Electric power steering compensation method, controller, steering system, vehicle and medium

Abstract

The invention discloses an electric power steering compensation method, a controller, a steering system, a vehicle and a medium. The method comprises the following steps: acquiring a basic friction compensation torque; determining a self-adaptive friction compensation torque according to a steering wheel torque signal and the basic friction compensation torque; and when the basic friction compensation torque and the self-adaptive friction compensation torque meet preset conditions, a steering mechanism is controlled to work according to the self-adaptive friction compensation torque. According to the method, the friction compensation torque of the steering mechanism can be related to the aging degree of the steering mechanism, smooth and comfortable steering of the steering mechanism can be guaranteed, and then the driving operation stability and safety are guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle driving control, and in particular to an electric power steering compensation method, a controller, a steering system, a vehicle and a medium. Background Art

[0002] With the rapid development of automobile technology, people's requirements for vehicle driving experience are getting higher and higher. As characteristics that affect the sensory experience and personal safety of passengers, vehicle ride comfort and handling stability have received more and more attention. The steering system is the key executive component for the driver to control the vehicle. The smoothness and comfort of the steering system directly determines the safety and handling stability of the entire vehicle. The steering mechanism of the existing steering system has a large friction torque when the vehicle is at low speed, and the steering is stuck and the hand feel is poor during active steering. When actively returning to the center, the return force is insufficient, which is not conducive to returning to the center, but it can effectively suppress vibration and has high handling stability. When the vehicle is at high speed, the moment of inertia is large and the friction torque is small, which makes it easy for the overshoot to increase when returning to the center.

[0003] The friction of the existing steering system mainly comes from the friction between the rack and the pressure block, the friction of the column bearing, etc., which is manifested in the form of Coulomb friction. During the vehicle steering control process, it is generally necessary to look up a table based on the motor speed and apply a force in the same direction of its movement to overcome the Coulomb friction. Due to the aging process of mechanical parts during vehicle use, the friction will change over time, seriously affecting the driver's feel, and thus affecting the steering smoothness and comfort of the steering system. Summary of the invention

[0004] The embodiments of the present invention provide an electric power steering compensation method, a controller, a steering system, a vehicle and a medium to solve the problem that the existing steering system cannot ensure smooth and comfortable steering.

[0005] An electric power steering compensation method, comprising:

[0006] Obtain basic friction compensation torque;

[0007] determining an adaptive friction compensation torque according to the steering wheel torque signal and the basic friction compensation torque;

[0008] When the basic friction compensation torque and the adaptive friction compensation torque meet preset conditions, the steering mechanism is controlled to operate according to the adaptive friction compensation torque.

[0009] Preferably, the obtaining of the basic friction compensation torque comprises:

[0010] Obtaining a steering wheel speed signal, a steering wheel torque signal and a vehicle speed signal;

[0011] A basic friction compensation torque is obtained according to the steering wheel speed signal and the vehicle speed signal.

[0012] Preferably, obtaining a basic friction compensation torque according to the steering wheel speed signal and the vehicle speed signal includes:

[0013] determining a first friction compensation torque and a friction force direction according to the steering wheel speed signal;

[0014] Determining a vehicle speed friction gain and a vehicle speed friction limit according to the vehicle speed signal;

[0015] A basic friction compensation torque is acquired according to the first friction compensation torque, the friction force direction, the vehicle speed friction gain and the vehicle speed friction limit.

[0016] Preferably, obtaining the basic friction compensation torque according to the first friction compensation torque, the friction force direction, the vehicle speed friction gain and the vehicle speed friction limit includes:

[0017] determining a second friction compensation torque according to the first friction compensation torque, the friction force direction and the vehicle speed friction gain;

[0018] The vehicle speed friction limiter is used to limit the amplitude of the second friction compensation torque to obtain a basic friction compensation torque.

[0019] Preferably, the adopting the vehicle speed friction limiter to limit the amplitude of the second friction compensation torque to obtain a basic friction compensation torque includes:

[0020] If the second friction compensation torque is within the vehicle speed friction limit, determining the second friction compensation torque as the basic friction compensation torque;

[0021] If the second friction compensation torque is not within the vehicle speed friction limit, the basic friction compensation torque is determined based on the vehicle speed friction limit.

[0022] Preferably, determining the adaptive friction compensation torque according to the steering wheel torque signal and the basic friction compensation torque comprises:

[0023] When the vehicle is in an active return-to-center condition, trend calculation is performed on the steering wheel torque signal and the calibrated torque signal to determine a target change trend value;

[0024] Determining a target gain coefficient according to the target change trend value;

[0025] An adaptive friction compensation torque is determined according to the target gain coefficient and the basic friction compensation torque.

[0026] Preferably, performing trend calculation on the steering wheel torque signal and the calibration torque signal to determine the target change trend value includes:

[0027] When the vehicle is in an active return-to-center condition, determining a current change trend value corresponding to the steering wheel torque signal according to the steering wheel torque signal and the calibrated torque signal;

[0028] The current change trend value is determined as the target change trend value.

[0029] Preferably, performing trend calculation on the steering wheel torque signal and the calibration torque signal to determine the target change trend value includes:

[0030] Determining a current change trend value corresponding to the steering wheel torque signal according to the steering wheel torque signal and the calibrated torque signal;

[0031] Determine an average change trend value according to all the current change trend values ​​corresponding to this active return to normal working condition;

[0032] Determining a current change trend error according to the current change trend value and the average change trend value;

[0033] If the current change trend error is less than the change trend error threshold, determining the current change trend value as the target change trend value;

[0034] If the current change trend error is not less than the change trend error threshold, the average change trend value is determined as the target change trend value.

[0035] Preferably, determining the target gain coefficient according to the target change trend value includes:

[0036] According to the target change trend value, a trend gain mapping table is searched to determine an original gain coefficient corresponding to the target change trend value;

[0037] The original gain coefficient is amplitude-limited to determine a target gain coefficient.

[0038] Preferably, the amplitude limiting of the original gain coefficient to determine the target gain coefficient includes:

[0039] If the original gain coefficient is less than the preset gain coefficient limit, the original gain coefficient is determined as the target gain coefficient;

[0040] If the original gain coefficient is not less than the preset gain coefficient limit, the target gain coefficient is determined according to the gain coefficient limit.

[0041] Preferably, when the basic friction compensation torque and the adaptive friction compensation torque meet preset conditions, controlling the steering mechanism to work according to the adaptive friction compensation torque includes:

[0042] Determining a target compensation torque error according to the basic friction compensation torque and the adaptive friction compensation torque;

[0043] If the target compensation torque error is not within the compensation torque error threshold, the steering mechanism is controlled to operate according to the adaptive friction compensation torque.

[0044] Preferably, if the target compensation torque error is not within the compensation torque error threshold, controlling the steering mechanism to work according to the adaptive friction compensation torque includes:

[0045] If the target compensation torque error is not within the compensation torque error threshold, obtaining the current vehicle operating condition;

[0046] If the current vehicle operating condition is a safe operating condition, the steering mechanism is controlled to operate according to the adaptive friction compensation torque.

[0047] Preferably, the current vehicle operating condition is determined based on a steering wheel angle signal and a steering wheel torque signal.

