A method for calculating auxiliary power cylinder pressure, and an apparatus for performing the method.

Abstract

The present invention provides a corrected virtual auxiliary power cylinder pressure (p F ) is calculated. This method includes calculating at least one motor value (M M ) and a step (A) of calculating the motor value (M M ) and the virtual auxiliary power cylinder pressure (p F ) correlation model (p F (M M )) to calculate the motor value (M M ) to the virtual auxiliary power cylinder pressure (p F ) in the ESP brake system (8) by the ESP pressure sensor (36), and ESP and (C) calculating the virtual auxiliary power cylinder pressure (p F ) and the auxiliary power cylinder pressure (p ESP ) and the virtual auxiliary power cylinder pressure (p F ) to the auxiliary power cylinder pressure (p ESP ) and a step (D) of comparing the calculated deviation (Δp) with the correlation model (p F (M M and (E) correcting the

Description

[Technical Field]

[0001] The present invention relates to a method for calculating the auxiliary power cylinder pressure of an auxiliary power brake system. [Background technology]

[0002] Today's auxiliary power brake systems are superior in that they are mechanically and / or hydraulically connected to the driver. This is done via a brake pedal connected to an input rod. Through such an input rod, the driver's braking request is detected throughout the system, and the pedal sensation is realized in the form of a characteristic curve with respect to force and stroke. Pressure generation is then performed via an auxiliary power piston, which is hydraulically separated from the driver's foot. To control this pressure generation, the brake pressure generated via the auxiliary power piston is measured via a pressure sensor. Then, at the fallback level, the driver's foot is connected to the wheel brake cylinder by a muscle-operated brake cylinder, thereby allowing the driver to apply brake pressure using their foot. This allows the vehicle to remain brakeable even in the event of a malfunction.

[0003] According to Patent Document 1, an electro-hydraulic auxiliary power vehicle brake system for autonomous road vehicles is disclosed. Such an electro-hydraulic auxiliary power vehicle brake system includes two redundant auxiliary power brake pressure generators, so that during autonomous driving and in the event of a failure of one of the auxiliary power brake pressure generators, the other auxiliary power brake pressure generator can brake the vehicle without driver intervention.

[0004] Similarly, according to Patent Document 2, an electro-hydraulic auxiliary power vehicle brake system is known. In this electro-hydraulic auxiliary power vehicle brake system, the auxiliary power brake pressure generator is configured as a piston cylinder unit, which is connected to a non-pressurized brake fluid reservoir tank by a pressure limiting valve and a controllable valve. The pressure of the auxiliary power brake pressure generator is measured via a pressure sensor located on the piston cylinder unit. The pressure limiting valve prevents a pressure peak in the vehicle brake system when the suction valve of the hydraulic wheel brake of the vehicle brake system is closed while pressure is being generated by the auxiliary power brake pressure generator. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] German Patent Publication No. 102018222488 [Patent Document 2] German Patent Publication No. 102019201536 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The object of the present invention is to provide a method for calculating auxiliary power cylinder pressure that can be calculated economically. Furthermore, the object is to provide an apparatus for carrying out this method. [Means for solving the problem]

[0007] This problem is solved by a method for calculating the auxiliary power cylinder pressure having the features of claim 1. An apparatus for carrying out this method is also provided. Each cited dependent claim provides a preferred embodiment of the present invention.

[0008] The present invention provides a method for calculating the auxiliary power cylinder pressure of an auxiliary power braking system. The method includes the steps of: calculating at least one motor value of an auxiliary power cylinder motor; calculating a virtual auxiliary power cylinder pressure from this motor value using a correlation model between this motor value and a virtual auxiliary power cylinder pressure; and calculating the auxiliary power cylinder pressure using an ESP pressure sensor within an ESP braking system. Furthermore, the method includes the steps of: comparing the virtual auxiliary power cylinder pressure with the auxiliary power cylinder pressure measured by the ESP pressure sensor, taking into account the time delay between the virtual auxiliary power cylinder pressure and the auxiliary power cylinder pressure measured by the ESP pressure sensor; and modifying the correlation model according to the calculated deviation.

