Motor control mode switching method and device, servo drive device and medium

Abstract

The application discloses a motor control mode switching method and device, a servo driving device and a storage medium. The method comprises the following steps: if a mode switching signal of a motor is received, a target speed of the motor is acquired, and a load torque of the motor is acquired; according to the target speed of the motor and the load torque of the motor, a response speed of the motor in a first mode is determined; the motor is controlled to accelerate or decelerate at the response speed; and only when a current speed of the motor reaches the target speed of the motor, a mode switching instruction is executed, that is, a control mode of the motor is switched from the first mode to a second mode, so that smooth switching of the control mode of the motor from the first mode to the second mode is realized. According to the scheme, the mode switching time point of the motor is dynamically adjusted according to the load torque and the target speed of the motor, smooth switching of the motor mode is realized, and the control precision and the control efficiency of the motor are improved.

Description

Technical Field

[0001] This invention belongs to the field of motor control technology, specifically relating to a method, device, servo drive device, and storage medium for switching motor control modes, and particularly to a method, device, servo drive device, and storage medium for fast switching of motor control modes in a servo drive device based on a state observer. Background Technology

[0002] With the rapid development of the servo drive field, single-axis servo drives have been widely used in various machining systems such as CNC composite machine tools, fully automatic servo screw tightening machines, winding machines, and polishing machines, with increasingly higher machining accuracy and efficiency. As users' machining requirements increase, single-axis servo drives are no longer limited to single-mode operation; the motors also need to be able to switch between two different control modes online. For example, CNC machine tools need to switch between speed mode and position mode, servo screw tightening machines need to switch between speed mode and torque mode, and polishing machines need to switch between position mode and torque mode, and so on.

[0003] In some solutions, the motor switches between two control modes either by switching directly or by decelerating to the target speed before switching. Both direct switching and deceleration-to-target-speed switching methods result in significant overshoot or speed jitter when the deceleration time is short, affecting the actual machining accuracy. In other solutions, the motor decelerates to near zero in one control mode before switching to the other. This method of decelerating to zero before switching affects machining efficiency.

[0004] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The purpose of this invention is to provide a method, apparatus, servo drive device, and storage medium for switching control modes of a motor. This addresses the problems of significant overshoot or speed fluctuations affecting control accuracy when switching between two control modes, either by directly switching or by decelerating to the target speed before switching. Furthermore, it addresses the issue of reduced control efficiency when decelerating to near zero before switching. The invention achieves a smooth transition by dynamically adjusting the switching time from the first mode (e.g., speed mode) to the second mode (e.g., position mode) based on the motor's load torque and target speed. This improves both the control accuracy and efficiency of the motor.

[0006] This invention provides a method for switching the control mode of a motor, wherein the control modes of the motor include a first mode and a second mode; the method includes: determining whether a mode switching command for the motor is received; the mode switching command is an instruction to indicate that the control mode of the motor needs to be switched from the first mode to the second mode; if the mode switching command is received, obtaining the target speed of the motor and the load torque of the motor; determining the response speed of the motor in the first mode based on the target speed and the load torque of the motor; controlling the motor to accelerate or decelerate according to the response speed so that the current speed of the motor reaches the target speed of the motor; when the current speed of the motor reaches the target speed of the motor, executing the mode switching command, that is, controlling the control mode of the motor to switch from the first mode to the second mode, thereby achieving a smooth switch of the control mode of the motor from the first mode to the second mode.

[0007] In some embodiments, obtaining the target speed of the motor includes: obtaining the position command of the motor; determining the target speed of the motor based on the position command of the motor; wherein, determining the target speed of the motor based on the position command of the motor includes: determining the target speed corresponding to the set position command that is the same as the position command of the motor in the set position command and the set target speed according to the correspondence between the set position command and the set target speed in the set correspondence as the target speed of the motor corresponding to the position command of the motor.

[0008] In some implementations, determining the response speed of the motor in the first mode based on the target speed of the motor and the load torque of the motor includes: calculating the torque change rate of the motor based on the target speed of the motor; and calculating the response speed of the motor in the first mode based on the torque change rate of the motor and the load torque of the motor.

[0009] In some embodiments, calculating the torque change rate of the motor based on the target speed of the motor includes: calculating the torque change rate of the motor using the following formula based on the target speed of the motor:

[0010]

[0011] Among them, sT e U is the rate of change of torque. dc i is the DC bus voltage. q Let L be the q-axis current. q R is the q-axis inductance, and R is the motor stator resistance. Let ψ be the target speed of the motor.f For rotor flux linkage, P n The number of pole pairs of the motor; and / or, based on the rate of change of the motor's torque and the load torque of the motor, calculating the response speed of the motor in the first mode, including: calculating the response speed of the motor in the first mode using the following formula based on the rate of change of the motor's torque and the load torque of the motor:

[0012]

[0013] Where, ω e T represents the response speed of the motor. e T is the electromagnetic torque output by the motor. l T is the load torque of the motor. emax The maximum electromagnetic torque of the motor when it operates in the first mode up to its response speed is given by J, where J is the moment of inertia of the motor, and sT is the maximum electromagnetic torque of the motor. e P is the rate of change of torque. n This represents the number of pole pairs of the motor. The target speed of the motor.

[0014] In some implementations, controlling the motor to accelerate or decelerate at the response speed to bring the current speed of the motor to the target speed of the motor includes: determining the ramp start speed for the motor to accelerate or decelerate at the response speed based on the speed command of the motor and the speed feedback value of the motor; using the response speed as the ramp end speed of the motor, controlling the motor to accelerate or decelerate at the rate of change of the motor's torque to bring the current speed of the motor to the target speed of the motor.

