CN114954380A - Line control brake pedal feeling simulator with variable feeling - Google Patents

Line control brake pedal feeling simulator with variable feeling Download PDF

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Publication number
CN114954380A
CN114954380A CN202210560440.7A CN202210560440A CN114954380A CN 114954380 A CN114954380 A CN 114954380A CN 202210560440 A CN202210560440 A CN 202210560440A CN 114954380 A CN114954380 A CN 114954380A
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China
Prior art keywords
pedal
piston
reaction force
force value
brake
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CN202210560440.7A
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Chinese (zh)
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CN114954380B (en
Inventor
李静
杜康
王志伟
刘学亮
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Yanshan University
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Yanshan University
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T7/00—Brake-action initiating means
    • B60T7/02—Brake-action initiating means for personal initiation
    • B60T7/04—Brake-action initiating means for personal initiation foot actuated
    • B60T7/06—Disposition of pedal
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
    • B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
    • B60T8/40—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition comprising an additional fluid circuit including fluid pressurising means for modifying the pressure of the braking fluid, e.g. including wheel driven pumps for detecting a speed condition, or pumps which are controlled by means independent of the braking system
    • B60T8/4072—Systems in which a driver input signal is used as a control signal for the additional fluid circuit which is normally used for braking
    • B60T8/4081—Systems with stroke simulating devices for driver input
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
    • B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
    • B60T8/40—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition comprising an additional fluid circuit including fluid pressurising means for modifying the pressure of the braking fluid, e.g. including wheel driven pumps for detecting a speed condition, or pumps which are controlled by means independent of the braking system
    • B60T8/4072—Systems in which a driver input signal is used as a control signal for the additional fluid circuit which is normally used for braking
    • B60T8/4081—Systems with stroke simulating devices for driver input
    • B60T8/409—Systems with stroke simulating devices for driver input characterised by details of the stroke simulating device

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Regulating Braking Force (AREA)
  • Braking Elements And Transmission Devices (AREA)

Abstract

The application discloses a brake-by-wire pedal feel simulator with variable feel, and relates to the technical field of pedal feel simulators. The pedal reaction force value can be adjusted within a certain range, the defects that the traditional pedal feel simulator has single pedal feel and cannot select the pedal feel according to the change of the running working condition are overcome, and when the electric control unit fails, the pedal feel simulator still has the pedal feel simulation function by means of a mechanical structure. The pedal feel simulator comprises a pedal assembly, a brake pedal feel simulation mechanism, a power transmission mechanism, a detection unit and a control unit; the brake pedal feeling simulation mechanism comprises a cylinder body, a first piston, a second piston, a ball screw pair and a power transmission mechanism; a first elastic piece is arranged between the first piston and the second piston, the first end of the second piston is fixedly connected with the second elastic piece, a third elastic piece is arranged between the ball screw pair and the second piston, and the detection unit can detect the pedal angular displacement value and the pedal reaction value; the control unit is electrically connected with the detection unit and the power transmission mechanism.

Description

Line control brake pedal feeling simulator with variable feeling
Technical Field
The application relates to the technical field of pedal feel simulators, in particular to a pedal feel simulator with variable feel.
Background
With the development of automobile electromotion and intellectualization, more and more automobiles adopt a brake-by-wire system to replace a brake system of a traditional vacuum booster, and in the brake-by-wire system, an Electronic Control Unit (ECU) receives a signal of a pedal stroke sensor and establishes brake pressure through various different pressure building modules according to the signal.
Existing pedal feel simulators mainly include hydraulic pedal feel simulators and mechanical pedal feel simulators. Among them, the hydraulic pedal feel simulator has the disadvantages: low integration level, high required precision and the like. The disadvantages of mechanical pedal feel simulators are: once the structure is determined, the relationship between the pedal force and the pedal displacement is determined, so that the problems that the pedal feel is single, the proper pedal feel cannot be selected according to the change of the running condition and the like exist.
Disclosure of Invention
The embodiment of the application provides a brake-by-wire pedal feel simulator with variable feel, which can randomly adjust the pedal counterforce value within a certain range, overcomes the defects that the traditional pedal feel simulator has single pedal feel and cannot select proper pedal feel according to the change of running conditions, and has a pedal feel simulation function by means of a mechanical structure when an electric control unit fails.
