VEHICLE WITH A FAULT-TOLERANT ELECTRONIC BRAKE-BY-WIRE (BBW) SYSTEM

Abstract

Vehicle (100) with a fault-tolerant electronic brake-by-wire (BBW) system (102), the vehicle (100) comprising: a plurality of braking systems (118a, 118b, 118c, 118d) configured to control the braking of a respective wheel (112a, 112b, 114a, 114b) of the vehicle (100), the plurality of braking systems (118a, 118b, 118c, 118d) comprising: a first braking system (118b) integrated into a first improved brake actuator assembly (205a) having a first electronic actuator driver circuit (202b) in signal communication with a first electromechanical actuator (120b) configured to adjust a braking force applied to a first wheel (112b) of the vehicle (100); and a second braking system (118a) integrated into a first improved intelligent brake actuator assembly (203a) having a first actuator controller (201a) in signal communication with a second electronic actuator driver circuit (202a), the second electronic actuator driver circuit (202a) being in signal communication with a second electromechanical actuator (120a) configured to adjust a braking force applied to a second wheel (112a) of the vehicle (100); characterized by a third brake system (118d) including a second improved brake actuator assembly (205b), and a fourth brake system (118c) including a second improved intelligent brake actuator assembly (203b), wherein the first improved intelligent brake actuator assembly (203a) is in signal communication with the first improved brake actuator assembly (205a) and the second improved intelligent brake actuator assembly (203b), and wherein the second improved intelligent brake actuator assembly (203b) is in signal communication with the second improved brake actuator assembly (205b) and the first improved intelligent brake actuator assembly (203a).

Description

FIELD OF THE INVENTION

[0001] The invention disclosed herein relates generally to a vehicle according to the preamble of claim 1 with a fault-tolerant electronic brake-by-wire (BBW) system, as is essentially known from DE 195 21 175 C1.

[0002] A similar system also emerges from DE 103 16 452 A1. BACKGROUND

[0003] Current automotive industry trends toward reducing the number of total mechanical components and overall vehicle weight have contributed to the development of system-by-wire applications, typically referred to as X-by-wire systems. One such X-by-wire system that has received more attention is a brake-by-wire (BBW) system, sometimes referred to as an electronic braking system (EBS).

[0004] Unlike conventional mechanical braking systems, BBW systems actuate one or more vehicle braking components via an electrical signal generated by an onboard processor / controller. In some systems, a BBW system is implemented by replacing a conventional hydraulic fluid-based service braking system with an electrically based system to perform basic braking functions. The electrical systems implemented in a conventional BBW system include braking systems with an electronic brake actuator, such as an electronically controlled caliper, typically referred to as an "e-caliper." Conventional e-calipers eliminate any control logic and operate solely in response to current generated by a single power source located external to the braking system and in a remote area of ​​the vehicle.

[0005] Because brake control systems typically eliminate any direct mechanical connections and / or hydraulic power transmission paths between the vehicle operator and the brake control units, considerable attention has been paid to the design of brake control systems and control architectures that ensure reliable and robust operation. Various design techniques have been implemented to promote brake control system reliability, including, for example, redundancy, fault tolerance to undesirable events (e.g., events affecting control signals, data, hardware, software, or other elements of such systems), fault monitoring, and recovery.

[0006] The invention is therefore based on the object of DE 195 21 175 C1 to provide a vehicle with an electronic brake-by-wire (BBW) system which, among other things, has improved fault tolerance. SUMMARY

[0007] This object is achieved by a vehicle having the features of claim 1.

[0008] Further described is a vehicle having another fault-tolerant electronic brake braking system. The vehicle includes a plurality of braking systems configured to control braking of a respective wheel of the vehicle. The plurality of braking systems includes a first group of braking systems and a second group of braking systems. Each braking system of the first group is integrated with an electronically enhanced brake actuator assembly. Each braking system of the second group is integrated with an electronically enhanced intelligent brake actuator assembly that includes an electronic actuator controller. Each of the enhanced brake actuator assemblies of the first group excludes an electronic actuator controller.The improved intelligent brake actuator assemblies electrically control a respective brake system integrated therein and at least one improved brake actuator assembly integrated into the first group of brake systems.

[0009] Furthermore, a method for controlling a fault-tolerant brake braking system is described. This method includes integrating an improved intelligent brake actuator assembly including an electronic actuator controller into a first braking system and integrating an improved intelligent brake actuator assembly excluding the electronic actuator controller into a second braking system. The method further includes outputting at least one data command signal via the electronic actuator controller that controls the braking of a first wheel connected to the first braking system and the braking of a second wheel connected to a second braking system.