[0048] Preferably, the safe operating condition is a condition in which the absolute value of the steering wheel angle signal is less than a preset angle threshold, and the absolute value of the steering wheel torque signal is less than a preset torque threshold.

[0049] A vehicle-mounted controller comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the electric power steering compensation method is implemented.

[0050] A steering system comprises the above-mentioned on-vehicle controller and a steering mechanism connected to the on-vehicle controller.

[0051] A vehicle comprises the above-mentioned steering system.

[0052] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the electric power steering compensation method is implemented.

[0053] The above-mentioned electric power steering compensation method, controller, steering system, vehicle and medium, after obtaining the basic friction compensation torque, adaptively adjust the basic friction compensation torque based on the steering wheel torque signal, so that the adaptive friction compensation torque is related to the aging degree of the steering mechanism; when the basic friction compensation torque and the adaptive friction compensation torque meet the preset conditions, the steering mechanism is controlled according to the adaptive friction compensation torque, so that the friction compensation torque of the steering mechanism is related to the aging degree of the steering mechanism, which helps to ensure the smooth and comfortable steering of the steering mechanism, and thus ensure the driving control stability and safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0055] Figure 1 is a flow chart of an electric power steering compensation method in one embodiment of the present invention;

[0056] Figure 2 is another flow chart of an electric power steering compensation method in one embodiment of the present invention;

[0057] Figure 3 is another flow chart of an electric power steering compensation method in one embodiment of the present invention;

[0058] Figure 4 is another flow chart of an electric power steering compensation method in one embodiment of the present invention;

[0059] Figure 5 is another flow chart of an electric power steering compensation method in one embodiment of the present invention;

[0060] Figure 6 is another flow chart of an electric power steering compensation method in one embodiment of the present invention;

[0061] Figure 7 is another flow chart of an electric power steering compensation method in one embodiment of the present invention;

[0062] Figure 8 is another flow chart of an electric power steering compensation method in one embodiment of the present invention;

[0063] Fig. 9 is another flow chart of an electric power steering compensation method in one embodiment of the present invention;

[0064] Fig.10is another flow chart of an electric power steering compensation method in one embodiment of the present invention;

[0065] Fig.11 is another flow chart of an electric power steering compensation method in one embodiment of the present invention;

[0066] Fig.12 is another flow chart of the electric power steering compensation method in one embodiment of the present invention. DETAILED DESCRIPTION

[0067] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are 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.

[0068] The electric power steering compensation method provided in an embodiment of the present invention can be applied to a vehicle-mounted controller, which is a controller arranged on a vehicle, specifically a controller on a vehicle equipped with an electric power steering system (Electric Power Steering, hereinafter referred to as EPS). It can be a controller dedicated to realizing steering control, or it can be a controller integrated with other functions.

[0069] In one embodiment, if Figure 1 As shown, an electric power steering compensation method is provided, which is described by taking the application of the method in a vehicle-mounted controller as an example, and includes the following steps:

[0070] S101: Obtaining basic friction compensation torque;

[0071] S102: determining an adaptive friction compensation torque according to a steering wheel torque signal and a basic friction compensation torque;

[0072] S103: When the basic friction compensation torque and the adaptive friction compensation torque meet preset conditions, the steering mechanism is controlled to operate according to the adaptive friction compensation torque.

[0073] The basic friction compensation torque is a value determined by calculating the friction compensation torque based on the measured vehicle data collected in real time.

[0074] As an example, in step S101, the on-board controller can obtain the measured vehicle data sent in real time by the bus or other sensors during the vehicle driving process, for example, when the vehicle is in an active return condition; then, the measured vehicle data is calculated using the pre-set basic friction compensation torque calculation logic to obtain the calculated basic friction compensation torque. The basic friction compensation torque calculation logic here is a pre-set processing logic for calculating the basic friction compensation torque, which can be a processing logic in the prior art.

[0075] As an example, in step S102, after obtaining the basic friction compensation torque, the on-board controller can determine the change in friction due to structural aging based on the steering wheel torque signal analysis, and based on the change, determine the target gain coefficient that needs to be adjusted for the basic friction compensation torque; then, the basic friction compensation torque is gain-adjusted based on the target gain coefficient to obtain the gained adaptive friction compensation torque, so that the adaptive friction compensation torque is related to the degree of aging of the steering mechanism, so that when the steering mechanism is controlled based on the adaptive friction compensation torque, the steering system can be ensured to be smooth and comfortable.

[0076] The preset condition is a pre-set condition used to evaluate whether adaptive compensation can be performed.

[0077] As an example, in step S103, after respectively obtaining the basic friction compensation torque and the adaptive friction compensation torque, the on-board controller can evaluate whether the preset conditions are met based on the basic friction compensation torque and the adaptive friction compensation torque; when the preset conditions are met, the steering mechanism is controlled to work according to the adaptive friction compensation torque, that is, when the preset conditions are met, the adaptive friction compensation torque is determined as the target friction compensation torque, and the steering mechanism is controlled to work according to the target friction compensation torque; when the preset conditions are not met, the steering mechanism is controlled to work according to the basic friction compensation torque, that is, when the preset conditions are not met, the basic friction compensation torque is determined as the target friction compensation torque, and the steering mechanism is controlled to work according to the target friction compensation torque.

[0078] In this example, after determining the target friction compensation torque, the onboard controller can determine the corresponding target control current based on the target friction compensation torque, so as to control the operation of the motor of the steering mechanism based on the target control current. In this example, the onboard controller can combine the determined target friction compensation torque with other compensation torques or power torques into basic power assistance, and send it to the motor control module of the steering mechanism in the form of instructions to control the rotation of the motor of the steering mechanism, act on the steering mechanism, and provide the driver with steering assistance.

[0079] In one example, the operation of the steering mechanism is controlled according to the target friction compensation torque, including: (1) determining the basic power assist according to the target friction compensation torque; (2) determining the power assist control current according to the basic power assist; (3) determining the target control current according to the power assist control current and the motor feedback current, and controlling the operation of the steering mechanism based on the target control current.

[0080] As an example, when determining the target friction compensation torque, the on-board controller can determine the friction compensation assist according to the target friction compensation torque, and then determine the combined force of the friction compensation assist, basic torque assist, active return assist, sway damping and inertia compensation as the basic assist.

[0081] As an example, after determining the basic power assist, the on-board controller may determine the corresponding power assist control current based on the basic power assist. Specifically, the power assist control current corresponding to the basic power assist may be determined based on a basic power assist table lookup or other control methods.

[0082] As an example, when the on-board controller determines the power-assist control current corresponding to a certain moment, at the initial moment, the power-assist control current can be determined as the target control current to control the motor operation of the steering mechanism. During the rotation of the motor of the steering mechanism, the motor feedback current will be output; after the initial moment, the power-assist control current is compared with the motor feedback current of the motor feedback in the steering mechanism, and a new target control current is output to control the motor operation of the steering mechanism based on the new target control current, so that the force output by the motor is equal to the torque corresponding to the basic power-assist, so as to achieve steering control. In this example, the on-board controller outputs the target control current to control the rotation of the motor, and the motor feedback current is used for feedback control of the motor controller to prevent the motor from outputting uncontrollable torques such as excessive or too small.

