Method for controlling braking force distribution in a vehicle braking system to reduce or eliminate noise and / or vibration - Patents.com

Abstract

The invention relates to a method (500; 600) for controlling a braking system (1000) of a vehicle (1) to distribute a braking force (F1, F2, F3, F4, F5, F6) to at least one piston (P31, P41, P11, P12, P21, P22) of a disc brake caliper (P3, P4, P1, P2) of the vehicle (1). The method is executed by a brake system control system (100). The method includes the steps of receiving (501) by a control system a request to apply a brake force (X) following a braking action applied to a pedal / button (5, EPB-B) of the brake system, applying (502) the requested brake force (X) to at least one piston, detecting (503) current characteristic frequency (FReq) information of the brake system by at least one sensor operatively associated with the brake system, and comparing (504) the detected current characteristic frequency information with a reference characteristic frequency (FReq1) representative of a critical operating condition of the brake system. If the detected current characteristic frequency information of the brake system is equal to the reference characteristic frequency, applying (505) to at least one piston of a disc brake caliper of the vehicle an additional brake force (X') generated by superimposing a force signal (SIG) having a time-varying amplitude (A) on the requested brake force (X).

Description

[Technical field]

[0001] Technical Field

[0002] The present invention relates to the field of vehicle braking systems operating with brake-by-wire (BBW) technology, and more particularly to a method for controlling the distribution of braking force in a vehicle braking system comprising at least one disc brake associated with a wheel of the vehicle, to reduce or eliminate noise and / or vibrations generated in the system. [Background technology]

[0003] Background technology

[0004] As is known, a brake system primarily serves two purposes: a service brake and a parking brake.

[0005] A braking system of a vehicle, particularly an automobile, operating with brake-by-wire (BBW) technology has a number of disc brakes, each associated with one wheel of the automobile. Each disc brake has a respective electric brake caliper configured to clamp the disc and lock the disc in a service brake or parking brake. The braking system uses an electronic control unit (ECU) and an electromechanical actuator controlled by the electronic control unit that acts on the electric motor of the brake caliper by enabling / disabling the clamping of the caliper.

[0006] In the automotive field, a typical parameter for measuring vehicle comfort is denoted by the acronym NVH (Noise, Vibration, And Harshness). This parameter provides guidance on the perceived noise and vibration characteristics associated with a vehicle. In particular, the braking system of a vehicle is directly responsible for the generation of noise and vibration in a vehicle.

[0007] Currently, in order to reduce the noise and vibration associated with a vehicle's braking system, it is known to carry out tests on prototypes of the braking system during design and development, which makes it possible to optimize the test system before production starts.

[0008] However, solving the problems of reducing noise and vibration in the test braking system requires multiple iterations of improvements, which will require long development times and significant resources.

[0009] In other words, in practice, this step of testing to optimize the braking system is often too costly or excessively time consuming to complete.

[0010] Therefore, there remains a strong felt need to reduce or eliminate the noise and / or vibrations generated in vehicle braking systems, in particular in motor vehicles, and to be able to overcome the limitations and drawbacks of the known methods mentioned above.

[0011] solution

[0012] The object of the present invention is to devise and make available a method for controlling the distribution of braking force in a vehicle braking system consisting of at least one disc brake associated with a wheel of the vehicle, in order to reduce or eliminate noise and / or vibrations generated in the system.

[0013] This need is met by a method for controlling a braking system of a vehicle as set forth in claim 1.

[0014] The control method of the invention comprises an algorithm for implementing an active control of a vehicle's brake system, which is configured to be activated only if current operating frequency information of the brake system is detected, for example by a microphone or an accelerometer, which is equal to a threshold or critical frequency located within a range or band of critical frequencies having a predefined amplitude. For example, this range of critical frequencies comprises all frequencies around a reference critical frequency value or a central band critical frequency value, for example critical frequencies that differ in absolute value from the reference critical frequency by more than 5%, in particular by more than 3%.

[0015] A further object of the invention is a vehicle brake system control system for distributing brake forces as claimed in claim 9.

[0016] Some advantageous embodiments are the subject of the dependent claims. [Brief description of the drawings]

[0017] drawing

[0018] Further characteristics and advantages of the control method according to the invention will become apparent from the description given below of preferred exemplary embodiments thereof, given as non-limiting examples, with reference to the attached drawings, in which:

[0019] [Figure 1] FIG. 1 shows diagrammatically an example of a vehicle brake system architecture employing a system for controlling the distribution of braking force for service braking or parking braking of a vehicle implementing the method according to the invention.

[0020] [Diagram 2] FIG. 2 illustrates in flow chart form an embodiment of a method for controlling brake force distribution in the braking system of FIG.

[0021] [Diagram 3]FIG. 3 shows in a flow chart a further embodiment of a method for controlling braking force distribution in the braking system of FIG.

[0022] [Figure 4] FIG. 4 shows in a flow chart a further embodiment of a method for controlling braking force distribution in the braking system of FIG.

[0023] [Diagram 5] FIG. 5 shows in a flow chart a first embodiment of a method for controlling the brake force distribution in the brake system of FIG. 1 according to the invention.

[0024] [Figure 6] FIG. 6 shows in a flow chart a second embodiment of a method for controlling the brake force distribution in the brake system of FIG. 1 according to the invention.

[0025] Similar or equivalent elements in the above described figures are indicated with the same reference numerals.

[0026] Description of the Preferred Embodiment

[0027] 1, reference numeral 1000 indicates as a whole a braking system of a vehicle 1 comprising a braking system control system 100 according to the present invention for distributing braking forces for the service brakes and / or parking brakes of the vehicle 1. Hereinafter, this braking system control system 100 will also be referred to simply as the control system or the system.

[0028] For example, a braking system 1000 in which the control system 100 can be used is an architecture that uses brake-by-wire (BBW) technology.

