An integrated variable feel pedal feel simulator and control method

Abstract

The present application relates to a kind of integrated variable feeling pedal feeling simulator and control method, to solve the problem of low sensitivity of existing pedal feeling simulation.The application uses mechanical structure to generate first reaction force, electromagnetic structure generates second reaction force, when the absolute value of the difference between actual feedback pedal force corresponding to first reaction force and pedal force is greater than the set pedal force threshold value, electric control unit controls electromagnetic structure to generate second reaction force, and adjusts current to control second reaction force, until the absolute value of the difference between actual feedback pedal force corresponding to the sum of first reaction force and second reaction force and pedal force is less than or equal to the set pedal force threshold value;And when pedal displacement is not 0, electric control unit always adjusts current according to pedal force, realizes pedal feeling self-adapting adjustment, and when electromagnetic structure fails to power off, mechanical structure can realize pedal feeling simulation, ensure system function safety, and structure integration saves installation space.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pedal feeling simulator, and in particular to an integrated variable feeling pedal feeling simulator and a control method. BACKGROUND

[0002] The brake system is an important execution mechanism of intelligent vehicle motion control and is a key to safe driving of vehicles. The traditional brake system cannot meet the requirements of intelligent vehicles on the brake system because it cannot realize active braking, precise control of brake pressure and other functions. At present, the brake-by-wire system is gradually replacing the traditional brake system because of its characteristics of "rapid pressure building and precise pressure control". In the brake-by-wire system, the electronic control unit ECU receives the driver's braking intention signal collected by the pedal sensor and controls the brake actuator to output brake force after processing.

[0003] Because the brake-by-wire system realizes full decoupling of the pedal and the master cylinder, a pedal feeling simulator needs to be added to the brake-by-wire system to provide brake pedal feeling feedback for the driver. The existing pedal feeling simulator can be divided into active and passive types according to the pedal force simulation mode. At present, the pedal feeling simulator of the brake-by-wire system of the vehicle is mostly a passive pedal feeling simulator, which has the problems of single pedal feeling simulation and inability to flexibly change the pedal feeling according to the driving conditions. The active pedal feeling simulator mostly uses a motor to realize different pedal feeling simulation, but lacks redundant structure, cannot guarantee the functional safety of the system, has safety hazards, and has a complex structure, high cost and is not easy to realize mass production. Therefore, the pedal feeling simulator has become a problem to be solved in the field of brake-by-wire systems. SUMMARY

[0004] In order to solve the above problems in the prior art, the purpose of the present application is to provide an integrated variable feeling pedal feeling simulator and a control method, which adopts a combination of electromagnetic structure and mechanical structure for integrated design, reduces the overall volume and mass of the simulator, and the electromagnetic structure can adaptively simulate different pedal feelings by changing the size of the current of the electromagnetic coil in real time according to the real-time pedal force, improving the response speed of the pedal simulator. At the same time, the mechanical structure can be used as a backup for the electromagnetic structure, which can still well realize pedal feeling simulation when the electromagnetic structure fails due to power failure, etc., without distracting the driver and causing misoperation. In order to achieve the above technical purpose, the specific technical scheme is as follows.

[0005] In the first aspect, the present application provides an integrated variable feeling pedal feeling simulator, wherein the pedal feeling simulator comprises a cylinder body and an electronic control unit ECU.

[0006] The electromagnetic structure and the mechanical structure are integrated in the cylinder body from the bottom to the opening, the mechanical structure generates a first reaction force, and the electromagnetic structure generates a second reaction force.

[0007] When the absolute value of the difference between the actual feedback pedal force corresponding to the first reaction force and the pedal force is greater than the set pedal force threshold, the electronic control unit ECU controls the electromagnetic structure to generate a second reaction force, and adjusts the second reaction force by adjusting the current until the absolute value of the difference between the actual feedback pedal force corresponding to the sum of the first reaction force and the second reaction force and the pedal force is less than or equal to the set pedal force threshold;

[0008] And when the pedal displacement does not return to 0, the electronic control unit ECU always adjusts the current according to the pedal force to realize adaptive adjustment of the pedal feeling.