[0083] In this embodiment, after obtaining the basic friction compensation torque, the basic friction compensation torque is adaptively adjusted based on the steering wheel torque signal, so that the adaptive friction compensation torque is related to the aging degree of the steering mechanism; when the basic friction compensation torque and the adaptive friction compensation torque meet the preset conditions, the steering mechanism is controlled according to the adaptive friction compensation torque, so that the friction compensation torque of the steering mechanism is related to the aging degree of the steering mechanism, which helps to ensure smooth and comfortable steering of the steering mechanism, and thus ensure driving control stability and safety.

[0084] In one embodiment, if Figure 2 As shown, step S101, i.e. obtaining the basic friction compensation torque, includes:

[0085] S201: Acquire a steering wheel speed signal, a steering wheel torque signal, and a vehicle speed signal;

[0086] S202: Obtaining a basic friction compensation torque according to a steering wheel speed signal and a vehicle speed signal.

[0087] The steering wheel speed signal refers to a signal reflecting the steering wheel speed collected in real time, which can be represented by ω. The steering wheel torque signal refers to a signal reflecting the steering wheel torque collected in real time, which can be represented by T. The vehicle speed signal refers to a vehicle speed signal collected in real time, which can be represented by V.

[0088] As an example, in step S201, the on-board controller can obtain the steering wheel speed signal ω and the steering wheel torque signal T sent by the torque angle sensor loaded on the vehicle during the vehicle driving process, for example, when the vehicle is in the active return working condition, and obtain the measured vehicle data such as the vehicle speed signal V sent by the bus, so as to perform friction torque compensation processing based on these measured vehicle data. Generally speaking, a torque angle sensor is arranged on the steering shaft of the vehicle steering system, which can be but not limited to a Tas sensor. The torque angle sensor can collect the steering wheel angle signal A, perform differential processing on the steering wheel angle signal A, and obtain the steering wheel speed signal ω; then, according to the relationship between power, speed and torque, the steering wheel speed signal ω is analyzed to obtain the steering wheel torque signal T, and the steering wheel speed signal ω and the steering wheel torque signal T are sent to the on-board controller. In this example, the steering wheel speed signal ω, the steering wheel torque signal T and the vehicle speed signal V are all signals that need to be collected during the vehicle driving process, and can be directly called in the friction torque compensation process, without the need to set up additional sensors for measurement, which helps to save costs.

[0089] As an example, in step S202, the on-board controller may use the pre-set basic friction compensation torque calculation logic to calculate the two input parameters of the steering wheel speed signal ω and the vehicle speed signal V collected in real time to obtain the calculated basic friction compensation torque. Since the compensation value of the friction torque is correlated with the motor speed, and the steering mechanism in the steering system is mechanically connected to the steering wheel, so that the motor speed and the steering wheel speed signal ω have a positive correlation, therefore, the steering wheel speed signal ω needs to be used as an input parameter to calculate the basic friction compensation torque; since the steering mechanism has a large friction torque when the vehicle is traveling at a low speed, and the steering mechanism has a small friction torque when the vehicle is traveling at a high speed, therefore, the vehicle speed signal V needs to be used as an input parameter to calculate the basic friction compensation torque. In this example, the basic friction compensation torque calculation logic is a calculation logic determined in advance based on the correlation between the friction torque and the steering wheel speed signal ω and the vehicle speed signal V, and the steering wheel speed signal ω and the vehicle speed signal V are used as input parameters, and the corresponding friction torque calculation logic is determined by table lookup or mathematical operation, and the calculation process is simple and convenient.

[0090] For example, a friction compensation torque can be determined based on a table lookup or other conversion processing based on the steering wheel speed signal ω, and then the determined friction compensation torque can be adjusted in real time using the vehicle speed signal V to obtain a basic friction compensation torque. The determined basic friction compensation torque is not only related to the steering wheel speed signal ω, but also to the vehicle speed signal V, so as to adapt to the different needs of the vehicle when driving at low speed or high speed, which is beneficial to ensuring the handling stability and safety of the vehicle.

[0091] In the present embodiment, the steering wheel speed signal, steering wheel torque signal and vehicle speed signal collected by the vehicle's existing hardware equipment are utilized, and there is no need to set up additional sensors to measure related data, which helps to save costs; based on the steering wheel speed signal and the vehicle speed signal, the basic friction compensation torque is obtained, so that the basic friction compensation torque is not only related to the steering wheel speed, but also to the vehicle speed, which can adapt to the different needs of low-speed driving or high-speed driving, and helps to ensure driving control stability and safety.

[0092] In one embodiment, if Figure 3 As shown, step S202, i.e. obtaining a basic friction compensation torque according to a steering wheel speed signal and a vehicle speed signal, comprises:

[0093] S301: determining a first friction compensation torque and a friction force direction according to a steering wheel speed signal;

[0094] S302: Determine a vehicle speed friction gain and a vehicle speed friction limit according to the vehicle speed signal;

[0095] S303: Obtain a basic friction compensation torque according to the first friction compensation torque, the friction force direction, the vehicle speed friction gain, and the vehicle speed friction limit.

[0096] The first friction compensation torque refers to the friction compensation torque directly determined according to the steering wheel speed signal ω, which can be represented by WheelSpdCtor. The friction force direction refers to the direction corresponding to the friction force determined according to the steering wheel speed signal ω, which can be represented by SingWheelSpd.

[0097] As an example, in step S301, after acquiring the steering wheel speed signal ω, the onboard controller may process the steering wheel speed signal ω according to a preset speed-friction compensation torque mapping function, and may quickly determine the first friction compensation torque WheelSpdCtor corresponding to the steering wheel speed signal ω; or. The onboard controller may query a preset speed-friction compensation torque mapping table based on the first friction compensation torque WheelSpdCtor, and may quickly determine the first friction compensation torque WheelSpdCtor corresponding to the steering wheel speed signal ω. Since the compensation value of the friction torque is correlated with the motor speed, and the steering mechanism in the steering system is mechanically connected to the steering wheel, the motor speed is positively correlated with the steering wheel speed signal ω, that is, the compensation value of the friction torque is positively correlated with the steering wheel speed signal ω. Based on the positive correlation, a speed-friction compensation torque mapping function or a speed-friction compensation torque mapping table is constructed in advance, so as to perform function calculation or table lookup based on the steering wheel speed signal ω, and quickly determine the corresponding first friction compensation torque WheelSpdCtor. Accordingly, the vehicle controller can also determine the steering wheel rotation direction of the steering wheel speed signal ω, and then determine the steering force direction according to the determined steering wheel rotation direction, and then determine the corresponding friction force direction SingWheelSpd. Since the function calculation or table lookup process of the steering wheel speed signal ω is generally based on the absolute value of the steering wheel speed signal ω, the calculated first friction compensation torque WheelSpdCtor does not include the friction force direction. Therefore, it is necessary to determine the corresponding friction force direction SingWheelSpd based on the steering wheel speed signal ω.

[0098] The vehicle speed friction gain FCGaid refers to a coefficient for adjusting the gain of the friction compensation torque according to the vehicle speed signal V, which can be expressed by FCGaid. The vehicle speed friction limit FCLimit refers to a threshold for limiting the amplitude of the friction compensation torque according to the vehicle speed signal V.

