Control method, control device, control system and medium for electromagnetic clutch

Abstract

This invention discloses a control method, control device, control system, and medium for an electromagnetic clutch, belonging to the field of vehicle control technology. The method includes: dividing the control state of the electromagnetic clutch into four states: disengagement, engagement, disengagement in progress, and engagement in progress; switching to the engagement in progress state upon receiving an engagement command, employing different PWM control strategies for different stages; during the idle travel stage, dynamically calculating the electromagnetic engagement force based on the Maxwell electromagnetic attraction force physical model and real-time feedback of the current value and air gap, combined with the return device's spring force for closed-loop PWM control; switching to disengagement control upon receiving a disengagement command during engagement, and switching to engagement control upon receiving an engagement command during disengagement. Through four-state refined segmented control and real-time PWM calculation based on a physical model, combined with a state interruption jump mechanism, the aim is to reduce engagement impact, shorten response time, and reduce holding current.

Description

Technical Field

[0001] This invention relates to a control method, control device, control system, and medium for an electromagnetic clutch, belonging to the field of vehicle control technology. Background Technology

[0002] Hybrid systems in new energy vehicles can operate in different modes, primarily depending on the coordination between the electric motor and the engine within the hybrid system. The electromagnetic clutch is a core component that enables engine engagement and power transmission, placing high demands on overall vehicle performance and the coordinated control of its components.

[0003] As the closest prior art, published patent application CN119099583A proposes a method, device, equipment, and medium for disengaging an electromagnetic clutch. This method acquires vehicle parameter information when the electromagnetic clutch is in a rigid connection to determine if there is a risk of engine stalling. If a risk exists, it controls the electromagnetic clutch to disengage from the engine. Publication CN119641819A proposes a control method, device, equipment, and medium for an electromagnetic clutch, focusing on engaging or disengaging the clutch after adjusting the engine to optimal fuel consumption conditions. Furthermore, pulse width modulation control for regulating the excitation current of an electromagnetic clutch has been disclosed, and Maxwell's electromagnetic attraction force formula for offline clutch design calculations has also been disclosed.

[0004] However, the aforementioned existing technologies still have the following shortcomings: Firstly, existing control schemes coarsely classify the control states of electromagnetic clutches, typically only distinguishing between engagement and disengagement, without further subdividing the states into four stages—disengagement, engagement, disengagement in progress, and engagement in progress—based on the actual clutch movement. Particularly during engagement, the different control requirements of the idle and non-idle travel stages are not differentiated. During the idle travel stage, the return mechanism experiences significant spring force, requiring precise force balance control; during the non-idle travel stage, the spring force has largely dissipated, necessitating a rapid response. This lack of distinction makes it difficult to simultaneously achieve smooth engagement and fast response.

[0005] Secondly, existing pulse width modulation (PWM) control schemes often rely on empirical calibration or simple table lookups to determine the PWM duty cycle, failing to fully consider the coupling effects of multiple physical parameters such as clutch real-time position, return device spring force, air gap, effective magnetic area, and coil turns. Although Maxwell's electromagnetic attraction force formula has been applied in offline clutch design, it has never been embedded in the real-time control loop of the controller for online PWM calculation, resulting in insufficient control accuracy and frequent problems such as large engagement shocks and incomplete disengagement.

[0006] Third, existing control methods are mostly unidirectional sequential execution. When the clutch receives a disengagement command during engagement or a disengagement command during engagement, there is a lack of smooth interruption and jump mechanism, which may lead to control conflicts or execution delays.

[0007] Fourth, the maintenance control after clutch engagement often uses a fixed pulse width modulation value, without determining the minimum pulse width modulation threshold required to maintain engagement through boundary measurement, resulting in unnecessary energy consumption increase or unreliable maintenance.

[0008] Therefore, there is an urgent need for an electromagnetic clutch control method, control device, control system, and medium that can accurately calculate the pulse width modulation control quantity based on multiple physical parameters such as the real-time position of the clutch, the spring force of the return device, and the air gap, and perform segmented control of the engagement process during idle / non-idle strokes, while also having the ability to jump to the state interruption. Summary of the Invention

[0009] To address the aforementioned technical problems, this invention provides a control method, control device, control system, and medium for an electromagnetic clutch. These methods achieve the following technical effects: finely dividing the control state of the electromagnetic clutch into four states; performing segmented control of idle / non-idle travel based on real-time position during engagement; performing real-time pulse width modulation calculation and closed-loop control based on the Maxwell electromagnetic attraction force physical model; and possessing bidirectional interruption and jump capability for engagement / disengagement.

