Braking system and control method for a braking system

Abstract

The present invention relates to a brake system and a control method of a brake system. A vehicle brake system is configured to mix a brake request signal corresponding to a brake request level with a variable frequency and a variable amplitude (e.g., torque fluctuation) when generating a signal for controlling a brake. The brake system includes one or more brakes that apply a brake to one or more wheels, a memory, and a processor that mixes a brake request signal corresponding to a brake request level with a variable frequency and a variable amplitude to generate a signal for controlling the one or more brakes; the variable frequency is retrieved from one or more predetermined frequencies stored in the memory, and the variable amplitude is calculated based on the brake request level.

Description

Technical Field

[0001] This invention generally relates to an apparatus and method for controlling a vehicle. More specifically, some embodiments of the invention relate to a braking system for a vehicle and a method for controlling the braking system. Background Technology

[0002] An electromechanical brake (EMB) is a braking assembly that operates using electrical energy. For example, an EMB system typically provides braking to a vehicle by using an electric motor that selectively applies power in response to signals from an electronic control unit (ECU) or sensed pressure on a brake input component. Typically, an EMB system may include a rotor, a brake caliper, and brake pads located on opposite sides of the rotor. The brake caliper is slidably supported on a pin fixed to an anchor, which is secured to a non-rotatable component of the vehicle. The brake caliper includes one or more piston cylinders, each housing a piston movable along a piston shaft during brake activation and brake activation release. The brake pads are connected to one or more electric pistons to move between a non-braking position and a braking position where the brake pads move into frictional engagement with opposite braking surfaces of the rotor. For example, when the vehicle operator depresses the brake pedal, an actuator can move a piston to contact one brake pad, then move that brake pad to contact one side of the rotor, while simultaneously moving another opposite brake pad to contact the opposite side of the rotor.

[0003] As a non-limiting example, this EMB system provides the required braking in a significantly shorter time than that provided by a conventional hydraulic braking system, and allows selective control of each wheel of the vehicle or other selectively movable components, thereby improving the effectiveness of many strategies, such as those commonly referred to as slip prevention or lock-up prevention braking strategies or integrated vehicle dynamics strategies.

[0004] The following description of the embodiments takes into account these and other general considerations. Furthermore, while relatively specific problems are discussed, it should be understood that the embodiments are not limited to solving the specific problems identified in the context. Summary of the Invention

[0005] The features and advantages of the invention will be more readily understood and apparent from the following detailed description, which is read in conjunction with the accompanying drawings and the claims.

[0006] Various embodiments of the present invention can provide a braking system configured to, when a signal for controlling the brakes is generated, mix a brake request signal corresponding to the level of the braking request with a variable frequency and variable amplitude (e.g., torque ripple). Therefore, the effect of friction, which directly affects clamping accuracy, can be reduced. Furthermore, the torque ripple added to the brake request signal not only improves the vehicle's braking performance characteristics but also improves brake clamping accuracy. In addition, the brakes can be precisely controlled without the need for a force feedback sensor, thus achieving the vehicle clamping force accuracy target without a force feedback sensor.

[0007] According to some embodiments of the present invention, a vehicle braking system may include: one or more brakes for applying braking to one or more wheels, a memory, and a processor for mixing a braking request signal corresponding to the level of the braking request with a variable frequency and a variable amplitude to generate a signal for controlling one or more brakes; the variable frequency may be retrieved from one or more predetermined frequencies stored in the memory, and the variable amplitude may be calculated based on the level of the braking request.

[0008] The memory can store more than one predetermined frequency of torque ripple. The processor can receive a braking request signal corresponding to the level of braking request, calculate the amplitude of the torque ripple based on the level of braking request, retrieve the frequency of the torque ripple from the memory, and add a torque ripple signal having the calculated amplitude of the torque ripple and the retrieved frequency of the torque ripple to the braking request signal to generate a signal for controlling more than one brake.

[0009] Torque fluctuations can include periodic vibrational motion.

[0010] The processor can count the time for executing torque fluctuations and add a torque fluctuation signal to a braking request signal during the counted time for executing the torque fluctuations.

[0011] The processor can, in response to detecting a decrease in the level of the braking request, begin counting the time of the torque fluctuation.

[0012] The processor can reset the time of the counted execution torque fluctuations to a preset value in response to an increase in the detected braking request level.

[0013] The processor can, in response to a detected decrease in the level of the braking request, add a torque ripple signal having a calculated amplitude of the torque ripple and a retrieved frequency of the torque ripple to the braking request signal to generate a signal for controlling more than one brake.

[0014] The amplitude of torque fluctuations can be calculated in a manner proportional to the braking request.

[0015] The torque fluctuations stored in the memory can have one or more predetermined frequencies ranging from 20 Hz to 50 Hz.

[0016] Signals used to control one or more brakes may include signals that control the torque generated by one or more brakes.