[0099] As an example, in step S302, after acquiring the vehicle speed signal V, the on-board controller may process the vehicle speed signal V according to the pre-set vehicle speed-friction gain mapping function, and may quickly determine the vehicle speed friction gain FCGaid corresponding to the vehicle speed signal V. Alternatively, the on-board controller may query the pre-set vehicle speed-friction gain mapping table based on the vehicle speed signal, and may quickly determine the vehicle speed friction gain FCGaid corresponding to the vehicle speed signal V. Since the steering mechanism has a large friction torque when the vehicle is traveling at a low speed, and the steering mechanism has a small friction torque when the vehicle is traveling at a high speed, it can be known that the friction torque has a negative correlation with the vehicle speed signal V. Based on the negative correlation, a vehicle speed-friction gain mapping function or a vehicle speed-friction gain mapping table is constructed in advance, so that a function calculation or table lookup is performed based on the vehicle speed signal V, and the corresponding vehicle speed friction gain FCGaid can be quickly determined, so that the vehicle speed friction gain FCGaid is used to adjust the gain of the first friction compensation torque WheelSpdCtor determined based on the steering wheel speed signal ω, so as to achieve real-time adjustment of the friction compensation torque based on the vehicle speed signal V.

[0100] Accordingly, after acquiring the vehicle speed signal V, the on-board controller can process the vehicle speed signal V according to the preset vehicle speed-friction limit mapping function, and can quickly determine the vehicle speed friction limit FCLimit corresponding to the vehicle speed signal V. Alternatively, the on-board controller can query a preset vehicle speed-friction limit mapping table based on the vehicle speed signal, and can quickly determine the vehicle speed friction limit FCLimit corresponding to the vehicle speed signal V. The friction torque has a negative correlation with the vehicle speed signal V. When the friction torque is large, the steering is stuck and the hand feeling is poor during active steering. When the vehicle is actively returning to the center, the return force is insufficient, which is not conducive to returning to the center. When the friction torque is small, the overshoot is easy to increase during the return to the center, that is, the friction torque must be within a specific range to ensure the safety and handling stability of the vehicle. Therefore, a vehicle speed-friction limit mapping function or a vehicle speed-friction limit mapping table can be pre-constructed to perform function calculation or table lookup based on the vehicle speed signal V, and the corresponding vehicle speed friction limit FCLimit can be quickly determined, so that the vehicle speed friction limit FCLimit can be used to limit the amplitude of the friction compensation torque based on the vehicle speed signal V to ensure the safety and handling stability of the vehicle. Generally speaking, the size of the vehicle speed friction limit FCLimit is given by calibration and comprehensive consideration of driving safety.

[0101] As an example, in step S303, after obtaining the first friction compensation torque WheelSpdCtor and the friction force direction SingWheelSpd corresponding to the steering wheel speed signal ω, and obtaining the vehicle speed friction gain FCGaid and the vehicle speed friction limit FCLimit corresponding to the vehicle speed signal V, the on-board controller can calculate and process the input parameters such as the first friction compensation torque WheelSpdCtor, the friction force direction SingWheelSpd, the vehicle speed friction gain FCGaid and the vehicle speed friction limit FCLimit based on the pre-set basic friction compensation torque determination logic to determine its output basic friction compensation torque. For example, the on-board controller can adjust the gain of the first friction compensation torque WheelSpdCtor based on the vehicle speed friction gain FCGaid, and then use the vehicle speed friction limit FCLimit to limit the amplitude of the friction compensation torque after the gain adjustment to obtain the magnitude of the basic friction compensation torque; and obtain the direction of the basic friction compensation torque according to the friction force direction SingWheelSpd.

[0102] In this embodiment, the steering wheel speed signal ω determines its corresponding first friction compensation torque and friction force direction, and determines its corresponding vehicle speed friction gain FCGaid and vehicle speed friction limit FCLimit based on the vehicle speed signal, so that the vehicle speed friction gain FCGaid can be used to adjust the gain of the first friction compensation torque, and the vehicle speed friction limit FCLimit can be used to limit the amplitude of the friction compensation torque after the gain adjustment. The friction compensation torque determined based on the steering wheel speed signal ω can be adjusted in real time according to the vehicle speed signal V, so that the determined basic friction compensation torque is not only related to the steering wheel speed signal ω, but also related to the vehicle speed signal V, so as to adapt to the different needs of the vehicle under low-speed driving or high-speed driving, which is beneficial to ensuring the driving stability and safety of the vehicle.

[0103] In one embodiment, if Figure 4 As shown, step S303, i.e., obtaining a basic friction compensation torque according to the first friction compensation torque, the friction force direction, the vehicle speed friction gain and the vehicle speed friction limit, comprises:

[0104] S401: determining a second friction compensation torque according to the first friction compensation torque, the friction force direction and the vehicle speed friction gain;

[0105] S402: Using a vehicle speed friction limiter to limit the amplitude of the second friction compensation torque to obtain a basic friction compensation torque.

[0106] As an example, in step S401, after obtaining the first friction compensation torque WheelSpdCtor and the friction force direction SingWheelSpd corresponding to the steering wheel speed signal ω, and obtaining the vehicle speed friction gain FCGaid corresponding to the vehicle speed signal V, the vehicle controller can determine the product of the first friction compensation torque WheelSpdCtor, the friction force direction SingWheelSpd and the vehicle speed friction gain FCGaid as the second friction compensation torque. That is, the second friction compensation torque refers to the friction compensation torque after the direction is determined based on the friction force direction SingWheelSpd, and the vehicle speed friction gain FCGaid is used to adjust the gain of the first friction compensation torque WheelSpdCtor determined based on the steering wheel speed signal ω, which can be understood as the value after the friction compensation torque is gain-adjusted based on the vehicle speed signal V.

[0107] As an example, in step S402, after determining the second friction compensation torque, the on-board controller may limit the amplitude of the second friction compensation torque according to the vehicle speed friction limit FCLimit corresponding to the vehicle speed signal V, so as to ensure that the basic friction compensation torque finally outputted is within the safety range limited by the vehicle speed friction limit FCLimit corresponding to the vehicle speed signal V, which helps to ensure driving safety.

[0108] In this embodiment, the vehicle speed friction gain FCGaid determined based on the vehicle speed signal V is used to perform gain adjustment on the first friction compensation torque WheelSpdCtor determined based on the steering wheel speed signal ω to determine the second friction compensation torque, so as to achieve real-time adjustment of the friction compensation torque based on the vehicle speed signal V to ensure driving safety and handling stability; the vehicle speed friction limit FCLimit determined based on the vehicle speed signal V is used to limit the second friction compensation torque to ensure that the basic friction compensation torque outputted is within a preset safety range, which helps to ensure driving safety and handling stability.

[0109] In one embodiment, if Figure 5 As shown, step S402, i.e., using the vehicle speed friction limiter to limit the amplitude of the second friction compensation torque to obtain the basic friction compensation torque, includes:

[0110] S501: if the second friction compensation torque is within the vehicle speed friction limit, determining the second friction compensation torque as the basic friction compensation torque;

[0111] S502: If the second friction compensation torque is not within the vehicle speed friction limit, a basic friction compensation torque is obtained based on the vehicle speed friction limit.