[0010] To address the aforementioned technical problems, this invention provides a control method for an electromagnetic clutch, applied to hybrid vehicles, executed by a controller, the method comprising: The control states of the electromagnetic clutch are divided into disengagement state, engagement state, disengagement state, and engagement state. When a engagement command is received, the electromagnetic clutch is controlled to switch from the disengaged state to the engaged state. In the engaged state, the real-time position of the electromagnetic clutch is used to determine whether it is in the no-travel stage or the non-no-travel stage. Different pulse width modulation control strategies are used for different stages. During the idle travel phase, the electromagnetic attraction force is dynamically calculated based on the real-time feedback current value and air gap amount according to the electromagnetic attraction force physical model, and closed-loop pulse width modulation control is performed in combination with the spring force of the return device. If a separation command is received while the device is in the combined state, the system will switch to the separation state to perform separation control; if a combination command is received while the device is in the separation state, the system will switch to the combination state to perform combination control.

[0011] Preferably, the disengaged state is the state where the electromagnetic clutch is in a fully disengaged position, the engaged state is the state where the electromagnetic clutch is in a fully engaged position, the disengaged state is the transitional state of the electromagnetic clutch moving from the engaged state to the disengaged state, and the engaged state is the transitional state of the electromagnetic clutch moving from the disengaged state to the engaged state; the idle travel stage is the stage where the real-time position is between the disengaged position and the end of the idle travel, and the non-idle travel stage is the stage where the real-time position is between the end of the idle travel and the engaged position.

[0012] Preferably, the physical model of the electromagnetic attraction force is the Maxwell electromagnetic attraction force model, in which the electromagnetic attraction force is directly proportional to the square of the number of coil turns, the square of the current, and the effective magnetic area, and inversely proportional to the square of the air gap. The pulse width modulation control dynamically calculates the target electromagnetic attraction force based on the real-time feedback current value and air gap, and performs closed-loop adjustment based on the resultant force of the target electromagnetic attraction force and the spring force of the return device.

[0013] Preferably, the pulse width modulation value during the idle travel phase is determined by a two-dimensional linear interpolation method, and the interpolation calculation is performed in a pre-calibrated position-time-pulse width modulation value calibration table based on the current position and target combination time.

[0014] Preferably, the step of switching to the separation state to perform separation control includes: performing torque reduction control on the power source; when the input torque is less than a preset threshold, setting the pulse width modulation output to zero, reducing the coil current to zero, and achieving separation through the spring force of the return device.

[0015] Preferably, the method further includes a step of determining the minimum pulse width modulation threshold for maintaining engagement: driving the coil in a manner that gradually decreases the pulse width modulation value, monitoring the clutch position signal, recording the current pulse width modulation value when the clutch position signal indicates that the clutch begins to deviate from the engagement position, and determining the minimum pulse width modulation threshold for maintaining engagement based on the current pulse width modulation value.

[0016] Preferably, the method further includes: during the coupling process, real-time monitoring of the input shaft speed and the output shaft speed, calculating the speed difference, determining that the coupling is complete when the speed difference is less than a preset threshold, and switching the coupling state to the coupling state.

[0017] The present invention also provides an electromagnetic clutch control device, comprising: an electromagnetic clutch assembly including a clutch coil, a clutch actuator, and a return device, wherein when the clutch coil is energized, it generates an electromagnetic force to drive the clutch actuator to move in the engagement direction against the elastic force of the return device, and the return device is used to drive the clutch actuator to move in the disengagement direction when the clutch coil is de-energized; a signal detection device including a current sensor for sampling the current of the clutch coil, a speed sensor for detecting the rotational speeds of the clutch front and rear ends, and a position sensor for detecting the real-time position of the clutch actuator; a control unit connected to the signal detection device, receiving control commands and detection signals from the signal detection device, the control unit being configured to perform the method described in any of the above embodiments; and a power drive circuit connected to the control unit and the clutch coil, controlling the power supply to the clutch coil according to a pulse width modulation signal output by the control unit.

[0018] The present invention also provides an electromagnetic clutch control system, comprising: an electromagnetic clutch assembly including a clutch coil, a clutch actuator, and a return device; a signal detection device including a current sensor for sampling the coil current and a position sensor for detecting the real-time position of the clutch; a control unit for receiving control commands and detection signals from the signal detection device, the control unit being configured to perform the method described in any of the above embodiments; and a power drive circuit for controlling the power supply to the clutch coil according to a pulse width modulation signal output by the control unit.

