System and method for clamp force control in electromechanical braking

Abstract

A method for controlling an electromechanical braking (EMB) unit in a vehicle includes: determining a clamping force deviation as the difference between a requested clamping force and an actual clamping force; using a proportional-integral-derivative (PID) control loop and based on the clamping force deviation to determine a command for a brake actuator; determining an operating state of the EMB unit as either a clamping request or a release request; and selectively enabling integral control of the PID control loop based on the operating state of the EMB unit.

Description

Technical Field

[0001] This disclosure relates to braking systems, and more particularly to systems and methods for controlling clamping forces in electromechanical braking (EMB) systems. Background Technology

[0002] Vehicles (such as cars, trucks, SUVs, crossovers, vans, ships, aircraft, all-terrain vehicles, recreational vehicles, or other suitable forms of transport) typically include braking systems, such as hydraulic braking systems, electric braking systems, or electromechanical braking (EMB) systems. These braking systems generally control various aspects of the vehicle's braking, including providing braking assistance to the operator, anti-lock braking system (ABS) activation, traction control, and more.

[0003] In an EMB system, closed-loop control can be performed using a proportional-integral-derivative (PID) control loop in response to upper clamping and release requests. When a clamping force is requested, the EMB system software executes closed-loop control through the PID control loop and outputs motor control torque. For the wheel-end actuators in an EMB system, the system may exhibit high stiffness that changes non-linearly with the actual clamping force. To achieve rapid clamping force tracking, segmented control parameters with relatively large values ​​can be used. These larger segmented control parameters can quickly eliminate steady-state errors and improve steady-state performance.

[0004] However, larger segmented control parameters can also introduce two major problems. First, due to the significant variation in system stiffness between different clamping force levels, the integral control parameters may need to be segmented according to different stiffness regions to quickly eliminate steady-state errors. This results in sluggish anti-saturation for EMB systems as the integral coefficient transitions from a large to a small value, ultimately compromising the stability of the entire control system. While a larger integral coefficient can quickly eliminate steady-state errors, it also introduces system hysteresis. When combined with the inherent hysteresis of integral control, this further exacerbates the response delay, degrades dynamic performance, and severely weakens control effectiveness in high-dynamic scenarios such as anti-lock braking systems (ABS), traction control systems (TCS), and / or vehicle dynamic control (VDC). Analysis of these two aspects reveals that the primary role of the integral coefficient is to eliminate steady-state errors and enhance steady-state clamping force control performance. Summary of the Invention

[0005] This disclosure generally relates to electromechanical braking (EMB) systems for vehicles such as buses and trucks.

[0006] One aspect of the disclosed embodiments includes a method for controlling an electromechanical braking (EMB) unit in a vehicle. The method includes: adjusting the clamping force deviation ( ) is determined to be the requested clamping force ( ) and actual clamping force ( The difference between the clamping force deviations; using a proportional-integral-derivative (PID) control loop and based on the clamping force deviation ( The system determines the command for the brake actuator; determines the operating state of the EMB unit as either a clamping request or a release request; and selectively enables integral control of the PID control loop based on the operating state of the EMB unit.

[0007] One aspect of the disclosed embodiments includes a braking system for a vehicle. The braking system includes an electromechanical braking (EMB) unit and a controller. The EMB unit includes an actuator configured to apply an actual clamping force (…). This slows down the vehicle. The controller is configured to: reduce clamping force deviation ( ) is determined to be the requested clamping force ( ) and the actual clamping force applied by the actuator ( The difference between the clamping force deviations; using a proportional-integral-derivative (PID) controller and based on the clamping force deviation ( The system determines the command for the actuator; determines the operating state of the EMB unit as either a clamping request or a release request; and selectively enables integral control of the PID control loop based on the operating state of the EMB unit.

[0008] These and other aspects of this disclosure are disclosed in the following detailed description of the embodiments, the appended claims and the accompanying drawings. Attached Figure Description

[0009] This disclosure is best understood by reading in conjunction with the accompanying drawings and through the following detailed description. It should be emphasized that, by convention, the various features in the drawings are not drawn to scale. Instead, for clarity, the dimensions of the various features have been arbitrarily enlarged or reduced.

[0010] Figure 1 A schematic block diagram of a braking system in a vehicle according to the principles of this disclosure is shown.

[0011] Figure 2 A schematic block diagram of an electromechanical braking unit based on the principles of this disclosure is shown.

[0012] Figure 3 A schematic block diagram of a motor controller according to the principles of this disclosure is shown.

[0013] Figure 4 A flowchart is shown illustrating the steps for determining the operating state of an electromechanical braking unit in accordance with the principles of this disclosure.

[0014] Figure 5 A flowchart is shown illustrating the first and second conditions for integral control of the proportional-integral-derivative (PID) control loop of the electromechanical braking unit, according to the principles of this disclosure.

[0015] Figure 6 A flowchart is shown illustrating the third condition for integral control of the proportional-integral-derivative (PID) control loop of the electromechanical braking unit, according to the principles of this disclosure.

[0016] Figures 7A to 7G A flowchart is shown, which outlines the steps in a method for controlling an electromechanical braking (EMB) unit in a vehicle according to the principles of this disclosure. Detailed Implementation

[0017] The following discussion pertains to various embodiments of this disclosure. While one or more of these embodiments may be preferred, the disclosed embodiments should not be construed as or otherwise used to limit the scope of this disclosure, including the claims. Furthermore, those skilled in the art will understand that the following description has broad application, and the discussion of any embodiment is intended only as an illustrative discussion of that embodiment and not to imply that the scope of this disclosure, including the claims, is limited to that embodiment.

[0018] As mentioned above, vehicles (such as cars, trucks, SUVs, crossovers, vans, ships, aircraft, all-terrain vehicles, recreational vehicles, or other suitable forms of transport) typically include braking systems, such as electromechanical braking (EMB) systems, hydraulic braking systems, or other suitable braking systems. These braking systems generally control various aspects of the vehicle's braking, including providing braking assistance to the operator, anti-lock braking, traction control, etc.

[0019] This disclosure provides integral-integral-derivative (PID) or proportional-integral-derivative (PID) control strategies to optimize controller anti-saturation and response lag under high dynamic operating conditions without compromising steady-state control effectiveness.