[0112] Among them, the vehicle speed friction limit is a limit range of the friction compensation torque determined based on the vehicle speed signal V, including the lower limit of the vehicle speed friction compensation torque and the upper limit of the vehicle speed friction compensation torque. The lower limit of the vehicle speed friction compensation torque refers to the lower limit value of the friction compensation torque determined according to the vehicle speed signal V, and the upper limit of the vehicle speed friction compensation torque refers to the upper limit value of the friction compensation torque determined according to the vehicle speed signal V.

[0113] As an example, after obtaining the second friction compensation torque, the on-board controller may compare the second friction compensation torque with the upper limit and the lower limit of the vehicle speed friction compensation torque, so as to obtain the basic friction compensation torque according to the comparison result.

[0114] As an example, in step S501, when the second friction compensation torque is greater than or equal to the lower limit of the vehicle speed friction compensation torque and the second friction compensation torque is less than or equal to the upper limit of the vehicle speed friction compensation torque, the vehicle-mounted controller can determine that the second friction compensation torque does not exceed its vehicle speed friction limit, and can determine the second friction compensation torque as the basic friction compensation torque, so that the final output basic friction compensation torque is within the safe and controllable vehicle speed friction limit, which helps to ensure the safety of vehicle driving and handling stability.

[0115] As an example, in step S502, the vehicle controller can determine that the second friction compensation torque exceeds its vehicle speed friction limit when the second friction compensation torque is less than the lower limit of the vehicle speed friction compensation torque, or the second friction compensation torque is greater than the upper limit of the vehicle speed friction compensation torque, and can determine the vehicle speed friction limit as the second friction compensation torque, that is, determine the lower limit of the vehicle speed friction compensation torque or the upper limit of the vehicle speed friction compensation torque as the basic friction compensation torque, so that the final output basic friction compensation torque is within the safe and controllable vehicle speed friction limit, which helps to ensure the safety of vehicle driving and handling stability.

[0116] In this embodiment, according to whether the second friction compensation torque is within the safety range defined by the lower limit of the vehicle speed friction compensation torque and the upper limit of the vehicle speed friction compensation torque, any one of the second friction compensation torque, the lower limit of the vehicle speed friction compensation torque and the upper limit of the vehicle speed friction compensation torque is determined as the basic friction compensation torque to ensure that the final output basic friction compensation torque is within the safe and controllable vehicle speed friction limit, which helps to ensure the safety of vehicle driving and the handling stability.

[0117] In one embodiment, if Figure 6 As shown, step S202, i.e. determining the adaptive friction compensation torque according to the steering wheel torque signal and the basic friction compensation torque, includes:

[0118] S601: performing trend calculation on the steering wheel torque signal and the calibration torque signal to determine a target change trend value;

[0119] S602: Determine a target gain coefficient according to the target change trend value;

[0120] S603: Determine an adaptive friction compensation torque according to the target gain coefficient and the basic friction compensation torque.

[0121] The calibrated torque signal refers to the torque signal of the steering wheel in the active return condition which is calibrated in advance. The calibrated torque signal can be understood as the torque signal of the steering wheel in the active return condition which is determined by the calibration test when the vehicle leaves the factory. The target change trend value refers to the trend value calculated according to the steering wheel torque signal for finally determining the target gain coefficient.

[0122] As an example, in step S601, when the vehicle is in the active return-to-center condition, the on-board controller may perform difference processing on the steering wheel torque signal T acquired in real time and the pre-set calibration torque signal, so as to determine the target change trend value according to the torque difference calculated between the two. Generally speaking, when the vehicle is in the active return-to-center condition, the steering wheel torque signal acquired should remain unchanged or change slightly, and its value can more intuitively reflect the magnitude of the friction force. Therefore, the steering wheel torque signal T acquired in real time and the pre-set calibration torque signal can be trend-changed, so that the acquired target change trend value can more intuitively reflect the change of the friction force due to structural aging.

[0123] The target gain coefficient refers to a coefficient determined according to the target change trend value and used to perform gain adjustment on the basic friction compensation torque.

[0124] As an example, in step S602, after obtaining the target change trend value, the on-board controller can perform a table lookup operation based on the target change trend value, specifically querying a preset trend gain mapping table based on the target change trend value, and can quickly determine the target gain coefficient that can be used for gain compensation. The trend gain mapping table refers to a mapping table that is preset to reflect the mapping relationship between the change trend and the gain coefficient.

[0125] As an example, in step S603, after determining the target gain coefficient, the onboard controller may use the target gain coefficient to perform gain adjustment on the basic friction compensation torque to determine the adaptive friction compensation torque. In this example, the onboard controller may determine the product of the target gain coefficient and the basic friction compensation torque as the adaptive friction compensation torque.

[0126] In this embodiment, the vehicle-mounted controller determines the target change trend value reflecting the friction force due to structural aging based on the steering wheel torque signal T and the calibrated torque signal, and then determines the corresponding target gain coefficient based on the target change trend value, so that the target gain coefficient matches its structural aging condition, and then uses the target gain coefficient to perform gain adjustment on the basic friction compensation torque to obtain the gained adaptive friction compensation torque, so that the adaptive friction compensation torque is related to the aging degree of the steering mechanism, which helps to ensure that the friction compensation assist determined based on it can ensure smooth and comfortable steering of the steering system.

[0127] In one embodiment, if Figure 7 As shown, step S601, i.e., performing trend calculation on the steering wheel torque signal and the calibration torque signal to determine the target change trend value, includes:

[0128] S701: Determine a current change trend value corresponding to the steering wheel torque signal according to the steering wheel torque signal and the calibration torque signal;

[0129] S702: Determine the current change trend value as the target change trend value.

[0130] As an example, in step S701, when the vehicle is in an active return-to-center condition, the on-board controller may perform difference processing on the steering wheel torque signal T acquired in real time and the pre-set calibration torque signal, and determine the torque difference between the steering wheel torque signal T and the calibration torque signal as the current change trend value corresponding to the steering wheel torque signal acquired at the current moment. In this example, when the vehicle is in an active return-to-center condition, the on-board controller may perform difference processing on the steering wheel torque signal T corresponding to the return-to-center start moment or the return-to-center end moment and the pre-set calibration torque signal, and determine the difference between the two as the current change trend value.

[0131] As an example, in step S702, the on-board controller can directly determine the current change trend value as the target change trend value when obtaining the current change trend value corresponding to each steering wheel torque signal, thereby ensuring the efficiency of determining the target change trend value and helping to improve the overall efficiency. Since the current change trend value corresponding to the steering wheel torque signal collected at each current moment reflects the change in friction due to structural aging at the current moment, and the duration of this active return condition is short, the change in friction due to structural changes during this period is not much different, therefore, the current change trend value can be directly determined as the target change trend value to simplify the calculation steps and help improve processing efficiency.

[0132] In this embodiment, when the vehicle is in an active return-to-center condition, the current change trend value calculated from the steering wheel torque signal and the calibrated torque signal collected at the current moment is directly determined as the target change trend value to simplify the calculation steps and help improve processing efficiency.