[0015] In conjunction with the above method, another aspect of the present invention provides a motor control mode switching device, wherein the motor control modes include: a first mode and a second mode; the motor control mode switching device includes: a control unit configured to determine whether a mode switching command for the motor is received; the motor mode switching command is an instruction indicating that the control mode of the motor needs to be switched from the first mode to the second mode; an acquisition unit configured to, if the motor mode switching command is received, acquire the target speed of the motor and acquire the load torque of the motor; the control unit is further configured to determine the response speed of the motor in the first mode based on the target speed of the motor and the load torque of the motor; the control unit is further configured to control the motor to accelerate or decelerate according to the response speed so that the current speed of the motor reaches the target speed of the motor; the control unit is further configured to execute the mode switching command when the current speed of the motor reaches the target speed of the motor, that is, to control the control mode of the motor to switch from the first mode to the second mode, thereby achieving a smooth switch of the motor control mode from the first mode to the second mode.

[0016] In some embodiments, the acquisition unit acquires the target speed of the motor by: acquiring the position command of the motor; and determining the target speed of the motor based on the position command of the motor. Specifically, determining the target speed of the motor based on the position command of the motor includes: determining the target speed corresponding to the set position command that is identical to the position command of the motor in the set position command and the set target speed based on the correspondence between the set position command and the set target speed.

[0017] In some implementations, the control unit determines the response speed of the motor in the first mode based on the target speed of the motor and the load torque of the motor, including: calculating the torque change rate of the motor based on the target speed of the motor; and calculating the response speed of the motor in the first mode based on the torque change rate of the motor and the load torque of the motor.

[0018] In some embodiments, the control unit calculates the torque change rate of the motor based on the target speed of the motor, including: calculating the torque change rate of the motor using the following formula based on the target speed of the motor:

[0019]

[0020] Among them, sT e U is the rate of change of torque. dci is the DC bus voltage. q Let L be the q-axis current. q R is the q-axis inductance, and R is the motor stator resistance. Let ψ be the target speed of the motor. f For rotor flux linkage, P n The number of pole pairs of the motor; and / or, the control unit calculates the response speed of the motor in the first mode based on the torque change rate of the motor and the load torque of the motor, including: calculating the response speed of the motor in the first mode using the following formula based on the torque change rate of the motor and the load torque of the motor:

[0021]

[0022] Where, ω e T represents the response speed of the motor. e T is the electromagnetic torque output by the motor. l T is the load torque of the motor. emax The maximum electromagnetic torque of the motor when it operates in the first mode up to its response speed is given by J, where J is the moment of inertia of the motor, and sT is the maximum electromagnetic torque of the motor. e P is the rate of change of torque. n This represents the number of pole pairs of the motor. The target speed of the motor.

[0023] In some embodiments, the control unit controls the motor to accelerate or decelerate at the response speed so that the current speed of the motor reaches the target speed of the motor, including: determining the ramp start speed for the motor to accelerate or decelerate at the response speed based on the speed command of the motor and the speed feedback value of the motor; using the response speed as the ramp end speed of the motor, controlling the motor to accelerate or decelerate at the rate of change of the motor's torque so that the current speed of the motor reaches the target speed of the motor.

[0024] In conjunction with the above-mentioned device, the present invention further provides a servo drive device, including: the motor control mode switching device described above.

[0025] In conjunction with the above method, the present invention further provides a storage medium comprising a stored program, wherein, when the program is executed, the device on which the storage medium is located executes the motor control mode switching method described above.

[0026] Therefore, the solution of the present invention determines the target speed at which the motor switches from a first mode (e.g., speed mode) to a second mode (e.g., position mode), matches the motor's torque change rate with the target speed, and then calculates the motor's response speed based on the torque change rate. Furthermore, based on the motor's response speed and the load torque observed by the load torque state observer, the switching point for the motor to switch from the first mode (e.g., speed mode) to the second mode (e.g., position mode) is determined, achieving a smooth switching of the motor from the first mode (e.g., speed mode) to the second mode (e.g., position mode). Thus, by dynamically adjusting the motor's mode switching time point according to the motor's load torque and target speed, smooth switching of the motor mode is achieved, improving the motor's control accuracy and efficiency.

[0027] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention.

[0028] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0029] Figure 1 This is a flowchart illustrating an embodiment of the motor control mode switching method of the present invention;

[0030] Figure 2 This is a flowchart illustrating an embodiment of the method of the present invention for determining the response speed of a motor in a first mode, such as a speed mode.

[0031] Figure 3 This is a flowchart illustrating an embodiment of the method of the present invention, which controls a motor to accelerate or decelerate according to a response speed.

[0032] Figure 4 This is a schematic diagram of a structure of an embodiment of the motor control mode switching device of the present invention;

[0033] Figure 5 A control mode switching curve diagram of an embodiment of a method for rapid control mode switching of a motor in a servo drive device based on a state observer;

[0034] Figure 6 This is a schematic diagram of the control mode switching process of an embodiment of a method for fast switching of motor control modes in a servo drive device based on a state observer;

[0035] Figure 7 This is a schematic diagram of an embodiment of a system for rapidly switching control modes of a motor in a servo drive device based on a state observer.

[0036] Referring to the accompanying drawings, the reference numerals in the embodiments of the present invention are as follows:

[0037] 102 - Acquisition unit; 104 - Control unit. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0039] The proposed solution involves determining the difference between the current speed before and the target speed after the switch. It then checks if this difference falls within a safe range before proceeding with the switch, thus achieving rapid switching. However, this method requires manually setting a safe switching range and considering the need to readjust the parameters under different load torque conditions. If the switching range is too small, the switching efficiency will be too low; if it is too large, speed fluctuations or overshoot may occur during the switch.

[0040] Considering that in various processing systems such as CNC composite machine tools, fully automatic servo screw tightening machines, winding machines, and polishing machines, when the motor switches between two different control modes online, both direct switching and deceleration to the target speed before switching can result in significant overshoot or speed jitter, affecting control accuracy; while decelerating to near zero before switching can affect control efficiency. Related solutions, which ensure the difference between the current speed before switching and the target speed after switching is within a safe range, can achieve rapid switching, but require manually setting a safe switching range and resetting the safe switching range parameters under different load torque conditions. If the switching range is too small, the switching efficiency is too low; if the switching range is too large, speed jitter or overshoot occurs during switching. This invention proposes a control mode switching scheme for motors in servo drive devices, specifically a rapid control mode switching scheme for motors in servo drive devices based on a state observer.