[0020] Figure 1 A vehicle 12 based on the principles of this disclosure is generally shown. Vehicle 12 includes four wheels 14 and may include any suitable vehicle, such as a car, truck, SUV, minivan, crossover, any other passenger vehicle, any suitable commercial vehicle, or any other suitable vehicle. Although vehicle 12 is illustrated as a passenger vehicle with wheels 14 and used on a road, the principles of this disclosure can be applied to other vehicles, such as airplanes, ships, trains, drones, or other suitable vehicles.

[0021] Figure 1 A schematic block diagram of a braking system 10 in a vehicle 12 is shown. The braking system 10 can represent an EMB system with a conventional design. The braking system 10 includes four electromechanical braking units (EBUs) 20a, 20b, 20c, and 20d. EBUs 20a, 20b, 20c, and 20d include: a right front (FR) EBU 20a, a left front (FL) EBU 20b, a right rear EBU 20c, and a left rear EBU 20d. Each of the EBUs 20a, 20b, 20c, and 20d is configured to apply braking force to the corresponding wheel in the wheel 14. The braking system 10 also includes a first brake pedal assembly 22 having a brake pedal 21 for actuation by the operator of the vehicle 12. The first brake pedal assembly 22 includes two position sensors 82a and 82b (in... Figure 4 (As shown in the diagram) and configured to generate two independent brake actuation signals 26a and 26b, which respectively represent the actuation intensity of the brake pedal 21. Brake actuation signals 26a and 26b can indicate the position of the brake pedal 21 or the amount of force applied to the brake pedal 21. However, brake actuation signals 26a and 26b can also indicate another related parameter, such as the hydraulic fluid pressure in the brake circuit coupled to the brake pedal 21.

[0022] The braking system 10 also includes dual integrated braking units (IBUs) 24a and 24b, each including a first IBU 24a and a second IBU 24b electrically isolated from the first IBU 24a for redundancy. The first IBU 24a is configured to receive a first brake actuation signal 26a from the first brake pedal assembly 22 and transmit a first brake communication signal to each of the EBUs 20a, 20b, 20c, and 20d via a first communication network 28a, thereby causing each of the EBUs 20a, 20b, 20c, and 20d to apply a corresponding braking force to slow down the vehicle. The second IBU 24b is configured to receive a second brake actuation signal 26b from the first brake pedal assembly 22 and transmit a second brake communication signal to each of the EBUs 20a, 20b, 20c, and 20d via the second communication network 28b, thereby causing each of the EBUs 20a, 20b, 20c, and 20d to apply a corresponding braking force to slow down the vehicle. The first communication network 28a and the second communication network 28b may each use a Controller Area Network (CAN) architecture (also known as a CAN bus). However, either or both of the first communication network 28a and / or the second communication network 28b may include different communication architectures, such as Local Interconnect Network (LIN), Ethernet, FlexRay, Data Distribution Service (DDS), or other hardware and / or software standards.

[0023] Figure 2 A schematic block diagram of the enhanced EBU 50 is shown. Figure 2 The enhanced EBU 50 shown can be used in any one or all of the EBUs 20a, 20b, 20c, and 20d in the braking system 10. As shown, the enhanced EBU 50 includes a first CAN interface 60 for communicating with the first IBU 24a via a first communication network 28a. The enhanced EBU 50 also includes a second CAN interface 62 for communicating with the second IBU 24b via a second communication network 28b. Therefore, the first CAN interface 60 and the second CAN interface 62 provide bidirectional redundancy to ensure that braking command signals can be transmitted even in the event of a failure of a single component.

[0024] The enhanced EBU 50 also includes a processor 52 coupled to a storage memory 54. The processor 52 is also functionally connected to each of the first CAN interface 60, the second CAN interface 62, and the I / O device 64 to monitor each of the braking communication signals and Boolean signals 30. The storage memory 54 stores instructions, such as program code executed by the processor 52, in an instruction storage 56. The storage memory 54 also includes a data storage 58 for storing data that will be used by the processor 52. The data storage 58 may record, for example, the values ​​of parameters passed to the processor 52 and / or the results of functions calculated by the processor 52.

[0025] The enhanced EBU 50 also includes a driver 70 coupled to the electric motor 72 and the braking mechanism 74. The processor 52 sends torque commands. The power is transmitted to the driver 70 to supply power to the electric motor 72, thereby causing the electric motor 72 to generate a corresponding output torque for actuating the braking mechanism 74. However, the processor 52 can transmit different commands (such as voltage commands or current commands) for controlling the electric motor 72, which have different actual clamping forces that cause the electric motor 72 to actuate the braking mechanism 74 to generate braking forces of varying strengths for controlling the vehicle 12. A similar effect.

[0026] The braking mechanism 74 may include, for example, a caliper configured to clamp the rotor between a pair of brake pads. Alternatively, the braking mechanism 74 may include one or more brake shoes that expand to engage the inner surface of the brake drum. The drive 70 may include, for example, an inverter or H-bridge, for supplying alternating current (AC) or direct current (DC) power to the electric motor 72 to cause the electric motor 72 to apply an actual clamping force in the braking mechanism 74. This causes vehicle 12 to slow down. Actual clamping force This can describe the force applied by the paired brake pads to clamp the rotor. Alternatively or additionally, the actual clamping force... This can describe the force applied by one or more brake shoes to engage the inner surface of the brake drum. The processor 52 can be programmed or otherwise configured to change the actual clamping force. To match the requested clamping force Request clamping force The clamping force can be determined by the dual integrated braking units (IBU) 24a, 24b based on the actuation strength of the brake pedal 21. It can be determined by another source and / or for another purpose (such as for traction control or torque vectoring).

[0027] The enhanced EBU 50 also includes a mechanism for sensing the actual clamping force applied by the braking mechanism 74. The force sensor 76 may include, for example, a load cell or a pressure sensor, for measuring an indication of the actual clamping force applied by the braking mechanism 74. The physical characteristics. Force sensor 76 can be integrated into the enhanced EBU 50, such as... Figure 2 As shown. Alternatively, the force sensor 76 can be located external to the enhanced EBU 50 and functionally connected to the enhanced EBU 50.

[0028] Figure 3 The command for generating torque is shown. A schematic block diagram of a motor controller. Alternatively, the motor controller can be configured to generate different control signals, such as voltage commands or current commands, for changing the force and / or speed generated by the electric motor 72. The motor controller includes a subtractor 78, which subtracts the actual clamping force... Subtract the requested clamping force To calculate clamping force deviation Clamping force deviation It can be called an error signal because it indicates the condition that needs to be corrected by the action of the electric motor 72. Figure 3 The motor controller shown also includes a proportional-integral-derivative (PID) control loop 80, which is based on clamping force deviation. Calculate torque command .