[0133] In one embodiment, if Figure 8 As shown, step S601, i.e., performing trend calculation on the steering wheel torque signal and the calibration torque signal to determine the target change trend value, includes:

[0134] S801: Determine a current change trend value corresponding to the steering wheel torque signal according to the steering wheel torque signal and the calibration torque signal;

[0135] S802: Determine an average change trend value according to all current change trend values ​​corresponding to the active return to normal working condition;

[0136] S803: Determine a current change trend error according to the current change trend value and the average change trend value;

[0137] S803: If the current change trend error is less than the change trend error threshold, the current change trend value is determined as the target change trend value;

[0138] S805: If the current change trend error is not less than the change trend error threshold, the average change trend value is determined as the target change trend value.

[0139] The change trend error threshold is a preset threshold used to evaluate whether the change trend error is abnormal.

[0140] As an example, in step S801, when the vehicle is in an active self-centering condition, the on-board controller may perform difference processing on the steering wheel torque signal T acquired in real time and a preset calibration torque signal, and determine the torque difference between the steering wheel torque signal T and the calibration torque signal as the current change trend value corresponding to the steering wheel torque signal collected at the current moment.

[0141] As an example, in step S802, after obtaining all current change trend values ​​under this active return to centering condition, that is, obtaining all current change trend values ​​between the start time and the end time of this active return to centering, the on-board controller calculates the average of all current change trend values ​​to determine the average change trend value.

[0142] As an example, in step S803, the vehicle controller may perform difference processing on the current change trend value and the average change trend value, and determine the difference between the two as the current change trend error, so as to evaluate whether the calculated current change trend value has an abnormality based on the current change trend error, and then evaluate whether the corresponding steering wheel torque signal T has an error.

[0143] As an example, in step S804, the on-board controller may compare the current change trend error with a pre-set change trend error threshold. If the current change trend error is less than the change trend error threshold, it can be determined that there is no abnormality in the current change trend value corresponding to the current change trend error, and the current change trend value can be determined as the target change trend value, which can ensure that subsequent adaptive friction torque compensation is performed based on the normal current change trend value, thereby helping to ensure the driving safety and handling stability of the vehicle.

[0144] As an example, in step S805, the on-board controller may compare the current change trend error with a pre-set change trend error threshold. If the current change trend error is not less than the change trend error threshold, it can be determined that the current change trend value corresponding to the current change trend error is abnormal, and the average change trend value can be determined as the target change trend value. This can avoid subsequent adaptive friction torque compensation based on the abnormal current change trend value, which helps to ensure the driving safety and handling stability of the vehicle.

[0145] In this embodiment, when the vehicle is in an active self-centering condition, the current change trend value is first calculated based on the steering wheel torque signal and the calibrated torque signal collected at the current moment, and then the average change trend value is determined based on all the current change trend values ​​collected under the entire active self-centering condition; based on the current change trend value and the average change trend value, the current change trend error is determined, and based on the comparison result of the current change trend error with the change trend error threshold, the current change trend value or the average change trend value is determined as the target change trend value, so as to achieve the purpose of taking into account efficiency and ensuring the driving safety and handling stability of the vehicle.

[0146] In one embodiment, if Fig. 9 As shown, step S602, i.e. determining the target gain coefficient according to the target change trend value, includes:

[0147] S901: querying a trend gain mapping table according to the target change trend value to determine an original gain coefficient corresponding to the target change trend value;

[0148] S902: Limit the amplitude of the original gain coefficient to determine the target gain coefficient.

[0149] As an example, in step S901, after obtaining the target change trend value, the on-board controller can perform a table lookup operation based on the target change trend value, specifically querying a preset trend gain mapping table based on the target change trend value, and the gain coefficient corresponding to the target change trend value in the trend gain mapping table can be determined as the original gain coefficient, which can ensure the efficiency of obtaining the original gain coefficient. In this example, the original gain coefficient refers to the gain coefficient directly determined by querying the trend gain mapping table according to the target change trend value.

[0150] As an example, in step S902, after obtaining the original gain coefficient corresponding to the target change trend value, the on-board controller needs to limit the amplitude of the original gain coefficient to obtain the target gain coefficient within the safety range of the gain coefficient.

[0151] In this embodiment, the original gain coefficient obtained by looking up the table based on the target change trend value is a coefficient greater than or equal to 1. If the coefficient is too large, the adaptive friction compensation torque determined by using the coefficient to perform gain adjustment on the basic friction compensation torque will be too large, thereby affecting the driver's handling feel and interfering with the driver's normal driving. Therefore, it is necessary to limit the amplitude of the original gain coefficient to achieve the purpose of limiting the adaptive friction compensation torque determined subsequently, which helps to ensure driving safety and handling stability based on the adaptive friction compensation torque for friction torque compensation.

[0152] In one embodiment, if Fig.10 As shown, step S902, i.e., limiting the amplitude of the original gain coefficient to determine the target gain coefficient, includes:

[0153] S1001: If the original gain coefficient is less than the preset gain coefficient limit, the original gain coefficient is determined as the target gain coefficient;

[0154] S1002: If the original gain coefficient is not less than the preset gain coefficient limit, determine the target gain coefficient according to the gain coefficient limit.

[0155] The gain coefficient limit is a preset threshold used to limit the amplitude of the gain coefficient.

[0156] As an example, in step S1001, after obtaining the original gain coefficient corresponding to the target change trend value, the on-board controller can compare the original gain coefficient with the pre-set gain coefficient limit. If the original gain coefficient is smaller than the pre-set gain coefficient limit, it means that the original gain coefficient is within a safe range. The original gain coefficient can be determined as the target gain coefficient to ensure that the adaptive friction compensation torque determined by gain adjustment of the basic friction compensation torque using the target gain coefficient is also within a safe range, which helps to ensure driving safety and handling stability based on the adaptive friction compensation torque for friction torque compensation.

[0157] As an example, in step S1002, after obtaining the original gain coefficient corresponding to the target change trend value, the on-board controller can compare the original gain coefficient with the pre-set gain coefficient limit. If the original gain coefficient is not less than the pre-set gain coefficient limit, it means that the original gain coefficient is not within the safety range. If the gain adjustment is directly based on the original gain coefficient, the adaptive friction compensation torque after the gain adjustment will exceed the safety range. Therefore, the gain coefficient limit can be determined as the target gain coefficient to ensure that the adaptive friction compensation torque determined by gain adjustment of the basic friction compensation torque using the target gain coefficient is also within the safety range, which helps to ensure driving safety and handling stability based on the adaptive friction compensation torque for friction torque compensation.

[0158] In one embodiment, if Fig.11 As shown, step S114, i.e. determining the target friction compensation torque according to the basic friction compensation torque and the adaptive friction compensation torque, includes:

[0159] S1101: determining a target compensation torque error according to a basic friction compensation torque and an adaptive friction compensation torque;

[0160] S1102: If the target compensation torque error is not within the compensation torque error threshold, the steering mechanism is controlled to operate according to the adaptive friction compensation torque.

[0161] The target compensation torque error is an error value determined by performing error calculation based on the basic friction compensation torque and the adaptive friction compensation torque.