[0029] In this specification, "vehicle" means a vehicle or motorcycle, also of a commercial type, having two, three, four or more wheels.

[0030] Furthermore, "brake system" means the totality of all components (mechanical and / or electrical or electronic, as well as brake fluid) that contribute to the application of the vehicle's service brakes or the application of the vehicle's parking brakes.

[0031] Referring to FIG. 1, a vehicle 1 includes a front axle A1 to which a first front wheel FL and a second front wheel FR are connected.

[0032] For example, the first front wheel FL is the left front wheel, and the second front wheel FR is the right front wheel.

[0033] Furthermore, the vehicle 1 includes a rear axle R1 to which a first rear wheel RL and a second rear wheel RR are connected.

[0034] For example, the first rear wheel RL is the left rear wheel and the second rear wheel RR is the right rear wheel.

[0035] The braking system 1000 comprises at least one first actuator module 2 operably connected to the first front axle A1.

[0036] The braking system 1000 further comprises at least one second actuator module 3 operably connected to the rear axle R1.

[0037] Each actuator module 2, 3 consists of one or more actuators for each wheel per axle.

[0038] Each actuator is either electromechanical or electrohydraulic.

[0039] With reference to the embodiment shown in FIG. 1, at least one first actuator module 2 operatively connected to the front axle A1 comprises a first actuator ACT1 and a second actuator ACT2 configured to act on a first brake caliper P1, in particular a two-piston caliper, of a first front wheel FL.

[0040] More specifically, the first brake caliper P1 is composed of a first piston P11 and a second piston P12 which are biased by a first actuator ACT1 and a second actuator ACT2, respectively.

[0041] Furthermore, the at least one first actuator module 2 comprises a third actuator ACT3 and a fourth actuator ACT4 configured to act on a second brake caliper P2 of the second front wheel FR, in particular a two-piston caliper.

[0042] More specifically, the first brake caliper P2 is composed of a first piston P21 and a second piston P22 which are respectively biased by a third actuator ACT3 and a fourth actuator ACT4.

[0043] Referring again to the embodiment shown in Figure 1, the at least one second actuator module 3 operatively connected to the rear axle R1 comprises a fifth actuator ACT5 configured to act on a third brake caliper P3 of the first rear wheel RL, which is in particular a single-piston caliper.

[0044] More specifically, this third brake caliper P3 is composed of a respective first piston P31 actuated by a fifth actuator ACT5.

[0045] Furthermore, the at least one second actuator module 3 includes a sixth actuator ACT6 configured to act on a fourth brake caliper P4 of the second rear wheel RR. In particular, this fourth brake caliper is a single-piston caliper.

[0046] More specifically, this fourth brake caliper P4 is composed of a respective first piston P41 biased by a sixth actuator ACT6.

[0047] It is worth noting that the architecture of the brake system 1000 described above, consisting of a caliper with two pistons acting on the wheels of the front axle A1 and a single-piston caliper acting on the wheels of the rear axle R1, is an example. Indeed, for the purposes of the present invention, several variants and combinations of variants can be provided, such as, for example, calipers with more than two pistons on both the wheels of the front axle and on the wheels of the rear axle, calipers with two pistons also on the wheels of the rear axle, single-piston calipers on both the wheels of the front axle and on the wheels of the rear axle, etc. It is further worth noting that, for the purposes of the present invention, the aforementioned brake calipers P1, P2, P3, P4 may be calipers of the "dry" or "wet" type.

[0048] Each actuator ACT1, ACT2, ACT3, ACT4, ACT5, ACT6 is configured to execute a brake command based on control received from a respective electronic actuator control module or electronic brake control unit or BCU. Each actuator control module may be, for example, a hardware module or a software logic module within the braking system (standalone or integrated in the actuator itself) or a hardware module of the vehicle 1.

[0049] With reference to the example of FIG. 1, electronic brake control units BCU1, BCU2, BCU3 contribute to forming a control system 100 of a brake system 1000 of a vehicle 1.

[0050] In particular, each of the aforementioned electronic brake control units BCU1, BCU2, BCU3 comprises, for example, a microcontroller or microprocessor and is configured to generate electrical signals for the actuation of electrically actuated brake calipers P1, P3, P4 of the system 1000.

[0051] In particular, the control system 100 of the braking system 1000 comprises a first brake control unit BCU1 operatively connected to the second actuator module 3 .

[0052] This first brake control unit BCU1 or main control unit is configured to directly control the second actuator module 3 to apply service braking to the wheels of the rear axle R1 of the vehicle 1 in response to a braking action applied to the pedal 5 of the brake system 1000.

[0053] This first brake control unit BCU1, via secondary brake control units BCU2, BCU3, is configured to control the first actuator module 2 and perform service braking on the wheels of the front axle A1 of the vehicle 1 in response to a braking action applied on the pedal 5 of the brake system 1000.

[0054] In particular, the first brake control unit BCU1 is configured to calculate target brake torque values ​​to be applied to both the rear axle wheels R1 and the front axle wheels A1 of the vehicle 1 based on the brake signals S1, S2 generated as a result of an actuation applied to the pedal 5 of the system 1000. This first brake control unit BCU1 is for example called a "master control unit".

[0055] The target brake torque values ​​are provided to the secondary brake control units BCU2, BCU3 via a bidirectional data communication line or bus CAN1, for example of the serial type, connecting the first brake control unit BCU1 and the secondary brake control units BCU2, BCU3.

[0056] Referring to the example of FIG. 1, the secondary brake control units BCU2, BCU3 are composed of a second brake control unit BCU2 and a third brake control unit BCU3, each of which is connected to the first brake control unit BCU1 via a data communication line CAN1.