[0019] The present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method described in any of the preceding claims.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: By subdividing the clutch state into four stages—disengagement, engagement, disengagement, and engagement—and further distinguishing the engagement process into a free travel stage and a non-free travel stage, refined control of the entire clutch engagement / disengagement process is achieved, improving engagement smoothness and response speed. By introducing multiple physical parameters such as clutch real-time position, return device deformation, air gap, effective magnetic area, and number of coil turns, the pulse width modulation value is accurately calculated and closed-loop control is performed based on Maxwell's electromagnetic attraction force formula, which significantly improves control accuracy and adaptability compared to empirical calibration schemes. By switching to separation control when a separation request is detected during the bonding process and switching to bonding control when a bonding request is detected during the bonding process, flexible switching of control states is achieved, avoiding control conflicts and execution delays. The minimum pulse width modulation value required to maintain the bond is determined by boundary measurement and used as the control threshold. This minimizes energy consumption and reduces the holding current while ensuring bond reliability. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the electromagnetic clutch control system according to one embodiment of the present invention; Figure 2 This is a flowchart illustrating an embodiment of the electromagnetic clutch control method of the present invention. Figure 3 This is a schematic diagram of a four-state machine transition according to one embodiment of the present invention. Detailed Implementation

[0023] Some embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In describing some embodiments of the present invention, detailed descriptions of relevant known configurations or functions will be omitted when it is determined that such detailed descriptions would hinder understanding of exemplary embodiments of the present invention.

[0024] In describing the constituent components of some embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc., may be used. These terms are used only to distinguish constituent components from other constituent components, and do not limit the nature, order, or sequence of the constituent components. Furthermore, unless otherwise specified in the specification, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0025] Before describing the invention in detail, several key terms used in the invention will be defined to facilitate understanding of the invention.

[0026] An "electromagnetic clutch" is a device that uses electromagnetic principles to control the engagement or disengagement of two rotating parts in a mechanical transmission system. It mainly includes a clutch coil, clutch actuator (armature / friction disc), and return device (return spring).

[0027] "Activated state" refers to the state in which the driving and driven parts of an electromagnetic clutch are fully engaged and can transmit power torque.

[0028] "Disengaged state" refers to the state in which the driving part and driven part of the electromagnetic clutch are completely disengaged and cannot transmit power torque.

[0029] "In engagement state" refers to the transitional state of the electromagnetic clutch from the disengaged state to the engaged state.

[0030] "Disengagement state" refers to the transitional state of the electromagnetic clutch from the engaged state to the disengaged state.

[0031] The "no-travel phase" refers to the period between the start of the electromagnetic clutch's movement from the disengaged position and the end of the no-travel phase. During this phase, the return device experiences large deformation and significant elasticity, requiring precise force balance control.

[0032] The "non-no-travel phase" refers to the stage between the end of the no-travel phase and the fully engaged position of the electromagnetic clutch. During this phase, the return mechanism has basically released its spring force and requires a rapid response to achieve quick engagement.

[0033] "Air gap" refers to the distance between the air gap between the electromagnetic clutch coil and the armature. It changes with the clutch position and directly affects the magnitude of the electromagnetic attraction force.

[0034] "Effective magnetic area" refers to the effective cross-sectional area through which the magnetic flux passes in the magnetic circuit of an electromagnetic clutch, which affects the calculation of the electromagnetic attraction force.

[0035] like Figure 1 As shown, the electromagnetic clutch control system provided in this embodiment of the invention includes an electromagnetic clutch assembly, a signal detection device, a control unit, and a power drive circuit.

[0036] The electromagnetic clutch assembly includes a clutch coil, a clutch actuator, and a return mechanism. When energized, the clutch coil generates an electromagnetic field, driving the clutch actuator to overcome the elastic force of the return mechanism and move in the engagement direction. The clutch actuator can be a separate structure of the armature and friction disc or an integrated structure; those skilled in the art can choose a suitable structural form according to the specific application scenario, and this invention does not impose any limitations on this. The return mechanism can employ a helical spring, a disc spring, or other elastic return mechanism; the relationship between its elastic force characteristics and deformation can be obtained through bench calibration.

[0037] The signal detection device includes a current sensor, a speed sensor, and a position sensor. The current sensor samples the current in the clutch coil; its range and accuracy can be selected based on the coil's rated current and accuracy requirements, which is not limited in this invention. Speed ​​sensors are respectively located at the front and rear ends of the clutch and are used to detect the input shaft speed and output shaft speed. The position sensor detects the real-time position of the clutch actuator; it can be a Hall effect position sensor, a magnetoresistive position sensor, or an inductive position sensor, and the specific type of sensor is not limited in this invention.

