Control process and electromechanical brake system

Abstract

The present invention describes a solution for managing a tribological pair intended to promote braking, in such a way that the control process provides at least one algorithm for adjusting the position of at least one of the elements of the tribological pair, in order to ensure greater safety and efficiency in the actuation of the electromechanical brake system. More specifically, the algorithm compensates for the position of the element due to wear or over-adjustment, and also calibrates the position, using variables accessible within the brake system itself. The present invention pertains to the fields of mechanical, electrical, and electronic engineering applied to the automotive sector, and more specifically to brake systems and tribology.

Description

Control process and electromechanical braking system Field of Invention

[0001] The present invention falls within the fields of mechanical, electrical and electronic engineering focused on the automotive segment, more specifically, brake systems and tribology. Background of the Invention

[0002] Tribological pairs are formed by at least two components that exhibit relative motion to each other, causing friction. In the automotive sector, the friction between two components of a tribological pair is widely used for vehicle braking.

[0003] However, the fact that these components rub against each other repeatedly results in wear and tear, requiring periodic maintenance and replacement of at least one component of the tribological pair.

[0004] In vehicle brakes, pairs such as brake pads and discs or brake drums and linings are located in hard-to-see places, often hidden by the vehicle's wheel and tire. Therefore, visually inspecting this component is not simple, requiring the disassembly of vehicle components while the vehicle is stationary for this visual inspection.

[0005] Thus, the technology demands the possibility of more practical and efficient monitoring of the wear of the components of a tribological pair, especially when they are used as part of a vehicle's brake system, in order to detect the need for maintenance and / or replacement of these components.

[0006] Furthermore, the wear and tear on these components increases their spacing from one another when the brake is not applied, so the distance traveled for contact of the tribological pair increases with use, resulting in a serious risk for its use in braking, as it increases the response time of the brakes, reducing their efficiency.

[0007] For example, in disc brakes, the friction between the brake pad and the brake disc comes from the clamping force applied by the caliper or brake caliper. Thus, the Brake pad / disc wear reduces brake efficiency because it takes longer to reach the expected clamping force, which is often not achieved. Therefore, the greater the gap, the lower the brake performance; however, if the gap is too small, thermal issues with the pad or warping problems can cause a drag effect, also affecting the vehicle's braking.

[0008] In this way, the technique uses mechanisms that complement the brake actuation to compensate for this wear, involving complex couplings and sensors to read the wear and correct the expected spacing or clearance between the elements of the tribological pair.

[0009] As an example, document US20240246525A1 describes an electromechanical brake that implements a control method to maintain a predefined distance between the brake pad and the brake disc, that is, the predefined clearance between these elements. To achieve this, a controller continuously determines a position where contact occurs between the elements by detecting a sudden change in the brake motor's supply current when the pad comes into contact with the disc. The controller then checks if the contact position has changed relative to the previously stored contact position. If so, the controller establishes a new starting position, moving back relative to the new contact position, thus defining the desired clearance between the pad and the disc.On the other hand, in case of failure to detect contact, the controller receives clamping force readings from a sensor, while the pad continues to be pressed against the disc until it reaches a reference clamping force, so that the pad returns to its initial position at the moment the vehicle starts to restart the algorithm. In this way, the method of US20240246525A1 presents a complex method that depends on the detection of abrupt changes in current, with high precision, requiring frequent restarts, and should not be confused with the present invention.

[0010] US patent 12049212B2 discloses an electromechanical brake for estimating clamping force based on the brake piston position read by an angle sensor. Each piston position corresponds to a specific current consumed by the brake motor. From this, it detects... If the contact position between the disc and pad is as follows: the brake motor brings the pad closer to the disc, and from the point where these elements make contact, the motor current increases until it reaches a predefined current at a pad position further forward from the contact position. When the predefined current is reached, achieving the respective predicted pad position, this current is subtracted from a distance to find the contact point, this distance being an experimental value that depends on the brake specification. Finally, with the differences in contact position between the pad and disc, the pad wear is calculated. However, the implementation of this algorithm in US12049212B2 occurs when the vehicle is parked or when the vehicle door is open, without allowing for wear compensation during vehicle movement, unlike the present invention.

[0011] Therefore, these prior art inventions (US20240246525A1 and US12049212B2) demonstrate the dependence of the slack adjustment on reaching a specific current or force value, to the detriment of the brake response time, thus reducing braking efficiency.

[0012] Patent US10125834B2 presents an electric brake system with a controller capable of estimating brake pad wear by detecting the difference in the electric motor's rotation angle between a reference position and the final position of the linear motion mechanism, with the reference position defined by the controller. Furthermore, the US10125834B2 system has a load sensor positioned in the brake caliper that detects the axial load of the linear motion mechanism; that is, the system requires adding sensors to the brake, unlike the present invention. In addition, the US10125834B2 system only reveals the acquisition of wear data, without repositioning the brake pad to compensate for wear, and should not be confused with the present invention.

[0013] Similarly, US patent 9714687B2 deals with a device for detecting and compensating for disc brake pad wear, with compensation performed by the electric brake motor or an additional adjustment motor. To this end, a controller detects pad wear by detecting the increased stroke of the motor required to tighten the pad. However, the Adjustments based solely on the difference in engine stroke can lead to the propagation of measurement errors, affecting brake pad wear compensation and, consequently, braking efficiency.

[0014] Thus, it is still a requirement of the technique to progressively adjust the relative position between the components of the tribological pair throughout its use in order to compensate for the wear caused by friction, maintaining the response speed of the brakes, without compromising safety and vehicle handling. Ideally, this adjustment should be made by an optimized mechanical arrangement following automated algorithms, without needing to add dedicated adjustment components, since physical space is quite limited in the vehicle region where these components are located.

