Comprehensive driving evaluation method and test system for EPS steering system under low-temperature working condition

Abstract

The invention provides a comprehensive driving evaluation method and test system for an EPS steering system under a low-temperature working condition, and the method comprises the steps: setting a driving evaluation working condition, and carrying out the low-temperature preprocessing of a driving evaluation vehicle according to a temperature condition required by the set driving evaluation working condition; generally, a vehicle to be evaluated is subjected to low-temperature pretreatment; driving or parking according to a preset path and speed required by a set driving evaluation working condition, completing a preset steering action in a driving process to complete a test, collecting sensor data for evaluating steering hand feeling and steering NVH performance, and calculating an objective test result of the EPS steering system under the driving evaluation working condition; and collecting subjective score data of the driver on the steering hand feeling and the steering NVH, and generating a subjective evaluation result of the EPS under the driving evaluation working condition. The driving evaluation method is rich in working condition design, and a more comprehensive and reliable evaluation result can be given by combining subjective and objective data.

Description

Technical Field

[0001] The invention belongs to the technical field of vehicle steering system performance testing, and in particular relates to a comprehensive driving evaluation method and a testing system for an EPS steering system under low temperature conditions. Background Art

[0002] Chassis steering subjective evaluation is one of the most important evaluation indicators of chassis handling performance. It includes many evaluation dimensions. Since previous tests were conducted at room temperature, there were few functional verifications of steering systems and subjective steering evaluations at low temperatures. In addition, traditional steering evaluations were basically based on tests of a single vehicle, and rarely based on multiple models of the same level. In addition, the original tests were conducted on public roads, which posed safety risks and could not provide comprehensive and reliable evaluation results for the vehicle's steering system.

[0003] Invention patent content

[0004] In view of the above problems, the present invention provides a comprehensive driving evaluation method and test system for EPS steering system under low temperature conditions, which greatly enriches the dynamic evaluation of test conditions such as high-adhesion high-speed long straight road, high-adhesion medium-speed multi-bend road, high-adhesion parking car / bad road, low-adhesion parking car, and low-adhesion field, and adds a lot of ice and snow road evaluation, which can combine subjective and objective data to give a more comprehensive and reliable evaluation result. The purpose of the present invention is achieved through the following technical solutions:

[0005] The present invention provides a comprehensive driving evaluation method for an EPS steering system under low temperature conditions, which comprises:

[0006] Set driving review conditions;

[0007] The driving evaluation vehicle is pre-treated at low temperature according to the temperature conditions required by the set driving evaluation working conditions. Usually, the vehicle to be evaluated is pre-treated at low temperature by placing it in a low-temperature warehouse with a fixed temperature or freezing it outdoors in a cold area for a fixed period of time to ensure that the vehicle temperature is at a low temperature before the evaluation.

[0008] The vehicle is driven or parked along the preset path and speed required by the set driving evaluation conditions, and the preset steering action is completed during driving to complete the test, collect sensor data for evaluating steering feel and steering NVH performance, and calculate the objective test results of the EPS steering system under the driving evaluation conditions;

[0009] Collect the driver's subjective rating data on steering feel and steering NVH, and generate the subjective evaluation results of EPS under the driving evaluation conditions;

[0010] A comprehensive score of the EPS steering system in the driving evaluation condition is generated based on the subjective evaluation results and the objective test results. Preferably, the validity of the test data is judged by comparing the subjective evaluation results and the objective test results when generating the comprehensive score, and the results are corrected according to the deviation, and the comprehensive score of the EPS steering system in the condition is output according to the corrected results.

[0011] Furthermore, when calculating the objective test results of the EPS steering system under the driving evaluation conditions, the results for different vehicle models and / or driving modes are adjusted using empirical coefficients.

[0012] Furthermore, the comprehensive driving evaluation method of the present invention selects at least two driving evaluation conditions to complete the test, that is, obtains the comprehensive score of the EPS steering system in at least two conditions; and generates the comprehensive evaluation result of the low-temperature performance of the EPS steering system according to the comprehensive score of the EPS steering system in the at least two conditions.

[0013] Furthermore, the sensor data used to evaluate the steering feel include steering response test signals, steering intermediate feel test signals, steering torque level test signals, and steering return test signals; the sensor data used to evaluate the steering NVH performance include medium and high frequency vibration signals of the steering wheel and medium and high frequency vibration signals of the steering gear.

[0014] Furthermore, the driver's scoring data on steering feel includes an evaluation of at least three parameters of steering comfort, steering road feel, steering response, steering return, steering linearity, steering intermediate feel, steering hand force feel, steering torque and steering viscosity and friction feel; the driver's subjective scoring data on steering NVH includes an evaluation of steering wheel vibration, abnormal steering wheel noise, steering gear vibration and abnormal steering gear noise.

[0015] Furthermore, the driving review working conditions in the method of the present invention include:

[0016] High-adhesion high-speed long straight road driving evaluation working condition: the vehicle is placed outside the first low-temperature room for more than a first preset time for low-temperature pretreatment, and the vehicle is driven on a long straight road with high adhesion without ice and snow where the ambient temperature is lower than the first low temperature, at a driving speed of 100 to 120 km / h; preferably, the first low temperature is -5°C to -15°C, and the first preset time is not less than 6 hours, preferably 8 hours;

[0017] In the high-adhesion, medium-speed and multi-bend driving evaluation condition, the vehicle is placed outdoors for a first preset time or longer for low-temperature pretreatment below the second low temperature, and then driven on a high-adhesion curved road surface with an ambient temperature lower than the second low temperature; the second low temperature is -10℃ to -20℃;

[0018] High adhesion parking / bad road driving evaluation working condition: the vehicle is placed in a low temperature warehouse or outdoors for a first preset time or more below the third low temperature, or in a low temperature warehouse for a second preset time or more below the fourth low temperature for low temperature pretreatment, and the vehicle is parked / driven on a high adhesion road surface with an ambient temperature lower than the third low temperature; the third low temperature is -20℃~-30℃, the fourth low temperature is -30℃~-40℃, the second preset time is not less than 3h, and preferably the second preset time is 4h;

[0019] Low-adhesion parking driving evaluation condition: the vehicle is placed in a low-temperature warehouse or outdoors for a first preset time or below the third low temperature, or in a low-temperature warehouse for a second preset time or below the fourth low temperature for low-temperature pretreatment, and is parked on a low-adhesion ice and snow road with an ambient temperature below -30°C;

[0020] Low-adhesion dynamic driving evaluation conditions: the vehicle is placed in a low-temperature warehouse or outdoors for more than the first preset hour below the third low temperature, or in a low-temperature warehouse for more than the second preset time below the fourth low temperature for low-temperature pretreatment, and is driven in a low-adhesion ice and snow venue with an ambient temperature lower than the third low temperature;

[0021] The fourth low temperature is less than the third low temperature and less than the second low temperature and less than the first low temperature, and the temperature difference between the fourth low temperature and the third low temperature is not less than 8° C.; the first preset time is greater than the second preset time.

[0022] Furthermore, when the high-adhesion, high-speed, long straight road driving evaluation condition is selected for testing, the driver's subjective scoring data on the steering feel under this condition includes the scores of steering response, steering linearity, steering intermediate feel, steering torque, steering return, and steering viscosity and friction.

[0023] Furthermore, when the high-adhesion, medium-speed, multi-bend road driving evaluation condition is selected for testing, the driver's subjective scoring data on the steering feel under this condition includes scores for steering comfort, steering road feel, steering response and steering return.

[0024] Furthermore, when the high-adhesion parking / bad road driving evaluation working condition is selected for testing, the driver's subjective scoring data on the steering feel under this working condition includes the scores of steering force, steering return, steering texture, steering viscosity and friction.

[0025] Furthermore, when the low-attachment parking vehicle driving evaluation condition is selected for testing, the driver's subjective scoring data on the steering feel under this condition includes scores for steering comfort, steering viscosity and friction, and steering return.

[0026] Furthermore, when the low-adhesion field dynamic driving evaluation working condition is selected for testing, the driver's subjective scoring data on the steering feel under this working condition includes the scores of steering comfort, steering feel, steering response and steering return.

[0027] The present invention further provides a comprehensive driving evaluation test system for EPS steering system under low temperature conditions, which includes a driving evaluation vehicle, a sensor system, and a comprehensive evaluation result generating device, wherein the driving evaluation vehicle is equipped with a sensor system, and the comprehensive evaluation result generating device is used to collect sensor data transmitted by the sensor system, collect driver's subjective scoring data, and generate comprehensive evaluation results under different working conditions and a final comprehensive evaluation result. Preferably, the test equipment used by the sensor system includes a steering system test equipment, a vehicle chassis CAN measurement equipment, a noise and vibration test equipment, a temperature measurement equipment, etc.

[0028] Furthermore, the comprehensive evaluation result generating device is provided with a data acquisition module, a single working condition comprehensive score generating module and a low temperature performance comprehensive evaluation result generating module. The data acquisition module has a working condition selection unit, a sensor data acquisition unit and a subjective score collection unit. The working condition selection unit stores a driver's subjective score data form under different working conditions, and pops up the subjective score data form in response to user requirements. After the driver selects or fills in the score value of the corresponding parameter, it is transmitted to the subjective score collection unit; the single working condition comprehensive score generating module generates objective test results and subjective score data according to the data of the sensor data acquisition unit and the subjective score collection unit, and the low temperature performance comprehensive evaluation result generating module generates the final low temperature performance comprehensive evaluation result according to multiple single working condition comprehensive scores.