[0038] The control unit receives control commands from the vehicle controller or transmission control unit, as well as detection signals from the signal detection device, performs comprehensive calculations, and outputs a pulse width modulation control signal. The control unit can be integrated into the hybrid vehicle controller or transmission control unit, or it can be set up independently. Those skilled in the art should understand that the specific implementation of the control unit can be selected according to the vehicle's electronic and electrical architecture, and this invention does not limit this.

[0039] The power drive circuit controls the on / off frequency of the clutch coil based on the pulse width modulation signal output by the control unit, thereby regulating the coil current. The power drive circuit can employ an H-bridge circuit composed of a high-side switch and a low-side switch, or it can use a single-transistor drive circuit or an integrated drive chip solution. This invention does not limit the specific topology of the power drive circuit.

[0040] like Figure 2 As shown, this embodiment also provides an electromagnetic clutch control method, the specific steps of which include: Step S1 divides the control state of the electromagnetic clutch into disengagement state, engagement state, disengagement in progress state, and engagement in progress state. For example... Figure 3 As shown, the transition relationship between the four states is as follows: after receiving the combination command, the separation state enters the combination state; after the combination is completed, the combination state enters the combination state; after receiving the separation command, the combination state enters the separation state; and after the separation is completed, the separation state enters the separation state.

[0041] Step S2: Upon receiving an engagement command, the electromagnetic clutch is switched from the disengaged state to the engaged state. In the engaged state, the real-time position of the clutch determines whether it is in the idle travel phase or the non-idle travel phase. Different pulse width modulation control strategies are used for different phases. The idle travel phase is when the real-time position is between the disengaged position and the end of the idle travel phase, while the non-idle travel phase is when the real-time position is between the end of the idle travel phase and the engaged position.

[0042] Step S3: During the idle stroke stage, the electromagnetic attraction force is dynamically calculated based on the real-time feedback current value and air gap amount according to the electromagnetic attraction force physical model, and closed-loop pulse width modulation control is performed in combination with the spring force of the return device.

[0043] Step S4: If a separation command is received while the device is in the bonding state, the device will jump to the bonding state to perform separation control; if a bonding command is received while the device is in the bonding state, the device will jump to the bonding state to perform bonding control.

[0044] Specifically, in step S1: the controller divides the control state of the electromagnetic clutch into four states. The disengaged state is when the electromagnetic clutch is fully disengaged, at which point the clutch coil current is zero, and the return device keeps the actuator in the disengaged position. The engaged state is when the electromagnetic clutch is fully engaged, at which point sufficient current is maintained in the clutch coil, and the electromagnetic attraction force overcomes the return device's spring force, keeping the actuator in the engaged position. The transitional state between disengagement and engagement is the transitional state between the electromagnetic clutch and engagement, at which point the controller is executing disengagement control, the coil current gradually decreases to zero, and the actuator moves in the disengagement direction under the action of the return device's spring force. The transitional state between engagement and engagement is the transitional state between the electromagnetic clutch and engagement, at which point the controller is executing engagement control, the coil current gradually increases, and the actuator moves in the engagement direction under the action of the electromagnetic attraction force.

[0045] In this embodiment, the relative values ​​of the combined position and the disengagement position are obtained through measurements of the clutch's physical structure. The controller acquires the actual position of the clutch in real time via a position sensor. The end point of the free travel is the position from which the clutch begins to move from the disengagement position to the point where the actuator begins to contact the friction disc; this position can be predetermined through bench calibration. Those skilled in the art should understand that the specific value of the end point of the free travel varies depending on the clutch structure and can be obtained through actual measurement or simulation calculation; this invention does not impose any limitations on this.

[0046] Specifically, in step S2: when the hybrid vehicle controller determines that engine intervention is required, it sends an engagement command to the electromagnetic clutch control unit. After receiving the engagement command, the controller changes the requested state from disengaged to engaged, and the actual state from disengaged to engaged.

[0047] During engagement, the controller monitors the actual clutch position in real time, as fed back by the position sensor. and the end point of the empty journey Compare. If If the current process is in an empty travel phase; The system determines that the current position is in a non-empty travel phase. An empty travel phase occurs when the real-time position is in a separated position. End of empty journey During the intermediate phases, the non-empty travel phase occurs when the real-time position is at the end of the empty travel phase. and the position of union The control strategies for the two phases are compared in the table below:

[0048] Different pulse width modulation control strategies are adopted for different stages: in the idle travel stage, smoothness is the main control objective, and fine force balance control based on physical model is adopted; in the non-idle travel stage, response speed is the priority control objective, and fast calibration strategy is adopted.