[0041] According to an embodiment of the present invention, a method for switching the control mode of a motor is provided, such as... Figure 1 The diagram shows a flowchart of an embodiment of the method of the present invention. The control modes of the motor include: a first mode and a second mode, where the first mode is a speed mode and the second mode is a position mode. The method for switching the control modes of the motor includes steps S110 to S150.

[0042] In step S110, it is determined whether a mode switching command for the motor has been received. The motor mode switching command is an instruction indicating that the control mode of the motor needs to be switched from the first mode to the second mode. The motor mode switching command is, in effect, the motor mode switching signal.

[0043] In step S120, if a mode switching command for the motor is received, the target speed of the motor and the load torque of the motor are obtained. Specifically, obtaining the load torque of the motor involves obtaining the load torque state observation value observed by the load torque state observer.

[0044] In some implementations, obtaining the target speed of the motor in step S120 includes: obtaining the position command of the motor, specifically obtaining the position command sent by the host computer, wherein the position command of the motor is specifically a pulse position command, which is a control command of the motor in the position loop; determining the target speed of the motor based on the position command of the motor; wherein determining the target speed of the motor based on the position command of the motor includes: determining the target speed of the motor corresponding to the set position command that is the same as the position command of the motor in the set position command according to the correspondence between the set position command and the set target speed.

[0045] Figure 6 This is a schematic diagram of the control mode switching process of an embodiment of a method for rapid switching of motor control modes in a servo drive device based on a state observer. Figure 6 As shown, the present invention provides a method for rapid switching of motor control modes in a servo drive device based on a state observer, comprising:

[0046] Step 1: The servo driver receives the motor control mode switching signal, and then executes Step 2.

[0047] Step 2: When the servo driver receives the motor control mode switching signal, the servo driver enters the switching process. The following steps are executed during the switching process.

[0048] Step 21: The servo driver calculates the position speed command based on the position command sent by the host computer, and uses the position speed command as the target speed, then proceeds to step 22. Here, the host computer refers to the motion controller and teach pendant; when the host computer needs to switch to position mode, it needs to send position commands.

[0049] In step S130, the response speed of the motor in the first mode is determined based on the target speed of the motor and the load torque of the motor. The response speed is the speed at which the motor can reach its target speed according to a set torque change rate.

[0050] In some implementations, the specific process of determining the response speed of the motor in the first mode based on the target speed of the motor and the load torque of the motor in step S130 is illustrated in the following exemplary description.

[0051] The following is combined Figure 2 The flowchart shown is a schematic diagram of an embodiment of the method of the present invention for determining the response speed of a motor in a first mode, such as a speed mode. The specific process of determining the response speed of the motor in the first mode, such as a speed mode, in step S130 is further explained, including steps S210 and S220.

[0052] Step S210: Calculate the torque change rate of the motor based on the target speed of the motor.

[0053] In some implementations, calculating the torque change rate of the motor based on the target speed of the motor in step S210 includes: calculating the torque change rate of the motor using the following formula based on the target speed of the motor:

[0054]

[0055] Among them, sT e U is the rate of change of torque. dc i is the DC bus voltage. q Let L be the q-axis current. q R is the q-axis inductance, and R is the motor stator resistance. Let ψ be the target speed of the motor. f For rotor flux linkage, P n This represents the number of pole pairs of the motor.

[0056] Step S220 calculates the response speed of the motor in the first mode based on the torque change rate of the motor and the load torque of the motor.

[0057] In some implementations, calculating the response speed of the motor in the first mode based on the torque change rate and the load torque of the motor in step S220 includes: calculating the response speed of the motor in the first mode using the following formula based on the torque change rate and the load torque of the motor:

[0058]

[0059] Where, ωe T represents the response speed of the motor. e T is the electromagnetic torque output by the motor. l T is the load torque of the motor. emax The maximum electromagnetic torque of the motor when it operates in the first mode up to its response speed is given by J, where J is the moment of inertia of the motor, and sT is the maximum electromagnetic torque of the motor. e P is the rate of change of torque. n This represents the number of pole pairs of the motor. The target speed of the motor.

[0060] like Figure 6 As shown, the method for rapid switching of motor control modes in a servo drive device based on a state observer, as described in the present invention, further includes:

[0061] Step 22: The servo driver calculates the torque change rate at the target speed based on the target speed, and then executes step 23.

[0062] Step 23: Obtain the load torque state observation value from the state observer, which is used as the motor's load torque. Calculate the response speed using the torque change rate at the target speed and the load torque, then proceed to step 24.

[0063] Step 24: After receiving the control mode switching signal, the servo driver starts executing the speed ramp processing module to reach the response speed, which is recorded as the current speed. Then, step 25 is executed.

[0064] Step 25: The servo driver uses both the calculated position speed command and the current speed as inputs to the speed PI controller. When the current speed obtained by the speed ramp processing module in step 24 is the same as the calculated position speed command, this is the mode switching point, and the control mode switching begins. The calculated position speed command is the target speed.

[0065] To further illustrate the implementation process of the present invention, the implementation process is described below with reference to some implementation examples. This embodiment proposes a method for rapid switching of control modes for servo drive devices based on a state observer. This method ensures smooth and rapid switching of control modes under different load torque conditions by matching the torque change rate of the target speed. Taking the speed mode-position mode switching method as an example, when the servo drive is running in speed mode, after receiving the control mode switching signal, the servo drive enters the switching process. The servo drive calculates the position speed command based on the position command sent by the host computer. The position speed command is the target speed of the switching process. The allowable value of the torque change rate is calculated based on the target speed. The speed difference during the mode switching process will cause the current value output by the speed loop PI controller to become very large, causing current surges to the motor and inverter. This embodiment uses i d The control scheme is 0, therefore the torque change rate is designed based on the q-axis bus voltage, using the following calculation formula:

[0066]

[0067] sT e =1.5P n ψ f si q (2).

