Transmission ratio matching test method of passenger vehicle steer-by-wire system

Abstract

The invention discloses a transmission ratio matching test method for a passenger vehicle steer-by-wire system, and belongs to the technical field of automobiles, the test method comprises the following steps: converting a steering transmission ratio of a vehicle into a dynamic characteristic parameter of the vehicle, and carrying out vehicle objective data acquisition under different working conditions through an initially set transmission ratio change characteristic; therefore, a steering characteristic model of the vehicle is established, an evaluator directly adjusts a demand index of vehicle yaw response based on the model, and a control system outputs a steering angle request through the request index. After the method is used for carrying out transmission ratio matching, evaluation personnel can directly set steering characteristic indexes instead of indirectly adjusting the steering characteristic indexes through the transmission ratio, the different setting effects are more visual, developers can conveniently know the actual effects and display the actual effects on a user side, and the workload and the working difficulty of development verification are reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of automobiles, and in particular relates to a transmission ratio matching test method for a steer-by-wire system of a passenger vehicle. Background Art

[0002] The transmission ratio matching test of the steer-by-wire system is a test process for setting the transmission ratio of the steer-by-wire system for a passenger car equipped with a steer-by-wire system. The test process needs to set the transmission ratio value based on the subjective evaluation of the test personnel. Since the steer-by-wire system does not have the mechanical transmission mechanism in the traditional steering system, the transmission ratio can be set arbitrarily according to the demand. The existing technical solution is to obtain the corresponding steering transmission ratio according to the corresponding relationship between the steering wheel angle and the steering gear transmission system.

[0003] The existing angle control logic sets the steering transmission ratio directly according to the angle relationship, which is close to the transmission ratio relationship between the steering wheel angle and the wheel angle of the traditional steering gear. For matching evaluators, the transmission ratio cannot fully and clearly characterize the steering characteristics of the vehicle, and it is necessary to verify various steering conditions after changing the transmission ratio. The evaluation workload is large, and it is difficult to fully cover the evaluation conditions. The manpower and material costs of the test are high, and it is not convenient to customize the settings to adjust the vehicle steering characteristics. Summary of the invention

[0004] In view of the above-mentioned defects existing in the prior art, the present invention provides a transmission ratio matching test method for a passenger car steer-by-wire system, which converts the steering transmission ratio of the vehicle into the dynamic characteristic parameters of the vehicle, collects objective data of the vehicle under different working conditions through a certain transmission ratio change characteristic that is initially set, and thus establishes a steering characteristic model of the vehicle. The evaluator directly adjusts the demand index of the vehicle's yaw response based on the model, and the control system outputs the angle request through the request index. After using the method of the present invention to match the transmission ratio, the evaluator can directly set the steering characteristic index instead of indirectly adjusting it through the transmission ratio. The effects of different settings are more intuitive, which is convenient for developers to understand the actual effects and user-side display, and reduces the workload and difficulty of development verification.

[0005] The present invention is achieved through the following technical solutions:

[0006] A transmission ratio matching test method for a passenger car steer-by-wire system comprises the following steps:

[0007] Step 1: Test vehicle preparation;

[0008] Step 2: Vehicle steering characteristics measurement;

[0009] The vehicle's inertial navigation sensor is used to collect the vehicle's real-time lateral acceleration and yaw rate, and the vehicle's steering wheel angle sensor is used to record the steering wheel angle. The steering characteristics of the test vehicle at different speeds and different steering wheel angles are tested.

