Low-temperature compensation control method for electric power steering system, control device and vehicle

Abstract

The application discloses a low-temperature compensation control method and system of an electric power steering system and a vehicle. The control method comprises the following steps: automatically starting the low-temperature compensation control function of the electric power steering system after the vehicle is powered on; obtaining a first temperature value at the meshing position of the worm gear and the worm of the electric power steering system and a second temperature value at the meshing position of the gear and the rack of the electric power steering system; determining the current low-temperature compensation control strategy based on the first temperature value and executing based on the second temperature value and the set time-rotation torque curve. The application determines the current low-temperature compensation control strategy based on the first temperature value to compensate the torque, solves the problem that the vehicle cannot steer or the steering is heavy in a low-temperature environment, improves the steering assistance performance, does not cause torque mutation, and improves the driving safety and the driving experience of the user.

Description

Technical Field

[0001] This invention belongs to the field of electric power steering technology, and more specifically, relates to a low-temperature compensation control method, control device, and vehicle for an electric power steering system. Background Technology

[0002] Due to the significant temperature differences between northern and southern my country, vehicles in northern winters may experience increased friction in the steering system caused by low temperatures. This can lead to performance issues such as abnormal noises at low temperatures, poor self-centering performance at small angles, and a blurred center feel. In low-temperature environments, the increased friction within the steering system can increase steering torque, even causing the vehicle to become unable to steer, or in severe cases, resulting in a lack of power steering. This significantly reduces system safety and the user's driving experience.

[0003] Existing solutions generally reduce the internal friction of the steering system under low-temperature conditions. However, these solutions require improving the machining accuracy of parts and using low-temperature resistant greases, which increases costs and processing difficulty. Furthermore, they cannot completely solve the problem, resulting in a poor customer experience and numerous after-sales complaints.

[0004] The information disclosed in the background section of this invention is intended only to enhance the understanding of the general background of this invention, and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to propose a low-temperature compensation control method, control device, and vehicle for an electric power steering system, thereby solving the problem of the vehicle being unable to steer or having heavy steering in low-temperature environments, and improving driving safety and the user's driving experience.

[0006] To achieve the above objectives, this invention proposes a low-temperature compensation control method, control device, and vehicle for an electric power steering system.

[0007] According to a first aspect of the present invention, a low-temperature compensation control method for an electric power steering system is provided, comprising:

[0008] The low-temperature compensation control function of the electric power steering system is automatically activated after the vehicle is powered on.

[0009] Obtain the first temperature value at the meshing point of the worm wheel and worm in the electric power steering system and the second temperature value at the meshing point of the gear and rack in the electric power steering system.

[0010] The current low-temperature compensation control strategy is determined based on the first temperature value and executed based on the second temperature value and the set time-torque curve.

[0011] Optionally, when Q≥-10°, the first low-temperature compensation control strategy is selected, and low-temperature compensation control is not performed;

[0012] When -10°>Q≥-30°, the second low-temperature compensation control strategy is selected to provide power assistance compensation for the electric power steering system;

[0013] When -30°>Q≥-45°, the third low-temperature compensation control strategy is selected to provide power assistance compensation for the electric power steering system;

[0014] When Q < -45°, the fourth low temperature compensation strategy is selected, and the preheating and pre-start functions of the electric power steering system are activated.

[0015] Where Q is the first temperature value.

[0016] Optionally, the calculation expression for the assist compensation torque of the second cryogenic compensation control strategy is as follows:

[0017] A = T + M + N + G; M = 2% * T;

[0018] When P ≥ -10°, N = 0; when -10° > P ≥ -30°, N = 0.5% * T; when P < -30°, N = 1% * T.