[0017] The processor is configured to generate torque ripple signals using the following equation:

[0018] Torque_Tickle=Torque_Tickle_Amplitude*sin(2π*Torque_Tickle_Frequency*Timer_Counter)

[0019] In the equation, Torque_Tickle is the torque ripple that should be added to the brake request signal, Torque_Tickle_Amplitude is the calculated amplitude of the torque ripple, Torque_Tickle_Frequency is the frequency of the retrieved torque ripple, and Timer_Counter is the time for counting the executed torque ripple.

[0020] According to a specific embodiment of the present invention, a method for controlling a vehicle braking system may include the following steps: receiving a braking request signal corresponding to a braking request level; retrieving a variable frequency from one or more predetermined frequencies stored in a memory, the variable frequency being mixed with the braking request signal corresponding to the braking request level; calculating a variable amplitude based on the braking request level, the variable amplitude being mixed with the braking request signal corresponding to the braking request level; and mixing the braking request signal corresponding to the braking request level with the retrieved variable frequency and the calculated variable amplitude to generate a signal for controlling one or more brakes configured to apply braking to one or more wheels.

[0021] The memory can store more than one predetermined frequency of torque fluctuations. The step of calculating the variable amplitude may include the following steps: calculating the amplitude of the torque fluctuation based on the level of the braking request; the step of retrieving the variable frequency may include the following steps: retrieving the frequency of the torque fluctuation from more than one predetermined frequency of torque fluctuations stored in the memory; the step of mixing the braking request signal with the retrieved variable frequency and the calculated variable amplitude includes the following steps: adding the torque fluctuation signal having the calculated amplitude of the torque fluctuation and the retrieved frequency of the torque fluctuation to the braking request signal to generate a signal for controlling more than one brake.

[0022] Torque fluctuations can include periodic vibrational motion.

[0023] The method for controlling a vehicle braking system may further include the steps of: counting the time of the torque fluctuations and adding a torque fluctuation signal to a braking request signal during the counted time of the torque fluctuations.

[0024] The method for controlling a vehicle braking system may further include the following steps: in response to detecting a decrease in the level of a braking request, starting to count the time of the torque fluctuation.

[0025] The method for controlling the braking system of a vehicle may also include the following steps: in response to an increase in the level of detected braking request, resetting the time for executing torque fluctuations to a preset value.

[0026] The amplitude of torque fluctuations can be calculated in a manner proportional to the braking request.

[0027] The torque fluctuations stored in the memory can have one or more predetermined frequencies ranging from 20 Hz to 50 Hz.

[0028] The control method for the braking system may also include the following steps: generating a torque ripple signal using the following equation:

[0029] Torque_Tickle=Torque_Tickle_Amplitude*sin(2π*Torque_Tickle_Frequency*Timer_Counter)

[0030] In the equation, Torque_Tickle is the torque ripple to be added to the brake request signal, Torque_Tickle_Amplitude is the calculated amplitude of the torque ripple, Torque_Tickle_Frequency is the frequency of the retrieved torque ripple, and Timer_Counter is the time for counting the executed torque ripple.

[0031] This summary is provided to present the selection of concepts described in detail below in a simplified form. This summary is not intended to identify essential or necessary features of the claimed inventive subject matter, nor is it intended to limit the scope of the claimed inventive subject matter. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of a vehicle including a braking system according to an embodiment of the present invention.

[0033] Figure 2 This is a block diagram of the controller of a braking system according to an embodiment of the present invention.

[0034] Figure 3 This is a flowchart illustrating a method for controlling a braking system according to an embodiment of the present invention.

[0035] Figure 4 This is a flowchart illustrating the steps of counting the time used to perform torque fluctuations in an embodiment of the present invention.

[0036] Figure 5 This is a graph illustrating an example of a braking request signal and a signal in which torque fluctuations are mixed with the braking request signal, according to an embodiment of the present invention.

[0037] Figure 6 It is a graph used to show the hysteresis loops of brake cycles with and without torque fluctuations.

[0038] Figure 7 This is a cross-sectional view of a brake according to an embodiment of the present invention. Detailed Implementation

[0039] Throughout this specification, the same reference numerals refer to the same constituent elements. This specification does not describe all elements of the embodiments; content that is general in the technical field to which the disclosed invention pertains or that is repeated between embodiments will be omitted. The terms "part," "module," "component," and "block" used in this specification may be implemented in software or hardware, or multiple "parts," "modules," "components," and "blocks" may be implemented as a single constituent element, or one "part," "module," "component," and "block" may include multiple constituent elements.

[0040] Throughout the specification, when referring to a part being "connected" to another part, it includes not only direct connections but also indirect connections, including connections via wireless communication networks.

[0041] Furthermore, when a part is described as "including" a certain constituent element, it indicates that other constituent elements may also be included, rather than excluding other constituent elements, unless there is a statement to the contrary.

[0042] Throughout the instruction manual, when it is stated that a component is located "on" another component, it includes not only the case where one component is connected to another component, but also the case where there is another component between the two components.