[0010] Step 3: Test data processing;

[0011] The steering characteristic data obtained from the test is processed to obtain the relationship between the yaw angular velocity W and the steering wheel angle a1 and the vehicle speed V, that is, W = f1 (a1, V);

[0012] Step 4: The calibration test personnel conduct a subjective evaluation of the vehicle status;

[0013] Step 5: Transmission ratio calibration;

[0014] According to the evaluation result in step 4, the target yaw rate W1 is determined. The actuator of the steer-by-wire system determines the new pinion angle a1 required to achieve W1 under the same steering wheel angle a1 according to the relationship between the yaw rate W, the steering wheel angle a1, and the vehicle speed V obtained in step 3: W = f1(a1, V), and the relationship between the steering wheel angle a1 and the steering gear pinion angle a: a1 = f2(a, V). This completes the new transmission ratio matching. Then, steps 4 and 5 are continuously iterated until the yaw rate W executed by the vehicle under various working conditions meets the expectations of the calibrator, that is, the steering transmission ratio matching process is completed by optimizing the characteristics of the vehicle's yaw rate.

[0015] Furthermore, step one specifically includes the following contents:

[0016] The vehicle shall be prepared in accordance with the requirements of vehicle maneuverability and stability tests. The vehicle's steer-by-wire system shall have basic steering transmission ratio logic. During steering operation, the speed ratio between the steering wheel rotation and the small gear rotation of the driving rack inside the steering gear shall remain unchanged. The steering wheel angle a1 and the small gear angle a of the rack and pinion steering gear have the following corresponding relationship: a1=f2(a,V).

[0017] Furthermore, in step 2, the vehicle steering characteristic measurement includes a low-speed steering characteristic measurement and a high-speed steering characteristic measurement.

[0018] Furthermore, the low-speed steering characteristic measurement specifically includes the following steps:

[0019] A1. The test vehicle speed is set to 5km / h, 10km / h, 20km / h, and 30km / h;

[0020] A2. Keep the vehicle speed at 5 km / h, turn the steering wheel to 5°, 10°, 20°, 30°, 45°, 60°, 90°, 120°, 150°, 180°, 240°, 360° and then keep it fixed. After the vehicle is stable, maintain this state for 3 seconds.

[0021] A3. When the front wheel grip reaches its limit as the steering wheel angle increases and the vehicle's yaw rate cannot continue to increase, it means that the vehicle's own performance cannot reach a higher yaw rate and the vehicle is in an understeering state. The current steering wheel angle and the corresponding steering actuator position are recorded as the execution upper limit and the measurement is stopped.

[0022] A4. Increase the test vehicle speed to the next test vehicle speed and repeat steps A2 and A3;

[0023] A5. Calculate the average yaw rate of the vehicle within 3 seconds in step A2, obtain the relationship between the yaw rate and lateral acceleration corresponding to different steering wheel angles of the vehicle, and fit the relationship between the yaw rate W1 and the steering wheel angle a1 at each vehicle speed as follows: W v＝5km / h =f1(a1),W v＝10km / h =f1(a1),W v＝20km / h =f1(a1),W v＝30km / h =f1(a1).

[0024] Furthermore, the high-speed steering characteristic measurement specifically includes the following steps:

[0025] B1. The test speed is set to 40km / h, 50km / h, 60km / h, 80km / h, 100km / h, 120km / h, and 150km / h;

[0026] B2. Maintain the vehicle speed at the test speed + 5;

[0027] B3. Without applying driving force or braking force, increase the steering wheel angle input from the middle position of the steering wheel to one side at a speed of 20° / s until the vehicle exhibits one of the following two phenomena, indicating that the vehicle cannot stably maintain a higher yaw rate. Record the steering wheel angle and the corresponding steering actuator position when the corresponding phenomenon occurs as the execution upper limit of the current working condition, and perform two measurements on each side;

[0028] Situation 1: The front axle reaches the grip limit, and the yaw acceleration of the vehicle cannot continue to increase as the steering wheel angle increases, resulting in obvious understeer;

[0029] Situation 2: The rear axle reaches the grip limit, and as the steering wheel angle increases, the vehicle's turning radius is significantly narrowed or it slips sideways, and it cannot maintain stable driving, and obvious oversteering occurs;

[0030] B4. Repeat step B3 to increase the steering wheel angle input on the other side and perform two measurements;

[0031] B5. Increase the vehicle speed to the next test speed and repeat steps A2, A3 and A4;

[0032] B6. Take the average of the curves of the change relationship between the yaw rate, lateral acceleration and steering wheel angle recorded twice on the left and right sides, and obtain the relationship between the yaw rate W and the steering wheel angle a1 at each vehicle speed: W v＝40km / h =f1(a1),W v＝50km / h =f1(a1),W v＝60km / h =f1(a1)…….