[0015] In the search for the state of the art in scientific and patent literature, no precedents were found that would solve all the problems of the technique detailed above. Therefore, the technique lacks a solution that allows, efficiently and with high reliability, the adjustment of the components of a tribological pair to compensate for or calibrate the spacing caused by their wear, as well as monitoring this wear and reporting it to a user or fleet manager for prediction and planning of vehicle maintenance. Summary of the invention:

[0016] Thus, the present invention solves all the problems of the prior art mentioned above. This is done by means of a solution for managing a tribological pair intended to promote braking, so that it is possible to adjust the relative position between the elements of the tribological pair, using components of the electromechanical brake itself and implementing algorithms to estimate the clamping force, compensate for wear and calibrate said position.

[0017] Like the clamping force estimator, the invention's algorithms are based on variables readily available in the brake system, eliminating the need to add sensors and electronic components to maintain efficient and safe braking for the vehicle.

[0018] In a first object, the present invention presents a process for controlling an electromechanical brake system, comprising a tribological pair disposed in a vehicle, wherein the process comprises the steps of: reading data related to a mechanical load applied by the electromechanical brake system and data related to a reference mechanical load; and adjusting the origin position of at least one of the elements of the tribological pair, based on a correlation between said data related to the applied and reference mechanical loads.

[0019] In a second object, the present invention provides an electromechanical brake system disposed in a vehicle, wherein the brake system comprises: a tribological pair, a processing unit that executes at least one algorithm for adjusting the origin position of at least one of the elements of the tribological pair, based on a correlation between data related to a mechanical load applied by the electromechanical brake system and data related to a reference mechanical load; and an electric motor of the electromechanical brake system that moves at least one of the elements of the tribological pair to the adjusted origin position.

[0020] In a third object, the present invention presents a method for defining the origin position of at least one element of a tribological pair, comprised in an electromechanical vehicle brake system, wherein the method comprises the steps of: reading data related to a reference mechanical load; applying a mechanical load, by means of an electric motor of the brake system, between elements of the tribological pair; reading data related to the applied mechanical load; indicating a relative position between elements of the tribological pair, based on a correlation between said data related to the applied and reference mechanical loads; and defining a new origin position for at least one of the elements of the tribological pair, from said relative position.

[0021] These and other objects of the invention will be immediately appreciated by those skilled in the art and will be described in detail below. Brief Description of the Figures

[0022] The following figures are presented:

[0023] Figure 1 shows a perspective view of an embodiment of the present invention applied to an electrically driven disc brake, defining the electromechanical brake system.

[0024] Figure 2 shows a perspective view of a longitudinal section of the embodiment illustrated in Figure 1, highlighting the axis of the electric motor.

[0025] Figure 3 shows a front view of the section indicated in Figure 2.

[0026] Figure 4 shows another longitudinal cross-sectional view, highlighting one of the spindles (5) driven by the motor.

[0027] Figure 5 shows a front view of the section indicated in Figure 4.

[0028] Figure 6 shows a top view of a longitudinal section of the embodiment illustrated by Figure 1, highlighting the two spindles (5).

[0029] Figure 7 shows a detailed view of the view shown in Figure 6.

[0030] Figure 8 shows the clamping force graph by spindle position, illustrating the performance of the clamping force estimation algorithm.

[0031] Figure 9 illustrates a flowchart outlining the steps of the algorithm for activating the parking brake.

[0032] Figure 10 shows an example of a flowchart outlining the steps of the auto-positioning algorithm.

[0033] Figure 11 shows a graph with test data on the self-positioning algorithm.

[0034] Figure 12 illustrates a graph indicating the clamping force before and after pad wear, as well as after pad repositioning.

[0035] Figure 13 illustrates a flowchart outlining the operational steps of the wear compensation algorithm.

[0036] Figure 14 also illustrates a sequence of operational steps for the wear compensation algorithm.

[0037] Figure 15 shows graphs indicating the performance of the compensation algorithm in adjustment.

[0038] Figure 16 shows a graph indicating the brake's performance throughout the wear test.

[0039] Figure 17 shows a graph indicating the performance of the pad position compensation algorithm in overfit.

[0040] Figure 18 shows a graph of brake performance throughout the test with the brake pad positioned with overfit. Detailed Description of the Invention

[0041] The invention aims to promote safety in driving vehicles in general, from light to heavy vehicles, by providing efficient braking throughout the lifespan of the components of each tribological pair that makes up the brake system. In this sense, the invention applies to disc or drum brake systems, focusing on electromechanical systems, but is also adaptable to pneumatic systems.

[0042] Additionally, the objects of the invention apply to vehicles under manufacture or already manufactured, such as an upgrade to the brake system, even if the vehicle does not have any pre-existing onboard sensors.

[0043] This versatility of the invention is supported by the invention's control process, which is based on variables often already available in general braking systems, without requiring the addition of complex sensors dedicated to monitoring wear, for example. Based on this common concept among the objects of the invention, this work addresses the different functionalities present in the electromechanical braking system:

[0044] i) estimation of a mechanical load applied by the electromechanical braking system;

[0045] ii) self-positioning of the electromechanical brake system;

[0046] iii) compensation for wear and over-adjustment of the electromechanical brake system; and

[0047] iv) braking acting either as a service brake or as a parking brake.

[0048] In one embodiment, the electromechanical brake system has an electric motor that receives a brake actuation signal to move one of the tribological pair elements toward the other. In a further embodiment, the tribological pair is a brake pad plus a brake disc.