[0010] The above-mentioned features and advantages will be readily apparent from the following detailed description of the invention when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Other features and details appear only by way of example in the following detailed description of the embodiments and the detailed description, which refers to the following drawings, in which: Fig. 1 is a schematic plan view of a vehicle incorporating a fault-tolerant BBW system according to an embodiment; Fig. 2 shows a first braking system having an improved intelligent brake actuator arrangement with an actuator control in electrical communication with a second braking system having an improved intelligent brake actuator arrangement which excludes an actuator control; Fig. 3A is a schematic view of a BBW system based on a split EBS control topology according to one embodiment; Fig. 3B is a schematic view of a BBW system based on a full EBS control topology according to one embodiment; and Fig. 4 is a flowchart illustrating a method for controlling a fault-tolerant BBW system according to one embodiment. DESCRIPTION OF THE EMBODIMENTS

[0012] Various embodiments provide a BBW system including an "enhanced smart" brake actuator assembly and an "enhanced" brake actuator assembly. The improved smart brake actuator assembly and the improved brake actuator assembly both include electronic actuator driver circuitry integrated therein. However, the improved smart brake actuator assembly includes an actuator controller (not included in the improved brake actuator assembly). Accordingly, the actuator controller is capable of controlling both the improved smart brake actuator assembly and the improved brake actuator assembly. Integrating the actuator driver circuitry and the electromechanical actuators into a single device also reduces the length and number of high-power, high-frequency switched power signals installed in the vehicle.In this way, the level of unintended electromagnetic compatibility (EMC) (e.g. generation, propagation and reception of electromagnetic energy) associated with the vehicle can be reduced.

[0013] With reference to Fig. 1 illustrates a vehicle 100 having a fault-tolerant braking and braking system 102 configured to electronically control braking of the vehicle 100, according to one embodiment. The vehicle 100 is propelled via a powertrain system including an engine 104, a transmission 108, and a transfer case 110. The engine 104 includes, for example, an internal combustion engine configured to generate drive torque that drives the front wheels 112a and 112b and the rear wheels 114a and 114b using various components of the vehicle's propulsion system. Various types of engines 104 may be used in the vehicle 100, including, but not limited to, a diesel engine, a gasoline engine, and a hybrid engine system that combines an internal combustion engine with, for example, an electric motor.The fault-tolerant BBW system 102 can also be implemented in a battery-powered electric vehicle with an electric motor without departing from the scope of the invention. The vehicle powertrain can be understood to include the various powertrain components, with the exception of the engine 104. According to one embodiment, the engine drive torque is transmitted to the transmission 108 via a rotatable crankshaft (not shown). Thus, the torque delivered to the transmission 108 can be adjusted in various ways, including, for example, by controlling the operation of the engine 104, as will be understood by those skilled in the art.

[0014] The fault-tolerant BBW system 102 (hereinafter referred to as BBW system 102) includes a pedal assembly 116, brake assemblies 118a-118d (i.e., brake corner modules), one or more actuator units 120a-120d, one or more wheel sensors 122a and 122b, and an electronic braking system (EBS) controller 200. In at least one embodiment, the brake actuators 120a-120d include one or more enhanced smart brake actuator assemblies and one or more enhanced brake actuators, as discussed in more detail herein.

[0015] The pedal assembly 116 includes a brake pedal 124, a pedal pressure sensor 126, and a pedal travel sensor 128. The pedal assembly 116 may be any combination of hardware and software. For example, the pedal assembly 116 may be a pedal emulator that implements the feel of a conventional brake pedal into a hydraulic braking system. In at least one embodiment, the pedal assembly 116 may be operated solely using electronic wiring and hardware controls executing brake logic software.

[0016] A braking distance or braking force applied to the brake pedal 124 may be determined based on respective signals output from the pedal pressure sensor 126 and a pedal travel sensor 128, as understood by one of ordinary skill in the art. According to an exemplary embodiment, the pedal pressure sensor 126 is implemented as a pressure transducer or other suitable pressure sensor configured to precisely detect, measure, or otherwise determine a pressure or force applied to the brake pedal 124 by the operator of the vehicle 100. The pedal travel sensor 128 may be configured or set as a pedal position and range sensor such that it precisely detects, measures, or otherwise determines the relative position and direction of travel of the brake pedal 124 along a fixed range of travel when the brake pedal 124 is depressed or applied.