[0033] Furthermore, in step 3, the steering characteristic data obtained from the test is processed, including the following contents:

[0034] The relationship curves (W) between the yaw angular velocity W obtained in step 2 and the steering wheel angle a1 are v＝5km / h =f1(a1),W v＝10km / h =f1(a1),W v＝20km / h =f1(a1),W v＝30km / h =f1(a1),W v＝40km / h =f1(a1),W v＝50km / h =f1(a1),W v＝60km / h =f1(a1)……) According to the interpolation method, the relationship between W and a1, V is obtained: W=f1(a1,V); according to a1=f2(a,V), W=f3(a,V) is obtained, that is, the relationship between the yaw angular velocity W and the steering actuator pinion angle a and the vehicle speed V.

[0035] Furthermore, step 4 includes the following:

[0036] The calibration personnel drive the vehicle from low speed to high speed, perform parking operations, low-speed maneuvers, turning lane changes, and high-speed lane changes; determine the following:

[0037] 1) The corresponding working conditions that require changing the steering gear ratio, i.e. the corresponding vehicle speed and steering wheel angle;

[0038] 2) The difference between the yaw rate of the corresponding working condition and the driver's expectation;

[0039] 3) Determine the difference between the yaw angular velocity under the corresponding working condition and the yaw angular velocity of the control target.

[0040] In a second aspect, the present invention further provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, a transmission ratio matching test method for a passenger car steer-by-wire system as described in any one of the embodiments of the present invention is implemented.

[0041] In a third aspect, the present invention further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements a transmission ratio matching test method for a passenger vehicle steer-by-wire system as described in any one of the embodiments of the present invention.

[0042] Compared with the prior art, the advantages of the present invention are as follows:

[0043] The present invention discloses a transmission ratio matching test method for a passenger car steer-by-wire system. The test method converts the steering transmission ratio of the vehicle into a dynamic characteristic parameter of the vehicle, collects objective data of the vehicle under different working conditions through a certain transmission ratio change characteristic that is initially set, and thus establishes a steering characteristic model of the vehicle. The evaluator directly adjusts the demand index of the vehicle's yaw response based on the model, and the control system outputs a turning angle request through a request index. After using the method of the present invention to match the transmission ratio, the evaluator can directly set the steering characteristic index instead of indirectly adjusting it through the transmission ratio. The effects of different settings are more intuitive, which is convenient for developers to understand the actual effects and user-side display, and reduces the workload and difficulty of development verification. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0045] Figure 1 A schematic flow chart of a transmission ratio matching test method for a passenger vehicle steer-by-wire system according to the present invention;

[0046] Figure 2 A schematic diagram for matching and calibrating a certain working condition during the test;

[0047] Figure 3 This is a schematic diagram of the structure of an electronic device in Embodiment 2 of the present invention. DETAILED DESCRIPTION

[0048] In order to clearly and completely describe the technical solution and its specific working process of the present invention, the specific implementation methods of the present invention are as follows in conjunction with the accompanying drawings of the specification:

[0049] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0050] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0051] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0052] Example 1

[0053] like Figure 1 As shown in FIG. 1 , a transmission ratio matching test method of a passenger car steer-by-wire system of this embodiment is shown, which specifically includes the following steps:

[0054] Step 1: Test vehicle preparation;

[0055] The vehicle shall be prepared in accordance with the requirements of vehicle maneuverability and stability tests. The vehicle's steer-by-wire system shall have basic steering transmission ratio logic. During steering operation, the speed ratio between the steering wheel rotation and the small gear rotation of the driving rack inside the steering gear shall remain unchanged. The steering wheel angle a1 and the small gear angle a of the rack and pinion steering gear have the following corresponding relationship: a1=f2(a,V).