[0009] In the above technical solution, in one embodiment of the mechanical structure, the first piston (4) and the second piston (8) are coaxially sleeved, and the free lengths of the first elastic element (5), the second elastic element (6) and the third elastic element (7) are sequentially shortened between the second side end face of the first piston (4) and the second side end face of the second piston (8); the first side end face of the first piston (4) is used for being connected with the pedal push rod (2), and the first side end face of the second piston (8) is provided with a shoulder for connecting one end of the fourth elastic element (9), and the other end of the fourth elastic element (9) is abutted with the electromagnetic structure, so that the fourth elastic element (9) can be deformed when the pedal feeling simulator generates a reaction force;

[0010] The mechanical structure provides three types of braking conditions through the combination of elastic elements, which are low-intensity braking condition, medium-intensity braking condition and high-intensity braking condition;

[0011] In the low-intensity braking condition, the first elastic element (5) is compressed and connected in series with the fourth elastic element (9), and at this time, the second elastic element (6) and the third elastic element (7) are not in contact with the first piston (4);

[0012] In the medium-intensity braking condition, the first elastic element (5) and the second elastic element (6) are connected in parallel, and are connected in series with the fourth elastic element (9);

[0013] In the high-intensity braking condition, the first elastic element (5), the second elastic element (6) and the third elastic element (7) are connected in parallel, and are connected in series with the fourth elastic element (9).

[0014] In the above technical solution, in one embodiment of the electromagnetic structure, the electromagnetic structure includes an electromagnetic coil (15) and an armature (11);

[0015] When the armature (11) is in the initial position, one end is located at the bottom of the cylinder, and the other end abuts with one end of the fourth elastic element (9) of the mechanical structure, and the other end of the fourth elastic element (9) is located on the mechanical structure;

[0016] The electromagnetic coil (15) is connected with the electronic control unit ECU (16) through a wire passing through the breathing hole (13) at the bottom of the cylinder (14);

[0017] When the absolute value of the difference between the actual feedback pedal force corresponding to the first reaction force and the pedal force is greater than the set pedal force threshold, or when the pedal displacement is 0, the electronic control unit ECU (16) controls the electromagnetic coil (15) to be powered and adjusts the current, so that the armature (11) moves, thereby realizing adaptive adjustment of pedal feeling simulation; when the pedal displacement is 0, the electronic control unit ECU (16) makes the armature (11) return to the initial position.

[0018] In the above technical solution, a limit switch (12) is arranged on the inner wall of the bottom of the cylinder (14), and is connected with the electronic control unit ECU (16) through a wire (17) passing through the breathing hole (13) at the bottom of the cylinder (14), for detecting whether the armature (11) returns to the initial position when the pedal displacement is 0.

[0019] In an embodiment of the above technical solution, the electronic control unit ECU (16) judges the brake working condition category according to the pedal displacement rate:

[0020] If the pedal displacement rate is less than a first threshold, it is determined to be a low-intensity brake working condition;

[0021] If the pedal displacement rate is greater than or equal to the first threshold and less than a second threshold, it is determined to be a medium-intensity brake working condition;

[0022] If the pedal displacement rate is greater than or equal to the second threshold and less than a third threshold, it is determined to be a high-intensity brake working condition.

[0023] In an embodiment of the above technical solution, the pedal displacement rate is obtained through a pedal displacement sensor (19);

[0024] The pedal displacement sensor (19) is located on the push rod (2) and is connected with the electronic control unit ECU (16) through a wire (17); wherein the push rod (2) is used to connect the pedal (1) and the mechanical structure;

[0025] The pedal force is obtained through a pedal pressure sensor (20);

[0026] The pedal pressure sensor (20) is located on the pedal (1) and is connected with the electronic control unit ECU (16) through a wire (17).

[0027] In an embodiment of the above technical solution, according to the brake working condition category and the power-on current in the electromagnetic coil (15), the actual feedback pedal force is calculated as follows:

[0028]

[0029] When the brake working condition category is a low-intensity brake working condition:

[0030]

[0031] When the brake working condition category is a medium-intensity brake working condition:

[0032]

[0033] When the brake working condition category is a high-intensity brake working condition:

[0034]

[0035] In the formula, k1, k2, k3 and k4 are compression coefficients of the first elastic element (5), the second elastic element (6), the third elastic element (7) and the fourth elastic element (9) respectively; x is the displacement of the pedal push rod; a is the lever ratio of the brake pedal (1); F m is the electromagnetic force generated by the electromagnetic coil (15).

[0036] In an embodiment of the above technical solution, a limiting sleeve (10) is arranged on the inner wall of the bottom of the cylinder body (14) and located between the electromagnetic coil (15) and the armature (11) to limit the moving distance of the armature (11).

[0037] In an embodiment of the above technical solution, the pedal feeling simulator further comprises a cylinder cover (3) connected and installed with the cylinder body (14) through bolts (18), the cylinder cover (3) and the cylinder body (14) have breathing holes, and the cylinder cover (3) further has a central through hole through which the push rod (2) is connected with the mechanical structure and the pedal (1).