[0017] The measurements or readings obtained by pedal pressure sensor 126 and pedal travel sensor 128 are communicable as required for use with one or more braking algorithms and / or logic software stored in the memory of an electronic controller. The data from pedal pressure sensor 126 and / or pedal travel sensor 128 may also be used to calculate, select, and / or otherwise determine an appropriate braking request or event in response to the sensed and recorded measurements or reading outputs from wheel sensors 122a and 122b. Based on the determined braking request or event, EBS controller 200 may execute various braking algorithms, speed calculations, distance-to-brake calculations, etc. Additionally, EBS controller 200 may control various braking mechanisms or systems, such as an electronic emergency brake.

[0018] The wheel sensors 122a and 122b can provide various types of vehicle data, including, but not limited to, speed, acceleration, deceleration, vehicle angle relative to the surface, and wheel slip. In at least one embodiment, the BBW system 102 can include one or more object detection sensors 129 located at various locations on the vehicle 100. The object detection sensors 129 are configured to detect the movement and / or existence of various objects surrounding the vehicle, including, but not limited to, surrounding vehicles, pedestrians, traffic signs, and roadway hazards. The object detection sensors 129 can provide data indicating a scenario (e.g., a requirement) to decelerate or stop the vehicle based on the proximity of one or more objects relative to the vehicle 100.In response to the determination of the braking scenario, one or more braking systems 118a-118d may be controlled to decelerate or stop the vehicle 100, as discussed in more detail herein.

[0019] According to at least one embodiment, the BBW system 102 may also include a separation module (not shown in Fig. 1) and one or more power sources (not shown in Fig. 1). The isolation module may be embodied as an electrical circuit and is configured to isolate circuit faults, such as wire-to-wire shorts, that occur on a signal line loop (SLC). The isolation module also limits the number of modules or detectors that can be disabled by a circuit fault on the SLC loop. The circuit fault may include, but is not limited to, short circuits, shorts to ground, and overvoltage.

[0020] According to one embodiment, when a circuit fault occurs, the isolation module may automatically create an open (disconnect) in the SLC loop to isolate the brake systems 118a-118d from a circuit fault condition. Additionally, when a power source fault occurs, the isolation module may disconnect the faulty power source while maintaining the remaining power sources. In this way, according to one embodiment, the BBW system 102 provides at least one fault-tolerant feature that may allow one or more brake systems 118a-118d to continue normal operation if a circuit fault condition occurs in the EBS system 102. When the circuit fault condition is resolved, the isolation module may automatically reconnect the isolated portion of the SLC loop, e.g., the brake systems 118a-118d, to the power source.

[0021] With reference to Fig. 2, an improved intelligent brake actuator assembly 203a is shown in signal communication with an improved brake actuator assembly 205a according to one embodiment. Although a single improved intelligent brake actuator assembly 203a and a single improved brake actuator assembly 205a are shown in Fig. 2, it is to be understood, however, that the remaining enhanced intelligent brake actuator units and the enhanced brake actuator assembly units included in the BBW system 102 may operate in a similar manner as described herein.

[0022] The improved intelligent brake actuator assembly 203a includes an actuator controller 201a, an electronically controlled actuator 120a, such as an electronic brake caliper (E-caliper) 120a, and an actuator driver circuit 202a, such as one or more electronic power circuits 202a. The combination of the actuator controller 201a, the actuator 120a, and the actuator driver circuit 202a as a single component provides fast, robust, short-circuit-proof, and diagnosable communication within the brake system 118a, while reducing data latency.

[0023] The actuator controller 201 selectively outputs a low-voltage data command signal (e.g., a low-voltage digital signal) in response to one or more braking events. The data command signal can be provided via a communication interface, including, but not limited to, FlexRay™, Ethernet, and a low-voltage message-based interface, such as a CAN (Controller Area Network) bus. FlexRay™ is a high-speed and fault-tolerant time-triggered protocol with static and dynamic frames. FlexRay™ can support high data rates of up to 10 Mbps.

[0024] The data command signal initiates actuator driver circuitry 202a, which is integrated into the enhanced intelligent brake actuator assembly 203a, or actuator driver circuitry 202b, which is integrated into the enhanced brake actuator assembly 205a. Thus, the overall component count and interconnect complexity of the BBW system 102 are reduced compared to conventional BBW systems. Additionally, implementing an actuator driver circuitry (e.g., 202a) locally within each respective brake assembly 118a-118d supports the elimination of long-distance, high-current jumper wires, thereby reducing or even eliminating EMI emissions typically encountered in conventional BBW systems.