[0029] The beneficial effects of the present invention are that the present invention is greatly enriched based on different test conditions, covering a variety of conditions such as high-adhesion high-speed long straight road, high-adhesion medium-speed multi-bend road, high-adhesion parking car / bad road, low-adhesion parking car, and low-adhesion site dynamic evaluation, and the subjective evaluation dimension covers many aspects: steering response, steering linearity, steering return, steering intermediate feel, steering torque, etc., which can provide more comprehensive and reliable evaluation data. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Shown is a schematic flow chart of a comprehensive driving evaluation method for a steering system under low temperature conditions of the present invention;

[0031] Figure 2 It is a schematic flow chart of the comprehensive driving evaluation method for comprehensively evaluating the low-temperature working condition of the steering system according to the present invention;

[0032] Figure 3 Shown is a flow chart of vehicle preparation before formal testing of the present invention;

[0033] Figure 4 The figure shows a schematic diagram of a route for testing in Example 3 of the present invention;

[0034] Figure 5 Shown is a schematic diagram of a comprehensive driving evaluation test system in Example 8 of the present invention. DETAILED DESCRIPTION

[0035] The technical scheme of the preferred embodiment of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] Embodiment 1:

[0037] The present invention provides a comprehensive driving evaluation method for an EPS steering system under low temperature conditions, comprising:

[0038] Step S110: setting driving evaluation conditions;

[0039] Step S120: performing low temperature pretreatment on the driving evaluation vehicle according to the temperature conditions required by the set driving evaluation working conditions;

[0040] Step S130: driving or parking the vehicle according to the preset path and speed required by the set driving evaluation condition, completing the preset steering action during driving to complete the test, collecting sensor data for evaluating steering feel and steering NVH performance, and calculating the objective test results of the EPS steering system under the driving evaluation condition;

[0041] Step S140: collecting the driver's subjective rating data on steering feel and steering NVH, and generating a subjective evaluation result of EPS under the driving evaluation condition;

[0042] Step S150: Generate a comprehensive score of the EPS steering system in the driving evaluation condition according to the subjective evaluation results and the objective test results.

[0043] Preferably, in step S150, in order to avoid biased evaluation results due to excessive differences between subjective evaluation and objective data, it is necessary to compare the results to determine the validity of the test data when generating a comprehensive score, and to correct the results according to the deviation.

[0044] In a preferred embodiment, in order to make a more comprehensive and reliable evaluation of the low-temperature performance of the EPS steering system, at least two driving evaluation conditions are selected to complete the test, that is, a comprehensive score of the EPS steering system under at least two conditions is obtained; and a comprehensive evaluation result of the low-temperature performance of the EPS steering system is generated based on the comprehensive score of the EPS steering system under the at least two conditions.

[0045] like Figure 2The illustrated implementation method provides a schematic diagram of a comprehensive driving evaluation process for comprehensively evaluating the low-temperature performance of the EPS steering system. Before the formal test, the vehicle to be evaluated is pre-prepared and the components to be evaluated are assembled on the vehicle to be evaluated and debugged to ensure that the parts of the vehicle to be evaluated are in the correct state. During the formal test, the EPS steering system is tested under five operating conditions, including high-attachment high-speed long straight road driving evaluation, high-attachment medium-speed multi-bend road driving evaluation, high-attachment parking / bad road driving evaluation, low-attachment parking driving evaluation, and low-attachment field dynamic driving evaluation. The comprehensive scores of the EPS steering system under the five operating conditions are obtained, and the final comprehensive evaluation results of the low-temperature performance of the EPS steering system are generated based on the comprehensive scores of the five operating conditions. For the specific test process of the five operating conditions, please refer to the contents of Examples 2 to 6.

[0046] In a specific implementation, the test equipment for the driving review vehicle and its layout and method are as follows: the test equipment mainly includes steering system test equipment, vehicle chassis CAN measurement equipment, noise and vibration test equipment, and temperature measurement equipment. Among them, the steering system test equipment (sensor system) can use CANape, ETAS, etc. The vehicle chassis CAN measurement equipment can be selected from CANoe, VAS6154, etc. The noise and vibration test equipment can be selected from HeadAcoustic, etc., and arranged on the steering wheel and steering gear hardware. The temperature measurement equipment chooses to attach the temperature sensor probe to the steering gear ECU, steering motor, steering gear hardware and other locations, and insert the temperature measurement module Thermo-Scan MiniModul at the other end, connect it to the CANape channel to access the host computer.

[0047] The process of vehicle preparation before formal testing is as follows Figure 3 As shown, it includes vehicle status check, vehicle parts collision check, four-wheel alignment, no-load loading (front axle load is prioritized), tire and tire pressure confirmation based on vehicle configuration and road adhesion, confirmation of correct steering software and hardware versions, and ensuring that the steering mode function is turned on.

[0048] Embodiment 2:

[0049] The principle of this embodiment is the same as that of Embodiment 1. This embodiment provides a process for completing the test under high-adhesion, high-speed, long straight road and low-temperature driving evaluation conditions.

[0050] Low temperature pretreatment: The vehicle is placed outdoors at a temperature below -15°C for more than 8 hours. Disconnect the vehicle battery and test equipment power during the placement period.

[0051] Vehicle starting conditions: ambient temperature below -15°C, ensuring that the vehicle can reach a driving speed of 80kph within 20 minutes.

[0052] Test conditions: high-altitude and long straight roads. Freeways, national roads and high-speed ring test roads without ice and snow are all acceptable.

[0053] Main objective test items:

[0054] Steering feel: ① Steering response, ② Steering center feel, ③ Steering torque, ④ Steering return.

[0055] Steering NVH: ⑤ Steering wheel NVH, ⑥ Steering gear NVH.

[0056] 1. The specific test process of objective testing is as follows:

[0057] (1) Steering feel test:

[0058] (a-1) Steering response test signals: maximum yaw rate (steering wheel sine -25°—+25°), average yaw rate gradient (steering wheel sine -25°—+25°), average lateral acceleration (steering wheel sine -25°—+25°).

[0059] (a-2) Steering response test driving method: Steering wheel sine (-25°—+25°), steering wheel speed (20° / s). Vehicle speed 100km / h, 10 cycles per set, 3 sets. Vehicle speed 120km / h, 10 cycles per set, 3 sets.

[0060] (b-1) Steering middle sense test signal: steering wheel angle (-10°—+10°) established by the torque in the middle area and gradient established by the torque at the edge of the middle area.

[0061] (b-2) Steering center feel test driving method: Steering wheel turns left from 0° to 10°, steering wheel speed (5° / s), steering wheel returns to 0°, the above is 1 left cycle. Then the steering wheel turns right from 0° to 10°, steering wheel speed (5° / s), steering wheel returns to 0°, the above is 1 right cycle. Vehicle speed 100km / h, 10 left cycles 1 group, do 3 groups, 10 right cycles 1 group, do 3 groups. Vehicle speed 120km / h, 0 left cycles 1 group, do 3 groups, 10 right cycles 1 group, do 3 groups.

[0062] (c-1) Steering torque level test signal: 0° steering torque, 10° steering torque, 20° steering torque.

[0063] (c-2) Steering torque horizontal test driving method: Steering wheel sine (-25°—+25°), steering wheel speed (20° / s). Vehicle speed 100km / h, 10 cycles per set, 3 sets. Vehicle speed 120km / h, 10 cycles per set, 3 sets. Combined with the steering response test driving method.

[0064] (d-1) Steering return test signal: average steering wheel return speed, steering overswing times.

[0065] (d-2) Steering return test driving method: Steering 45° step, hold for a moment and then release the steering wheel. Vehicle speed 100km / h, 1 set of 10 cycles on the left side, do 2 sets. Vehicle speed 120km / h, 1 set of 10 cycles on the left side, do 2 sets. Vehicle speed 100km / h, 1 set of 10 cycles on the right side, do 2 sets.

[0066] (2) Steering vibration and noise test:

[0067] (e-1) Medium and high frequency vibration signals of the steering wheel: medium and high frequency vibration frequency, medium and high frequency vibration duration.

[0068] (e-2) Steering wheel medium and high frequency vibration driving method: the above objective test driving + subjective evaluation driving for 10 km.

[0069] (f-1) Steering gear medium and high frequency vibration signals: medium and high frequency vibration frequency, medium and high frequency vibration duration.

[0070] (f-2) Steering medium and high frequency vibration driving method: the above objective test driving + subjective evaluation driving for 10 km. Combined with the steering wheel medium and high frequency vibration driving method.

[0071] (3) Weighted calculation formula for objective test results:

[0072]

[0073] Calculation of the values ​​of each coefficient:

[0074] K _ω_Max : Maximum yaw rate coefficient. The average value of the maximum yaw rate in each of the 30 cycles of 100 km / h, plus the average value of the maximum yaw rate in each of the 30 cycles of 120 km / h, then find the average value, check the empirical value table, and find the corresponding coefficient. The coefficient value is (0-1).