[0068] In equations (1) and (2), s is the differential operator d / dt, U dc i is the DC bus voltage. q Let L be the q-axis current. q R is the q-axis inductance, and R is the motor stator resistance. ψ is the rotor's electric angular velocity, i.e., the target velocity. f For rotor flux linkage, P n sT represents the number of pole pairs of the motor. e This is the torque change rate. The torque change rate sT can be designed using equations (1) and (2). e Correspondence:

[0069]

[0070] Specifically, the position speed command is calculated based on the position command. This can be achieved by multiplying the position deviation by the proportional gain coefficient Kp within the program, according to the calculation method of the position loop P controller. The proportional gain coefficient Kp can be given according to the actual situation.

[0071] like Figure 5 As shown, the servo driver calculates the position speed command, which corresponds to the target speed at point C in the figure, based on the position command sent by the host computer. The torque change rate near point C can be calculated using equation (3). Figure 5As shown, considering the extreme case, the electromagnetic torque T is the maximum electromagnetic torque when the current surge caused by the speed difference between point A and point B reaches its maximum. emax At that time, the relationship between torque and velocity can be obtained from the equations of motion equilibrium:

[0072]

[0073] T e * (t)=T emax +sT e [tt C (5).

[0074]

[0075] By rearranging equations (4), (5), and (6), we can obtain the following relation:

[0076]

[0077] In equation (7), T e T is the electromagnetic torque output by the motor. l T is the load torque of the motor. emax Let J be the maximum electromagnetic torque reached from point A to point B, and let sT be the moment of inertia of the motor. e It is the differential of electromagnetic torque with respect to time, sT e P is the rate of change of torque. n This represents the number of pole pairs of the motor. The target speed at point C is given by the load torque T. l T can be obtained through an algorithmic observer. e * (t) represents the electromagnetic torque output by the motor at time t. In this embodiment, the load torque T of the motor is... l A linear extended state observer is used for observation. This linear extended state observer has a simple observation algorithm, fast response speed, and can reduce the phase lag of the motor control system. The response speed at point B can be finally obtained according to equation (7).

[0078] When the servo driver receives the mode switching signal, the speed (i.e., response speed) corresponding to point B can be calculated according to the above formula (7). The servo driver first performs acceleration and deceleration processing through the speed ramp processing module. In this embodiment, it needs to be accelerated to the response speed. The target speed is used as the input of the speed loop PI controller. The target speed will reach near point C with a specified torque change rate. When the speed corresponding to point C is equal to the target speed, the output electromagnetic torque will also just reach the load torque T of the motor. l Finally, the control mode switch is completed.

[0079] In step S140, the motor is controlled to accelerate or decelerate according to the response speed so that the current speed of the motor reaches the target speed of the motor, specifically, the current speed of the motor reaches the target speed of the motor at a set torque change rate.

[0080] In some embodiments, the specific process of controlling the motor to accelerate or decelerate at the response speed in step S140 so that the current speed of the motor reaches the target speed of the motor is described in the following exemplary description.

[0081] The following is combined Figure 3 The flowchart shown is a schematic diagram of an embodiment of the method of the present invention, which controls the motor to accelerate or decelerate according to the response speed. It further illustrates the specific process of controlling the motor to accelerate or decelerate according to the response speed in step S140, including steps S310 and S320.

[0082] Step S310: Determine the starting speed of the ramp for the motor to accelerate or decelerate according to the response speed based on the speed command of the motor and the speed feedback value of the motor.

[0083] Step S320: Using the response speed as the ramp endpoint speed of the motor, control the motor to accelerate or decelerate according to the torque change rate of the motor, so that the current speed of the motor reaches the target speed of the motor.

[0084] In step S150, when the current speed of the motor reaches the target speed of the motor, the mode switching command is executed, that is, the control mode of the motor is switched from the first mode to the second mode, so as to achieve a smooth switch of the control mode of the motor from the first mode to the second mode.

[0085] The present invention proposes a rapid switching scheme for servo drive equipment control modes based on a state observer. This scheme dynamically adjusts the switching time point under different load torque conditions by matching the torque change rate to the target speed, ensuring smooth and rapid switching between control modes. Specifically, in the present invention, the torque change rate can be designed based on the load torque and the target switching speed, and the response speed can be calculated. The response speed can reach the target speed with the designed torque change rate, thereby dynamically adjusting the switching time point according to the load torque and target speed, ensuring smooth and rapid switching between speed mode and position mode.

[0086] Figure 5 This is a control mode switching curve diagram of an embodiment of a method for rapid control mode switching of a motor in a servo drive device based on a state observer. Figure 5As shown, in the solution of this invention, the motor control mode achieves a smooth transition from speed mode to position mode through a switching process from point A to point B to point C. Point A represents speed mode; point A to point B represents the process of determining and reaching the response speed in speed mode; point B to point C represents the process after reaching the response speed in speed mode; point C is the mode switching point; and the mode transition occurs after point C.

[0087] Figure 7 This is a schematic diagram of an embodiment of a system for rapidly switching control modes of a motor in a servo drive device based on a state observer. Figure 7 As shown, the solution of the present invention, a system for rapidly switching the control mode of a motor in a servo drive device based on a state observer, corresponding to a method for rapidly switching the control mode of a motor in a servo drive device based on a state observer, has a position loop and a speed loop.

[0088] In the speed loop, the position pulse command is calculated by the position speed command calculation module to obtain the position speed command. The torque change rate calculation module calculates the torque change rate based on the position speed command. The load torque state observer, based on the motor's q-axis current feedback and motor speed feedback, obtains the motor's load torque state observation value, which serves as the motor's load torque. The response speed calculation module calculates the response speed based on the torque change rate and load torque. The speed command and speed feedback are passed through the speed loop comparator to output the ramp start speed. The response speed, as the ramp end speed, is input to the speed ramp processing module, which performs speed ramp processing to reach the response speed, which is recorded as the current speed. This process corresponds to... Figure 5 The process from point A to point B in the diagram.