[0056] Step 2: Vehicle steering characteristics measurement;

[0057] The vehicle's inertial navigation sensor is used to collect the vehicle's real-time lateral acceleration and yaw rate, and the vehicle's steering wheel angle sensor is used to record the steering wheel angle. The steering characteristics of the test vehicle at different speeds and different steering wheel angles are tested.

[0058] The vehicle steering characteristic measurement includes a low-speed steering characteristic measurement and a high-speed steering characteristic measurement.

[0059] The low-speed steering characteristic measurement specifically includes the following steps:

[0060] A1. The test vehicle speed is set to 5km / h, 10km / h, 20km / h, and 30km / h;

[0061] A2. Keep the vehicle speed at 5 km / h, turn the steering wheel to 5°, 10°, 20°, 30°, 45°, 60°, 90°, 120°, 150°, 180°, 240°, 360° and then keep it fixed. After the vehicle is stable, maintain this state for 3 seconds.

[0062] A3. When the front wheel grip reaches its limit as the steering wheel angle increases and the vehicle's yaw rate cannot continue to increase, it means that the vehicle's own performance cannot reach a higher yaw rate and the vehicle is in an understeering state. The current steering wheel angle and the corresponding steering actuator position are recorded as the execution upper limit and the measurement is stopped.

[0063] A4. Increase the test vehicle speed to the next test vehicle speed and repeat steps A2 and A3;

[0064] A5. Calculate the average yaw rate of the vehicle within 3 seconds in step A2, obtain the relationship between the yaw rate and lateral acceleration corresponding to different steering wheel angles of the vehicle, and fit the relationship between the yaw rate W1 and the steering wheel angle a1 at each vehicle speed as follows: W v＝5km / h =f1(a1),W v＝10km / h =f1(a1),W v＝20km / h =f1(a1),W v＝30km / h =f1(a1).

[0065] The high-speed steering characteristic measurement specifically includes the following steps:

[0066] B1. The test speed is set to 40km / h, 50km / h, 60km / h, 80km / h, 100km / h, 120km / h, and 150km / h;

[0067] B2. Maintain the vehicle speed at the test speed + 5;

[0068] B3. Without applying driving force or braking force, increase the steering wheel angle input from the middle position of the steering wheel to one side at a speed of 20° / s until the vehicle exhibits one of the following two phenomena, indicating that the vehicle cannot stably maintain a higher yaw rate. Record the steering wheel angle and the corresponding steering actuator position when the corresponding phenomenon occurs as the execution upper limit of the current working condition, and perform two measurements on each side;

[0069] Situation 1: The front axle reaches the grip limit, and the yaw acceleration of the vehicle cannot continue to increase as the steering wheel angle increases, resulting in obvious understeer;

[0070] Situation 2: The rear axle reaches the grip limit, and as the steering wheel angle increases, the vehicle's turning radius is significantly narrowed or it slips sideways, and it cannot maintain stable driving, and obvious oversteering occurs;

[0071] B4. Repeat step B3 to increase the steering wheel angle input on the other side and perform two measurements;

[0072] B5. Increase the vehicle speed to the next test speed and repeat steps A2, A3 and A4;

[0073] B6. Take the average of the curves of the change relationship between the yaw rate, lateral acceleration and steering wheel angle recorded twice on the left and right sides, and obtain the relationship between the yaw rate W and the steering wheel angle a1 at each vehicle speed: W v＝40km / h =f1(a1),W v＝50km / h =f1(a1),W v＝60km / h =f1(a1)…….