[0019] When V > 60 km / h, G = 0; when V ≤ 60 km / h, G = 0.3% * T;

[0020] Where T is the current basic calibration torque, M is the column compensation torque, N is the steering gear compensation torque, G is the vehicle speed compensation torque, P is the second temperature value, and V is the real-time vehicle speed;

[0021] Optionally, the calculation expression for the assist compensation torque of the third low-temperature compensation control strategy is as follows:

[0022] A = T + M + N + G + K; M = 5% * T;

[0023] When P ≥ -10°, N = 0; when -10° > P ≥ -30°, N = 0.5% * T; when P < 30°, N = 1% * T.

[0024] When the vehicle speed V > 60 km / h, G = 0; when V ≤ 60 km / h, G = 0.5% * T;

[0025] When W > 5 m / s 2 When W = 0.5% * T; when W ≤ 5 m / s 2 When K = 0;

[0026] Where K is the steering wheel angular acceleration compensation torque, and W is the steering wheel angular acceleration.

[0027] Optionally, after activating the preheating start function of the electric power steering system, the starting torque is X = 50% * T, the steering angle is ±3°, and the rotation frequency is 1 time / 3s.

[0028] When Q ≥ -45°, the preheating start function is turned off, and the third low-temperature compensation control strategy is selected; or

[0029] When it is determined that the conditions for driver takeover are met, the preheating start function is turned off, and the third low-temperature compensation control strategy is selected.

[0030] Optionally, the driver takeover conditions include:

[0031] Steering wheel rotation angle > 5° or vehicle speed > 0 km / h.

[0032] Optionally, the current basic calibration torque can be determined based on real-time vehicle speed, steering wheel angle, and basic calibration torque curve.

[0033] Optionally, the first temperature value is obtained based on a first temperature sensor, and the second temperature value is obtained based on a second temperature sensor;

[0034] The first temperature sensor is installed and fixed within 10mm of the meshing point of the worm gear and worm in the electric power steering system, and the second temperature sensor is installed and fixed within 10mm of the meshing point of the gear and rack in the electric power steering system.

[0035] According to a second aspect of the present invention, a low-temperature compensation control device for an electric power steering system is provided, comprising:

[0036] The starting module is used to automatically activate the low-temperature compensation control function of the electric power steering system after the vehicle is powered on.

[0037] The acquisition module is used to acquire the first temperature value at the meshing point of the worm wheel and worm in the electric power steering system and the second temperature value at the meshing point of the gear and rack in the electric power steering system.

[0038] The determination and execution module determines the corresponding low-temperature compensation control strategy based on the first temperature value and executes it based on the set time-torque curve.

[0039] According to a third aspect of the invention, a vehicle is provided, the vehicle including a low-temperature compensation control device for the electric power steering system described in the second aspect.

[0040] The beneficial effects of this invention are as follows: After the vehicle is powered on, the invention automatically activates the low-temperature compensation control function of the electric power steering system, obtains the first temperature value at the meshing point of the worm gear and worm shaft of the electric power steering system and the second temperature value at the meshing point of the gear and rack of the electric power steering system, determines the current low-temperature compensation control strategy based on the first temperature value, and executes the current low-temperature compensation control strategy according to the second temperature value and the set time-torque curve, thereby solving the problem of the vehicle being unable to steer or having heavy steering in low-temperature environments, improving steering assist performance without generating sudden torque changes, and improving driving safety and the user's driving experience.

[0041] The system of the present invention has other features and advantages that will be apparent from or will be set forth in detail in the accompanying drawings and following detailed description, which together serve to explain the particular principles of the invention. Attached Figure Description

[0042] The above and other objects, features and advantages of the present invention will become more apparent from the accompanying drawings, in which like reference numerals generally denote like parts.

[0043] Figure 1 A flowchart illustrating the steps of a low-temperature compensation control method for an electric power steering system according to the present invention is shown.

[0044] Figure 2 A flowchart illustrating the steps of a low-temperature compensation control method for an electric power steering system according to Embodiment 1 of the present invention is shown.

[0045] Figure 3 A basic calibration torque curve according to Embodiment 1 of the present invention is shown.

[0046] Figure 4 A time-torque curve according to Embodiment 1 of the present invention is shown.