[0029] The PID control loop 80 includes a first gain block 82, which is configured to cause a clamping force deviation. Multiply by the proportional gain value K p The PID control loop 80 also includes an adder 84, which is configured to calculate the initial voltage command based on the output of the first gain block 82. v ctrlThe PID control loop 80 also includes an integrator 86, which is configured to calculate the clamping force deviation. The integral. The PID control loop 80 also includes a second gain block 88, which is configured to adjust the clamping force deviation. The integral multiplied by the integral gain value K i The PID control loop 80 also includes a differential calculator 90, which is configured to calculate the clamping force deviation. The time derivative. The PID control loop 80 also includes a third gain block 92, which is configured to adjust the clamping force deviation. The differential multiplied by the derivative gain value K d The outputs of the second gain block 88 and the third gain block 92 are respectively provided to the adder 84, which calculates the torque command based on the sum of the outputs of the first gain block 82, the second gain block 88, and the third gain block 92. In some embodiments, the PID control loop 80 may not include a derivative term or its derivative gain may be zero. If the derivative term is omitted or is zero, the PID control loop 80 may be referred to as a proportional-integral (PI) control loop.

[0030] Similarly, Figure 3 As shown, the integral control enable signal IntCtrl_Enable The second gain block 88 is also provided to the PID control loop 80. The second gain block 88 may require an integral control enable signal. IntCtrl_Enable This enables the second gain block 88 to function. The second gain block 88 can be configured to activate upon the integral control enable signal. IntCtrl_Enable When in an invalid state, it outputs zero or no signal. For example, in some embodiments, unless the integral control is enabled, it outputs zero or no signal. IntCtrl_Enable It is in an effective state; otherwise, the integral gain value is... K i It can be set to zero. A valid state can represent a logical "true" state, which can be represented as a Boolean value.

[0031] Figure 4 A flowchart is shown illustrating the steps in a first method 100 for determining the operating state of an electromechanical braking unit according to the principles of this disclosure. The first method 100 may be repeated periodically or cyclically. In some cases, the first method 100 may be repeated indefinitely. The first method 100 may be repeated at fixed cyclic intervals.

[0032] Method 100 calculates the requested clamping force at step 102. Changes in demand force Specifically, requesting changes in force. Calculate as described in equation (1): (1) in, It is the current time. t The requested clamping force ,and It is the step size of the previous time. t The clamping force requested at point -1 .

[0033] The first method 100 determines the change in the requested force at step 104. Is it greater than or equal to the clamping threshold? F ClampThrd Clamping threshold F ClampThrd This can be a constant, such as a predetermined value. Alternatively, a clamping threshold. F ClampThrd It can be a variable that can be dynamically adjusted.

[0034] If the demand force changes Greater than or equal to the clamping threshold F ClampThrd That is, if the determination at step 104 has a positive (Y) result, then the first method 100 proceeds to setting the clamping mark at step 106. ClampFlag Equals 1. Set clamping mark. ClampFlag An operation equal to 1 is considered effective when recording the operating state of the EMB unit as a clamping request. In other words, the criterion used to determine the operating state of the EMB unit as a clamping request is the change in the requested force. Greater than or equal to the clamping threshold F ClampThrd .

[0035] If the demand force changes Not greater than or equal to the clamping threshold F ClampThrd That is, if the determination at step 104 has a negative (N) result, then the first method 100 proceeds to step 110 to determine the change in the requested force. Is it less than or equal to the first release threshold? F RelThrd1 First release threshold F RelThrd1 This can be a constant, such as a predetermined value. Alternatively, a first release threshold. F RelThrd1 It can be a variable that can be dynamically adjusted.

[0036] If the demand force changes Less than or equal to the first release threshold F RelThrd1That is, if the determination at step 110 has a positive (Y) result, then the first method 100 proceeds to setting the clamping mark. ClampFlag The value is equal to 0, thus recording the operational status of the EMB unit as a definite result of the release request.

[0037] If the demand force changes Not less than or equal to the first release threshold F RelThrd1 That is, if the determination at step 110 has a negative (N) result, then the first method 100 proceeds to step 114 to determine the change in the requested force. Is it less than or equal to the second release threshold? F RelThrd2 Second release threshold F RelThrd2 This can be a constant, such as a predetermined value. Alternatively, a second release threshold. F RelThrd2 It can be a variable that can be dynamically adjusted.

[0038] If the demand force changes Not less than or equal to the second release threshold F RelThrd2 That is, if the determination at step 114 has a negative (N) result, then the first method 100 proceeds to step 116 to set the release counter. RelCount The value is equal to 0. Additionally, step 116 includes clamping the mark. ClampFlag Set to previous value CampFlag_Prev It can be represented by a clamping flag after a previous iteration of the first method 100. ClampFlag The value of .

[0039] If the demand force changes Less than or equal to the second release threshold F RelThrd2 That is, if the determination at step 114 has a positive (Y) result, then the first method 100 proceeds to step 118 to increment the release counter. RelCount Step 118 may include, for example, setting a release counter. RelCount It is equal to itself plus 1.

[0040] After completing step 118, the first method 100 determines the release counter at step 120. RelCount Is it greater than or equal to the release count threshold? RelCntThrd Release count threshold RelCntThrd It can be a constant, such as a predetermined value. In some embodiments, a release count threshold is used. RelCntThrd It can be equal to 10. However, the release count threshold... RelCntThrd These can have different constant values. Alternatively, a release count threshold can be used. RelCntThrd It can be a variable that can be dynamically adjusted.

[0041] Steps 114-120 can be used together to determine the change in requested force. equal to the release count threshold RelCntThrd The value remains below the second release threshold for a predetermined period of time, multiplied by the cycle interval of the first method 100. F RelThrd2 .

[0042] If the counter is released RelCount Not greater than or equal to the release count threshold RelCntThrd That is, if the determination at step 120 has a negative (N) result, then the first method 100 proceeds to step 122 to clamp the mark. ClampFlag Set to previous value CampFlag_Prev It can be represented by a clamping flag after a previous iteration of the first method 100. ClampFlag The value of .

[0043] If the counter is released RelCount Greater than or equal to the release count threshold RelCntThrd That is, if the determination at step 120 has a positive (Y) result, then the first method 100 proceeds to setting the clamping mark at step 124. ClampFlag The value is equal to 0, thus recording the operational status of the EMB unit as a definite result of the release request.

