JP2022514543A - Methods for driving automated parking brakes and corresponding equipment - Google Patents

Abstract

The present invention is a method for driving an automated parking brake (13) for an automobile, comprising an electric actuator (2) for setting a predetermined tightening force, at least: said electric. It includes a step of calculating the inertial rotation of the actuator (2) of the equation and a step of setting the predetermined tightening force in consideration of the calculated inertial rotation of the electric actuator (2). Regarding the method. Further, the present invention relates to usage of this method, as well as devices (1, 9, 13, 15) designed to carry out this method. [Selection diagram] FIGS. 1 and 4

Description

The present invention relates to a method for driving an automated parking brake for an automobile, which comprises an electric actuator for setting a predetermined tightening force, the method of which is at least
・ Steps to calculate the inertial rotation of the electric actuator,
-Contains a step of setting a predetermined tightening force in consideration of the calculated inertial rotation of the electric actuator. Further, the present invention relates to usage of this method, as well as devices designed to carry out this method.

From the prior art, for example, electromechanical parking brakes are known. The system has, for example, an electromechanical regulator on the wheel brake. Torque is generated via the motor, and this torque is further converted into tightening force via the transmission unit and the spindle unit. The current of the motor is measured during the operation of the parking brake. The current of the motor is directly proportional to the tightening force obtained. When the current required for the desired tightening force is obtained, the motor is braked to a stop state via a short circuit. During this time, motor voltage and motor current cannot be measured (according to the provisions of VDA305-100). Despite the braking of the motor, the tightening force is further increased by switching off the motor depending on the already obtained tightening force.

On the other hand, preferably, the method according to the present invention can accurately set a desired tightening force. In particular, this method allows the small braking force and preliminary position adjustment of the brake to be uniformly and well set via temperature and voltage changes.

This is possible by the features described in the independent claims in accordance with the present invention. Other embodiments of the invention are subject to the dependent claims.

The method according to the invention for driving an automated parking brake for an automobile, which has an electric actuator for setting a predetermined tightening force, is at least
・ Steps to calculate the inertial rotation of the electric actuator,
It includes a step of setting a predetermined tightening force in consideration of the calculated inertial rotation of the electric actuator.

The setting of a predetermined tightening force should be interpreted in particular as the formation of a predetermined tightening force. In this sense, this method can be used, for example, to obtain a predetermined braking force, especially during the closing process of the parking brake. The term coasting rotation (also called switch-off) should be interpreted as the coasting of the electric actuator (motor) of the parking brake during braking. Braking is performed until stop, especially due to a short circuit. This should also be interpreted as inertial rotation distance or coasting distance. In this method, inertial rotation is calculated or calculated or estimated, and this inertial rotation is set when braking is initiated at the current time point, for example by a short circuit. The inertial rotation thus calculated is taken into account in order to capture the desired tightening force-after the inertial rotation-as accurately as possible and thereby set it in the system at the start of the actual braking.

The present invention allows the calculation of a predicted further increase in tightening force due to inertial rotation. This makes it possible to obtain a prediction about the tightening force actually provided during the tightening force formation. This is particularly advantageous when providing a small tightening force step, for example in brake tester mode, or in mechanical deceleration (IFA). This allows the motor to be shut off reasonably early.

In addition, the mileage during braking is calculated, thereby relatively high accuracy when setting a shortened tightening stroke, for example when adjusting the preliminary position of the actuator for HAP operation (High Autonomous Parking "Highly Autonomous Parking"). Is obtained.

The damped motor may be interpreted as a damped spring mass system. The first energy accumulator is, for example, a rotating mover. Another energy accumulator is, for example, a brake caliper having a spring constant proportional to stiffness. Damping is determined by motor resistance. The initial state of this system is obtained from the number of revolutions of the motor at the beginning of the braking short circuit. The number of revolutions to decrease is calculated and integrated into the piston stroke. This piston stroke can be converted into a tightening force via the stiffness of the system. If this prediction is taken into account when forming the tightening force, a desired tightening force with high accuracy can be set.

In a preferred embodiment of this method, this method further
・ Step to calculate the tightening force increase due to inertial rotation,
A step of calculating the time point for stopping the operation of the electric actuator in order to obtain a predetermined tightening force after the end of inertial rotation.
Contains at least one step of the above.

This is interpreted as the calculation or at least estimation of the tightening force increase obtained based on the inertial rotation of the motor during braking or obtained during the inertial rotation. This tightening force increase can be calculated, for example, by the calculated inertial rotation stroke and by the stiffness of the brake caliper.