In order to achieve the above object, an embodiment of the present application provides a variable-feel brake-by-wire pedal feel simulator, including a pedal assembly, a brake pedal feel simulation mechanism, a power transmission mechanism, a detection unit, and a control unit; the pedal assembly comprises a brake pedal and a push rod, and the first end of the push rod is hinged to the brake pedal; the brake pedal feeling simulation mechanism comprises a cylinder body, a first piston, a second piston, a ball screw pair and a power transmission mechanism; the first piston, the second piston and the ball screw pair are sequentially arranged in the cylinder body, and the first piston and the second piston can reciprocate along the axial direction of the cylinder body; the second end of the push rod is connected with the first end face of the first piston; a first elastic piece is arranged between the first piston and the second piston and can provide force for the second piston in a direction away from the first piston; the first end of the second piston is fixedly connected with a second elastic piece, the second elastic piece can provide a force in the direction away from the first piston for the second piston, and a gap is formed between the second elastic piece and the first piston when the second elastic piece is in a free state; the screw rod of the ball screw pair is rotatably connected to the bottom of the cylinder body, and the screw rod of the ball screw pair extends out of the cylinder body and then is connected with the power transmission mechanism; a third elastic piece is arranged between the ball screw pair and the second piston, and the third elastic piece can provide force for the second piston in the direction away from the ball screw pair; the detection unit is capable of detecting the pedal angular displacement value and the pedal reaction force value; the control unit is electrically connected with the detection unit and the power transmission mechanism; the control unit is configured to: receiving the pedal angular displacement value and the pedal reaction force value detected by the detection unit; calculating an expected pedal reaction force value; and judging whether the absolute value of the difference value between the pedal reaction force value detected by the detection unit and the expected pedal reaction force value is larger than a second preset value or not, if so, controlling the power transmission mechanism to start according to the magnitude relation between the pedal reaction force value detected by the detection unit and the expected pedal reaction force value so as to adjust the feeding amount of the nut in the ball screw pair until the difference value between the pedal reaction force value detected by the detection unit and the expected pedal reaction force value is smaller than or equal to the second preset value.
Further, power transmission mechanism includes driving motor and cylindrical gear pair, driving motor's output is connected the input of cylindrical gear pair, the output of cylindrical gear pair is connected the lead screw end of ball screw pair.
Further, the first elastic piece, the second elastic piece and the third elastic piece are compression springs; two ends of the first elastic piece are respectively connected to the second end face of the first piston and the first end face of the second piston; one end of the second elastic piece is connected to the first end face of the second piston; the second elastic piece is coaxially sleeved in the first spring, and the free length of the second elastic piece is smaller than that of the first spring; and two ends of the third elastic piece respectively abut against the end surface of the nut of the ball screw pair and the second end surface of the second piston.
Furthermore, a nut limiting device is arranged on the inner wall of the cylinder body; the nut limiting device can prevent the nut from continuously approaching the second piston when moving to the second limit position.
Furthermore, a piston limiting device is arranged on the inner wall of the cylinder body; the piston limiting device can prevent the first piston from moving to a first limit position and then continuously approaching the brake pedal.
Furthermore, a bearing mounting hole is formed in the bottom of the cylinder body, and a tapered roller bearing is arranged between the hole wall of the bearing mounting hole and a lead screw of the ball screw pair.
Further, the detection unit comprises an angle sensor and a force sensor, and the angle sensor and the force sensor are both arranged at the lower part of the brake pedal.
Further, the control unit comprises an ECU electronic control unit.
Further, the desired pedal reaction force value includes a medium-high strength pedal reaction force value or a low strength pedal reaction force value; the calculating of the desired pedal reaction force value specifically includes: calculating the angular displacement change rate according to the pedal angular displacement value; judging whether the angular displacement change rate is greater than a first preset value or not; if yes, calculating an expected middle-high strength pedal reaction force value; if not, the desired low-intensity pedal reaction force value is calculated.
Further, controlling the power transmission mechanism to start according to the magnitude relation between the pedal reaction force value detected by the detection unit and the expected pedal reaction force value so as to adjust the feeding amount of the nut in the ball screw pair, specifically comprising: judging whether the pedal reaction force value detected by the detection unit is smaller than the expected pedal reaction force value or not, if so, controlling a driving motor to rotate positively to increase the feeding amount of a nut in the ball screw pair; and if not, controlling the driving motor to reversely rotate so as to reduce the feeding amount of the nut in the ball screw pair.
