Fully closed-loop control system and method of press machine based on finite control set sensorless

Abstract

The present invention belongs to the field of control technology and metal forming technology, and specifically relates to a sensorless full-closed-loop control system and method for a press machine based on a finite control set. The present invention uses the difference between the forming process curve and the actual position of the slider as the control command position input of the whole machine control system, establishes a dynamic model, and calculates the torque as the input of the torque prediction control algorithm. The present invention sets a sensorless control algorithm module and a predicted torque algorithm module of a finite control set in the servo motor driver, calculates the rotational speed and electromagnetic torque prediction values, and finally obtains a value function. The slider position information can be added to the value function to control the slider position without overshooting, and the dynamic performance is significantly improved. The anti-interference performance of the motor servo driver is improved and the reliability is also significantly improved, and the cost of the servo motor is greatly reduced.

Description

Technical Field

[0001] The invention belongs to the field of control technology and metal forming technology, and in particular relates to a sensorless full-closed-loop control system and method for a press machine based on a finite control set. Background Art

[0002] There are three ways to control the position of the slider of a servo press, namely open loop, semi-closed loop and full closed loop. Open loop is a position closed loop control method that does not use any servo press; semi-closed loop is a position closed loop control method that uses other position closed loops except the slider; full closed loop is a position control method that uses a slider feedback closed loop. The servo motor of the servo press replaces the ordinary induction motor, and uses direct drive or a primary or secondary reduction mechanism to drive the crank or connecting rod mechanism, cancels the brake and clutch, and the final actuator is still the slider. The reference "The Development of the Latest Servo Press and Future Trends" written by Professor Lu Yan clearly states the main composition and basic transmission structure of the servo press, but does not clearly explain the control process and control method of the servo press slider. According to the current industry practice, the forming process curve of the servo press is generated according to the key point design of the upper computer human-computer interaction interface, and the motor motion curve is approximately calculated through the corresponding formula of the transmission system, and the servo press is controlled by using the rapidity and adjustment function of the servo driver. The displacement parameter of the press is the basic parameter for controlling the action of the press. The displacement of the slider of the crank / connecting rod press is nonlinearly related to the angle of rotation of the crank / connecting rod. Generally, the position encoder is installed at the crankshaft end to collect the crankshaft's operating angle signal, and the slider displacement signal required for press control is calculated using an approximate formula. However, due to factors such as the motion gap and part tolerance of the connecting rod and the reduction mechanism, the actual collected signal can only roughly reflect the displacement of the slider, which will cause a large error. Some invention patent applications, such as the public content of CN102183911A, use a magnetic grating ruler to control the position accuracy of the slider, which can achieve a control accuracy of 0.01mm, but there are still the following three problems: first, a general servo driver is still used to implement the motor control algorithm; second, the entire implementation process still needs to perform mathematical conversion of the nonlinear system to the motor side for control; third, the motor controller also needs to collect the position of the motor to implement the motor control algorithm. The above three shortcomings will make it impossible for the slider to be controlled to the given position in the shortest time or within a reasonable time, resulting in poor dynamic performance and possible overshoot during the position control process (if the slider position overshoots, it means that it exceeds the position set by the user, and the formed workpiece may break and wrinkle). In addition, since the motor position sensor is sometimes affected by signal interference or sensor failure, the reliability and stability of the system are greatly reduced. Summary of the invention

[0003] In order to solve the deficiencies of the prior art, the present invention provides a sensorless full-closed-loop control system and method for a press machine based on a finite control set.

[0004] The present invention is achieved through the following technical solutions:

[0005] A sensorless press full closed-loop control system based on a finite control set comprises a servo press, wherein the whole machine electronic control system of the servo press is connected to a human-machine interaction platform, the human-machine interaction platform inputs key points of a process curve and transmits them to the whole machine electronic control system, and displays key status information at the same time; the whole machine electronic control system is connected to a servo motor driver, the servo motor driver receives control instructions from the whole machine electronic control system, the servo motor driver is connected to the servo motor through a cable, the servo motor is rigidly connected to a reduction mechanism, the reduction mechanism is connected to a connecting rod mechanism, and the connecting rod mechanism is connected to a slider; a balancing cylinder is installed on both sides of the slider, a mold adjustment motor is installed on the slider, the mold adjustment motor is used to complete the slider fine adjustment of the servo press, a slider position sensor is installed near the slider position, the slider position sensor is connected to the whole machine electronic control system, and the slider position sensor transmits feedback information of the actual position of the slider to the whole machine electronic control system; a position sensorless control algorithm module based on a finite control set is added to the servo motor driver, and the position sensorless control algorithm module based on a finite control set comprises a sensorless control algorithm module and a torque prediction control algorithm module of a finite control set:

[0006] Sensorless control algorithm module: performs current sampling and signal processing; discretizes the state equation of the induction motor, estimates the speed, and transmits the final estimated speed result to the torque prediction control algorithm module of the finite control set as input;

[0007] The torque prediction control algorithm module of the finite control set takes the given torque output of the dynamic model and the estimated value output of the speed by the sensorless control algorithm module as input; performs electromagnetic torque prediction, calculates the value function, and adds the slider position information to the value function to control the slider position without overshoot.

[0008] Preferably, the slider position sensor is a high-precision grating ruler or a magnetic linear position sensor.

[0009] Based on the above finite control set sensorless press full closed-loop control system, a finite control set sensorless press full closed-loop control method includes the following steps:

[0010] Step 1: Input the key points of the process curve on the human-computer interaction platform and transmit them to the whole electronic control system of the servo press;

[0011] Step 2: The whole machine electronic control system generates a process curve that conforms to the kinematics of the servo press from the key points of the process curve input by the human-machine interaction platform according to the constraints of the servo press. The output result is a forming process curve, which is implemented using the process curve interpolation algorithm in the whole machine electronic control system.

[0012] Step 3: Establish a dynamic model in the whole machine electronic control system, and use the difference between the forming process curve and the actual position of the slider as the input of the dynamic model. The actual position of the slider is collected by the slider position sensor and fed back to the whole machine electronic control system, and the given torque is calculated and output according to the dynamic model;

[0013] Step 4: The sensorless control algorithm module estimates the speed of the servo motor, and uses the estimated value of the speed as the input of the torque prediction control algorithm module based on the finite control set, and uses the given torque output in step 3 as the input of the torque prediction control algorithm module of the finite control set; then the torque prediction control algorithm module of the finite control set predicts and calculates the electromagnetic torque to obtain the electromagnetic torque prediction value, and obtains the stator voltage equation and the stator current equation through the electromagnetic torque prediction value, and then obtains the value function of the optimal control law for the next step. The torque prediction control algorithm module of the finite control set adds the slider position information to the value function to control the slider position without overshoot.

[0014] As a preferred option:

[0015] In the step 2, a smooth forming process curve is generated by a piecewise polynomial curve interpolation algorithm.

[0016] In the step three, a dynamic model of the servo press is established by using Lagrange's theorem, Hamilton's theorem and Jacobian matrix.

[0017] In the step three, the output given torque is the motor torque or a result that can be linearly converted into torque.

[0018] In the step three, the geometric restrictions and the complete constraint relationship are combined in the dynamic model, a reasonable degree of freedom is selected as 1, and the crank angle is used to directly simplify the expression of the crank connecting rod into the form of a mathematical equation.

[0019] In step 4, the sensorless control algorithm module estimates and calculates the servo motor speed, including the following steps:

[0020] Step A: Discretize the state equation of the induction motor;

[0021] Step B: Calculate the estimated rotation speed.

[0022] The estimation calculation of the rotation speed in the above step B includes the following steps: 1) calculating the state prediction value; 2) calculating the state covariance matrix; 3) calculating the Kalman gain matrix; 4) estimating the state vector; 5) updating the state covariance matrix.

[0023] In step 4, the torque prediction control algorithm of the limited control set includes the following steps:

[0024] Step C: using the estimated value of the rotational speed in step 4 and the given torque output in step 3 as inputs to the torque prediction control algorithm module of the finite control set;

[0025] Step D: Calculate the predicted value of electromagnetic torque;

[0026] Step E: Obtain the squirrel cage stator voltage equation and stator current equation according to the electromagnetic torque prediction value, and finally obtain the value function.

