Magnetorheological damper, coil control circuit and coil control method

Abstract

The invention provides a magneto-rheological damper, a coil control circuit and a coil control method.The circuit comprises a load current collecting module, a voltage control module and a control module, the load current collecting module generates feedback voltage according to current flowing through a magnet exciting coil, the feedback voltage is reduced when the current is increased, and the voltage control module controls the current flowing through the magnet exciting coil. The control module is used for generating a first pulse signal according to the feedback voltage, the duty ratio of the first pulse signal is reduced along with the reduction of the feedback voltage, and the control module is used for adjusting the duty ratio of the driving voltage of the excitation coil when the duty ratio of the first pulse signal is reduced, so that the current flowing through the excitation coil is kept stable; therefore, the technical problem that the control precision of the magnetorheological damper is not high enough is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetorheological dampers, and in particular to a magnetorheological damper, a coil control circuit and a coil control method. Background Art

[0002] As a high-performance, adjustable vibration reduction device, magnetorheological dampers play a vital role in the automotive manufacturing field. Its working principle is based on the magnetorheological effect, that is, when the magnetorheological fluid is in a changing magnetic field, the magnetic particles inside it will quickly rearrange, thereby changing the overall flow characteristics of the fluid. By precisely controlling the current of the coil inside the damper, the strength of the magnetic induction intensity can be effectively adjusted, and then the viscosity of the magnetorheological fluid can be dynamically adjusted to convert it between Newtonian fluid and semi-solid. This conversion process causes a significant pressure difference between the upper and lower chambers of the damper, thereby generating the required damping force, and the process is completely reversible, which makes precise control possible.

[0003] In the pursuit of higher damping performance to meet the needs of specific application scenarios, a common strategy is to increase the number of excitation coils inside the damper. By increasing the number of coils, the length of the effective damping gap can be extended accordingly, thereby significantly improving the adjustment range of the damping force. This method has achieved remarkable results in improving the overall effectiveness of the damper. However, with the increase in the number of coils, the load current tends to become unstable under long-term continuous operation due to the accumulation of heat generated by the current passing through the coils and the influence of changes in the external working environment temperature. This instability not only affects the precise control of the damping force, but may also lead to a decrease in the overall performance of the system, especially in application scenarios with extremely high control accuracy requirements. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the related art, the present invention provides a magnetorheological damper, a coil control circuit and a coil control method to solve the technical problem that the control accuracy of the magnetorheological damper is not high enough.

[0005] The present invention provides a coil control circuit for a magnetorheological damper, comprising a load current acquisition module, which generates a feedback voltage according to a current flowing through an excitation coil, wherein the feedback voltage decreases when the current increases; a voltage control module, which generates a first pulse signal according to the feedback voltage, and the duty cycle of the first pulse signal decreases as the feedback voltage decreases; and a control module, which adjusts the duty cycle of the driving voltage of the excitation coil when the duty cycle of the first pulse signal decreases, so that the current flowing through the excitation coil remains stable.

[0006] In one embodiment of the present invention, the control module collects the coil temperature of the excitation coil and determines the compensation voltage based on the coil temperature; the control module inputs the compensation voltage into the load current acquisition module, so that the load current acquisition module performs voltage amplification based on the compensation voltage to obtain the feedback voltage.

[0007] In one embodiment of the present invention, the load current acquisition module includes: a load amplification unit, which samples the current flowing through the excitation coil and amplifies it to obtain a first voltage; an error comparison amplification unit, which corrects the first voltage according to a compensation voltage to obtain a second voltage; and an integral operation amplification voltage, which amplifies the second voltage to obtain a feedback voltage.

[0008] In one embodiment of the present invention, the load amplification unit includes a sampling resistor, a third resistor, a fourth resistor, a fifth resistor and a first amplifier; one end of the sampling resistor is connected to the output end of the excitation coil, and the other end of the sampling resistor is grounded; one end of the fourth resistor is connected to one end of the sampling resistor, and the other end of the fourth resistor is connected to the first input end of the first amplifier; one end of the fifth resistor is connected to the other end of the sampling resistor, and the other end of the fifth resistor is connected to the second input end of the first amplifier; one end of the third resistor is connected to the other end of the fourth resistor, and the other end of the third resistor is connected to the output end of the first amplifier.