[0025] Further with reference to Fig. 2, the actuator control 201a includes programmable memory (not in Fig. 1) and a microprocessor (not shown). The programmable memory can store flash software to provide flexibility for production implementation. In this way, the actuator controller 201 is capable of quickly executing the required control logic to implement and control the actuator driver circuits 202a and 202b (e.g., power circuits) by using a brake pedal transition logic method or algorithm programmed or stored in the memory.

[0026] The memory included in actuator controller 201a may be preloaded or preprogrammed with one or more brake torque lookup tables (LUTs) (i.e., brake torque data tables readily accessible by actuator controller 201a upon implementation or execution of a braking algorithm). In at least one embodiment, the brake torque LUT stores recorded measurements or readings of pedal assembly 116 and includes an associated commanded braking request for each of the sensed force measurements. Similarly, enhanced smart brake actuator assembly 203a stores a pedal position LUT corresponding to the measurements or readings monitored by brake system 116 and including a commanded braking request appropriate for the sensed position of pedal 124.

[0027] The improved brake actuator assembly 205a includes an electronically controlled actuator 120b, such as an electronic brake caliper (E-caliper) 120b, and an actuator driver circuit 202b, while excluding an actuator controller similar to that included in the improved smart brake actuator assembly 203a. Accordingly, the actuator driver circuit 202b is controlled by the actuator controller (e.g., 201a) included in one or more improved smart brake actuator assemblies (e.g., 203a). Therefore, the actuator controller 201a is capable of controlling both the respective improved smart brake actuator assembly 203a in which it is installed and the improved brake actuator assembly 205a, as discussed in more detail herein. Although Fig. 2 illustrates that the enhanced intelligent brake actuator assembly 203a controls a single enhanced brake actuator assembly 205a, the enhanced intelligent brake actuator assembly 203a may also control additional enhanced brake actuator assemblies included in the BBW system 102.

[0028] In Fig. 3A-3B, various embodiments of a BBW system 102 are shown. First, with reference to Fig. 3A (and also with temporary reference to Fig. 2) illustrates a BBW system 102 based on a split-control topology according to one embodiment. In at least one embodiment, the split-control topology includes a plurality of braking systems 118a-118d configured to brake a respective wheel 112a and 112b and 114a and 114b of the vehicle 100. According to an exemplary embodiment, the plurality of braking systems 118a-118d includes one or more braking systems 118a and 118c integrated with each of the enhanced intelligent brake actuator assemblies 203a and 203b, and one or more braking systems 118b and 118d integrated with each of the enhanced intelligent brake actuator assemblies 205a and 205b. A first improved intelligent brake actuator assembly 203a controls the braking of a first wheel 112a located on a driver side of the vehicle 100 (e.g.,the driver-side front wheel 112a) and a second enhanced intelligent brake actuator assembly 203b controls the braking of a second wheel 114b located on a passenger side of the vehicle 100 (e.g., the passenger-side rear wheel 114b).

[0029] The first improved brake actuator assembly 205a controls the braking of a third wheel 112b located on the passenger side of the vehicle 100 (e.g., the passenger-side front wheel 112b), and a second improved brake actuator assembly 205b controls the braking of a fourth wheel 114a located on the driver side of the vehicle 100 (e.g., the driver-side rear wheel 114a). It should be understood that the positions of the improved smart brake actuator assemblies 203a and 203b and improved brake actuator assemblies 205a and 205b are not limited to the positions illustrated in the drawings. For example, the positions (e.g., driver / passenger, front / rear) of the improved intelligent brake actuator assemblies 203a and 203b and the improved brake actuator assemblies 205a and 205b may be swapped or exchanged.

[0030] The improved intelligent brake actuator assemblies 203a and 203b include an actuator controller (element 201a. Fig. 2), an electronically controlled actuator (element 120a, Fig. 2) and an actuator driver circuit (element 202a, Fig. 2). A motor of the electronically controlled actuator 120a operates in response to a high-frequency switched, high-power current output by a respective actuator driver circuit and, in turn, drives the electronically controlled actuator to apply a variable (i.e., adjustable) braking force to decelerate a respective wheel 112a and 114a. The actuator driver circuits may include various high-power electronic components, including, but not limited to, H-bridges, heat sinks, application-specific integrated circuits (ASICs), Controller Area Network (CAN) transceivers, or temperature or current sensors.

[0031] The improved brake actuator assemblies 205a and 205b operate in a similar manner to the improved intelligent brake actuator assemblies 203a and 203b discussed herein. However, the improved brake actuator assemblies 205a and 205b are not integrated with a local actuator controller. Therefore, the actuator driver circuits included in the improved brake actuator assemblies 205a and 205b are controlled using low-voltage command signals output from one or more actuator controllers included in the improved intelligent brake actuator assemblies 203a and 203b.That is, the actuator controllers are configured to not only control the actuator driver circuits integrated into their respective enhanced intelligent brake actuator assemblies 203a and 203b, but are also configured to control the actuator driver circuits integrated into one or more enhanced brake actuator assemblies 205a and 205b.