[0049] This results in natural wear due to friction between the brake pad and the brake disc, requiring compensation for wear by repositioning the pad, for example. Alternatively, the brake disc can be repositioned. Furthermore, during pad installation or maintenance of other brake components, proper initial positioning of the pad and / or brake disc is necessary so that subsequent adjustments are made correctly, optimizing efficiency and preventing degrading effects such as drag.

[0050] Thus, these methods of positioning and repositioning the brake pad and / or disc, along with the estimation of the load applied by the brake, form the basis for the precise and efficient behavior of the brake of the invention, providing the functions of service brake and parking brake.

[0051] Based on this, the present invention presents a process for controlling an electromechanical brake system having the following steps: reading data related to a mechanical load applied by the electromechanical brake system and data related to a reference mechanical load; and adjusting the origin position of at least one of the elements of the tribological pair, based on a correlation between said data related to the applied and reference mechanical loads.

[0052] For the purposes of the present invention, the data related to the applied mechanical load is real and provided by an electronic component connected to the electric motor, such as a frequency inverter. In one embodiment, the data related to the applied mechanical load refers to dynamic data of the electric motor, for example, speed and torque. In another embodiment, the data related to the mechanical load refers to specifications of the electric motor, for example, model, electrical power, nominal voltage and current, etc. From the data related to the applied mechanical load (e.g., torque on the motor shaft) and a known equation, the actual clamping force applied by the brake caliper on the brake pad against the brake disc is obtained.

[0053] With respect to the data related to the reference load, reading this data contributes to an estimate of the reference load. For the purposes of the present invention, the estimate provides a torque or clamping force value. In a In this embodiment, the reference load estimate is calculated as a function of the motor's position, based, for example, on its encoder. In an embodiment of the electromechanical brake system having a spindle to move the brake pad, the reference load estimate is a function of the spindle's position relative to the motor's position.

[0054] Alternatively or redundantly, the reference mechanical load value is obtained by direct association with the data read related to the reference mechanical load. In one embodiment, the data related to the reference mechanical load is relative to the brake pedal travel. In this embodiment, the reference mechanical load is expected and linked to the brake pedal travel. In one embodiment, the pedal travel is given as a percentage. Thus, in one embodiment, the torque or clamping force values ​​correspond to specific levels of the pedal travel, these correspondences being tabulated or calculated using a function.

[0055] Alternatively, in one embodiment, the data related to the applied and reference mechanical loads refers to analog data, that is, "raw" data, without filtering or processing, such as current and voltage signals, etc. In yet another embodiment, the data related to the applied and reference mechanical loads refers to digital data or data that has undergone a transformation to indicate, for example, brake activation or deactivation (on / off), engine start or ignition, etc.

[0056] Furthermore, the reference load data is a brake activation signal indicating a required clamping force. In one embodiment, the indication of the required clamping force is provided by an autonomous control or driver assistance system.

[0057] From this point, and with the brake applied, the process provides data acquisition related to the applied and reference mechanical loads. In one embodiment, the data related to the applied mechanical load is an actual torque or tightening force, while the data related to the reference mechanical load is a required / expected / estimated torque or tightening force.

[0058] Next, the process presents a correlation between the charges. Applied and reference mechanical values. In a realization, correlation is a difference between torque or clamping force values. In a realization, correlation is an equation that relates measured and expected variables involving torque or clamping force. In a realization, correlation identifies a deviation between reference load and applied load values.

[0059] For example, for a given brake pedal actuation stroke, the motor advances in position and, consequently, the spindle advances in position, from which the clamping force or torque required for that actuation stroke is calculated. If the brake system is misadjusted, the actual torque will differ from the estimated torque.

[0060] Based on this correlation, the brake system control acts to adjust the origin position of at least one of the elements of the tribological pair. In one embodiment, the control acts to adjust the origin position of the brake pad relative to the rest position. This rest position is the origin position before the adjustment.

[0061] For the purposes of the present invention, the initial position needs to be adjusted due to wear and other factors that alter the determined distance or spacing between the brake pad and disc, aiming for efficiency in the response time for the pad to approach, contact, and press against the disc to decelerate the vehicle. In one embodiment, the initial position is the position in which the pad or disc is at rest, that is, when the brake is not applied. Thus, between the initial position and the pad-disc contact position, there is a gap which is the spacing determined for safety and braking efficiency purposes.

[0062] Based on this correlation, an estimate is made of how much the original resting position needs to be adjusted. In one embodiment, this estimate is linked to the braking cycle defined between the start of the actuation and the release of the brake pedal. Thus, this adjustment estimate is a correction value calculated by multiplying the load deviation by a gain factor, determining how much of the clearance must be compensated for in each braking cycle.

[0063] Before actually performing the adjustment of the origin position, the process It provides for the confirmation of at least one predefined safety condition. Thus, in one embodiment, a safety condition is defined by maximum and minimum limit values ​​for the adjustment in each braking cycle. In a further embodiment, the adjustment is performed after the pedal is fully released (end of cycle). In another embodiment, a safety condition corresponds to the motor position remaining stable for a predefined time and / or minimum number of consecutive cycles.

[0064] When safety conditions are met, the brake pad's original position is automatically adjusted, compensating for wear. This resets the position variables, ensuring safe clearance or spacing for efficient future braking.