[0043] The terms "first" and "second" are used to distinguish one constituent element from other constituent elements, and the constituent elements are not limited to the terms mentioned above.

[0044] Unless there are obvious exceptions in the context, the singular expression includes the plural expression.

[0045] In each step, the identification symbols are used for ease of explanation, not to indicate the order of the steps. If no obvious specific order is written in the context, the steps may be performed in an order different from the written order.

[0046] In the following detailed description, specific embodiments that form part of and enable the implementation of the invention are illustrated with reference to the accompanying drawings, which are provided by way of example. These embodiments are described in sufficient detail to enable those skilled in the art to implement the invention. It should be understood that other embodiments may be used and structural, logical, and electrical changes may be made without departing from the spirit and scope of the invention. Therefore, the following detailed description should not be construed as limiting, and the scope of the invention is defined only by the appended claims and their equivalents. Similar reference numerals in the drawings indicate similar constituent elements, which should be clearly apparent from the context of their use.

[0047] The working principle and embodiments of the disclosed invention will now be described with reference to the accompanying drawings.

[0048] Figure 1 This is a schematic diagram of a vehicle including a braking system according to an embodiment of the present invention.

[0049] Reference Figure 1 The vehicle 100 may include multiple wheels. For example, the wheels of the vehicle 100 may include a left front (FL) wheel 101, a right front (FR) wheel 102, a left rear (RL) wheel 103, and a right rear (RR) wheel 104. The braking system may include a braking assembly 110, a controller 130, and one or more sensors 150.

[0050] Braking assembly 110 may include multiple brakes 111, 112, 113, and 114 operably coupled to four wheels (i.e., left front wheel 101, right front wheel 102, left rear wheel 103, and right rear wheel 104). Brakes 111, 112, 113, and 114 are configured to apply individual braking forces to the left front wheel 101, right front wheel 102, left rear wheel 103, and right rear wheel 104, respectively. For example, braking can be achieved by forcing the brake pads of the brakes to the vehicle wheel rims. Brakes 111, 112, 113, and 114 can be independently activated by controller 130. An exemplary embodiment of brakes 111, 112, 113, and 114 is illustrated in U.S. Patent Application Publication No. 2013 / 0314222. Figure 7 The aforementioned U.S. Patent Application Publication No. 2013 / 0314222 is assigned to the assignee of this invention and is thereby incorporated herein by reference in its entirety. However, any type of brake can be applied to this invention.

[0051] The action of the braking assembly 110 may be accompanied by the vehicle operator pressing the brake pedal 120, which is sensed by the brake pedal sensor 141. The brake pedal sensor 141 monitors the position, force and / or state of the brake pedal 120 and provides the controller 130 with a brake request signal (also known as the driver's braking intention) indicating the level of the brake request as requested, such as the braking torque.

[0052] Additionally, the controller 130 can generate a braking request signal for controlling the braking assembly 110 based on control algorithms, software, or instructions stored in the memory. These control algorithms, software, or instructions are not limited to, for example, autonomous driving software for automatically controlling a vehicle or assisting a vehicle operator, advanced driver assistance systems (ADAS), traction slip control, anti-lock braking control, electronic stability control, and any other algorithm or computer-implemented system.

[0053] Various sensors 150 can be associated with controller 130 and can be used individually or in various combinations, depending on conditions. Sensors may include any combination of components, devices, modules, systems, etc., that can be used to measure wheel speed, wheel acceleration, vehicle speed, vehicle acceleration, friction braking torque, regenerative braking torque, tire pressure, vehicle mass, yaw, yaw rate, steering angle, road gradient, weather conditions, or any other vehicle operating parameters for controlling vehicle 100. One or more sensors may be implemented as hardware, software, firmware, or a combination thereof, and may be connected to controller 130 electronically, via other electronic components such as other devices, modules, and systems, via vehicle communication buses or networks, or via some other communication electronics. Other sensors may be used to supplement or verify the decisions of other sensors. For example, some sensors may be used to examine images or radar signals, and vice versa.

[0054] The controller 130 can be programmed to perform various functions and control various outputs in response to information received from multiple sensors. The controller 130 is electrically connected to various elements of the vehicle 100, including, but not limited to, the braking assembly 110, such as brakes 111, 112, 113, 114, sensors 150, and a memory 135. The controller 130 can be configured to receive various input signals, not limited to signals from multiple sensors disposed in the vehicle 100. During braking action of the braking assembly 110, the controller 130 can continuously receive signals from the sensors 150, or it can receive telemetry information from the sensors 150 after a braking event occurs. The controller 130 is configured to output control signals to the braking assembly 110 to control the brakes 111, 112, 113, and 114.

