Patent Publication Number: US-2021188236-A1

Title: Brake system for a vehicle

Description:
FIELD OF THE INVENTION 
     The present invention relates to a brake system for a vehicle, to a vehicle with the brake system, and to a method of controlling a brake system for a vehicle. 
     BACKGROUND INFORMATION 
     Autonomous or near-autonomous operation of transport vehicles is a relatively new field of technology. More sophisticated functions require special hardware infrastructure. For example, present commercial vehicle systems require the presence and attention of a driver. However, in the future the driver will be less involved in the driving control task of the vehicle, and automated systems are supposed to take over more significant driving functions, which requires increased reliability levels and consequently different types of system redundancies. 
     Commercial vehicles conventionally use electro-pneumatic or by-wire brake systems, wherein the electronic part of the control is realized as a single-circuit control. In case of malfunction of the control electronics, the driver is able to control the pneumatic part of the brake system by their foot because a two-circuit pneumatic backup system still is available. In case of highly automated vehicles where the driver is not in the control loop anymore, or even not available or present in the vehicle, the above brake system would be unsatisfactory, since there is no arrangement/structure which would substitute the brake control by the driver in case of malfunction of the single electronic control circuit. Therefore some redundancy is to be added to the control of a brake system. 
     Patent document DE 10 2008 009 043 B3 discusses a redundant brake system for a commercial vehicle. The system utilizes a parking brake integrated into an air supply unit as a redundant brake actuator. For axles not equipped with spring parking brake chambers, a control output of a trailer control module is used as pneumatic control input of axle modulators. 
     SUMMARY OF THE INVENTION 
     Against this background, it is an object of the present invention to provide an improved brake system for a vehicle, an improved vehicle with the brake system, and an improved method of controlling a brake system for a vehicle. 
     This object may be achieved by a brake system for a vehicle, by a vehicle with the brake system, and by a method of controlling a brake system for a vehicle according to the main claims. 
     According to embodiments, for example, there may be provided a redundant brake system or brake system with redundancy for a vehicle by way of a redundant foot brake sensor and associated pressure modulators redundantly performing service brake functions. In particular, a foot brake module (FBM) may be split into two main components used to provide redundancy for brake actuation. More specifically, one of the main components may be a redundant foot brake sensor arranged in a cabin of the vehicle, and the other of the main components may comprise pressure modulators, which may be placed on a chassis frame or directly on backup ports of electronic pressure modulators (EPM) or axle pressure modulators, for example. In other words, for example, a split foot brake modulator may provide additional redundancy for the brake system. 
     Advantageously, according to embodiments, additional redundancy can be provided by making minimum changes to a state-of-the-art brake system. Hence, costs for providing redundancy can be minimized. In particular, electric redundancy can be ensured, as opposed to pneumatically redundancy provided in conventional brake systems. Furthermore, the proposed redundant brake system has a pneumatic layout appropriate for autonomous driving applications. Thus, for example, failsafe operation of a vehicle brake system can be provided both electrically and pneumatically. 
     A brake system for a vehicle comprises:
         a first electric power supply unit and a second electric power supply unit;   an electronic brake control unit, wherein the electronic brake control unit is connected to the first electric power supply unit;   a first axle pressure modulator for service brake chambers associated with a first axle of the vehicle, wherein the first axle pressure modulator is connected to the electronic brake control unit;   a second axle pressure modulator for spring brake cylinders associated with a second axle of the vehicle, wherein the second axle pressure modulator is connected to the electronic brake control unit;   a redundant brake pedal sensor, wherein the redundant brake pedal sensor is connected to the electronic brake control unit; and   a first pressure modulator and a second pressure modulator, wherein the first pressure modulator and the second pressure modulator are connected to the second electric power supply unit and to the redundant brake pedal sensor, wherein the first pressure modulator is fluidically connected to the first axle pressure modulator, wherein the second pressure modulator is fluidically connected to the second axle pressure modulator, wherein the redundant brake pedal sensor is configured to issue a first control signal for the electronic brake control unit and a second control signal for controlling the first pressure modulator and the second pressure modulator, wherein the first pressure modulator is configured to command pneumatic control pressure for the first axle pressure modulator depending on the second control signal from the redundant brake pedal sensor, wherein the second pressure modulator is configured to command pneumatic control pressure for the second axle pressure modulator depending on the second control signal from the redundant brake pedal sensor.       