Compared with the prior art, the application has the following beneficial effects:
1. the pretightening force that this application embodiment drove the vice regulation third elastic component of ball through driving motor, can adjust footboard reaction value wantonly in certain extent, has overcome traditional footboard sensation simulator, in case the structure is confirmed then the drawback that the relation between footboard power and the footboard displacement is confirmed thereupon, and when automatically controlled unit became invalid, still has footboard sensation simulation function with the help of mechanical structure.
2. The integration level of the embodiment of the application is higher, and the structure that hydraulic system realizes becoming the footboard sensation through the solenoid valve has been abandoned, has reduced whole volume.
3. The embodiment of the application adjusts the feeding amount through the ball screw, and has the advantages of high precision and small vibration.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic structural diagram of a variable-feel brake-by-wire pedal feel simulator according to an embodiment of the present application;
FIG. 2 is a flow chart of the operation of a variable feel brake-by-wire pedal feel simulator in accordance with an embodiment of the present application;
FIG. 3 is a graph of pedal reaction force values versus pedal angular displacement values in a variable-feel brake-by-wire pedal feel simulator according to an embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
In the description of the present application, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, merely for convenience of description and simplicity of description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, are not to be construed as limiting the present application.
In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; the specific meaning of the above terms in this application can be understood as appropriate by one of ordinary skill in the art.
The terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless otherwise specified.
Referring to fig. 1, an embodiment of the present application provides a variable-feel brake-by-wire pedal feel simulator including a pedal assembly, a brake pedal feel simulation mechanism, a power transmission mechanism, a detection unit, and a control unit.
The pedal assembly comprises a brake pedal 1 and a push rod 2, wherein the first end of the push rod 2 is hinged on the brake pedal 1.
The brake pedal feel simulation mechanism comprises a cylinder body 3, a first piston 4, a second piston 5, a ball screw pair 6 and a power transmission mechanism.
The first piston 4, the second piston 5 and the ball screw pair 6 are sequentially arranged in the cylinder 3 along the axial direction, and the first piston 4 and the second piston 5 can reciprocate along the axial direction of the cylinder 3.
The second end of the push rod 2 is connected to a first end face of a first piston 4. A first elastic member 8 is arranged between the first piston 4 and the second piston 5, and the first elastic member 8 is capable of providing a force to the second piston 5 in a direction away from the first piston 4. Specifically, the first elastic member 8 is a compression spring, and two ends of the first elastic member 8 are respectively connected to the second end surface of the first piston 4 and the first end surface of the second piston 5.
The first end surface of the second piston 5 is further fixedly connected with a second elastic piece 9, the second elastic piece 9 can provide force for the second piston 5 in the direction away from the first piston 4, and a gap is formed between the second elastic piece 9 and the first piston 4 when the second elastic piece 9 is in a free state. Specifically, the second elastic member 9 is also a compression spring, one end of the second elastic member 9 is connected to the first end surface of the second piston 5, the second elastic member 9 is coaxially sleeved in the first spring, and the free length of the second elastic member is smaller than that of the first spring.
A third elastic member 10 is provided between the ball screw pair 6 and the second piston 5, and the third elastic member 10 can provide a force to the second piston 5 in a direction away from the ball screw pair 6. Specifically, the third elastic member 10 is also a compression spring, and two ends of the third elastic member respectively abut against the end surface of the nut of the ball screw pair 6 and the second end surface of the second piston 5.
The inner wall of the cylinder body 3 is also provided with a piston limiting device 11 and a nut limiting device 12. The piston limiting device 11 can prevent the first piston 4 from moving to the first limit position and continuing to approach the brake pedal 1, and the nut limiting device 12 can prevent the nut from moving to the second limit position and continuing to approach the second piston 5. Specifically, the piston limiting device 11 and the nut limiting device 12 can be limiting rings fixedly connected to the inner wall of the cylinder body.
