EMB piston absolute position detection method and device

Abstract

The invention relates to an EMB piston absolute position detection method and device, and the method comprises the steps: 1, obtaining a first rotation angle and a second rotation angle, the first rotation angle being the rotation angle of a first transmission part, and the second rotation angle being the rotation angle of a second transmission part; the first transmission part is in transmission connection with the second transmission part, and the second transmission part is in transmission connection with the piston through a first transmission assembly; 2, obtaining a first rotation angle value according to the first rotation angle, and obtaining a second rotation angle value according to the second rotation angle; 3, obtaining a first increment angle signal and a second increment angle signal through increment calculation according to the first rotation angle value and the second rotation angle value, and obtaining an absolute angle value according to the first increment angle signal and the second increment angle signal; and 4, obtaining the absolute position of the piston according to the absolute angle value. According to the invention, the detection precision of the absolute position of the EMB piston is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic mechanical braking, and in particular relates to an EMB piston absolute position detection method and device. Background Art

[0002] Electro-Mechanical Brake (EMB) piston position detection technology is primarily used in the brake-by-wire systems of new energy vehicles and intelligent driving vehicles. As traditional hydraulic brakes are replaced by electronically controlled actuators, accurately acquiring piston displacement becomes a core requirement for fast-response, high-precision braking. This technology uses non-contact sensors to monitor piston movement in real time, resolving the cumulative error problem associated with traditional position detection. This ensures safety and control reliability in scenarios such as emergency braking and energy recovery. It is suitable for integrated chassis control and autonomous driving redundant systems, and is a key technology for the next generation of brake-by-wire chassis.

[0003] As the core of brake-by-wire technology, EMB's position detection accuracy directly impacts braking performance and driving safety. Currently, the industry primarily employs two technical approaches: relative position sensor solutions and absolute position sensor solutions, both of which present significant technical bottlenecks.

[0004] Traditionally, the widely used incremental encoder achieves position detection through pulse counting, a relative measurement mechanism with inherent flaws. Each time the system loses power, the mechanical position reference is lost, requiring a reset and calibration process to re-establish the initial position. This not only increases the brake preparation time by approximately 0.5 to 1.2 seconds but can also result in a cumulative error of ±0.15 mm / min during continuous operation. In urban driving conditions with frequent starts and stops, this accumulated error can lead to inaccurate brake pad clearance control. In extreme cases, this can cause a nonlinear relationship between brake pedal travel and braking force, significantly impacting the response speed and safety of the braking system.

[0005] While absolute position sensors can address the issue of lost reference points, their implementation faces multiple technical obstacles. For example, the core Hall element array of a magnetic encoder must remain strictly parallel to the piston's axis of motion, with installation tolerances within ±0.3mm. This poses significant challenges to the compact, integrated design of an EMB. Regarding temperature characteristics, when the braking system's operating temperature exceeds 150°C, the residual magnetism of the magnetic material attenuates by 6% to 8%, resulting in a ±2° phase shift in the position signal. Furthermore, high-frequency vibrations of 20 to 200 Hz generated by the vehicle during driving can induce mechanical resonance in the sensor, resulting in periodic measurement errors of 0.05 to 0.12 mm. This dynamic interference is difficult to completely eliminate using conventional filtering algorithms. Furthermore, the cost of a single absolute position sensor is 40% to 60% higher than that of incremental solutions, severely hindering its widespread adoption in commercial vehicles. Therefore, a method and device for detecting piston position in an EMB is needed. Summary of the Invention

[0006] In order to solve the above problems existing in the prior art, the present invention provides an EMB piston absolute position detection method and device. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0007] The present invention provides an EMB piston absolute position detection method, comprising:

[0008] Step 1: Obtain a first rotation angle and a second rotation angle, respectively, wherein the first rotation angle is the rotation angle of the first transmission member, and the second rotation angle is the rotation angle of the second transmission member; the first transmission member and the second transmission member are in transmission connection with each other, and the second transmission member and the piston are in transmission connection via the first transmission assembly;

[0009] Step 2: obtaining a first rotation angle value according to the first rotation angle, and obtaining a second rotation angle value according to the second rotation angle;

[0010] Step 3: Obtain a first incremental angle signal and a second incremental angle signal respectively through incremental calculation according to the first rotation angle value and the second rotation angle value, and obtain an absolute angle value according to the first incremental angle signal and the second incremental angle signal;

[0011] Step 4: Obtain the absolute position of the piston according to the absolute angle value.

[0012] In one embodiment of the present invention, a first magnet is connected to the first transmission member for obtaining a first rotation angle, and a first detection component is used to obtain the first rotation angle value based on the first rotation angle; a second magnet is connected to the second transmission member for obtaining a second rotation angle, and a second detection component is used to obtain the second rotation angle value based on the second rotation angle.

[0013] In one embodiment of the present invention, the incremental calculation includes: accumulating the angle increment of the first rotation angle value along with the time change to obtain a first incremental angle signal; accumulating the angle increment of the second rotation angle value along with the time change to obtain a second incremental angle signal.

[0014] In one embodiment of the present invention, the first rotation angle value includes a first rotation angle detection value and a first rotation angle redundancy value, and the first rotation angle redundancy value is used to perform redundancy check on the first rotation angle detection value; the second rotation angle value includes a second rotation angle detection value and a second rotation angle redundancy value, and a normalization calculation is performed based on the second rotation angle detection value and the second rotation angle redundancy value to obtain a first normalized rotation angle signal and a second normalized rotation angle signal, respectively; wherein, the first normalized rotation angle signal is used to perform redundancy check on the first rotation angle detection value, and the second normalized rotation angle signal is used to perform redundancy check on the first rotation angle redundancy value.