[0047] Figure 5 A schematic diagram of a low-temperature compensation control device for an electric power steering system according to Embodiment 2 of the present invention is shown.

[0048] Figure 6 A schematic diagram of the low-temperature compensation control process of a low-temperature compensation control device for an electric power steering system according to Embodiment 2 of the present invention is shown. Detailed Implementation

[0049] The invention will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0050] like Figure 1 As shown, a low-temperature compensation control method for an electric power steering system according to the present invention includes:

[0051] The low-temperature compensation control function of the electric power steering system is automatically activated after the vehicle is powered on.

[0052] Obtain the first temperature value at the meshing point of the worm wheel and worm in the electric power steering system and the second temperature value at the meshing point of the gear and rack in the electric power steering system.

[0053] The current low-temperature compensation control strategy is determined based on the first temperature value and executed based on the second temperature value and the set time-torque curve.

[0054] Specifically, this invention automatically activates the low-temperature compensation control function of the electric power steering system after the vehicle is powered on. It then acquires a first temperature value at the meshing point of the worm gear and worm shaft and a second temperature value at the meshing point of the gear and rack of the electric power steering system, for example, through a temperature sensor. Next, it determines the current low-temperature compensation control strategy based on the first temperature value and executes the strategy according to the second temperature value and a set time-torque curve to compensate for the torque of the electric power steering system. This invention determines the current steering compensation torque based on the second temperature value, and to avoid sudden torque changes, the current torque value transitions to the target torque value according to the set time-torque curve. This invention solves the problem of vehicles being unable to steer or experiencing heavy steering in low-temperature environments, improving steering assist performance without sudden torque changes, thereby enhancing driving safety and the user's driving experience.

[0055] In one example, when Q ≥ -10°, the first low-temperature compensation control strategy is selected, and low-temperature compensation control is not performed;

[0056] When -10°>Q≥-30°, the second low-temperature compensation control strategy is selected to provide power assistance compensation for the electric power steering system;

[0057] When -30°>Q≥-45°, the third low-temperature compensation control strategy is selected to provide power assistance compensation for the electric power steering system;

[0058] When Q < -45°, select the fourth low temperature compensation strategy and activate the preheating and pre-start functions of the electric power steering system.

[0059] Where Q is the first temperature value.

[0060] Specifically, when Q ≥ -10°, the first low-temperature compensation control strategy is selected, and no low-temperature compensation control is performed on the electric power steering system. When -10° > Q ≥ -30°, the second low-temperature compensation control strategy is selected, and the electric power steering system is compensated for using the second low-temperature compensation control strategy. When -30° > Q ≥ -45°, the third low-temperature compensation control strategy is selected, and the electric power steering system is compensated for using the third low-temperature compensation control strategy. When Q < -45°, the fourth low-temperature compensation strategy is selected, which involves activating the preheating and pre-start functions of the electric power steering system. The corresponding low-temperature compensation control strategy is automatically selected based on the first temperature value. For example, when -30° > Q ≥ -45°, the third low-temperature compensation control strategy is selected to compensate for the electric power steering system. When the interior temperature rises and satisfies -10° > Q ≥ -30°, the system automatically switches to the second low-temperature compensation control strategy to compensate for the electric power steering system.

[0061] In one example, the calculation expression for the assist compensation torque of the second cryogenic compensation control strategy is as follows:

[0062] A = T + M + N + G; M = 2% * T;

[0063] When P ≥ -10°, N = 0; when -10° > P ≥ -30°, N = 0.5% * T; when P < -30°, N = 1% * T.

[0064] When V > 60 km / h, G = 0; when V ≤ 60 km / h, G = 0.3% * T;

[0065] Where T is the current basic calibration torque, M is the column compensation torque, N is the steering gear compensation torque, G is the vehicle speed compensation torque, P is the second temperature value, and V is the real-time vehicle speed;

[0066] In one example, the calculation expression for the assist compensation torque of the third cryogenic compensation control strategy is as follows:

[0067] A = T + M + N + G + K; M = 5% * T;

[0068] When P ≥ -10°, N = 0; when -10° > P ≥ -30°, N = 0.5% * T; when P < 30°, N = 1% * T.