[0044] Figure 5 A flowchart is shown illustrating the steps in a second method 150 for determining the first and second conditions for enabling integral control of the proportional-integral-derivative (PID) control loop of the electromechanical braking unit. The second method 150 may be part of and synchronized with the first method 100. Alternatively, the second method 150 may be independent of and / or asynchronous with the first method 100.

[0045] The second method 150 addresses the clamping force deviation at step 152. Calculate the required clamping force With actual clamping force The difference between them. Step 152 can represent the function of subtractor 78. Specifically, the clamping force deviation. Calculate as described in equation (2): (2)

[0046] The second method 150 determines at step 154 ​​whether the operating status of the EMB unit is a clamping request. Specifically, step 154 ​​determines the clamping flag. ClampFlag Is it equal to 1?

[0047] If the operating state of the EMB unit is a clamping request, that is, if the determination at step 154 ​​has a positive (Y) result, then the second method 150 proceeds to step 156 to determine the clamping force deviation. Is it less than or equal to the clamping deviation threshold? F ClampDevThrd Clamping deviation threshold F ClampDevThrd This can be a constant, such as a predetermined value. Alternatively, it could be a clamping deviation threshold. F ClampDevThrd It can be a variable that can be dynamically adjusted.

[0048] If the clamping force is off Less than or equal to the clamping deviation threshold F ClampDevThrd That is, if the determination at step 156 has a positive (Y) result, then the second method 150 proceeds to step 158 to enable the integral control signal. IntCtrl_ Enable Set it to 1 to enable integral control of PID control loop 80.

[0049] If the operating state of the EMB unit is a release request, that is, if the determination at step 154 ​​has a negative (N) result, then the second method 150 proceeds to step 160 to determine the clamping force deviation. Is it greater than or equal to the release deviation threshold? F RelDevThrd Release deviation threshold F RelDevThrd This can be a constant, such as a predetermined value. Alternatively, a deviation threshold can be released. F RelDevThrd It can be a variable that can be dynamically adjusted.

[0050] If the clamping force is off Greater than or equal to the release deviation threshold F RelDevThrd That is, if the determination at step 160 has a positive (Y) result, then the second method 150 proceeds to step 162 to enable the integral control signal. IntCtrl_ Enable Set it to 1 to enable integral control of PID control loop 80.

[0051] Figure 6A flowchart is shown illustrating the steps in a third method 180 for determining a third condition for enabling integral control of the proportional-integral-derivative (PID) control loop of the electromechanical braking unit. The third method 180 may be part of and synchronized with the first method 100 and / or the second method 150. Alternatively, the third method 180 may be independent of and asynchronous with the first method 100 and the second method 150.

[0052] The third method 180 calculates the requested clamping force at step 182. Changes in demand force As described above with reference to step 102 of the first method 100, the requested clamping force can be calculated using equation (1). Changes in demand force .

[0053] The third method 180 also calculates the actual clamping force at step 184. Actual force change Specifically, changes in actual force Calculate as described in equation (3): (3) in, It is the current time. t Actual clamping force at the location ,and It is the step size of the previous time. t Actual clamping force at -1 .

[0054] The second method 150 determines at step 186 whether each of the following conditions is met: The absolute value of the change in demand force Is it less than or equal to the force request change threshold? F ClmpReqChg_Thrd ; absolute value of actual force change Is it less than or equal to the actual force change threshold? F ClmpActChg_Thrd ;as well as Absolute value of clamping force deviation Is it less than or equal to the force deviation threshold? F dev_Thrd .

[0055] Force request change threshold F ClmpReqChg_Thrd actual force change threshold F ClmpActChg_Thrd Force deviation thresholdF dev_Thrd Each of these can be a constant, such as a predetermined value. Alternatively, the force requests a change threshold. F ClmpReqChg_Thrd actual force change threshold F ClmpActChg_Thrd and / or force deviation threshold F dev_Thrd Any one or all of them can be variables that can be dynamically adjusted.

[0056] If it is any of the following: the absolute value of the change in the requested force. Less than or equal to the force request change threshold F ClmpReqChg_Thrd The absolute value of the actual change in force Less than or equal to the actual force change threshold F ClmpActChg_Thrd ; and the absolute value of the clamping force deviation Less than or equal to the force deviation threshold F dev_Thrd (That is, if the determination at step 186 has a positive (Y) result), then the third method 180 proceeds to setting the integral control enable signal at step 188. IntCtrl_Enable The value equals 1, thus enabling integral control of the PID control loop 80.

[0057] If the integral control enable signal is not given at any of steps 158, 162, or 188 IntCtrl_ Enable Setting it to 1 will enable the integral control signal. IntCtrl_Enable Setting it to 0 disables integral control of the PID control loop 80. This can be done, for example, during the initialization of the first method 100 or before starting the second method 150.

[0058] Figures 7A to 7G A flowchart is shown, outlining the steps of a fourth method 200 for controlling an electromechanical braking (EMB) unit in a vehicle, according to the principles of this disclosure. According to some embodiments of this disclosure, the fourth method 200 may be executed by a processor 52 in an enhanced EBU 50. It will be understood from this disclosure that the sequence of operations within the method is not limited to... Figures 7A to 7G The order of execution shown may be performed, but may be performed in one or more different orders as applicable, in accordance with this disclosure.

[0059] The fourth method 200 includes adjusting the clamping force deviation at step 202. ) is determined to be the requested clamping force ( ) and actual clamping force ( The difference between them. For example, processor 52 can execute instructions to implement step 152 of the second method 150.

[0060] The fourth method 200 includes using a proportional-integral-derivative (PID) control loop at step 204 and based on the clamping force deviation ( The processor 52 determines the commands used for the brake actuator. For example, the processor 52 can execute instructions to implement the PID control loop 80. Commands for the brake actuator may include torque commands. Or other commands, such as voltage or current commands for electric motors used in brake actuators.

[0061] The fourth method 200 includes determining the requested clamping force at step 206. The change in the demand force () For example, processor 52 can execute instructions to implement step 102 of the first method 100.

[0062] The fourth method 200 includes, at step 208, a change in the requested force ( The operating state of the EMB unit is determined to be either a clamping request or a release request. For example, the processor 52 may execute instructions to implement steps 104-124 of the first method 100.

[0063] The fourth method 200 includes selectively enabling integral control of the PID control loop based on the operating state of the EMB unit at step 210. For example, the processor 52 may execute instructions to implement steps 154-162 of the second method 150 and / or steps 184-188 of the third method 180.