[0075] Average yaw rate gradient coefficient. The average of the absolute values ​​of the yaw rate in each of the 30 cycles at 100 km / h, plus the average of the absolute values ​​of the yaw rate in each of the 30 cycles at 120 km / h, then find the average value, look up the empirical value table, and find the corresponding coefficient. The coefficient value is (0-1).

[0076] K _a_lat_avg: Average lateral acceleration coefficient. The average value of the absolute value of the lateral acceleration in each of the 30 cycles of 100 km / h, plus the average value of the absolute value of the lateral acceleration in each of the 30 cycles of 120 km / h, then find the average value, check the empirical value table, find the corresponding coefficient, the coefficient value is (0-1).

[0077] K _A_cent_avg : Steering angle coefficient in the middle area. The average value of the middle turning angle values ​​of 30 groups of left-cycle measurements at 100km / h, plus the average value of the middle turning angle values ​​of 30 groups of right-cycle measurements, look up the empirical value table to find the corresponding coefficient, and coefficient value 1 is (0-1). The average value of the middle turning angle values ​​of 30 groups of left-cycle measurements at 120km / h, plus the average value of the middle turning angle values ​​of 30 groups of right-cycle measurements, look up the empirical value table to find the corresponding coefficient, and coefficient value 2 is (0-1). The average value of coefficient value 1 and coefficient value 2 is the current coefficient value (0-1).

[0078] K _Grad_avg : The gradient coefficient of the edge moment in the middle of the steering. The average value of the edge moment gradient established by 60 groups of left and right cycle measurements at 100km / h is checked in the empirical value table to find the corresponding coefficient. Coefficient value 1 is (0-1). The average value of the edge moment gradient established by 60 groups of left and right cycle measurements at 120km / h is checked in the empirical value table to find the corresponding coefficient. Coefficient value 2 is (0-1). The average value of coefficient value 1 and coefficient value 2 is the current coefficient value (0-1).

[0079] Average steering torque coefficient. The average torque of each cycle passing through 0° in 30 cycles at 100km / h, plus the average torque of each cycle passing through 0° in 30 cycles at 120km / h, then find the average, check the empirical value table, find the corresponding coefficient, the coefficient value is (0-1).

[0080] Average steering torque coefficient. The average torque of each cycle of 30 cycles at 100km / h over + / -10°, plus the average torque of each cycle of 30 cycles at 120km / h over + / -10°, then find the average, check the empirical value table, find the corresponding coefficient, the coefficient value is (0-1).

[0081] Average steering torque coefficient. The average torque of each cycle of 30 cycles at 100km / h over + / -20°, plus the average torque of each cycle of 30 cycles at 120km / h over + / -20°, then find the average, check the empirical value table, find the corresponding coefficient, the coefficient value is (0-1).

[0082] K _ω_swr_avg: Average steering wheel return speed coefficient. Take the average return speed within + / -40°, check the empirical value table, find the corresponding coefficient, the coefficient value is (0-1). Take the average of the coefficient values ​​of 100km / h and 120km / h, the coefficient value is (0-1).

[0083] K _Num_os : Steering overshoot coefficient. Record the overshoot times of each cycle, and then take the average of all the overshoot times of all the cycles. Take the average of the coefficient values ​​of 100km / h and 120km / h, and this coefficient value is (0-1).

[0084] K _sw_vib :Steering wheel high and medium frequency vibration coefficients. According to the defined high frequency threshold value and medium frequency threshold value, by recording (medium frequency frequency, duration of the medium frequency, high frequency frequency, duration of the high frequency) respectively, check the empirical value table to find the corresponding coefficient, and the coefficient value 1 is (0-1).

[0085] K _gear_vib :Steering gear high and medium frequency vibration coefficients. According to the defined high frequency threshold value and medium frequency threshold value, by recording (medium frequency frequency, duration of the medium frequency, high frequency frequency, duration of the high frequency) respectively, check the empirical value table to find the corresponding coefficient, the coefficient value 1 is (0-1).

[0086] Different choices of vehicle models or driving modes are reflected in the query of the experience value table.

[0087] 2. Main subjective evaluation items:

[0088] (1) Steering feel: steering response, steering linearity, steering center feel, steering torque level, steering return, steering viscosity and friction.

[0089] (2) Steering NVH: various abnormal vibrations and noises of the steering wheel and steering gear.

[0090] Subjective evaluation project introduction:

[0091] (g-1) Steering feel evaluation table:

[0092]

[0093] (g-2) Steering feel evaluation driving method:

[0094] Subjective evaluation: driving 10 km, speed 100-120 km / h.

[0095] (h-1) Steering NVH evaluation table:

[0096]

[0097] (h-2) Steering NVH evaluation driving method:

[0098] Subjective evaluation driving 10km, speed 100-120km / h. Combined with steering feel evaluation driving method.

[0099] (3) Subjective weighted calculation formula:

[0100] S _subj =((hf _1 +hf _2 +hf _3 +hf _4 +hf _5 +hf _6 +hf _7 +hf _8 +hf _9 +hf _10 ) / 60)·0.6+((nvh _1 +nvh _2 +nvh _3 +nvh _4 ) / 40)·0.4

[0101] 3. Comprehensive score of long straight road on Gaofu Expressway

[0102] S _hμ_hv_sr =(S _obj +S _subj )·10·100%

[0103] Compare S _obj With S _subj , if |(S _subj -S _obj ) / S _obj |<0.3, the value is considered valid. Otherwise, re-complete the subjective evaluation and then compare the coefficients. If it is within the range, take the value, otherwise re-complete the objective test and then compare the coefficients.

[0104] Embodiment 3:

[0105] This embodiment provides a process for completing the low temperature performance test of the EPS steering system under high-adhesion, medium-speed, multi-curve and low-temperature driving conditions.

[0106] Low temperature pretreatment of driving evaluation vehicles: The vehicle is placed outdoors at a temperature below -20℃ for more than 8 hours. Disconnect the vehicle battery and test equipment power during the placement period.

[0107] Conditions for starting the vehicle: The ambient temperature is below -20℃ and it is guaranteed to reach the high-speed, medium-speed and winding driving section within 10 minutes.

[0108] Evaluation conditions: high-rise roads with many bends, and mountain bends.

[0109] Driving review route map (one-way or round trip) Figure 4 a- Figure 4 d. The entire route is divided into four sections, and the driving speed of each section is also shown in the figure below. The main routes: S209, G331, Y004 and other sections.

[0110] Driving review route latitude and longitude: Departure point: Longitude: 127.47282, Latitude: 50.26304

[0111] Arrival: Longitude: 126.87689, Latitude: 50.40349

[0112] Paragraph 1, see Figure 4 a: S209(2km)+G331(16.6km)V: 70km / h—80km / h

[0113] Paragraph 2, see Figure 4 b: Y004 (21.4km) V: 60km / h—70km / h

[0114] Paragraph 3, see Figure 4 c: Y004 (21.4km) V: 70km / h—80km / h

[0115] Paragraph 4, see Figure 4 d: Mountain road (13.4km) V: 50km / h—60km / h

[0116] 1. Main objective test items:

[0117] Steering feel: ① steering torque, ② steering response, ③ steering return, ④ steering angle requirement.

[0118] Steering NVH: ⑤ Steering wheel NVH, ⑥ Steering gear NVH.

[0119] (1) Steering feel test:

[0120] (a-1) Steering torque test signal: the duration of the steering torque exceeding the threshold.

[0121] (a-2) Steering torque test driving method: Drive normally and perform normal steering operations according to the vehicle speed of the set road section.

[0122] (b-1) Steering response test signal: duration of yaw rate exceeding threshold, average absolute value of yaw rate, duration of lateral acceleration exceeding threshold, average absolute value of lateral acceleration.

[0123] (b-2) Steering response test driving method: Drive normally and perform normal steering operations at the set speed of the road section.

[0124] (c-1) Steering return test signal: the number of steering return overshoots.

[0125] (c-2) Steering return test driving method: Drive normally and perform normal steering operations according to the vehicle speed set on the road section.

[0126] (d-1) Steering angle requirement test signal: total steering wheel angle, number of steering wheel changes, and maximum steering wheel angle.

[0127] (d-2) Steering angle requirement test driving method: Drive normally and perform normal steering operations according to the vehicle speed of the set road section.

[0128] (2) Steering vibration and noise test:

[0129] (e-1) Medium and high frequency vibration signals of the steering wheel: medium and high frequency vibration frequency, medium and high frequency vibration duration.

[0130] (e-2) Steering wheel medium and high frequency vibration driving method: Drive normally and perform normal steering operations according to the vehicle speed set on the road section.

[0131] (f-1) Steering gear medium and high frequency vibration signals: medium and high frequency vibration frequency, medium and high frequency vibration duration.

[0132] (f-2) Steering gear medium and high frequency vibration driving method: Drive normally and perform normal steering operations according to the vehicle speed set on the road section.

[0133] (3) Weighted calculation formula for objective test results:

[0134]

[0135] Calculation of the values ​​of each coefficient:

[0136] K _Time_tor_lim : Coefficient of duration when the steering torque exceeds the threshold. Based on the threshold selection set in the empirical value table, measure the total duration when the steering torque exceeds the threshold. The duration is inversely proportional to the duration coefficient. Query the corresponding duration coefficient according to the empirical value table. The coefficient value is (0-1).