[0069] When the vehicle speed V > 60 km / h, G = 0; when V ≤ 60 km / h, G = 0.5% * T;

[0070] When W > 5 m / s2 When W = 0.5% * T; when W ≤ 5 m / s 2 When K = 0;

[0071] Where K is the steering wheel angular acceleration compensation torque, and W is the steering wheel angular acceleration.

[0072] In one example, after activating the preheating start function of the electric power steering system, the starting torque is X = 50% * T, the steering angle is ±3°, and the rotation frequency is 1 time / 3s.

[0073] When Q ≥ -45°, the preheating start function is turned off, and the third low-temperature compensation control strategy is selected; or

[0074] When the conditions for driver takeover are met, the preheating start function is turned off, and the third low-temperature compensation control strategy is selected.

[0075] In one example, the driver takeover conditions include:

[0076] Steering wheel rotation angle > 5° or vehicle speed > 0 km / h.

[0077] In one example, the current base calibration torque is determined based on real-time vehicle speed, steering wheel angle, and the base calibration torque curve.

[0078] Specifically, the base calibration torque is determined by the real-time vehicle speed and steering wheel angle. The base calibration torque curve is plotted based on the real-time vehicle speed, steering wheel angle, and current base calibration torque. The current base calibration torque value in the corresponding base calibration torque curve is adjusted according to the vehicle performance to meet different vehicle performance requirements.

[0079] In one example, a first temperature value is obtained based on a first temperature sensor, and a second temperature value is obtained based on a second temperature sensor.

[0080] The first temperature sensor is installed and fixed within 10mm of the meshing point of the worm gear and worm in the electric power steering system, and the second temperature sensor is installed and fixed within 10mm of the meshing point of the gear and rack in the electric power steering system.

[0081] Specifically, the present invention obtains a first temperature value and a second temperature value through a first temperature sensor and a second temperature sensor, respectively. In order to accurately measure the first temperature value and the second temperature value, the first temperature sensor is installed and fixed within 10mm of the meshing area of ​​the worm gear and worm in the electric power steering system, and the second temperature sensor is installed and fixed within 10mm of the meshing area of ​​the gear and rack in the electric power steering system.

[0082] In one example, when the second low-temperature compensation control strategy is implemented, the low-temperature compensation control function is turned off when Q ≥ -10° for 30 seconds.

[0083] Specifically, during the execution of the second low-temperature compensation control strategy, when the interior temperature rises to Q≥-10°C and lasts for 30 seconds, the low-temperature compensation control function is automatically turned off.

[0084] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the invention. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be combined with each other.

[0085] Example 1

[0086] like Figure 2 As shown, this embodiment provides a low-temperature compensation control method for an electric power steering system, including:

[0087] The low-temperature compensation control function is activated by either unlocking the remote key or IG ON (either condition is sufficient). The system defaults to having the low-temperature compensation control function enabled. This function can be disabled via a soft button on the instrument panel. The low-temperature cold balance controller module acquires the temperature values ​​detected by the embedded temperature sensor I in the column housing and the embedded problem sensor II in the steering gear housing. When Q ≥ -10° (K1 range), no power steering compensation is performed. When -10° > Q ≥ -30° (K2 range), the torque of the electric power steering system is A = T + M + N + G; where T is the basic calibration torque, determined by vehicle speed and steering wheel angle. Figure 3As shown, the horizontal axis represents the steering wheel angle, and the vertical axis represents the basic torque. A, b, c, d, e...n represent different vehicle speed curves. The vehicle speed V is defined as Va>Vb>Vc>Vd>Ve...>Vn (the vehicle speed range is set from 0km / h to 200km / h, and Va=0km / h and Vn=200km / h can be set). Each speed curve is labeled with ①, ②, ③...m to represent different characteristic points. The base torque values ​​at these characteristic points can be adjusted according to vehicle performance to meet different vehicle performance requirements. The curve connecting these characteristic points forms the base torque curve. M is the column compensation torque, M = 2% * T; N is the steering gear compensation torque: when P ≥ -10°, N = 0; when -10° > P ≥ -30°, N = 0.5% * T; when P < -30°, N = 1% * T; G ​​is the speed compensation torque: when vehicle speed V > 60 km / h, G = 0; when V ≤ 60 km / h, G = 0.3% * T. Q is the temperature value detected by temperature sensor I; P is the temperature value detected by temperature sensor II; when -30° > Q ≥ -45° (K3 interval); the torque of the electric power steering system A = T + M + N + G + K, where M = 5% * T; when P ≥ -10°, N = 0; when -10° > P ≥ -30°, N = 0.5% * T; when P < 30°, N = 1% * T; when vehicle speed V > 60 km / h, G = 0; when V ≤ 60 km / h, G = 0.5% * T; K is the steering wheel angular acceleration compensation torque, when the steering wheel angular acceleration W > 5 m / s² 2 When W = 0.5% * T; when W ≤ 5 m / s 2 When Q < -45°, K = 0; when Q < -45° (K4 range), the preheating and pre-start function is activated, and the preheating and pre-start function can be turned on or off by selecting the soft button on the instrument screen; the electric power steering system performs micro-motion preheating and pre-start to reduce the starting torque, the starting torque X = 50% * T, the steering angle is ±3°, and the frequency is 1 time / 3s; when the preheating and pre-start function is executed, the function can be turned off at any time by using the soft button on the instrument screen, and after being turned off, the low temperature compensation strategy when -30° > Q ≥ -45° is adopted; the pre-start function is stopped when the driver takes over the steering wheel. Driver takeover conditions: steering wheel rotation > 5° or vehicle speed > 0 km / h. After takeover, a low-temperature compensation strategy is adopted when -30° > Q ≥ -45°. When Q ≥ -45°, the preheating start function is turned off, and a low-temperature compensation strategy is adopted when -30°Q ≥ -45°. The corresponding compensation torque of the compensation current control is controlled in the transition range of K1, K2, K3, K4. When the current torque value A2 transitions with the target torque value A1, a time interval of T = 10s is used. Figure 4 The curve method is used to smooth the transition, aiming to avoid sudden torque changes; when the Q value is greater than -10° and the duration is 30 seconds, the low temperature compensation control function is deactivated.

[0088] Example 2

[0089] like Figure 5 As shown in this embodiment, a low-temperature compensation control device for an electric power steering system includes:

[0090] The system includes an electric power steering column 1, a temperature sensor embedded in the column housing 2, a temperature sensor embedded in the steering gear housing 3, a rack and pinion steering gear 4, a wiring harness for a temperature sensor embedded in the steering gear housing 5, a wiring harness for a temperature sensor embedded in the column housing 6, and an EPS (Electronic Power Steering) controller 7. Temperature sensors I 2 are embedded in the housing within 10mm of the worm gear and worm meshing area in the electric power steering system, and temperature sensors II 3 are embedded in the housing within 10mm of the gear and rack meshing area. The EPS controller 7 has a built-in low-temperature cold balance control module. The low-temperature compensation control process of this device is as follows: Figure 6As shown, when the remote key unlocks or IG ON transmits the temperature value at the meshing point of the worm gear and worm shaft, obtained by the temperature sensor 2 embedded in the column housing, to the low-temperature cold balance control module of the EPS controller 7 via the temperature sensor harness 5 embedded in the steering gear housing. This temperature value is then sent to the EPS controller 7 for logical judgment to determine the current low-temperature compensation control strategy, which is then sent to the EPS controller 7 to control the motor operation. When the temperature value at the meshing point of the worm gear and worm shaft Q ≥ -10°, no power assist compensation is performed. When -10° > Q ≥ -30°, the torque of the electric power steering system is A = T + M + N + G. Here, T is the basic calibration torque, determined by the vehicle speed and steering wheel angle. The low-temperature cold balance control module obtains the vehicle speed sensor signal from the EPS controller 7 and the steering wheel angle (turn angle) sensor signal from the electric power steering column 1. Based on the vehicle speed sensor signal, steering wheel angle sensor signal, and the basic calibration torque curve, the basic calibration torque is obtained. M is the column compensation torque, M = 2% * T. N is the steering gear compensation torque, obtained by the temperature sensor 3 embedded in the steering gear housing detecting the temperature of the gears and racks. The temperature value at the meshing point is sent to the low-temperature cold balance control module via the temperature sensor wiring harness 5 embedded in the steering gear housing. When the temperature value at the meshing point of the gear and rack is P ≥ -10°, N = 0; when -10° > P ≥ -30°, N = 0.5% * T; when P < -30°, N = 1% * T. G is the vehicle speed compensation torque. When the vehicle speed V > 60 km / h, G = 0; when V ≤ 60 km / h, G = 0.3% * T. When -30° > Q ≥ -45°, the rotation of the electric power steering system... Torque A = T + M + N + G + K, where M = 5% * T; N = 0 when P ≥ -10°; N = 0.5% * T when -10° > P ≥ -30°; N = 1% * T when P < 30°; G = 0 when vehicle speed V > 60 km / h; G = 0 when V ≤ 60 km / h; K is the steering wheel angular acceleration compensation torque. The low-temperature cold balance control module obtains the steering wheel angular acceleration sensor signal from the electric power steering column 1. When the steering wheel angular acceleration W > 5 m / s², the torque is calculated. 2 When W = 0.5% * T; when W ≤ 5 m / s 2When Q < -45°, K = 0; when Q < -45°, the preheating and pre-start function is activated, which can be turned on or off via a soft button on the instrument panel; the electric power steering system performs micro-motion preheating and pre-start to reduce the starting torque, with the starting torque X = 50% * T, a steering angle of ±3°, and a frequency of 1 time / 3s; the preheating and pre-start function can be turned off at any time via a soft button on the instrument panel, and after being turned off, a low-temperature compensation strategy is adopted when -30° > Q ≥ -45°; the preheating and pre-start function is stopped when the driver takes over the steering wheel. Driver takeover conditions: steering wheel rotation > 5° or vehicle speed > 0 km / h, and a low-temperature compensation strategy of -30° > Q ≥ -45° is adopted after taking over; when Q ≥ -45°, the preheating and start function is turned off, and a low-temperature compensation strategy of -30°Q ≥ -45° is adopted; when Q > -10° and the duration is 30s, the low-temperature compensation control function is exited.

[0091] Example 3

[0092] This embodiment provides a vehicle that includes the low-temperature compensation control device for the electric power steering system described in Embodiment 2.

[0093] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A low-temperature compensation control method for an electric power steering system, characterized in that, include: The low-temperature compensation control function of the electric power steering system is automatically activated after the vehicle is powered on. Obtain the first temperature value at the meshing point of the worm wheel and worm in the electric power steering system and the second temperature value at the meshing point of the gear and rack in the electric power steering system. The current low-temperature compensation control strategy is determined based on the first temperature value and executed based on the second temperature value and the set time-torque curve. When Q≥-10°, the first low-temperature compensation control strategy is selected, and low-temperature compensation control is not performed. When -10°>Q≥-30°, the second low-temperature compensation control strategy is selected to provide power assistance compensation for the electric power steering system; When -30°>Q≥-45°, the third low-temperature compensation control strategy is selected to provide power assistance compensation for the electric power steering system; When Q < -45°, the fourth low temperature compensation strategy is selected, and the preheating and pre-start functions of the electric power steering system are activated. Where Q is the first temperature value; The assist compensation torque of the second and third low-temperature compensation control strategies is calculated based on the current basic calibration torque and at least one compensation component. The compensation components include: The string compensation torque is determined based on the current basic calibration torque and the preset proportional coefficient; The steering compensation torque is determined based on the comparison between the second temperature value and the preset temperature threshold. The vehicle speed compensation torque is determined based on the comparison between the real-time vehicle speed and the preset vehicle speed threshold. The steering wheel angular acceleration compensation torque is determined based on the comparison between the steering wheel angular acceleration and the preset acceleration threshold.