[0055] Controller 130 may be, but is not limited to, devices and / or microprocessors or computers using technologies such as mechanical, hydraulic, pneumatic, and electronic systems, which monitor and physically change the operating conditions of a given dynamic system. In one example, controller 130 may include a programmable logic controller (PLC) of the Allen-Bradley brand. Controller 130 may include more than one processor (e.g., Figure 2 (210), used to perform calculations to process inputs and / or outputs. Controller 130 may include memory (e.g., Figure 2 The controller 130 (240) is used to store preset or predetermined values ​​for controlling the braking system and values ​​processed by the processor, or to store the results of previous processing. The controller 130 can also be configured to accept inputs and outputs from multiple input and output devices used for receiving or sending values. Such devices include other computers, keyboards, mice, visual displays, industrial equipment, and systems or machines of various types and sizes. For example, the controller 130 can control a network or network interface to perform various network communications upon request. The network interface can be characterized as part of the controller 130 or detached from and remotely connected to the controller 130. The controller 130 can be a single physical computing device with functions similar to a desktop or laptop computer, or it can consist of multiple devices of the same type, such as a group of servers acting as a device in a networked cluster or a heterogeneous combination of different computing devices acting as a controller and linked together by a communication network. The communication network connected to the controller 130 can also be connected to a wider network, such as the Internet. Therefore, the controller 130 can include more than one physical processor or other computing device or circuitry, and may also include any suitable type of memory. The controller 130 can also be a virtual computing platform with an unknown or variable number of physical processors and memory or memory devices. Therefore, controller 130 can operate as a single controller, physically located within a geographical area, or physically distributed across a wide range of locations as multiple processors linked together via a communication network. Multiple controllers or computing devices can be configured to communicate with each other or with other devices via wired or wireless communication links to form a network. Network communication can occur through various controllers operating as network machines such as switches, routers, firewalls, or other network devices or interfaces, before passing through larger computer networks such as the Internet. Communication can also be transmitted over a network, such as wireless data transmission via electromagnetic waves through transmission lines or free space. This communication includes using WiFi or other wireless local area networks (WLANs) or cellular transmitters / receivers to transmit data.

[0056] Memory 135 stores characteristic data, information, and values ​​(parameters, curves, maps, patterns, tables, and / or critical values), such as brake characteristic parameters used to control brakes 111, 112, 113, and 114 respectively. Brake characteristic parameters may include parameters related to the braking force and / or braking time used to control brakes 111, 112, 113, and 114 respectively. For example, initial parameters are determined based on the results of various parameters tested in a hypothetical test environment and stored in memory 135. Controller 130 can change the initial parameters through correction actions. Figure 1 As shown, memory 135 can be a separate memory associated with controller 130, or as... Figure 2 As shown, it can be integrated into the controller 130.

[0057] Figure 2 This is a block diagram of the controller of a braking system according to an embodiment of the present invention. Figure 3 This is a flowchart illustrating a method for controlling a braking system according to an embodiment of the present invention.

[0058] Figure 1 The controller 130 may include a processor 210 and a memory 240. However, the memory 240 may not be included in the controller 130. For example, Figure 2 The memory 240 can be implemented as Figure 1 The memory 135 is a separate memory associated with the controller 130. Alternatively, the memory 240 may be integrated within the processor 210.

[0059] Figure 2 The structure and operation of the memory 240 can be related to Figure 1 The memory 135 has the same or similar structure and operation. For Figure 2 The same description will be omitted for memory 240.

[0060] like Figure 1 As shown, controller 130 may be a central controller, but the invention is not limited thereto. Alternatively, controller 130 may be implemented as multiple controllers having a storage medium and a suitable number of programmable memories, which can store and execute more than one algorithm or method to control brakes 111, 112, 113, 114, each brake 111, 112, 113, 114 may include a corresponding controller, or be operatively connected to a corresponding controller for controlling the corresponding brake. For example, each controller may be a controller located in an EMB unit located at a corner of vehicle 100. However, according to the invention, more than one controller may be configured in any suitable location of vehicle 100 and may be implemented in any suitable manner.

[0061] Processor 210 may be a computer processor in which data and signal processing logic and control are included in one or more integrated circuits. Processor 210 may include arithmetic, logic, and control circuitry required to perform the functions of a central processing unit (CPU). Processor 210 includes a microprocessor with a large-scale integrated circuit (LSI), which includes, but is not limited to, ROM storing, control programs such as those for controlling a braking system and various constants. Processor 210 may include: a CPU for reading the control program from the ROM to perform desired actions; and RAM for temporarily storing various data related to the actions performed in the CPU and allowing the CPU to read the data stored therein. Processor 210 may include: a clock generator for generating clock pulses in response to the execution of various actions in processor 210; and input-output devices for controlling various input-output signals entering and exiting processor 210.

[0062] In step 302, processor 210 receives a brake request signal IN. The brake request signal IN is generated in a manner corresponding to the level of brake request. The brake request signal IN can represent the braking torque requested by the driver. Specifically, the brake request signal IN has a magnitude corresponding to the level of braking force input by the driver, which can be determined by… Figure 1 The brake pedal sensor 141 senses the brake request signal IN. Other techniques and methods can be used to generate the brake request signal IN. For example, the brake request signal IN corresponding to the level of the brake request can be generated according to driver assistance and automatic driving algorithms or software instructions for controlling vehicle 100 and / or braking components 110, such as automatic driving software for automatically controlling the vehicle or assisting the vehicle operator, advanced driver assistance systems (ADAS), traction control, anti-lock braking control, electronic stability control, and any other algorithm or computer implementation system.