[0137] V _tar_avg : Target average speed. Preset the target average speed for this trip.

[0138] V _act_avg : Actual average speed. Actual sum of four sections / actual total duration. V not more than 10% _act_avg .

[0139] K _Time_ω_Max_lim: The duration of the yaw rate exceeding the threshold. Based on the threshold selection set in the experience value table, measure the total duration of the yaw rate exceeding the threshold. The duration is proportional to the duration coefficient. Query the corresponding duration coefficient according to the experience value table. The coefficient value is (0-1).

[0140] Average value of yaw rate absolute value. Measure the average value of yaw rate absolute value in all test intervals, and determine the coefficient by looking up the empirical value table. The coefficient value is (0-1).

[0141] K _Time_a_lat_Max_lim :Duration of lateral acceleration exceeding threshold. Based on the threshold selection set in the empirical value table, measure the total duration of lateral acceleration exceeding the threshold. The duration is proportional to the duration coefficient. Query the corresponding duration coefficient according to the empirical value table. The coefficient value is (0-1).

[0142] K _a_lat_avg : The average absolute value of lateral acceleration. Measure the average absolute value of lateral acceleration in all test intervals, and determine the coefficient by looking up the empirical value table. The coefficient value is (0-1).

[0143] K _Num_os : Steering overshoot times coefficient. Measure the steering overshoot times in all test intervals, and determine the coefficient by looking up the empirical value table. The coefficient value is (0-1).

[0144] K _sw_A_total : Total steering wheel angle (considering the driving conditions, the statistics are only calculated when the vehicle speed is above 50km / h). Measure the total steering wheel angle value of all test intervals, and determine the coefficient by looking up the empirical value table. The coefficient value is (0-1).

[0145] K _Num_sw_A_Max :Number of large steering wheel turns (considering the driving conditions, the number is counted only when the vehicle speed is above 50km / h). Based on the threshold selection set in the empirical value table, measure the number of steering wheel turns greater than the threshold in all test intervals, and determine the coefficient by looking up the empirical value table. The coefficient value is (0-1).

[0146] K _Num_sw_change :Number of steering wheel changes (considering the driving conditions, the number is counted only when the vehicle speed is above 50km / h). Measure the number of steering wheel changes in all test intervals, and determine the coefficient by looking up the empirical value table. The coefficient value is (0-1).

[0147] K _sw_vib :Steering wheel high and medium frequency vibration coefficients. According to the defined high frequency threshold value and medium frequency threshold value, by recording (medium frequency frequency, duration of the medium frequency, high frequency frequency, duration of the high frequency) respectively, check the empirical value table to find the corresponding coefficient, and the coefficient value 1 is (0-1).

[0148] K_gear_vib :Steering gear high and medium frequency vibration coefficients. According to the defined high frequency threshold value and medium frequency threshold value, by recording (medium frequency frequency, duration of the medium frequency, high frequency frequency, duration of the high frequency) respectively, check the empirical value table to find the corresponding coefficient, the coefficient value 1 is (0-1).

[0149] The different choices of driving modes are reflected in the query of the experience value table.

[0150] 2. Main subjective evaluation items:

[0151] (1) Steering feel: steering linearity, steering torque, steering texture, steering feedback characteristics, steering response, and steering return.

[0152] (2) Steering NVH: various abnormal vibrations and noises of the steering wheel and steering gear.

[0153] (g-1) Steering feel evaluation table:

[0154]

[0155]

[0156] (g-2) Steering feel evaluation driving method:

[0157] Drive normally and perform normal steering operations according to the set speed of the road section.

[0158] (h-1) Steering NVH evaluation table:

[0159]

[0160] (h-2) Steering NVH evaluation driving method:

[0161] Drive normally and perform normal steering operations according to the set speed of the road section.

[0162] (3) Subjective weighted calculation formula:

[0163] S _subj =((hf _1 +hf _2 +hf _3 +hf _4 +hf _5 +hf _6 +hf _7 +hf _8 ) / 40)·0.7+((nvh _1 +nvh _2 +nvh _3 +nvh _4 ) / 40)·0.3

[0164] 3. Comprehensive rating of driving test on high-speed, medium-speed and winding roads

[0165] S _hμ_mv_cr =(S _obj +S _subj )·10·100%

[0166] Compare S _obj With S _subj , if |(S _subj -S _obj ) / S _obj |<0.3, the value is considered valid. Otherwise, re-complete the subjective evaluation and then compare the coefficients. If it is within the range, take the value, otherwise re-complete the objective test and then compare the coefficients.

[0167] Embodiment 4:

[0168] This embodiment provides a process for completing the low temperature performance test of the EPS steering system under high-adhesion parking / bad road driving conditions.

[0169] Vehicle cold pretreatment: The vehicle is placed in a low-temperature warehouse or outdoors at a temperature below -30℃ for more than 8 hours, or in a low-temperature warehouse or outdoors at a temperature below -40℃ for more than 4 hours. When the vehicle is frozen, open the windows, open the engine hood, and turn off the handbrake. At the same time, disconnect the vehicle battery and the power supply of the test equipment.

[0170] Vehicle start conditions: Ambient temperature is below -30℃, and the vehicle can reach the high-attachment parking / bad road test section within 10 minutes. Drive to the test site with as few turns as possible.

[0171] Evaluation conditions: dry asphalt road, bad road or road with abnormal noise.

[0172] Main objective test items:

[0173] Steering feel: ① Steering torque, ② Steering return.

[0174] Steering NVH: ③ Steering wheel NVH, ④ Steering gear NVH.

[0175] 1. Steering feel test:

[0176] (a-1) Steering torque test signal: in-situ hand force (steering wheel angle 0°, + / -90°, + / -180°, + / -360°), 10km / h hand force (steering wheel angle 0°, + / -90°, + / -180°, + / -360°), 20km / h hand force (steering wheel angle 0°, + / -90°, + / -180°, + / -360°).

[0177] The torque gradient and steering assist coefficient when turning the steering wheel quickly on the spot.

[0178] (a-2) Steering torque test driving method:

[0179] The steering wheel starts from 0°, turns left to the end, then turns right to the end, and then returns to 0°, with the steering wheel speed maintained at 90° / s. The vehicle speeds are 0km / h, 10km / h, and 20km / h. Do this 3 times for each speed.

[0180] In place, turn the steering wheel at the fastest steering wheel speed, with the angle exceeding 90°, and turn it 20 times.

[0181] (b-1) Steering return test signal: average steering wheel return speed (10km / h, 20km / h, 30km / h), steering residual angle value (10km / h, 20km / h, 30km / h).

[0182] (b-2) Steering return test driving method: At a speed of 10km / h, turn the steering wheel to the steering end point, hold it for a moment and then release the steering wheel, do this 3 times. At a speed of 20km / h, turn the steering wheel to 180°, hold it for a moment and then release the steering wheel, do this 3 times. At a speed of 30km / h, turn the steering wheel to 90°, hold it for a moment and then release the steering wheel, do this 3 times.

[0183] (2) Steering vibration and noise test:

[0184] (c-1) Steering wheel medium and high frequency vibration signals: medium and high frequency vibration frequency, medium and high frequency vibration duration.

[0185] (c-2) Steering wheel medium and high frequency vibration driving method:

[0186] Bad road / noise road: Drive in a straight line at a speed of 15km / h.

[0187] Ordinary asphalt road: drive in a straight line at a speed of 15km / h.

[0188] Bad road / noise road: Drive with the steering wheel in a sinusoidal angle (-45°—+45°) at a speed of 15km / h.

[0189] Ordinary asphalt road: Drive with the steering wheel in a sinusoidal angle (-45°—+45°) at a speed of 15km / h.

[0190] (d-1) Steering gear medium and high frequency vibration signals: medium and high frequency vibration frequency, medium and high frequency vibration duration.

[0191] (d-2) Steering gear medium and high frequency vibration driving method: combined with the steering wheel medium and high frequency vibration driving method.

[0192] Road / Noise Road: Drive in a straight line at a speed of 15km / h.

[0193] Ordinary asphalt road: drive in a straight line at a speed of 15km / h.

[0194] Bad road / noise road: Drive with the steering wheel in a sinusoidal angle (-45°—+45°) at a speed of 15km / h.

[0195] Ordinary asphalt road: Drive with the steering wheel in a sinusoidal angle (-45°—+45°) at a speed of 15km / h.

[0196] (3) Weighted calculation formula for objective test results:

[0197] S _obj =((((K _T_0kph +K _T_10kph +K _T_20kph ) / 3)·K _Grad_T_pa ·K _assist ) 1 / 3 0.7+((K _ω_swr_avg_10kph +K _ω_swr_avg_20kph +K _ω_swr_avg_30kph )·(K _A_res_avg_10kph +K _A_res_avg_20kph +K _A_res_avg_30kph )) 1 / 2 ·(1 / 3)·0.3)·0.5+((K _sw_vib_str +K _sw_vib_sin )·0.6+(K _gear_vib_str +K _gear_vib_sin )·0.4)·0.5

[0198] Calculation of the values ​​of each coefficient:

[0199] K _T_0kph :In-situ hand force (0°, + / -90°, + / -180°, + / -360°). Measure the original position, pass through 0°, + / -90°, + / -180°, + / -360°, calculate the average hand force, and then compare and query with the experience value table, calculate the corresponding coefficient, the coefficient value is (0-1).

