a rapid and non-destructive method for identifying the resonant frequency of heavy-duty mechanisms. The load-end speed curves and motor-end speed curves under closed-loop and open-loop conditions at the motor end are obtained using the speed step response method and the current step response method, respectively. By performing an FFT transform on the two speed curves, the resonance peak is obtained, allowing for rapid measurement of the structural resonant frequency and the combined resonant frequency. This method eliminates the need to purchase an additional resonance analyzer, reducing measurement costs, and avoids the damage to large, heavy-duty servo mechanisms caused by sinusoidal frequency sweep measurements. It can not only be used for rapid identification of structural resonant frequencies but also to guide the design of servo controllers.

The invention relates to the technical field of industrial process automatic control, and discloses an automatic control method for a water sample analysis process, which comprises the following steps: establishing a unit step response reference model for representing a normalized standard track of a controlled object; iteratively searching an optimal amplitude scaling and time elastic factor in the two-parameter search space to minimize the fitting residual error of the reference model and the real-time data; the optimal amplitude scaling factor is utilized to determine a projection steady-state value to drive an execution unit, and the sampling interval is adaptively adjusted according to the optimal time elastic factor, the time elastic factor is introduced to realize closed-loop compensation of system kinetic parameter drift, a steady-state target can be accurately locked in an unbalanced state, and the stability of the system is improved. And the problem of control model mismatch caused by device aging or environment fluctuation is solved.

The invention belongs to the technical field of automation control, and particularly relates to a control parameter optimization method and system for a multistage reaction kettle, and the method comprises the steps: collecting key operation data of a series multistage reaction kettle at each moment in real time, and constructing an initial temperature sequence and an initial valve opening sequence after standardization and adaptive filtering denoising; indexes such as temperature fluctuation standard deviation are calculated based on the initial temperature sequence, the temperature deviation degree is obtained through normalized weighted fusion, and parameters such as the Arrhenius law and the actually measured temperature are combined to construct a reaction nonlinear strength index; on the basis of the index coupling initial valve opening degree sequence change rate, a model vector self-adaptive correction coefficient is obtained in combination with parameters such as a smooth factor; and correcting a basic step response vector controlled by the dynamic matrix by using the coefficient, solving an optimal valve opening adjustment amount, calculating an execution value, and outputting the execution value to an execution mechanism to complete regulation and control, thereby realizing full-cycle optimization of control parameters. According to the invention, the control accuracy of the multi-stage reaction kettle is improved.

The invention discloses a parallel formation low-bandwidth pulse switching control method and device and a storage medium, and the method comprises the following steps: predicting an initial duty ratio according to the voltage relation of Buck-Boost topology; generating a feedforward prediction duty ratio through a feedforward compensation mechanism; dynamically selecting a loop switching mode according to a current error absolute value or a current change rate, and determining a current loop duty ratio; the loop switching mode comprises a current open-loop control mode and a current closed-loop control mode; when the loop switching mode is a current closed-loop control mode, a PI parameter is dynamically adjusted according to a current error value; and when the current average change rate and the current error meet the compensation condition, the current loop is controlled to enter steady-state control. According to the invention, the current switching speed and precision are obviously improved, the step response overshoot is greatly reduced, and the steady-state error minimization is ensured.

The application relates to the technical field of servo motor driving, and particularly discloses an inertia identification method based on double-frequency sinusoidal speed instructions, two different frequency sinusoidal speed instructions are sent to a motor by a servo driver, according to Newton's second law, a motion equation of a rotating system, a speed signal or an acceleration signal is multiplied by both sides of the motion equation of the rotating system, and integral operation is carried out in a complete period; for the test of the frequency omega1, the collected torque T e1 (t) is integrated with the acceleration, and thus the rotational inertia J can be directly solved. In the method, the speed instruction is a sinusoidal wave, compared with the trapezoidal acceleration and deceleration method and the step response method, the instruction is smoother, mechanical impact is small, and in addition, technical difficulties existing in the single-frequency sinusoidal excitation method can be avoided.