[0089] The servo driver uses both the calculated position speed command and the current speed as inputs to the speed PI controller. When the current speed matches the calculated position speed command, it begins executing the control mode switching command, switching the execution mode switching module from the speed loop to the position loop. This process corresponds to... Figure 5 The process occurs after point B but before point C. During this process, before switching to the position loop, the calculated position-speed command is used as the speed setpoint for the speed loop. This speed setpoint is directly used as the input to the speed PI controller without being processed by the acceleration / deceleration module. This is a speed step, completed in a very short time. When the speed feedback matches this speed setpoint, the system switches to the position loop. This is a pre-switching process; switching to the position loop is equivalent to switching to position mode.

[0090] In the position loop, the position pulse command and displacement feedback value are compared and strengthened in the position loop before being passed to the position P controller, which outputs a position speed command. The execution mode switching module inputs this position speed command to the speed PI controller, and then the current loop controls the motor to run in position mode. This process corresponds to... Figure 5 The process after point C in the diagram, where point C is the point at which the speed mode switches to the position mode.

[0091] Thus, the solution of this invention, by automatically identifying load torque, ensures smooth operation without overshoot during the switching process, solving the problem of automatically adjusting the switching time point under different load torque conditions, reducing overshoot or speed jitter during control mode switching, ensuring smooth mode switching, and improving the efficiency of the mode switching process. Furthermore, the solution of this invention eliminates the need for users to manually set switching conditions, avoiding erroneous judgments.

[0092] The control mode switching method described in this invention is not limited to speed-position mode switching; with simple modifications, it can be extended to switching between other two different control modes. The mode switching method and conditions are as follows: the response speed is calculated based on the load torque and torque change rate; switching is executed when the target speed matches the position command. Thus, mode switching based on the load observer can dynamically adjust the timing of the switching based on changes in load torque, ensuring a fast and smooth transition.

[0093] The technical solution of this embodiment determines the target speed at which the motor switches from a first mode (e.g., speed mode) to a second mode (e.g., position mode). The motor's torque change rate is matched to the target speed, and the motor's response speed is calculated based on this torque change rate. Furthermore, based on the motor's response speed and the load torque observed by the load torque state observer, the switching point from the first mode (e.g., speed mode) to the second mode (e.g., position mode) is determined, achieving a smooth switch from the first mode (e.g., speed mode) to the second mode (e.g., position mode). Thus, by dynamically adjusting the motor's mode switching time based on the load torque and target speed, smooth motor mode switching is achieved, improving the motor's control accuracy and efficiency.

[0094] According to an embodiment of the present invention, a motor control mode switching device corresponding to the motor control mode switching method is also provided. See also Figure 4 The diagram shows a structural schematic of an embodiment of the device of the present invention. The motor control modes include: a first mode and a second mode, where the first mode is a speed mode and the second mode is a position mode. The motor control mode switching device includes: an acquisition unit 102 and a control unit 104.

[0095] The control unit 104 is configured to determine whether a mode switching command for the motor has been received. The motor mode switching command is an instruction indicating that the control mode of the motor needs to be switched from the first mode to the second mode. The motor mode switching command is the motor mode switching signal. The specific functions and processing of the control unit 104 are described in step S110.

[0096] The acquisition unit 102 is configured to, upon receiving a mode switching command from the motor, acquire the target speed of the motor and the load torque of the motor, specifically acquiring the load torque state observation value observed by the load torque state observer. The specific functions and processing of this acquisition unit 102 are described in step S120.

[0097] In some embodiments, the acquisition unit 102 acquires the target speed of the motor by: acquiring the position command of the motor, specifically acquiring the position command sent by the host computer, wherein the position command of the motor is specifically a pulse position command, which is a control command of the motor in the position loop; and then, determining the target speed of the motor based on the position command of the motor.

[0098] The acquisition unit 102 determines the target speed of the motor according to the position command of the motor, including: the acquisition unit 102 is further configured to determine the target speed of the motor corresponding to the position command that is the same as the position command of the motor in the correspondence between the set position command and the set target speed, according to the correspondence between the set position command and the set target speed.

[0099] Figure 6 This is a schematic diagram of the control mode switching process of an embodiment of a fast control mode switching device for a motor in a servo drive device based on a state observer. Figure 6 As shown, a fast control mode switching device for a motor in a servo drive device based on a state observer, according to the present invention, includes:

[0100] Step 1: The servo driver receives the motor control mode switching signal, and then executes Step 2.

[0101] Step 2: When the servo driver receives the motor control mode switching signal, the servo driver enters the switching process. The following steps are executed during the switching process.

[0102] Step 21: The servo driver calculates the position speed command based on the position command sent by the host computer, and uses the position speed command as the target speed, and then executes step 22.

[0103] The control unit 104 is further configured to determine the response speed of the motor in the first mode based on the target speed of the motor and the load torque of the motor. The response speed is the speed at which the motor can reach the target speed at a set torque change rate. The specific functions and processing of the control unit 104 are further described in step S130.

[0104] In some embodiments, the control unit 104 determines the response speed of the motor in the first mode based on the target speed of the motor and the load torque of the motor, including:

[0105] The control unit 104 is further configured to calculate the torque change rate of the motor based on the target speed of the motor. The specific functions and processing of the control unit 104 are further described in step S210.

[0106] In some embodiments, the control unit 104 calculates the torque change rate of the motor based on the target speed of the motor, including: the control unit 104 is further configured to calculate the torque change rate of the motor based on the target speed of the motor using the following formula:

[0107]

[0108] Among them, sT e U is the rate of change of torque. dc i is the DC bus voltage. q Let L be the q-axis current. q R is the q-axis inductance, and R is the motor stator resistance. Let ψ be the target speed of the motor. f For rotor flux linkage, P n This represents the number of pole pairs of the motor.

[0109] The control unit 104 is further configured to calculate the response speed of the motor in the first mode based on the torque change rate of the motor and the load torque of the motor. The specific functions and processing of the control unit 104 are further described in step S220.