[0032] The low-voltage command signal output by a respective actuator controller 201a, 201b may be provided to the enhanced brake actuator assemblies 205a and 205b via a communication interface. The communication interface may include, for example, FlexRay™, Ethernet, and a low-voltage message-based interface, such as a CAN bus. Because the individual actuator driver circuits are integrated into a respective brake system 118a-118d, the actuator driver circuits may be located in close proximity to their respective electronically controlled actuators (e.g., motors or e-brake calipers). In this way, the length of the high-current wires that provide the switching high-frequency current signals (shown as dashed arrows) for driving a respective electronically controlled actuator may be reduced.In at least one embodiment, the actuator driver circuit may be adjacent to or attached to a respective electronically controlled actuator to completely eliminate conventional high-current wires typically required to deliver switched, high-frequency, high-current signals.

[0033] How to continue in Fig. As illustrated in Figures 3A-3B, a first enhanced intelligent brake actuator assembly 203a is in electrical communication with a second enhanced intelligent brake actuator assembly 203b. In this way, the actuator controllers integrated into a respective enhanced intelligent brake actuator assembly 203a and 203b can share data. The shared data includes, for example, detected braking requests and diagnostic results obtained after performing self-diagnostic tests.

[0034] The actuator controllers 201a and 201b integrated into the respective enhanced intelligent brake actuator assemblies 203a and 203b are also capable of monitoring the condition of the vehicle 100 based on inputs from one or more sensors. The sensors include, but are not limited to, the wheel sensors 122a and 122b and data signals output from the pedal unit 116. The outputs of the pedal pressure sensor 126 and the pedal travel sensor 128 can be provided to each actuator controller 201a and 201b to provide output redundancy. Based on the condition of the vehicle 100, one or more enhanced intelligent brake actuator assemblies 203a and 203b can determine whether to invoke a braking event to decelerate and / or stop the vehicle 100.When a braking event is determined, one or more of the enhanced intelligent brake actuator assemblies 203a and 203b output a low voltage command signal that ultimately controls a braking force applied to the respective wheels 112a / 112b and 114a / 114b.

[0035] The actuator driver circuits (e.g., 202a) integrated into the enhanced intelligent brake actuator assemblies 203a and 203b and the enhanced brake actuator assemblies 205a and 205b receive a constant high-power input signal (e.g., unswitched high-power input current) from one or more power sources 204a and 204b. The high-power input signal may comprise a high-power current signal ranging from approximately 0 amperes to approximately 200 amperes.

[0036] In response to receiving a braking event command signal from an actuator controller 201a and 201b integrated into one of the respective enhanced intelligent brake actuator assemblies 203a and 203b, each actuator driver circuit is configured to output a high-frequency, switched, high-power signal to a respective electromechanical actuator (e.g., a motor). For example, a first actuator controller 201a integrated into a first enhanced intelligent brake actuator assembly 203a may output a first braking event data command signal to the first actuator driver circuit 202a integrated into the first enhanced intelligent brake actuator assembly 203a. The first actuator controller 201a may also output a second braking event data command signal to a second actuator driver circuit 202b integrated into a first enhanced brake actuator assembly 205a.In response to receiving the data command signals, the first actuator driver circuit 202a and the second actuator driver circuit 202b, respectively, may convert the continuous high-power current signal output by the first power source 204a into a high-frequency switched high-current signal, which then drives an electronically controlled actuator (e.g., motor, e-brake caliper) included in the respective brake system 118a and 118b.

[0037] In at least one embodiment, the high-frequency switched high-current signal is generated by a pulse width modulation (PWM) circuit integrated into the actuator driver circuitry 202a and 202b integrated into a respective enhanced intelligent brake actuator assembly 203a and 203b and respective enhanced brake actuator assembly 205a and 205b, respectively. The high-frequency switched high-current signal may have a frequency in the range of about 15 kilohertz (kHz) to about 65 kHz and may have a current value of about 0 A to about 200 A. The high-frequency switched high-current signal may drive a motor that adjusts an E-brake caliper to apply braking force to a respective wheel 112a / 112b and 114a / 114b.Although only the first portion of the BBW system 102 controlled by the first improved intelligent brake actuator assembly 203a has been described, it should be understood that the second portion of the BBW system 102 controlled by the second improved intelligent brake actuator assembly 203b may operate in a similar manner as discussed herein.