The lead screw 61 of the ball screw pair 6 is rotatably connected to the bottom of the cylinder 3, and the lead screw 61 of the ball screw pair 6 extends out of the cylinder 3 and then is connected with the power transmission mechanism. Specifically, the bottom of the cylinder 3 is provided with a bearing mounting hole 31, and a tapered roller bearing 13 is provided between the hole wall of the bearing mounting hole 31 and the lead screw 62 of the ball screw assembly 6.
The power transmission mechanism comprises a driving motor 14 and a cylindrical gear pair 15, the output end of the driving motor 14 is connected with the input end of the cylindrical gear pair 15, and the output end of the cylindrical gear pair 15 is connected with the screw rod end of the ball screw pair 6.
The detection unit is capable of detecting a pedal angular displacement value and a pedal reaction force value. Specifically, the detection unit includes an angle sensor 16 and a force sensor 17, and both the angle sensor 16 and the force sensor 17 are disposed at a lower portion of the brake pedal 1. The angle sensor 16 is used to detect the pedal angular displacement value. The force sensor 17 is used to detect a pedal reaction force value.
The control unit includes an ECU electronic control unit 18. The ECU electronic control unit 18 is electrically connected to both the detection unit and the drive motor 14. The ECU electronic control unit 18 is configured to:
s1, receiving the pedal angular displacement value detected by the detection unit
Figure BDA0003656378110000061
And a pedal reaction force value F;
s2, calculating the expected pedal reaction force value F 1 (ii) a Wherein the desired pedal reaction force value F 1 The method comprises the following steps of (1) obtaining a medium-high strength pedal reaction force value or a low strength pedal reaction force value:
s21, according to the angular displacement value of the pedal
Figure BDA0003656378110000062
Calculating the angular displacement change rate;
s22, judging whether the angular displacement change rate is larger than a first preset value or not; if yes, calculating an expected middle-high strength pedal reaction force value; if not, the desired low-intensity pedal reaction force value is calculated. It should be noted that the first preset value is a pedal speed threshold.
S3, judging the pedal reaction force value F detected by the detection unit and the expected pedal reaction force value F 1 Whether the absolute value of the difference of (b) is greater than the secondPresetting a value; wherein the second preset value is the detected pedal reaction force value F and the expected pedal reaction force value F 1 The maximum error value therebetween; if yes, the pedal reaction force value F detected by the detection unit and the expected pedal reaction force value F are obtained 1 The magnitude relation between the pedal reaction force value F and the expected pedal reaction force value F controls the power transmission mechanism to start so as to adjust the feed amount of the nut 62 in the ball screw pair until the pedal reaction force value F detected by the detection unit and the expected pedal reaction force value F 1 Is less than or equal to a second preset value:
s31, judging the pedal reaction force value F detected by the detection unit and the expected pedal reaction force value F 1 Whether the absolute value of the difference value of (a) is greater than a second preset value; if yes, go to S32; if not, the user can not select the specific application,
proceed to S33;
s32, judging whether the pedal reaction force value F detected by the detection unit is smaller than the expected pedal reaction force value F 1 If yes, controlling the driving motor 14 to rotate positively to increase the feeding amount of the nut 62 in the ball screw pair and increase the pedal reaction force value F detected by the detection unit; if not, the driving motor 14 is controlled to rotate reversely to reduce the feed amount of the nut 62 in the ball screw pair, and the pedal reaction force value F detected by the detection unit is reduced.
S33, judging the pedal reaction force value F detected by the detection unit and the expected pedal reaction force value F 1 Whether the absolute value of the difference value of (a) is less than a second preset value; if yes, go to S4; if not, the process proceeds to S32.
S4, judging pedal angular displacement
Figure BDA0003656378110000071
If the value is zero, controlling the driving motor 14 to adjust the nut 62 in the ball screw pair to return to the initial position, and ending the braking; if not, the process proceeds to S1.
The brake pedal 1 in the embodiment of the application is provided with a force sensor 17 and an angle sensor 16 below, and the pedal reaction force value is provided by three springs. The feed amount of the nut 62 is adjusted by the ball screw adjusting device driven by the driving motor so as to adjust the elastic force on the third elastic element, thereby achieving the purpose of adjusting the integral pedal reaction force value, and the axial force borne by the screw 62 is transmitted to the cylinder wall through the tapered roller bearing 13.