[0015] In one embodiment of the present invention, the normalization calculation includes:

[0016] According to the second rotation angle detection value and the transmission ratio between the first transmission member and the second transmission member, a remainder is taken to obtain a first normalized rotation angle signal, which is expressed as follows:

[0017] A31=MOD(A21*m,360);

[0018] A31 is the first normalized rotation angle signal; MOD is the modulo function; A21 is the second rotation angle detection value; m is the transmission ratio between the first transmission member and the second transmission member;

[0019] According to the second rotation angle redundancy value and the transmission ratio between the first transmission member and the second transmission member, a remainder is taken to obtain a second normalized rotation angle signal, which is expressed as follows:

[0020] A32=MOD(A22*m,360);

[0021] A32 is the second normalized rotation angle signal; A22 is the second rotation angle redundant value.

[0022] In one embodiment of the present invention, obtaining an absolute angle value according to the first incremental angle signal and the second incremental angle signal includes:

[0023] An absolute angle difference is obtained according to the difference between the first incremental angle signal and the second incremental angle signal. The absolute angle value is obtained according to the absolute angle difference, and the expression thereof is:

[0024] A121=A110-A210;

[0025] A1=A121*j;

[0026] Among them, A121 is the first absolute angle difference; A110 is the first incremental angle measurement signal; A210 is the second incremental angle measurement signal; A1 is the first absolute angle value; and j is the transmission coefficient.

[0027] In one embodiment of the present invention, obtaining the absolute position of the piston according to the absolute angle value includes:

[0028] Obtaining the absolute position of the piston according to the absolute angle value and a total transmission ratio between the first transmission member, the second transmission member, and the first transmission assembly; wherein the first transmission assembly includes a third transmission member and a fourth transmission member;

[0029] The absolute position of the piston is expressed as:

[0030] P = (A / 360 / i′)*s;

[0031] i′=m*n;

[0032] P is the absolute position of the piston; A is the absolute angle value; i′ is the total transmission ratio between the first transmission member, the second transmission member and the first transmission assembly; n is the transmission ratio between the second transmission member and the third transmission member; s is the transmission coefficient of the fourth transmission member.

[0033] The present invention also provides an EMB piston absolute position detection device, which is used for the above-mentioned EMB piston absolute position detection method. The device includes: a first transmission member, a first magnet, a first detection component, a second transmission member, a second magnet, a second detection component, a first transmission component and a piston, wherein the first transmission member, the second transmission member, the first transmission component and the piston are connected in sequence; the first magnet is used to obtain the rotation angle of the first transmission member to obtain the first rotation angle; the first detection component is used to obtain the first rotation angle value based on the first rotation angle; the second magnet is used to obtain the rotation angle of the second transmission member to obtain the second rotation angle; the second detection component is used to obtain the second rotation angle value based on the second rotation angle.

[0034] In one embodiment of the present invention, the first transmission member is coaxially connected to the rotor of the brake motor, and the first magnet is also used to obtain the rotation angle of the rotor of the brake motor to obtain the rotor rotation angle; the first detection component is also used to obtain the rotor rotation angle value based on the rotor rotation angle.

[0035] In one embodiment of the present invention, the EMB piston absolute position detection device further includes: a control processing component, wherein the control processing component is respectively connected to the brake motor, the first detection component and the second detection component, and is used to respectively obtain the rotor rotation angle value, the first rotation angle value and the second rotation angle value, and obtain a first incremental angle signal and a second incremental angle signal according to the first rotation angle value and the second rotation angle value; then obtain an absolute angle value according to the first incremental angle signal and the second incremental angle signal, and obtain the absolute position of the piston according to the absolute angle value; finally, control the brake motor according to the absolute position of the piston.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The EMB piston absolute position detection method disclosed herein achieves high-precision detection of the piston's absolute position by separately acquiring the rotation angles of the first and second transmission members, avoiding the accuracy loss caused by mechanical wear in traditional contact-based detection. This method utilizes a redundant verification mechanism for dual-angle signals to achieve high-precision detection without cumulative error over the entire stroke. This addresses the complex installation and weak anti-interference capabilities of existing absolute position sensors, improves the long-term reliability and adaptability of EMB piston absolute position detection, and meets the stringent requirements for millimeter-level displacement control in vehicle braking.

[0038] This invention significantly improves the reliability and safety of EMB piston absolute position detection through multi-level redundant verification. It employs dual-path rotation angle detection, with each path also configured as two-path. Redundancy verification and fault self-diagnosis are achieved through cross-validation of primary and backup signals. When a redundant verification anomaly occurs in one signal path, the other path is automatically switched to. This effectively resolves the control inaccuracy issues associated with sensor failure in traditional solutions. Furthermore, the non-contact detection method avoids mechanical wear and high-temperature interference, and combined with redundant verification, ensures long-term stable measurement accuracy, providing a technical foundation for the large-scale application of wire-controlled brake systems.

[0039] The EMB piston absolute position detection device, through the collaborative design of dual transmission components, magnets, and detection components, simplifies sensor layout and reduces installation precision requirements. By eliminating the need for complex calibration procedures, the risk of cumulative error is reduced. Furthermore, the device is compatible with existing brake motors, significantly lowering manufacturing costs and maintenance.

[0040] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following preferred embodiments are specifically cited and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a flow chart of an EMB piston absolute position detection method provided by an embodiment of the present invention;

[0042] Figure 2 is a signal waveform diagram of a first rotation angle value and a second rotation angle value provided by an embodiment of the present invention;

[0043] Figure 3 is a waveform diagram of a first incremental angle signal and a second incremental angle signal provided by an embodiment of the present invention;

[0044] Figure 4 1 is a structural diagram of an EMB piston absolute position detection device provided by an embodiment of the present invention;

[0045] Figure 5 3 is a signal diagram of the EMB piston absolute position detection device provided in an embodiment of the present invention.