[0200] K _T_10kph :10km / h hand force (0°, + / -90°, + / -180°, + / -360°). Measure 10kph, pass through 0°, + / -90°, + / -180°, + / -360°, calculate the average hand force, and then compare and query with the experience value table, calculate the corresponding coefficient, the coefficient value is (0-1).

[0201] K _T_20kph:20km / h hand force (0°, + / -90°, + / -180°, + / -360°). Measure 20kph, pass through 0°, + / -90°, + / -180°, + / -360°, calculate the average hand force, and then compare and query with the experience value table, calculate the corresponding coefficient, the coefficient value is (0-1).

[0202] K _Grad_T_pa : The torque gradient of turning the steering wheel quickly in place. Record whether there is a gradient inflection point, record the frequency of the inflection point (non-monotonic slope), find the corresponding empirical value table, and get the coefficient, the coefficient value is (0-1).

[0203] K _assist : Steering assist coefficient. Record the steering assist value. If it is not 100%, select the corresponding value, otherwise the coefficient is 1.

[0204] K _ω_swr_avg_10kph , K _ω_swr_avg_20kph , K _ω_swr_avg_30kph : Average steering wheel return speed (10km / h, 20km / h, 30km / h). Perform return tests at 10km / h, 20km / h, and 30km / h, and take the average return speeds of + / -endpoint, + / -180°, and + / -90°, respectively, and compare them with the empirical value table to calculate the corresponding coefficient, which is (0-1).

[0205] K _A_res_avg_10kph , K _A_res_avg_20kph , K _A_res_avg_30kph : Steering residual angle value (10km / h, 20km / h, 30km / h). Perform the self-centering test at 10km / h, 20km / h, and 30km / h respectively, and calculate the average residual angle of the three tests respectively, and compare them with the empirical value table respectively to calculate the corresponding coefficient, the coefficient value is (0-1).

[0206] K _sw_vib_str : Steering wheel high and medium frequency vibration coefficient (straight line). According to the defined high frequency threshold value and medium frequency threshold value, by recording the two road conditions (medium frequency frequency, the duration of the medium frequency, high frequency frequency, the duration of the high frequency), check the experience value table, find the corresponding coefficient, the coefficient value 1 is (0-1).

[0207] K _sw_vib_sin : Steering wheel high and medium frequency vibration coefficient (sine). According to the defined high frequency threshold value and medium frequency threshold value, by recording the two road conditions (medium frequency frequency, the duration of the medium frequency, high frequency frequency, the duration of the high frequency), check the experience value table, find the corresponding coefficient, the coefficient value 1 is (0-1).

[0208] K _gear_vib_str: Steering gear high and medium frequency vibration coefficient (straight line). According to the defined high frequency threshold value and medium frequency threshold value, by recording the two road conditions (medium frequency frequency, the duration of the medium frequency, high frequency frequency, the duration of the high frequency), check the experience value table, find the corresponding coefficient, the coefficient value 1 is (0-1).

[0209] K _gear_vib_sin :Steering gear high and medium frequency vibration coefficient (sine). According to the defined high frequency threshold value and medium frequency threshold value, by recording the two road conditions (medium frequency frequency, the duration of the medium frequency, high frequency frequency, the duration of the high frequency), check the experience value table, find the corresponding coefficient, the coefficient value 1 is (0-1).

[0210] The different choices of driving modes are reflected in the query of the experience value table.

[0211] 2. Main subjective evaluation items:

[0212] (1) Steering feel: steering force, steering return, steering texture, and steering friction.

[0213] (2) Steering NVH: various abnormal vibrations and noises of the steering wheel and steering gear.

[0214] (e-1) Steering feel evaluation table:

[0215]

[0216] (e-2) Steering feel evaluation driving method:

[0217] The subjective evaluation method is consistent with the objective test driving method, and there is no limit on the number of times.

[0218] (f-1) Steering NVH evaluation table:

[0219]

[0220] (f-2) Steering NVH evaluation driving method:

[0221] The subjective evaluation method is consistent with the objective test driving method, and there is no limit on the number of times.

[0222] (3) Weighted calculation formula for subjective evaluation results:

[0223] S _subj =((hf _1 +hf _2 +hf _3 +hf _4 +hf _5 +hf _6 +hf _7 +hf _8 ) / 50)·0.5+((nvh_1 +nvh _2 +nvh _3 +nvh _4 ) / 40)·0.5

[0224] 3. Comprehensive rating of high-attachment parking / bad road driving test

[0225] S _hμ_lv_pa_br =(S _obj +S _subj )·10·100%

[0226] Compare S _obj With S _subj , if |(S _subj -S _obj ) / S _obj |<0.3, the value is considered valid. Otherwise, re-complete the subjective evaluation and then compare the coefficients. If it is within the range, take the value, otherwise re-complete the objective test and then compare the coefficients.

[0227] Embodiment 5:

[0228] This embodiment provides a process for completing a low temperature performance test of an EPS steering system under a low-attachment parking vehicle driving test condition.

[0229] Vehicle cold pretreatment: The vehicle is placed in a low-temperature warehouse or outdoors at a temperature below -30℃ for more than 8 hours, or in a low-temperature warehouse or outdoors at a temperature below -40℃ for more than 4 hours. When the vehicle is frozen, open the windows, open the engine hood, and turn off the handbrake. At the same time, disconnect the vehicle battery and the power supply of the test equipment.

[0230] Vehicle start conditions: Ambient temperature is below -30℃, and the vehicle can reach the low-attachment parking section within 10 minutes. Drive to the driving test site with as few turns as possible.

[0231] Evaluation conditions: low-adhesion road surface, ice dynamic square, snow dynamic square.

[0232] 1. Main objective test items:

[0233] Steering feel: ① Steering torque, ② Steering return.

[0234] Steering NVH: ③ Steering wheel NVH, ④ Steering gear NVH.

[0235] (1) Steering feel test:

[0236] (a-1) Steering torque test signal: in-situ hand force (0°, + / -90°, + / -180°, + / -360°), 10km / h hand force (0°, + / -90°, + / -180°, + / -360°), 20km / h hand force (0°, + / -90°, + / -180°, + / -360°).

[0237] (a-2) Steering torque test driving method:

[0238] The steering wheel starts from 0°, turns left to the end, then turns right to the end, and then returns to 0°, with the steering wheel speed maintained at 90° / s. The vehicle speeds are 0km / h, 10km / h, and 20km / h, respectively. Do this 3 times for each speed.

[0239] (b-1) Steering return test signal: average steering wheel return speed (10km / h, 20km / h, 30km / h), steering overswing times (10km / h, 20km / h, 30km / h), steering residual angle value (10km / h, 20km / h, 30km / h).

[0240] (b-2) Steering return test driving method: At a speed of 10km / h, turn the steering wheel to the steering end point, hold it for a moment and then release the steering wheel, do this 3 times. At a speed of 20km / h, turn the steering wheel to 180°, hold it for a moment and then release the steering wheel, do this 3 times. At a speed of 30km / h, turn the steering wheel to 90°, hold it for a moment and then release the steering wheel, do this 3 times.

[0241] (2) Steering vibration and noise test:

[0242] (c-1) Steering wheel medium and high frequency vibration signals: medium and high frequency vibration frequency, medium and high frequency vibration duration.

[0243] (c-2) Steering wheel medium and high frequency vibration driving method:

[0244] Snow road: Stay still, steering wheel in sinusoidal direction (0°-left endpoint-right endpoint-0°), rotation speed 90° / s, 180° / s, 360° / s, complete 10 times each.

[0245] Icy road: In place, steering wheel sine (0°-left end point-right end point-0°), speed 90° / s, 180° / s, 360° / s, complete each 10 times.

[0246] Snow road: Drive with the steering wheel in a sinusoidal angle (-45° - +45°) at a speed of 15km / h.

[0247] Icy road: Drive with the steering wheel in a sinusoidal angle (-45° - +45°) at a speed of 15km / h.

[0248] (d-1) Steering gear medium and high frequency vibration signals: medium and high frequency vibration frequency, medium and high frequency vibration duration.

[0249] (d-2) Steering gear medium and high frequency vibration driving method: combined with the steering wheel medium and high frequency vibration driving method.

[0250] Snow road: Stay still, steering wheel in sinusoidal direction (0°-left endpoint-right endpoint-0°), rotation speed 90° / s, 180° / s, 360° / s, complete 10 times each.

[0251] Icy road: In place, steering wheel sine (0°-left end point-right end point-0°), speed 90° / s, 180° / s, 360° / s, complete each 10 times.

[0252] Snow road: Drive with the steering wheel in a sinusoidal angle (-45° - +45°) at a speed of 15km / h.

[0253] Icy road: Drive with the steering wheel in a sinusoidal angle (-45° - +45°) at a speed of 15km / h.