[0057] In an embodiment, the second brake control unit BCU2 is configured to receive the target brake torque values ​​generated by the first brake control unit BCU1 and apply them to the wheels of the front axle A1. In this operational configuration, the second brake control unit BCU2 operates as a "slave control unit".

[0058] In particular, referring to the example of FIG. 1, the second brake control unit BCU2 is configured to control both the third actuator ACT3 of the second front wheel FR and the first actuator of the first front wheel FL.

[0059] In a different embodiment, the second brake control unit BCU2 is configured to generate target brake torque values ​​in the background and independently of the first brake control unit BCU1 to apply to each wheel of the front axle A1. In particular, the target brake torque values ​​are generated based on a further brake signal S3 that is generated as a result of an actuation on the pedal 5 of the system 1000. In this operating configuration, the second brake control unit BCU2 operates as a "quasi-master control unit" making it possible to manage the braking of the wheels of the front axle A1 even in the event of a failure of the first brake control unit BCU1.

[0060] In an embodiment, the third brake control unit BCU3 is configured to receive the target brake torque values ​​generated by the first brake control unit BCU1 and to apply them to each wheel of the front axle A1. In this operational configuration, this third brake control unit BCU3 acts as a "slave control unit". Unlike a "quasi-master control unit", the third brake control unit BCU3 is not tasked with generating the target brake torque values.

[0061] In particular, the third brake control unit BCU3 is configured to control both the second actuator ACT2 of the first front wheel FL and the fourth actuator of the second front wheel FR.

[0062] Based on the control of the actuators ACT1, ACT2, ACT3, ACT4 achieved via the second brake control unit BCU2 and the third brake control unit BCU3, the system 100 of the present invention ensures balanced braking of both wheels of the front axle A1 of the vehicle 1, even if one of the control units fails.

[0063] In one embodiment, the brake electronic control units of the first brake control unit BCU1, the second brake control unit BCU2 and the third brake control unit BCU3 are powered via the DC voltage of the battery 30 of the vehicle 1 via their respective power manager blocks 31 of the brake system 1000.

[0064] Further, the brake system 1000 operatively associates respective wheel speed sensors WS1, WS2, WS3, WS4 with one of the wheels of the vehicle 1, the rear wheels first RL and second RR, respectively, and the front wheels first FL and second FR, and is configured to detect the speed of each wheel, which is transmitted to the respective brake control unit.

[0065] In particular, the first WS1 and second WS2 speed sensors are connected to a first brake control unit BCU1, while the third WS3 and fourth WS4 speed sensors are connected to a second brake control unit BCU2.

[0066] Referring to the example of FIG. 1, at least one first actuator module 2 of the brake system 1000 includes first EP1 and second EP2 parking actuators configured to act on first P1 and second P2 brake calipers, respectively, of the front axle A1 when the parking brake is activated.

[0067] Referring again to the embodiment shown in FIG. 1, the at least one second actuator module 3 comprises third EP3 and fourth EP4 parking actuators configured to act on the third P3 and fourth P4 brake calipers, respectively, of the rear axle R1 when the parking brake is activated.

[0068] The first EP1 and second EP2 parking actuators are controlled by a third brake control unit BCU3. The third EP3 and fourth EP4 parking actuators are controlled by a first brake control unit BCU1.

[0069] In particular, a parking command is activated by a parking control unit 20 of the vehicle 1 following a pressure applied by a user on the parking button EPB-B. This parking control unit 20 is configured to transmit said parking command to the first BCU1, second BCU2 and third BCU3 brake control units of the system via a further bidirectional data communication line or bus CAN2, for example of serial type, connecting the parking control unit 20 to each of the brake control units BCU1, BCU2, BCU3.

[0070] 2-4, in the following there will be explained in more detail the operating steps of a method 200, 300, 400 for controlling the distribution of braking forces F3, F4, F5, F6 to at least one first piston P11, P21 and at least one second piston P12, P22 of a disc brake caliper P1, P2 of a vehicle 1 in a braking system 1000 of the vehicle 1. The control method is implemented via the control system 100 described above.

[0071] In particular, the control method comprises a first algorithm implementing a passive control of the braking system 1000 of the vehicle 1. This first algorithm is adapted to be activated whenever the braking system is in a predefined critical state.

[0072] By way of example, in the following reference will be made to first pistons P11, P21 and second pistons P12, P22 of disc brake calipers P1, P2 of the front axle A1 of the vehicle 1.

[0073] In a typical embodiment, each of the aforementioned brake control units, the first BCU1, the second BCU2 and the third BCU3 of the system 100, is configured to execute the code of an application program implementing the methods 200, 300, 400.

[0074] For example, with reference to the example of FIG. 1, it will be assumed below that the control methods 200, 300, 400 are implemented by the second BCU2 and / or third BCU3 brake control units of the system 100.

[0075] In certain embodiments, the processor of the controlled brake unit is configured to load and execute application program code implementing the methods 200, 300, 400 into a respective memory block.

[0076] The control methods 200, 300, 400 of FIG. 2-4 begin with a start "STR" symbol step and end with an end "ED" symbol step.

[0077] In its most general embodiment, the control method 200, 300, 400 of the braking system 1000 comprises a step 201 of receiving, by the control system 100, a request to apply a braking force X following a braking action applied, for example by a user, on the pedal 5 (or button EPB-B) of the braking system 1000.

[0078] The methods 200, 300, 400 further comprise a step 202 of receiving, by the control system 100, a first plurality of parameters V, Temp, F, S, DPTemP associated with the brake system 1000, each representative of a current operating state of the brake system.

[0079] This first plurality of parameters preferably consists of, but is not limited to, information regarding the current speed V of the vehicle 1, the current temperature TemP of the external environment, the current working force / pressure F, the current slope S of the wheel running surface, the current temperature of the disc pads or the current temperature DPTemP of the disc itself.