[0064] In some embodiments, the fourth method 200 further includes Figure 7B Steps 252-254 are shown. The fourth method 200 may include, at step 252, requesting a change in force ( ) and clamping threshold ( F ClampThrd ) to compare in order to determine the change in requested force ( Not less than the clamping threshold ( F ClampThrd For example, processor 52 can execute instructions to implement step 104 of the first method 100. The fourth method 200 may also include, at step 254, a response to a change in requested force (…). Not less than the clamping threshold ( F ClampThrd The processor 52 determines the operating state of the EMB unit as a clamping request. For example, the processor 52 can execute instructions to implement step 106 of the first method 100.

[0065] In some embodiments, the fourth method 200 further includes Figure 7C Steps 262-266 are shown. The fourth method 200 may include, at step 262, requesting a change in force ( ) and clamping threshold ( F ClampThrd ) to compare in order to determine the change in requested force ( ) not greater than the clamping threshold ( F ClampThrd For example, processor 52 can execute instructions to implement step 104 of the first method 100.

[0066] The fourth method 200 may also include changing the requested force at step 264. ) and the first release threshold ( F RelThrd1 ) to compare in order to determine the change in requested force ( ) not greater than the first release threshold ( F RelThrd1 For example, processor 52 can execute instructions to implement step 110 of the first method 100.

[0067] The fourth method 200 may also include, at step 266, a response to a change in the requested force ( ) not greater than the clamping threshold ( F ClampThrd And request force change ( ) not greater than the first release threshold ( F RelThrd1 The processor 52 determines the operating state of the EMB unit as a release request. For example, the processor 52 can execute instructions to implement step 112 of the first method 100.

[0068] In some embodiments, the fourth method 200 further includes Figure 7D Steps 272-280 are shown. The fourth method 200 may include, at step 272, requesting a change in force ( ) and clamping threshold ( F ClampThrd ) to compare in order to determine the change in requested force ( ) not greater than the clamping threshold ( F ClampThrd For example, processor 52 can execute instructions to implement step 104 of the first method 100.

[0069] The fourth method 200 may also include changing the requested force at step 274. ) and the first release threshold ( F RelThrd1 ) to compare in order to determine the change in requested force ( Not less than the first release threshold (F RelThrd1 For example, processor 52 can execute instructions to implement step 110 of the first method 100.

[0070] The fourth method 200 may also include changing the requested force at step 276. ) and the second release threshold ( F RelThrd2 ) to compare in order to determine the change in requested force ( ) not greater than the second release threshold ( F RelThrd2 For example, processor 52 can execute instructions to implement step 114 of the first method 100.

[0071] The fourth method 200 may further include determining the change in the requested force at step 278. ) Remain below the second release threshold within the predetermined time period ( F RelThrd2 For example, processor 52 can execute instructions to implement steps 114-120 in multiple iterations of the first method 100.

[0072] The fourth method 200 may also include responding to a change in the requested force at step 280. ) Remain below the second release threshold within the predetermined time period ( F RelThrd2 The processor 52 determines the operating state of the EMB unit as a release request. For example, the processor 52 can execute instructions to implement step 124 of the first method 100.

[0073] In some embodiments, step 210 of the fourth method 200 further includes Figure 7E Steps 302-304 are shown. Step 210 may include determining the operating state of the EMB unit as a clamping request at step 302. For example, processor 52 may execute instructions to implement step 154 ​​of the second method 150.

[0074] Step 210 may also include adjusting the clamping force deviation at step 304. ) and clamping deviation threshold ( F ClampDevThrd ) are compared to determine the clamping force deviation ( ) not greater than the clamping deviation threshold ( F ClampDevThrd For example, processor 52 can execute instructions to implement step 156 of the second method 150.

[0075] Step 210 may also include enabling integral control of the PID control loop in response to each of the following: the EMB unit is in a clamping request state, and the clamping force deviation is ( ) not greater than the clamping deviation threshold ( F ClampDevThrd For example, processor 52 can execute instructions to implement step 158 of the second method 150 in response to each of steps 154 and 156 having a positive (Y) result.

[0076] In some embodiments, step 210 of the fourth method 200 further includes Figure 7F Steps 312-314 are shown. Step 210 may include determining the operating state of the EMB unit as a release request at step 312. For example, processor 52 may execute instructions to implement step 154 ​​of the second method 150.

[0077] Step 210 may also include adjusting the clamping force deviation at step 314. ) and release deviation threshold ( F RelDevThrd ) are compared to determine the clamping force deviation ( Not less than the release deviation threshold ( F RelDevThrd For example, processor 52 can execute instructions to implement step 160 of the second method 150.

[0078] Step 210 may also include enabling integral control of the PID control loop in response to each of the following: the EMB unit is in a release request state, and the clamping force deviation ( Not less than the release deviation threshold ( F RelDevThrd For example, processor 52 can execute instructions to implement step 162 of the second method 150 in response to step 154 ​​having a negative (N) result and step 156 having a positive (Y) result.

[0079] In some embodiments, step 210 of the fourth method 200 further includes Figure 7G Steps 322-330 are shown. Step 210 may include determining the requested clamping force at step 322. The change in the demand force () For example, processor 52 can execute instructions to implement step 182 of the third method 180.

[0080] Step 210 may also include, at step 324, the absolute value of the change in the requested force ( ) and force request change threshold ( F ClmpReqChg_Thrd ) to compare in order to determine the absolute value of the change in the requested force ( ) not greater than the force request change threshold ( F ClmpReqChg_ThrdFor example, processor 52 can execute instructions to perform the first comparison in step 186 of the third method 180.

[0081] Step 210 may also include determining the actual clamping force at step 326. Actual force change () For example, processor 52 can execute instructions to implement step 184 of the third method 180.

[0082] Step 210 may also include, at step 328, the absolute value of the actual force change ( ) and the actual force change threshold ( F ClmpActChg_Thrd To compare and determine the absolute value of the actual force change ( ) not greater than the actual force change threshold ( F ClmpActChg_Thrd For example, processor 52 can execute instructions to perform the second comparison in step 186 of the third method 180.

[0083] Step 210 may also include, at step 330, setting the absolute value of the clamping force deviation ( ) and clamping force deviation threshold ( F dev_Thrd ) compare to determine the absolute value of the clamping force deviation ( ) not greater than the clamping force deviation threshold ( F dev_Thrd For example, processor 52 can execute instructions to perform the third comparison in step 186 of the third method 180.