     The vehicle may be a utility vehicle or commercial vehicle, for example a truck, bus or the like. The service brake chambers and the spring brake cylinders may represent brake actuators of the brake system. The electric power supply units may be batteries. The first and second pressure modulators may comprise electronics, which may be configured to read and interpret the control signal from the redundant foot brake sensor and translate it into a pneumatic pressure demand for brake application. The brake system may also comprise an electronic parking brake controller. The electronic parking brake controller may be connected to the second electric power supply unit. The electronic parking brake controller may be fluidically connected to the spring brake cylinders. 
     According to an embodiment, the first electric power supply unit and the electronic brake control unit may form part of a first service brake subsystem. The second electric power supply unit, the first pressure modulator and the second pressure modulator may form part of a second service brake subsystem. In the event of a malfunction of the first service brake subsystem, the second service brake subsystem may be usable as a redundant service brake subsystem. In other words, the second service brake subsystem may be used to redundantly perform service brake functions in the event of a malfunction of the first service brake subsystem. In particular, the first pressure modulator and the second pressure modulator may be used instead of the electronic brake control unit to perform service brake functions in the event of a malfunction of the first service brake subsystem. A brake subsystem may also be referred to as a brake circuit. Such an embodiment offers the advantage that redundancy can be added to the brake system to enhance safety, in particular for autonomous driving applications. 
     According to an embodiment, the redundant brake pedal sensor may be configured to issue the control signals as electric signals. The first pressure modulator may be configured to command the pneumatic control pressure as a proportional pressure. The second pressure modulator may be configured to command the pneumatic control pressure as a proportional pressure. Such an embodiment offers the advantage that electric redundancy can be provided in a reliable and simple manner. 
     According to an embodiment, the first pressure modulator may be arranged closer to the first axle pressure modulator than to the redundant brake pedal sensor. The second pressure modulator may be arrangeable or arranged closer to the second axle pressure modulator than to the redundant brake pedal sensor. The redundant brake pedal sensor may be arrangeable or arranged in a cabin of the vehicle. Such an embodiment offers the advantage that pneumatic lines can be eliminated from the cabin of the vehicle. 
     According to an embodiment, the first pressure modulator may be configured to control a backup port of the first axle pressure modulator. The second pressure modulator may be configured to control a backup port of the second axle pressure modulator. Such an embodiment offers the advantage that the control pressure the axle pressure modulators can be commanded in a reliable and simple manner. 
     According to an embodiment, the first pressure modulator and the second pressure modulator may be combined in a modulator unit. The modulator unit may be mountable or mounted to a chassis frame of the vehicle. Such an embodiment offers the advantage that manufacturing costs can be reduced because only one unit is to be installed. 
     According to an embodiment, the redundant brake pedal sensor may be configured to issue the control signals via electric lines or via a wireless connection. Correspondingly, the pressure modulators may be configured to receive the control signals via electric lines or via a wireless connection. Such an embodiment offers the advantage that the control signals can be transmitted safely and reliably according to a vehicle requirements. 
     According to an embodiment, the brake system may comprise a trailer control module for controlling braking functions of a trailer of the vehicle. The trailer control module may be connected to the electronic brake control unit. An electronic parking brake controller may be fluidically connected to the trailer control module. Such an embodiment offers the advantage that also a trailer may be connected to the vehicle, which acts as a tractor, and reliably connected to the redundant brake system. 