[0049] During the assembly process, the controller monitors the input shaft speed and output shaft speed in real time and calculates the speed difference. .when When the speed difference is less than a preset threshold, it is determined that the speeds of the driving and driven discs are synchronized, engagement is complete, and the engagement state is switched to the engaged state. Those skilled in the art should understand that the speed difference threshold can be adjusted according to the specific clutch structural parameters and vehicle smoothness requirements; this invention does not impose any limitations on this.

[0050] Specifically, in step S3: during the idle travel phase, the controller performs real-time pulse width modulation calculation and closed-loop control based on the Maxwell electromagnetic attraction force physical model.

[0051] The controller obtains the current air gap amount, which is the difference between the current position and the real-time position, and obtains the real-time feedback coil current value. Based on the clutch structure parameters, it determines the effective magnetic area and the number of coil turns.

[0052] Calculate the current electromagnetic attraction force according to Maxwell's formula for electromagnetic attraction. : ; in, The permeability of free space, The number of coil turns. The effective magnetic area (m²) The coil current is (A). Let be the air gap (m). The physical meaning of this formula is: the electromagnetic attraction force is directly proportional to the square of the number of coil turns, the square of the current, and the effective magnetic area, and inversely proportional to the square of the air gap.

[0053] The controller calculates the spring force of the return device based on the spring characteristic curve of the return device. : ; in, This is the spring stiffness coefficient. This is the shape variable for the return device.

[0054] The net force is calculated as the electromagnetic attraction force minus the return force of the return mechanism. Based on Newton's second law, the controller calculates the current acceleration and predicts the position change in the next control cycle, adjusting the pulse width modulation value accordingly to achieve smooth acceleration.

[0055] Those skilled in the art should understand that the parameters in the above physical model, such as vacuum permeability, number of coil turns, effective magnetic area, spring stiffness coefficient, and armature mass, are inherent parameters of the clutch itself and can be obtained through design parameters or bench calibration. The controller executes the above calculation cycle at a preset period to achieve real-time closed-loop control based on the physical model.

[0056] During the non-no-load phase, the controller switches to a rapid engagement strategy, directly outputting a preset pulse width modulation value based on the parameters calibrated on the test bench to achieve a fast response. The switching threshold between the no-load and non-no-load phases is determined in real time based on the actual clutch position.

[0057] Specifically, such as Figure 3 As shown, in step S4: the controller supports a state machine interrupt jump mechanism.

[0058] During the engagement process, the actual state is engagement. If the controller detects a separation command from the vehicle controller, the controller immediately jumps to the separation control process, executes torque reduction, pulse width modulation output reset to zero, and return to separation, interrupting the ongoing engagement action.

[0059] During the separation process, the actual state is separation. If the controller detects a connection command from the vehicle controller, the controller immediately jumps to the connection control process, executes pulse width modulation calculation, excitation, and connection action, and interrupts the ongoing separation action.

[0060] In this embodiment, the specific method for switching to the separation state to perform separation control is as follows: The controller first sends a torque reduction command to the engine control unit to reduce the power output at the input shaft end; when the total input torque is less than a preset threshold, the controller sets the pulse width modulation output to zero, so that the clutch coil current drops to zero and the electromagnetic attraction force disappears; under the action of the return device's elastic force, the clutch actuator moves in the separation direction; when the actual position of the clutch reaches the separation position, the actual state becomes separation, and the clutch separation is completed.

[0061] Those skilled in the art will understand that the response time of the interrupt jump depends on the program cycle of the control unit and can meet the requirements of real-time response. The torque reduction threshold can be adjusted according to the powertrain characteristics and safety requirements of a specific vehicle, and this invention does not limit it.

[0062] Furthermore, in one embodiment, the method further includes a step of determining the minimum pulse width modulation threshold required to maintain engagement. After the clutch engages, the actual state becomes engaged, in which the electromagnetic clutch coil needs to maintain a constant current to retain the engagement state. The controller determines the minimum pulse width modulation value required to maintain engagement through boundary measurement.

[0063] The specific method for boundary measurement is as follows: The clutch is placed in the engaged state on a test bench, and the coil is driven with an initial pulse width modulation (PWM) value. The PWM value is gradually decreased in preset steps, maintaining each step for a preset time. The clutch position sensor signal is monitored in real time. When the position sensor detects that the actual clutch position deviates from the engaged position by more than a preset threshold, the current PWM value is recorded. This process is repeated multiple times, and the average value is taken as the minimum PWM threshold. In actual control, the output PWM value is increased by a preset margin based on this threshold to ensure the reliability of engagement maintenance.