The actuation should be interpreted as the active control of the electric actuator. The opposite of this should be interpreted as an outage. Shutdown should be interpreted, for example, as the end of control. Further, stoppage of operation should be interpreted as braking, especially by applying a short circuit, especially until the stop of an electric actuator.

In a possible embodiment of this method, during the operation of the electric actuator of the parking brake, i.e., during the operation of the parking brake, especially during the tightening process of the parking brake.
・ Step to calculate the inertial rotation of the electric actuator,
・ Step to calculate the tightening force increase due to inertial rotation,
A step to calculate when the electric actuator is deactivated to set a given tightening force following inertial rotation,
At least one of these steps is performed.

In a preferred embodiment of this method, the actuation of the electric actuator is stopped before the predetermined tightening force is obtained.

This means that the control of the motor is already terminated before the desired tightening force is actually obtained. The formation of the final tightening force, that is, the setting of the predetermined tightening force is performed only at the end of the inertial rotation of the motor.

In a selective evolution of this method, the deactivation of the electric actuator is performed so that a predetermined tightening force is obtained based on the inertial rotation of the electric actuator.

This means that the set tightening force increase is estimated based on the calculated inertial rotation. For this purpose, for example, a spring constant proportional to the calculated stiffness of the brake caliper can be used. Braking of the electric actuator due to a short circuit is done in a manner that allows the inertial rotation to increase the tightening force required at this point.

In a preferred embodiment of this method, a time point for stopping the operation of the electric actuator is calculated, in which case a predetermined tightening force is set after the inertial rotation of the electric actuator. It has been decided to be done.

This is done at some point during the outage, thereby based on the general technical characteristics of the system (especially motor resistance, motor constants and brake caliper rigidity), as well as the latest status of the system (especially of the motor). The desired tightening force is set at the end of the obtained coasting rotation, taking into account the latest rotation speed, the position of the parking brake).

In a possible embodiment of this method, the tightening force increase is calculated based on the calculated inertial rotation. This means that the inertial rotation that is imminent in the current shutdown of the electric actuator will calculate the future tightening force increase.

A preferred development of this method is to calculate the tightening force increase due to the inertial rotation of the electric actuator.
・ Motor resistance,
・ Motor constant,
・ Brake caliper rigidity,
・ Idling current,
It is done in consideration of at least one of the factors of.

The calculated parameters can preferably be used when calculating the inertial rotation of the electric actuator or when calculating the tightening force increase due to the inertial rotation.

In a selective embodiment of this method, the calculation of motor resistance is performed by evaluating the current and / or voltage values during the parking brake switch-on process. In a possible embodiment of this method, the calculation of motor constants is performed by evaluating current and / or voltage values during the parking brake switch-on process. In a preferred development of this method, the calculation of brake caliper stiffness is performed during the parking brake tightening process.

In a selective embodiment of this method, a plurality of predetermined tightening force steps are set during the parking brake tightening process.

This means that not only a predetermined tightening force is set during the parking brake process, but a plurality of different tightening forces are set. Especially in this case, the plurality of tightening force stages are set at gradually increasing heights. For example, first 10% of the maximum force, then 20% of the maximum force, and finally the maximum force are set. This type of tightening force step setting is also referred to as an "Independent Force Application (IFA)" incremental force application ". Preferably, such a method allows decelerated braking force generation. Is particularly suitable for decelerating the vehicle with the parking brake, especially from higher speeds. Such a method can also be used when the vehicle is on the brake tester.

In a preferred embodiment of this method, it is calculated whether the vehicle is in the brake tester. In a selective embodiment of this method, it is calculated whether the vehicle is being decelerated by the parking brake. For example, it is checked whether the parking brake switch has been manually operated while driving.

Further, according to the present invention, the usage of the above method is intended, and this usage is described.
・ Situation when the vehicle is in brake tester mode,
・ Situations when the vehicle is decelerated by the parking brake,
Intended in at least one of these situations.

Further, according to the proposal presented herein, a device is provided, which is configured to perform, control or perform the steps of the modified examples of the methods presented herein on a suitable device. .. The embodiment of changing the shape of the apparatus according to the present invention can also solve the problem underlying the present invention quickly and effectively.

The device may be interpreted herein as an electrical device that processes a sensor signal and depends on the sensor signal to control and / or output a data signal. The device may have an interface, which may be configured hardware and / or software. In a hardware configuration, the interface may be, for example, part of a so-called system ASIC that contains various functions of the device. However, the interface may be a unique integrated circuit or at least partially composed of discrete elements. In a software configuration, the interface may be, for example, a software module provided alongside other software modules on a microcontroller. As the device, a braking device and / or a control unit and / or an electromechanical parking brake and / or a braking device are particularly understood.