     According to an embodiment, the brake system may comprise a third pressure modulator. The third pressure modulator may be fluidically connected to the trailer control module. The third pressure modulator may be connected to the redundant brake pedal sensor. The redundant brake pedal sensor may be configured to issue the second control signal for controlling the third pressure modulator. The third pressure modulator may be configured to pneumatically control the trailer control module depending on the second control signal from the redundant brake pedal sensor. The third pressure modulator unit may be arrangeable or arranged closer to the trailer control module than to the redundant brake pedal sensor. Such an embodiment offers the advantage that the redundant execution of service brake functions can also be implemented in a simple and reliable manner for a trailer connected to the vehicle as a tractor. Furthermore, brake application can be controlled independently for tractor and trailer. 
     According to an embodiment, the third pressure modulator may be configured to pneumatically control the trailer control module depending on trailer load. Such an embodiment offers the advantage that electric redundancy may be provided in a simple and reliable manner not only for a vehicle used as a tractor but also for a trailer. 
     A vehicle comprises:
         an embodiment of the aforementioned the brake system;   the first axle, with which the first axle pressure modulator of the brake system is associated; and   the second axle, with which the second axle pressure modulator of the brake system is associated.       

     The first axle pressure modulator may be mounted in the vicinity of the first axle. Further elements of the brake system associated with the first axle pressure modulator, such as the first pressure modulator, the service brake chambers and valves, may also be mounted in the vicinity of the first axle. The second axle pressure modulator may be mounted in the vicinity of the second axle. Further elements of the brake system associated with the second axle pressure modulator, such as the second pressure modulator, the spring brake cylinders, may also be mounted in the vicinity of the second axle. 
     A method of controlling a brake system for a vehicle, wherein the brake system is an embodiment of the aforementioned brake system, comprises:
         receiving an error signal representing a malfunction of the first electric power supply unit, the electronic brake control unit, the first axle pressure modulator or the second axle pressure modulator or a malfunction of the second electric power supply unit, the first pressure modulator or the second pressure modulator; and   transmitting service brake commands of the vehicle to the first pressure modulator and the second pressure modulator in the event of a malfunction of the first electric power supply unit, the electronic brake control unit, the first axle pressure modulator or the second axle pressure modulator or to the electronic brake control unit in the event of a malfunction of the second electric power supply unit, the first pressure modulator or the second pressure modulator.       

     The method or the steps of the method may be executed using a controller. Thus, the method may be executed to control an embodiment of the aforementioned brake system. 
     Embodiments of the approach presented here shall be explained in greater detail in the subsequent description with reference to the figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a schematic illustration of a vehicle comprising a brake system according to an embodiment of the present invention. 
         FIG. 2  shows a schematic illustration of a brake system according to an embodiment of the present invention. 
         FIG. 3  shows a schematic illustration of a brake system according to an embodiment of the present invention. 
         FIG. 4  shows a schematic illustration of a brake system according to an embodiment of the present invention. 
         FIG. 5  shows a flowchart of a method of controlling a brake system according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description of advantageous embodiments of the present invention, the same or similar reference numerals shall be used for the elements depicted in the various figures and acting in a similar way, wherein repeated description of these elements shall be omitted. 
       FIG. 1  shows a schematic illustration of a vehicle  100  comprising a brake system  110  according to an embodiment of the present invention. The vehicle  100  is a utility vehicle or commercial vehicle, such as a truck. The vehicle  100  comprises a first axle  102  and a second axle  104 , according to this embodiment. Furthermore, the vehicle  100  comprises a controller  106  and the brake system  110 . The controller  106  is configured to control the brake system  110  by a command signal  108 . In particular, the command signal  108  represents service brake commands for performing service brake functions of the brake system  110 . Alternatively, the controller  106  also be part of the brake system  110 . 
     The brake system  110  comprises a first service brake subsystem  112  and a second service brake subsystem  114 . The first service brake subsystem  112  is configured to perform service brake functions of the brake system. The second service brake subsystem  114  is configured to perform service brake functions of the brake system  110  as a backup or to provide redundancy instead of the first service brake subsystem  112 . 