[0080] This first plurality of parameters V, TemP, F, S, DPTemP can be obtained from the control system 100 through suitable sensors or "estimation" devices equipped in the BBW brake system 1000 of the vehicle 1, such as the aforementioned speed sensors WS1, WS2, WS3, WS4, or sensors (HW) or estimators (SW) equipped in the brake system or vehicle, sensors for ambient temperature, road gradient, brake system pressure, etc.

[0081] Further, a step 203 is provided in which the control system 100 compares each received parameter V, TemP, F, S, DPTemP of the first plurality of parameters with each reference parameter Vc, TemPc, Fc, Sc, DPTemPc of a second plurality of parameters representative of critical operating states of the brake system 1000.

[0082] This second plurality of parameters preferably consists of, but is not limited to, information on the critical speed Vc of the vehicle 1, the critical temperature TemPc of the external environment, the critical working force / pressure Fc, the critical gradient Sc of the wheel running surface, the critical temperature DPTemPc of the disc pads, or the critical temperature of the disc itself. It is worth noting that each critical benchmark parameter Vc, TemPc, Fc, Sc, DPTemPc of the braking system 1000 can assume a single critical parameter value or, preferably, take multiple values ​​from a range of values ​​representative of the same critical parameter, for example different values ​​of the "critical" pressure or speed, or even different combinations of parameters with each other. In fact, a particular braking system noise or disturbance frequency 1000 is associated with multiple estimated and measured critical parameter values ​​for a particular operating condition. For example, a noise frequency of 2 kHz is characterized for a speed of 5-15 km / h, a pressure of 10-20 bAR, and a temperature of -5 ° C - 0 ° C. Other noise having a different frequency is associated with a respective plurality of estimated and measured critical parameter values ​​that are specific to this frequency and differ from the aforementioned values ​​associated with the 2 kHz noise frequency.

[0083] This second plurality of parameters Vc, TemPc, Fc, Sc, DPTemPc (either a single value or a set of values) is stored, for example, in a CAN database of the vehicle 1.

[0084] If at least one of the parameters V, TemP, F, S, DPTemP of the first plurality of parameters is equal to the respective reference parameters Vc, TemPc, Fc, Sc, DPTemPc of the second plurality of parameters, the methods 200, 300, 400 comprise the following steps.

[0085] Step 204: applying a first braking force Y to first pistons P11, P21 of disc brake calipers P1, P2 of the vehicle 1.

[0086] Step 205 applies a second braking force Z to the second pistons P12, P22 of the disc brake calipers P1, P2 of the vehicle 1.

[0087] In particular, the sum of the above-mentioned first braking force Y and second braking force Z is equal to the required braking force X, and the ratio of the first braking force Y to the second braking force Z is different from one.

[0088] If each parameter V, TemP, F, S, DPTemP of the first plurality of parameters differs from each reference parameter Vc, TemPc, Fc, Sc, DPTemPc of the second plurality of parameters, i.e. if the braking system is outside the critical operating range, the method 200, 300, 400 includes a step 206 of applying a third brake force X / 2, equal to half the required brake force X, to both the first pistons P11, P21 and the second pistons P12, P22 of the disc brake calipers P1, P2 of the vehicle 1.

[0089] In an alternative embodiment, when each parameter V, Temp, F, S, DPTemP of the first plurality of parameters is different from each reference parameter Vc, Temp, Fc, Sc, DPTemP of the second plurality of parameters, i.e., when the braking system is out of critical condition, the method 200, 300, 400 further comprises: applying a first further braking force and a second further braking force to first pistons P11, P21 and second pistons P12, P22, respectively, of disc brake calipers P1, P2 of vehicle 1, where a ratio (not "1") between said first further braking force and said second further braking force is predetermined, and a sum of said first further braking force and said second further braking force is equal to a required braking force X.

[0090] It is worth noting that the relationship between the first braking force Y and the second braking force Z is characterized in order to avoid instabilities (noise) during the development of the calipers P1, P2, and is not only a function of the instability of the calipers, but also as a function of the level of clamping force, temperature and vehicle speed at which this instability is triggered.

[0091] In an embodiment, the ratio between the first braking force Y and the second braking force Z is selected to be greater than one.

[0092] During experimental tests carried out on a test vehicle, the applicant observed that the calipers P1, P2 exhibit instabilities at 5 kHz, 0° C., a speed V<15 km / h and a force value F comprised between 5-10 kN. Furthermore, the applicant experimentally verified that under these operating conditions, the aforementioned instabilities disappear when the first braking force Y and the second braking force Z are calculated according to the following formulas: First brake force Y = 0.8 x required brake force X Second brake force Z = 0.2 x required brake force X

[0093] 3, in a further embodiment, when at least one of the parameters V, Temp, F, S, DPTemP of the first plurality of parameters is equal to a respective reference parameter Vc, Temp, Fc, Sc, DPTemPc of the second plurality of parameters, the method 300 comprises, after the aforementioned steps of applying 204, 205, a step 301 of detection by the control system 100, by means of at least one sensor operatively associated with the system, of information of a current characteristic frequency FReq of the braking system 1000, said characteristic frequency FReq being representative of a current noise and / or vibration associated with the braking system 1000.

[0094] In one example embodiment, at least one sensor operatively associated with the braking system 1000 has the following configuration:

[0095] at least one microphone operatively associated with the braking system;

[0096] A plurality of acceleration sensors each associated with a disc brake caliper P1, P2 of the vehicle 1.

[0097] In one embodiment, the aforementioned microphone associated with the braking system may in the most general case be a microphone already installed in the automobile (either inside or outside the passenger compartment), such as, for example, an internal hands-free microphone.

[0098] The method 300 further provides a step 302 of comparing, by the control system 100 , the detected current characteristic frequency FReq with a reference characteristic or critical frequency FReq 1 representative of a critical operating condition of the brake system 1000 .