The invention discloses a hydraulic underground drill rig rotating speed control method based on load compensation. The method comprises the following steps that 1, a dynamic model and a steady-state model of a hydraulic underground drill rig rotating system are established; 2) based on a step response experiment result of the drilling machine rotation system, identifying dynamic model parameters of the drilling machine rotation system; 3) based on the dynamic model obtained through identification in the step 2), designing an extended state observer, realizing estimation of load torque influence and carrying out feed-forward compensation; 4) designing a PI controller by adopting a pole assignment mode based on the dynamic model after feedforward compensation, and realizing tracking of the rotating speed; and 5) designing a dead zone compensator based on the steady-state model, overcoming the dead zone of the valve port, and controlling the input of the steady-state model to be close to the actually required opening degree of the valve port so as to realize rapid tracking response of the rotating speed. The problem of rotation speed fluctuation in the drilling process can be effectively solved, and the stability and safety of the rotation speed of the drilling machine are remarkably improved. The control system has high adaptability, can keep accurate tracking of the rotation speed under different drilling working conditions, and provides effective support for intelligent control of the coal mine drilling machine.

The position-torque double closed-loop servo system parameter optimization control method provided by the invention is stable and rapid in dynamic response. On the basis that a position regulator is composed of first-order advanced feedback of a unit proportionality coefficient and regulation with proportion and integration as main components, a simplest expectation mathematical model of a closed-loop single-zero-point type 3 (a forward channel of the system has three integration links) control system is provided, and the maximum phase angle margin of the system is used as an optimization target. And deriving an analytic formula of system open-loop gain optimization setting, and further providing a position regulator parameter optimization setting control method which enables the position-torque double-closed-loop servo system to have low-overshoot, stable and rapid performance on step response. The method has important guiding significance on design of the position-torque double-closed-loop servo system requiring stable and rapid dynamic response, product development (including experimental equipment), on-site commissioning, debugging and the like, and meanwhile, the design theory of the motor position-torque double-closed-loop servo system is also perfected.

This invention discloses a method for controlling the main steam temperature of a power generation boiler. The method includes collecting step response data of the main steam temperature of the power generation boiler, fitting the data using the least squares method, and establishing a mathematical model of the inertia region and lead-forward region of the main steam control channel of the power generation boiler. Then, a predictive compensation controller is introduced in the parallel feedback loop, and the lag component is separated as a separate term using a constant separation method. Next, the PID parameters are optimized using an artificial fish swarm algorithm, and the optimal solution is substituted into the original parameters. Smith predictive compensation control effectively eliminates the lag effect in the system model, shortens the system settling time, and the artificial fish swarm algorithm significantly improves the controller accuracy, effectively shortens the time for the system to reach the target value, reduces the system overshoot, and minimizes the impact of external disturbances.

The application provides a kind of steam turbine governing system electric power step response simulation error analysis method and device, it is related to electric power equipment performance detection field, including: according to the parameter sample of steam turbine governing system electric power step response, preset sample polynomial is fitted, corresponding peak power arrival time is obtained;According to the sample polynomial and historical sample of fitting, the starting step time and steady state entering time of the parameter sample are determined;According to the peak power arrival time, the starting step time and steady state entering time determine the parameter identification error of the steam turbine governing system electric power step response.The application can determine the parameter identification error of steam turbine governing system electric power step response.

The invention discloses a three-axis holder permanent magnet synchronous motor control method based on an approaching law, and belongs to the technical field of permanent magnet synchronous motor control. According to the method, a composite control strategy of a novel reaching law and a sliding mode disturbance observer (SMC + SMO) is adopted in a speed loop, and a traditional PI controller is adopted in a current loop and a position loop. The novel reaching law fuses elements such as an index item and a terminal item, buffeting is restrained, and the response speed is increased; the sliding mode disturbance observer estimates and compensates interference in real time, and the anti-interference capability is enhanced. Experimental results show that the strategy is fast in rotating speed step response, small in angle step response overshoot and high in anti-jamming capability, and fast response, stability and robustness of the three-axis holder are guaranteed. According to the invention, an effective way is provided for high-precision control of the airborne holder of the unmanned aerial vehicle.

The invention discloses a hybrid control method suitable for a long-stroke rapid cutter servo system, and the method comprises the steps: obtaining a controlled object model according to the sweep frequency of an open-loop system and system identification, and constructing a closed-loop hybrid control algorithm model based on proportional integral differential control, sliding mode control and speed / acceleration feedforward control; by continuously calculating system output and control errors, parameter adjustment of a control algorithm is completed; the hybrid control algorithm model is written into PMAC hardware, step and sine response testing and control parameter optimization adjustment are completed, and high-precision machining of the long-stroke rapid tool servo system is achieved. According to the hybrid control method, the response speed and the control precision of the system can be remarkably improved, nonlinear disturbance in a complex machining task can be adapted, and a high-stability and low-inertia-force solution is provided for ultra-precision machining of a surface microarray, an optical free-form surface and the like.