Any one of the above embodiments, which may be stored in a machine readable carrier or storage medium, such as a semiconductor storage device, hard disk space or optical storage device, particularly when a program product or program is run on a computer or device. Computer program products or computer programs that have program code used to perform, execute, and / or control the steps of the method according to are also advantageous.

It is a side view of a braking device equipped with an automatic "motor-on caliper" structural type parking brake. It is an equivalent circuit diagram for a braked motor. It is a figure which shows the voltage change at the time of inertial rotation of a motor. It is a schematic diagram of the method implementation.

It should be noted that the features individually described herein may be combined with each other in any technically significant form and disclose another embodiment of the invention. Other features and effectiveness of the invention can be obtained from the description of the plurality of examples with reference to the accompanying drawings.

FIG. 1 shows a schematic cross-sectional view of the brake device 1 for a vehicle. In this case, the braking device 1 has an automated parking brake 13 (automatic parking brake, electromechanical parking brake or automated parking brake, also abbreviated as APB). The parking brake can apply a tightening force for fixing the vehicle by an electromechanical actuator 2 (electric motor). For this purpose, the electromechanical actuator 2 of the parking brake 13 shown in the figure drives a spindle 3 supported in the axial direction, particularly a threaded spindle. The spindle 3 is provided with a spindle nut 4 at an end opposite to the actuator 2, and the spindle nut 4 abuts on the brake piston 5 in a tightened state of the automated parking brake 13. In this manner, the parking brake 13 transmits the force to the brake linings 8, 8'or the brake disc 7. In this case, the spindle nut abuts on the inner end face of the brake piston 5 (also referred to as the bottom of the brake piston or the rear side of the bottom of the inner piston). The spindle nut 4 is moved in the axial direction during the rotational movement of the actuator 2 and the rotational movement of the spindle 3 generated as a result. The spindle nut 4 and the brake piston 5 are supported in a brake caliper 6 that grips the brake disc 7 in a pliers shape, and the brake piston 5 is sealed with respect to the periphery by a piston seal ring 12.

The automated parking brake 13 is configured as shown, for example, as a "motor-on caliper" system and is combined with the foot brake 14. The footbrake 14 is configured as a hydraulic system in FIG. 1, where the hydraulic actuator 10 is an ESP pump or electromechanical brake booster (eg, "Bosch iBosch" "Bosch, electrohydraulic". It can be assisted or performed by a booster "). Another embodiment of the actuator 10, such as the so-called IPB (Integrated Power Break "Integrated Power Brake"), is also conceivable.

The control of the brake actuators 2 and 10 is performed by a single or a plurality of outputs, that is, the control unit 9. The control unit 9 may be, for example, a control unit of a vehicle dynamic system such as an electronic stability program (ESP) or another control unit. The vehicle braking system 15 comprises at least one braking device 1, consisting of a foot brake and an electric parking brake for braking one wheel, preferably a foot brake for braking four wheels and two wheels. Includes two parking brakes for braking.

FIG. 2 shows an electrical equivalent circuit diagram for a damped motor. From this electrical equivalent circuit diagram, it is possible to derive the current change and voltage change of the motor during braking with an increasing load. During the switch-on peak, the motor resistance _RM and the motor constant _KM are determined. The stiffness Stiff of the brake caliper is calculated during the immediately preceding tightening process. It is assumed that the inertial mass J, the gear ratio V _Gear , the transmission efficiency η, and the spindle pitch SpPitch are known. _IL is the load current of the motor at the start of braking. From this equivalent circuit diagram, a differential equation for the generator-type voltage u of the motor to be switched off is derived.

The voltage change u of the system is obtained from the solution of Equation 1 as an attenuated vibration supplemented only by the component of the load current.

U ₀ is the initial voltage (proportional to the initial rotation speed). The time constant τ and the angular frequency ω are calculated as follows.

Typical values are approximately 10 ... 20 ms for τ and approximately 10s ^-1 for ω (eg f = 1.5 Hz). Therefore, the influence of the time constant is predominant and the cosine may be ignored (other details are given in the description of FIG. 3).

FIG. 3 shows a generator-like voltage change during inertial rotation of a motor. The illustrated voltage change u is calculated as follows.
-(1) u_num, (solid line), numerical solution- (2) u_solv2, (dashed line)
-(3) u_solvv1, (dashed line)
The initial values are u0 = 14.3V and IL = 0.7A. The step width of u_num is 100 μs. The smaller the step width, the closer (1) to (2).