[0063] Processor 210 counts the time spent executing torque fluctuations (step 305). Torque fluctuations can be periodic vibrational motions. For example, torque fluctuations are continuous, rapid, and slight oscillations. Torque fluctuations can have variable amplitude and variable frequency, as will be described in detail later.

[0064] A detailed exemplary embodiment of step 305 is described in Figure 4 The explanation is provided below. Figure 4 This is a flowchart illustrating the steps of counting the time used to perform torque fluctuations according to an embodiment of the present invention. Figure 4In an exemplary embodiment, processor 210 detects an increase and / or decrease in the level of the brake request signal IN (step 402). When processor 210 detects a decrease in the level of the brake request signal IN (step 405), processor 210 begins counting the duration of the torque fluctuations (step 407). The duration of the torque fluctuations can be counted until the level of the brake request signal IN stops decreasing (e.g., the level of the brake request increases or remains unchanged). Next, when an increase in the level of the brake request is detected (step 410), processor 210 resets the counted duration of the torque fluctuations to a preset value, such as, but not limited to, zero (0) (step 412).

[0065] Therefore, according to a partial exemplary embodiment of the invention, torque fluctuations are mixed with the commanded braking torque only when the level of the braking request decreases, but the braking torque is applied to the wheel, such as the rotor, without torque fluctuations during periods when the level of the braking request increases.

[0066] Back Figure 2 and Figure 3 The amplitude calculator 220 of processor 210 calculates the variable amplitude of the torque ripple signal to be mixed with the braking request signal IN (step 307). The variable amplitude of the torque ripple signal can be calculated based on the level of the braking request. For example, the variable amplitude of the torque ripple signal can be proportional to the level of the braking request. The amplitude of the torque ripple can be calculated according to the following Equation 1.

[0067] Equation 1:

[0068] Torque_Tickle_Amplitude=(Brake_Request)*(Dither_Gain)

[0069] In Equation 1, Torque_Tickle_Amplitude is the amplitude of torque ripple, Brake_Request is the level of braking request, and Dither_Gain is an adjustable parameter (e.g., a parameter predetermined by experimental testing and / or subsequently changed by corrective action).

[0070] The memory 240 is configured to store one or more predetermined or preset frequencies of torque ripple signals. The predetermined or preset frequencies of the torque ripple signals can be adjustable parameters that are predetermined through experimental testing and / or subsequently changed through calibration actions. The predetermined or preset frequencies of the torque ripple signals can be set to 20Hz to 50Hz. A frequency range of 20Hz to 50Hz for the torque ripple signals can improve the accuracy of the braking clamping force in response to braking requests. In step 310, the processor 210 retrieves from the memory 240 a frequency from the predetermined frequencies of the torque ripple signals that should be mixed with the braking request signal IN.

[0071] The brake control signal generator 260 of processor 210 mixes the brake request signal IN with a variable amplitude calculated by the amplitude calculator 220 of processor 210 and a variable frequency retrieved from memory 240 to generate a signal OUT for controlling brakes 111, 112, 113, and 114 (step 312). For example, the signal OUT for controlling brakes 111, 112, 113, and 114 may be a signal for controlling the torque applied to the left front wheel 101, right front wheel 102, left rear wheel 103, and right rear wheel 104 by brakes 111, 112, 113, and 114. The brake control signal generator 260 of processor 210 may add a torque fluctuation signal having the amplitude calculated by the amplitude calculator 220 of processor 210 in step 307 and the frequency retrieved from memory 240 in step 310 to the brake request signal IN. For example, the torque fluctuation signal may be generated using the following equation 2.

[0072] Equation 2:

[0073] Torque_Tickle=Torque_Tickle_Amplitude*sin(2π*Torque_Tickle_Frequency*Timer_Counter

[0074] In Equation 2, Torque_Tickle is the torque ripple to be added to the brake request signal, Torque_Tickle_Amplitude is the amplitude of the torque ripple calculated in step 307, Torque_Tickle_Frequency is the frequency of the torque ripple retrieved in step 310, and Timer_Counter is the time for executing the torque ripple counted in step 305.

[0075] The torque fluctuation signal generated using Equation 2 is added to the brake request signal IN to generate a signal OUT for controlling brakes 111, 112, 113, and 114. For example, the signal OUT for controlling brakes 111, 112, 113, and 114 can represent the signal generated by the motor 710 and gear assembly 720. Figure 7 The actuator 700 generates braking torque. In this case, the signals for controlling brakes 111, 112, 113, and 114 can be generated according to the following equation 3.