[0065] In this way, the invention process is implemented by software or a computer program that executes instructions and algorithms. Comparatively, the compensation algorithm is precise because it performs the spindle advance (wear compensation) or retraction (overfit compensation). Just as wear compensation is fundamental for efficient braking, overfit compensation is also necessary to prevent overheating and premature deterioration of the pad or disc, this overfit occurring due to swelling at the beginning of the pad's life. Thus, the control occurs adaptively to adjust the position in order to provide the necessary clamping force corresponding to the brake activation. For this, the invention dispenses with the high-precision sensors present in the prior art to identify current changes in order to detect the beginning of contact between the pad and disc.

[0066] Thus, this adjustment provides compensation for wear or overfitting of at least one of the elements of the tribological pair, as well as position calibration as described in more detail below. In one embodiment, the algorithms of the invention are interconnected within the same architecture.

[0067] In this sense, the present invention presents a method for defining the origin position of at least one element of a tribological pair, comprised in a vehicle braking system, wherein the method comprises The steps are: reading data related to a reference mechanical load; applying a mechanical load, using an electric motor from the brake system, between elements of the tribological pair; reading data related to the applied mechanical load; indicating a relative position between elements of the tribological pair, based on a correlation between said data related to the applied and reference mechanical loads; and defining a new origin position for at least one of the elements of the tribological pair, based on said relative position.

[0068] In one embodiment, the origin position definition method guides a self-positioning algorithm as a calibration or pre-configuration for the brake system to correctly estimate the clamping force, for example, for the wear compensation algorithm and the parking brake algorithm to function properly.

[0069] In one embodiment, the correlation between the aforementioned data related to the applied and reference mechanical loads provides an indication of the relative position. In one embodiment, the relative position is the contact position between the pad and the disc. In one embodiment, the reference load value is a torque associated with the contact point between the pad and the disc, such that when the applied load value is equal to the reference load, it indicates that the pad is initiating contact with the disc.

[0070] Additionally, like the control process, the method is implemented by a processing unit that communicates with the electric motor of the brake system. In one embodiment, this processing unit is an integral part of the brake system, or it is an onboard unit in the vehicle or an external unit to concentrate processing remotely.

[0071] For this purpose, the method is implemented through a brake system update request. In one embodiment, this request is a user input. In another embodiment, this request is obtained when the brake system identifies a newly installed component. In another embodiment, this request is obtained when the brake system identifies faults or discrepancies in the data read. In the embodiment of the input of The user can inform the processing unit that there has been a brake pad replacement, brake system maintenance, etc. In one embodiment, the request can be scheduled with a specific frequency or configured to be executed after a certain number of vehicle engine starts or ignitions.

[0072] Furthermore, the new origin position is related to wear information for the tribological pair element. In one implementation, the wear information is sent to a remote server for fleet management, preventive and corrective maintenance management, and other traffic and safety management systems.

[0073] The process and method described above are implemented in an electromechanical brake system of the invention. The brake system arranged in a vehicle has: a tribological pair, a processing unit that executes at least one algorithm for adjusting the origin position of at least one of the elements of the tribological pair, based on a correlation between data related to a mechanical load applied by the electromechanical brake system and data related to a reference mechanical load; and an electric motor of the electromechanical brake system that moves at least one of the elements of the tribological pair to the adjusted origin position. In one embodiment, the brake system is a disc brake. In another embodiment, the brake system is a drum brake.

[0074] For the execution of compensation algorithms, self-positioning (calibration), and a parking brake that has the same mechanism as the service brake, the electric motor moves the tribological pair element by means of the advance and return of at least one spindle. For the purposes of the present invention, this spindle is self-locking or self-blocking.

[0075] Furthermore, the processing unit is an electronic component for receiving and processing data, providing commands to actuators, and information to other devices through the execution of instructions and algorithms. Thus, in one embodiment, the processing unit is capable of estimating and / or accessing data related to the reference mechanical load. In one embodiment, the processing unit accesses the mechanical load of... A reference stored in a data storage device, for example, a memory.

[0076] In one embodiment, the tribological pair of the present invention is at least one of the following: brake pad and brake disc; brake drum and brake lining; or brake shoe and railway wheel.

[0077] The examples shown here are intended only to illustrate one of the numerous ways of carrying out the invention, without limiting its scope. Example 1 - Monitoring and Maintaining the Spacing Between a Brake Pad Driven by an Electric Motor and a Brake Disc

[0078] The present invention comprises at least one device (3) that promotes forward and backward movements of a first element (1) of the tribological pair in relation to the second element (2) of the tribological pair. According to the aforementioned embodiments, the element of the tribological pair that requires more frequent maintenance is preferably the element moved by the device (3), that is, the first element (1) of the tribological pair is preferably a brake pad or a brake lining or a brake shoe, while, respectively, the second element (2) of the tribological pair is preferably a brake disc, a brake drum or a railway wheel.

[0079] These embodiments are preferentially made because the pellet moved by the device (3) is the smaller and lighter element of the tribological pair, requiring a smaller device (3) and, consequently, a lower cost and more easily arranged in the available space. It should be noted that this arrangement can be reversed, so that the larger element of the tribological pair is associated with the device (3), without any detriment to the solution proposed by the present invention.

[0080] The forward movement of the first element (1) of the tribological pair promoted by the device (3) occurs when braking is activated, in order to promote contact between the first element (1) of the tribological pair and the second element (2) of the tribological pair. Consequently, the backward movement of the first element (1) of the tribological pair promoted by the device (3) generates a spacing between the first element (1) of the tribological pair and the second element (2) of the tribological pair, occurring when the brake is in the resting position.

[0081] In one embodiment, the device (3) is at least one of: an electric motor; a hydraulic piston; a pneumatic piston; a lever; a spring; gears; screws; gear systems; or a combination of these and / or other equivalents.