[0009] In this case, the auxiliary power cylinder pressure is interpreted as the pressure generated through the auxiliary power cylinder to produce braking force. In the prior art, this pressure is usually calculated via a pressure sensor located directly downstream of the auxiliary power cylinder. In this case, the virtual auxiliary power cylinder pressure is a calculated pressure, not a measured pressure. From this virtual pressure, it is assumed that this pressure corresponds to the measured pressure. However, due to the uncertainty in the calculation, a small error may exist. In the sense of the present invention, the motor value is interpreted as a measured value that depends on the operating state of the motor and changes over time. In a preferred form, the motor value is calculated using known values, so there is no need to use additional measuring sensors.

[0010] The correlation model is a model that may be configured as, for example, a mathematical function. Through this model, the auxiliary power cylinder pressure can be calculated for all motor values. This correlation model contains all factors that affect the auxiliary power cylinder pressure. Since it is difficult to consider environmental conditions such as temperature or wear of the auxiliary power type braking device, high accuracy of the calculated auxiliary power cylinder pressure can be obtained by constantly modifying the correlation model. The time delay is the time value by which the auxiliary power cylinder pressure calculated by the ESP pressure sensor is delayed in time with respect to the actual pressure or the virtual auxiliary power cylinder pressure calculated through the correlation model.

[0011] By this method, it is possible to accurately calculate the auxiliary power cylinder pressure without using a pressure sensor. Thereby, the cost for the pressure sensor can be saved, and thus an economical calculation of the auxiliary power cylinder pressure is possible.

[0012] According to a preferred embodiment of the present invention, the arrival time of the measured auxiliary power cylinder pressure of the ESP pressure sensor is measured, and using this arrival time, the time delay between the virtual auxiliary power cylinder pressure and the measured auxiliary power cylinder pressure of the ESP pressure sensor is adjusted. By calculating this arrival time, the time delay is determined, so that a more accurate calculation of the pressure difference and thus the correlation model is possible. Thereby, the virtual auxiliary power cylinder pressure is determined more accurately, and thus the control of the auxiliary power cylinder is improved. The measurement of the arrival time is regularly performed in a suitable form in order to continuously obtain high accuracy.

[0013] According to another preferred embodiment of the present invention, the arrival time of a test signal is calculated to measure the time delay. Such a test signal may include the transmission time. By comparing the reception time with the transmission time, the arrival time can be calculated in a simple form. Thereby, the arrival time is measured in a simple form independent of the braking operation, and the accuracy of the virtual auxiliary power cylinder pressure calculated thereby can be increased.

[0014] In a suitable form, torque is used as a motor value to calculate the virtual auxiliary power cylinder pressure. In this case, the torque can be measured. Similarly, this value can be calculated by the control unit. Thus, the determination of torque is easily possible.

[0015] According to a preferred embodiment, motor current is used as a motor value to calculate the virtual auxiliary power cylinder pressure. Since the motor current is known by control via the control unit, there is no need to obtain this value. Thus, the motor value can be determined in a simple form.

[0016] The object of the present invention is further solved by an apparatus for carrying out this method. This apparatus has an auxiliary power cylinder, through which an auxiliary power cylinder pressure can be generated by an auxiliary power cylinder motor, and also has an ESP pressure sensor, through which a time-delayed pressure of the auxiliary power cylinder pressure can be measured, and further has a control unit, in which a virtual auxiliary power cylinder pressure can be calculated using a correlation model between the motor value and the virtual auxiliary power cylinder pressure. Through such a calculation of the auxiliary power cylinder pressure, it is possible to provide an auxiliary power cylinder pressure measurement without a pressure sensor. Thus, by such an apparatus, the above-mentioned advantages mentioned in the above method can be obtained.