The present invention belongs to the field of device calibration technology and discloses a rapid calibration method and apparatus suitable for analog devices. The method comprises: constructing an initial simulation model corresponding to a reference analog device, and iteratively optimizing the initial simulation model to obtain a standard simulation model; inputting a step signal into the analog device to be calibrated to obtain step response data at any two moments within a first preset time window; obtaining an actual gain speed based on the step response data at any two moments, and determining that the actual gain speed is not within a preset gain speed range, then determining that the analog device to be calibrated is an abnormal device; conversely, inputting the step response data at the several moments into a standard simulation model, and introducing an oscillation frequency equation to obtain a target simulation model corresponding to the analog device to be calibrated; and determining an actual calibration range based on the prediction of the target simulation model. The present invention greatly shortens the time cost of calibration.

The invention provides a closed-loop control method and system for an on-satellite brushless motor based on differential evolution, and the method comprises the steps: obtaining a step response curve, carrying out the differential mapping coding of a PID parameter, obtaining corresponding differential coding values, connecting the differential coding values in series to form a chromosome representing a possible solution, and forming an initial population. Calculating a fitness parameter of the initial population according to a fitness function; inputting the fitness parameter into a genetic algorithm for calculation, judging whether the current genetic algebra reaches a preset maximum value or not, if so, outputting a current optimal solution, and performing setting based on the PID parameter of the optimal solution; and if not, adding one to the population number, and repeating the steps. According to the chaotic coding method, the chaotic coding is carried out by utilizing the property of a chaotic system, the anti-interference capability is relatively high, the noise interference in the signal transmission process can be effectively reduced, and the reliability of the signal is improved.

The invention discloses a linear active-disturbance-rejection controller and a design method and a parameter setting method thereof, and the design method comprises the steps: building a gain parameter which considers the influence of the order of a controlled object on overshoot in the step response of the controller, and introducing the gain parameter into a linear error feedback control rate; an error component between the output of the linear tracking differentiator and the output of the linear extended state observer is dynamically adjusted, thereby configuring a zero point of a forward channel of the system, i.e., a zero point of a closed-loop system, thereby reducing overshoot. According to the linear active disturbance rejection controller, the input of a linear error feedback control law is provided with a gain parameter, the gain parameter dynamically adjusts an error component between the output of a linear tracking differentiator and the output of a linear expansion state observer, and therefore the zero point of a system forward channel is configured; the zero point is the zero point of the closed-loop system, so that the overshoot is reduced.

The application relates to grid-connected control technology of a converter and aims to provide a cascade energy storage converter inertia damping optimization method suitable for multiple grid conditions. The method comprises the following main steps: grid-connected system modeling, inertia parameter optimization, damping parameter optimization and parameter design under multiple grid conditions. The inertia and damping parameters are optimized through transmission characteristics and step response characteristics, the dynamic response performance and system stability of the cascade energy storage converter can be effectively improved, and the reliability of the voltage source support of the converter is ensured; through establishment of an optimization parameter library and an optimization parameter curve covering multiple grid strengths, the configuration and debugging process of the system is simplified, the complexity and time requirement of parameter adjustment are reduced, and the adaptability of the system under different grid operation conditions is effectively enhanced.

The invention provides an electromechanical control system parameter optimization method and system based on an improved intelligent algorithm. The method belongs to the field of electromechanical control, and discloses a controller structure comprising an active resistance increasing control loop, a PID control loop and a series wave trap group. Aiming at the active resistance increasing control loop and the PID control loop, respectively constructing corresponding multi-target fitness functions in combination with respective control targets; an improved intelligent optimization algorithm is adopted, the value of the multi-target fitness function constructed in a minimized mode is used as an optimization target, collaborative optimization is carried out on parameters of all the control loops, and an optimized control parameter set is obtained; substituting the optimized control parameter set into the controller structure, and performing step response verification in a simulation environment; and deploying the multiple groups of optimized control parameters passing verification in an actual controller to realize real-time adaptive control of the electromechanical system according to different working conditions. According to the method, global optimal control parameters meeting complex constraint conditions can be quickly obtained.