[0076] Equation 3:

[0077] Actuator_Command=Commanded_Torque+Torque_Tickle_Amplitude*sin(2π*Torque_Tickle_Frequency*Timer_Counter)

[0078] In Equation 3, Actuator_Command is the torque generated by the actuator of the brake, Commanded_Torque is the clamping force of the command applied to the rotor of the wheel, Torque_Tickle_Amplitude is the amplitude of the torque ripple, Torque_Tickle_Frequency is the frequency of the torque ripple, and Timer_Counter is the time for counting the execution of the torque ripple.

[0079] Here, the Commanded_Torque in Equation 3 can be calculated using the following Equation 4.

[0080] Equation 4:

[0081] Commanded_Torque=Brake_Request / (Gear_Ratio*System_Efficiency)

[0082] In Equation 4, Commanded_Torque is the clamping force of the command, Brake_Request is the level of the braking request, Gear_Ratio is the gear ratio of the brake, and System_Efficiency is the efficiency of the brake's actuator.

[0083] Examples of brake request signals and signals used to control the brakes are as follows: Figure 5 As shown, here, torque fluctuations with variable frequency and amplitude are mixed with the braking request signal. Line 510 represents the braking request signal IN, and line 520 represents the signal OUT used to control brakes 111, 112, 113, and 114. When the braking request signal IN, represented by line 510, is received, the processor 210 mixes the torque fluctuations with variable frequency and amplitude into the braking request signal IN in the manner described above, thereby generating the signal OUT, represented by line 520, used to control brakes 111, 112, 113, and 114. Figure 5 In the example shown, torque fluctuations are mixed with the brake request signal IN only when the brake request level decreases, but torque fluctuations are not mixed with the brake request signal IN during periods when the brake request level increases.

[0084] In step 315, processor 210 outputs the signal OUT generated in step 312 for controlling brakes 111, 112, 113, and 114, such that during the time period of the executed torque fluctuation counted in step 305, controller 130 can control brakes 111, 112, 113, and 114 by using the signal OUT for controlling brakes 111, 112, 113, and 114. Processor 210 can command the actuators 700 of brakes 111, 112, 113, and 114 to generate the braking torque requested by the braking request received in step 302.

[0085] Figure 6 This illustration shows that specific embodiments of the invention, by mixing a brake request signal corresponding to the level of the brake request with a variable frequency and variable amplitude (e.g., torque ripple) to generate a signal for controlling the brake, can reduce system hysteresis and improve the accuracy of brake torque control for the original clamping force request. Line 610 shows the applicable portion of the braking cycle with increasing brake torque. As described above, some embodiments of the invention do not have torque ripple during the increase in the level of the brake request, applying brake torque to a wheel, such as a rotor. Line 620 represents the hysteresis loop of the release portion of a braking cycle with torque ripple, line 630 represents a braking cycle in which torque ripple begins in the middle cycle, and line 640 represents the hysteresis loop of the release portion of a braking cycle without torque ripple. Line 620, representing the hysteresis loop of the release portion of a braking cycle with torque ripple, is closer to line 610, which represents the applicable portion of the braking cycle, than line 640, which represents the hysteresis loop of the release portion of a braking cycle without torque ripple. Therefore, by mixing the torque ripple with the commanded brake torque, hysteresis during brake release can be reduced.

[0086] According to some embodiments of the present invention, by mixing a brake request signal corresponding to the level of the brake request with a variable frequency and a variable amplitude (e.g., torque ripple) when generating a signal for controlling the brakes, the frictional effects that directly affect clamping accuracy can be reduced. Therefore, the torque ripple added to the brake request signal can not only improve the braking performance characteristics of the vehicle but also improve brake clamping accuracy.

[0087] Traditional braking systems require force feedback sensors, which can result in delayed feedback due to the sensor signal. However, according to specific embodiments of the invention, in order to generate a signal for controlling the brakes, a signal of torque fluctuations with variable frequency and amplitude is added to the brake request signal. This allows the braking system to precisely control the brakes without a force feedback sensor, and the vehicle clamping force accuracy target can be met without a force feedback sensor. Since the electronic braking systems of some embodiments of the invention do not require a force feedback sensor, the electronic architecture of the electronic braking system can be simplified, and the manufacturing cost of the vehicle's braking system can be reduced. Furthermore, due to the reduced delay when applying clamping force relative to the clamping force capability, the system reliability and braking performance of the braking control system of specific embodiments of the invention can be improved.

[0088] As will be understood by those skilled in the art, aspects of the present invention can be implemented as a system, method, or computer program product. Therefore, aspects of the present invention can take the form of a completely hardware embodiment, a completely software embodiment (including firmware, resident software, microcode, etc.), or a combination of software and hardware aspects generally referred to herein as "circuit," "module," or "system." Further, aspects of the present invention can take the form of a computer program product implemented in one or more computer-readable media, which implement computer-readable program code. The amplitude calculator 220 and the brake control signal generator 260 can be hardware-based units, software-based units, or a combination of hardware and software. Hardware-based units may include embedded components such as chipsets, dedicated circuits, and one or more memory devices, while software-based units may be linked to a portion of program code or program code including specific program instructions and may be loaded into memory. The amplitude calculator 220 and the brake control signal generator 260 can be designed to implement or perform one or more of the aforementioned specific functions or routines.