Specifically, the brake pedal 1 pushes the first piston 4, the first elastic member 8, the second piston 5 and the first elastic member 10 to move in sequence after being stepped on. At this time, the ECU 18 drives the motor 14 to rotate, and the lead screw 61 of the ball screw assembly is rotated by the spur gear pair 15 to move the nut 62 and the third elastic member 10 connected to the nut 62 to the right, thereby adjusting the compression reaction force of the third elastic member 10. The drive motor 14 adjusts the feed r of the nut 62 so that the pedal reaction force value F felt by the driver is equal to the desired pedal reaction force value F calculated by the ECU control unit 18 1 。
Referring to fig. 2 and 3, the operation principle of the variable-feel brake-by-wire pedal feel simulator according to the embodiment of the present application is as follows:
when a driver starts braking, the driver steps on the brake pedal 1, the angle sensor 16 transmits the collected angular displacement value to the ECU (electronic control Unit) 18, the ECU 18 divides braking into two conditions of low-intensity braking and medium-high intensity braking according to whether the angular displacement change rate is larger than a first preset value, and an expected pedal reaction force value F is calculated according to different conditions 1 。
When the pedal reaction force value F received by the driver and collected by the force sensor 17 is equal to the expected pedal reaction force value F 1 When the absolute value of the difference between the values is greater than the second preset value, the ECU 18 activates the driving motor 14 to adjust the feed amount of the nut 62 in the ball screw pair, thereby adjusting the pedal reaction force value F received by the driver to be equal to the desired pedal reaction force value F1 or the difference to be within the allowable range. The working flow is shown in figure 2.
During low-intensity braking (i.e. when the second elastic element 9 is not in contact with the first piston 4):
the ECU (electronic control Unit) 18 receives the pedal reaction force F and the pedal angular displacement value acquired by the force sensor 17 and the angle sensor 16
Figure BDA0003656378110000084
The ECU electronic control unit 18 calculates a desired pedal reaction force value F 1 ；
The ECU 18 determines the pedal reaction force value F detected by the force sensor 17 and the desired pedal reaction force value F 1 If the absolute value of the difference is greater than the second preset value, whether the pedal reaction force value F is smaller than the expected pedal reaction force value F is judged 1 If yes, controlling the driving motor 14 to rotate positively to increase the feeding amount of the nut 62 in the ball screw pair and increase the pedal reaction force value F detected by the detection unit; if not, the driving motor 14 is controlled to rotate reversely to reduce the feeding amount of the nut 62 in the ball screw pair, and the pedal reaction force value F detected by the detection unit is reduced.
The ECU 18 determines the pedal reaction force value F detected by the detection unit and the desired pedal reaction force value F 1 Whether the absolute value of the difference value of (a) is less than a second preset value; if yes, judging the angular displacement of the pedal
Figure BDA0003656378110000085
If the value is zero, controlling the driving motor 14 to adjust the nut 62 in the ball screw pair to return to the initial position, and ending the braking; if not, the next cycle is started.
At this time, the pedal reaction force value F (i.e. the real brake reaction force) and the pedal angular displacement value
Figure BDA0003656378110000086
The relationship of (1) is:
Figure BDA0003656378110000081
wherein, K 1 、K 2 And K 3 The compression coefficients of the first elastic member 8, the second elastic member 9 and the third elastic member 10, respectively;
r is the feed amount of the nut 62;
Figure BDA0003656378110000082
the pedal angular displacement value;
a is the distance from the connecting point of the brake pedal 1 and the first piston 4 to the rotation center of the brake pedal 1; then
Figure BDA0003656378110000083
I.e. the displacement of the first piston 4; b is the lever ratio of the brake pedal 1.
When the driver releases the brake pedal 1, the ECU electronic control unit 18 receives signals from the angle sensor 16 and the force sensor 17, controls the driving motor 14 to drive the screw 61 to rotate so as to make the nut 62 return to the initial position, and the first piston 4 and the second piston 5 return to the initial position under the action of the reaction force of the corresponding elastic members.