[0254] (3) Weighted calculation formula for objective test results:

[0255] S _obj =(((K _T_0kph +K _T_10kph +K _T_20kph ) / 3)·0.7+((K _ω_swr_avg_10kph +K _ω_swr_avgg_20kph +K _ω_swr_avg_30kph )·(K _Num_os_10kph+ K _Num_os_20kph+ K _Num_os_30kph )·(K _A_res_avg_10kph +K _A_res_avg_20kph +K _A_res_avg_30kph )) 1 / 3 ·(1 / 3)·0.3)·0.5+((K _sw_vib_snow +K _sw_vib_ice )·0.6+(K _gear_vib_snow +K _gear_vib_ice )·0.4)·0.5

[0256] Calculation of the values ​​of each coefficient:

[0257] K _T_0kph :In-situ hand force (0°, + / -90°, + / -180°, + / -360°). Measure the original position, pass through 0°, + / -90°, + / -180°, + / -360°, calculate the average hand force, and then compare and query with the experience value table, calculate the corresponding coefficient, the coefficient value is (0-1).

[0258] K _T_10kph:Hand force (0°, + / -90°, + / -180°, + / -360°). Measure 10km / h, pass through 0°, + / -90°, + / -180°, + / -360°, calculate the average hand force, and then compare and query with the experience value table, calculate the corresponding coefficient, the coefficient value is (0-1).

[0259] K _T_20kph :20km / h hand force (0°, + / -90°, + / -180°, + / -360°). Measure 20km / h, pass through 0°, + / -90°, + / -180°, + / -360°, calculate the average hand force, and then compare and query with the experience value table, calculate the corresponding coefficient, the coefficient value is (0-1).

[0260] K _ω_swr_avg_10kph , K _ω_swr_avg_20kph , K _ω_swr_avg_30kph : Average steering wheel return speed (10km / h, 20km / h, 30km / h). Perform return tests at 10km / h, 20km / h, and 30km / h, and take the average return speeds of + / -endpoint, + / -180°, and + / -90°, respectively, and compare them with the empirical value table to calculate the corresponding coefficient, which is (0-1).

[0261] K _Num_os_10kph , K _Num_os_20kph , K _Num_os_30kph : Steering overshoot times coefficient (10km / h, 20km / h, 30km / h). Record the overshoot times of one cycle, and then take the average of the overshoot times of three cycles. Take the average of the coefficient values ​​of 10km / h, 20km / h, and 30km / h, and this coefficient value is (0-1).

[0262] K _A_res_avg_10kph , K _A_res_avg_20kph , K _A_res_avg_30kph : Steering residual angle value (10km / h, 20km / h, 30km / h). Perform the self-centering test at 10km / h, 20km / h, and 30km / h respectively, and calculate the average residual angle of the three tests respectively, and compare them with the empirical value table respectively to calculate the corresponding coefficient, the coefficient value is (0-1).

[0263] K _sw_vib_snow :Steering wheel high and medium frequency vibration coefficient (snow road). According to the defined high frequency threshold and medium frequency threshold, by recording the (medium frequency frequency, duration of the medium frequency, high frequency frequency, duration of the high frequency) of straight driving and sine operation respectively, check the empirical value table to find the corresponding coefficient, and the coefficient value 1 is (0-1).

[0264] K_sw_vib_ice :Steering wheel high and medium frequency vibration coefficient (icy road). According to the defined high frequency threshold and medium frequency threshold, by recording the (medium frequency frequency, duration of the medium frequency, high frequency frequency, duration of the high frequency) of straight driving and sine operation respectively, check the empirical value table to find the corresponding coefficient, and the coefficient value 1 is (0-1).

[0265] K _gear_vib_snow :Steering gear high and medium frequency vibration coefficient (snow road surface). According to the defined high frequency threshold value and medium frequency threshold value, by recording the (medium frequency frequency, duration of the medium frequency, high frequency frequency, duration of the high frequency) of straight and sinusoidal operation respectively, check the empirical value table to find the corresponding coefficient, and the coefficient value 1 is (0-1).

[0266] K _gear_vib_ice :Steering gear high and medium frequency vibration coefficient (icy road surface). According to the defined high frequency threshold value and medium frequency threshold value, by recording the (medium frequency frequency, duration of the medium frequency, high frequency frequency, duration of the high frequency) of straight and sinusoidal operation respectively, check the empirical value table to find the corresponding coefficient, and the coefficient value 1 is (0-1).

[0267] The different choices of driving modes are reflected in the query of the experience value table.

[0268] 2. Main subjective evaluation items:

[0269] (1) Steering feel: steering comfort, steering viscosity and friction, and steering return.

[0270] (2) Steering NVH: various abnormal vibrations and noises of the steering wheel and steering gear.

[0271] (e-1) Steering feel evaluation table:

[0272]

[0273] (e-2) Steering feel evaluation driving method:

[0274] The subjective evaluation method is consistent with the objective test driving method, and there is no limit on the number of times.

[0275] (f-1) Steering NVH evaluation table:

[0276]

[0277] (f-2) Steering NVH evaluation driving method:

[0278] The subjective evaluation method is consistent with the objective test driving method, and there is no limit on the number of times.

[0279] (3) Weighted calculation formula for subjective evaluation results:

[0280] S_subj =((hf _1 +hf _2 +hf _3 +hf _4 +hf _5 ) / 25)·0.5+((nvh _1 +nvh _2 +nvh _3 +nvh _4 ) / 40)·0.5

[0281] 3. Comprehensive rating of low-attachment parking vehicle driving test

[0282] S _lμ_lv_pa =(S _obj +S _subj )·10·100%

[0283] Compare S _obj With S _subj , if |(S _subj -S _obj ) / S _obj |<0.3, the value is considered valid. Otherwise, re-complete the subjective evaluation and then compare the coefficients. If it is within the range, take the value, otherwise re-complete the objective test and then compare the coefficients.

[0284] Embodiment 6:

[0285] This embodiment provides a process for completing the low temperature performance test of the EPS steering system under low-field dynamic driving evaluation conditions.

[0286] Low temperature pretreatment of the vehicle: The vehicle is placed in a low temperature warehouse or outdoors at a temperature below -30℃ for more than 8 hours, or in a low temperature warehouse or outdoors at a temperature of -40℃ for more than 4 hours. At the same time, disconnect the vehicle battery and the power supply of the test equipment.

[0287] Vehicle start conditions: Ambient temperature is below -30℃, and the vehicle can reach the low-attachment parking section within 10 minutes. Drive to the driving test site with as few turns as possible.

[0288] Evaluation conditions: low-adhesion road surface, ice dynamic square, snow dynamic square.

[0289] 1. Main objective test items:

[0290] Steering feel: ① steering torque, ② steering response, ③ steering return.

[0291] Steering NVH: ③ Steering wheel NVH, ④ Steering gear NVH.

[0292] (1) Steering feel test:

[0293] (a-1) Steering torque test signal:

[0294] Snow Dynamic Square: 40km / h (0°, 20°, 40° steering angle hand force), 60km / h (0°, 15°, 30° steering angle hand force), 80km / h (0°, 10°, 20° steering angle hand force).

[0295] Ice dynamic square: 30km / h (0°, 15°, 30° steering angle hand force)

[0296] R100m snow circle: steering hand force when turning at 95% of the maximum steady-state vehicle speed.

[0297] (a-2) Steering torque test driving method:

[0298] Snow Dynamic Square:

[0299] The vehicle speed is 40km / h, the steering wheel starts from 0°, the sine angle is greater than (-45°—+45°), then returns to 0°, and the steering wheel speed is maintained at 90° / s. Do this 3 times.

[0300] The vehicle speed is 60km / h, the steering wheel starts from 0°, the sine angle is greater than (-35°-+35°), then returns to 0°, and the steering wheel speed is maintained at 90° / s. Do this 3 times.

[0301] The vehicle speed is 80 km / h, the steering wheel starts from 0°, the sine angle is greater than (-25°-+25°), then returns to 0°, and the steering wheel speed is maintained at 90° / s. Do this 3 times.

[0302] Ice Dynamic Square:

[0303] The vehicle speed is 30km / h, the steering wheel starts from 0°, the sine angle is greater than (-35°-+35°), then returns to 0°, and the steering wheel speed is maintained at 90° / s. Do this 3 times.

[0304] R100m snow circle: Steering hand force when turning at 95% of the maximum steady-state vehicle speed, keep it stable for 3 seconds and then record it. Record for 20 seconds and do it 3 times.

[0305] (b-1) Steering response test signal: average steady-state yaw rate, average steady-state lateral acceleration, maximum transient yaw rate, maximum transient lateral acceleration.

[0306] (b-2) Steering response test driving method:

[0307] R100m Snow Circle:

[0308] The steering hand force at 95% of the maximum steady-state vehicle speed is kept stable for 3 seconds and can be recorded. Record for 20 seconds and do it 3 times. Combined with the R100m snow circle in the steering torque test driving method.

[0309] Steering hand force at 95% of maximum steady-state vehicle speed, maintain stability for 3 seconds, add a 3° inward step input, hold for 1 second, return to 0°. Do this 5 times.

[0310] (c-1) Steering return test signal:

[0311] Snow Dynamic Square: average steering wheel return speed (40km / h, 60km / h, 80km / h), steering overswing times (40km / h, 60km / h, 80km / h).

[0312] Ice Dynamic Square: average steering wheel return speed (30km / h), steering overswing times (30km / h).

[0313] (c-2) Steering return test driving method:

[0314] Snow Dynamic Square: At speeds of 40km / h, 60km / h, and 80km / h, turn the steering wheel to 45 degrees, hold for a moment, then release the steering wheel. Do this 3 times.