[0046] Reference numerals: 1-first transmission member; 2-second transmission member; 3-first transmission assembly; 31-third transmission member; 32-fourth transmission member; 4-piston; 5-first detection assembly; 6-second detection assembly; 7-first magnet; 8-second magnet; 9-brake motor; 10-control processing assembly;

[0047] A01-first rotation angle; A11-first rotation angle detection value; A12-first rotation angle redundancy value; A1D-redundancy check result of the first rotation angle detection value and the first rotation angle redundancy value; A13D1-redundancy check result of the first rotation angle detection value and the first normalized rotation angle signal; A110-first incremental angle measurement signal; A120-first incremental angle redundancy signal; A121-first absolute angle difference; A1-first absolute angle value; P1-absolute position obtained according to the first absolute angle value; SP1-speed value obtained according to the first absolute angle value; A02-second rotation angle; A21-first Two rotation angle detection values; A22-second rotation angle redundant value; A31-first normalized rotation angle signal; A32-second normalized rotation angle signal; A2D-redundancy check result of the second rotation angle detection value and the second rotation angle redundant value; A13D2-redundancy check result of the second rotation angle detection value and the second normalized rotation angle signal; A210-second incremental angle measurement signal; A220-second incremental angle redundant signal; A122-second absolute angle difference; A2-second absolute angle value; P2-absolute position obtained according to the second absolute angle value; SP2-speed value obtained according to the second absolute angle value. DETAILED DESCRIPTION

[0048] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the following is a detailed description of an EMB piston absolute position detection method and device proposed in accordance with the present invention in conjunction with the accompanying drawings and specific implementation methods.

[0049] The aforementioned and other technical contents, features, and effects of the present invention are clearly presented in the following detailed description of the specific embodiments in conjunction with the accompanying drawings. Through the description of the specific embodiments, a deeper and more specific understanding of the technical means and effects adopted by the present invention to achieve the intended purpose can be obtained. However, the accompanying drawings are provided for reference and illustration purposes only and are not intended to limit the technical solutions of the present invention.

[0050] Example 1

[0051] The existing EMB system has problems such as insufficient piston displacement detection accuracy, difficulty in installing absolute position sensors, and the need for power-on self-learning of relative position sensors, which increases response time and poses safety risks, weak anti-interference ability, and poor long-term reliability. In view of this, the present invention provides an EMB piston absolute position detection method, such as Figure 1 As shown, Figure 1 This is a flow chart of an EMB piston absolute position detection method provided by an embodiment of the present invention.

[0052] In this embodiment, the EMB piston absolute position detection method includes:

[0053] Step 1: Obtain a first rotation angle and a second rotation angle respectively, wherein the first rotation angle is the rotation angle of the first transmission member, and the second rotation angle is the rotation angle of the second transmission member; the first transmission member and the second transmission member are in transmission connection, and the second transmission member and the piston are in transmission connection via the first transmission assembly;

[0054] Step 2: Obtain a first rotation angle value according to the first rotation angle, and obtain a second rotation angle value according to the second rotation angle.

[0055] In an optional embodiment, the first magnet is connected to the first transmission member for obtaining the first rotation angle, and the first detection component is used to obtain the first rotation angle value based on the first rotation angle; the second magnet is connected to the second transmission member for obtaining the second rotation angle, and the second detection component is used to obtain the second rotation angle value based on the second rotation angle.

[0056] Exemplarily, the first detection component and the second detection component both realize non-contact measurement based on the principle of magnetoresistance. The first magnet and the second magnet both have magnetic poles. When the first magnet and the second magnet rotate with the first transmission member and the second transmission member respectively, the first detection component and the second detection component detect the change of the magnetic poles and convert the angle of the magnetic pole change into a rotation angle value, that is, convert the physical rotation angle into a digital signal.

[0057] Step 3: According to the first rotation angle value and the second rotation angle value, a first incremental angle signal and a second incremental angle signal are obtained through incremental calculation respectively, and an absolute angle value is obtained according to the first incremental angle signal and the second incremental angle signal.

[0058] In an optional embodiment, the incremental calculation includes: accumulating the angle increment of the first rotation angle value along with the time change to obtain a first incremental angle signal; accumulating the angle increment of the second rotation angle value along with the time change to obtain a second incremental angle signal.

[0059] like Figure 2 and Figure 3 As shown, Figure 2 is a signal waveform diagram of a first rotation angle value and a second rotation angle value provided by an embodiment of the present invention; Figure 3 3 is a waveform diagram of the first incremental angle signal and the second incremental angle signal provided by an embodiment of the present invention.

[0060] It can be seen that before incremental calculation, the first and second rotation angle values both vary periodically between 0 and 360°. That is, without incremental calculation, their angle values only reflect relative position changes within a single rotation. However, after incremental calculation, by accumulating the angle changes, the first and second incremental angle signals exhibit a continuous increase, allowing the incremental angle signals to measure multiple rotations. The maximum number of measurable rotations is related to the transmission ratio between the first transmission member, the second transmission member, and the first transmission assembly.

[0061] In an optional embodiment, the first rotation angle value includes a first rotation angle detection value and a first rotation angle redundancy value, and the first rotation angle redundancy value is used to perform redundancy check on the first rotation angle detection value; the second rotation angle value includes a second rotation angle detection value and a second rotation angle redundancy value, and a normalization calculation is performed based on the second rotation angle detection value and the second rotation angle redundancy value to obtain a first normalized rotation angle signal and a second normalized rotation angle signal, respectively; wherein the first normalized rotation angle signal is used to perform redundancy check on the first rotation angle detection value, and the second normalized rotation angle signal is used to perform redundancy check on the first rotation angle redundancy value.

[0062] It is worth noting that there are two independent angle values for the first rotation angle value and the second rotation angle value, and the two angle values are redundant with each other. Redundancy verification is performed on the two redundant angle values to judge the validity and consistency of each signal, so that when a fault occurs, it can be discovered in time and the other signal that has not failed can be used to ensure the accuracy and precision of the detection.

[0063] Furthermore, the second rotation angle value can be normalized to the first rotation angle value through normalization calculation, that is, the rotational motion of the first transmission member and the second transmission member are linked, thereby further improving the detection accuracy. At the same time, after normalization, redundancy check can also be performed to achieve fault detection.