[0089] For example, as discussed in more detail above, embodiments of the present invention may include or utilize a dedicated or general-purpose computer, which includes computer hardware such as more than one processor and system memory. Embodiments within the scope of the present invention also include physical and other computer-readable media for transmitting or storing computer-executable instructions and / or data structures. These computer-readable media may be any usable medium accessible through a general-purpose or dedicated computer system. A computer-readable medium storing computer-executable instructions is a computer storage medium (device). A computer-readable medium transmitting computer-executable instructions is a transmission medium. Thus, by way of non-limiting example, embodiments of the present invention may include at least two different types of computer-readable media: a computer storage medium (device) and a transmission medium.

[0090] Computer storage media (devices) include RAM, ROM, EEPROM, CD-ROM, solid-state drives (“SSDs”) (e.g., RAM-based), flash memory, phase-change memory (“PCM”), other types of memory, other optical disc storage, disk storage or other magnetic storage devices or any other media that can be used to store required program code components in the form of computer-executable instructions or data structures and can be accessed by a general-purpose or special-purpose computer.

[0091] Furthermore, upon arrival at various computer system components, program code components in the form of computer-executable instructions or data structures can be automatically sent from the transmission medium to the computer storage medium (device) (or vice versa). For example, computer-executable instructions or data structures received via a network or data link are buffered in the RAM of a network interface module (e.g., a "NIC") and can then eventually be sent to the computer system RAM and / or to the low-volatility computer storage medium (device) within the computer system. RAM may also include solid-state drives (SSD-based or PCIx-based real-time memory tiers, such as FusionIO). Therefore, it should be understood that the computer storage medium (device) may also (or even primarily) include computer system components that utilize the transmission medium.

[0092] Those skilled in the art will understand that this invention can be implemented in network computing environments comprising a wider variety of computer systems, including personal computers, desktop computers, laptop computers, message processors, handheld devices, multiprocessor systems, microprocessor-based or programmable home appliances, network PCs, microcomputers, host computers, mobile phones, PDAs, tablet computers, pagers, routers, switches, and various storage devices. This invention can also be implemented in distributed system environments where both local and remote computer systems linked via a network (via hardwired data links, wireless data links, or a combination of hardwired and wireless data links) perform operations. In a distributed system environment, program modules can reside on both local and remote memory storage devices.

[0093] Embodiments of the present invention can also be implemented in a cloud computing environment. In this description and the appended claims, "cloud computing" is defined as a model that enables rapid provisioning through virtualization and de-provisioning through minimal management effort or service provider interaction, allowing for general and convenient customized network access to a shared pool of correspondingly scaled computing resources (e.g., networks, servers, storage, applications, services). The cloud model can consist of various features (e.g., customized self-service, WAN access, resource pooling, rapid elasticity, measurement services, etc.), service models (e.g., Software as a Service (SaaS), Platform as a Service (PaaS), Infrastructure as a Service (IaaS), and deployment models (e.g., private cloud, community cloud, public cloud, hybrid cloud, etc.). The databases and services described in this invention may be included in the cloud model.

[0094] Furthermore, where appropriate, the functions described herein can be performed by more than one of hardware, software, firmware, digital components, or analog components. For example, more than one application-specific integrated circuit (ASIC) can be programmed to perform more than one of the systems and steps described herein. Specific terms are used in the specification and claims to refer to specific system components. As will be understood by those skilled in the art, components may be referred to by different names. This invention does not imply the distinction between components with different names but the same function.

[0095] The technical terms used herein are for illustrative purposes only and are not intended to limit the invention. As used herein, unless the context clearly indicates otherwise, the singular form (indefinite articles (“a”, “an”) and the definite article (“the”) also include the plural form. It should be understood that the terms “comprising” and / or “including”, when used in this specification, indicate the presence of a specified feature, integer, step, action, element, and / or constituent element, but do not preclude the presence or addition of more than one other feature, integer, step, action, element, constituent element, and / or combination thereof.

[0096] It should be understood that, although exemplary embodiments have been described in detail, various changes, substitutions and alterations may be made herein without departing from the spirit and scope of the application as defined in the appended claims.

[0097] Furthermore, the scope of this application is not intended to be limited to the specific embodiments of the processes, machinery, manufacture, and material composition, components, methods, and steps described in the specification. Those skilled in the art will readily understand from the disclosure that currently existing or to-be-developed processes, machinery, manufacture, material composition, components, methods, or steps that perform substantially the same functions or achieve substantially the same results as the corresponding embodiments described herein can be used, based on embodiments and alternative embodiments. Therefore, the appended claims are intended to include such processes, machinery, manufacture, material composition, components, methods, or steps within the scope of the claims.