[0110] In some embodiments, the control unit 104 calculates the response speed of the motor in the first mode based on the torque change rate of the motor and the load torque of the motor, including: the control unit 104 is further configured to calculate the response speed of the motor in the first mode using the following formula based on the torque change rate of the motor and the load torque of the motor:

[0111]

[0112] Where, ωe T represents the response speed of the motor. e T is the electromagnetic torque output by the motor. l T is the load torque of the motor. emax The maximum electromagnetic torque of the motor when it operates in the first mode up to its response speed is given by J, where J is the moment of inertia of the motor, and sT is the maximum electromagnetic torque of the motor. e P is the rate of change of torque. n This represents the number of pole pairs of the motor. The target speed of the motor.

[0113] like Figure 6 As shown, the fast switching device for motor control mode in a servo drive device based on a state observer according to the present invention further includes:

[0114] Step 22: The servo driver calculates the torque change rate at the target speed based on the target speed, and then executes step 23.

[0115] Step 23: Obtain the load torque state observation value from the state observer, which is used as the motor's load torque. Calculate the response speed using the torque change rate at the target speed and the load torque, then proceed to step 24.

[0116] Step 24: After receiving the control mode switching signal, the servo driver starts executing the speed ramp processing module to reach the response speed, which is recorded as the current speed. Then, step 25 is executed.

[0117] Step 25: The servo driver uses both the calculated position speed command and the current speed as inputs to the speed PI controller. When the current speed obtained by the speed ramp processing module in step 24 is the same as the calculated position speed command, this is the mode switching point, and the control mode switching begins. The calculated position speed command is the target speed.

[0118] To further illustrate the implementation process of the present invention, the implementation process is described below with reference to some implementation examples. This embodiment proposes a servo drive device control mode fast switching device based on a state observer, which ensures smooth and rapid switching of control modes under different load torque conditions by matching the torque change rate of the target speed. Taking the speed mode-position mode switching method as an example, when the servo drive is running in speed mode, after receiving the control mode switching signal, the servo drive enters the switching process. The servo drive calculates the position speed command according to the position command sent by the host computer. The position speed command is the target speed of the switching process. The allowable value of the torque change rate is calculated based on the target speed. The speed difference during the mode switching process will cause the current value output by the speed loop PI controller to become very large, causing current surges to the motor and inverter. This embodiment uses i d The control scheme is 0, therefore the torque change rate is designed based on the q-axis bus voltage, using the following calculation formula:

[0119]

[0120] sT e =1.5P n ψ f si q (2).

[0121] In equations (1) and (2), s is the differential operator d / dt, U dc i is the DC bus voltage. q Let L be the q-axis current. q R is the q-axis inductance, and R is the motor stator resistance. ψ is the rotor's electric angular velocity, i.e., the target velocity. f For rotor flux linkage, P n sT represents the number of pole pairs of the motor. e This is the torque change rate. The torque change rate sT can be designed using equations (1) and (2). e Correspondence:

[0122]

[0123] like Figure 5 As shown, the servo driver calculates the position speed command, which corresponds to the target speed at point C in the figure, based on the position command sent by the host computer. The torque change rate near point C can be calculated using equation (3). Figure 5 As shown, considering the extreme case, the electromagnetic torque T is the maximum electromagnetic torque when the current surge caused by the speed difference between point A and point B reaches its maximum. emax At that time, the relationship between torque and velocity can be obtained from the equations of motion equilibrium:

[0124]

[0125] T e * (t)=T e max +sT e [tt C (5).

[0126]

[0127] By rearranging equations (4), (5), and (6), we can obtain the following relation:

[0128]

[0129] In equation (7), T e T is the electromagnetic torque output by the motor. l T is the load torque of the motor. emax Let J be the maximum electromagnetic torque reached from point A to point B, and let sT be the moment of inertia of the motor. e It is the differential of electromagnetic torque with respect to time, sT e P is the rate of change of torque. n This represents the number of pole pairs of the motor. The target speed at point C is given by the load torque T. l In this embodiment, the load torque T of the motor can be obtained through an algorithmic observer. l A linear extended state observer is used for observation. This linear extended state observer has a simple observation algorithm, fast response speed, and can reduce the phase lag of the motor control system. The response speed at point B can be finally obtained according to equation (7).

[0130] When the servo driver receives the mode switching signal, the speed (i.e., response speed) corresponding to point B can be calculated according to the above formula (7). The servo driver first performs acceleration and deceleration processing through the speed ramp processing module. In this embodiment, it needs to be accelerated to the response speed. The target speed is used as the input of the speed loop PI controller. The target speed will reach near point C with a specified torque change rate. When the speed corresponding to point C is equal to the target speed, the output electromagnetic torque will also just reach the load torque T of the motor. l Finally, the control mode switch is completed.

[0131] The control unit 104 is further configured to control the motor to accelerate or decelerate at the response speed, so that the current speed of the motor reaches the target speed of the motor, specifically, to make the current speed of the motor reach the target speed of the motor at a set torque change rate. The specific functions and processing of the control unit 104 are further described in step S140.

[0132] In some embodiments, the control unit 104 controls the motor to accelerate or decelerate according to the response speed so that the current speed of the motor reaches the target speed of the motor, including:

[0133] The control unit 104 is further configured to determine the ramp starting speed at which the motor accelerates or decelerates according to the response speed, based on the motor's speed command and the motor's speed feedback value. The specific functions and processing of this control unit 104 are further described in step S310.

[0134] The control unit 104 is further configured to use the response speed as the ramp-end speed of the motor, and control the motor to accelerate or decelerate according to the motor's torque change rate, so that the motor's current speed reaches the motor's target speed. The specific functions and processing of this control unit 104 are further described in step S320.

[0135] The control unit 104 is further configured to execute the mode switching command when the current speed of the motor reaches the target speed of the motor, that is, to control the motor's control mode to switch from the first mode to the second mode, thereby achieving a smooth switch of the motor's control mode from the first mode to the second mode. The specific functions and processing of this control unit 104 are further described in step S150.