[0064] Specifically, the normalization calculation includes: taking the remainder according to the second rotation angle detection value and the transmission ratio between the first transmission member and the second transmission member to obtain a first normalized rotation angle signal, which is expressed as follows:

[0065] A31=MOD(A21*m,360);

[0066] A31 is the first normalized rotation angle signal; MOD is the modulo function; A21 is the second rotation angle detection value; m is the transmission ratio between the first transmission member and the second transmission member;

[0067] According to the second rotation angle redundancy value and the transmission ratio between the first transmission member and the second transmission member, the remainder is taken to obtain a second normalized rotation angle signal, which is expressed as follows:

[0068] A32=MOD(A22*m,360);

[0069] A32 is the second normalized rotation angle signal; A22 is the second rotation angle redundant value.

[0070] In an optional embodiment, obtaining the absolute angle value according to the first incremental angle signal and the second incremental angle signal includes:

[0071] The absolute angle difference is obtained according to the difference between the first incremental angle signal and the second incremental angle signal. The absolute angle value is obtained according to the absolute angle difference. The expression is:

[0072] A121=A110-A210;

[0073] A1=A121*j;

[0074] Among them, A121 is the first absolute angle difference; A110 is the first incremental angle measurement signal; A210 is the second incremental angle measurement signal; A1 is the first absolute angle value; and j is the transmission coefficient.

[0075] It can be understood that when no fault occurs, the values of the detection signal and the redundant signal should be the same. Therefore, here only one set of measurement signals is used as an example to obtain the absolute angle difference. The method and process for obtaining the absolute angle difference based on the remaining signals are similar, so they will not be repeated.

[0076] Step 4: Get the absolute position of the piston based on the absolute angle value.

[0077] In an optional embodiment, step 4 includes:

[0078] Obtaining an absolute position of the piston based on the absolute angle value and a total transmission ratio between the first transmission member, the second transmission member, and the first transmission assembly; wherein the first transmission assembly includes a third transmission member and a fourth transmission member;

[0079] The absolute position of the piston is expressed as:

[0080] P = (A / 360 / i′)*s;

[0081] i′=m*n;

[0082] P is the absolute position of the piston; A is the absolute angle value; i′ is the total transmission ratio between the first transmission member, the second transmission member and the first transmission assembly; n is the transmission ratio between the second transmission member and the third transmission member; s is the transmission coefficient of the fourth transmission member.

[0083] The EMB piston absolute position detection method disclosed herein achieves high-precision detection of the piston's absolute position by separately acquiring the rotation angles of the first and second transmission members, avoiding the accuracy loss caused by mechanical wear in traditional contact-based detection. This method utilizes a redundant verification mechanism for dual-angle signals to achieve high-precision detection without cumulative error over the entire stroke. This addresses the complex installation and weak anti-interference capabilities of existing absolute position sensors, improves the long-term reliability and adaptability of EMB piston absolute position detection, and meets the stringent requirements for millimeter-level displacement control in vehicle braking.

[0084] This invention significantly improves the reliability and safety of EMB piston absolute position detection through multi-level redundant verification. It employs dual-path rotation angle detection, with each path also configured as two-path. Redundancy verification and fault self-diagnosis are achieved through cross-validation of primary and backup signals. When a redundant verification anomaly occurs in one signal path, the other path is automatically switched to. This effectively resolves the control inaccuracy issues associated with sensor failure in traditional solutions. Furthermore, the non-contact detection method avoids mechanical wear and high-temperature interference, and combined with redundant verification, ensures long-term stable measurement accuracy, providing a technical foundation for the large-scale application of wire-controlled brake systems.

[0085] Example 2

[0086] The EMB system is mainly composed of a brake motor, a reduction mechanism and a piston, wherein the reduction mechanism can be a reduction gear set, a planetary gear, a ball screw, a roller screw or a trapezoidal nut and a combination thereof. In this embodiment, the combination of a reduction gear set and a ball screw is used as an example for illustration.

[0087] like Figure 3 As shown, Figure 33 is a signal diagram of the EMB piston absolute position detection device provided in an embodiment of the present invention.

[0088] This embodiment provides an EMB piston absolute position detection device, which is used for the EMB piston absolute position detection method of embodiment 1. The device includes: a first transmission member 1, a second transmission member 2, a first transmission assembly 3, a piston 4, a first detection assembly 5, a second detection assembly 6, a first magnet 7 and a second magnet 8, wherein the first transmission member 1, the second transmission member 2, the first transmission assembly 3 and the piston 4 are connected in transmission sequence; the first magnet 7 is used to obtain the rotation angle of the first transmission member 1 to obtain the first rotation angle; the first detection assembly 5 is used to obtain the first rotation angle value based on the first rotation angle; the second magnet 7 is used to obtain the rotation angle of the second transmission member 2 to obtain the second rotation angle; the second detection assembly 6 is used to obtain the second rotation angle value based on the second rotation angle.

[0089] Exemplarily, the first transmission assembly 3 includes a third transmission member 31 and a fourth transmission member 32. The first transmission member 1, the second transmission member 2 and the third transmission member 31 are reduction gear sets that are meshed in sequence, such as spur gears or helical gears. The fourth transmission member 32 is a ball screw, and the nut of the ball screw is rigidly connected to the piston 4.

[0090] Specifically, the transmission ratio of the first transmission member 1 and the second transmission member 2 can be selected according to the theoretical movement stroke of the piston 4, and then the measurement stroke can be designed according to the transmission ratio to ensure that the measurement stroke is greater than the theoretical movement stroke of the piston 4, thereby ensuring the accuracy of the absolute position measurement of the piston 4.

[0091] Exemplarily, the first magnet 7 is connected to the rotating shaft of the first transmission member 1, and the second magnet 8 is connected to the transmission shaft of the second transmission member 2. The first magnet 7 and the second magnet 8 are both permanent magnets; the first detection component 5 is arranged corresponding to the first magnet 7, and the second detection component 6 is arranged corresponding to the second detection component. The first detection component 5 and the second detection component 6 are both angle detection chips.