[0064] This boundary measurement can be performed automatically when the vehicle rolls off the production line, or triggered by a diagnostic tool during maintenance, without the need for additional equipment.

[0065] Furthermore, in one embodiment, a step of monitoring the speed difference throughout the engagement process is also included. During engagement, the controller monitors the input shaft speed and output shaft speed in real time using a speed sensor and calculates the speed difference. When the speed difference is less than a preset threshold, it is determined that the speeds of the driving and driven discs are synchronized, and the engagement process enters the final stage; the controller continues to maintain the current pulse width modulation value until the actual clutch position reaches the engagement position, and then switches the actual state to the engagement state.

[0066] Full-process speed difference monitoring ensures the smoothness and safety of the engagement process, avoiding the impact caused by forced engagement when the speed difference is too large.

[0067] like Figure 1 As shown, an electromagnetic clutch control device provided in this embodiment includes: an electromagnetic clutch assembly, a signal detection device, a control unit, and a power drive circuit.

[0068] The electromagnetic clutch assembly includes a clutch coil, a clutch actuator, and a return mechanism. When the clutch coil is energized, it generates an electromagnetic force that drives the clutch actuator to move in the engagement direction against the elastic force of the return mechanism. The return mechanism is used to drive the clutch actuator to move in the disengagement direction when the clutch coil is de-energized.

[0069] The signal detection device includes a current sensor for sampling the current of the clutch coil, a speed sensor for detecting the rotational speeds of the clutch front and rear ends, and a position sensor for detecting the real-time position of the clutch actuator.

[0070] The control unit is connected to the signal detection device, receives control commands and detection signals from the signal detection device, and is configured to perform the method described in any of the above-mentioned embodiments.

[0071] The power drive circuit is connected to the control unit and the clutch coil, and controls the power supply to the clutch coil according to the pulse width modulation signal output by the control unit.

[0072] This embodiment also provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, it implements the steps of the electromagnetic clutch control method described in any of the above embodiments.

[0073] In one embodiment, the computer-readable storage medium can be any medium capable of storing program code, such as a read-only memory (ROM), random access memory (RAM), magnetic disk, optical disk, USB flash drive, or portable hard drive, or it can be a non-volatile memory integrated within a control unit. Those skilled in the art should understand that the specific type of storage medium does not constitute a limitation of the present invention.

[0074] When executed by the processor, the computer program performs the following steps: dividing the control state of the electromagnetic clutch into a disengaged state, an engaged state, a disengaged state, and an engaged state; upon receiving an engagement command, controlling the electromagnetic clutch to switch from the disengaged state to the engaged state; in the engaged state, determining whether the electromagnetic clutch is currently in the idle stroke stage or the non-idle stroke stage based on its real-time position, and employing different pulse width modulation control strategies for different stages; in the idle stroke stage, dynamically calculating the electromagnetic attraction force based on the electromagnetic attraction force physical model and the real-time feedback current value and air gap amount, and performing closed-loop pulse width modulation control in conjunction with the return device's spring force; in the engaged state, if a disengaged command is received, switching to the disengaged state to execute disengaged control; in the disengaged state, if an engagement command is received, switching to the engaged state to execute engaged control.

[0075] In one embodiment, the computer program further includes instructions for implementing the following steps: during the coupling process, real-time monitoring of the input shaft speed and the output shaft speed, calculation of the speed difference, and determining that coupling is complete when the speed difference is less than a preset threshold. In another embodiment, the computer program further includes instructions for implementing a step of determining a minimum pulse width modulation threshold for maintaining coupling.

[0076] The computer-readable storage medium can exist independently or be integrated into the electromagnetic clutch control unit as part of the control unit's internal firmware. During vehicle production, the computer program can be pre-installed on the storage medium; during vehicle use, the program on the storage medium can also be updated and upgraded via over-the-air (OTA) download technology.

[0077] Those skilled in the art should understand that the aforementioned storage medium and the computer program stored therein belong to the same inventive concept as the aforementioned method embodiments, device embodiments and system embodiments, and have the same or corresponding technical features and technical effects, which will not be repeated here.