[0038] In a second aspect, the application provides a control method of an integrated variable-feeling pedal feeling simulator, an electronic control unit ECU simultaneously acquires pedal force and pedal displacement rate; when the electromagnetic force is 0, the actual feedback pedal force is first calculated according to the pedal displacement rate, and when the absolute value of the difference between the actual feedback pedal force of the pedal feeling simulator and the pedal force is greater than a set pedal force threshold value, the electronic control unit ECU controls the electromagnetic coil to generate an electromagnetic force, and adjusts the electromagnetic force by adjusting the current of the electromagnetic coil, so as to adjust the actual feedback pedal force of the pedal feeling simulator, until the absolute value of the difference between the actual feedback pedal force and the pedal force is less than or equal to the pedal force threshold value; and when the pedal displacement has not returned to 0, the electronic control unit ECU always adjusts the current according to the pedal force, to realize self-adaptive adjustment of the pedal feeling.

[0039] The application has the following technical effects:

[0040] 1. The pedal feeling simulator integrates electromagnetic structure and mechanical structure in a cylinder, and only occupies the space of a cylinder from the overall external view. The structural integration can save installation space and improve economic benefits.

[0041] 2. The ECU controls the size and direction of the current inside the electromagnetic coil, so that the electromagnetic force generated by the electromagnetic coil changes in size and direction, and then controls the movement direction of the armature. According to the pedal force, the variable pedal feeling simulation is realized. Compared with the active pedal feeling simulator using a motor, the radial size is small, and the structure is simple. Because the electromagnetic structure is in the cylinder, the anti-impact and vibration ability is strong, so that the pedal feeling simulator reliability is enhanced.

[0042] 3. When the pedal feeling simulator fails due to power failure, the pedal feeling simulation can be realized by the mechanical structure. The mechanical structure uses three-stage springs (different stiffness) to simulate pedal feeling, improves pedal feeling sensitivity, and realizes pedal feeling simulation function redundancy through mechanical structure. In the case of electromagnetic structure failure, it can also provide a real pedal feeling, which can ensure the functional safety of the system. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0044] Figure 1 The structural diagram of an integrated variable pedal feeling simulator in an embodiment;

[0045] Figure 2 The structural diagram of a cylinder and a cylinder cover in an embodiment;

[0046] Figure 3 The working flow chart of the control method of the integrated variable pedal feeling simulator in an embodiment;

[0047] Figure 4 The pedal feeling feedback force diagram provided by the pedal feeling simulator in different modes in an embodiment;

[0048] As shown in the figure: 1. Brake pedal, 2. Push rod, 3. Cylinder cover, 4. First piston, 5. First elastic element, 6. Second elastic element, 7. Third elastic element, 8. Second piston, 9. Fourth elastic element, 10. Limiting sleeve, 11. Armature, 12. Limiting switch, 13. Breathing hole, 14. Cylinder body, 15. Electromagnetic coil, 16. Electronic control unit ECU, 17. Wire, 18. Bolt, 19. Pedal displacement sensor, 20. Pedal force sensor. DETAILED DESCRIPTION

[0049] In the description of the present application, it should be explained that, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrally connected; for those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0050] The terms "first", "second", "third", "fourth" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second", "third", "fourth" can explicitly or implicitly include one or more of the features.

[0051] The reaction force of the pedal feeling simulator in the prior art is limited, which affects the driver's judgment of the braking intensity, and for some technical solutions that use angular displacement to judge the braking intensity, the mechanical structure will also be loose with the use of the pedal, which will affect the sensitivity of the pedal feeling simulator, especially in the case of emergency braking, the response speed is crucial, and the pedal feeling simulator is not sensitive, which will bring safety hazards. At the same time, the use of motor structure will increase the volume of the pedal feeling simulator and increase the installation complexity of intelligent vehicles.