[0009] In one embodiment of the present invention, the error comparison and amplification unit includes a sixth resistor, a seventh resistor, an eighth resistor, a tenth resistor and a second amplifier; one end of the sixth resistor is connected to the output end of the load amplification unit, and the other end of the sixth resistor is connected to the first input end of the second amplifier; one end of the seventh resistor is connected to the second output end of the control unit, and the other end of the seventh resistor is connected to the first input end of the second amplifier; one end of the eighth resistor is connected to the first input end of the second amplifier, and the other end of the eighth resistor is connected to the output end of the second amplifier; one end of the tenth resistor is connected to the second input end of the second amplifier, and the other end of the tenth resistor is grounded.

[0010] In one embodiment of the present invention, the integral operational amplifier unit includes a ninth resistor, an eleventh resistor, a twelfth sliding rheostat, a first capacitor and a third amplifier; one end of the ninth resistor is connected to the output end of the error comparison amplifier unit, and the other end of the ninth resistor is connected to the first input end of the third amplifier; one end of the eleventh resistor is connected to the second input end of the third amplifier, and the other end of the eleventh resistor is grounded; one end of the twelfth sliding rheostat is connected to the first input end of the third amplifier, and the sliding end of the twelfth sliding rheostat is connected to one end of the first capacitor; the other end of the twelfth sliding rheostat is connected to one end of the first capacitor; the other end of the first capacitor is connected to the output end of the third amplifier.

[0011] In one embodiment of the present invention, the voltage control module includes a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, a fourth amplifier and a calibration unit; one end of the fifteenth resistor is connected to the output end of the voltage control module, and the other end of the fifteenth resistor is connected to the second input end of the fourth amplifier; one end of the fourteenth resistor is grounded, and the other end of the fourteenth resistor is connected to the first input end of the fourth amplifier; one end of the thirteenth resistor is connected to the first input end of the fourth amplifier, and the other end of the thirteenth resistor is connected to the output end of the fourth amplifier; one end of the sixteenth resistor is connected to the power supply, and the other end of the sixteenth resistor is connected to the second input end of the fourth amplifier; one end of the seventeenth resistor is grounded, and the other end of the seventeenth resistor is connected to the second input end of the fourth amplifier; one end of the calibration unit is connected to the output end of the fourth amplifier, and the other end of the calibration unit is grounded.

[0012] An embodiment of the present invention also provides a coil control method for a magnetorheological damper, the method comprising generating a feedback voltage based on a current flowing through an excitation coil, wherein the feedback voltage decreases when the current increases; generating a first pulse signal based on the feedback voltage, the duty cycle of the first pulse signal decreases as the feedback voltage decreases; if the duty cycle of the first pulse signal decreases, adjusting the duty cycle of the driving voltage of the excitation coil so that the current flowing through the excitation coil remains stable.

[0013] An embodiment of the present invention further provides a magnetorheological damper, wherein the magnetorheological damper comprises a coil control circuit of the magnetorheological damper as described in any one of the above embodiments.

[0014] In one embodiment of the present invention, the damping channel of the magnetorheological damper includes a bent structure.

[0015] Beneficial effects of the invention: The embodiment of the invention provides a magnetorheological damper, a coil control circuit and a coil control method, the circuit comprising: a load current acquisition module, a voltage control module and a control module, the load current acquisition module generates a feedback voltage according to the current flowing through the excitation coil, wherein the feedback voltage decreases when the current increases, a voltage control module generates a first pulse signal according to the feedback voltage, and the duty cycle of the first pulse signal decreases as the feedback voltage decreases, and a control module adjusts the duty cycle of the driving voltage of the excitation coil when the duty cycle of the first pulse signal decreases, and when the temperature rises due to the long-term operation of the magnetorheological fluid, the current of the excitation coil is kept stable through the feedback adjustment of the current. When the coil temperature rises, the current passing through the excitation coil increases, the feedback voltage decreases, and the duty cycle of the first pulse signal decreases accordingly, thereby reducing the duty cycle of the driving voltage of the excitation coil to keep the current of the excitation coil stable, reducing the influence of temperature changes on the accuracy of the magnetorheological damper, and thus improving the control accuracy of the magnetorheological damper.

[0016] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a block diagram of a coil control circuit of a magnetorheological damper shown in an exemplary embodiment of the present invention;

[0018] Figure 2 is a schematic diagram of a coil control circuit of a magnetorheological damper shown in an exemplary embodiment of the present invention;

[0019] Figure 3 is a flow chart of a coil control method of a magnetorheological damper shown in an exemplary embodiment of the present invention;

[0020] Figure 4 is a flow chart of current recovery compensation of an excitation coil shown in an exemplary embodiment of the present invention;

[0021] Figure 5 is a schematic diagram of a magnetorheological damper shown in an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0022] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0023] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0024] It should be noted that, in the present invention, "first", "second", etc. are only used to distinguish similar objects, and are not used to limit the order or precedence of similar objects. The variations of "including", "having", etc. described above indicate that the scope of the subject of the word is not exclusive except for the examples shown by the word.