[0082] The predefined spacing of the tribological pair, that is, the distance between the first element (1) of the tribological pair and the second element (2) of the tribological pair when the brake is in the rest position, is predefined in order to promote a quick start of braking after the brakes are applied, but maintaining a minimum spacing to prevent unintentional contact between the first element (1) of the tribological pair and the second element (2) of the tribological pair. The distance traveled by the first element (1) of the tribological pair during the recoil movement promoted by the device (3) corresponds to the predefined spacing. In this way, after braking ceases, the same spacing is always maintained between the first element (1) of the tribological pair and the second element (2) of the tribological pair, ensuring maintenance of the braking response time and avoiding damage to the vehicle's handling due to brake wear.

[0083] In order to measure the wear of the tribological pair and contribute to the management of its maintenance, the present invention further comprises at least one means of measuring the distance that the first element (1) of the tribological pair moves. In a preferred embodiment, the movement of the device (3) is measured and this movement is converted into the movement distance of the first element (1) of the tribological pair.

[0084] The present invention comprises a processing unit that receives movement data from the device (3) and converts it into wear data of the first element (1) of the tribological pair, storing and / or displaying it to at least one user of the system. The processing unit is also responsible for controlling the movement of the device (3), sending forward and backward movement signals, depending on the signal of brake actuation received from the vehicle driver and / or control parameters for autonomous vehicles, but also as a function of the movement data it receives from the device (3).

[0085] Thus, a major advantage of the present invention is the possibility of eliminating supplementary clearance adjustment devices for maintaining spacing and, consequently, compensating for wear of the tribological pair, since the device (3) itself, which moves the first element (1) of the tribological pair to actuate the brake, already maintains the spacing and, consequently, compensates for wear of the tribological pair. This is achieved through the processing unit's algorithm, which reads the received parameters and commands the device (3).

[0086] In one embodiment, the device (3) is a motor and its rotation is read and converted into linear displacement of the first element (1) of the tribological pair. Due to the fact that the first element (1) of the tribological pair wears out over time, the forward movement tends to be greater than or equal to the backward movement. However, the processing unit algorithm compensates for the backlash.

[0087] In one embodiment, the present invention comprises a calibration step, where the processing unit commands the device (3) that moves the first element (1) of the tribological pair, retracting it to the maximum retraction position and / or to the position of a new first element (1) of the tribological pair, and then the first element (1) of the tribological pair is advanced by the device (3) until it touches the second element (2) of the tribological pair. The processing unit converts the value of the total displacement of the device (3) into the linear displacement of the first element (1) of the tribological pair, subtracts the value of the predefined spacing, and thus determines the total wear of the tribological pair. Then, the first element (1) of the tribological pair is retracted by the device (3) to the predefined position, the assembly being ready to operate under a braking command.

[0088] In one embodiment, where the present invention is associated with a vehicle, the calibration step occurs whenever the vehicle is restarted. Thus, if any element of the tribological pair is maintained, the present The invention adapts to the new distance measurements as soon as the vehicle is restarted.

[0089] In one embodiment, the present invention comprises a predefined frequency for performing the calibration step. In this embodiment, the calibration is performed with the vehicle stationary. Furthermore, the wear compensation algorithm occurs during vehicle operation, without compromising vehicle safety and handling.

[0090] The parameters provided by the processing unit of the present invention enable the management of wear on the tribological pair elements. These parameters can be sent, stored, and processed in the cloud and / or in the vehicle itself. The wear level values ​​of the tribological pair can be displayed directly on the vehicle's dashboard and / or on a remote device, such as a smartphone, tablet, or equivalent device, and / or accessed in person or remotely via a computer.

[0091] In one embodiment, the present invention is associated with a traffic management platform, enabling the monitoring of multiple tribological pairs of the same vehicle and / or multiple vehicles. Thus, it is possible to predict when the vehicle will need maintenance and, consequently, schedule it.

[0092] In one embodiment, the present invention is applied to at least one of the following: a road and / or urban vehicle, such as: a semi-trailer truck; a road implement; a truck; a bus; an automobile; a motorcycle; a CVC; autonomous or driven by a driver, remotely or physically present. In another embodiment, the present invention is applied to the braking system of a railway vehicle. In yet another embodiment, the present invention is applied to the landing gear of an aircraft.

[0093] Thus, the invention allows monitoring the relative movement between the two elements of the tribological pair and recording the increase in forward movement for contact between the elements of the tribological pair, converting it into wear of the tribological pair element, in addition to compensating for wear or over-adjustment of the pad, also preserving the drivability and response time of the brakes. In a preferred embodiment, the elements of the pair In other embodiments, the tribological elements of the present invention are brake pads and brake discs. In other embodiments, the tribological elements of the present invention are brake drums and brake linings. In other embodiments, the tribological elements of the present invention are brake shoes and railway wheels.

[0094] A further advantage of the present invention is the reduction and optimization of the number of components to achieve the maintenance of the predefined spacing, allowing compensation for the wear suffered by the tribological pair, since the brake actuation device itself also promotes the maintenance of the spacing and, consequently, compensation for wear.

[0095] Thus, a major advantage of the present invention is the possibility of eliminating supplementary clearance adjustment devices for maintaining spacing and, consequently, compensating for wear of the tribological pair, since the device (3) itself, which moves the first element (1) of the tribological pair to actuate the brake, already maintains the spacing and, consequently, compensates for wear of the tribological pair. This is achieved through the processing unit's algorithm, which reads the received parameters and commands the device (3). Example 2 - Electromechanical Disc Brake System

[0096] In this example, the first element (1) of the tribological pair is a brake pad, the second element (2) of the tribological pair is a brake disc and the device (3) is an electric motor, as illustrated by figures 1 to 7.