[0052] Based on this, the application provides an integrated variable feeling pedal feeling simulator, wherein the pedal feeling simulator comprises a cylinder body and an electronic control unit (ECU). Different from the prior art, the electromagnetic structure and the mechanical structure are integrated in the cylinder body from the bottom to the opening, and only occupy the space of one cylinder body from the overall appearance, so that the installation space is saved and the economic benefit is improved. The mechanical structure generates a first reaction force, and the electromagnetic structure generates a second reaction force. When the absolute value of the difference between the actual feedback pedal force corresponding to the first reaction force and the pedal force is greater than the set pedal force threshold value, the electronic control unit (ECU) controls the electromagnetic structure to generate the second reaction force, and adjusts the second reaction force by adjusting the current until the absolute value of the difference between the actual feedback pedal force corresponding to the sum of the first reaction force and the second reaction force and the pedal force is less than or equal to the set pedal force threshold value. And when the pedal displacement does not return to 0, the electronic control unit (ECU) always adjusts the current according to the pedal force to realize self-adaptive adjustment of the pedal feeling. Compared with the active pedal feeling simulator using a motor, the pedal feeling simulator has the advantages of small radial size, simple structure, strong anti-impact and vibration ability, high reliability and the like. In the pedal feeling simulator, when the pedal feeling simulator fails due to power failure, the pedal feeling simulation can be realized by the mechanical structure to ensure the functional safety of the system.

[0053] In order to facilitate the understanding of those skilled in the art, the embodiments of the technical scheme of the present application will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0054] Referring to Figure 1 and Figure 2 The pedal feeling simulator of the present application mainly comprises a brake pedal part, a cylinder body, an electronic control unit (ECU), a mechanical structure, an electromagnetic structure and a sensor part. In some embodiments, the brake pedal part may not be necessary for the pedal feeling simulator.

[0055] The brake pedal part comprises a brake pedal (1) and a push rod (2). The brake pedal (1) is installed below the front part of the driver, and the top end of the rotating part in the brake pedal (1) is fixed on the pedal support through a pin shaft, and the pedal support is fixed on the vehicle body. One end of the push rod (2) is hingedly connected with the brake pedal (1), the pedal push rod (2) passes through the center through hole of the simulator cylinder cover (3), and the other end is movably connected with the right side end surface of the first piston (4).

[0056] The electromagnetic structure and the mechanical structure are integrated in the cylinder (14) from the bottom to the opening, the mechanical structure generates the first reaction force, and the electromagnetic structure generates the second reaction force, and the structure is integrated to save installation space and improve economic benefits, and the overall structure has the characteristics of small radial size and simple structure compared with the active pedal feeling simulator using a motor.

[0057] The mechanical structure includes a first piston (4), a second piston (8), a first elastic element (5), a second elastic element (6), a third elastic element (7), and a fourth elastic element (9).

[0058] The first side end face of the first piston (4) is used to be connected with the pedal push rod (2), the first side end face of the second piston (8) is provided with a shoulder, and one end of the fourth elastic element (9) is connected with the shoulder, and the other end of the fourth elastic element (9) is in abutment with the electromagnetic structure, so that the fourth elastic element (9) can be deformed when the pedal feeling simulator generates the reaction force. The first piston (4) and the second piston (8) are arranged in the cylinder (14) in sequence from the cylinder opening to the cylinder bottom, and can realize axial reciprocating motion in the cylinder (14), the second side end face of the first piston (4) is provided with a shoulder, and the second side end face of the second piston is provided with a three-step structure, and the first step face, the second step face, and the third step face are arranged in sequence from large to small in cross-sectional area.

[0059] The first elastic element (5), the second elastic element (6), the third elastic element (7), and the fourth elastic element (9) are compression springs. The two ends of the first elastic element (5) are connected to the second side end face of the first piston (4) and the first step face of the second piston (8) respectively; one end of the second elastic element (6) is connected to the second step face of the second piston (8); and one end of the third elastic element (7) is connected to the third step face of the second piston (8). The second elastic element (6) is coaxially sleeved in the first elastic element (5), and the free length of the second elastic element (6) is less than the free length of the first elastic element (5); and the third elastic element (7) is coaxially sleeved in the second elastic element (6), and the free length of the third elastic element (7) is less than the free length of the second elastic element (6).

[0060] The mechanical structure provides three types of braking conditions through the combination of elastic elements, which are: low-intensity braking condition, medium-intensity braking condition, and high-intensity braking condition. In the low-intensity braking condition, the first elastic element (5) is compressed and connected in series with the fourth elastic element (9), and at this time, the second elastic element (6) and the third elastic element (7) are not in contact with the first piston (4); in the medium-intensity braking condition, the first elastic element (5) and the second elastic element (6) are connected in parallel, and are connected in series with the fourth elastic element (9); in the high-intensity braking condition, the first elastic element (5), the second elastic element (6), and the third elastic element (7) are connected in parallel, and are connected in series with the fourth elastic element (9).