[0027] Beneficial effects of the present invention:

[0028] 1. The present invention can greatly improve the absolute control accuracy of the slider position within the full stroke range of the servo press, and improve the absolute control accuracy of the slider position from 0.1mm to 0.01mm; the repeat positioning accuracy can be improved by one order of magnitude on the basis of the original control accuracy;

[0029] Second, it solves the overshoot problem in the position control mode of the traditional servo press and improves the dynamic performance of the slide position control;

[0030] 3. The servo motor position sensor is eliminated, the servo motor cost is reduced, the reliability is greatly improved, and the system's anti-interference performance is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the fully closed-loop basic architecture of the servo press of the present invention.

[0032] Figure 2 This is the framework diagram of the sensorless control method for servo press based on finite sets.

[0033] In the figure, 1 is the whole machine electronic control system, 2 is the human-machine interaction platform, 3 is the servo motor driver, 4 is the servo motor, 5 is the balancing cylinder, 6 is the slider, 7 is the mold adjustment motor, and 8 is the slider position sensor. DETAILED DESCRIPTION

[0034] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application belong to the protection scope of the present invention.

[0035] The sensorless press full closed-loop control system based on finite control set of the present invention includes a servo press, and the whole machine electronic control system 1 of the servo press is the control core of the whole system, which can control and process signals of the press logic unit. The whole machine electronic control system 1 is connected to the human-computer interaction platform 2, and the human-computer interaction platform 2 can input the key points of the process curve and transmit them to the whole machine electronic control system 1 of the servo press, and display the key status information at the same time.

[0036] The whole machine electronic control system 1 of the servo press is connected to the servo motor driver 3, the servo motor driver 3 receives the control instruction from the whole machine electronic control system 1, the servo motor driver 3 is connected to the servo motor 4 through a cable, the servo motor 4 is rigidly connected to the reduction mechanism, the reduction mechanism is connected to the connecting rod mechanism, and the connecting rod mechanism is connected to the slider 6. The servo motor 4 drives the reduction gear of the reduction mechanism to rotate through the rigid connection, and the crankshaft on the reduction gear output drives the linkage of the connecting rod, so that the slider 6 can complete the final up and down movement. The working principle of the press is common knowledge and will not be introduced in detail here.

[0037] The balancing cylinder 5 is installed on both sides of the slider 6. The main function of the balancing cylinder 5 is to generate a force equal to the gravity of the slider 6 and is driven by a hydraulic or pneumatic device. A mold adjustment motor 7 is also installed on the slider 6. The mold adjustment motor 7 is mainly used to complete the fine adjustment of the slider 6 of the servo press. A slider position sensor 8 is installed near the position of the slider 6 to provide feedback information on the position of the slider 6. The installed slider position sensor 8 is connected to the whole machine electronic control system 1 to transmit the feedback information of the actual position of the slider 6 to the whole machine electronic control system 1. Preferably, a high-precision grating ruler or a magnetic linear position sensor is installed near the position of the slider 6.

[0038] The present invention cancels the existing servo motor position sensor at the servo motor 4 , and no longer installs position sensors such as photoelectric encoders at the servo motor 4 , and then adds a position sensorless control algorithm module based on a finite control set to the servo motor driver 3 as a replacement.

[0039] The position sensorless control algorithm module based on the finite control set includes two parts, namely the sensorless control algorithm module and the torque prediction control algorithm module of the finite control set. The functions of the two algorithm modules are introduced below:

[0040] Sensorless control algorithm module: includes discretizing the state equation of the induction motor to estimate the speed; performing current sampling and signal processing, etc., and transmitting the final estimated speed result to the torque prediction control algorithm module of the finite control set, and using it as the input of the torque prediction control algorithm module of the finite control set.

[0041] Torque prediction control algorithm module of finite control set: The torque prediction control of finite control set has two inputs, one is the given torque output of the dynamic model, and the other is the estimated value output of the speed by the sensorless control algorithm module; the torque prediction control algorithm module of finite control set includes the selection and optimization of the switch state of the motor power model, the selection and calculation of the value function, the realization of the torque prediction equation, etc. The torque prediction control algorithm can be entered according to the torque command given by the dynamic model. The torque prediction control of finite control set can add the position information of slider 6 to the value function to control the position of slider 6 without overshoot.

[0042] The present invention provides a sensorless press full closed-loop control method based on a finite control set, comprising the following steps:

[0043] Step 1: Input the key points of the process curve on the human-computer interaction platform 2 and transmit them to the whole machine electronic control system 1 of the servo press.