Brief Description of the Drawings

[0017] [Figure 1] It is a diagram showing an example of an auxiliary power brake device for calculating an auxiliary power cylinder pressure according to the method according to the present invention. [Figure 2] It is a diagram showing an example of a method for calculating the auxiliary power cylinder pressure of an auxiliary power brake device. [Figure 3] It is a diagram showing an example of a method for determining a time delay.

Mode for Carrying Out the Invention

[0018] Embodiments of the present invention are shown in the drawings and will be described in detail below.

[0019] Figure 1 shows one embodiment of an auxiliary power brake device 1 that attempts to calculate the auxiliary power cylinder pressure according to the method of the present invention. In this case, the auxiliary power brake device 1 has two units 4 and 8. The first unit 4 represents a substantially known auxiliary power system. Therefore, a detailed description will be omitted, but only the components relevant to the present invention will be described in detail. The first unit 4 has an auxiliary power brake pressure generator 12 equipped with an auxiliary power cylinder 16, and using this auxiliary power brake pressure generator 12, the auxiliary power cylinder pressure can be generated by the movement of an auxiliary power piston 24 via an auxiliary power cylinder motor 20. The auxiliary power cylinder motor 20 is connected to a control unit 28, and the motor 20 is controlled via this control unit 28. In this case, the auxiliary power cylinder pressure is generated at location X. At location X, an auxiliary power cylinder pressure sensor is generally located to calculate the auxiliary power cylinder pressure in the prior art. However, in this auxiliary power brake device 1, the auxiliary power cylinder pressure is calculated without using an auxiliary power cylinder pressure sensor.

[0020] The second unit 8 in this embodiment is an ESP brake system, through which brake pressure can be applied to the wheel brake 32. An ESP pressure sensor 36 is located to measure the brake pressure within the ESP brake system 8, and this ESP pressure sensor 36 is also connected to the control unit 28 to transmit the pressure to the control unit 28. The rest of the ESP brake system 8 is configured in a known form and will not be described in detail.

[0021] Figure 2 shows an example of a method for calculating the auxiliary power cylinder pressure of the auxiliary power type brake device 1 shown in Figure 1. In the first step A, the motor value of the auxiliary power cylinder motor 20 is calculated. In this case, in this example, torque M v , , ,

[0023] , ESP is calculated. Since this value is calculated standardly, no additional sensors are required for this. Optionally, the motor current of the auxiliary power cylinder motor 20 can also be calculated. Based on torque M M in the second step B, a virtual auxiliary power cylinder pressure p F is calculated. For this, the correlation p F between the virtual auxiliary power cylinder pressure p M and torque M F (M M ) is used. This correlation p F (M M ) may be values such as the transmission characteristics of the auxiliary power cylinder motor 20, the elasticity of the brake system, and the piston area.

[0022] The virtual auxiliary power cylinder pressure p F calculated in such a format is used for the auxiliary power cylinder control R, so a separate pressure sensor may be omitted. In the third step C, the pressure of the ESP pressure sensor 36 is calculated. The pressure of the ESP pressure sensor 36 is transmitted to the control unit 28. In this control unit 28, in the fourth step D, the calculated auxiliary power cylinder pressure p F is compared with the auxiliary power cylinder pressure p ESP of the ESP pressure sensor 36. Based on the fact that the auxiliary power cylinder pressure p ESP of the ESP sensor 36 is transmitted to the control unit 28 with a delay and signal processed, the auxiliary power cylinder pressure p ESP of the ESP sensor 36 has a time delay t F with respect to the calculated virtual auxiliary power cylinder pressure p v . When comparing the two values, this time delay t ESP is taken into account for the auxiliary power cylinder pressure p v .

[0023] In the fifth step E, when comparing the detected deviation Δp between the two values, the correlation p F (M M ) is adjusted according to the deviation Δp, and the virtual auxiliary power cylinder pressure p F This is newly recorded for the calculation. This calculates the virtual auxiliary power cylinder pressure p F This can improve accuracy.