[0315] Ice Dynamic Square: Drive at 30km / h, turn the steering wheel to 35°, hold for a moment and then release the steering wheel. Do this 3 times.

[0316] (2) Steering vibration and noise test:

[0317] (c-1) Steering wheel medium and high frequency vibration signals: medium and high frequency vibration frequency, medium and high frequency vibration duration.

[0318] (c-2) Steering wheel medium and high frequency vibration driving method:

[0319] Snowy road: Objective test driving as above.

[0320] Icy road: The objective test drive described above.

[0321] (d-1) Steering gear medium and high frequency vibration signals: medium and high frequency vibration frequency, medium and high frequency vibration duration.

[0322] (d-2) Steering gear medium and high frequency vibration driving method: combined with the steering wheel medium and high frequency vibration driving method.

[0323] Snowy road: Objective test driving as above.

[0324] Icy road: The objective test drive described above.

[0325] (3) Objective weighted calculation formula:

[0326] S _obj =(((K _T_40kph_s +K _T_60kph_s +K _T_80kph_s +K _T_30kph_i )·0.5 / 4+K _T_R100_s ·0.5)·0.25+((K _ω_avg ·K _ω_Max ) 1 / 2 0.5+(K _a_lat_avg ·K _a_lat_Max ) 1 / 2 ·0.5)·0.25+((K _ω_swr_avg_40kph_s +K _ω_swr_avg_60kph_s +K _ω_swr_avg_80kph_s +K _ω_swr_avg_30kph_i )·(K _Num_os_40kph_s+ K _Num_os_60kph_s+ K _Num_os_80kph_s +K _Num_os_30kph_i )) 1 / 2 0.25 0.25+((K _sw_vib_snow +K _sw_vib_ice )·0.6+(K _gear_vib_snow +K _gear_vib_ice )·0.4)·0.25

[0327] Calculation of the values ​​of each coefficient:

[0328] K _T_40kph_s : 40km / h (0°, + / -20°, + / -40° steering angle hand force snow road). Measure several points in each cycle of the 40km / h snow road, calculate the average hand force, and then compare it with the empirical value table to calculate the corresponding coefficient, which is (0-1).

[0329] K _T_60kph_s :60km / h (0°, + / -15°, + / -30° steering angle hand force snow road). Measure several points in each cycle of the 60km / h snow road, calculate the average hand force, and then compare it with the empirical value table to calculate the corresponding coefficient, which is (0-1).

[0330] K _T_80kph_s : 80km / h (0°, + / -10°, + / -20° steering angle hand force snow road). Measure several points in each cycle of the 80km / h snow road, calculate the average hand force, and then compare it with the empirical value table to calculate the corresponding coefficient, which is (0-1).

[0331] K _T_30kph_i: 30km / h (0°, + / -15°, + / -30° steering angle hand force ice road). Measure several points in each cycle of the 30km / h ice road, calculate the average hand force, and then compare it with the experience value table to calculate the corresponding coefficient, the coefficient value is (0-1).

[0332] K _T_R100_s : Steering hand force at 95% of the maximum steady-state vehicle speed. Measure the average steering hand force at 95% of the maximum steady-state vehicle speed, and then compare it with the empirical value table. The coefficient value is (0-1).

[0333] K _ω_avg : Average value of steady-state yaw rate. Take the average value of the measured value and compare it with the empirical value table. The coefficient value is (0-1).

[0334] K _a_lat_avg : Average value of steady-state lateral acceleration. Take the average value of the measured value and compare it with the empirical value table. The coefficient value is (0-1).

[0335] K _ω_Max : Maximum value of instantaneous yaw rate. Measure the maximum value and compare it with the empirical value table. The coefficient value is (0-1).

[0336] K _a_lat_Max : Maximum value of transient lateral acceleration. Measure the maximum value and compare it with the empirical value table. The coefficient value is (0-1).

[0337] K _ω_swr_avg_40kph_s : Average steering wheel return speed (40km / h) snowy road. Perform a return test on a 40km / h snowy road, calculate the average return speed from 40° to 0°, compare it with the empirical value table, and calculate the corresponding coefficient, which is (0-1).

[0338] K _ω_ser_avg_60kph_s : Average steering wheel return speed (60km / h) snowy road. Perform a return test on a 60km / h snowy road, calculate the average return speed from 40° to 0°, compare it with the empirical value table, and calculate the corresponding coefficient, which is (0-1).

[0339] K _ω_swr_avg_80kph_s : Average steering wheel return speed (80km / h) snowy road. Perform a return test on a snowy road at 80km / h, calculate the average return speed from 40° to 0°, compare it with the empirical value table, and calculate the corresponding coefficient, which is (0-1).

[0340] K _Num_os_40kph_s: Steering overshoot times (40km / h) on snowy roads. Record the number of overshoots in one cycle, and then take the average of the overshoot times in three cycles. Calculate the coefficient value (0-1) by querying the empirical value table.

[0341] K _Num_os_60kph_s : Steering overshoot times (60km / h) on snowy roads. Record the number of overshoots in one cycle, and then take the average of the overshoot times in three cycles. Calculate the coefficient value (0-1) by querying the empirical value table.

[0342] K _Num_os_80kph_s : Steering overshoot times (80km / h) on snowy roads. Record the number of overshoots in one cycle, and then take the average of the overshoot times in three cycles. Calculate the coefficient value (0-1) by querying the empirical value table.

[0343] K _ω_swr_avg_30kph_i : Average steering wheel return speed (30km / h) icy road. Perform a return test on an icy road at 30km / h, calculate the average return speed from 30° to 0°, compare it with the empirical value table, and calculate the corresponding coefficient, which is (0-1).

[0344] K _Num_os_30kph_i : Steering overshoot times (30km / h) on icy roads. Record the overshoot times in one cycle, and then take the average of the overshoot times in three cycles. Calculate the coefficient value (0-1) by querying the empirical value table.

[0345] K _sw_vib_snow :Steering wheel high and medium frequency vibration coefficient (snow road). According to the defined high frequency threshold and medium frequency threshold, by recording the (medium frequency frequency, duration of the medium frequency, high frequency frequency, duration of the high frequency) of straight driving and sine operation respectively, check the empirical value table to find the corresponding coefficient, and the coefficient value 1 is (0-1).

[0346] K _sw_vib_ice :Steering wheel high and medium frequency vibration coefficient (icy road). According to the defined high frequency threshold and medium frequency threshold, by recording the (medium frequency frequency, duration of the medium frequency, high frequency frequency, duration of the high frequency) of straight driving and sine operation respectively, check the empirical value table to find the corresponding coefficient, and the coefficient value 1 is (0-1).

[0347] K _gear_vib_snow :Steering gear high and medium frequency vibration coefficient (snow road surface). According to the defined high frequency threshold value and medium frequency threshold value, by recording the (medium frequency frequency, duration of the medium frequency, high frequency frequency, duration of the high frequency) of straight and sinusoidal operation respectively, check the empirical value table to find the corresponding coefficient, and the coefficient value 1 is (0-1).

[0348] K _gear_vib_ice:Steering gear high and medium frequency vibration coefficient (icy road surface). According to the defined high frequency threshold value and medium frequency threshold value, by recording the (medium frequency frequency, duration of the medium frequency, high frequency frequency, duration of the high frequency) of straight and sinusoidal operation respectively, check the empirical value table to find the corresponding coefficient, and the coefficient value 1 is (0-1).

[0349] The different choices of driving modes are reflected in the query of the experience value table.

[0350] 2. Main subjective evaluation items:

[0351] (1) Steering feel: steering comfort, steering feel, steering response, and steering return.

[0352] (2) Steering NVH: various abnormal vibrations and noises of the steering wheel and steering gear.

[0353] (e-1) Steering feel evaluation table:

[0354]

[0355]

[0356] (e-2) Steering feel evaluation driving method:

[0357] The subjective evaluation method is consistent with the objective test driving method, and there is no limit on the number of times.

[0358] (f-1) Steering NVH evaluation table:

[0359]

[0360] (f-2) Steering NVH evaluation driving method:

[0361] The subjective evaluation method is consistent with the objective test driving method, and there is no limit on the number of times.

[0362] (3) Weighted calculation formula for subjective evaluation results:

[0363] S _subj =((hf _1 +hf _2 +hf _3 +hf _4 +hf _5 +hf _6 +hf _7 ) / 35)·0.75+((nvh _1 +nvh _2 +nvh _3 +nvh _4 ) / 40)·0.25

[0364] 3. Comprehensive score of low-attachment field dynamic driving evaluation

[0365] S _lμ_pg_dy =(S _obj +S _subj )·10·100%

[0366] Compare S _obj With S _subj , if |(S _subj -S _obj ) / S _obj |<0.3, the value is considered valid. Otherwise, re-complete the subjective evaluation and then compare the coefficients. If it is within the range, take the value, otherwise re-complete the objective test and then compare the coefficients.