     The brake system  110  further comprises a monitoring device  116  for monitoring a state of health of the first service brake subsystem  112  and the second service brake subsystem  114 . Alternatively, the monitoring device  116  may also be part of a system other than the brake system  110 . The monitoring device  116  is connected to the first service brake subsystem  112  and to the second service brake subsystem  114 . The monitoring device  116  is configured to detect a potential malfunction of the first service brake subsystem  112  or of the second service brake subsystem  114 . The monitoring device  116  is configured to output an error signal  118  to the controller  106 . The error signal  118  represents a malfunction of the first service brake subsystem  112  or of the second service brake subsystem  114 . 
     In response to the error signal  118 , the controller  106  is configured to transmit the command signal  108  to either the first service brake subsystem  112  or the second service brake subsystem  114 . More specifically, the controller  106  is configured to transmit the command signal  108  to that subsystem  112  or  114  free from malfunction, as indicated by the error signal  118 . 
       FIG. 2  shows a schematic illustration of a brake system  110  according to an embodiment of the present invention. The brake system  110  is a brake system  110  for a vehicle, specifically a commercial vehicle or utility vehicle, e.g. a truck. The brake system  110  corresponds or is similar to the brake system shown in  FIG. 1 . 
     The brake system  110  comprises a first electric power supply unit  221 , a second electric power supply unit  222 , an electronic brake control unit  223 , a redundant brake pedal sensor  225 , a first or front axle pressure modulator  229 , a second or rear axle pressure modulator  230 , two service brake chambers  232 , two spring brake cylinders  233 , a first pressure modulator  234  and a second pressure modulator  235 . According to this embodiment, the brake system  110  further comprises an electronic parking brake controller  224 , a park brake lever sensor  226 , a trailer control module  228 , two pressure control valves  231 , a first compressed air supply module  241 , a second compressed air supply module  242  and a third compressed air supply module  243 . 
     The first electric power supply unit  221  and the electronic brake control unit  223  form part of the first service brake subsystem described with reference to  FIG. 1 . The second electric power supply unit  222 , the redundant brake pedal sensor  225 , the first pressure modulator  234  and the second pressure modulator  235  form part of the second service brake subsystem described with reference to  FIG. 1 . In the event of a malfunction of the first service brake subsystem, the second service brake subsystem is usable as a redundant service brake subsystem, or in other words to perform service brake functions of the brake system  110 . 
     The first electric power supply unit  221  is electrically connected to the electronic brake control unit  223 . The electronic brake control unit  223  is electrically connected to the first axle pressure modulator  229  via an analogous electric signal and supply line and via a digital electric signal line. Furthermore, the electronic brake control unit  223  is electrically connected to the second axle pressure modulator  230  via an analogous electric signal and supply line and via a digital electric signal line. Also, the electronic brake control unit  223  is electrically connected to the pressure control valves  231 , to the trailer control module  228  and to the redundant brake pedal sensor  225  via analogous electric signal and supply lines. 
     The first axle pressure modulator  229  is fluidically connected to the first compressed air supply module  241  via a pneumatic supply line. Also, the first axle pressure modulator  229  is fluidically connected to the pressure control valves  231  via pneumatic service brake control lines. Each of the pressure control valves  231  is fluidically connected to a respective one of the service brake chambers  232  via a pneumatic service brake control line. The first axle pressure modulator  229 , the control valves  231  and the service brake chambers  232  are associated with a first axle of the vehicle. Furthermore, the first axle pressure modulator  229  is electrically connected to a group of brake sensors for the first axle via analogous electric signal and supply lines. 
     The second axle pressure modulator  230  is fluidically connected to the second compressed air supply module  242  via a pneumatic supply line. Furthermore, the second axle pressure modulator  230  is fluidically connected to the spring brake cylinders  233  via pneumatic service brake control lines. The second axle pressure modulator  230  and the spring brake cylinders  233  are associated with a second axle of the vehicle. Also, the second axle pressure modulator  230  is electrically connected to a group of brake sensors for the second axle via analogous electric signal and supply lines. 