[0162] As an example, in step S1101, when the vehicle is in the active self-aligning condition, the on-board controller may perform difference processing based on the adaptive friction compensation torque and the basic friction compensation torque at each current moment to determine the measured compensation torque error corresponding to each current moment; the measured compensation torque error corresponding to each current moment may be determined as the target compensation torque error; or the mean of all measured compensation torque errors at the current moment between the start moment and the end moment of this active self-alignment may be calculated, and the mean of all measured compensation torque errors determined by this active self-alignment may be determined as the target compensation torque error; or weighted calculation or other calculation may be performed on all measured compensation torque errors at the current moment between the start moment and the end moment of this active self-alignment, and the calculation result may be determined as the target compensation torque error.

[0163] The compensation torque error threshold is a preset threshold used to evaluate whether the compensation torque error reaches a serious aging standard.

[0164] As an example, in step S1102, after obtaining the target compensation torque error under the active return working condition, the on-board controller may compare the target compensation torque error with the preset compensation torque error threshold. If the target compensation torque error is within the compensation torque error threshold, it is determined that the friction force of the steering mechanism does not change much, and the aging of the steering mechanism does not reach the severe aging standard. At this time, the steering mechanism is controlled to work according to the basic friction compensation torque, that is, the basic friction compensation torque is determined as the target friction compensation torque, and the steering mechanism is controlled to work according to the target friction compensation torque, without the need to switch the friction compensation torque, which helps to ensure the steering stability of the steering system. On the contrary, if the target compensation torque error is not within the compensation torque error threshold, it is determined that the friction force of the steering mechanism changes greatly, and the aging of the steering mechanism reaches the severe aging standard. At this time, the steering mechanism is controlled to work according to the adaptive friction compensation torque, that is, the adaptive friction compensation torque is determined as the target friction compensation torque, and the steering mechanism is controlled to work according to the target friction compensation torque, so that the friction compensation torque of the steering mechanism is related to the aging degree of the steering mechanism, which helps to ensure the steering smoothness and comfort of the steering mechanism, and thus ensure the driving control stability and safety.

[0165] In this embodiment, a target compensation torque error is determined based on the basic friction compensation torque and the adaptive friction compensation torque. The target compensation torque error can effectively reflect the aging degree of the steering mechanism. When the target compensation torque error is not within the compensation torque error threshold, it can be determined that the friction force of the steering mechanism has changed significantly, and the aging of the steering mechanism has reached the severe aging standard. At this time, the steering mechanism is controlled according to the adaptive friction compensation torque, so that the friction compensation torque of the steering mechanism is related to the aging degree of the steering mechanism, which helps to ensure smooth and comfortable steering of the steering mechanism, and thus ensure driving control stability and safety.

[0166] In one embodiment, if Fig.12 As shown, step S1102, that is, if the target compensation torque error is not within the compensation torque error threshold, the steering mechanism is controlled to work according to the adaptive friction compensation torque, including:

[0167] S1201: If the target compensation torque error is not within the compensation torque error threshold, obtaining the current vehicle operating condition;

[0168] S1202: If the current vehicle operating condition is a safe condition, the steering mechanism is controlled to operate according to the adaptive friction compensation torque.

[0169] As an example, in step S1201, when the target compensation torque error is not within the compensation torque error threshold, the on-board controller can determine that the friction force of the steering mechanism has changed greatly and its aging has reached the severe aging standard. At this time, the current vehicle data can be obtained through the bus, and the current vehicle data refers to the vehicle data collected at the current moment. Then, the pre-set vehicle operating condition judgment logic is called to judge and process the current vehicle data collected in real time to determine the corresponding current vehicle operating condition, which can be any of a safe operating condition and an unsafe operating condition. The safe operating condition here refers to the operating condition in which switching the friction compensation torque will not affect its driving safety. Conversely, the unsafe operating condition refers to the operating condition in which switching the friction compensation torque will affect its driving safety.

[0170] In one embodiment, the current vehicle operating condition is determined based on a steering wheel angle signal and a steering wheel torque signal; the safe operating condition is a condition in which the absolute value of the steering wheel angle signal is less than a preset angle threshold, and the absolute value of the steering wheel torque signal is less than a preset torque threshold.

[0171] The preset angle threshold is a preset threshold used to evaluate whether the angle is in a safe working condition, and the preset angle threshold can be set to 0 or a value close to 0. The preset torque threshold is a preset threshold used to evaluate whether the torque is in a safe working condition, and the preset torque threshold can be set to 0 or a threshold close to 0.

[0172] As an example, when the on-board controller needs to evaluate the current vehicle operating condition, it can obtain the current vehicle data such as the steering wheel angle signal A and the steering wheel torque signal T sent by the torque angle sensor mounted on the vehicle, and then compare the absolute value of the steering wheel angle signal A with the preset angle threshold, and compare the steering wheel torque signal T with the preset torque threshold, so as to determine the current vehicle operating condition according to the comparison result. When the absolute value of the steering wheel angle signal A is less than the preset angle threshold, and the absolute value of the steering wheel torque signal T is less than the preset torque threshold, the on-board controller can determine that the steering wheel has returned to the middle position or close to the middle position, the vehicle is not turning, and the external force / torque acting on the steering wheel is small or close to zero, and there is no external force acting on the steering wheel. At this time, if the friction compensation torque is switched, the driver will not feel the torque suddenly disappear or increase, so it will not affect the driving stability and safety, and the current vehicle operating condition can be determined to be a safe condition. On the contrary, when the absolute value of the steering wheel angle signal A is not less than the preset angle threshold, or the absolute value of the steering wheel torque signal T is not less than the preset torque threshold, the vehicle controller can determine that the steering wheel has not returned to the middle position or close to the middle position, and can determine that the vehicle is still in the steering process, or the external force / torque acting on the steering wheel is large. At this time, if the friction compensation torque is switched, the driver will feel the torque suddenly disappear or increase, which will affect the driving control stability and safety, and it can be determined that the current vehicle operating condition is an unsafe condition.

[0173] In this embodiment, based on the steering wheel angle signal A and the steering wheel torque signal T sent by the torque angle sensor loaded on the vehicle, it is possible to evaluate whether the vehicle is turning and determine whether a large external force is acting on the steering wheel, thereby determining whether the current vehicle operating condition is a safe condition or an unsafe condition, and then determining whether it is possible to switch to an adaptive friction compensation torque.

[0174] As an example, in step S1202, when the current vehicle operating condition is a safe condition, the on-board controller indicates that switching the vehicle from the original basic friction compensation torque to the adaptive friction compensation torque will not affect the driver's safe driving. At this time, the steering mechanism can be controlled according to the adaptive friction compensation force, that is, the adaptive friction compensation torque is determined as the target friction compensation torque, so as to control the steering mechanism based on the target friction compensation torque. That is, only when the vehicle is in a safe condition will it switch to using the adaptive friction compensation torque for friction torque compensation, which helps to ensure the handling stability of the steering system.

[0175] In this example, when the current vehicle operating condition is an unsafe condition, the on-board controller indicates that the vehicle's switching from the original basic friction compensation torque to the adaptive friction compensation torque will affect the driver's safe driving. At this time, the basic friction compensation torque is still determined as the target friction compensation torque so that the steering mechanism can be controlled based on the basic friction compensation torque. It will not be switched to controlling the steering mechanism based on the adaptive friction compensation torque until the vehicle enters a safe condition. That is, when the vehicle transitions from an unsafe condition to a safe condition, the basic friction compensation torque is still used for friction torque compensation to avoid the steering process affecting the driving control stability.