[0097] The electric motor's output shaft is connected to a set of planetary gears (4), which drive the rotational movement of the motor shaft to a central drive gear. This gear drives two adjacent gears, one on each side, each of which rotates a threaded shaft or spindle (5) that unscrews from inside a piston. The piston is anchored to the back of a brake plate, so that unscrewing the shaft (5) causes the piston to advance, resulting in braking. To stop braking, the motor rotates in the opposite direction, threading the shaft (5) and piston again.

[0098] Brake pad wear is controlled by the forward and backward movement of the... The mechanism as a whole, driven by the motor (device (3)), with this control being driven by the algorithms of the processing unit, which controls the position of the pads.

[0099] In contrast, the previous technique assigns the function of compensating for wear on the tribological pair elements predominantly to the mechanical part, requiring an increase in the number of elements in the brake system.

[0100] Thus, through the present invention, the need for a mechanized adjuster to complement the brake drive motor itself is eliminated, since the drive motor already has the function of maintaining the spacing and, consequently, compensating for wear, linked to the algorithm of the processing unit. In addition, the fact that the processing unit measures the space between the brake pad and disc provides pad wear values ​​to determine an advantageous position relative to an initial position and to contribute to brake maintenance management. The advantageous position is in fact what dictates the maintenance of the spacing and, consequently, the compensation for wear in order to keep the pad and disc at the ideal clearance.

[0101] Thus, a major advantage of the present invention is the possibility of eliminating supplementary clearance adjustment devices for maintaining spacing and, consequently, compensating for wear of the tribological pair, since the device (3) itself, which moves the first element (1) of the tribological pair to actuate the brake, already maintains the spacing and, consequently, compensates for wear of the tribological pair. This is achieved through the processing unit's algorithm, which reads the received parameters and commands the device (3).

[0102] The following examples describe each of the four algorithms implemented by the processing unit. Example 3 - Estimation of Clamping Force

[0103] Estimating braking force using physical sensors implies significant increases in cost and complexity, involving integration with the braking system and vehicle, and the sensor's sensitivity to temperature, wear, etc. among other external factors.

[0104] For the purposes of the present invention, the estimation occurs indirectly, with high accuracy and robustness, and this estimated information is necessary for the operation of complementary algorithms of the processing unit, such as brake pad wear compensation, braking control strategies and operational diagnostics, thus being a strategic resource within the overall system architecture.

[0105] The encoder position reading or spindle advance stroke is divided into three stages as shown in Figure 8, each with an independent model: the first part is the dead zone, where the estimated force is equal to zero; the second part is the compliance zone, where the system cannot be approximated by a linear response; and the third and final part is the linear zone. Thus, the graph in Figure 8 demonstrates the high accuracy of the model that provides data superimposed on the test data. Example 4 - Parking brake

[0106] The parking brake is a feature built into the brake system mechanism itself, working through the self-locking of the screw thread that actuates the brake pads. In other words, the screw is rotated and actuates the pads, creating a prestressing action on the screw, which keeps the load engaged. The load is then released when a return movement occurs.

[0107] Following the steps indicated in Figure 9, the parking brake is engaged, causing the brake motor to advance in the braking direction until the required clamping force is reached. The advantage of this invention is that, once the parking brake is applied and the required force is exerted, there is no further energy consumption to keep the motor engaged; therefore, the brake can remain applied even with the vehicle switched off. Before switching off the engine, the processing unit provides a command for the motor to return a certain number (X) of positions to relieve the load on the transmission and engine within a clearance allowed by the mechanical elements of the mechanism. This relief ensures that no energy is consumed in the engine when the parking brake is engaged, while still maintaining the preload. of the time zone.

[0108] For this purpose, the self-locking spindle is a common system between the parking brake and the service brake. The service brake is controlled by the brake pedal, while the parking brake is controlled by the parking brake button. Although these controls and actuation methods may be different and independent, the service and parking brake systems share the same mechanism containing the spindle.

[0109] Thus, the service and parking brake controls operate in parallel, so the service brake force should be prioritized when it is greater than the parking brake force. When the service brake force is less, the parking brake is prioritized. For this to happen, the parking brake can only be released if the service brake pedal is pressed with a force greater than or equal to the parking brake force.

[0110] Additionally, the parking function, which keeps the vehicle stationary on an incline or decline, for example, an 18% slope, is adjustable for each situation with higher or lower braking demands.

[0111] Furthermore, the implementation of the parking brake algorithm is based on a clamping force estimator algorithm, that is, on a correlation between clamping force and at least one of the engine's state variables - torque, speed, and position. Thus, the clamping force for the parking brake is adjustable according to the vehicle's needs or external conditions. Example 5 - Self-adjusting of the pad position relative to the disc.

[0112] In general, when installing a brake system with brake linings or pads, adjustment is necessary, commonly performed manually on the brake mechanism. These adjustments aim to determine the correct clearance, but depend on the operator's correct execution, making it difficult to standardize clearances across different brakes in the vehicle. This can lead to differences in brake wear and unbalanced braking.

[0113] For the purposes of the present invention, self-tuning or adjustment (in English, tuning) Self-adjustment is a feature provided during the initialization of the brake system, for example, when starting the vehicle, aiming to maintain the predefined spacing between the brake pad and disc to promote driving safety and brake performance throughout its lifespan. From this, self-adjustment is a brake calibration that repositions the pads, adjusting the aforementioned spacing. Therefore, self-adjustment offers several functionalities to compensate for differences in thickness caused by wear, pad replacement, and / or dimensional changes generated by swelling and increased thickness due to heating of the friction material.