     The second electric power supply unit  222  is electrically connected to the electronic parking brake controller  224 , the first pressure modulator  234  and the second pressure modulator  235 . The electronic parking brake controller  224  is electrically connected to the first pressure modulator  234  and the second pressure modulator  235  via analogous electric signal and supply lines. Furthermore, the electronic parking brake controller  224  is electrically connected to the park brake lever sensor  226  via an analogous electric signal and supply line. The electronic parking brake controller  224  is fluidically connected to the spring brake cylinders  233  via pneumatic parking brake control lines. Also, the electronic parking brake controller  224  is fluidically connected to the trailer control module  228  via a pneumatic parking brake control line. 
     The redundant brake pedal sensor  225  is configured to issue a first control signal for the electronic brake control unit  223 . In particular, the redundant brake pedal sensor  225  is configured to issue the first control signal as an electric signal. The redundant brake pedal sensor  225  is electrically connected to the first pressure modulator  234  via an analogous electric signal and supply line. Also, the redundant brake pedal sensor  225  is electrically connected to the second pressure modulator  235  via an analogous electric signal and supply line. The redundant brake pedal sensor  225  is configured to issue a second control signal for controlling the first pressure modulator  234  and the second pressure modulator  235 . In particular, the redundant brake pedal sensor  225  is configured to issue the second control signal as an electric signal. Alternatively, the redundant brake pedal sensor  225  is configured to issue the control signals via a wireless connection instead of via electric lines. 
     The first pressure modulator  234  is fluidically connected to the first compressed air supply module  241  via a pneumatic supply line. Furthermore, the first pressure modulator  234  is fluidically connected to the first axle pressure modulator  229  via a pneumatic service brake control line. The first pressure modulator  234  is configured to command pneumatic control pressure for the first axle pressure modulator  229  depending on the second control signal from the redundant brake pedal sensor  225 . In particular, the first pressure modulator  234  is configured to command the pneumatic control pressure as a proportional pressure. More specifically, the first pressure modulator  234  is configured to control a backup port of the first axle pressure modulator  229 . The first pressure modulator  234  is arranged closer to the first axle pressure modulator  229  than to the redundant brake pedal sensor  225 . In particular, the first pressure modulator  234  may be arranged on the backup port of the first axle pressure modulator  229 . 
     The second pressure modulator  235  is fluidically connected to the second compressed air supply module  242  via a pneumatic supply line. Furthermore, the second pressure modulator  235  is fluidically connected to the second axle pressure modulator  230  via a pneumatic service brake control line. The second pressure modulator  235  is configured to command pneumatic control pressure for the second axle pressure modulator  230  depending on the second control signal from the redundant brake pedal sensor  225 . In particular, the second pressure modulator  235  is configured to command the pneumatic control pressure as a proportional pressure. More specifically, the second pressure modulator  235  is configured to control a backup port of the second axle pressure modulator  230 . The second pressure modulator  235  is arranged closer to the second axle pressure modulator  230  than to the redundant brake pedal sensor  225 . In particular, the second pressure modulator  235  may be arranged on the backup port of the second axle pressure modulator  230 . 
     The trailer control module  228  is configured to control braking functions of a trailer coupled to the vehicle. The trailer control module  228  is fluidically connected to the third compressed air supply module  243  via pneumatic supply line. 
     In other words,  FIG. 2  shows an architecture of a brake system  110  commercial, which may also be referred to as a schematic a redundant commercial vehicle electronic or electro-pneumatic brake system  110  (EBS). The electro-pneumatic brake system  110  comprises the following main components. The brake system  110  is redundantly supplied by the electric power supply units  221  and  222 , which may be batteries. The EBS electronic brake control unit  223  is supplied from the first electric power supply unit  221  or first battery  221 . The electronic brake control unit  223  is configured to electronically control the front or first axle pressure modulator  229 , the pressure control valves  231  on the front or first axle, the rear or second axle pressure modulator  230  and the trailer control module  228 . Front or first axle wheel brakes are actuated by the service brake chambers  232 . Rear or second axle wheel brakes are actuated by the spring brake cylinders  233  or spring brake combi cylinders. 