[0074] Step 3: Test data processing;

[0075] The steering characteristic data obtained from the test is processed to obtain the relationship between the yaw angular velocity W and the steering wheel angle a1 and the vehicle speed V, that is, W = f1 (a1, V);

[0076] In step 3, the steering characteristic data obtained from the test is processed, including the following contents:

[0077] The relationship curves (W) between the yaw angular velocity W obtained in step 2 and the steering wheel angle a1 are v＝5km / h =f1(a1),W v＝10km / h =f1(a1),W v＝20km / h =f1(a1),W v＝30km / h =f1(a1),W v＝40km / h =f1(a1),W v＝50km / h =f1(a1),W v＝60km / h=f1(a1)……) According to the interpolation method, the relationship between W and a1, V is obtained: W=f1(a1,V); According to a1=f2(a,V), W=f3(a,V) is obtained, that is, the relationship between the yaw angular velocity W and the steering actuator pinion angle a and the vehicle speed V;

[0078] Step 4: The calibration test personnel conduct a subjective evaluation of the vehicle status;

[0079] Furthermore, step 4 includes the following:

[0080] The calibration personnel drive the vehicle from low speed to high speed, perform parking operations, low-speed maneuvers, turning lane changes, and high-speed lane changes; determine the following:

[0081] 1) The corresponding working conditions that require changing the steering gear ratio, i.e. the corresponding vehicle speed and steering wheel angle;

[0082] 2) The difference between the yaw rate of the corresponding working condition and the driver's expectation;

[0083] 3) Determine the difference between the yaw angular velocity under the corresponding working condition and the yaw angular velocity of the control target.

[0084] Step 5: Transmission ratio calibration;

[0085] According to the evaluation result in step 4, the target yaw rate W1 is determined. The actuator of the steer-by-wire system determines the new pinion angle a1 required to achieve W1 under the same steering wheel angle a1 according to the relationship between the yaw rate W, the steering wheel angle a1, and the vehicle speed V obtained in step 3: W = f1(a1, V), and the relationship between the steering wheel angle a1 and the steering gear pinion angle a: a1 = f2(a, V). This completes the new transmission ratio matching. Then, steps 4 and 5 are continuously iterated until the yaw rate W executed by the vehicle under various working conditions meets the expectations of the calibrator, that is, the steering transmission ratio matching process is completed by optimizing the characteristics of the vehicle's yaw rate.

[0086] In this embodiment, the test preparation is performed according to step 1. After obtaining the test vehicle, the test vehicle is subjected to necessary pre-test preparation. In this embodiment, the initial scheme before the test is that the relationship between the steering wheel angle and the pinion angle in the steering actuator is 1:1 at any vehicle speed, that is, the driver's input steering wheel angle is completely consistent with the pinion angle in the rack and pinion steering actuator under any circumstances.

[0087] According to the test method of step 2, the steering characteristic data of the vehicle at 5km / h, 10km / h, 20km / h... are measured.

[0088] According to step three, the steering characteristic data of the test vehicle obtained in step two is subjected to linear interpolation and fitting processing to obtain the relationship among the vehicle yaw angular velocity W, the steering wheel angle a1, and the vehicle speed V: W=f1(a1,V).

[0089] According to step 4, the steering response of the vehicle is evaluated and the corresponding working conditions where the steering response needs to be improved are determined. Figure 2 As shown, after the test vehicle in this embodiment is evaluated, when the vehicle is traveling at 60 km / h, the steering wheel angle is 10°, the actuator pinion is 10°, and the vehicle yaw rate is 5° / s, the evaluator believes that the yaw rate of the vehicle is low and needs to be improved, and proposes a goal of increasing the yaw rate by 1.1 times under this condition as an attempt.

[0090] According to step 5, based on the vehicle yaw rate characteristic W = f1(a1,V), we can get W v＝60km / h，a1＝10° =f1(10°,60km / h)=5° / s; 1.1*W v＝60km / h，a1＝10° =5.5° / s Substituting into the yaw rate characteristic W=f3(a,V) yields 1.1*W v＝30km / h，a1＝20° =5.5° / s=f3(a2,60km / h), and a2=12°, that is, the actuator pinion angle to achieve the target yaw should be 12°. After the change is completed, when the steering wheel is 10°, the actuator pinion angle changes from 10° to 12°, that is, the change of the steering gear ratio setting under this working condition is completed.