[0038] In at least one embodiment, an isolation module 206 is connected between the first and second power sources 204a and 204b and the remaining electrical system of the BBW system 102. The isolation module 206 is configured to receive constant high-power signals generated by the first and second power sources 204a and 204b. Based on the constant high-power signals, the isolation module 206 generates a plurality of individual input signals that are provided to the actuator driver circuits integrated into the enhanced intelligent brake actuator assemblies 203a and 203a and the enhanced brake actuator assemblies 205a and 205b.

[0039] For example, the isolation module 206 outputs first and second constant high-voltage power signals to each actuator driver circuit integrated into a respective brake assembly 118a-118d, as described in detail herein. The isolation module 206 also outputs first and second low-voltage signals that power the first and second actuator controllers 202a and 202b integrated into the respective enhanced smart brake actuator assemblies 203a and 203b. In at least one embodiment, the first and second enhanced smart brake actuators 203a and 203b are in electrical communication with the isolation module 206. In this manner, the first and second enhanced smart brake actuators 203a and 203b can receive various diagnostic information, including, but not limited to, short-circuit events, open-circuit events, and overvoltage events.

[0040] As mentioned above, the isolation module 206 may also be configured to isolate circuit faults on a signal line loop (SLC) and be capable of limiting the number of modules or detectors that may be disabled by a circuit fault on the SLC loop.

[0041] According to one embodiment, when a circuit fault, such as a wire-to-wire short, occurs, the isolation module 206 may automatically create an open (disconnect) in the SLC loop to isolate the enhanced intelligent brake actuator assemblies 203a and 203b and the enhanced brake actuator assemblies 205a and 205b from a circuit fault condition. Additionally, when a power source fault occurs, the isolation module 206 may disconnect the faulty power source 204a or 204b from the brake systems 118a-118d while maintaining the other normally operating power source(s). In this way, the BBW system 102, according to one embodiment, provides at least one fault-tolerant feature. When the circuit fault condition is resolved, the isolation module 206 may automatically reconnect the isolated portion of the SLC loop, e.g., by connecting the isolated portion of the SLC loop to the enhanced intelligent brake actuator assemblies 203a and 203b. B. reconnect the brake systems 118a-118d to the power sources 204a or 204b.

[0042] With reference now to Fig. 3B illustrates a BBW system 102 based on a full-control topology according to one embodiment. The full-control topology of Fig. 3B operates similarly to the method described herein with reference to Fig. 3A described split-control topology. However, the full-control topology differs from Fig. 3B in that each enhanced intelligent brake actuator assembly 203a and 203b is in signal communication with each enhanced brake actuator assembly 205a and 205b. In this way, each of the enhanced brake actuator assemblies 205a and 205b can be disabled and / or overridden by one of the enhanced intelligent brake actuator assemblies 203a and 203b if an enhanced brake actuator assembly 205a and 205b generates unexpected or incorrect data. Accordingly, the full-control BBW topology can provide additional fault-tolerance functionality.

[0043] According to at least one embodiment, the enhanced smart brake actuator assemblies 203a and 203b are configured to selectively operate in a split-topology mode and a full-topology mode based on monitored data. The monitored data includes, but is not limited to, diagnostic results obtained in response to self-diagnostic operations performed by the actuator controllers 202a and 202b integrated with the respective enhanced smart brake actuator assemblies 203a and 203b. For example, when operating in split-topology mode, the first enhanced smart brake actuator assembly 203a controls the first enhanced brake actuator assembly 205a, while the second enhanced smart brake actuator assembly 203b controls the second enhanced brake actuator assembly 205b.

[0044] However, during operation in full topology mode, either the first enhanced intelligent brake actuator assembly 203a or the second enhanced intelligent brake actuator assembly 203b controls both the first enhanced intelligent brake actuator assembly 205a and the second enhanced intelligent brake actuator assembly 205b. That is, during operation in full topology mode, either the first enhanced intelligent brake actuator assembly 203a or the second enhanced intelligent brake actuator assembly 203b is capable of controlling each enhanced brake actuator assembly 205a and 205b.