During medium and high intensity braking (i.e. after the second elastic element 9 contacts the first piston 4):
the first half of the brake works in the same way as the low-intensity brake, when the first piston 4 moves into contact with the second elastic element 9, the second elastic element 9 starts to be compressed, and the simulator brake counterforce is provided by connecting the second elastic element 9 in parallel with the first elastic element 8 and then connecting the second elastic element in series with the third elastic element 10. At this time, the ECU control unit 18 controls the rotation of the driving motor 14, the lead screw 61 is rotated by the cylindrical gear pair 15 to move the nut 62 and the third elastic member 10 to the right, so as to adjust the compression reaction force of the third elastic member 10, and the driving motor 14 adjusts the feeding amount r of the nut 62 to make the pedal force F of the driver equal to the desired pedal reaction force value F calculated by the ECU 1 。
At this time, the pedal reaction force value F (i.e. the real brake reaction force) and the pedal angular displacement value
Figure BDA0003656378110000092
The relationship of (1) is:
Figure BDA0003656378110000091
when the driver releases the brake pedal 1, the ECU electronic control unit 18 receives signals from the angle sensor 16 and the force sensor 17, controls the driving motor 14 to drive the screw 61 to rotate so as to make the nut 62 return to the initial position, and the first piston 4 and the second piston 5 return to the initial position under the action of the reaction force of the corresponding elastic members.
When the active system fails:
when the ECU 18 fails, the pedal simulator becomes a passive two-stage pedal simulator, i.e. when the two conditions r are equal to 0, the driver is still provided with a pedal reaction force value.
Referring to fig. 3, where α is the maximum angular pedal displacement;
the broken lines A and B in the figure are the relationship curves when the feeding amount of the nut 62 is 0 and the maximum position (the position of the nut limiting device) respectively, and the pedal reaction force value F expected in the work flow is adjusted 1 And the calculation relation with the pedal angular travel, theoretically, a relation curve of the pedal travel and the pedal reaction force value can be adjusted at will in a shaded part in the graph, wherein C and D are two different demonstration curves of the middle-high intensity braking condition, and E is one demonstration curve of the low intensity braking condition.
The above is only an embodiment of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions within the technical scope of the present disclosure should be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (10)

1. A brake-by-wire pedal feel simulator with variable feel is characterized in that,
the brake pedal feeling simulation device comprises a pedal assembly, a brake pedal feeling simulation mechanism, a power transmission mechanism, a detection unit and a control unit;
the pedal assembly comprises a brake pedal and a push rod, and the first end of the push rod is hinged to the brake pedal;
the brake pedal feeling simulation mechanism comprises a cylinder body, a first piston, a second piston, a ball screw pair and a power transmission mechanism;
the first piston, the second piston and the ball screw pair are sequentially arranged in the cylinder body, and the first piston and the second piston can reciprocate along the axial direction of the cylinder body; the second end of the push rod is connected with the first end face of the first piston; a first elastic piece is arranged between the first piston and the second piston and can provide force for the second piston in a direction away from the first piston; the first end of the second piston is fixedly connected with a second elastic piece, the second elastic piece can provide a force in the direction away from the first piston for the second piston, and a gap is formed between the second elastic piece and the first piston when the second elastic piece is in a free state;
the screw rod of the ball screw pair is rotatably connected to the bottom of the cylinder body, and the screw rod of the ball screw pair extends out of the cylinder body and then is connected with the power transmission mechanism; a third elastic piece is arranged between the ball screw pair and the second piston, and the third elastic piece can provide force for the second piston in the direction away from the ball screw pair;
the detection unit is capable of detecting the pedal angular displacement value and the pedal reaction force value;
the control unit is electrically connected with the detection unit and the power transmission mechanism;
the control unit is configured to:
receiving the pedal angular displacement value and the pedal reaction force value detected by the detection unit;
calculating a desired pedal reaction force value;
and judging whether the absolute value of the difference value between the pedal reaction force value detected by the detection unit and the expected pedal reaction force value is larger than a second preset value or not, if so, controlling the power transmission mechanism to start according to the magnitude relation between the pedal reaction force value detected by the detection unit and the expected pedal reaction force value so as to adjust the feeding amount of the nut in the ball screw pair until the difference value between the pedal reaction force value detected by the detection unit and the expected pedal reaction force value is smaller than or equal to the second preset value.
2. The variable feel brake-by-wire pedal feel simulator of claim 1, wherein the power transmission mechanism comprises a drive motor and a spur gear pair, an output of the drive motor being connected to an input of the spur gear pair, an output of the spur gear pair being connected to a lead screw end of the ball screw pair.