[0092] It is worth noting that the EMB piston absolute position detection device of the present invention adopts two sets of magnets installed on the gear set, and collects the angle signals of the two gears in a non-contact manner based on the principle of magnetic resistance, thereby obtaining the absolute position of the piston 4 with high precision, avoiding the accuracy attenuation caused by mechanical wear in traditional contact detection. At the same time, since the first magnet 7 and the second magnet 8 are directly installed on the shaft end of the gear, the influence of the high temperature environment on the position of the piston 4 is avoided, and the detection accuracy can be improved to within ±0.001mm, meeting the stringent requirements for millimeter-level displacement control in vehicle braking.

[0093] In an optional embodiment, the first transmission member 1 is coaxially connected to the rotor of the brake motor 9, and the first magnet 7 is also used to obtain the rotation angle of the rotor of the brake motor 9 to obtain the rotor rotation angle; the first detection component 5 is also used to obtain the rotor rotation angle value based on the rotor rotation angle.

[0094] For example, one end of the rotating shaft of the first transmission member 1 is connected to the first detection assembly 5, and the other end of the rotating shaft of the first transmission member 1 is coaxially connected to the rotor of the brake motor 9 via a coupling. The torque of the brake motor 9 is decelerated and amplified before being transmitted to the next-stage transmission assembly through the reduction gear set formed by the first transmission member 1 and the second transmission member 2. Therefore, the rotation angle of the first transmission member 1 is also the rotation angle of the rotor of the brake motor 4. In addition to being used to detect the absolute position of the piston 4, the rotation angle value of the first transmission member 1 can also be used to measure the rotation angle of the rotor of the brake motor 9. This eliminates the need for an additional motor rotor position sensor, streamlining the structure of the entire EMB system.

[0095] In an optional embodiment, the EMB piston absolute position detection device further includes: a control processing component 10, wherein the control processing component 10 is respectively connected to the first detection component 5, the second detection component 6 and the brake motor 9, for respectively obtaining the rotor rotation angle value, the first rotation angle value and the second rotation angle value, and obtaining the first incremental angle signal and the second incremental angle signal according to the first rotation angle value and the second rotation angle value; then obtaining the absolute angle value according to the first incremental angle signal and the second incremental angle signal, and obtaining the absolute position of the piston according to the absolute angle value; finally, controlling the brake motor 9 according to the absolute position of the piston 4.

[0096] Exemplarily, the control processing component 10 is a PCB (Printed Circuit Board), which is arranged parallel to the first transmission member 1 and the second transmission member 2, and is used to obtain an absolute angle value based on the rotation angle value, and then obtain the displacement of the piston 4 based on the absolute angle value and the parameters of each transmission member, such as the reduction ratio of the reduction gear set and the lead of the ball screw.

[0097] Furthermore, the three-phase terminals of the brake motor 9 are connected to the PCB circuit board by welding. By measuring the rotation angle of the rotor of the brake motor 9, the current loop, speed, position loop, weak magnetic field, etc. of the brake motor 9 can be controlled through the control processing component 10.

[0098] Exemplarily, the first detection component 5 and the second detection component 6 are both angle detection chips, which can adopt Allegro's A1338 chip; the control processing component 10 is a processing and computing chip, which can adopt NXP's S32K344 chip, and the angle detection chip and the processing and computing chip communicate through a SENT interface or an SPI interface. C language programming is used on the processing and computing chip to realize the detection of the absolute angle of the rotor of the brake motor 9 and the absolute position of the piston 4 through a software algorithm.

[0099] The EMB piston absolute position detection device, through the collaborative design of dual transmission components, magnets, and detection components, simplifies sensor layout and reduces installation precision requirements. By eliminating the need for complex calibration procedures, the risk of cumulative error is reduced. Furthermore, the device is compatible with existing brake motors, significantly lowering manufacturing costs and maintenance.

[0100] Example 3

[0101] like Figure 4 and Figure 5 As shown, Figure 5 3 is a signal diagram of the EMB piston absolute position detection device provided in an embodiment of the present invention.

[0102] The working principle of the EMB piston absolute position detection method and detection device of the present invention is as follows:

[0103] The first detection component 5 outputs a first rotation angle detection value A11 and a first rotation angle redundancy value A12 to the control processing component 10 based on the first rotation angle A01, and the second detection component 6 outputs a second rotation angle detection value A21 and a second rotation angle redundancy value A22 to the control processing component 10 based on the second rotation angle A02. The first rotation angle detection value A11 and the first rotation angle redundancy value A12 are mutually redundant, and the second rotation angle detection value A21 and the second rotation angle redundancy value A22 are mutually redundant. The first detection component 5 and the second detection component 6 are provided with different power supplies and signal processing circuits, and are respectively provided with different physical interfaces for connecting to the control processing component 10. By performing redundancy checks on the mutually redundant angle values, redundant check results A1D for the first rotation angle detection value A11 and the first rotation angle redundancy value A12, and redundant check results A2D for the second rotation angle detection value A21 and the second rotation angle redundancy value A22 are obtained, respectively, to determine the validity of the signals and detect their consistency.

[0104] Because both the first rotation angle detection value A11 and the first rotation angle redundancy value A12 vary periodically between 0 and 360°, meaning that without incremental calculation, their angle values can only reflect relative position changes within a single rotation, incremental calculation is required to accumulate the angle changes to produce the first incremental angle measurement signal A110 and the first incremental angle redundancy signal A120, respectively. Similarly, the second rotation angle detection value A21 and the second rotation angle redundancy value A22 are incrementally calculated to produce the second incremental angle measurement signal A210 and the second incremental angle redundancy signal A220, respectively. Incremental calculation allows for the measurement of multiple rotation angles, and the maximum number of measurable rotations is related to the transmission ratio between the various transmission components.