Claims

1. A braking system, wherein, include: More than one brake applies braking to more than one wheel. Memory, and The processor mixes a braking request signal corresponding to the level of the braking request with a variable frequency and a variable amplitude to generate a signal for controlling the one or more brakes. The variable frequency is retrieved from one or more predetermined frequencies stored in the memory. The variable amplitude is calculated based on the level of the braking request. The processor, In response to the detection of a decrease in the level of the braking request, the time for the execution torque fluctuation is counted. During the time period of the counted torque fluctuations, a torque fluctuation signal is added to the brake request signal.

2. The braking system according to claim 1, wherein, The memory stores one or more predetermined frequencies of the torque fluctuations; The processor, Receive the braking request signal corresponding to the level of the braking request. The amplitude of the torque fluctuation is calculated based on the level of the braking request. Retrieve the frequency of the torque fluctuation from the memory, and The torque ripple signal, having the calculated amplitude of the torque ripple and the retrieved frequency of the torque ripple, is added to the braking request signal to generate a signal for controlling the one or more brakes.

3. The braking system according to claim 2, wherein, The torque fluctuations include periodic vibrational motions.

4. The braking system according to claim 1, wherein, The processor, In response to an increase in the level of the detected braking request, the time for executing the torque fluctuation is reset to a preset value.

5. The braking system according to claim 2, wherein, The processor, In response to the detection of a decrease in the level of the braking request, a torque ripple signal having a calculated amplitude of the torque ripple and a retrieved frequency of the torque ripple is added to the braking request signal to generate a signal for controlling the one or more brakes.

6. The braking system according to claim 2, wherein, The amplitude of the torque fluctuation is calculated in a manner proportional to the braking request.

7. The braking system according to claim 2, wherein, The torque fluctuations stored in the memory have a predetermined frequency of 20 Hz to 50 Hz.

8. The braking system according to claim 1, wherein, Signals used to control the one or more brakes include signals that control the torque generated by the one or more brakes.

9. The braking system according to claim 2, wherein, The processor is configured to generate the torque ripple signal using the following equation: Torque_Tickle=Torque_Tickle_Amplitude*sin(2π*Torque_Tickle_Frequency *Timer_Counter) In the equation, Torque_Tickle is the torque ripple to be added to the brake request signal, Torque_Tickle_Amplitude is the calculated amplitude of the torque ripple, Torque_Tickle_Frequency is the retrieved frequency of the torque ripple, and Timer_Counter is the counted time for executing the torque ripple.

10. A control method for a braking system, wherein, Includes the following steps: Receive the braking request signal corresponding to the level of braking request; A variable frequency is retrieved from one or more predetermined frequencies stored in the memory, the variable frequency being mixed with the braking request signal corresponding to the level of the braking request; The variable amplitude is calculated based on the level of the braking request, and the variable amplitude is mixed with the braking request signal corresponding to the level of the braking request; as well as The braking request signal corresponding to the level of the braking request is mixed with the retrieved variable frequency and the calculated variable amplitude to generate a signal for controlling one or more brakes configured to apply braking to one or more wheels. It also includes the following steps: In response to the detection of a decrease in the level of the braking request, the time for the execution torque fluctuation is counted. During the time period of the counted torque fluctuations, a torque fluctuation signal is added to the brake request signal.

11. The control method for the braking system according to claim 10, wherein, The memory stores one or more predetermined frequencies of the torque fluctuations; The steps for calculating the variable amplitude include the following steps: calculating the amplitude of the torque fluctuation based on the level of the braking request; The step of retrieving the variable frequency includes the following steps: retrieving the frequency of the torque fluctuation from one or more predetermined frequencies of the torque fluctuation stored in the memory; The step of mixing the brake request signal with the retrieved variable frequency and the calculated variable amplitude includes the following steps: adding a torque fluctuation signal having the calculated amplitude of the torque fluctuation and the retrieved frequency of the torque fluctuation to the brake request signal to generate a signal for controlling the one or more brakes.

12. The control method for the braking system according to claim 11, wherein, The torque fluctuations include periodic vibrational motions.

13. The control method for the braking system according to claim 10, wherein, It also includes the following steps: In response to the detection of an increase in the level of the braking request, the time for executing the torque fluctuation is reset to a preset value.

14. The control method for the braking system according to claim 11, wherein, The amplitude of the torque fluctuation is calculated in a manner proportional to the braking request.

15. The control method for the braking system according to claim 11, wherein, The torque fluctuations stored in the memory have one or more predetermined frequencies ranging from 20 Hz to 50 Hz.

16. The control method for the braking system according to claim 11, wherein, It also includes the following steps: The torque ripple signal is generated using the following equation: Torque_Tickle=Torque_Tickle_Amplitude*sin(2π*Torque_Tickle_Frequency *Timer_Counter) In the equation, Torque_Tickle is the torque ripple to be added to the brake request signal, Torque_Tickle_Amplitude is the calculated amplitude of the torque ripple, Torque_Tickle_Frequency is the retrieved frequency of the torque ripple, and Timer_Counter is the counted time for executing the torque ripple.

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