[0099] Preferably, said critical frequency FReq1 consists of a range or band of critical frequencies with a certain amplitude. For example, this critical frequency range consists of all frequencies around a reference critical frequency value or a central band critical frequency value, for example frequencies that differ from the reference critical frequency by more than 5%, in particular by more than 3% in absolute value. Therefore, in the following, the term characteristic reference frequency or critical frequency FReq1 is used to indicate both the value of said reference critical frequency and all values ​​of frequencies within said frequency band that differ from the reference critical frequency by a tolerance of more than 5%, in particular by more than 3%.

[0100] The critical frequency FReq1 is measured at the stage of developing the braking system and the critical frequency reference values ​​relevant for noise and vibration detection are characterized at the stage of product development before technology approval or the start of production on a roller stand bench or prototype vehicle.

[0101] If the detected current characteristic frequency information FReq of the brake system 1000 is equal to the reference characteristic frequency FReq1, i.e., if the current characteristic frequency FReq is a frequency within the aforementioned critical frequency band defined around the value of the reference characteristic frequency, the method 300 further comprises the following steps:

[0102] Step 303 applies a fourth braking force Y1 generated by superimposing a force signal SIG, SIG1 having a time-varying amplitude A on the first braking force Y to a first piston P11, P21 of a disc brake caliper P1, P2 of the vehicle 1.

[0103] Step 304 applies a fifth braking force Z1 generated by superimposing this force signal SIG, SIG1 having a time-varying amplitude A on the second braking force Z to at least one second piston P12, P22 of the disc brake caliper P1, P2 of the vehicle 1.

[0104] In particular, the sum of the fourth braking force Y1 and the fifth braking force Z1 is equal to the required braking force X.

[0105] 3, in a further embodiment, when at least one of the parameters V, Temp, F, S, DPTemP of the first plurality of parameters differs from the respective reference parameters Vc, Temp, Fc, Sc, DPTemPc of the second plurality of parameters, the method 300 comprises, after the aforementioned applying step 206, a step 301 of detecting, by the control system 100, by means of at least one sensor operatively associated with the system, current characteristic frequency information FReq of the braking system 1000. This characteristic frequency FReq is representative of the current noise and / or vibration associated with the braking system 1000.

[0106] Furthermore, the method 300 provides a step 302 of comparing, by the control system 100 , this detected current characteristic frequency FReq with a reference characteristic frequency FReq 1 representative of a critical operating condition of the brake system 1000 .

[0107] If the detected current characteristic frequency information FReq of the brake system 1000 is equal to the reference characteristic frequency FReq1, i.e., if the current characteristic frequency FReq is within a critical frequency band defined around the value of the reference characteristic frequency, the method 300 further comprises the following steps.

[0108] Step 204: applying a first braking force Y to first pistons P11, P21 of disc brake calipers P1, P2 of the vehicle 1.

[0109] Step 205 of applying a second braking force Z to at least one second piston P12, P22 of the disc brake caliper P1, P2 of the vehicle 1.

[0110] In particular, the sum of the aforementioned first braking force Y and second braking force Z is equal to the required braking force X, and the ratio of the first braking force Y to the second braking force Z is different from one.

[0111] As described above, the method 300 further includes step 301 of detecting, by the control system 100, by at least one sensor operatively associated with the system, further current characteristic frequency information FReq' of the brake system 1000, and step 302 of comparing, by the control system 100, the detected further current characteristic frequency information FReq' with a reference characteristic frequency FReq1 of the brake system.

[0112] If this further detected current characteristic frequency FReq' of the braking system is equal to the reference characteristic frequency FReq1, the method 300 further includes the following steps.

[0113] Step 303 of applying a fourth braking force Y1 to at least one first piston P11, P21 of the screW brake caliper P1, P2.

[0114] Step 304 of applying a fifth braking force Z1 to at least one second piston P12, P22 of the disc brake caliper P1, P2 of the vehicle 1.

[0115] In one embodiment, the aforementioned force signals SIG, SIG1 having a time-varying amplitude A consist of signals assuming amplitude values ​​that are either greater or less than an average value.

[0116] In certain embodiments, the force signal SIG, SIG1 having a time-varying amplitude A is selected from the group consisting of a sine signal, a ramp signal, a triangle wave signal, a square wave signal, and a signal that varies randomly around a mean value.

[0117] In a further particular embodiment, the force signals SIG, SIG1 having a time-varying amplitude A consist of a first force signal SIG and a second force signal SIG1 which are of opposite phase to each other, the first force signal SIG being superimposable on the first braking force Y to generate a fourth braking force Y1 and the second force signal SIG1 being superimposable on the second braking force Z to generate a fifth braking force Z1.

[0118] In the embodiment, the frequency at which the first force signal SIG and the second force signal SIG1 can be superimposed is at least within the range of 1-200 Hz.

[0119] Referring to FIG. 4, in a further embodiment, when each parameter V, TemP, F, S, DPTemP of the first plurality of parameters is different from each reference parameter Vc, TemPc, Fc, Sc, DPTemPc of the second plurality of parameters, the method 400 comprises, after the aforementioned step of applying 206, the following steps:

[0120] Step 301 of detecting, by the control system 100, a further current characteristic frequency FReq of the braking system 1000 by means of at least one sensor operatively associated with the system.

[0121] The control system 100 compares this detected current characteristic frequency FReq with a reference characteristic frequency FReq1 representative of a critical operating condition of the brake system 1000, step 302.

[0122] If the detected current characteristic frequency FReq of the braking system 1000 is equal to the reference characteristic frequency FReq1, the method 400 comprises a step 401 of randomly selecting a first distribution method 402 or a second distribution method 403 of the braking forces F3, F4, F5, F6 on the first pistons P11, P21 and the second pistons P12, P22 of the calipers P1, P2 of the vehicle disc brake 1.