     The redundant pair of the brake system  110  is provided by the electronic redundant foot brake modulators (rFBM), i.e. the first pressure modulator  234  and the second pressure modulator  235 , which are actuating the backup ports of the front or first axle pressure modulator  229  and the rear or second axle pressure modulator  230 . In particular, the redundant brake architecture describes a redundant brake-by-wire system as the brake system  110 , wherein pneumatic components are eliminated from the cabin of the vehicle, and the pneumatic part of the foot brake module, i.e. the first pressure modulator  234  and the second pressure modulator  235 , can be installed near the first and second axle modulators  229  and  230  to reduce pneumatic pipes and improve system response. Outputs of the of the rFBM modules, i.e. the first pressure modulator  234  and the second pressure modulator  235 , provide pneumatic command for the first and second axle modulators  229  and  230 . Service brakes can be commanded by the driver by the redundant brake pedal sensor  225 , which provides separate demand signals for both the electronic brake control unit  223  and the first and second pressure modulators  234  and  235 . The first and second pressure modulators  234  and  235  can be standalone units or integrated into any other modules like a compressed air processing unit or standalone electronic parking brake controller  224 . Furthermore, according to another embodiment, the first and second pressure modulators  234  and  235  can be integrated into the first and second axle modulators  229  and  230 , respectively. 
     When the brake system  110  is fully intact, the service brake is controlled by the electronic brake control unit  223  as a master. The electronic brake control unit  223  electronically controls the first and second axle pressure modulators  229  and  230  and the trailer control module  228 . In case of a malfunction of the electronic brake control unit  223  or the first electric power supply unit  221 , brake control is taken over by the first and second pressure modulators  234  and  235 , and axles equipped with the first and second axle modulators  229  and  230  are controlled pneumatically through the backup ports of the first and second axle modulators  229  and  230 . In case the first and second pressure modulators  234  and  235  or the second electric power supply unit  222  has any malfunction, the electronic brake control unit  223  is configured to control the brake system  110  as in the normal case. A parking brake function can also be temporally simulated in this case by way of service brake actuation. 
       FIG. 3  shows a schematic illustration of a brake system  110  according to an embodiment of the present invention. The brake system  110  shown in  FIG. 3  corresponds to the brake system shown in  FIG. 2  with the exception of the first pressure modulator and the second pressure modulator both combined in a single modulator unit  334 . The modulator unit  334  comprises the first pressure modulator and the second pressure modulator or functions as the pressure modulator and the second pressure modulator. Furthermore, the modulator unit  334  comprises an electronic control unit (ECU). 
     The modulator unit  334  is mounted to a chassis frame of the vehicle  100 , for example. Pneumatic ports of the modulator unit  334  are connected to the backup ports of the first and second axle modulators  229  and  230 . According to this embodiment, only one additional unit, i.e. the modulator unit  334 , needs to be installed in the vehicle, thus optimizing manufacturing costs. In other words, in a centralized version, a single modulator unit  334  or actuator unit is installed in the vehicle. A number of channels of the modulator unit  334  may vary according to vehicle configuration. 
       FIG. 4  shows a schematic illustration of a brake system  110  according to an embodiment of the present invention. The brake system  110  shown in  FIG. 4  corresponds to the brake system shown in  FIG. 2  with the exception of a third pressure modulator  436 . 
     The third pressure modulator  436  is fluidically connected to the trailer control module  228  via a pneumatic service brake control line. The third pressure modulator  436  is electrically connected to the second electric power supply unit  222 . Also, the third pressure modulator  436  is electrically connected to the redundant brake pedal sensor  225  via an analogous electric signal and supply line. The redundant brake pedal sensor  225  is configured to issue the second control signal for controlling the third pressure modulator  436 . The third pressure modulator  436  is configured to pneumatically control the trailer control module  228  depending on the second control signal from the redundant brake pedal sensor  225 . For example, the third pressure modulator  436  is configured to pneumatically control the trailer control module  228  depending on trailer load. In particular, the third pressure modulator unit  436  is arranged closer to the trailer control module  228  than to the redundant brake pedal sensor  225 . 