[0025] It is understood that the various numbers, step numbers and other labels recorded in the present invention are distinguished for the convenience of description and are not used to limit the scope of the present invention. The size of the labels in the present invention does not mean the order of execution. The execution order of each process should be determined by its function and internal logic.

[0026] In the following description, numerous details are discussed to provide a more thorough explanation of the embodiments of the present invention. However, it is obvious to those skilled in the art that the embodiments of the present invention can be implemented without these specific details. In other embodiments, well-known structures and devices are shown in the form of block diagrams rather than in detail to avoid making the embodiments of the present invention difficult to understand.

[0027] The embodiments of the present invention respectively provide a coil control circuit of a magnetorheological damper, a coil control method of a magnetorheological damper, and a magnetorheological damper. These embodiments will be described in detail below.

[0028] See also Figure 1 , Figure 1 It is a block diagram of a coil control circuit of a magnetorheological damper shown in an exemplary embodiment of the present invention. In one embodiment of the present invention, the coil control circuit of the magnetorheological damper includes a load current acquisition module 101, a voltage control module 102 and a control module 103; the load current acquisition module 101 generates a feedback voltage according to the current flowing through the excitation coil, wherein the feedback voltage decreases when the current increases; the voltage control module 102 generates a first pulse signal according to the feedback voltage, and the duty cycle of the first pulse signal decreases as the feedback voltage decreases; the control module 103 adjusts the duty cycle of the driving voltage of the excitation coil when the duty cycle of the first pulse signal decreases, so that the current flowing through the excitation coil remains stable.

[0029] Exemplarily, the load current acquisition module 101 samples the current flowing through the excitation coil based on a sampling resistor to obtain a sampling voltage, and amplifies the sampling voltage to obtain a feedback voltage, wherein the feedback voltage decreases as the current flowing through the excitation coil increases.

[0030] Exemplarily, the feedback voltage cannot be directly recognized by the control module, and the feedback voltage is filtered by the voltage control module 102 to obtain a first pulse signal that can be recognized by the control module 103, and the duty cycle of the first pulse signal decreases as the feedback voltage decreases.

[0031] For example, when the control module 103 identifies that the duty cycle of the first pulse signal decreases, it indicates that the current flowing through the excitation coil increases due to the increase in coil temperature, and the feedback voltage decreases. The control module 103 adjusts the duty cycle of the driving voltage of the excitation coil according to the first pulse signal, so that the current flowing through the excitation coil remains stable, improves the adjustment accuracy of the magnetorheological damper, and avoids inaccurate control caused by the increase in the excitation coil temperature.

[0032] In one embodiment of the present invention, the control module 103 collects the coil temperature of the excitation coil and determines the compensation voltage based on the coil temperature; the control module 103 inputs the compensation voltage into the load current acquisition module 101, so that the load current acquisition module 101 performs voltage amplification based on the compensation voltage to obtain the feedback voltage.

[0033] Exemplarily, a thermistor for detecting the coil temperature of the excitation coil is disposed in the excitation coil, and the control module 103 is connected to the thermistor to obtain the coil temperature of the excitation coil. The input end of the excitation coil is connected to the first output end of the control module 103, the output end of the excitation coil is connected to the load current acquisition module 101, one end of the thermistor is grounded, and the other end of the thermistor is connected to the control module 103; the input end of the load current acquisition module 101 is connected to the output end of the excitation coil, and the output end of the load current acquisition module 101 is connected to the voltage control module 102; the input end of the voltage control module 102 is connected to the load current acquisition module 101, and the output end of the voltage control module 102 is connected to the control module 103; the first input end of the control module 103 is connected to the voltage control module 102, the first output end of the control module 103 is connected to the excitation coil, and the second output end of the control module 103 is connected to the load current acquisition module 101. The control module 103 also determines a corresponding compensation voltage based on the coil temperature, and inputs the compensation voltage into the load current acquisition module 101, so that the load current acquisition module 101 performs voltage amplification based on the compensation voltage to obtain a feedback voltage.

[0034] In one embodiment of the present invention, the load current acquisition module 101 includes: a load amplification unit, which samples the current flowing through the excitation coil and amplifies it to obtain a first voltage; an error comparison amplification unit, which corrects the first voltage according to the compensation voltage to obtain a second voltage; and an integral operation amplification voltage, which amplifies the second voltage to obtain a feedback voltage.