[0084] Step 210 may also include enabling integral control of the PID control loop only in response to at least one of the following: a) The EMB unit is in the clamping request state, and the clamping force deviation is ( ) not greater than the clamping deviation threshold ( F ClampDevThrd ), b) The EMB unit is in the release request state, and the clamping force deviation is ( Not less than the release deviation threshold ( F RelDevThrd ), and / or c) All of the following: i. The absolute value of the change in demand force ( ) not greater than the force request change threshold ( F ClmpReqChg_Thrd ), ii. The absolute value of the actual change in force ( ) not greater than the actual force change threshold ( FClmpActChg_Thrd ),as well as iii. The absolute value of the clamping force deviation ( ) not greater than the force deviation threshold ( F dev_Thrd ).

[0085] Referring to step 210, case a) can indicate that integral control is enabled at step 158 of the second method 150; case b) can indicate that integral control is enabled at step 162 of the second method 150; and case c) can indicate that integral control is enabled at step 188 of the third method 180. If none of cases a)-c) exist, integral control of the PID control loop can be disabled. Conditions i-iii in case c) can respectively represent the three comparison results in step 186 of the third method 180.

[0086] The foregoing discussion is intended to illustrate the principles and various embodiments of this disclosure. Once the foregoing disclosure is fully understood, many variations and modifications will become apparent to those skilled in the art. The appended claims are intended to be construed as covering all such variations and modifications.

[0087] Ordinal numbers such as “first,” “second,” and “third” can be used to represent different structures, which may be part of the same system or component or different systems or components. Unless the specification clearly describes multiple related structures, such ordinal numbers should not be interpreted as representing any number of related structures in any given system or component.

[0088] The word “example” is used herein to mean something used as an example, illustration, or description. Any aspect or design described herein as an “example” is not necessarily to be construed as being more preferred or advantageous than other aspects or designs. Rather, the use of the word “example” is intended to present a concept in a specific manner. As used in this application, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless otherwise stated or clearly apparent from the context, “X comprises A or B” is intended to mean any natural inclusion. That is, if X comprises A; X comprises B; or X comprises both A and B, then “X comprises A or B” is satisfied in any of the foregoing cases. Additionally, the article “a / an” used in this application and the appended claims should generally be interpreted as meaning “one or more” unless otherwise stated or clearly apparent from the context to the singular form. Furthermore, unless so described, the use of the terms “implementation” or “an embodiment” throughout the document is not intended to refer to the same embodiment or implementation.

[0089] The systems, algorithms, methods, and instructions described herein can be implemented in hardware, software, or any combination thereof. Hardware may include, for example, a computer, intellectual property (IP) core, application-specific integrated circuit (ASIC), programmable logic array, optical processor, programmable logic controller, microcode, microcontroller, server, microprocessor, digital signal processor, or any other suitable circuit. In the claims, the term "processor" should be understood to include any of the foregoing hardware, individually or in combination. The terms "signal" and "data" are used interchangeably.

[0090] As used herein, the term "module" can include a packaged functional hardware unit designed for use with other components, a set of instructions executable by a controller (e.g., a processor executing software or firmware), processing circuitry configured to perform a specific function, and self-contained hardware or software components that interface with a larger system. For example, a module can include an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), circuitry, digital logic circuitry, analog circuitry, a combination of discrete circuitry, gate circuits, and other types of hardware, or combinations thereof. In other embodiments, a module can include a memory storing instructions executable by a controller to implement the features of the module.

[0091] Furthermore, in one respect, for example, the system described herein can be implemented using a general-purpose computer or general-purpose processor with a computer program that, when executed, implements any of the corresponding methods, algorithms, and / or instructions described herein. Additionally or alternatively, for example, a special-purpose computer / processor may be utilized, which may contain additional hardware for implementing any of the methods, algorithms, or instructions described herein.

[0092] Furthermore, all or part of the embodiments of this disclosure may take the form of a computer program product accessible from, for example, a computer-usable or computer-readable medium. A computer-usable or computer-readable medium may be, for example, any means capable of tangibly containing, storing, conveying, or transmitting a program for use by or in conjunction with any processor. The medium may be, for example, an electrical, magnetic, optical, electromagnetic, or semiconductor device. Other suitable media may also be used.

[0093] The above embodiments, implementations, and aspects have been described to allow for easy understanding of this disclosure and do not limit it. Rather, this disclosure is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims, which should be interpreted in the broadest possible sense to cover all such modifications and equivalent structures permitted by law.

Claims

1. A method for controlling an electromechanical braking EMB unit in a vehicle, comprising: The clamping force deviation ( ) is determined to be the requested clamping force ( ) and actual clamping force ( The difference between them; Using a proportional-integral-derivative (PID) control loop and based on the clamping force deviation ( ) to determine the commands used for the brake actuator; The operating state of the EMB unit is determined to be either a clamping request or a release request. as well as Based on the operating state of the EMB unit, integral control of the PID control loop is selectively enabled.

2. The method of claim 1, further comprising determining the requested clamping force ( The change in the demand force () ), in, determining the operating state of the EMB unit based on the request force variation ) 3. The method according to claim 2, further comprising: comparing the requested force change ( ) to a clamp threshold ( F ClampThrd ) to determine that the requested force change ( ) is not less than the clamp threshold ( F ClampThrd ); and In response to the requested force change ( ) is not less than the clamping threshold ( F ClampThrd The operating state of the EMB unit is determined as the clamping request.

4. The method according to claim 2, further comprising: Change the requested force ( ) and clamping threshold ( F ClampThrd ) are compared to determine the change in the requested force ( ) is not greater than the clamping threshold ( F ClampThrd ); Change the requested force ( ) and the first release threshold ( F RelThrd1 ) are compared to determine the change in the requested force ( ) is not greater than the first release threshold ( F RelThrd1 );as well as In response to the requested force change ( ) is not greater than the clamping threshold ( F ClampThrd ), and the requested force change ( ) is not greater than the first release threshold ( F RelThrd1 The operation state of the EMB unit is determined as the release request.

5. The method according to claim 2, further comprising: Change the requested force ( ) and clamping threshold ( F ClampThrd ) are compared to determine the change in the requested force ( ) is not greater than the clamping threshold ( F ClampThrd ); Change the requested force ( ) and the first release threshold ( F RelThrd1 ) are compared to determine the change in the requested force ( ) is not less than the first release threshold ( F RelThrd1 ); Change the requested force ( ) and the second release threshold ( F RelThrd2 ) are compared to determine the change in the requested force ( ) is not greater than the second release threshold ( F RelThrd2 ); Determine the change in the requested force ( ) remains below the second release threshold within the predetermined time period ( F RelThrd2 );as well as In response to the requested force change ( ) remains below the second release threshold during the predetermined time period ( F RelThrd2 The operation state of the EMB unit is determined as the release request.