[0061] The mechanical structure uses a three-section spring with different stiffness to simulate the pedal feeling, increases the range of the pedal feeling simulator, thereby improving the sensitivity, and also provides a real pedal feeling when the electromagnetic structure fails, realizes the redundancy of the pedal feeling simulation function, and ensures the functional safety of the system. In an embodiment, the three-section spring mechanical structure is used, and the pedal displacement and the pedal force have the following relationship in Table 1:

[0062]

[0063] The electromagnetic structure includes an electromagnetic coil (15) and an armature (11). When the armature (11) is in the initial position, one end is located at the bottom of the cylinder, and the other end abuts against one end of the fourth elastic element (9) of the mechanical structure, and the other end of the fourth elastic element (9) is located on the second piston (8) of the mechanical structure. The electromagnetic coil (15) is connected to the electronic control unit ECU (16) through a wire passing through the breathing hole (13) at the bottom of the cylinder (14).

[0064] When the absolute value of the difference between the actual feedback pedal force corresponding to the first reaction force and the pedal force is greater than the set pedal force threshold value, the electronic control unit ECU (16) controls the movement of the armature (11) in the electromagnetic structure, applies a second reaction force to the fourth elastic element (9), and adjusts the current to control the second reaction force until the absolute value of the difference between the actual feedback pedal force corresponding to the sum of the first reaction force and the second reaction force and the pedal force is less than or equal to the set pedal force threshold value. And when the pedal displacement is not 0, the electronic control unit ECU (16) always adjusts the current according to the pedal force, realizes the adaptive adjustment of the pedal feeling, and improves the sensitivity of the pedal feeling simulator. And because the electromagnetic structure is in the cylinder (14), it has strong anti-impact and vibration ability, so that the pedal feeling simulator has strong reliability. The adjustment of the current in the case includes size and direction. The second reaction force is the electromagnetic force generated by the electromagnetic coil (15), which is calculated using the following formula:

[0065]

[0066] F = B * I * A m F = B * I * A f F = B * I * A

[0067] The movement of the armature is determined by the absolute value of the difference between the actual feedback pedal force and the pedal force. When the absolute value of the difference is less than a threshold value, the current does not change, and the armature does not move, i.e. the current value is maintained when there is electricity, and there is no electricity when there is no electricity. When the feedback pedal force is less than the pedal force, the current is positively energized to control the armature to move away from the initial position. When the actual feedback pedal force is greater than the pedal force, the current is reversely energized to control the armature to move towards the initial position. As the pedal displacement continuously decreases, the armature continuously moves towards the initial position until the pedal displacement returns to 0 and the armature resets.

[0068] To facilitate real-time control and fault checking of the electronic control unit ECU, a limit switch (12) is arranged on the inner wall of the bottom of the cylinder body (14) and connected with the electronic control unit ECU (16) through a wire (17) passing through the breathing hole (13) at the bottom of the cylinder body (14), which is used to detect whether the armature (11) returns to the initial position when the pedal displacement is 0. Further, a limit sleeve (10) is arranged on the inner wall of the bottom of the cylinder body (14) to be located between the electromagnetic coil (15) and the armature (11), which is used to limit the moving distance of the armature (11).

[0069] As a further improvement of the above embodiment, the opening of the cylinder body (14) can be closed by the cylinder cover (3). Figure 2 A structural diagram of the cylinder body (14) and the cylinder cover (3) is given in the specification. The cylinder body (14) and the cylinder cover (3) are connected and installed by six uniformly arranged bolts (18). The cylinder cover (3) and the cylinder body (14) are respectively provided with breathing holes (13) to prevent the first piston (4) and the second piston (8) from being hindered by the reaction force generated by air compression when moving axially in the cylinder body (14). Further, the cylinder body (14) is made of 304L stainless steel material, which protects the electromagnetic structure and mechanical structure inside while effectively preventing electromagnetic coil (15) from leaking magnetic field and reducing electromagnetic force loss.

[0070] In the above embodiment, the pedal feeling simulator is further provided with a sensor part, which includes a pedal pressure sensor (20) and a pedal displacement sensor (19). The pedal pressure sensor (20) is connected to the brake pedal (1), and the pedal displacement sensor (19) is connected to the push rod (2). The pedal pressure sensor (20) is used to detect the pedal force of the driver stepping on the brake pedal, and the pedal displacement sensor (19) is used to detect the displacement amount of the push rod (2). Since it does not need to be converted like angular displacement, the pedal feeling simulator can have fast response speed, small hysteresis and good stability, so as to more accurately track the pedal changes and reflect the braking intention of the driver. The electronic control unit ECU (16) is used to receive the pedal force and pedal displacement signals in real time, calculate and control the current size and direction of the electromagnetic coil (15), and detect whether the electromagnetic structure has power failure and the like.