[0091] After repeatedly executing steps 4 and 5 and completing iterative calibration of various steering conditions, a new W1=f1(a1,V) can be obtained based on the ideal yaw rate calibrated by the test personnel, and W1 is the ideal yaw rate. The calibration software of the steer-by-wire system can be implemented in the above manner, based on W1=f1(a1,V) to calibrate the transmission ratio with the ideal yaw rate as the control target, thus achieving the matching of the transmission ratio of the steer-by-wire system based on the ideal yaw rate.

[0092] Example 2

[0093] Figure 3 This is a schematic diagram of the structure of a computer device in Example 2 of the present invention. Figure 3 A block diagram of an exemplary computer device 12 suitable for use in implementing embodiments of the present invention is shown. Figure 3 The computer device 12 shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present invention.

[0094] like Figure 3As shown, the computer device 12 is in the form of a general-purpose computing device. The components of the computer device 12 may include, but are not limited to: one or more processors or processing units 16, a system memory 28, and a bus 18 that connects various system components (including the system memory 28 and the processing unit 16).

[0095] Bus 18 represents one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, a processor or a local bus using any of a variety of bus architectures. By way of example, these architectures include, but are not limited to, an Industry Standard Architecture (ISA) bus, a Micro Channel Architecture (MAC) bus, an Enhanced ISA bus, a Video Electronics Standards Association (VESA) local bus, and a Peripheral Component Interconnect (PCI) bus.

[0096] The computer device 12 typically includes a variety of computer system readable media. These media can be any available media that can be accessed by the computer device 12, including volatile and non-volatile media, removable and non-removable media.

[0097] The system memory 28 may include computer system readable media in the form of volatile memory, such as random access memory (RAM) 30 and / or cache memory 32. The computer device 12 may further include other removable / non-removable, volatile / non-volatile computer system storage media. By way of example only, the storage system 34 may be used to read and write non-removable, non-volatile magnetic media ( Figure 3 not shown, usually called a "hard drive"). Although Figure 3 Not shown in the figure, a disk drive for reading and writing to a removable non-volatile disk (e.g., a "floppy disk"), and an optical disk drive for reading and writing to a removable non-volatile optical disk (e.g., a CD-ROM, a DVD-ROM, or other optical media) may be provided. In these cases, each drive may be connected to the bus 18 via one or more data medium interfaces. The memory 28 may include at least one program product having a set (e.g., at least one) of program modules that are configured to perform the functions of the various embodiments of the present invention.

[0098] A program / utility 40 having a set (at least one) of program modules 42 may be stored, for example, in the memory 28. Such program modules 42 include, but are not limited to, an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment. The program modules 42 generally perform the functions and / or methods of the embodiments described herein.

[0099] The computer device 12 may also communicate with one or more external devices 14 (e.g., keyboard, pointing device, display 24, etc.), may also communicate with one or more devices that enable a user to interact with the computer device 12, and / or communicate with any device that enables the computer device 12 to communicate with one or more other computing devices (e.g., network card, modem, etc.). Such communication may be performed through an input / output (I / O) interface 22. In addition, the computer device 12 in this embodiment, the display 24 does not exist as an independent individual, but is embedded in the mirror surface, and when the display surface of the display 24 is not displayed, the display surface of the display 24 and the mirror surface are visually integrated. In addition, the computer device 12 may also communicate with one or more networks (e.g., local area network (LAN), wide area network (WAN) and / or public network, such as the Internet) through a network adapter 20. As shown in the figure, the network adapter 20 communicates with other modules of the computer device 12 through a bus 18. It should be understood that although not shown in the figures, other hardware and / or software modules may be used in conjunction with the computer device 12, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems.

[0100] The processing unit 16 executes various functional applications and data processing by running the programs stored in the system memory 28, for example, implementing a transmission ratio matching test method for a passenger vehicle steer-by-wire system provided in an embodiment of the present invention.

[0101] Example 3

[0102] Embodiment 3 of the present invention provides a computer-readable storage medium having a computer program stored thereon. When the program is executed by a processor, a transmission ratio matching test method for a passenger vehicle steer-by-wire system is implemented as provided in all the embodiments of the present application.