[0045] As mentioned above, the enhanced smart brake actuator assemblies 203a and 203b may transition to full topology mode based on diagnostic results obtained in response to performing a self-diagnostic test. For example, the first enhanced smart brake actuator assembly 203a may perform a first self-diagnostic operation and transmit first diagnostic results to the second enhanced smart brake actuator assembly 203b. Similarly, the second enhanced smart brake actuator assembly 203b may perform its own second self-diagnostic operation and may transmit second diagnostic results to the first enhanced smart brake actuator assembly 203a. A full topology mode may be initiated if the first diagnostic results and / or the second diagnostic results indicate a fault.For example, if the second diagnostic results provided by the second enhanced intelligent brake actuator assembly 203b indicate a fault, the first enhanced intelligent brake actuator assembly 203a may command the second enhanced intelligent brake actuator assembly 203b to enter a standby mode or an offline mode, invoke full topology mode, and in turn control all enhanced brake actuator assemblies 205a and 205b included in the BBW system 102. In this way, if the second enhanced intelligent brake actuator assembly 203b contains a fault, the BBW system 102 may still be fully actuated by the first enhanced intelligent brake actuator assembly 203a, thereby providing a fault tolerance feature.

[0046] With reference to Fig.4 shows a flowchart of a method for controlling a fault-tolerant BBW system 102 according to one embodiment. The method begins at operation 400, and at operation 402, sensor data is output to a first enhanced smart brake actuator assembly 203a and a second enhanced smart brake actuator assembly 203b. The sensor data may be output from various sensors installed on the vehicle, including, but not limited to, wheel sensors 122a-122b, brake pedal sensors 126-128, and / or object detection sensor(s) 129. At operation 404, a determination is made as to whether the first enhanced smart brake actuator assembly 203a and / or the second enhanced smart brake actuator assembly 203b detects a braking event. The braking event is based on the sensor data described herein. If no braking event is detected, the method returns to operation 402 and continues monitoring the sensor data.

[0047] However, when at least one of the enhanced intelligent brake actuator assemblies 203a / 203b detects a braking event, the first enhanced intelligent brake actuator assembly 203a and the second enhanced intelligent brake actuator assembly 203b communicate with each other to compare their respective detected braking event data at operation 406. For example, a first enhanced intelligent brake actuator assembly 203a may detect a first braking event and may request confirmation that the second enhanced intelligent brake actuator assembly 203b has detected the same or a similar braking event.If the braking event data monitored and generated by the first enhanced intelligent brake actuator assembly 203a matches or substantially matches the braking event data monitored and generated by the second enhanced intelligent brake actuator assembly 203b, the method proceeds to operation 408, wherein a first actuator controller 201a integrated with a first enhanced intelligent brake actuator assembly 203a controls the first enhanced intelligent brake actuator assembly 203a and a first enhanced brake actuator assembly 205a. Similarly, the second actuator controller 201b integrated with a second enhanced intelligent brake actuator assembly 203b controls the second enhanced intelligent brake actuator assembly 203b and a second enhanced brake actuator assembly 205a.In this manner, two separate and individual command signals are output from the first enhanced intelligent brake actuator assembly 203a and the second enhanced intelligent brake actuator assembly 203b. At operation 410, a first electromechanical actuator (e.g., motor, e-caliper) adjusts a first braking torque applied to the first wheel 112a, and a second electromechanical actuator adjusts a second braking torque applied to the second wheel 112b. In this manner, the vehicle may be decelerated or stopped according to the braking event detected by the first and second enhanced intelligent brake actuator assemblies 203a and 203b, and the method ends at 412.

[0048] Referring to operation 406, a scenario may occur where the braking event data monitored and generated by the first enhanced intelligent brake actuator assembly 203a does not match or substantially match the braking event data monitored and generated by the second enhanced intelligent brake actuator assembly 203b. In this case, the method proceeds to operation 414, wherein one of the first enhanced intelligent brake actuator assembly 203a or the second enhanced intelligent brake actuator assembly 203b issues a data command signal to all braking systems 118a-118d. Accordingly, at operation 416, the actuator driver circuits (e.g.,202a) integrated with the normally operating enhanced intelligent brake actuator assembly 203a, and the faulty enhanced intelligent brake actuator assembly 203b drive the associated electromechanical actuator based on the data signal output from a single enhanced intelligent brake actuator assembly (i.e., the normally operating enhanced intelligent brake actuator assembly 203a). This fault-tolerant feature maintains operation of the vehicle braking systems 118a-118d in the event that an enhanced intelligent brake actuator assembly 203a and 203b and / or a portion of the BBW system 102 (including sensors communicating with a particular enhanced intelligent brake actuator assembly) associated with a particular enhanced intelligent brake actuator assembly 203a and 203b experiences a fault.At operation 418, the first electromechanical actuator adjusts a first braking torque applied to the first wheel 112a, and the second electromechanical actuator adjusts a second braking torque applied to the second wheel 112b, and the method ends at operation 412. In this manner, all electromechanical actuators may be controlled in response to a detected braking event, even if an enhanced intelligent brake actuator assembly 203a or 203b is not operating according to expected conditions.