[0071] Figure 3 The working process of the integrated variable feeling pedal feeling simulator control method is illustrated, which includes the following steps:

[0072] Step one: the driver starts braking, and the pedal displacement sensor (19) and the pedal pressure sensor (20) collect pedal displacement information and pedal force information respectively.

[0073] Step two: the electronic control unit ECU (16) solves the pedal displacement rate according to the collected pedal displacement information, and compares it with the pre-set pedal displacement rate threshold value: if the pedal displacement rate is less than the first threshold value, it is judged that the low-intensity braking condition is at this time; if the pedal displacement rate is greater than the first threshold value and less than the second threshold value, it is judged that the medium-intensity braking condition is at this time; if the pedal displacement rate is greater than the second threshold value, it is judged that the high-intensity braking condition is at this time.

[0074] Step three: calculate the actual feedback pedal force F at this time, and the difference between it and the pedal force F1 collected by the pedal pressure sensor (20), and judge whether the absolute value of the difference is greater than the pre-set pedal force threshold value, if yes, enter step four; if not, enter step five.

[0075] Step four: the electronic control unit ECU (16) checks whether the electromagnetic structure has power failure and the like. If yes, enter step five; if not, adjust the current size of the electromagnetic coil (15) until the absolute value of the difference between the actual feedback pedal force F and the pedal force F1 collected by the pedal pressure sensor (20) is less than the pre-set pedal force threshold value.

[0076] Step five: the pedal displacement information collected by the pedal displacement sensor (19) is used to determine whether the pedal displacement is 0. If yes, and the electromagnetic structure does not fail to be powered off, etc., the ECU (16) changes the direction of the current of the electromagnetic coil (15) to control the armature (11) to return to the initial position, and step six is entered. If yes, but the electromagnetic structure fails to be powered off, etc., step six is directly entered. If no, step one is returned to.

[0077] Step six: when the limit switch (12) detects that the armature (11) returns to the initial position, the braking ends.

[0078] The above workflow can implement both conventional brake pedal feeling simulation and power-off failure pedal feeling simulation, and both can be divided into low-intensity braking, medium-intensity braking and high-intensity braking according to the driving conditions.

[0079] The conventional brake pedal feeling simulation process is as follows:

[0080] When the driver makes a braking operation, the information collected by the pedal displacement sensor (19) and the pedal pressure sensor (20) is transmitted to the ECU (16), and the pedal displacement rate threshold value is determined according to the pre-set pedal displacement rate threshold value. If the difference between the actual feedback pedal force F and the pedal force F1 collected by the pedal pressure sensor (20) is greater than the pre-selected pedal force threshold value, and the electromagnetic structure does not fail to be powered off, etc., the ECU (16) sends a control instruction to adjust the current of the electromagnetic coil (15) until the difference between the actual feedback pedal force F and the pedal force F1 is less than the pre-selected pedal force threshold value. When the pedal displacement sensor (19) detects that the pedal displacement is 0, the ECU (16) changes the direction of the current of the electromagnetic coil (15) to control the armature (11) to return to the initial position, and the braking ends.

[0081] Specifically, when the pedal displacement rate is less than the first threshold value, the ECU (16) determines that the low-intensity braking is in progress. At the same time, the first piston (4) is pushed by the pedal push rod (2), and then the first elastic element (5) is compressed, and is connected in series with the fourth elastic element (9). At this time, the second elastic element (6) and the third elastic element (7) are not in contact with the first piston (4). At this time, the relationship between the actual feedback pedal force F and the pedal displacement x is as follows:

[0082]

[0083] Wherein, k1 and k4 are the compression coefficients of the first elastic element (5) and the fourth elastic element (9) respectively; x is the displacement of the pedal push rod, which can be obtained by integrating the measurement value of the pedal displacement sensor; a is the lever ratio of the brake pedal (1).

[0084] When the pedal displacement rate is greater than the first threshold value and less than the second threshold value, the electronic control unit ECU (16) determines that this is a medium intensity braking. At the same time, the first piston (4) continues to move, thereby compressing the second elastic element (6), at this time the first elastic element (5) and the second elastic element (6) are in parallel. And in series with the fourth elastic element (9). At this time the third elastic element (7) is not in contact with the first piston (4). At this time the relationship between the actual feedback pedal force F and the pedal displacement x is:

[0085]

[0086] Wherein, k2 is the compression coefficient of the second elastic element (6).