     According to this embodiment, because the third pressure modulator  436  is installed for the trailer control module  228 , the control pressure for the trailer can be modulated independently. 
       FIG. 5  shows a flowchart of a method  500  of controlling a brake system according to an embodiment of the present invention. The method  500  is executable in connection with the brake system as described with reference to one of the preceding figures or a similar brake system. 
     In general, the method  500  can be executed in connection with a brake system for a vehicle. Such a brake system comprises a first electric power supply unit and a second electric power supply unit, an electronic brake control unit, wherein the electronic brake control unit is connected to the first electric power supply unit, a first axle pressure modulator for service brake chambers associated with a first axle of the vehicle, wherein the first axle pressure modulator is connected to the electronic brake control unit, a second axle pressure modulator for spring brake cylinders associated with a second axle of the vehicle, wherein the second axle pressure modulator is connected to the electronic brake control unit, a redundant brake pedal sensor, wherein the redundant brake pedal sensor is connected to the electronic brake control unit, and a first pressure modulator and a second pressure modulator, wherein the first pressure modulator and the second pressure modulator are connected to the second electric power supply unit and to the redundant brake pedal sensor, wherein the first pressure modulator is fluidically connected to the first axle pressure modulator, wherein the second pressure modulator is fluidically connected to the second axle pressure modulator, wherein the redundant brake pedal sensor is configured to issue a first control signal for the electronic brake control unit and a second control signal for controlling the first pressure modulator and the second pressure modulator, wherein the first pressure modulator is configured to command pneumatic control pressure for the first axle pressure modulator depending on the second control signal from the redundant brake pedal sensor, wherein the second pressure modulator is configured to command pneumatic control pressure for the second axle pressure modulator depending on the second control signal from the redundant brake pedal sensor. 
     The method  500  of controlling comprises a step  510  of receiving an error signal representing a malfunction of the first electric power supply unit, the electronic brake control unit, the first axle pressure modulator or the second axle pressure modulator or a malfunction of the second electric power supply unit, the first pressure modulator or the second pressure modulator. Furthermore, the method  500  of controlling comprises a step  520  of transmitting service brake commands of the vehicle to the first pressure modulator and the second pressure modulator in the event of a malfunction of the first electric power supply unit, the electronic brake control unit, the first axle pressure modulator or the second axle pressure modulator or to the electronic brake control unit in the event of a malfunction of the second electric power supply unit, the first pressure modulator or the second pressure modulator. 
     With reference to the aforementioned figures, according to an embodiment, there may be provided a brake system  110  for a vehicle  100 , wherein a redundant brake circuit is equipped with an electrified foot brake module, in which the redundant foot brake sensor  225  or sensor unit is separated from the pressure modulators  234 ,  235 ,  334  and/or  436  or actuator parts, wherein communication therebetween is effected by an electronic arrangement/structure. 
     THE REFERENCE NUMERAL LIST IS AS FOLLOWS 
       100  vehicle 
       102  first axle 
       104  second axle 
       106  controller 
       108  command signal 
       110  brake system 
       112  first service brake subsystem 
       114  second service brake subsystem 
       116  monitoring device 
       118  error signal 
       221  first electric power supply unit 
       222  second electric power supply unit 
       223  electronic brake control unit 
       224  electronic parking brake controller 
       225  redundant brake pedal sensor 
       226  park brake lever sensor 
       228  trailer control module 
       229  first axle pressure modulator 
       230  second axle pressure modulator 
       231  pressure control valve 
       232  service brake chamber 
       233  spring brake cylinder 
       234  first pressure modulator 
       235  second pressure modulator 
       241  first compressed air supply module 
       242  second compressed air supply module 
       243  third compressed air supply module 
       334  modulator unit 
       436  third pressure modulator 
       500  method of controlling 
       510  step of receiving 
       520  step of transmitting