[0103] Any combination of one or more computer-readable media may be used. A computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. A computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination thereof. More specific examples (a non-exhaustive list) of computer-readable storage media include: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In this document, a computer-readable storage medium may be any tangible medium containing or storing a program that may be used by or in conjunction with an instruction execution system, device, or device.

[0104] Computer-readable signal media may include a data signal propagated in baseband or as part of a carrier wave, which carries a computer-readable program code. Such propagated data signals may take a variety of forms, including, but not limited to, electromagnetic signals, optical signals, or any suitable combination of the above. Computer-readable signal media may also be any computer-readable medium other than a computer-readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0105] Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

[0106] Computer program code for performing the operations of the present invention may be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0107] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

[0108] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0109] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0110] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A transmission ratio matching test method for a passenger car steer-by-wire system, characterized in that: The specific steps include: Step 1: Test vehicle preparation; Step 2: Vehicle steering characteristics measurement; The vehicle's inertial navigation sensor is used to collect the vehicle's real-time lateral acceleration and yaw rate, and the vehicle's steering wheel angle sensor is used to record the steering wheel angle. The steering characteristics of the test vehicle at different speeds and different steering wheel angles are tested. Step 3: Test data processing; The steering characteristic data obtained from the test is processed to obtain the relationship between the yaw angular velocity W and the steering wheel angle a1 and the vehicle speed V, that is, W = f1 (a1, V); Step 4: The calibration test personnel conduct a subjective evaluation of the vehicle status; Step 5: Transmission ratio calibration; According to the evaluation result in step 4, the target yaw rate W1 is determined. The actuator of the steer-by-wire system determines the new pinion angle a1 required to achieve W1 under the same steering wheel angle a1 according to the relationship between the yaw rate W, the steering wheel angle a1, and the vehicle speed V obtained in step 3: W = f1(a1, V), and the relationship between the steering wheel angle a1 and the steering gear pinion angle a: a1 = f2(a, V). This completes the new transmission ratio matching. Then, steps 4 and 5 are continuously iterated until the yaw rate W executed by the vehicle under various working conditions meets the expectations of the calibrator, that is, the steering transmission ratio matching process is completed by optimizing the characteristics of the vehicle's yaw rate.

2. A transmission ratio matching test method for a passenger car steer-by-wire system as claimed in claim 1, characterized in that: Step 1 specifically includes the following: The vehicle shall be prepared in accordance with the requirements of vehicle maneuverability and stability tests. The vehicle's steer-by-wire system shall have basic steering transmission ratio logic. During steering operation, the speed ratio between the steering wheel rotation and the small gear rotation of the driving rack inside the steering gear shall remain unchanged. The steering wheel angle a1 and the small gear angle a of the rack and pinion steering gear have the following corresponding relationship: a1=f2(a,V).

3. The transmission ratio matching test method of a passenger car steer-by-wire system according to claim 1, characterized in that: In step 2, the vehicle steering characteristic measurement includes a low-speed steering characteristic measurement and a high-speed steering characteristic measurement.

4. A transmission ratio matching test method for a passenger car steer-by-wire system as claimed in claim 3, characterized in that: The low-speed steering characteristic measurement specifically includes the following steps: A1. The test vehicle speed is set to 5km / h, 10km / h, 20km / h, and 30km / h; A2. Keep the vehicle speed at 5 km / h, turn the steering wheel to 5°, 10°, 20°, 30°, 45°, 60°, 90°, 120°, 150°, 180°, 240°, 360° and then keep it fixed. After the vehicle is stable, maintain this state for 3 seconds. A3. When the front wheel grip reaches its limit as the steering wheel angle increases and the vehicle's yaw rate cannot continue to increase, it means that the vehicle's own performance cannot reach a higher yaw rate and the vehicle is in an understeering state. The current steering wheel angle and the corresponding steering actuator position are recorded as the execution upper limit and the measurement is stopped. A4. Increase the test vehicle speed to the next test vehicle speed and repeat steps A2 and A3; A5. Calculate the average yaw rate of the vehicle within 3 seconds in step A2, obtain the relationship between the yaw rate and lateral acceleration corresponding to different steering wheel angles of the vehicle, and fit the relationship between the yaw rate W1 and the steering wheel angle a1 at each vehicle speed as follows: W v＝5km / h =f1(a1),W v＝10km / h =f1(a1),W v＝20km / h =f1(a1),W v＝30km / h =f1(a1).