[0136] The present invention proposes a rapid switching scheme for servo drive equipment control modes based on a state observer. This scheme dynamically adjusts the switching time point under different load torque conditions by matching the torque change rate to the target speed, ensuring smooth and rapid switching between control modes. Specifically, in the present invention, the torque change rate can be designed based on the load torque and the target switching speed, and the response speed can be calculated. The response speed can reach the target speed with the designed torque change rate, thereby dynamically adjusting the switching time point according to the load torque and target speed, ensuring smooth and rapid switching between speed mode and position mode.

[0137] Figure 5 This is a control mode switching curve diagram of an embodiment of a fast control mode switching device for a motor in a servo drive device based on a state observer. Figure 5 As shown, in the solution of this invention, the motor control mode achieves a smooth transition from speed mode to position mode through a switching process from point A to point B to point C. Point A represents speed mode; point A to point B represents the process of determining and reaching the response speed in speed mode; point B to point C represents the process after reaching the response speed in speed mode; point C is the mode switching point; and the mode transition occurs after point C.

[0138] Figure 7This is a schematic diagram of an embodiment of a system for rapidly switching control modes of a motor in a servo drive device based on a state observer. Figure 7 As shown, in the present invention, the control mode fast switching system for a motor in a servo drive device based on a state observer, corresponding to the control mode fast switching device for a motor in a servo drive device based on a state observer, has a position loop and a speed loop.

[0139] In the speed loop, the position pulse command is calculated by the position speed command calculation module to obtain the position speed command. The torque change rate calculation module calculates the torque change rate based on the position speed command. The load torque state observer, based on the motor's q-axis current feedback and motor speed feedback, obtains the motor's load torque state observation value, which serves as the motor's load torque. The response speed calculation module calculates the response speed based on the torque change rate and load torque. The speed command and speed feedback are passed through the speed loop comparator to output the ramp start speed. The response speed, as the ramp end speed, is input to the speed ramp processing module, which performs speed ramp processing to reach the response speed, which is recorded as the current speed. This process corresponds to... Figure 5 The process from point A to point B in the diagram.

[0140] The servo driver uses both the calculated position speed command and the current speed as inputs to the speed PI controller. When the current speed matches the calculated position speed command, it begins executing the control mode switching command, switching the execution mode switching module from the speed loop to the position loop. This process corresponds to... Figure 5 The process after point B but before point C.

[0141] In the position loop, the position pulse command and displacement feedback value are compared and strengthened in the position loop before being passed to the position P controller, which outputs a position speed command. The execution mode switching module inputs this position speed command to the speed PI controller, and then the current loop controls the motor to run in position mode. This process corresponds to... Figure 5 The process after point C in the diagram, where point C is the point at which the speed mode switches to the position mode.

[0142] Thus, the solution of this invention, by automatically identifying load torque, ensures smooth operation without overshoot during the switching process, solving the problem of automatically adjusting the switching time point under different load torque conditions, reducing overshoot or speed jitter during control mode switching, ensuring smooth mode switching, and improving the efficiency of the mode switching process. Furthermore, the solution of this invention eliminates the need for users to manually set switching conditions, avoiding erroneous judgments.

[0143] The control mode switching device described in this invention is not limited to speed-position mode switching; with simple modifications, it can be extended to switch between two other different control modes. The mode switching method and conditions are as follows: the response speed is calculated based on the load torque and torque change rate; switching is executed when the target speed matches the position command. Thus, mode switching based on the load observer can dynamically adjust the timing of the switching based on changes in load torque, ensuring a fast and smooth transition.

[0144] Since the processing and functions implemented by the device in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in the description of this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0145] By employing the technical solution of this invention, the target speed for the motor to switch from a first mode (e.g., speed mode) to a second mode (e.g., position mode) is determined. The motor's torque change rate is matched according to the target speed, and then the motor's response speed is calculated based on the motor's torque change rate. Furthermore, based on the motor's response speed and combined with the load torque observed by the load torque state observer, the switching point for the motor to switch from the first mode (e.g., speed mode) to the second mode (e.g., position mode) is determined, thereby achieving a smooth switching of the motor from the first mode (e.g., speed mode) to the second mode (e.g., position mode), reducing overshoot or speed jitter generated during the control mode switching process, ensuring smooth mode switching, and improving the efficiency of the mode switching process.

[0146] According to an embodiment of the present invention, a servo drive device corresponding to a motor control mode switching device is also provided. This servo drive device may include the motor control mode switching device described above.

[0147] Since the processing and functions implemented by the servo drive device in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned device, any details not covered in the description of this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0148] By employing the technical solution of this invention, the target speed for the motor to switch from a first mode (such as speed mode) to a second mode (such as position mode) is determined. The motor's torque change rate is matched according to the target speed, and then the motor's response speed is calculated based on the motor's torque change rate. Furthermore, based on the motor's response speed and combined with the load torque observed by the load torque state observer, the switching point for the motor to switch from the first mode (such as speed mode) to the second mode (such as position mode) is determined, achieving a smooth switching of the motor from the first mode (such as speed mode) to the second mode (such as position mode). This results in high switching efficiency and eliminates the need for users to manually set switching conditions, thus avoiding erroneous judgments.

[0149] According to an embodiment of the present invention, a storage medium corresponding to a motor control mode switching method is also provided. The storage medium includes a stored program, wherein the program controls the device where the storage medium is located to execute the motor control mode switching method described above when it is running.

[0150] Since the processing and functions implemented by the storage medium in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0151] By employing the technical solution of this invention, the target speed at which the motor switches from a first mode (e.g., speed mode) to a second mode (e.g., position mode) is determined. The motor's torque change rate is matched to the target speed, and the motor's response speed is calculated based on the torque change rate. Furthermore, based on the motor's response speed and the load torque observed by the load torque state observer, the switching point from the first mode (e.g., speed mode) to the second mode (e.g., position mode) is determined, achieving a smooth switching of the motor from the first mode (e.g., speed mode) to the second mode (e.g., position mode). This ensures the control accuracy and efficiency of the motor, thereby guaranteeing the processing accuracy and efficiency of the servo drive equipment where the motor is located.

[0152] In summary, it is readily understood by those skilled in the art that, without conflict, the aforementioned advantageous methods can be freely combined and superimposed.