[0035] Exemplarily, the input end of the load amplifier unit is connected to the output end of the excitation coil; the first input end of the error comparison amplifier unit is connected to the output end of the load amplifier unit, and the second input end of the error comparison amplifier unit is connected to the second output end of the control module 103; the input end of the integral operational amplifier unit is connected to the output end of the error comparison amplifier unit.

[0036] See also Figure 2 , Figure 2 It is a schematic diagram of a coil control circuit of a magnetorheological damper shown in an exemplary embodiment of the present invention.

[0037] Exemplarily, the load amplification unit includes a sampling resistor RS, a third resistor R3, a fourth resistor R4, a fifth resistor R5 and a first amplifier A1; one end of the sampling resistor RS is connected to the output end of the excitation coil L1, and the other end of the sampling resistor RS is grounded; one end of the fourth resistor R4 is connected to one end of the sampling resistor RS, and the other end of the fourth resistor R4 is connected to the first input end of the first amplifier A1; one end of the fifth resistor R5 is connected to the other end of the sampling resistor RS, and the other end of the fifth resistor R5 is connected to the second input end of the first amplifier A1; one end of the third resistor R3 is connected to the other end of the fourth resistor R4, and the other end of the third resistor R3 is connected to the output end of the first amplifier A1.

[0038] Exemplarily, the error comparison and amplification unit includes a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a tenth resistor R10 and a second amplifier A2; one end of the sixth resistor R6 is connected to the output end of the load amplification unit (i.e., the output end of the first amplifier A1), and the other end of the sixth resistor R6 is connected to the first input end of the second amplifier A2; one end of the seventh resistor R7 is connected to the second output end of the control unit 103, and the other end of the seventh resistor R7 is connected to the first input end of the second amplifier A2; one end of the eighth resistor R8 is connected to the first input end of the second amplifier A2, and the other end of the eighth resistor R8 is connected to the output end of the second amplifier A2; one end of the tenth resistor R10 is connected to the second input end of the second amplifier A2, and the other end of the tenth resistor R10 is grounded.

[0039] Exemplarily, the integral operational amplifier unit includes a ninth resistor R9, an eleventh resistor R11, a twelfth sliding rheostat R12, a first capacitor C1 and a third amplifier A3; one end of the ninth resistor R9 is connected to the output end of the error comparison amplifier unit (i.e., the output end of the second amplifier A2), and the other end of the ninth resistor R9 is connected to the first input end of the third amplifier A3; one end of the eleventh resistor R11 is connected to the second input end of the third amplifier A3, and the other end of the eleventh resistor R11 is grounded; one end of the twelfth sliding rheostat R12 is connected to the first input end of the third amplifier A3, and the sliding end of the twelfth sliding rheostat R12 is connected to one end of the first capacitor C1; the other end of the twelfth sliding rheostat R12 is connected to one end of the first capacitor C1; the other end of the first capacitor C1 is connected to the output end of the third amplifier A3.

[0040] Exemplarily, the voltage control module 102 includes a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor R17, a fourth amplifier A4 and a calibration unit; one end of the fifteenth resistor R15 is connected to the output end of the voltage control module 102 (i.e., the output end of the third amplifier A3), the other end of the fifteenth resistor R15 is connected to the second input end of the fourth amplifier A4, one end of the fourteenth resistor R14 is grounded, and the other end of the fourteenth resistor R14 is connected to the first input end of the fourth amplifier A4; one end of the thirteenth resistor R13 is connected to the first input end of the fourth amplifier A4, and the other end of the thirteenth resistor R13 is connected to the output end of the fourth amplifier A4; one end of the sixteenth resistor R16 is connected to the power supply, and the other end of the sixteenth resistor R16 is connected to the second input end of the fourth amplifier A4; one end of the seventeenth resistor R17 is grounded, and the other end of the seventeenth resistor R17 is connected to the second input end of the fourth amplifier A4; one end of the calibration unit is connected to the output end of the fourth amplifier A4, and the other end of the calibration unit is grounded.

[0041] Exemplarily, the calibration unit includes an eighteenth sliding rheostat R18, a nineteenth resistor R19 and a second capacitor C2; one end of the eighteenth sliding rheostat R18 is connected to the output end of the fourth amplifier A4, the other end of the eighteenth sliding rheostat R18 is connected to the nineteenth resistor R19, and the sliding end of the eighteenth sliding rheostat R18 is connected to the second capacitor C2; one end of the nineteenth resistor R19 is connected to the eighteenth resistor R18, and the other end of the nineteenth resistor R19 is grounded; one end of the second capacitor C2 is connected to the eighteenth sliding rheostat R18, and the other end of the second capacitor C2 is grounded.