[0176] Generally speaking, after discovering the mechanical aging of the steering mechanism and calculating its adaptive friction compensation torque, if during the steering process, the basic friction compensation torque is directly switched to the adaptive friction compensation torque, the torque felt by the driver will suddenly disappear or increase, affecting driving safety. Therefore, it is necessary to switch to determining the adaptive friction compensation torque as the target friction compensation torque and controlling the steering mechanism only when the vehicle is in a safe condition; when the vehicle is in an unsafe condition, maintain the basic friction compensation torque as the target friction compensation torque and control the steering mechanism to ensure driving stability and safety.

[0177] It should be understood that the order of execution of the steps in the above embodiment does not necessarily mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0178] In one embodiment, a vehicle-mounted controller is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the electric power steering compensation method in the above embodiment is implemented, for example Figure 1 S111-S115 as shown, or Figures 2 to 11 To avoid repetition, it will not be described here.

[0179] In one embodiment, a steering system is provided, including the vehicle-mounted controller in the above embodiment and a steering mechanism connected to the vehicle-mounted controller, wherein the vehicle-mounted controller can control the steering mechanism to work according to the electric power steering compensation method in the above embodiment, for example Figure 1 S101-S103 as shown, or Figures 2 to 12 To avoid repetition, it will not be described here.

[0180] In one embodiment, a vehicle is provided, comprising the steering system in the above embodiment.

[0181] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the electric power steering compensation method in the above embodiment is implemented, for example Figure 1 S101-S103 as shown, or Figures 2 to 12 To avoid repetition, it will not be described here.

[0182] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0183] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0184] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. An electric power steering compensation method, characterized in that: include: Obtain basic friction compensation torque; determining an adaptive friction compensation torque according to the steering wheel torque signal and the basic friction compensation torque; When the basic friction compensation torque and the adaptive friction compensation torque meet preset conditions, the steering mechanism is controlled to operate according to the adaptive friction compensation torque.

2. The electric power steering compensation method according to claim 1, characterized in that: The obtaining of the basic friction compensation torque comprises: Obtaining a steering wheel speed signal, a steering wheel torque signal and a vehicle speed signal; A basic friction compensation torque is obtained according to the steering wheel speed signal and the vehicle speed signal.

3. The electric power steering compensation method according to claim 2, characterized in that: The obtaining of the basic friction compensation torque according to the steering wheel speed signal and the vehicle speed signal comprises: determining a first friction compensation torque and a friction force direction according to the steering wheel speed signal; Determining a vehicle speed friction gain and a vehicle speed friction limit according to the vehicle speed signal; A basic friction compensation torque is acquired according to the first friction compensation torque, the friction force direction, the vehicle speed friction gain and the vehicle speed friction limit.

4. The electric power steering compensation method according to claim 3, characterized in that: The obtaining of the basic friction compensation torque according to the first friction compensation torque, the friction force direction, the vehicle speed friction gain and the vehicle speed friction limit comprises: determining a second friction compensation torque according to the first friction compensation torque, the friction force direction and the vehicle speed friction gain; The vehicle speed friction limiter is used to limit the amplitude of the second friction compensation torque to obtain a basic friction compensation torque.

5. The electric power steering compensation method according to claim 4, characterized in that: The step of using the vehicle speed friction limit to limit the amplitude of the second friction compensation torque to obtain a basic friction compensation torque includes: If the second friction compensation torque is within the vehicle speed friction limit, determining the second friction compensation torque as the basic friction compensation torque; If the second friction compensation torque is not within the vehicle speed friction limit, the basic friction compensation torque is determined based on the vehicle speed friction limit.

6. The electric power steering compensation method according to claim 1, characterized in that: The step of determining the adaptive friction compensation torque according to the steering wheel torque signal and the basic friction compensation torque comprises: Performing trend calculation on the steering wheel torque signal and the calibration torque signal to determine a target change trend value; Determining a target gain coefficient according to the target change trend value; An adaptive friction compensation torque is determined according to the target gain coefficient and the basic friction compensation torque.

7. The electric power steering compensation method according to claim 6, characterized in that: The performing trend calculation on the steering wheel torque signal and the calibration torque signal to determine the target change trend value includes: When the vehicle is in an active return-to-center condition, determining a current change trend value corresponding to the steering wheel torque signal according to the steering wheel torque signal and the calibrated torque signal; The current change trend value is determined as the target change trend value.

8. The electric power steering compensation method according to claim 6, characterized in that: The performing trend calculation on the steering wheel torque signal and the calibration torque signal to determine the target change trend value includes: Determining a current change trend value corresponding to the steering wheel torque signal according to the steering wheel torque signal and the calibrated torque signal; Determine an average change trend value according to all the current change trend values ​​corresponding to this active return to normal working condition; Determining a current change trend error according to the current change trend value and the average change trend value; If the current change trend error is less than the change trend error threshold, determining the current change trend value as the target change trend value; If the current change trend error is not less than the change trend error threshold, the average change trend value is determined as the target change trend value.

9. The electric power steering compensation method according to claim 6, characterized in that: Determining a target gain coefficient according to the target change trend value includes: According to the target change trend value, a trend gain mapping table is searched to determine an original gain coefficient corresponding to the target change trend value; The original gain coefficient is amplitude-limited to determine a target gain coefficient.

10. The electric power steering compensation method according to claim 9, characterized in that: The step of limiting the amplitude of the original gain coefficient to determine the target gain coefficient includes: If the original gain coefficient is less than the preset gain coefficient limit, the original gain coefficient is determined as the target gain coefficient; If the original gain coefficient is not less than the preset gain coefficient limit, the target gain coefficient is determined according to the gain coefficient limit.

11. The electric power steering compensation method according to claim 1, characterized in that: When the basic friction compensation torque and the adaptive friction compensation torque meet the preset conditions, the steering mechanism is controlled to work according to the adaptive friction compensation torque, including: Determining a target compensation torque error according to the basic friction compensation torque and the adaptive friction compensation torque; If the target compensation torque error is not within the compensation torque error threshold, the steering mechanism is controlled to operate according to the adaptive friction compensation torque.

12. The electric power steering compensation method according to claim 11, characterized in that: If the target compensation torque error is not within the compensation torque error threshold, controlling the steering mechanism to work according to the adaptive friction compensation torque includes: If the target compensation torque error is not within the compensation torque error threshold, obtaining the current vehicle operating condition; If the current vehicle operating condition is a safe operating condition, the steering mechanism is controlled to operate according to the adaptive friction compensation torque.

13. The electric power steering compensation method according to claim 12, characterized in that: The current vehicle operating condition is determined according to the steering wheel angle signal and the steering wheel torque signal; The safe operating condition is a condition in which the absolute value of the steering wheel angle signal is less than a preset angle threshold, and the absolute value of the steering wheel torque signal is less than a preset torque threshold.

14. A vehicle-mounted controller, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the electric power steering compensation method according to any one of claims 1 to 13 is implemented.

15. A steering system, characterized in that: It comprises the on-vehicle controller as claimed in claim 14 and a steering mechanism connected to the on-vehicle controller.

16. A vehicle, characterized in that: Includes the steering system as claimed in claim 15.

17. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the electric power steering compensation method according to any one of claims 1 to 13 is implemented.

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