3. The variable-feel brake-by-wire pedal feel simulator of claim 1, wherein the first, second and third resilient members are compression springs; two ends of the first elastic piece are respectively connected to the second end face of the first piston and the first end face of the second piston; one end of the second elastic piece is connected to the first end face of the second piston; the second elastic piece is coaxially sleeved in the first spring, and the free length of the second elastic piece is smaller than that of the first spring; and two ends of the third elastic piece respectively abut against the end surface of the nut of the ball screw pair and the second end surface of the second piston.
4. The brake-by-wire pedal feel simulator with variable feel according to claim 1, wherein a nut limiting device is arranged on the inner wall of the cylinder body; the nut limiting device can prevent the nut from continuously approaching the second piston when moving to the second limit position.
5. The brake-by-wire pedal feel simulator of variable feel of claim 1, wherein a piston stop is provided on the inner wall of the cylinder; the piston limiting device can prevent the first piston from moving to a first limit position and then continuously approaching the brake pedal.
6. The variable-feel brake-by-wire pedal feel simulator of claim 1, wherein a bearing mounting hole is provided at the bottom of the cylinder body, and a tapered roller bearing is provided between a hole wall of the bearing mounting hole and a lead screw of the ball screw pair.
7. The variable-feel brake-by-wire pedal feel simulator of claim 1, wherein the detection unit includes an angle sensor and a force sensor, both disposed at a lower portion of the brake pedal.
8. The variable feel brake-by-wire pedal feel simulator of claim 1, wherein the control unit comprises an ECU electronic control unit.
9. The variable-feel brake-by-wire pedal feel simulator of claim 1, wherein the desired pedal reaction force value comprises a medium-high-strength pedal reaction force value or a low-strength pedal reaction force value; the calculating of the desired pedal reaction force value specifically includes:
calculating the angular displacement change rate according to the pedal angular displacement value;
judging whether the angular displacement change rate is greater than a first preset value or not; if yes, calculating an expected middle-high strength pedal reaction force value; if not, the desired low-intensity pedal reaction force value is calculated.
10. The brake-by-wire pedal feel simulator with variable feel according to claim 1, wherein the power transmission mechanism is controlled to be actuated to adjust the feed amount of the nut in the ball screw pair according to the magnitude relationship between the pedal reaction force value detected by the detection unit and the desired pedal reaction force value, and specifically comprises:
judging whether the pedal reaction force value detected by the detection unit is smaller than the expected pedal reaction force value or not, if so, controlling a driving motor to rotate positively to increase the feeding amount of a nut in the ball screw pair; and if not, controlling the driving motor to reversely rotate so as to reduce the feeding amount of the nut in the ball screw pair.
CN202210560440.7A 2022-05-23 2022-05-23 Variable-feel linear control brake pedal feel simulator Active CN114954380B (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN203126814U (en) * 2013-03-19 2013-08-14 吉林大学 Active journey simulator for brake pedal
CN104787020A (en) * 2015-03-20 2015-07-22 同济大学 Electronic hydraulic braking system with novel decoupling mode
CN109624957A (en) * 2019-02-26 2019-04-16 吉林大学 A kind of integrated electric energy assisted braking system with novel coupled modes
CN111301379A (en) * 2020-03-05 2020-06-19 吉林大学 Semi-active brake-by-wire system pedal feel simulator
CN112319444A (en) * 2020-12-01 2021-02-05 吉林大学 Pedal feel simulator applied to brake-by-wire system and control method thereof

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN203126814U (en) * 2013-03-19 2013-08-14 吉林大学 Active journey simulator for brake pedal
CN104787020A (en) * 2015-03-20 2015-07-22 同济大学 Electronic hydraulic braking system with novel decoupling mode
CN109624957A (en) * 2019-02-26 2019-04-16 吉林大学 A kind of integrated electric energy assisted braking system with novel coupled modes
CN111301379A (en) * 2020-03-05 2020-06-19 吉林大学 Semi-active brake-by-wire system pedal feel simulator
CN112319444A (en) * 2020-12-01 2021-02-05 吉林大学 Pedal feel simulator applied to brake-by-wire system and control method thereof

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