[0042] Exemplarily, the coil control circuit of the magnetorheological damper further includes a first resistor R1, a first transistor Q1, a MOS switch Q2 and a voltage regulator D1, one end of the first resistor R1 is connected to the first output end of the control module 103, the other end of the first resistor R1 is connected to the first end (base) of the first transistor Q1, the second end (collector) of the first transistor Q1 is connected to the power supply, and the third end (emitter) of the first transistor Q1 is connected to the first end (gate) of the MOS switch Q2. One end of the second resistor R2 is connected to the third end (emitter) of the first transistor Q1, the other end of the second resistor R2 is grounded, one end of the voltage regulator D1 is connected to the first end (gate) of the MOS switch Q2, and the other end of the voltage regulator D1 is grounded. The second end (source) of the MOS switch Q2 is connected to the power supply, and the third end (drain) of the MOS switch Q2 is connected to the excitation coil L1.

[0043] Exemplarily, the coil control circuit of the magnetorheological damper also includes a twentieth resistor R20 and a thermistor RT, one end of the twentieth resistor R20 is connected to the power supply, the other end of the twentieth resistor R20 is connected to one end of the thermistor RT, the other end of the thermistor RT is grounded, and the control module 103 obtains the current coil temperature by collecting the voltage of the thermistor RT.

[0044] See also Figure 3 , Figure 3 FIG. 1 is a flow chart of a coil control method of a magnetorheological damper according to an exemplary embodiment of the present invention. Figure 3 As shown, in an exemplary embodiment, the coil control method of the magnetorheological damper includes at least steps S310 to S340, which are described in detail as follows:

[0045] In step S310 , a feedback voltage is generated according to the current flowing through the excitation coil, wherein the feedback voltage decreases when the current increases.

[0046] For example, the sampling resistor RS is connected in series with the excitation coil to sample the current of the excitation coil to obtain a sampling voltage, and the sampling voltage is input into the first amplifier A1 (load amplifier) ​​to obtain a first voltage V 1 , Where V s is the sampling voltage, R 3 is the resistance value of the third resistor R3, R 4 is the resistance value of the fourth resistor R4, and the sampling voltage increases as the current flowing through the excitation coil increases.

[0047] Exemplarily, the first voltage V 1 Input to the second amplifier A2 (error comparison amplifier) ​​to obtain the second voltage V 2 , since the resistance values ​​of the sixth resistor R6, the seventh resistor R7 and the eighth resistor R8 are the same, that is, R6 =R 7 =R 8 ,get Among them, V DA is the compensation voltage, R 3 is the resistance value of the third resistor R3, R 4 is the resistance value of the fourth resistor R4, V s The compensation voltage is the compensation voltage generated by the MCU (Microcontroller Unit) based on the coil temperature inside the excitation coil.

[0048] Exemplarily, the MCU (i.e., the control module 103) periodically obtains the coil temperature through the thermistor RT. When the MCU detects that the coil temperature at the current moment is higher than the coil temperature at the previous moment, a compensation voltage is obtained based on the difference between the coil temperature at the current moment and the coil temperature at the previous moment, and the compensation voltage is input into the load current acquisition module 101 to compensate the voltage. In this embodiment, the compensation voltage obtained by the coil temperature difference can be obtained by querying a mapping relationship table of a preset temperature difference and a compensation voltage.

[0049] For example, the second voltage V 2 Input to the third amplifier A3 (integrating operational amplifier) ​​to obtain the feedback voltage V 3 , Among them, R 9 is the resistance value of the ninth resistor R9, R 12 is the resistance value of the twelfth resistor R12, V 2 is the second voltage, C 1 is the capacitance of the first capacitor. When the current flowing through the excitation coil increases due to temperature rise, the sampling voltage V s Increase, V 2 Increase, V 3 Decreases, that is, the feedback voltage decreases when the current passing through the excitation coil increases.

[0050] Step S320 , generating a first pulse signal according to the feedback voltage, wherein the duty cycle of the first pulse signal decreases as the feedback voltage decreases.

[0051] For example, the feedback voltage V 3 The voltage control module 102 is input, and the first pulse signal is output through the fourth amplifier A4 of the voltage control module 102. The duty cycle of the first pulse signal follows the feedback voltage V 3 decreases with the decrease of .