[0087] Specifically, when the pedal displacement rate is greater than the second threshold value, the electronic control unit ECU (16) determines that this is a high intensity braking, the first piston (4) continues to move, thereby compressing the third elastic element (7), at this time the first elastic element (5), the second elastic element (6) and the third elastic element (7) are in parallel. And in series with the fourth elastic element (9). At this time the relationship between the actual feedback pedal force F and the pedal displacement x is:

[0088]

[0089] Wherein, k3 is the compression coefficient of the third elastic element (7).

[0090] The power-off failure pedal feeling simulation process is:

[0091] When the driver makes a braking operation, the information collected by the pedal displacement sensor (19) and the pedal pressure sensor (20) is transmitted to the electronic control unit ECU (16), and according to the pre-set pedal displacement rate threshold value, it is determined that this is a low intensity braking, medium intensity braking or high intensity braking condition. The actual feedback pedal force F is calculated by the electronic control unit ECU (16) at this time, and the pedal force F1 is collected by the pedal pressure sensor (20), if the electromagnetic structure fails at this time, the armature (11) remains stationary at the initial position, and the integrated variable feeling pedal feeling simulator becomes a passive three-stage pedal feeling simulator, at this time in the process of low intensity braking, medium intensity braking or high intensity braking, the electromagnetic force F m 0, completely relying on the combination of the first elastic element (5), the second elastic element (6), the third elastic element (7) and the fourth elastic element (9) to complete the pedal feeling simulation. When the pedal displacement sensor (19) detects that the pedal displacement is 0, the braking is over.

[0092] Reference Figure 4The broken line A and B in the figure are the corresponding relationship between the actual feedback pedal force F and the pedal displacement x when the electromagnetic force is 0 and maximum respectively. The current of the electromagnetic coil (15) is adjusted by the electronic control unit (ECU) (16), and theoretically, the pedal displacement and the real pedal force relationship curve can be adjusted in the shaded part of the figure. The broken line C, D and E in the figure are the demonstration curves of the corresponding relationship between the actual feedback pedal force F and the pedal displacement x when the braking intensity is low, medium and high respectively.

[0093] The above description is only an embodiment of the present application, and does not limit the protection scope of the present application. Any equivalent structure or equivalent process transformation, or direct or indirect application in other related system fields, which is made by using the content of the specification and drawings, is also included in the protection scope of the present application.

Claims

1. An integrated variable feel pedal feel simulator, wherein, The pedal feeling simulator comprises a cylinder body and an electronic control unit (ECU), characterized in that: Inside the cylinder body, from the bottom to the opening, are integrated in sequence an electromagnetic structure and a mechanical structure, the mechanical structure comprising a first piston (4) and a second piston (8), between the second side end face of the first piston (4) and the second side end face of the second piston (8) are coaxially sleeved a first elastic element (5), a second elastic element (6) and a third elastic element (7) with decreasing free lengths; the first side end face of the first piston (4) is used for being connected with a pedal push rod (2), the first side end face of the second piston (8) is provided with a shoulder for being connected with one end of a fourth elastic element (9), the other end of the fourth elastic element (9) abuts against the electromagnetic structure, so that the fourth elastic element (9) can be deformed when the pedal feeling simulator generates a reaction force; the electromagnetic structure comprises an electromagnetic coil (15) and an armature (11); when the armature (11) is at an initial position, one end thereof is located at the bottom of the cylinder, and the other end thereof abuts against one end of the fourth elastic element (9) of the mechanical structure, and the other end of the fourth elastic element (9) is located on the mechanical structure; the electromagnetic coil (15) is connected with the electronic control unit (ECU) (16) through a wire passing through a breathing hole (13) at the bottom of the cylinder (14); a limit switch (12) is arranged on the inner wall of the bottom of the cylinder (14) and connected with the electronic control unit (ECU) (16) through a wire (17) passing through the breathing hole (13) at the bottom of the cylinder (14), for detecting whether the armature (11) returns to the initial position when the pedal displacement is 0; a limit sleeve (10) is arranged on the inner wall of the bottom of the cylinder (14) and located between the electromagnetic coil (15) and the armature (11), for limiting the movement distance of the armature (11); The mechanical structure generates a first reaction force, and the electromagnetic structure generates a second reaction force; when the absolute value of the difference between the actual feedback pedal force corresponding to the first reaction force and the pedal force is greater than a set pedal force threshold value, the electronic control unit (ECU) controls the electromagnetic structure to generate the second reaction force, and adjusts the current to regulate the second reaction force, until the absolute value of the difference between the actual feedback pedal force corresponding to the sum of the first reaction force and the second reaction force and the pedal force is less than or equal to the set pedal force threshold value; when the absolute value of the difference between the actual feedback pedal force corresponding to the first reaction force and the pedal force is greater than the set pedal force threshold value, the electronic control unit (ECU) (16) controls the electromagnetic coil (15) to be powered and adjusts the current, so that the armature (11) moves, thereby realizing adaptive adjustment of the pedal feeling; when the pedal displacement is 0, the electronic control unit (ECU) (16) makes the armature (11) return to the initial position; when the pedal displacement does not return to 0, the electronic control unit (ECU) always adjusts the current according to the pedal force, to realize adaptive adjustment of the pedal feeling.