[0078] In one specific implementation, taking the electromagnetic clutch control system of a hybrid vehicle as an example, the system hardware configuration is as follows: The electromagnetic clutch connects the engine and the drive motor, and includes a coil, armature, and return spring, with the spring stiffness coefficient calibrated on a test bench. The signal detection device includes a current sensor with a range of 0–20A and an accuracy of ±1%, a speed sensor with an accuracy of ±1 r / min, and a position sensor with a resolution of 0.01 mm. The control unit is the hybrid power system vehicle controller, with a built-in pulse width modulation generation module that executes one control cycle at a preset period. The power drive circuit is an H-bridge circuit composed of high-side and low-side switches.

[0079] Scenario 1: Combining Control During vehicle operation, the hybrid vehicle controller determines that the engine needs to intervene for drive and sends an engagement command to the electromagnetic clutch control unit.

[0080] Step 1, State transition: The request state changes from separated to combined, and the actual state changes from separated to combined.

[0081] Step 2, Pulse Width Modulation Calculation during Idle Stroke: The controller reads the current position and determines that it is in the idle stroke stage. The controller obtains the current deformation and calculates the return device's spring force. Based on Maxwell's electromagnetic attraction formula, combined with the real-time feedback current value and air gap amount, the current electromagnetic attraction force is calculated. The resultant force is calculated, and the pulse width modulation value is adjusted in a closed loop according to Newton's second law to achieve smooth acceleration.

[0082] Step 3, Pulse Width Modulation Calculation in the Non-Empty Stroke Phase: When the actual position exceeds the end point of the empty stroke, the non-empty stroke phase begins. The controller switches to a fast-combining strategy and outputs pulse width modulation values ​​based on the parameters calibrated on the test bench to achieve fast combination.

[0083] Step 4, Speed ​​Difference Monitoring: The controller monitors the input shaft speed and output shaft speed throughout the process and calculates the speed difference. When the speed difference is less than a preset threshold, the engagement is determined to be complete, and the engagement in progress state is switched to the engaged state.

[0084] Step 5, Engagement Maintenance: The actual state of the clutch becomes engaged. The controller determines the minimum pulse width modulation value to maintain engagement through boundary measurements and outputs a pulse width modulation value with a preset margin based on this threshold.

[0085] Scenario 2: Separate Control When a vehicle switches from hybrid drive mode to pure electric drive mode, the engine needs to be disengaged.

[0086] Step 1, reduce torque: The controller sends a torque reduction command to the engine control unit to reduce the power output at the input shaft end.

[0087] Step 2, Torque threshold judgment: When the total input torque is less than the preset threshold, the separation control is entered.

[0088] Step 3, State transition: The request state changes from combined to separated, and the actual state changes from combined to separated.

[0089] Step 4, Pulse Width Modulation Output: The controller sets the pulse width modulation output to zero, the clutch coil current drops to zero, and the electromagnetic attraction force disappears.

[0090] Step 5, return to separation: Under the elastic force of the return device, the clutch actuator moves in the separation direction.

[0091] Step 6, Disengagement complete: When the actual position of the clutch reaches the disengagement position, the actual state becomes disengaged, and the clutch disengagement is completed.

[0092] Scenario 3: Interruption Jump During engagement, a disengagement command is received: The clutch is in the process of engagement when the vehicle controller sends a disengagement command due to a change in operating conditions. The control unit immediately switches to the disengagement control flow, executing torque reduction, pulse width modulation output reset to zero, and return to disengagement, interrupting the ongoing engagement action.

[0093] During the disengagement process, an engagement command is received: The clutch is disengaging when the vehicle controller sends an engagement command due to a change in power demand. The control unit immediately switches to the engagement control flow, executes pulse width modulation calculation, excitation, and engagement actions, interrupting the ongoing disengagement process.

[0094] In some implementations, the position detection method is not limited to direct measurement by a position sensor, but can be replaced by indirect estimation of the clutch position through a current-position relationship model, or by calculating the clutch position through the integral of the speed difference; the pulse width modulation calculation method is not limited to precise calculation based on Maxwell's electromagnetic attraction force formula, but can be replaced by a pulse width modulation decision method based on fuzzy logic, or an adaptive pulse width modulation control method based on neural network learning; the power drive circuit is not limited to an H-bridge circuit, but can be replaced by a single-tube drive circuit or an integrated drive chip solution; the stage division is not limited to two stages, the idle stroke stage and the non-idle stroke stage, but can be further subdivided into more stages according to actual control requirements; the return device is not limited to a helical spring, but can be replaced by a disc spring, a pneumatic return device, or other elastic return mechanism.