[0052] Step S330: If the duty cycle of the first pulse signal decreases, the duty cycle of the driving voltage of the excitation coil is adjusted so that the current flowing through the excitation coil remains stable.

[0053] Exemplarily, after the MCU (control module 103) recognizes that the duty cycle of the first pulse signal is reduced, it adjusts the driving duty cycle of the first transistor Q1 to be reduced, thereby reducing the current of the excitation coil and maintaining the load current stable.

[0054] Exemplarily, the MCU adjusts the driving duty cycle of the excitation coil by sending a PWM (Pulse Width Modulation) signal, the first transistor Q1 is turned on and off according to the high and low levels of PWM, and drives the MOS switch Q2, thereby supplying power to the excitation coil, wherein the first resistor R1 provides negative feedback to ensure the stability of the amplification of the first transistor Q1. In the transistor amplifier circuit, the base resistor adjusts the collector current by monitoring the change of the base current, thereby maintaining the stability of the amplification.

[0055] See also Figure 4 , Figure 4 It is a flow chart of excitation coil current recovery compensation shown in an exemplary embodiment of the present invention. The excitation coil current recovery compensation process includes: when the MCU sends a PWM signal to drive the MOS switch Q2 to power the excitation coil, the MCU periodically collects the coil temperature of the excitation coil through the thermistor. When the MCU detects that the coil temperature rises, that is, the coil temperature difference between the coil temperature T2 at the second moment and the coil temperature T1 at the first moment is greater than 0, the MCU obtains a compensation voltage based on the coil temperature difference, and inputs the compensation voltage into the load current acquisition module 101. If the MCU detects that the first pulse signal changes, the PWM output is adjusted according to the duty cycle change of the first pulse signal, thereby adjusting the current of the excitation coil, so that the current flowing through the excitation coil remains stable.

[0056] Figure 5 is a schematic diagram of a magnetorheological damper according to an exemplary embodiment of the present invention. Figure 5 The magnetorheological damper structure shown in the figure at least includes a piston rod 501, a magnetorheological fluid inlet and outlet annular damping channel 502, a transverse damping channel 503, a magnetic conductive material 504, an annular damping channel 505, an excitation coil 506, a bend 507 and a piston 508. Among them, the coil control circuit of the magnetorheological damper is connected to the excitation coil 506, and the damping channel is composed of the magnetorheological fluid inlet and outlet annular damping channel 502, the transverse damping channel 503 and the annular damping channel 505.

[0057] according to Figure 5As shown, the piston rod 501 is connected to the piston 508, and the piston 508 can slide relatively. The magnetic conductive material 504 is arranged near the transverse damping channel 503 and the excitation coil 506. The magnetorheological fluid inlet and outlet annular damping channels 502, the transverse damping channel 503 and the annular damping channel 505 constitute the damping channel. A bend 507 of a bent structure is arranged in the damping channel, and the bend 507 is bent inward to form the transverse damping channel 503. The damping channel is provided with bent structures at multiple locations to form the transverse damping channel 503.

[0058] Among them, the magnetic conductive material 504 forms a magnetic field after the excitation coil 506 is energized. The increase of the magnetic conductive body can guide the magnetic lines of force to pass through the damping passage, thereby achieving the purpose of increasing the magnetic lines of force in the transverse damping channel 503 and the annular damping channel 505, thereby realizing the utilization rate of the magnetic field and effectively improving the adjustability of the magnetorheological damper.

[0059] like Figure 5 The total pressure drop of the magnetorheological damper shown is given by the following equation:

[0060] ΔP=2ΔP 1 +ΔP 2 +2ΔP 3 Formula (1)

[0061] In formula (1), ΔP 1 is the pressure drop of the annular damping channel at the inlet and outlet of the magnetorheological fluid, ΔP 2 represents the pressure drop in the lateral damping channel, ΔP 3 represents the pressure drop of the annular damping channel, and ΔP is the total pressure drop of the magnetorheological damper.

[0062] The pressure drop of the annular damping channel of the magnetorheological fluid inlet and outlet can be expressed as:

[0063]

[0064] In formula (2), η is the viscosity of the magnetic field magnetorheological fluid, q is the flow rate in the damping channel, b′ is the width of the annular damping channel at the inlet and outlet of the magnetorheological fluid, h is the width of the damping gap, l′ is the length of the annular damping channel at the inlet and outlet, c is the coefficient of the flow velocity profile, and τy is i is the dynamic yield stress of the magnetorheological fluid in the annular damping channel at the inlet and outlet.