6. The method according to claim 1, wherein, Selectively enabling the integral control of the PID control loop further includes: The operating state of the EMB unit is determined as the clamping request; and The clamping force deviation ( ) and clamping deviation threshold ( F ClampDevThrd ) are compared to determine the clamping force deviation ( ) is not greater than the clamping deviation threshold ( F ClampDevThrd ), The selective activation of the integral control of the PID control loop includes activating the integral control of the PID control loop in response to the following: the operating state of the EMB unit is the clamping request, and the clamping force deviation ( ) is not greater than the clamping deviation threshold ( F ClampDevThrd ).

7. The method according to claim 1, wherein, Selectively enabling the integral control of the PID control loop further includes: The operation state of the EMB unit is determined as the release request; and The clamping force deviation ( ) and release deviation threshold ( F RelDevThrd ) are compared to determine the clamping force deviation ( ) is not less than the release deviation threshold ( F RelDevThrd ), Selectively enabling the integral control of the PID control loop includes enabling the integral control of the PID control loop in response to each of the following: the operating state of the EMB unit is the release request, and the clamping force deviation ( ) is not less than the release deviation threshold ( F RelDevThrd ).

8. The method according to claim 1, wherein, Selectively enabling the integral control of the PID control loop further includes: Determine the requested clamping force ( The change in the demand force () ); The absolute value of the change in the requested force ( ) and force request change threshold ( F ClmpReqChg_Thrd ) are compared to determine the absolute value of the change in the requested force ( The force request change threshold is not greater than the threshold value. F ClmpReqChg_Thrd );as well as The absolute value of the clamping force deviation ( ) and force deviation threshold ( F dev_Thrd ) are compared to determine the absolute value of the clamping force deviation ( ) is not greater than the force deviation threshold ( F dev_Thrd ),as well as The selective activation of the integral control of the PID control loop includes activating the integral control of the PID control loop in response to each of the following: The absolute value of the change in the requested force ( The force request change threshold is not greater than the threshold value. F ClmpReqChg_Thrd ),as well as The absolute value of the clamping force deviation ( ) is not greater than the force deviation threshold ( F dev_Thrd ).

9. The method according to claim 1, wherein, Selectively enabling the integral control of the PID control loop further includes: Determine the actual clamping force ( Actual force change () ); The absolute value of the actual force change ( ) and the actual force change threshold ( F ClmpActChg_Thrd ) are compared to determine the absolute value of the actual force change ( The actual change in force is not greater than the threshold value. F ClmpActChg_Thrd );as well as The absolute value of the clamping force deviation ( ) and clamping force deviation threshold ( F dev_Thrd ) are compared to determine the absolute value of the clamping force deviation ( The clamping force deviation threshold is not greater than the threshold value. F dev_Thrd ), The selective activation of the integral control of the PID control loop includes activating the integral control of the PID control loop in response to each of the following: The absolute value of the actual force change ( The actual change in force is not greater than the threshold value. F ClmpActChg_Thrd ),as well as The absolute value of the clamping force deviation ( ) is not greater than the force deviation threshold ( F dev_Thrd ).

10. The method according to claim 1, wherein, Selectively enabling the integral control of the PID control loop further includes: The clamping force deviation ( ) and clamping deviation threshold ( F ClampDevThrd ) are compared to determine the clamping force deviation ( ) is not greater than the clamping deviation threshold ( F ClampDevThrd ), The clamping force deviation ( ) and release deviation threshold ( F RelDevThrd ) are compared to determine the clamping force deviation ( ) is not less than the release deviation threshold ( F RelDevThrd ), Determine the requested clamping force ( The change in the demand force () ); The absolute value of the change in the requested force ( ) and force request change threshold ( F ClmpReqChg_Thrd ) are compared to determine the absolute value of the change in the requested force ( The force request change threshold is not greater than the threshold value. F ClmpReqChg_Thrd ); Determine the actual clamping force ( Actual force change () ); The absolute value of the actual force change ( ) and the actual force change threshold ( F ClmpActChg_Thrd ) are compared to determine the absolute value of the actual force change ( The actual change in force is not greater than the threshold value. F ClmpActChg_Thrd ), The absolute value of the clamping force deviation ( ) and clamping force deviation threshold ( F dev_Thrd ) are compared to determine the absolute value of the clamping force deviation ( The clamping force deviation threshold is not greater than the threshold value. F dev_Thrd ),as well as The selective activation of the integral control of the PID control loop includes activating the integral control of the PID control loop only in response to at least one of the following: The operating state of the EMB unit is the clamping request, and the clamping force deviation ( ) is not greater than the clamping deviation threshold ( F ClampDevThrd ), The operating state of the EMB unit is the release request, and the clamping force deviation ( ) is not less than the release deviation threshold ( F RelDevThrd ),or All of the following: The absolute value of the change in the requested force ( The force request change threshold is not greater than the threshold value. F ClmpReqChg_Thrd ), The absolute value of the actual force change ( The actual change in force is not greater than the threshold value. F ClmpActChg_Thrd ),as well as The absolute value of the clamping force deviation ( ) is not greater than the force deviation threshold ( F dev_Thrd ).

11. A braking system for a vehicle, comprising: An electromechanical braking EMB unit includes an actuator configured to apply an actual clamping force. To slow down the vehicle; as well as The controller is configured as follows: The clamping force deviation ( ) is determined to be the requested clamping force ( ) and the actual clamping force applied by the actuator ( The difference between them; Using a proportional-integral-derivative (PID) controller and based on the clamping force deviation ( ) to determine the commands used for the actuator; The operating state of the EMB unit is determined to be either a clamping request or a release request. as well as Based on the operating state of the EMB unit, integral control of the PID control loop is selectively enabled.

12. The braking system according to claim 11, wherein, The controller is also configured to: Determine the requested clamping force ( The change in the demand force () );as well as Based on the change in the requested force ( The operating state of the EMB unit is determined.

13. The braking system according to claim 12, wherein, The controller is also configured to: Change the requested force ( ) and clamping threshold ( F ClampThrd ) are compared to determine the change in the requested force ( ) is not less than the clamping threshold ( F ClampThrd );as well as In response to the requested force change ( ) is not less than the clamping threshold ( F ClampThrd The operating state of the EMB unit is determined as the clamping request.