[0049] As discussed in detail herein, various embodiments provide a BBW system including a data interface connecting electronic brake system controllers and enhanced intelligent brake actuators. According to one embodiment, a first enhanced intelligent brake actuator assembly included in a first braking system is controlled by a first actuator controller, while a second enhanced intelligent brake actuator assembly included in a second braking system is controlled by a second actuator controller. Each actuator controller can output low-voltage data command signals to a respective actuator driver circuit (e.g., power circuit) via a communication bus, such as FlexRay™, Ethernet, and a low-voltage message-based interface, e.g., a CAN bus.Accordingly, a flexible BBW system is envisaged that allows flexible design choices, wire length reduction, and flexible braking algorithm implementation while still employing fault tolerance in the system.

[0050] As used herein, the term "module" or "unit" refers to an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), an electronic circuit, an electronic computer processor (shared or dedicated, or group), and a memory executing one or more software or firmware programs, combinational logic circuitry, and / or other suitable components that provide the described functionality. When implemented in software, a module in memory may be embodied as a non-transitory computer-readable storage medium that can be read by processing circuitry and stores instructions that are executed by the processing circuitry to perform a method.

Claims

[1] Vehicle (100) with a fault-tolerant electronic brake-by-wire (BBW) system (102), the vehicle (100) comprising: a plurality of braking systems (118a, 118b, 118c, 118d) configured to control the braking of a respective wheel (112a, 112b, 114a, 114b) of the vehicle (100), the plurality of braking systems (118a, 118b, 118c, 118d) comprising: a first braking system (118b) integrated into a first improved brake actuator assembly (205a) having a first electronic actuator driver circuit (202b) in signal communication with a first electromechanical actuator (120b) configured to adjust a braking force applied to a first wheel (112b) of the vehicle (100); and a second braking system (118a) integrated into a first improved intelligent brake actuator assembly (203a) having a first actuator controller (201a) in signal communication with a second electronic actuator driver circuit (202a), the second electronic actuator driver circuit (202a) being in signal communication with a second electromechanical actuator (120a) configured to adjust a braking force applied to a second wheel (112a) of the vehicle (100); characterized by a third brake system (118d) including a second improved brake actuator assembly (205b), and a fourth brake system (118c) including a second improved intelligent brake actuator assembly (203b), wherein the first improved intelligent brake actuator assembly (203a) is in signal communication with the first improved brake actuator assembly (205a) and the second improved intelligent brake actuator assembly (203b), and wherein the second improved intelligent brake actuator assembly (203b) is in signal communication with the second improved brake actuator assembly (205b) and the first improved intelligent brake actuator assembly (203a). [2] The vehicle (100) of claim 1, wherein the first and second electronic actuator drive circuits (202a, 202b) each comprise a power circuit configured to output a high frequency switched high power current drive signal that drives the first and second electromechanical actuators (12a, 120b), respectively. [3] The vehicle (100) of claim 2, wherein the first actuator controller (201a) is in electrical communication with at least one sensor (126-128) to detect a braking request and is configured to output a low voltage command signal commanding each power circuit to output the high frequency switched high power current drive signal in response to the braking request. [4] The vehicle (100) of claim 1, wherein the first and second actuator controls (201a, 201b) generate operating data based on at least one torque force applied to a respective wheel (112a, 112b, 114a, 114b) of the vehicle (100) and the wheel speed of the wheel (112a, 112b, 114a, 114b) coupled to the respective braking system (118a, 118b, 118c, 118d) including the first and second actuator controls (201a, 201b). [5] The vehicle (100) of claim 4, wherein at least one enhanced intelligent brake actuator assembly (205a, 205) diagnoses the operation of at least one of the first and second brake systems (118a, 118b) based on the operating data. [6] The vehicle (100) of claim 5, wherein the first improved brake actuator assembly (205a) controls the braking force of the first wheel (112b) located on a passenger side of the vehicle (100), and the first improved intelligent brake actuator assembly (203a) controls the braking force of the second wheel (112a) located on the driver side of the vehicle (100), and wherein the second improved brake actuator assembly (205a) controls the braking force of a third wheel (114a) located on the driver side of the vehicle (100), and the second improved intelligent brake actuator assembly (203a) controls the braking force of a fourth wheel (114b) located on the passenger side of the vehicle (100). [7] The vehicle (100) of claim 6, wherein the first improved intelligent brake actuator assembly (205a) is in signal communication with the second improved intelligent brake actuator assembly (203b).

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