[0065] Pressure drop in transverse damping channel ΔP 2 It can be expressed as:

[0066]

[0067] In formula (3), η is the viscosity of the magnetic field magnetorheological fluid, q is the flow rate in the damping channel, and R a is the inner diameter of the annular damping channel, R bis the outer diameter of the annular damping channel at the inlet and outlet of the magnetorheological fluid, Dynamic yield stress of magnetorheological fluid in the lateral damping channel.

[0068] Annular damping channel pressure drop ΔP 3 Can represent:

[0069]

[0070] In formula (4), η is the viscosity of the magnetic field magnetorheological fluid, q is the flow rate in the damping channel, b is the expansion width of the annular damping channel, l′ is the length of the annular damping channel at the inlet and outlet, and l is the length of the annular damping channel. is the dynamic yield stress of the magnetorheological fluid in the annular damping channel, c is the coefficient of the velocity profile, and h is the damping gap width.

[0071] Exemplarily, the viscosity of the magnetic field magnetorheological fluid, the expansion width of the annular damping channel, the length of the annular damping channel at the inlet and outlet, the length of the annular damping channel, the coefficient of the velocity profile, the width of the damping gap, the inner diameter of the annular damping channel, the outer diameter of the annular damping channel at the inlet and outlet of the magnetorheological fluid, the length of the annular damping channel at the inlet and outlet of the magnetorheological fluid, the expansion width of the annular damping channel at the inlet and outlet of the magnetorheological fluid, and the width of the damping gap can all be set according to the process parameters of the specific damper. Parameters such as the flow rate in the damping channel, the dynamic yield stress of the magnetorheological fluid in the annular damping channel at the inlet and outlet, the dynamic yield stress of the magnetorheological fluid in the lateral damping channel 503, and the dynamic yield stress of the magnetorheological fluid in the annular damping channel can be obtained based on the setting of sensors, or preset or calculated in advance.

[0072] When the magnetorheological fluid flows in the damping channel, when the pipeline suddenly contracts or expands and the flow direction suddenly changes, turbulence and other phenomena will occur, resulting in local pressure loss. Therefore, the local pressure in the liquid flow channel can be expressed as:

[0073]

[0074] In formula (5), ρ is the density of magnetorheological fluid, ε i is the i-th local loss coefficient, v i is the corresponding magnetorheological fluid flow rate. Wherein, the density and loss coefficient of the magnetorheological fluid are preset, and the magnetorheological fluid flow rate can be obtained based on a set sensor or preset.

[0075] For example, if the local pressure in the upper liquid flow channel is considered, the local pressure drop loss of the damper is ΔP″=2ΔP 1 +ΔP 2 +2ΔP 3 +ΔP′, where ΔP″ is the local pressure drop loss of the damper, ΔP 1 is the pressure drop of the annular damping channel at the inlet and outlet of the magnetorheological fluid, ΔP2 represents the pressure drop in the lateral damping channel, ΔP 3 represents the pressure drop of the annular damping channel. According to the effective area of ​​the piston 508, the overall output damping force can be calculated as: F = ΔP″ (A P -A d ), where A P is the area of ​​piston 508, A d is the area of ​​the piston rod 501. It can be seen from the calculation formula of the overall output damping force that without increasing the volume, as the magnetorheological fluid damping channel becomes longer, the effective magnetorheological damping length is increased and the magnetorheological fluid channel is suddenly turned to form shear force and resistance, which can greatly improve the output damping of the magnetorheological damper. At the same time, combined with the coil control circuit of the magnetorheological damper as described in the above embodiment, it can reduce the influence of the magnetorheological fluid temperature rising after a long period of operation, and the temperature is transferred to the excitation coil 506, causing the coil resistance to change, resulting in instability of the load current. By adjusting the current stability of the excitation coil 506, the magnetic field generated by the excitation coil 506 can be accurately controlled, thereby improving the accuracy of the damper.

[0076] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A coil control circuit for a magnetorheological damper, characterized in that: The coil control circuit of the magnetorheological damper comprises: A load current acquisition module, which generates a feedback voltage according to the current flowing through the excitation coil, wherein the feedback voltage decreases when the current increases; a voltage control module, which generates a first pulse signal according to the feedback voltage, wherein the duty cycle of the first pulse signal decreases as the feedback voltage decreases; A control module adjusts the duty cycle of the driving voltage of the excitation coil when the duty cycle of the first pulse signal decreases, so that the current flowing through the excitation coil remains stable.