5. A transmission ratio matching test method for a passenger car steer-by-wire system as claimed in claim 3, characterized in that: The high-speed steering characteristic measurement specifically includes the following steps: B1. The test speed is set to 40km / h, 50km / h, 60km / h, 80km / h, 100km / h, 120km / h, and 150km / h; B2. Maintain the vehicle speed at the test speed + 5; B3. Without applying driving force or braking force, increase the steering wheel angle input from the middle position of the steering wheel to one side at a speed of 20° / s until the vehicle exhibits one of the following two phenomena, indicating that the vehicle cannot stably maintain a higher yaw rate. Record the steering wheel angle and the corresponding steering actuator position when the corresponding phenomenon occurs as the execution upper limit of the current working condition, and perform two measurements on each side; Situation 1: The front axle reaches the grip limit, and the yaw acceleration of the vehicle cannot continue to increase as the steering wheel angle increases, resulting in obvious understeer; Situation 2: The rear axle reaches the grip limit, and as the steering wheel angle increases, the vehicle's turning radius is significantly narrowed or it slips sideways, and it cannot maintain stable driving, and obvious oversteering occurs; B4. Repeat step B3 to increase the steering wheel angle input on the other side and perform two measurements; B5. Increase the vehicle speed to the next test speed and repeat steps A2, A3 and A4; B6. Take the average of the curves of the change relationship between the yaw rate, lateral acceleration and steering wheel angle recorded twice on the left and right sides, and obtain the relationship between the yaw rate W and the steering wheel angle a1 at each vehicle speed: W v＝40km / h =f1(a1),W v＝50km / h =f1(a1),W v＝60km / h =f1(a1)…….

6. A transmission ratio matching test method for a passenger car steer-by-wire system as claimed in claim 1, characterized in that: In step 3, the steering characteristic data obtained from the test is processed, including the following contents: The relationship curves (W) between the yaw angular velocity W obtained in step 2 and the steering wheel angle a1 are v＝5km / h =f1(a1),W v＝10km / h =f1(a1),W v＝20km / h =f1(a1),W v＝30km / h =f1(a1),W v＝40km / h =f1(a1),W v＝50km / h =f1(a1),W v＝60km / h =f1(a1)……) According to the interpolation method, the relationship between W and a1, V is obtained: W=f1(a1,V); according to a1=f2(a,V), W=f3(a,V) is obtained, that is, the relationship between the yaw angular velocity W and the steering actuator pinion angle a and the vehicle speed V.

7. A transmission ratio matching test method for a passenger car steer-by-wire system as claimed in claim 1, characterized in that: Step 4 includes the following: The calibration personnel drive the vehicle from low speed to high speed, and perform parking operations, low-speed maneuvers, turning and changing lanes, and high-speed lane changing conditions; Determine the following: 1) The corresponding working conditions that require changing the steering gear ratio, i.e. the corresponding vehicle speed and steering wheel angle; 2) The difference between the yaw rate of the corresponding working condition and the driver's expectation; 3) Determine the difference between the yaw angular velocity under the corresponding working condition and the yaw angular velocity of the control target.

8. A computer device, characterized in that: The invention comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, a transmission ratio matching test method for a passenger vehicle steer-by-wire system as claimed in any one of claims 1 to 7 is implemented.

9. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the program is executed by a processor, a transmission ratio matching test method for a passenger vehicle steer-by-wire system is implemented as described in any one of claims 1 to 7.

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