[0044] Step 2: The whole machine electronic control system 1 generates a process curve that conforms to the kinematics of the servo press according to the constraints of the servo press from the key points of the process curve input by the human-machine interaction platform 2, and the output result is a forming process curve. The forming process curve is implemented using the process curve interpolation algorithm in the whole machine electronic control system 1.

[0045] Step 3: A dynamic model is established in the whole machine electronic control system 1, and the difference between the forming process curve and the actual position of the slider 6 is used as the input of the dynamic model. The actual position of the slider 6 is collected by a high-precision grating ruler or a magnetic linear position sensor installed near the position of the slider 6 and then fed back to the whole machine electronic control system 1. According to the above-established dynamic model, the given torque is calculated and output, and the given torque is the motor torque or the result that can be linearly converted into torque.

[0046] Step 4: The sensorless control algorithm module estimates the speed of the servo motor, and uses the estimated value of the speed as the input of the torque prediction control algorithm module based on the finite control set, and uses the given torque output in step 3 as the input of the torque prediction control algorithm module of the finite control set; then the torque prediction control algorithm module of the finite control set predicts and calculates the electromagnetic torque to obtain the electromagnetic torque prediction value, and obtains the stator voltage equation and the stator current equation through the electromagnetic torque prediction value, and then obtains the value function of the optimal control law for the next step, so that the torque prediction control algorithm module of the finite control set can add the position information of the slider 6 to the value function to control the position of the slider 6 without overshoot.

[0047] In the above preferred embodiment, in step 2, a smooth forming process curve is generated by a piecewise polynomial curve interpolation algorithm.

[0048] In the above preferred embodiment, in step 3, the dynamic model of the servo press is established by using Lagrange's theorem, Hamilton's theorem and Jacobian matrix. In combination with geometric constraints and complete constraint relationships, a reasonable degree of freedom is selected as 1, and the crank angle can be used to directly simplify the expression of the crank connecting rod into a mathematical equation. The output of the dynamic model is the motor torque output by the dynamic calculation or the result that can be linearly converted into torque, as follows:

[0049]

[0050] Wherein Γ=TL, T is the kinetic energy of the transmission components of the servo press, L is the potential energy of the transmission components of the servo press, θ is the crankshaft angle of the servo press or the selected key angle, and τ is the calculated output given torque.

[0051] In the above preferred embodiment, in step 4, the sensorless control algorithm module estimates and calculates the servo motor speed, including the following steps:

[0052] Step A: Discretize the state equation of the induction motor

[0053] The state equation of the induction motor can be written as

[0054] px=Ax+Bu (2)

[0055] y=Cx (3)

[0056] where x = [i oα ,i oβ , ψ rα , ψ rβ ],u=[u oα ,u oβ ],y=[i sα ,i sβ ]; six variables i sα 、i sβ , ra , rβ 、u sα 、u sβ They are the alpha phase current, beta phase current, alpha phase flux, beta phase flux, alpha phase voltage, beta phase voltage in the two-phase stationary coordinate system respectively; p represents the differential operator;

[0057]

[0058]

[0059] in L r Rotor inductance, L s Stator inductance, L m Mutual inductance, Rs Stator resistance, R r Rotor resistance, ω r Rotor speed.

[0060] When the current sampling period is very small or the load inertia is relatively large, the change in speed can be ignored. In the speed sensorless control, the speed is unknown and the equation is nonlinear, so the fifth-order discrete augmented matrix can be obtained.

[0061] px=A d x+B d u (4)

[0062] y=C d x (5)

[0063] where x = [i sα ,i sβ , ψ rα , ψ rβ ,ω r ],u=[u sa ,u sβ ];

[0064]

[0065]

[0066] In the process of discretizing the continuous equation, we know that A d =I+AT; B d =BT; C d =C, T is the sampling period.

[0067] Step B: Calculate the estimated speed

[0068] The recursive steps for speed and torque estimation using the extended Kalman filter are as follows:

[0069] 1. Calculate the state prediction value

[0070]

[0071] 2. State covariance matrix

[0072]

[0073] 3. Calculate the Kalman gain matrix

[0074]

[0075] 4. Estimated state vector

[0076]

[0077] 5. Update the state covariance matrix

[0078]

[0079] Where F and H are A d and C d The Jacobian matrix of , k represents the k-th step.