2. The coil control circuit of the magnetorheological damper according to claim 1, characterized in that: The control module collects the coil temperature of the excitation coil and determines the compensation voltage based on the coil temperature; The control module inputs the compensation voltage into the load current acquisition module, so that the load current acquisition module performs voltage amplification based on the compensation voltage to obtain the feedback voltage.

3. The coil control circuit of the magnetorheological damper according to claim 1, characterized in that: The load current acquisition module comprises: A load amplifying unit, sampling and amplifying the current flowing through the excitation coil to obtain a first voltage; an error comparison and amplification unit, which corrects the first voltage according to a compensation voltage to obtain a second voltage; The voltage is amplified by integration operation, and the second voltage is amplified to obtain a feedback voltage.

4. The coil control circuit of the magnetorheological damper according to claim 3, characterized in that: The load amplification unit includes a sampling resistor, a third resistor, a fourth resistor, a fifth resistor and a first amplifier; One end of the sampling resistor is connected to the output end of the excitation coil, and the other end of the sampling resistor is grounded; One end of the fourth resistor is connected to one end of the sampling resistor, and the other end of the fourth resistor is connected to the first input end of the first amplifier; One end of the fifth resistor is connected to the other end of the sampling resistor, and the other end of the fifth resistor is connected to the second input end of the first amplifier; One end of the third resistor is connected to the other end of the fourth resistor, and the other end of the third resistor is connected to the output end of the first amplifier.

5. The coil control circuit of the magnetorheological damper according to claim 3, characterized in that: The error comparison and amplification unit includes a sixth resistor, a seventh resistor, an eighth resistor, a tenth resistor and a second amplifier; One end of the sixth resistor is connected to the output end of the load amplification unit, and the other end of the sixth resistor is connected to the first input end of the second amplifier; One end of the seventh resistor is connected to the second output end of the control unit, and the other end of the seventh resistor is connected to the first input end of the second amplifier; One end of the eighth resistor is connected to the first input end of the second amplifier, and the other end of the eighth resistor is connected to the output end of the second amplifier; One end of the tenth resistor is connected to the second input end of the second amplifier, and the other end of the tenth resistor is grounded.

6. The coil control circuit of the magnetorheological damper according to claim 3, characterized in that: The integral operational amplifier unit includes a ninth resistor, an eleventh resistor, a twelfth sliding variable resistor, a first capacitor and a third amplifier; One end of the ninth resistor is connected to the output end of the error comparison and amplification unit, and the other end of the ninth resistor is connected to the first input end of the third amplifier; One end of the eleventh resistor is connected to the second input end of the third amplifier, and the other end of the eleventh resistor is grounded; One end of the twelfth sliding rheostat is connected to the first input end of the third amplifier, and the sliding end of the twelfth sliding rheostat is connected to one end of the first capacitor; the other end of the twelfth sliding rheostat is connected to one end of the first capacitor; The other end of the first capacitor is connected to the output end of the third amplifier.

7. The coil control circuit of the magnetorheological damper according to claim 1, characterized in that: The voltage control module includes a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, a fourth amplifier and a calibration unit; One end of the fifteenth resistor is connected to the output end of the voltage control module, and the other end of the fifteenth resistor is connected to the second input end of the fourth amplifier; One end of the fourteenth resistor is grounded, and the other end of the fourteenth resistor is connected to the first input end of the fourth amplifier; One end of the thirteenth resistor is connected to the first input end of the fourth amplifier, and the other end of the thirteenth resistor is connected to the output end of the fourth amplifier; One end of the sixteenth resistor is connected to the power supply, and the other end of the sixteenth resistor is connected to the second input end of the fourth amplifier; One end of the seventeenth resistor is grounded, and the other end of the seventeenth resistor is connected to the second input end of the fourth amplifier; One end of the calibration unit is connected to the output end of the fourth amplifier, and the other end of the calibration unit is grounded.

8. A coil control method for a magnetorheological damper, characterized in that: The coil control method of the magnetorheological damper comprises: generating a feedback voltage according to a current flowing through the excitation coil, wherein the feedback voltage decreases when the current increases; generating a first pulse signal according to the feedback voltage, wherein the duty cycle of the first pulse signal decreases as the feedback voltage decreases; If the duty cycle of the first pulse signal decreases, the duty cycle of the driving voltage of the excitation coil is adjusted so that the current flowing through the excitation coil remains stable.

9. A magnetorheological damper, characterized in that: The magnetorheological damper comprises a coil control circuit of the magnetorheological damper as claimed in any one of claims 1 to 7.

10. The magnetorheological damper according to claim 9, characterized in that: The damping channel of the magnetorheological damper includes a bent structure.

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