[0123] More specifically, the first distribution method 402 of the braking forces F3, F4, F5, F6 comprises the following steps:

[0124] Step 204: applying a first braking force Y to first pistons P11, P21 of disc brake calipers P1, P2 of the vehicle 1.

[0125] Step 205: applying a second braking force Z to the second pistons P12, P22 of the disc brake calipers P1, P2.

[0126] Here, the sum of the first braking force Y and the second braking force Z is equal to a required braking force X, and the ratio of the first braking force Y to the second braking force Z is different from 1.

[0127] Furthermore, the method 400 provides the following steps.

[0128] Step 301' of detecting, by the control system 100, by means of at least one sensor operatively associated with the system, further current characteristic frequency information FReq' of the braking system 1000.

[0129] Step 302' of comparing said further detected current characteristic frequency information FReq' with a reference characteristic frequency FReq1 of the braking system by the control system 100.

[0130] If this further detected current characteristic frequency information FReq' of the braking system 1000 is equal to the reference characteristic frequency FReq1, the method 400 further includes the following steps.

[0131] Step 303: applying a fourth braking force Y1 generated by superimposing a force signal SIG having a time-varying amplitude A on the first braking force Y to first pistons P11, P21 of disc brake calipers P1, P2 of the vehicle.

[0132] Step 304 applies a fifth braking force Z1 to second pistons P12, P22 of the vehicle disc brake calipers P1, P2, which is generated by superimposing said force signal SIG1 having a time-varying amplitude A on a second braking force Z.

[0133] Here, the sum of the fourth braking force Y1 and the fifth braking force Z1 is equal to the required braking force X.

[0134] Referring again to FIG. 4, in a further embodiment, the aforementioned second distribution method 403 for the braking forces F3, F4, F5, F6 includes the following steps:

[0135] making available a first braking force Y and a second braking force Z, the sum of the first braking force Y and the second braking force Z being equal to a requested braking force X and the ratio of the first braking force Y to the second braking force Z being different from 1.

[0136] Step 303 applies a fourth braking force Y1 generated by superimposing a force signal SIG having a time-varying amplitude A on the first braking force Y to at least one first piston P11, P21 of a disc brake caliper P1, P2 of the vehicle.

[0137] Step 304 applies a fifth braking force Z1 generated by superimposing the aforementioned force signal SIG1 having a time-varying amplitude A on the second braking force Z to at least one second piston P12, P22 of the disc brake caliper P1, P2 of the vehicle 1.

[0138] In particular, the sum of the fourth braking force Y1 and the fifth braking force Z1 is equal to the required braking force X.

[0139] The method 400 further comprises a step 301′ of detecting, by the control system 100, by at least one sensor operatively associated with the system, further current characteristic frequency information FReq′ of the braking system 1000;

[0140] The control system 100 further includes a step 302' of comparing the detected current characteristic frequency information FReq' with a reference characteristic frequency FReq1 of the brake system.

[0141] If this further detected current wave number information FReq' is equal to the reference characteristic frequency FReq1, the method 400 further includes the following steps.

[0142] Step 204: applying a first braking force Y to first pistons P11, P21 of disc brake calipers P1, P2 of the vehicle 1.

[0143] Step 205: applying a second braking force Z to the second pistons P12, P22 of the calipers P1, P2.

[0144] With reference to Figures 5-6, the following describes in more detail the operating steps of a method 500, 600 for controlling the distribution of braking forces F1, F2, F3, F4, F5, F6 on at least one piston P31, P41, P11, P12, P21, P22 of a disc brake caliper P3, P4, P1, P2 of a vehicle 1 in a braking system 1000 of the vehicle 1 of the present invention.

[0145] The control method is implemented through the control system 100 described above.

[0146] The inventive control method 500, 600 comprises a second algorithm for implementing active control of the braking system 1000 of the vehicle 1. This second algorithm is configured to be activated only if current FReq operating frequency information of the braking system is detected, for example by a microphone or an accelerometer, which is equal to a preset reference or critical frequency FReq1.

[0147] It is worth noting that this control method 500 of the invention is applicable to single piston calipers, i.e. distribution of braking forces on the first pistons P31, P41 of the third caliper P3 and the fourth caliper P4 of the rear axle R1 of the vehicle 1. In another embodiment, the method 600 is further applicable to calipers with more than two pistons, for example the first pistons P11, P21 and the second pistons P12, P22 of the disc brake calipers P1, P2 of the front axle A1 of the vehicle 1.

[0148] In a general embodiment, each of the aforementioned first BCU1, second BCU2 and third BCU3 brake control units of the system 100 is arranged to execute the code of an application program implementing the inventive methods 500, 600. In other words, in the following, it is assumed that the control methods 500, 600 are implemented by any of the brake control units of the system 100.

[0149] In a particular embodiment, the processor of the controlled brake unit is configured to load into a respective memory block and execute the code of an application program implementing the methods 500, 600 of the present invention.

[0150] The control methods 500, 600 of FIG. 5-6 begin with a start "STR" symbol step and end with an end "ED" symbol step.

[0151] The control method 500 includes a step 501 of receiving by the control system 100 a request to apply a braking force X following a braking action applied to the pedal 5 (or EPB-B button) of the braking system 1000 .

[0152] Furthermore, in the case of a single piston caliper P3 or P4, the method 500 includes applying 502 a required braking force X to said piston P31, P41.

[0153] The method 500 further includes a step 503′ of further detecting, by the control system 100, by at least one sensor operatively associated with the brake system, current characteristic frequency information FReq′ of the brake system 1000, the characteristic frequency FReq being representative of current noise and / or vibration associated with the brake system 1000.

[0154] In one embodiment, at least one sensor operatively associated with the braking system 1000 includes the following features.