[0105] A first absolute angle difference value A121 is obtained based on the difference between the first incremental angle measurement signal A110 and the second incremental angle measurement signal A210. Based on the first absolute angle difference value A121 and the transmission ratio between the first transmission member 1 and the second transmission member 2, a first absolute angle value A1 of the first transmission member 1 can be obtained. Similarly, a second absolute angle difference value A122 is obtained based on the difference between the first incremental angle redundancy signal A120 and the second incremental angle redundancy signal A220. Based on the transmission ratio between the first transmission member 1 and the second transmission member 2, a second absolute angle value A2 of the first transmission member 1 can be obtained. The first absolute angle value A1 and the second absolute angle value A2 are absolute angle signals obtained from different signal sources.

[0106] In addition, by performing normalization calculation on the second rotation angle A02 output by the second detection component 6, a first normalized rotation angle signal A31 and a second normalized rotation angle signal A32 that are consistent with the first rotation angle detection value A11 and the first rotation angle redundancy value A12 output by the first detection component 5 can be obtained. The normalized rotation angle signal can also be used for redundancy check, and the redundant check result A13D1 of the first rotation angle detection value A11 and the first normalized rotation angle signal A31, and the redundant check result A13D2 of the second rotation angle detection value A22 and the second normalized rotation angle signal A32 are obtained respectively.

[0107] The following is an example of a gear set tooth ratio z1:z2:z3=16:26:48, a ball screw lead s=5 mm, a first transmission member 1 and a second transmission member 2 tooth ratio (transmission ratio) m=16:26=8:13, and a total transmission ratio i′=(26 / 16)*(48 / 26)=3 (the total transmission ratio can temporarily ignore the transmission ratio of the ball screw). Among them, z1 is the number of teeth of the first transmission member 1; z2 is the number of teeth of the second transmission member 2; z3 is the number of teeth of the third transmission member 31; m is the tooth ratio of the first transmission member 1 to the second transmission member 2; n is the tooth ratio i2 of the second transmission member 2 to the third transmission member 31; i′ is the total transmission ratio between the first transmission member 1, the second transmission member 2 and the third transmission member 31, i′=m*n; P is the absolute position of the piston 4; R is the absolute position measurement range of the piston 4; s is the lead of the fourth transmission member 32 (ball screw).

[0108] like Figure 2 As shown, since the tooth ratio m between the first transmission member 1 and the second transmission member 2 is 8, the first rotation angle detection value A11 is repeated after 13 cycles, and the second rotation angle detection value A21 is repeated after 8 cycles, that is, the maximum measurable absolute angle range is 360°*13=4680°; and according to the lead s=5mm of the ball screw, the absolute position measurement range R of the piston 4 can be obtained as R=(4680° / 360° / 3)*5mm=21.667mm.

[0109] like Figure 4 As shown, the first rotation angle detection value A11 is incrementally calculated to obtain a first incremental angle measurement signal A110, and the second rotation angle detection value A21 is incrementally calculated to obtain a second incremental angle measurement signal A210. The first absolute angle value A1 is then calculated based on the difference between the first incremental angle measurement signal A110 and the second incremental angle measurement signal A210, and its expression is:

[0110] A121=A110-A210;

[0111] A1=A121*j;

[0112] j = z2 / (z2-z1);

[0113] Among them, j is the transmission coefficient.

[0114] Similarly, the first rotation angle redundancy value A12 is incrementally calculated to obtain a first incremental angle redundancy signal A120, and the second rotation angle redundancy value A22 is incrementally calculated to obtain a second incremental angle redundancy signal A220. The second absolute angle value A2 is then calculated based on the difference between the first incremental angle redundancy signal A120 and the second incremental angle redundancy signal A220, and its expression is:

[0115] A122=A120-A220;

[0116] A2=A122*z2 / (z2-z1);

[0117] Finally, according to the first absolute angle value A1 and the second absolute angle value A2, the absolute position P of the piston 4 is obtained, which is expressed as follows:

[0118] P = (A / 360 / i)*s;

[0119] P1=(A1 / 360 / i)*s;

[0120] P2=(A2 / 360 / i)*s;

[0121] Wherein, P is the absolute position of the piston 4; A is the absolute angle value; P1 is the absolute position of the piston 4 obtained according to the first absolute angle value A1; and P2 is the absolute position of the piston 4 obtained according to the second absolute angle value A2.

[0122] It can be understood that after the absolute position P of the piston 4 is obtained, high-precision closed-loop control of the piston position can be performed on the EMB system.

[0123] For example, the measurement accuracy of the first detection assembly 5 and the second detection assembly 6 are both 0.1°. When the first gear rotates 0.1°, the displacement L of the piston is:

[0124] L=(0.1° / 360° / 3)*5mm=0.000462963;

[0125] Where L is the displacement of the piston.

[0126] Therefore, the measurement accuracy can reach ±0.001mm.

[0127] It is worth noting that the angle of the second transmission member 2 can be normalized to the angle of the first transmission member 1 through normalization calculation to improve the detection accuracy. The second rotation angle detection value A21 is normalized to obtain the rotation angle signal of the first transmission member 1, which is expressed as follows:

[0128] A31=MOD(A21 / z2 / z1,360);

[0129] Wherein, MOD is the modulo function; A31 is the first normalized rotation angle signal.

[0130] Similarly, the second rotation angle redundancy value A22 is normalized and calculated to obtain the rotation angle signal of the second transmission member 2, which is expressed as follows:

[0131] A32=MOD(A22 / z2 / z1,360);

[0132] Among them, A32 is the second normalized rotation angle signal.