[0153] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A control mode switching method of an electric motor, characterized by, The control mode of the motor includes a first mode and a second mode; and a control mode switching method of the motor includes: determining whether a mode switching instruction of the motor is received; the mode switching instruction of the motor is an instruction for indicating that the control mode of the motor needs to be switched from the first mode to the second mode; if the mode switching instruction of the motor is received, obtaining a target speed of the motor and a load torque of the motor; according to the target speed of the motor, calculating a torque change rate of the motor by using the following formula: ； wherein, is a torque rate of change, is a DC bus voltage, is a q-axis current, is a q-axis inductance, is a motor stator resistance, is a target speed of the motor, is a rotor flux linkage, is a number of motor pole pairs; according to the torque change rate of the motor and the load torque of the motor, calculating a response speed of the motor in the first mode by using the following formula: ； wherein, ω e is a response speed of the motor, T e is an electromagnetic torque output by the motor, is a load torque of the motor, is a maximum electromagnetic torque of the motor when the motor is running in the first mode to the response speed of the motor, J is a motor moment of inertia, is a torque change rate, is a motor pole pair number, is a target speed of the motor; controlling the motor to accelerate or decelerate at the response speed, so that a current speed of the motor reaches the target speed of the motor; in a case where the current speed of the motor reaches the target speed of the motor, executing the mode switching instruction, that is, controlling the control mode of the motor to be switched from the first mode to the second mode, to realize smooth switching of the control mode of the motor from the first mode to the second mode.

2. The control mode switching method of an electric motor according to claim 1, characterized by, obtaining the target speed of the motor includes: obtaining a position instruction of the motor; determining the target speed of the motor according to the position instruction of the motor; wherein determining the target speed of the motor according to the position instruction of the motor includes: according to a corresponding relationship between a set position instruction and a set target speed, determining a set target speed corresponding to a set position instruction same as the position instruction of the motor in the corresponding relationship as the target speed of the motor corresponding to the position instruction of the motor.

3. The control mode switching method of an electric motor according to claim 1, characterized by, controlling the motor to accelerate or decelerate at the response speed, so that the current speed of the motor reaches the target speed of the motor, includes: determining a ramp start speed at which the motor accelerates or decelerates at the response speed according to the speed instruction of the motor and a speed feedback value of the motor; controlling the motor to accelerate or decelerate at the torque change rate of the motor, so that the current speed of the motor reaches the target speed of the motor, with the response speed as a ramp end speed of the motor.

4. A control mode switching device of an electric motor which implements control mode switching of the electric motor by a control mode switching method of the electric motor as claimed in claim 1, characterized by The control mode of the motor includes a first mode and a second mode; and a control mode switching device of the motor includes: a control unit configured to determine whether a mode switching instruction of the motor is received; the mode switching instruction of the motor is an instruction for indicating that the control mode of the motor needs to be switched from the first mode to the second mode; an obtaining unit configured to, if the mode switching instruction of the motor is received, obtain a target speed of the motor and a load torque of the motor; the control unit is further configured to determine a response speed of the motor in the first mode according to the target speed of the motor and the load torque of the motor; the control unit is further configured to control the motor to accelerate or decelerate at the response speed, so that a current speed of the motor reaches the target speed of the motor; The control unit is further configured to execute the mode switching instruction in a case where the current speed of the motor reaches the target speed of the motor, that is, control the control mode of the motor to switch from the first mode to the second mode, to achieve smooth switching of the control mode of the motor from the first mode to the second mode.

5. The control mode switching apparatus of the electric motor according to claim 4, characterized by The obtaining unit obtains the target speed of the motor, including: obtaining a position instruction of the motor; determining the target speed of the motor according to the position instruction of the motor; wherein determining the target speed of the motor according to the position instruction of the motor includes: determining, according to a correspondence between a set position instruction and a set target speed, a set target speed corresponding to a set position instruction identical to the position instruction of the motor in the correspondence as the target speed of the motor corresponding to the position instruction of the motor.

6. The control mode switching apparatus of the electric motor according to claim 4 or 5, characterized by The control unit determines the response speed of the motor in the first mode according to the target speed of the motor and the load torque of the motor, including: calculating the torque change rate of the motor according to the target speed of the motor; calculating the response speed of the motor in the first mode according to the torque change rate of the motor and the load torque of the motor.

7. The control mode switching apparatus of the electric motor according to claim 6, characterized by wherein The control unit calculates the torque change rate of the motor according to the target speed of the motor, including: calculating the torque change rate of the motor according to the target speed of the motor using the following formula: ； wherein, is a torque rate of change, is a DC bus voltage, is a q-axis current, is a q-axis inductance, is a motor stator resistance, is a target speed of the motor, is a rotor flux linkage, is a number of motor pole pairs; and / or The control unit calculates the response speed of the motor in the first mode according to the torque change rate of the motor and the load torque of the motor, including: calculating the response speed of the motor in the first mode according to the torque change rate of the motor and the load torque of the motor using the following formula: ； wherein, ω e is a response speed of the motor, T e is an electromagnetic torque output by the motor, is a load torque of the motor, is a maximum electromagnetic torque of the motor when the motor is running in the first mode to the response speed of the motor, J is a motor moment of inertia, is a torque change rate, is a motor pole pair number, is a target speed of the motor.

8. The control mode switching apparatus of the electric motor according to claim 6, characterized by The control unit controls the motor to accelerate or decelerate at the response speed to make the current speed of the motor reach the target speed of the motor, including: determining a ramp start speed at which the motor accelerates or decelerates at the response speed according to the speed instruction of the motor and the speed feedback value of the motor; controlling the motor to accelerate or decelerate at the torque change rate of the motor with the response speed as a ramp end speed of the motor to make the current speed of the motor reach the target speed of the motor.

9. A servo drive apparatus characterized by comprising: including: The motor control mode switching device according to any one of claims 4 to 8.

10. A storage medium, characterized by The storage medium includes a stored program, wherein when the program runs, the device where the storage medium is located executes the motor control mode switching method according to any one of claims 1 to 3.

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