[0155] At least one microphone operatively associated with the braking system.

[0156] A plurality of acceleration sensors each associated with a disc brake caliper P1, P2 of the vehicle 1.

[0157] In one embodiment, the aforementioned microphone associated with the braking system can in the most general case be a microphone already installed in the automobile (either inside or outside the passenger compartment), such as, for example, an internal hands-free microphone.

[0158] Further included is a step 504 in which the control system 100 compares the detected current characteristic frequency FReq with a reference characteristic frequency FReq1 representative of a critical operating condition of the brake system 1000.

[0159] If this detected current characteristic frequency information FReq of the braking system 1000 is equal to the reference characteristic frequency FReq1, the method 500 includes a step 505 of applying to at least one piston P31, P41 of the calipers P3, P4 of the disc brakes of the vehicle 1 an additional braking force X' generated by superimposing a force signal SIG having a time-varying amplitude A on the requested braking force X.

[0160] In this case, for example, the time-varying amplitude A of the force signal SIG is 20% lower than the average value.

[0161] Furthermore, the variable portion of the force is provided so as not to bias the overall deceleration of the vehicle 1 in any perceptible way, and is compensated in anti-phase between the two axles A1, R1 of the system 1000, keeping the total braking torque, and therefore the deceleration, constant.

[0162] Furthermore, the frequency of the superimposable actuation force signal SIG is at least within the range of 1-200 Hz.

[0163] With reference to FIG. 6, in an embodiment of a method 600 for controlling the distribution of braking forces F3, F4, F5, F6 on the first piston P11, P21 and the second piston P12, P22 of the disc brake calipers P1, P2 of a vehicle 1, the applying step 502 described with reference to FIG. 5 comprises a step 601 of applying a sixth braking force X6 (=X / 2), which is equal to half the requested braking force X, to both the first piston P11, P21 and the second piston P12, P22 of the disc brake calipers P1, P2.

[0164] 5 comprises a step 602 of applying to the first piston P11, P21 and the second piston P12, P22 of the vehicle disc brake calipers P1, P2, respectively, a seventh braking force X1 and a seventh further braking force X2 generated by superimposing the force signal SIG, SIG1 having a time-varying amplitude A on the sixth braking force X6. In particular, the sum of the seventh braking force X1 and the seventh further braking force X2 is equal to the requested braking force X.

[0165] In one embodiment, the force signals SIG, SIG1 having a time-varying amplitude A consist of a first force signal SIG and a second force signal SIG1 in phase opposition to each other. The first force signal SIG is superimposable with a sixth braking force X6 applied to the first pistons P11, P21 to generate a seventh braking force X1.

[0166] The second force signal SIG1 is superimposable with a sixth braking force X6 applied to the second pistons P12, P22 to generate said seventh further braking force X2.

[0167] In an embodiment, the force signals SIG, SIG1 having a time-varying amplitude A consist of signals assuming amplitude values ​​that are either greater or less than an average value.

[0168] In certain embodiments, the force signal SIG, SIG1 having a time-varying amplitude A is selected from the group consisting of a sine signal, a ramp signal, a triangle wave signal, a square wave signal, and a signal that varies randomly around a mean value.

[0169] As demonstrated above, the method 500, 600 for controlling braking force distribution in a braking system 1000 of a vehicle 1 has many advantages and achieves its intended objectives.

[0170] Indeed, the control method of the present invention makes it possible to reduce or eliminate noise and / or vibration generated in a vehicle, particularly an automobile, braking system, while shortening the development time and costs of the system design.

[0171] In particular, it eliminates the need to solve noise and vibration problems through lengthy mechanical design and subsequent testing.

[0172] In fact, by application of the second algorithm described above, it is possible to activate the actuation correction when at least one of the current V, Temp, F, S, DPTemP parameters of the system falls within a critical condition, or to activate the actuation correction control when one of the critical frequencies FReq1 of the braking system is detected by a microphone or an accelerometer, respectively, thereby making it possible to automatically reduce or eliminate the noise and / or vibrations generated in the braking system of the vehicle.

[0173] To meet fortuitous and specific needs, those skilled in the art may make some modifications and adaptations to the above-described method embodiments, and may replace elements with other functionally equivalent ones without departing from the scope of the following claims.

[0174] 1000: Brake system 100: Brake system control system A1: Front axle FL: 1st front wheel FR: 2nd front wheel R1: Particle rear axle RL: 1st rear wheel RR: 2nd rear wheel 2: First actuator module 3: Second actuator module ACT1: First actuator ACT2 Second actuator P1: First brake caliper ACT3: Third actuator ACT4: 4th actuator P2: Second brake caliper ACT5: 5th actuator P3: 3rd brake caliper ACT6: 6th actuator P4: 4th brake caliper BCU1: First brake control unit BCU2: Second brake control unit BCU3: Brake control unit 3 5: Pedal S1, S2: Brake signal S3: Further brake signal CAN1: Data communication line or bus CAN2: Data communication line or bus 20: Parking control unit 30: Battery 31: System power management block WS1: First speed sensor WS: Second speed sensor WS3: 3rd speed sensor WS4: 4th speed sensor EP1: 1st parking actuator EP2: Second parking actuator EP3: 3rd parking actuator EP4: 4th parking actuator EPB-B: Parking button F1, F2, F3, F4, F5, F6: Braking force P11, P21, P13, P14: First piston P12, P22: Second piston V, Temp, F, S, DPTemP: First multiple parameters Vc, TemPc, Fc, Sc, DPTemPc: Second multiple parameters X: Required brake force Y: First brake force Z: Second brake force X / 2: 3rd brake force FReq: Current characteristic frequency information FReq1: Reference characteristic frequency Y1: 4th brake force Z1: 5th brake force SIG: First power signal SIG1: Second force signal FReq': Further current characteristic frequency information X': More braking force X6: 6th brake force X1: 7th brake force X2: Additional 7th braking force 200, 300, 400, 500, 600: Brake force distribution control method 201, 501: Step of receiving a brake force application request 202: Receiving a first plurality of parameters Steps to compare 203, 302, 302', 504: 204, 205, 206, 303, 304, 502, 505, 601, 602: Steps to apply 301, 301', 503: Steps for detecting current characteristic frequency information. 401: Random selection step 402, 403: First and second brake force distribution methods