[0367] Embodiment 7:

[0368] The basic principle of this embodiment is the same as that of embodiment 1. This embodiment completes the test according to the contents of embodiments 2 to 6, and generates the overall evaluation result of the low temperature performance of the EPS steering system based on its single working condition test and evaluation: S _Total =S _hμ_hv_sr +S _hμ_mv_cr +S _hμ_lv_pa_br +S _lμ_lv_pa +S _lμ_pg_dy

[0369] Where S _Total It is the total score (including objective and subjective). There are five individual items, and the passing score for each item is 12. The passing score for the total score is 70 points. It is used to judge the overall driving performance of the EPS steering system under low temperature conditions. It is also convenient to find the problem items through the individual scores and analyze and solve them in a targeted manner.

[0370] In other implementations, the impact of the following parameters on the test results may be further considered during the test, such as tire pressure, four-wheel alignment parameters, ambient temperature, humidity, wind speed, ECU temperature, voltage (EPS internal, EPS external), battery current, and other CAN signals of interest.

[0371] Embodiment 8:

[0372] The present embodiment provides a comprehensive driving evaluation test system for an EPS steering system under low-temperature conditions, which includes a driving evaluation vehicle 1, a sensor system 2, and a comprehensive evaluation result generating device 3. The driving evaluation vehicle is equipped with a sensor system, and the comprehensive evaluation result generating device is used to collect sensor data transmitted by the sensor system, collect driver's subjective scoring data, and generate comprehensive evaluation results under different working conditions and a final overall evaluation result.

[0373] Preferably, the comprehensive evaluation result generating device 3 is as follows: Figure 5As shown, a data acquisition module 31, a single operating condition comprehensive score generation module 32 and a low temperature performance comprehensive evaluation result generation module 33 are provided: the data acquisition module 31 has an operating condition selection unit, a sensor data acquisition unit and a subjective score collection unit; the operating condition selection unit stores a driver's subjective score data form under different operating conditions, pops up the subjective score data form in response to user requirements, and transmits the score value of the corresponding parameter to the subjective score collection unit after the driver selects or fills in the score value; the single operating condition comprehensive score generation module 32 generates the objective test results and subjective score data under the operating condition according to the data of the sensor data acquisition unit and the subjective score collection unit; the low temperature performance comprehensive evaluation result generation module generates the final low temperature performance comprehensive evaluation result according to multiple single operating condition comprehensive scores.

[0374] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention. The dimensions described in the drawings and embodiments are not related to the specific objects and are not used to limit the protection scope of the present invention. The dimensions of the objects can be selected and changed according to actual needs.

Claims

1. A comprehensive driving evaluation method for EPS steering system under low temperature conditions, comprising: Set driving review conditions; Perform low-temperature pretreatment on the driving evaluation vehicle according to the temperature conditions required by the set driving evaluation working conditions; The vehicle is driven or parked along the preset path and speed required by the set driving evaluation conditions, and the preset steering action is completed during driving to complete the test, collect sensor data for evaluating steering feel and steering NVH performance, and calculate the objective test results of the EPS steering system under the driving evaluation conditions; Collect the driver's subjective rating data on steering feel and steering NVH, and generate the subjective evaluation results of EPS under the driving evaluation conditions; A comprehensive score of the EPS steering system in this driving evaluation condition is generated based on the subjective evaluation results and objective test results.

2. A comprehensive driving evaluation method for EPS steering system under low temperature conditions according to claim 1, characterized in that: Also includes: Select at least two driving test conditions to complete the test. Obtain a comprehensive score of the EPS steering system under at least two operating conditions; A comprehensive evaluation result of the low-temperature performance of the EPS steering system is generated based on the comprehensive score of the EPS steering system under the at least two working conditions.

3. A comprehensive driving evaluation method for EPS steering system under low temperature conditions according to claim 1, characterized in that: The sensor data used to evaluate the steering feel include steering response test signal, steering intermediate feel test signal, steering torque level test signal, and steering return test signal; the sensor data used to evaluate the steering NVH performance include medium and high frequency vibration signals of the steering wheel and medium and high frequency vibration signals of the steering gear.

4. A comprehensive driving evaluation method for EPS steering system under low temperature conditions according to claim 1, characterized in that: The driver's scoring data on steering feel includes the evaluation of at least three parameters among steering comfort, steering road feel, steering response, steering return, steering linearity, steering intermediate feel, steering hand force feel, steering torque and steering viscosity and friction feel; the driver's subjective scoring data on steering NVH includes the evaluation of steering wheel vibration, abnormal steering wheel noise, steering gear vibration and abnormal steering gear noise.

5. A comprehensive driving evaluation method for EPS steering system under low temperature conditions according to any one of claims 1 to 4, characterized in that: The driving evaluation conditions include: High-adhesion high-speed straight road driving evaluation condition: the vehicle is placed outside the first low-temperature room for more than a first preset time for low-temperature pretreatment, and the vehicle is driven on a long straight road with high adhesion and no ice and snow where the ambient temperature is lower than the first low temperature, at a driving speed of 100-120km / h; In the high-adhesion, medium-speed, multi-bend driving evaluation condition, the vehicle is placed outdoors for a first preset time or longer below the second low temperature for low-temperature pretreatment, and then driven on a high-adhesion, bendy road surface with an ambient temperature lower than the second low temperature; High adhesion parking / bad road driving evaluation conditions: the vehicle is placed in a low temperature warehouse below the third low temperature or outdoors for a first preset time or above, or in a low temperature warehouse below the fourth low temperature for a second preset time for low temperature pretreatment, and then parked / driven on a high adhesion road surface with an ambient temperature below the third low temperature; Low-adhesion parking driving evaluation condition: the vehicle is placed in a low-temperature warehouse or outdoors for a first preset time or below the third low temperature, or in a low-temperature warehouse for a second preset time or below the fourth low temperature for low-temperature pretreatment, and is parked on a low-adhesion ice and snow road with an ambient temperature below -30°C; Low-adhesion dynamic driving evaluation conditions: the vehicle is placed in a low-temperature warehouse or outdoors for more than the first preset hour below the third low temperature, or in a low-temperature warehouse for more than the second preset time below the fourth low temperature for low-temperature pretreatment, and is driven in a low-adhesion ice and snow venue with an ambient temperature lower than the third low temperature; The fourth low temperature is less than the third low temperature and less than the second low temperature and less than the first low temperature, and the temperature difference between the fourth low temperature and the third low temperature is not less than 8° C.; the first preset time is greater than the second preset time.

6. A comprehensive driving evaluation method for EPS steering system under low temperature conditions according to claim 5, characterized in that: When the high-adhesion, high-speed, long straight road driving evaluation condition is selected for testing, the driver's subjective scoring data on the steering feel under this condition includes the scores of steering response, steering linearity, steering intermediate feel, steering torque, steering return, and steering viscosity and friction.

7. A comprehensive driving evaluation method for EPS steering system under low temperature conditions according to claim 5, characterized in that: When the high-adhesion, medium-speed, multi-bend road driving evaluation condition is selected for testing, the driver's subjective rating data on the steering feel under this condition includes ratings for steering comfort, steering road feel, steering response and steering return.

8. A comprehensive driving evaluation method for EPS steering system under low temperature conditions according to claim 5, characterized in that: When the high-adhesion parking / bad road driving evaluation condition is selected for testing, the driver's subjective scoring data on the steering feel under this condition includes the scores of steering force, steering return, steering texture, steering viscosity and friction.

9. A comprehensive driving evaluation method for EPS steering system under low temperature conditions according to claim 5, characterized in that: When the low-attachment parking driving evaluation condition is selected for testing, the driver's subjective scoring data on the steering feel under this condition includes the scores for steering comfort, steering viscosity and friction, and steering return.

10. A comprehensive driving evaluation method for EPS steering system under low temperature conditions according to claim 5, characterized in that: When the low-adhesion field dynamic driving evaluation condition is selected for testing, the driver's subjective rating data on the steering feel under this condition includes ratings for steering comfort, steering feel, steering response and steering return.

11. A comprehensive driving evaluation method for EPS steering system under low temperature conditions according to any one of claims 1 to 10, characterized in that: When calculating the objective test results of the EPS steering system under this driving evaluation condition, the results for different vehicle models and / or driving modes are adjusted using empirical coefficients.

12. A comprehensive driving evaluation test system for EPS steering system under low temperature conditions, comprising a driving evaluation vehicle, a sensor system, and a comprehensive evaluation result generating device. The driving evaluation vehicle is equipped with a sensor system, and the comprehensive evaluation result generating device is used to collect sensor data transmitted by the sensor system, collect driver's subjective scoring data and generate comprehensive evaluation results under different working conditions and a final overall evaluation result.

13. A comprehensive driving evaluation test system for EPS steering system under low temperature conditions according to claim 12, characterized in that: The comprehensive evaluation result generating device is provided with a data acquisition module, a single working condition comprehensive score generating module and a low temperature performance comprehensive evaluation result generating module. The data acquisition module has a working condition selection unit, a sensor data acquisition unit and a subjective score collecting unit. The working condition selection unit stores a driver's subjective score data form under different working conditions, pops up the subjective score data form in response to a user's request, and transmits the score value of the corresponding parameter to the subjective score collecting unit after the driver selects or fills in the score value. The single-operating-condition comprehensive score generation module generates objective test results and subjective score data according to the data of the sensor data acquisition unit and the subjective score collection unit, and the low-temperature performance comprehensive evaluation result generation module generates a final low-temperature performance comprehensive evaluation result according to multiple single-operating-condition comprehensive scores.

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