The application relates to the technical field of industrial process automation control, and discloses an automatic control method for a water sample analysis process, which comprises the following steps: establishing a unit step response reference model representing a normalized standard track of a controlled object; iteratively searching for an optimal amplitude scaling and a time elasticity factor in a double-parameter search space, so that the reference model and real-time data are fitted to minimize residual errors; and determining a projection steady-state value by using the optimal amplitude scaling factor to drive an execution unit, and adaptively adjusting a sampling interval according to the optimal time elasticity factor. The application realizes closed-loop compensation for system dynamics parameter drift by introducing the time elasticity factor, can accurately lock a steady-state target under a non-equilibrium state, and solves the problem of control model mismatch caused by device aging or environmental fluctuation.

The application discloses a kind of internal heating type fluidized bed drying temperature control method and system, by mechanism deduction and step response modeling, obtain the transfer function of first-order inertia plus pure lag link, the coupling between two heating pipes is regarded as interference, observer is added in control loop to eliminate dynamic coupling, cooperate with the control strategy of cascade control, effectively reduce the overshoot of internal heating type fluidized bed temperature (T1, T2), reduce steady-state error, improve the stability of production, significantly reduce the labor intensity of operator.The method solves the problem of separate isolated adjustment of each section temperature of the fluidized bed, poor drying effect;Solve the problem that the internal heating type fluidized bed drying process cannot be put into automatic control under full working condition;Solve the problem of dynamically adjusting each section bed temperature according to the demand of moisture content of drying material and accurately controlling;Solve the problem that when winter temperature drops, the steam pipeline of system, the condensate of tube is large, and the bed temperature is out of control and drops.

The invention discloses a fuzzy PID (Proportion Integration Differentiation) initial parameter setting method based on a step response model. The method comprises the following steps: step (1), system identification; step (2), fuzzy PID initial parameter setting; and (3) fuzzy PID dynamic control: performing real-time dynamic correction on the initial parameter group obtained in the step (2) through dynamic correction, and then outputting a control signal adaptive to the current working condition. The system can be directly transplanted to common control platforms such as industrial PLCs and single-chip microcomputers, can meet the requirements of various temperature control scenes such as industrial production, precision experiments and biomedical treatment, and has wide application prospects and popularization values.

This invention relates to the field of response time testing technology for electro-hydraulic proportional valves, and discloses a method and system for testing the response time of electro-hydraulic proportional valves. The method includes: acquiring multi-point pressure, step response, pipeline length, and medium parameters, and unifying the time base to obtain an original pressure sequence; constructing an inverse filter spectrum to remove damping interference and recover sharp peaks; calculating hysteresis offset based on pipeline and medium parameters to perform time delay compensation and obtain an aligned sequence; truncating non-stationary segments to eliminate residual delay deviations; constructing a dynamic response dataset and extracting harmonic frequency domain representations, and reconstructing the pressure sequence by inverse transformation and superimposing compensation factors; calculating the deviation integral, adjusting dynamic compensation parameters and weighting corrections, and outputting an optimized reconstructed response sequence. This method can achieve accurate reconstruction of the true pressure response of the proportional valve, thereby improving the accuracy and reliability of response time testing.

The invention discloses an electric engineering machinery metering pump flow response control method, equipment and a medium, belongs to the technical field of hydraulic control, and aims to solve the technical problems that a metering pump in an existing electric excavator is low in response speed, a hydraulic system has certain inertia delay, and accurate hydraulic control is not facilitated. The method comprises the steps that response demand calculation is conducted on the hydraulic oil energy demand in the constant displacement pump; energy output control under related main pump pressure and overflow protection is carried out on hydraulic oil energy requirements; the output energy of the constant delivery pump and the rotating speed of the motor are subjected to fitting prediction processing under the step response model, and an energy output dynamic prediction model is obtained; and carrying out selective calculation on the energy output dynamic prediction model under related control time domain length and prediction time domain length, carrying out feedback correction, rolling optimization and prediction error correction processing on the energy output dynamic prediction model, and outputting and obtaining an energy output response quantity related to motor rotation speed prediction control.