[0133] The EMB piston absolute position detection device of the present invention also includes multiple redundancy check and fault diagnosis modules. For example, redundancy check is performed on the first rotation angle detection value A11 and the first rotation angle redundancy value A12, resulting in a redundancy check result of A1D; redundancy check is performed on the second rotation angle detection value A21 and the second rotation angle redundancy value A22, resulting in a redundancy check result of A2D; redundancy check is performed on the first rotation angle detection value A11 and the first normalized rotation angle signal A31, resulting in a redundancy check result of A13D1; and redundancy check is performed on the second rotation angle detection value A21 and the second normalized rotation angle signal A32, resulting in a redundancy check result of A13D2. These multiple redundancy check and fault diagnosis modules ensure signal accuracy and reliability, improving system reliability and functional safety.

[0134] Specifically, multiple redundancy check and fault diagnosis modules perform real-time detection work respectively, and their working principles are as follows:

[0135] 1) When no abnormality is found in the redundant check result A1D between the first rotation angle detection value A11 and the first rotation angle redundant value A12: taking the first rotation angle detection value A11 as the rotor angle of the brake motor 9 for controlling the brake motor 9;

[0136] 2) When no abnormality is found in the redundant check result A1D between the first rotation angle detection value A11 and the first rotation angle redundant value A12 and the redundant check result A13D1 between the first rotation angle detection value A11 and the first normalized rotation angle signal A31: take the first rotation angle detection value A11 as the rotor angle of the brake motor 9, take the absolute position P1 obtained according to the first absolute angle value A1 as the absolute position of the system, and take the speed value SP1 obtained according to the first absolute angle value A1 as the speed of the system;

[0137] 3) When a redundant check result A1D between the first rotation angle detection value A11 and the first rotation angle redundant value A12 finds an abnormality, but a redundant check result A13D1 between the first rotation angle detection value A11 and the first normalized rotation angle signal A31 finds no abnormality: the first rotation angle detection value A11 signal is taken as the rotor angle of the brake motor 9, the first absolute angle value A1 is taken as the absolute angle of the system, the absolute position P1 obtained according to the first absolute angle value A1 is taken as the absolute position of the system, the speed value SP1 obtained according to the first absolute angle value A1 is taken as the speed of the system, and at the same time, a signal fault is detected in the first rotation angle redundant value A12;

[0138] 4) When both the redundant check result A1D between the first rotation angle detection value A11 and the first rotation angle redundant value A12 and the redundant check result A13D1 between the first rotation angle detection value A11 and the first normalized rotation angle signal A31 are abnormal, but the redundant check result A13D2 between the second rotation angle detection value A21 and the second normalized rotation angle signal A32 is not abnormal: the first rotation angle redundant value A12 signal is used as the angle of the motor rotor position sensor, A2 is used as the absolute angle A of the system, the absolute position P2 obtained according to the second absolute angle value A2 is used as the absolute position of the system, the speed value SP2 obtained according to the second absolute angle value A2 is used as the speed of the system, and at the same time, it is detected that the first rotation angle detection value A11 is faulty;

[0139] 5) When the redundant check result A1D between the first rotation angle detection value A11 and the first rotation angle redundant value A12, the redundant check result A13D1 between the first rotation angle detection value A11 and the first normalized rotation angle signal A31, and the redundant check result A13D2 between the second rotation angle detection value A21 and the second normalized rotation angle signal A32 are all abnormal: at this time, there is no available angle signal, and it is detected that the first rotation angle detection value A11, the first rotation angle redundant value A12, the second rotation angle detection value A21, and the second rotation angle redundant value A22 are all faulty, the system cannot operate, and enters a fault state;

[0140] 6) The redundant check result A2D between the second rotation angle detection value A21 and the second rotation angle redundant value A22 is only used for quick diagnosis of the second rotation angle detection value A21 and the second rotation angle redundant value A22. Due to the existence of the redundant check result A13D1 of the first normalized rotation angle signal A31 and the redundant check result A13D2 between the second rotation angle detection value A21 and the second normalized rotation angle signal A32, the redundant check result A2D between the second rotation angle detection value A21 and the second rotation angle redundant value A22 can be omitted when streamlining the system.

[0141] The above-mentioned redundant check and fault diagnosis modules ensure the accuracy and reliability of the signal, thereby improving the reliability and functional safety of the system.

[0142] Furthermore, the speed value of the brake motor 9 can be obtained based on the absolute angle. When the EMB system is controlled, the position of the piston 4 is used as the target for control. The target speed output by the brake motor 9 is closed-loop controlled based on the target position and actual position of the piston 4, and then closed-loop controlled with the actual speed of the brake motor 9, and the target current is output for current closed-loop control.

[0143] Notably, redundant calibration enhances system reliability and cost advantages, reducing hardware complexity and deployment costs by over 30% while ensuring functional safety levels. Furthermore, piston position detection response time can be shortened to less than 0.1ms in emergency braking or high-frequency energy recovery scenarios, resolving the control lag caused by data loss in traditional incremental encoders and significantly improving the dynamic stability of the braking system.

[0144] Furthermore, this invention expands application compatibility. The detection device supports standardized interfaces and multi-platform integration, adapting to different EMB actuator models and providing a technical foundation for the large-scale application of wire-controlled brake systems. Therefore, with its high precision, strong anti-interference ability, and low cost, this invention promotes the dual upgrade of braking safety and energy efficiency management for intelligent driving vehicles, and supports the continued development of the new energy vehicle industry towards high integration and high reliability.

[0145] It should be noted that, in this document, relational terms such as first and second are used solely to distinguish one entity or operation from another, and do not necessarily require or imply any actual relationship or order between these entities or operations. Furthermore, the terms "comprise," "include," or any other variations thereof are intended to encompass non-exclusive inclusion, such that an article or device comprising a list of elements includes not only those elements but also other elements not explicitly listed. Without further limitation, an element defined by the phrase "comprising a..." does not preclude the presence of additional identical elements in the article or device comprising the element. Terms such as "connected" or "connected" are not limited to physical or mechanical connections but may include electrical connections, whether direct or indirect. References to orientations or positional relationships, such as "upper," "lower," "left," and "right," are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate description and simplify the description of the present invention. They do not indicate or imply that the device or element referred to must have, be constructed, or operate in a specific orientation, and are therefore not to be construed as limiting the present invention.