[0114] For example, the expected spacing between the disc and each pad is 1 mm. Figure 10 shows a flowchart for the automatic positioning of the pad, starting from the initialization of the brake system or another indication for automatic positioning, for example, pad replacement. Thus, the motor advances the spindle in position increments, reading and filtering torque information from the motor. When the torque corresponds to a force equal to another reference force, which refers to the contact between the disc and pad (e.g., 3 Nm), the motor returns a certain number of positions. For example, a 1 mm offset is equivalent to 127,000 motor positions in this example. Finally, the function's state variables are reset, such as updating the initial position of the pad when it is 1 mm away from the disc. If there is a variation in the recorded initial position compared to the previous one, the processing unit feeds the brake wear detector.

[0115] For system validation and proof-of-concept purposes, consecutive actuations were performed under the following conditions: (i) two pedal actuations with the system calibrated, (ii) pedal actuations with approximately 0.75 mm of wear, (iii) execution of the self-positioning algorithm, (iv) pedal actuation after the execution of the self-positioning algorithm. Figure 11 shows the system response under the four test conditions, demonstrating the performance loss due to pad wear in step (ii) and the maintenance of performance in step (iv). Self-positioning, i.e., pad position calibration, occurs in step (iii), after the end of a braking cycle, where there is a small indication of clamping force and torque. when the spindle advances and returns rapidly. With this, the clamping force is observed in the initial adjusted condition and after readjustment; the clamping force graph indicates approximately the same force value for applying 100% of the brake pedal, which proves the repeatability of the invention's algorithm.

[0116] Furthermore, in Figure 12, it is possible to observe the correlation between the spindle position and the clamping force, confirming that the self-positioning algorithm is able to maintain the spacing at 1 mm, validating the relationship between position, torque and force, and thus proving the algorithm's performance. Example 6 - Brake Wear Compensation

[0117] Wear compensation in heavy vehicle brake systems is essential to maintain braking efficiency, reduce manual maintenance, and ensure safety, even after prolonged use of components (especially brake linings and pads).

[0118] Disc or drum brake systems have friction materials that wear out with use. In the case of disc brake systems, such as electromechanical brakes, the friction element is the brake pad, which, upon contact with the disc, decelerates the vehicle, but also loses its thickness over time (wear).

[0119] Instead of purely mechanical structures seen in the prior art, mainly in pneumatic brake systems, but also in electromechanical ones, the example of the invention addresses an algorithm for wear compensation by means of a clamping force estimator, position reading and pedal actuation.

[0120] In general, wear compensation is an algorithm that dynamically executes the self-positioning algorithm itself, as illustrated in the flowchart in Figure 13. The compensation algorithm acts by correcting the actuator's origin position based on a contact detection algorithm. When the system detects consistent deviations in the mechanical contact's starting position (relative position), the system applies incremental compensations to the origin position.

[0121] Thus, starting from the actuator's point of origin, the system is Continuously recalibrated to reflect the mechanical reality of the assembly. The main benefit of this approach is that it maintains a constant advance distance required to achieve the desired clamping force, ensuring accuracy in the final force value, a uniform response time, and predictable transient behavior throughout the system's lifespan.

[0122] Furthermore, this source correction strategy makes the system more robust to variations in mechanical conditions and improves performance consistency across different operating cycles, reducing the need for retraining, fine-tuning of the controller, or new parameter settings.

[0123] The algorithm's implementation is based on continuously monitoring the brake pedal actuation cycles and robustly detecting the initial contact position between the actuator and the braking mechanism. Based on this position, an error is calculated relative to a nominal contact reference, and incremental compensation is applied at the actuator origin, provided certain stability and safety conditions are met.

[0124] The algorithm initiates its logic whenever the brake pedal is pressed, monitoring the system's response to detect the moment of mechanical contact between the components. This detection occurs when the torque sensor indicates a value below a fixed threshold, representing that the actuator encountered significant resistance and considering a negative value for the measured torque. To avoid false readings, this verification is only considered valid if the system has remained with the pedal completely released for a minimum interval, ensuring that it is a new braking cycle. At this moment, the system records the position where the contact occurred and calculates the deviation from an ideal reference position, which represents the desired clearance between the components in good condition.

[0125] Based on this deviation, an estimate is made of how much the origin of the current position needs to be adjusted. The calculated correction value is obtained by multiplying the error by a gain factor, which determines how much of the slack must be compensated for in each cycle. To ensure the robustness of the system, the application of this correction is limited by safety and measurement quality criteria. Only corrections larger than a minimum level are accepted, preventing small fluctuations from causing changes; similarly, there is a maximum limit per correction, ensuring that abrupt changes are not applied improperly.

[0126] Even after detecting wear and calculating how much the source needs to be adjusted, the adjustment is not applied immediately. The system waits until the pedal is fully released and the actuator position remains stable for a minimum number of consecutive cycles, ensuring there are no residual movements in the system. This prevents the adjustment from occurring during transients or vibrations.

[0127] When all the previous conditions are met, the system applies compensation to the actuator's position reference. This means the entire control logic considers a new, corrected origin, ensuring that the future contact point remains within the desired operating range. This mechanism allows the system to maintain both performance and response time throughout the mechanism's lifespan, without the need for manual recalibration.