Claims

1. 1. A method (500; 600) for controlling a braking system (1000) of a vehicle (1) to distribute a braking force (F1, F2, F3, F4, F5, F6) to at least one piston (P31, P41, P11, P12, P21, P22) of a caliper (P3, P4, P1, P2) of a disc brake of the vehicle (1), comprising: The method is performed by a control system (100) of a brake system (1000) for distributing braking force, The method comprises: receiving (501) by said control system (100) a request to apply a braking force (X) following a braking action applied to a pedal / button (5, EPB-B) of said braking system (1000); applying (502) the requested braking force (X) to the at least one piston (P31, P41, P11, P12, P21, P22); a step (503) of detecting, by the control system (100) using at least one sensor operatively associated with the control system (100), information on a current characteristic frequency (FReq) of the brake system (1000), the characteristic frequency (FReq) being representative of current noise and / or vibration associated with the brake system (1000); a step (504) of comparing the detected characteristic frequency (FReq) by the control system (100) with a reference characteristic frequency (FReq1) representative of a critical operating state of the braking system (1000); A method (500; 600) for controlling a brake system (1000) of a vehicle (1), comprising a step (505) of applying an additional brake force (X') to the at least one piston (P31, P41, P11, P12, P21, P22) of the caliper (P3, P4, P1, P2) of the disc brake of the vehicle (1) when the detected characteristic frequency (FReq) of the brake system (1000) is equal to the reference characteristic frequency (FReq1), the additional brake force (X') being generated by superimposing a force signal (SIG) having a time-varying amplitude (A) on the requested brake force (X).

2. A method (600) for distributing braking forces (F3, F4, F5, F6) to first pistons (P11, P21) and second pistons (P12, P22) of the caliper (P1, P2) of the disc brake of the vehicle (1), comprising: the step (502) includes a step (601) of applying a first braking force (X6) equal to half of the requested braking force (X) to both the first piston (P11, P21) and the second piston (P12, P22) of the caliper (P1, P2) of the disc brake of the vehicle (1); the step (505) includes a step (602) of applying a second brake force (X1) and a further second brake force (X2) to the first piston (P11, P21) and the second piston (P12, P22) of the caliper (P1, P2) of the disc brake of the vehicle (1), respectively, the second brake force (X1) and the further second brake force (X2) being generated by superimposing the force signal (SIG, SIG1) having a time-varying amplitude (A) on the first brake force (X6); 2. The method (600) for controlling a braking system (1000) of a vehicle (1) according to claim 1, wherein the sum of the second braking force (X1) and the further second braking force (X2) is equal to the requested braking force (X).

3. The at least one sensor operatively associated with the braking system (1000): at least one microphone operatively associated with the braking system; or 3. A method (500; 600) for controlling a braking system (1000) of a vehicle (1) according to claim 1 or 2, comprising a plurality of acceleration sensors respectively associated with the calipers (P1, P2) of the disc brakes of the vehicle (1).

4. 3. A method (500; 600) for controlling a braking system (1000) of a vehicle (1) according to claim 1 or 2, characterized in that the force signals (SIG, SIG1) with the time-varying amplitude (A) comprise signals with values ​​of amplitude (A) higher or lower than an average value.

5. 3. The method (500; 600) for controlling a braking system (1000) of a vehicle (1) according to claim 1 or 2, wherein the force signal (SIG, SIG1) having the time-varying amplitude (A) is selected from the group consisting of a sine wave signal, a ramp signal, a triangular wave signal, a square wave signal, a signal that varies randomly about a mean value.

6. the force signals (SIG, SIG1) having the time-varying amplitude (A) include a first force signal (SIG) and a second force signal (SIG1) that are out of phase with each other; the first force signal (SIG) can be superimposed on the first braking force (X / 2) applied to the first piston (P11, P21) to generate the second braking force; 5. A method (600) for controlling a braking system (1000) of a vehicle (1) as described in claim 4, wherein the second force signal (SIG1) can be superimposed on the first braking force (X / 2) applied to the second piston (P12, P22) to generate the additional second braking force.

7. the reference characteristic frequency (FReq1) representative of the critical operating state of the brake system (1000) includes a critical frequency band having a predetermined amplitude; 3. A method (500; 600) for controlling a brake system (1000) of a vehicle (1) as described in claim 1 or 2, wherein the critical frequency band includes both a reference characteristic frequency value and frequency values ​​in the vicinity of the reference characteristic frequency value.

8. 8. A method (500; 600) for controlling a brake system (1000) of a vehicle (1) as claimed in claim 7, wherein the critical frequency band has frequency values ​​that differ in absolute value from the reference characteristic frequency value by more than 5%, in particular by more than 3%.

9. A system (100) for controlling a braking system (1000) of a vehicle (1), comprising: The system comprises: Distributing braking forces (F1, F2, F3, F4, F5, F6) to at least one piston (P31, P41, P11, P12, P21, P22) of a brake caliper (P3, P4, P1, P2); at least one electronic brake control unit (BCU1, BCU2, BCU3) configured to generate electrical signals for operating said brake calipers (P1, P2, P3, P4) of the system (1000); A system (100) for controlling a braking system (1000) of a vehicle (1), wherein the at least one electronic brake control unit (BCU1, BCU2, BCU3) is configured to perform the steps of the method according to claim 1.

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