[0146] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A method for detecting the absolute position of an EMB piston, characterized in that: include: Step 1: Obtain a first rotation angle and a second rotation angle, respectively, wherein the first rotation angle is the rotation angle of the first transmission member, and the second rotation angle is the rotation angle of the second transmission member; the first transmission member and the second transmission member are in transmission connection with each other, and the second transmission member and the piston are in transmission connection via the first transmission assembly; Step 2: obtaining a first rotation angle value according to the first rotation angle, and obtaining a second rotation angle value according to the second rotation angle; Step 3: Obtain a first incremental angle signal and a second incremental angle signal respectively through incremental calculation according to the first rotation angle value and the second rotation angle value, and obtain an absolute angle value according to the first incremental angle signal and the second incremental angle signal; Step 4: Obtain the absolute position of the piston according to the absolute angle value.

2. The EMB piston absolute position detection method according to claim 1, characterized in that: The first magnet is connected to the first transmission member and is used to obtain a first rotation angle, and the first detection component is used to obtain the first rotation angle value according to the first rotation angle; The second magnet is connected to the second transmission member and is used to obtain a second rotation angle. The second detection component is used to obtain the second rotation angle value according to the second rotation angle.

3. The EMB piston absolute position detection method according to claim 1, characterized in that: The incremental calculation includes: The angle increments of the first rotation angle value changing over time are accumulated to obtain a first incremental angle signal; the angle increments of the second rotation angle value changing over time are accumulated to obtain a second incremental angle signal.

4. The EMB piston absolute position detection method according to claim 1, characterized in that: The first rotation angle value includes a first rotation angle detection value and a first rotation angle redundancy value, wherein the first rotation angle redundancy value is used to perform redundancy check on the first rotation angle detection value; The second rotation angle value includes a second rotation angle detection value and a second rotation angle redundant value, and a normalization calculation is performed according to the second rotation angle detection value and the second rotation angle redundant value to obtain a first normalized rotation angle signal and a second normalized rotation angle signal respectively; The first normalized rotation angle signal is used to perform redundancy check on the first rotation angle detection value, and the second normalized rotation angle signal is used to perform redundancy check on the first rotation angle redundant value.

5. The EMB piston absolute position detection method according to claim 4, characterized in that: The normalization calculation includes: According to the second rotation angle detection value and the transmission ratio between the first transmission member and the second transmission member, a remainder is taken to obtain a first normalized rotation angle signal, which is expressed as follows: A31=MOD(A21*m,360); A31 is the first normalized rotation angle signal; MOD is the modulo function; A21 is the second rotation angle detection value; m is the transmission ratio between the first transmission member and the second transmission member; According to the second rotation angle redundancy value and the transmission ratio between the first transmission member and the second transmission member, a remainder is taken to obtain a second normalized rotation angle signal, which is expressed as follows: A32=MOD(A22*m,360); A32 is the second normalized rotation angle signal; A22 is the second rotation angle redundant value.

6. The EMB piston absolute position detection method according to claim 4, characterized in that: Obtaining an absolute angle value according to the first incremental angle signal and the second incremental angle signal, comprising: An absolute angle difference is obtained according to the difference between the first incremental angle signal and the second incremental angle signal. The absolute angle value is obtained according to the absolute angle difference, and the expression thereof is: A121=A110-A210; A1=A121*j; Among them, A121 is the first absolute angle difference; A110 is the first incremental angle measurement signal; A210 is the second incremental angle measurement signal; A1 is the first absolute angle value; and j is the transmission coefficient.

7. The EMB piston absolute position detection method according to claim 4, characterized in that: Obtaining the absolute position of the piston according to the absolute angle value includes: Obtaining the absolute position of the piston according to the absolute angle value and a total transmission ratio between the first transmission member, the second transmission member, and the first transmission assembly; wherein the first transmission assembly includes a third transmission member and a fourth transmission member; The absolute position of the piston is expressed as: P = (A / 360 / i′)*s; i′=m*n; P is the absolute position of the piston; A is the absolute angle value; i′ is the total transmission ratio between the first transmission member, the second transmission member and the first transmission assembly; n is the transmission ratio between the second transmission member and the third transmission member; s is the transmission coefficient of the fourth transmission member.

8. An EMB piston absolute position detection device, characterized in that: The EMB piston absolute position detection method according to any one of claims 1 to 7, wherein the device comprises: a first transmission member, a first magnet, a first detection assembly, a second transmission member, a second magnet, a second detection assembly, a first transmission assembly, and a piston, wherein the first transmission member, the second transmission member, the first transmission assembly, and the piston are sequentially connected in a transmission manner; The first magnet is used to obtain the rotation angle of the first transmission member to obtain a first rotation angle; the first detection component is used to obtain a first rotation angle value according to the first rotation angle; The second magnet is used to obtain the rotation angle of the second transmission member to obtain a second rotation angle; the second detection component is used to obtain a second rotation angle value according to the second rotation angle.

9. The EMB piston absolute position detection device according to claim 8, characterized in that: The first transmission member is coaxially connected to the rotor of the brake motor. The first magnet is also used to obtain the rotation angle of the rotor of the brake motor to obtain the rotor rotation angle. The first detection component is also used to obtain the rotor rotation angle value according to the rotor rotation angle.

10. The EMB piston absolute position detection device according to claim 9, characterized in that: Also includes: A control processing component, wherein the control processing component is respectively connected to the brake motor, the first detection component and the second detection component, and is used to respectively obtain the rotor rotation angle value, the first rotation angle value and the second rotation angle value, and obtain a first incremental angle signal and a second incremental angle signal according to the first rotation angle value and the second rotation angle value; then obtain an absolute angle value according to the first incremental angle signal and the second incremental angle signal, and obtain the absolute position of the piston according to the absolute angle value; finally, the brake motor is controlled according to the absolute position of the piston.

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