[0128] For illustrative purposes, Figure 14 shows the algorithm for this example with fictitious values ​​in 6 steps. In step 1, the brake is in its initial condition, with the correct pad-to-disc spacing. In step 2, the 1st step occurs. o Braking cycle, considering 100% pedal application, in which the system satisfactorily achieves the described parameters (e.g., torque exerted by the motor), resulting in an estimated force equal to the actual force.

[0129] After braking, the system was worn, as shown in step 3. In 2 oDuring the braking cycle (steps 4 and 5), the brake is applied again at 100% pedal pressure. However, in this case, the required torque value was lower than the ideal torque for that motor advance position (i.e., encoder). This is also verified by the actual force measurement being lower than the estimated force measurement. Because the algorithm works by monitoring these variables and checking satisfaction levels in real time, it can identify that the 2 o The cycle was not satisfactory. Therefore, when the second cycle ends... o During the braking cycle, the system performs compensation at the braking point in step 6. Starting point or origin position, in order to find the correct spacing between the pad and the disc.

[0130] Therefore, the algorithm was developed based on heuristic logic, given the low linearity but high repeatability of the system. To test the algorithm, a wear simulation device was developed as a validation and proof of concept of the invention, using load cells mounted on the brake system to monitor the actual clamping force compared to the estimated force.

[0131] Therefore, tests were carried out where the system was subjected to wear and adjustments, generating the need for the algorithm to correct the position by advancing or retracting the spindles. In the first test, illustrated in Figure 15, it is possible to observe that, between 50 and 55 seconds, there was simulated wear and around 74 seconds of testing, the algorithm corrected the original position, maintaining the required clamping force with spindle advancement.

[0132] To verify the relationship between spindle position and clamping force, Figure 16 illustrates the dispersion of measurements across the three braking cycles performed in the wear test. The blue dots (dispersion furthest to the left) represent the first braking cycle, the orange dots represent the second braking cycle (when the system is worn), and the yellow dots (dispersion furthest to the right) represent the third braking cycle. It is evident that the force response per spindle position was readjusted between the second and third cycles, which proves the functioning of the wear compensation algorithm.

[0133] Furthermore, the invention allows for overfit compensation. This effect arises from problems in the mechanisms or from variations in the thickness of the brake pads, which can expand, especially at the beginning of their use. Therefore, the functionality of the algorithm that provides adjustment, compensating for wear and / or overfit effects, is fundamental to avoiding brake performance losses and drag effects, respectively.

[0134] Thus, Figure 17 shows an overfit test, where it is possible to observe the spindle retraction (approximately at 116 and 123 s), due to the excessive force detected in the preceding braking cycles.

[0135] Furthermore, Figure 18 shows the relationship between spindle position and clamping force, indicating the dispersion of measurements across the five braking cycles performed in the overfit test. With the execution of the algorithm, it can be observed that after a few braking cycles, following the overfit, the relationship between force and spindle position was normalized, which can be seen in the practically overlapping blue and green points.

[0136] Those skilled in the art will appreciate the knowledge presented here and will be able to reproduce the invention in the forms presented and in other variants and alternatives, covered by the scope of the following claims.

Claims

Claims 1. Control process for an electromechanical brake system, comprising a tribological pair installed in a vehicle, characterized by comprising the steps of: a. reading data related to a mechanical load applied by the electromechanical brake system and data related to a reference mechanical load; and b. adjusting the origin position of at least one of the elements of the tribological pair, based on a correlation between said data related to the applied and reference mechanical loads.

2. Process, according to claim 1, characterized by the adjustment step providing a position calibration and / or a wear compensation or overfit of at least one of the elements of the tribological pair.

3. Process, according to claim 1, characterized in that the reading step comprises an estimate of the reference mechanical load.

4. Process, according to claim 1, characterized in that the reference mechanical load is an expected mechanical load associated with the data read in relation to the reference mechanical load.

5. Process, according to claim 1, characterized in that the reference mechanical load data is relative to the brake pedal travel.

6. Process, according to claim 1, characterized in that the adjustment step occurs after confirmation of a predefined safety condition.

7. Electromechanical braking system comprising a tribological pair, arranged in a vehicle, characterized by comprising: a. a processing unit that executes at least one algorithm for adjusting the origin position of at least one of the elements of the tribological pair, based on a correlation between data related to a mechanical load applied by the electromechanical braking system and data related to a reference mechanical load; and b. an electric motor of the electromechanical brake system that moves at least one of the elements of the tribological pair to the adjusted origin position.

8. Brake system, according to claim 7, characterized in that the reference mechanical load data is relative to the brake pedal travel.

9. Braking system, according to claim 7, characterized in that the electric motor moves the tribological pair element by means of the advance and return of at least one spindle.

10. Brake system according to claim 9, characterized by providing the functions of parking brake and service brake by means of said spindle.

11. Brake system, according to claim 7, characterized in that the processing unit estimates and / or accesses data related to the reference mechanical load.

12. Method for defining the origin position of at least one element of a tribological pair, comprised in an electromechanical vehicle braking system, characterized by comprising the following steps: a. reading data related to a reference mechanical load; b. applying a mechanical load, by means of an electric motor of the braking system, between elements of the tribological pair; c. reading data related to the applied mechanical load; d. indicating a relative position between elements of the tribological pair, based on a correlation between said data related to the applied and reference mechanical loads; and e. defining a new origin position for at least one of the elements of the tribological pair, from said relative position.

13. Method, according to claim 12, characterized by being implemented by a processing unit, communicating with the electric motor of the brake system, through a brake system update request.

14. Method, according to claim 12, characterized in that the new origin position is related to wear information of the tribological pair element.

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