[0024] Figure 3 shows the time delay t. v An embodiment of a method for determining the time delay t is shown. For this purpose, in the first determination step M, a test signal is applied between the control unit and the ESP pressure sensor. In the second determination step N, the arrival time of the test signal is measured. From this arrival time, the time delay t is calculated. v This value is obtained. This value can then be updated in the manner shown in Figure 2. Time delay t v The corrected value improves the accuracy of the comparison between the two, resulting in a more precise correlation p F (M M ) can be calculated. [Explanation of Symbols]

[0025] 1. Auxiliary power brake system 4 units, 1st unit 8 units, second unit, ESP brake system 12. Auxiliary power type brake pressure generator 16 Auxiliary power cylinder 20 Auxiliary power cylinder motor 24 Auxiliary power piston 28 Control Units 32 Wheel Brakes 36 ESP pressure sensors A. First step B. Second Step C. Third Step D. Fourth step E. Step 5 p ESP Auxiliary power cylinder pressure of ESP pressure sensor 36 pF Auxiliary power cylinder pressure p F (M M ) Correlation, correlation model R Auxiliary power cylinder control t v Time delay M First decision stage N Second decision stage M M Motor values, torque X location Δp deviation

Claims

1. Auxiliary power cylinder pressure (p) of auxiliary power brake device (1) Ｆ In a method for calculating ), At least one motor value (M) of the auxiliary power cylinder motor (20) Ｍ Step (A) to calculate ) and The motor value (M Ｍ ) and virtual auxiliary power cylinder pressure (p Ｆ Correlation model between (p Ｆ (M Ｍ Using the motor value (M Ｍ ) from the virtual auxiliary power cylinder pressure (p Ｆ Step (B) to calculate ) and Step (C) of calculating the auxiliary power cylinder pressure (p ＥＳＰ ) by the ESP pressure sensor (36) within the ESP brake system (8); The aforementioned virtual auxiliary power cylinder pressure (p Ｆ ) and the auxiliary power cylinder pressure (p) measured by the ESP pressure sensor (36) ＥＳＰ Time delay between (t) ｖ Taking into consideration the virtual auxiliary power cylinder pressure (p Ｆ ) the auxiliary power cylinder pressure (p) of the ESP pressure sensor (36) ＥＳＰ Step (D) to compare with The correlation model (p) is determined according to the calculated deviation (Δp). Ｆ (M Ｍ Step (E) to correct )) and The auxiliary power cylinder pressure (p) of the auxiliary power brake device (1) has Ｆ A method for calculating ).

2. The measured auxiliary power cylinder pressure (p) of the ESP pressure sensor (36) ＥＳＰ The time to reach the specified value is measured, and the virtual auxiliary power cylinder pressure (p) is used to determine the virtual auxiliary power cylinder pressure (p) Ｆ ) and the measured auxiliary power cylinder pressure (p) of the ESP pressure sensor (36) ＥＳＰ The time delay (t) between ) ｖ The method according to claim 1, characterized by adjusting ).

3. The aforementioned time delay (t ｖ The method according to claim 2, characterized in that it calculates the arrival time of a test signal in order to measure ).

4. The aforementioned virtual auxiliary power cylinder pressure (p Ｆ To calculate the motor value (M Ｍ The method according to any one of claims 1 to 3, characterized in that torque is used as ).

5. The aforementioned virtual auxiliary power cylinder pressure (p Ｆ The method according to any one of claims 1 to 3, characterized in that motor current is used as the motor value in order to calculate ).

6. Apparatus for carrying out the method according to any one of claims 1 to 3, It has an auxiliary power cylinder (16), and auxiliary power cylinder pressure can be generated by an auxiliary power cylinder motor (20) via the auxiliary power cylinder (16), It has an ESP pressure sensor (36), and the auxiliary power cylinder pressure (p) is transmitted via the ESP pressure sensor (36). ＥＳＰ The time-delayed pressure of ) is measurable, It has a control unit (28), and the control unit (28) controls the virtual auxiliary power cylinder pressure (p Ｆ ) is the motor value (M Ｍ ) and the virtual auxiliary power cylinder pressure (p Ｆ Correlation model between (p Ｆ (M Ｍ A device that can calculate using ).

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