[0095] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A control method for an electromagnetic clutch, characterized in that, Applied to hybrid vehicles, and executed by a controller, it includes: The control states of the electromagnetic clutch are divided into disengagement state, engagement state, disengagement state, and engagement state. When a engagement command is received, the electromagnetic clutch is controlled to switch from the disengaged state to the engaged state. In the engaged state, the real-time position of the electromagnetic clutch is used to determine whether it is in the no-travel stage or the non-no-travel stage. Different pulse width modulation control strategies are used for different stages. During the idle travel phase, the electromagnetic attraction force is dynamically calculated based on the real-time feedback current value and air gap amount according to the electromagnetic attraction force physical model, and closed-loop pulse width modulation control is performed in combination with the spring force of the return device. If a separation command is received while the device is in the combined state, the system will switch to the separation state to perform separation control; if a combination command is received while the device is in the separation state, the system will switch to the combination state to perform combination control.

2. The control method for an electromagnetic clutch according to claim 1, characterized in that, The disengaged state is when the electromagnetic clutch is in a fully disengaged position; the engaged state is when the electromagnetic clutch is in a fully engaged position; the disengaged state is the transitional state of the electromagnetic clutch moving from the engaged state to the disengaged state; the engaged state is the transitional state of the electromagnetic clutch moving from the disengaged state to the engaged state; the idle travel phase is the phase where the real-time position is between the disengaged position and the end of the idle travel phase; the non-idle travel phase is the phase where the real-time position is between the end of the idle travel phase and the engaged position.

3. The control method for an electromagnetic clutch according to claim 1, characterized in that, The physical model of the electromagnetic attraction force is the Maxwell electromagnetic attraction force model. The electromagnetic attraction force is directly proportional to the square of the number of coil turns, the square of the current, and the effective magnetic area, and inversely proportional to the square of the air gap. The pulse width modulation control dynamically calculates the target electromagnetic attraction force based on the real-time feedback current value and air gap, and performs closed-loop adjustment based on the resultant force of the target electromagnetic attraction force and the spring force of the return device.

4. The control method for an electromagnetic clutch according to claim 1, characterized in that, The pulse width modulation value during the idle travel phase is determined by a two-dimensional linear interpolation method, which calculates the interpolation based on the current position and target time in a pre-calibrated position-time-pulse width modulation value calibration table.

5. The control method for an electromagnetic clutch according to claim 1, characterized in that, The process of switching to the separation state to perform separation control includes: reducing the torque of the power source; when the input torque is less than a preset threshold, setting the pulse width modulation output to zero, reducing the coil current to zero, and achieving separation through the spring force of the return device.

6. The control method for an electromagnetic clutch according to claim 1, characterized in that, It also includes a step of determining the minimum pulse width modulation threshold for maintaining engagement: driving the coil in a manner that gradually decreases the pulse width modulation value, monitoring the clutch position signal, recording the current pulse width modulation value when the clutch position signal indicates that the clutch begins to deviate from the engagement position, and determining the minimum pulse width modulation threshold for maintaining engagement based on the current pulse width modulation value.

7. The control method for an electromagnetic clutch according to claim 1, characterized in that, Also includes: During the coupling process, the input shaft speed and output shaft speed are monitored in real time, and the speed difference is calculated. When the speed difference is less than a preset threshold, the coupling is determined to be complete, and the coupling state is switched to the coupling state.

8. An electromagnetic clutch control device, characterized in that, include: An electromagnetic clutch assembly includes a clutch coil, a clutch actuator, and a return device. When the clutch coil is energized, it generates an electromagnetic force to drive the clutch actuator to move in the engagement direction against the elastic force of the return device. When the clutch coil is de-energized, the return device drives the clutch actuator to move in the disengagement direction. The signal detection device includes a current sensor for sampling the current of the clutch coil, a speed sensor for detecting the rotational speed of the clutch front and rear ends, and a position sensor for detecting the real-time position of the clutch actuator. A control unit, connected to the signal detection device, receives control commands and detection signals from the signal detection device, and the control unit is configured to perform the method according to any one of claims 1 to 7; A power drive circuit is connected to the control unit and the clutch coil, and controls the power supply to the clutch coil according to the pulse width modulation signal output by the control unit.

9. An electromagnetic clutch control system, characterized in that, include: An electromagnetic clutch assembly, comprising a clutch coil, a clutch actuator, and a return mechanism; The signal detection device includes a current sensor for sampling the coil current and a position sensor for detecting the real-time position of the clutch; A control unit that receives control commands and detection signals from the signal detection device, the control unit being configured to perform the method according to any one of claims 1 to 7; The power drive circuit controls the power supply to the clutch coil according to the pulse width modulation signal output by the control unit.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the method according to any one of claims 1 to 7.

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