2. The low-temperature compensation control method for an electric power steering system according to claim 1, characterized in that, The calculation expression for the assist compensation torque of the second low-temperature compensation control strategy is as follows: A = T + M + N + G; M = 2% * T; When P ≥ -10°, N = 0; when -10° > P ≥ -30°, N = 0.5% * T; when P < -30°, N = 1% * T. When V > 60 km / h, G = 0; when V ≤ 60 km / h, G = 0.3% * T. Where T is the current basic calibration torque, M is the column compensation torque, N is the steering gear compensation torque, G is the vehicle speed compensation torque, P is the second temperature value, and V is the real-time vehicle speed.

3. The low-temperature compensation control method for an electric power steering system according to claim 2, characterized in that, The calculation expression for the assist compensation torque of the third low-temperature compensation control strategy is as follows: A = T + M + N + G + K; M = 5% * T; When P ≥ -10°, N = 0; when -10° > P ≥ -30°, N = 0.5% * T; when P < 30°, N = 1% * T. When the vehicle speed V > 60 km / h, G = 0; when V ≤ 60 km / h, G = 0.5% * T. When W > 5 m / s 2 When W = 0.5% * T; when W ≤ 5 m / s 2 When K=0; Where K is the steering wheel angular acceleration compensation torque, and W is the steering wheel angular acceleration.

4. The low-temperature compensation control method for an electric power steering system according to claim 3, characterized in that, After activating the preheating start function of the electric power steering system, the starting torque is X=50%*T, the steering angle is ±3°, and the rotation frequency is 1 time / 3s. When Q ≥ -45°, the preheating start function is turned off, and the third low-temperature compensation control strategy is selected; or When it is determined that the conditions for driver takeover are met, the preheating start function is turned off, and the third low-temperature compensation control strategy is selected.

5. The low-temperature compensation control method for an electric power steering system according to claim 4, characterized in that, The conditions for driver takeover include: Steering wheel rotation angle > 5° or vehicle speed > 0 km / h.

6. The low-temperature compensation control method for an electric power steering system according to claim 4, characterized in that, The current basic calibration torque is determined based on real-time vehicle speed, steering wheel angle, and basic calibration torque curve.

7. The low-temperature compensation control method for an electric power steering system according to claim 1, characterized in that, The first temperature value is obtained based on the first temperature sensor, and the second temperature value is obtained based on the second temperature sensor; The first temperature sensor is installed and fixed within 10mm of the meshing point of the worm gear and worm in the electric power steering system, and the second temperature sensor is installed and fixed within 10mm of the meshing point of the gear and rack in the electric power steering system.

8. A low-temperature compensation control device for an electric power steering system, used to implement the low-temperature compensation control method according to any one of claims 1-7, characterized in that, include: The starting module is used to automatically activate the low-temperature compensation control function of the electric power steering system after the vehicle is powered on. The acquisition module is used to acquire the first temperature value at the meshing point of the worm wheel and worm in the electric power steering system and the second temperature value at the meshing point of the gear and rack in the electric power steering system. The determination and execution module is used to determine the current low temperature compensation control strategy based on the first temperature value and execute it based on the second temperature value and the set time-torque curve.

9. A vehicle, characterized in that, The vehicle includes a low-temperature compensation control device for the electric power steering system as described in claim 8.

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