[0080] In the above, the superscript "~" represents a predicted value, and the superscript "^" represents an estimated value.

[0081] In the above preferred embodiment, in step 4, the torque prediction control algorithm of the finite control set includes the following steps:

[0082] Step C: Use the estimated value of the rotational speed in step 4 and the given torque output in step 3 as inputs to the torque prediction control algorithm module of the finite control set.

[0083] Step D: Calculate the predicted electromagnetic torque

[0084] Based on the Euler discretization method, the rotor and stator flux equations of the squirrel cage induction motor are expanded to obtain

[0085]

[0086]

[0087] The stator flux prediction can be obtained by the stator voltage equation

[0088]

[0089] The next step is to use the Euler formula to discretize and get the stator flux prediction value.

[0090] ψ s (k+1)=ψ s (k)+T s v s -R s T s i s (k) (14)

[0091] The predicted value of electromagnetic torque is

[0092]

[0093] Step E: Get the value function

[0094] According to the predicted value of electromagnetic torque, the squirrel cage stator voltage equation can be obtained, and the stator current equation can be obtained through the squirrel cage stator voltage equation, which are as follows:

[0095]

[0096]

[0097] The optimal control law for predicting the next step is reflected by the value function:

[0098] g=|T * -T(k+1)|+λ0|||ψ s * ||-||ψ s (k+1)||+|pos * -pos| (18)

[0099] where ψ r (k) represents the k-th step rotor flux, ψ s (k) represents the stator flux at step k, v s represents the stator voltage, i s represents the stator current, T(k+1) represents the motor torque at the k+1th step, in the above formula, Im represents the imaginary part, j represents the imaginary part, λ0 represents the weight sign, pos represents the actual position feedback value of slider 6, pos * represents the position value of the given slider 6 forming process curve, ψ s * Indicates a given flux value, n p Indicates the number of motor pole pairs. Here T * Represents the given torque value, which is equal to the given torque τ output by the press dynamics model.

[0100] According to the optimization result of the value function, the switching state of the three-phase power unit of the servo motor driver can be obtained, the IGBT gate-level action can be controlled, the current output of the servo driver can be realized, and the servo motor can be controlled.

[0101] In this way, the torque prediction control algorithm module of the finite control set can add the position information of the slider 6 to the value function to control the position of the slider 6 so that overshoot does not occur.

[0102] The existing technology can only feedback the position of the slider 6 through the crankshaft angle sensor to perform semi-closed loop position control. This method can solve the angle error at the crank, but it still cannot eliminate the error of the connecting rod gap of the servo press and the error caused by the deformation of the machine body. The conventional servo press method is to convert the mechanical transmission parts other than the motor into mathematical relationships, and realize motion control by controlling the servo motor 4. The control method is an open-loop control method. This method may cause the slider 6 position to overshoot, affecting the workpiece forming quality, and cannot guarantee the absolute position control accuracy of the slider 6.

[0103] The advantages of the present invention are that the absolute position of the servo press slide 6 can be accurately controlled without overshoot, the dynamic performance is significantly improved, and the transmission structure of the servo press is integrated into the control algorithm. Since the position encoder of the motor is eliminated, the anti-interference performance of the servo motor driver 3 is improved and the reliability is also significantly improved, and the control cost of the servo motor 4 is greatly reduced.