2. The pedal feeling simulator according to claim 1, characterized in that: The mechanical structure provides three types of braking conditions through the elastic element combination, which are respectively: a low-intensity braking condition, a medium-intensity braking condition and a high-intensity braking condition; wherein: In the low-intensity braking condition, the first elastic element (5) is compressed and connected in series with the fourth elastic element (9), and the second elastic element (6) and the third elastic element (7) are not in contact with the first piston (4); In the medium-intensity braking condition, the first elastic element (5) and the second elastic element (6) are connected in parallel, and the fourth elastic element (9) is connected in series; In the high-intensity braking condition, the first elastic element (5), the second elastic element (6), and the third elastic element (7) are connected in parallel, and the fourth elastic element (9) is connected in series.

3. The pedal feeling simulator according to claim 2, wherein: The electronic control unit ECU (16) determines the braking condition category according to the pedal displacement rate: If the pedal displacement rate is less than the first threshold value, it is determined as a low-intensity braking condition; If the pedal displacement rate is greater than or equal to the first threshold value and less than the second threshold value, it is determined as a medium-intensity braking condition; If the pedal displacement rate is greater than or equal to the second threshold value and less than the third threshold value, it is determined as a high-intensity braking condition.

4. The pedal feeling simulator according to claim 3, wherein: The pedal displacement rate is obtained by a pedal displacement sensor (19); The pedal displacement sensor (19) is located on the push rod (2) and is connected to the electronic control unit ECU (16) through a wire (17); wherein the push rod (2) is used to connect the pedal (1) and the mechanical structure; The pedal force is obtained by a pedal pressure sensor (20); The pedal pressure sensor (20) is located on the pedal (1) and is connected to the electronic control unit ECU (16) through a wire (17).

5. The pedal feeling simulator according to claim 2, wherein: According to the braking condition category and the current in the electromagnetic coil (15), the actual feedback pedal force is calculated as follows: When the braking condition category is a low-intensity braking condition: When the braking condition category is a medium-intensity braking condition: When the braking condition category is a high-intensity braking condition: wherein , , and are the compression coefficients of the first elastic element (5), of the second elastic element (6), of the third elastic element (7) and of the fourth elastic element (9), respectively; is the displacement of the pedal push rod; is the lever ratio of the brake pedal (1); is the electromagnetic force generated by the electromagnetic coil (15).

6. The pedal feeling simulator according to claim 1, wherein: The pedal feeling simulator further comprises a cylinder cover (3), the cylinder cover (3) is connected and installed with the cylinder body (14) through a bolt (18), the cylinder cover (3) and the cylinder body (14) have breathing holes, and the cylinder cover (3) further has a center through hole, through which the push rod (2) connects the mechanical structure and the pedal (1).

7. An integrated variable-feel pedal feel simulator control method characterized by, The pedal feeling simulator is any one of the pedal feeling simulators according to claims 1-6, and the steps comprise: The electronic control unit ECU simultaneously obtains the pedal force and the pedal displacement rate; When the electromagnetic force is 0, the actual feedback pedal force is first calculated according to the pedal displacement rate, and when the absolute value of the difference between the actual feedback pedal force of the pedal feeling simulator and the pedal force is greater than a set pedal force threshold value, the electronic control unit ECU controls the electromagnetic coil to generate an electromagnetic force, and adjusts the electromagnetic force by adjusting the current of the electromagnetic coil, thereby adjusting the actual feedback pedal force of the pedal feeling simulator, until the absolute value of the difference between the actual feedback pedal force and the pedal force is less than or equal to the pedal force threshold value. And in pedal displacement does not change back to 0, the electronic control unit ECU always adjust the current according to pedal force, to achieve pedal feel adaptive adjustment.

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