Since u = _{KM ω can be said to be the angular frequency ω M of} the rotating motor,

The remaining spindle strokes s are obtained via the integral of ω _M.

to _off is the time until the motor is switched off. This is calculated as u = 0 in the above [Equation 5].

Thereby, the stroke can be easily calculated from [Equation 7] and [Equation 8].

As a result, an additional tightening force dF _cl during braking can be obtained.

FIG. 4 shows a diagram of the method steps of an embodiment of the present invention. In this case, the method is started in the first step S1. Next, the necessary parameters are calculated in step S2. These parameters are, for example, motor resistance, motor constants and / or brake caliper stiffness. In step S3, the coasting distance, that is, the inertial rotation of the motor is calculated. Based on this, in step S4, the tightening force increase due to this coasting distance is calculated. The stiffness of the brake caliper may also be considered for the calculation. By calculating the tightening force increase, an estimate of the future increase in the latest tightening force generated based on the inertial rotation of the motor in case the motor should be braked by a short circuit at the latest point in time. Or the operation can be obtained. In step S5, the control and braking of the motor is actually cut off in order to set the desired tightening force with the parking brake after the motor coasts. Step S6 indicates the end of this method.

1 Brake device 2 Actuator 3 Spindle 4 Spindle nut 5 Brake piston 6 Brake caliper 7 Brake disc _8,8'Brake lining 9 Control unit 10 Brake actuator 12 Piston seal ring 13 Parking brake 14 Foot brake 15 Brake system IL At the start of braking Motor load current J Inertial mass KM Motor constant _RM Motor resistance S1, S2, S3, S4, S5, S6 Step Stiff Brake caliper rigidity _SpPitch Spindle pitch to _off Time until the motor is switched off u Voltage, voltage change U ₀ initial voltage V _Gear gear ratio τ time constant η transmission efficiency ω angular frequency ω _M motor angular frequency

Claims (13)

In a method for driving an automated parking brake (13) for an automobile, which has an electric actuator (2) for setting a predetermined tightening force.
The above method is at least
-The step of calculating the inertial rotation of the electric actuator (2) and
A step of setting the predetermined tightening force in consideration of the calculated inertial rotation of the electric actuator (2), and
A method for driving an automated parking brake (13), which comprises. The above method further
・ Step to calculate the tightening force increase due to inertial rotation,
A step of calculating the time point at which the electric actuator (2) is stopped in order to obtain a predetermined tightening force after the end of inertial rotation.
The method of claim 1, wherein the method comprises at least one of the steps. The method according to claim 1 or 2, wherein the operation of the electric actuator (2) is stopped before the predetermined tightening force is obtained. Any one of claims 1 to 3 for stopping the operation of the electric actuator (2) so that the predetermined tightening force is obtained based on the inertial rotation of the electric actuator (2). The method described in the section. The time point for stopping the operation of the electric actuator (2) is calculated, and the predetermined tightening force is set at the time point after the inertial rotation of the electric actuator (2) is obtained. The method according to any one of claims 1 to 4, which is determined in 1. The method according to any one of claims 1 to 5, wherein the tightening force increase is calculated based on the calculated inertial rotation. The calculation of the tightening force increase due to the inertial rotation of the electric actuator (2) is performed.
・ Motor resistance ( _RM ),
・ Motor constant ( _KM ),
・ Brake caliper rigidity (Stiff),
The method according to any one of claims 1 to 6, wherein at least one of the idling current factors is taken into consideration. The method of claim 7, wherein the motor resistance ( _RM ) is calculated by evaluating a current value and / or a voltage value during the switch-on process of the parking brake (13). The method of claim 7, wherein the motor constant ( _KM ) is calculated by evaluating a current value and / or a voltage value during the switch-on process of the parking brake (13). The method according to claim 7, wherein the calculation of the brake caliper rigidity (Stiff) is performed during the tightening process of the parking brake (13). The method according to any one of claims 1 to 10, wherein a plurality of predetermined tightening force steps are set during the tightening process of the parking brake (13). In the usage of the method according to any one of claims 1 to 11.
・ Situation when the vehicle is in brake tester mode,
-The situation when the vehicle is decelerated by the parking brake (13),
The usage of the method according to any one of claims 1 to 11 in at least one of the situations. An apparatus designed to perform the method according to any one of claims 1 to 11 (1, 9, 13, 15).

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