[0104] The embodiment described above is only one of the more preferred specific implementations of the present invention. Common changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A control method for a fully closed-loop control system of a press machine based on a finite control set sensorless system, characterized in that: The sensorless press full closed-loop control system based on a finite control set comprises a servo press, wherein the whole machine electronic control system (1) of the servo press is connected to a human-machine interaction platform (2), the human-machine interaction platform (2) inputs key points of a process curve and transmits them to the whole machine electronic control system (1), and displays key status information at the same time; the whole machine electronic control system (1) is connected to a servo motor driver (3), the servo motor driver (3) receives control instructions from the whole machine electronic control system (1), the servo motor driver (3) is connected to a servo motor (4) via a cable, the servo motor (4) is rigidly connected to a reduction mechanism, the reduction mechanism is connected to a connecting rod mechanism, and the connecting rod mechanism is connected to a slider (6); the slider A balancing cylinder (5) is installed on both sides of the slider (6), a mold adjustment motor (7) is installed on the slider (6), and the mold adjustment motor (7) is used to complete the fine adjustment of the slider (6) of the servo press. A slider position sensor (8) is installed near the position of the slider (6), and the slider position sensor (8) is connected to the whole machine electronic control system (1). The slider position sensor (8) transmits feedback information of the actual position of the slider (6) to the whole machine electronic control system (1); a position sensorless control algorithm module based on a finite control set is added to the servo motor driver, and the position sensorless control algorithm module based on a finite control set includes a sensorless control algorithm module and a torque prediction control algorithm module of a finite control set: Sensorless control algorithm module: performs current sampling and signal processing; discretizes the state equation of the servo motor, estimates the speed, and transmits the final estimated speed result to the torque prediction control algorithm module of the finite control set as input; The torque prediction control algorithm module of the finite control set takes the given torque output of the dynamic model and the estimated value output of the speed by the sensorless control algorithm module as input; performs electromagnetic torque prediction, calculates the value function, adds the position information of the slider (6) to the value function, and controls the position of the slider (6) to prevent overshoot; The sensorless press full closed-loop control method based on a finite control set comprises the following steps: Step 1: Input the key points of the process curve on the human-computer interaction platform (2) and transmit them to the whole machine electronic control system of the servo press (1); Step 2: The whole machine electronic control system (1) generates a process curve that conforms to the kinematics of the servo press according to the constraint conditions of the servo press from the key points of the process curve input by the human-machine interaction platform (2), and the output result is a forming process curve. The forming process curve is implemented by using the process curve interpolation algorithm in the whole machine electronic control system (1); Step 3: A dynamic model is established in the whole machine electronic control system (1), and the difference between the forming process curve and the actual position of the slider (6) is used as the input of the dynamic model. The actual position of the slider (6) is collected by the slider position sensor (8) and fed back to the whole machine electronic control system (1), and a given torque is calculated and output according to the dynamic model; Step 4: The sensorless control algorithm module estimates the speed of the servo motor, and uses the estimated value of the speed as the input of the torque prediction control algorithm module based on the finite control set, and uses the given torque output in step 3 as the input of the torque prediction control algorithm module of the finite control set; then the torque prediction control algorithm module of the finite control set predicts and calculates the electromagnetic torque to obtain the electromagnetic torque prediction value, and obtains the stator voltage equation and the stator current equation through the electromagnetic torque prediction value, and then obtains the value function of the optimal control law for the next step. The torque prediction control algorithm module of the finite control set adds the position information of the slider (6) to the value function to control the position of the slider (6) without overshoot.

2. The control method of the finite control set sensorless press full closed-loop control system according to claim 1 is characterized in that: The slider position sensor (8) is a high-precision grating ruler or a magnetic linear position sensor.

3. The control method of the finite control set sensorless press full closed-loop control system according to claim 1 is characterized in that: In the step 2, a smooth forming process curve is generated by a piecewise polynomial curve interpolation algorithm.

4. The control method of the finite control set sensorless press full closed-loop control system according to claim 1 is characterized in that: In the step three, a dynamic model of the servo press is established by using Lagrange's theorem, Hamilton's theorem and Jacobian matrix.

5. The control method of the finite control set sensorless press full closed-loop control system according to claim 1, characterized in that: In the step three, the output given torque is the motor torque or a result that can be linearly converted into torque.

6. The control method of the finite control set sensorless press full closed-loop control system according to claim 1, characterized in that: In the step three, the geometric restrictions and the complete constraint relationship are combined in the dynamic model, a reasonable degree of freedom is selected as 1, and the crank angle is used to directly simplify the expression of the crank connecting rod into the form of a mathematical equation.

7. The control method of the finite control set sensorless press full closed-loop control system according to claim 1 is characterized in that: In step 4, the sensorless control algorithm module estimates and calculates the servo motor speed, including the following steps: Step A: discretize the state equation of the servo motor; Step B: Calculate the estimated rotation speed.

8. The control method of the finite control set sensorless press full closed-loop control system according to claim 7, characterized in that: The estimation calculation of the rotation speed in step B includes the following steps: 1) Calculate the state prediction value; 2) State covariance matrix; 3) Calculate the Kalman gain matrix; 4) Estimate the state vector; 5) Update the state covariance matrix.

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