14. The braking system according to claim 12, wherein, The controller is also configured to: Change the requested force ( ) and clamping threshold ( F ClampThrd ) are compared to determine the change in the requested force ( ) is not greater than the clamping threshold ( F ClampThrd ); Change the requested force ( ) and the first release threshold ( F RelThrd1 ) are compared to determine the change in the requested force ( ) is not greater than the first release threshold ( F RelThrd1 );as well as In response to the requested force change ( ) is not greater than the clamping threshold ( F ClampThrd And the requested force change ( ) is not greater than the first release threshold ( F RelThrd1 The operation state of the EMB unit is determined as the release request.

15. The braking system according to claim 12, wherein, The controller is also configured to: Change the requested force ( ) and clamping threshold ( F ClampThrd ) are compared to determine the change in the requested force ( ) is not greater than the clamping threshold ( F ClampThrd ); Change the requested force ( ) and the first release threshold ( F RelThrd1 ) are compared to determine the change in the requested force ( ) is not less than the first release threshold ( F RelThrd1 ); Change the requested force ( ) and the second release threshold ( F RelThrd2 ) are compared to determine the change in the requested force ( ) is not greater than the second release threshold ( F RelThrd2 ); Determine the change in the requested force ( ) remains below the second release threshold within the predetermined time period ( F RelThrd2 );as well as In response to the requested force change ( ) remains below the second release threshold during the predetermined time period ( F RelThrd2 The operation state of the EMB unit is determined as the release request.

16. The braking system according to claim 11, wherein, The controller is also configured to: The operating state of the EMB unit is determined as the clamping request; and The clamping force deviation ( ) and clamping deviation threshold ( F ClampDevThrd ) are compared to determine the clamping force deviation ( ) is not greater than the clamping deviation threshold ( F ClampDevThrd ), The selective activation of the integral control of the PID control loop includes activating the integral control of the PID control loop in response to the following: the operating state of the EMB unit is the clamping request, and the clamping force deviation ( ) is not greater than the clamping deviation threshold ( F ClampDevThrd ).

17. The braking system according to claim 11, wherein, The controller is also configured to: The operation state of the EMB unit is determined as the release request; and The clamping force deviation ( ) and release deviation threshold ( F RelDevThrd ) are compared to determine the clamping force deviation ( ) is not less than the release deviation threshold ( F RelDevThrd ), Selectively enabling the integral control of the PID control loop includes enabling the integral control of the PID control loop in response to each of the following: the operating state of the EMB unit is the release request, and the clamping force deviation ( ) is not less than the release deviation threshold ( F RelDevThrd ).

18. The braking system according to claim 11, wherein, The controller is also configured to: Determine the requested clamping force ( The change in the demand force () ); The absolute value of the change in the requested force ( ) and force request change threshold ( F ClmpReqChg_Thrd ) are compared to determine the absolute value of the change in the requested force ( The force request change threshold is not greater than the threshold value. F ClmpReqChg_Thrd );as well as The absolute value of the clamping force deviation ( ) and force deviation threshold ( F dev_Thrd ) are compared to determine the absolute value of the clamping force deviation ( ) is not greater than the force deviation threshold ( F dev_Thrd ), The selective activation of the integral control of the PID control loop includes activating the integral control of the PID control loop in response to each of the following: The absolute value of the change in the requested force ( The force request change threshold is not greater than the threshold value. F ClmpReqChg_Thrd ),as well as The absolute value of the clamping force deviation ( ) is not greater than the force deviation threshold ( F dev_Thrd ).

19. The braking system according to claim 18, wherein, The controller is also configured to: Determine the actual clamping force ( Actual force change () ); The absolute value of the actual force change ( ) and the actual force change threshold ( F ClmpActChg_Thrd ) are compared to determine the absolute value of the actual force change ( The actual change in force is not greater than the threshold value. F ClmpActChg_Thrd ), The absolute value of the clamping force deviation ( ) and clamping force deviation threshold ( F dev_Thrd ) are compared to determine the absolute value of the clamping force deviation ( The clamping force deviation threshold is not greater than the threshold value. F dev_Thrd ),as well as The selective activation of the integral control of the PID control loop includes activating the integral control of the PID control loop in response to each of the following: The absolute value of the actual force change ( The actual change in force is not greater than the threshold value. F ClmpActChg_Thrd ),as well as The absolute value of the clamping force deviation ( ) is not greater than the force deviation threshold ( F dev_Thrd ).

20. The braking system according to claim 11, wherein, The controller is also configured to: The clamping force deviation ( ) and clamping deviation threshold ( F ClampDevThrd ) are compared to determine the clamping force deviation ( ) is not greater than the clamping deviation threshold ( F ClampDevThrd ), The clamping force deviation ( ) and release deviation threshold ( F RelDevThrd ) are compared to determine the clamping force deviation ( ) is not less than the release deviation threshold ( F RelDevThrd ), Determine the requested clamping force ( The change in the demand force () ); The absolute value of the change in the requested force ( ) and force request change threshold ( F ClmpReqChg_Thrd ) are compared to determine the absolute value of the change in the requested force ( The force request change threshold is not greater than the threshold value. F ClmpReqChg_Thrd ); Determine the actual clamping force ( Actual force change () ); The absolute value of the actual force change ( ) and the actual force change threshold ( F ClmpActChg_Thrd ) are compared to determine the absolute value of the actual force change ( The actual change in force is not greater than the threshold value. F ClmpActChg_Thrd );as well as The absolute value of the clamping force deviation ( ) and clamping force deviation threshold ( F dev_Thrd ) are compared to determine the absolute value of the clamping force deviation ( The clamping force deviation threshold is not greater than the threshold value. F dev_Thrd ), The selective activation of the integral control of the PID control loop includes activating the integral control of the PID control loop only in response to at least one of the following: The operating state of the EMB unit is the clamping request, and the clamping force deviation ( ) is not greater than the clamping deviation threshold ( F ClampDevThrd ), The operating state of the EMB unit is the release request, and the clamping force deviation ( ) is not less than the release deviation threshold ( F RelDevThrd ),or All of the following: The absolute value of the change in the requested force ( The force request change threshold is not greater than the threshold value. F ClmpReqChg_Thrd ), The absolute value of the actual force change ( The actual change in force is not greater than the threshold value. F ClmpActChg_Thrd ),as well as The absolute value of the clamping force deviation ( ) is not greater than the force deviation threshold ( F dev_Thrd ).

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