Electric power steering system and control method and medium thereof, electronic equipment, and vehicle

Abstract

The present invention discloses an electric power steering system and a control method thereof, as well as a medium, an electronic device, and a vehicle. The control method of the electric power steering system includes: obtaining the vehicle speed and the torque of the steering wheel; judging whether the vehicle speed and the torque meet the preset conditions; if so, performing damping control on the power motor in the electric power steering system according to the vehicle speed. The control method of the electric power steering system can realize the judgment of whether to perform damping control by the vehicle speed and the torque, with stricter judgment conditions and clearer scenarios, thereby improving driving safety and reducing disturbances caused by misjudgment.

Description

Technical Field

[0001] The present invention relates to the field of vehicle technology, and in particular to an electric power steering system and a control method and medium thereof, electronic equipment, and a vehicle. Background Art

[0002] The electric power steering system is a power steering system that relies on an electric motor to provide auxiliary torque. It has the advantages of variable power characteristics, energy saving, and simple structure. It is gradually replacing the traditional hydraulic power steering system.

[0003] However, the existing electric power steering system has the following problems: it relies on vehicle speed as the only condition to trigger damping control. When the vehicle speed reaches a certain threshold value, the damping control will be triggered, so that when driving at high speed, the electric power steering system will always be in damping control mode; moreover, the existing electric power steering system relies on directly providing reverse current to perform damping control. Once the electronic control center makes an incorrect judgment, it will cause the vehicle to move unpredictably. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, the first object of the present invention is to provide a control method of an electric power steering system to improve driving safety.

[0005] A second object of the present invention is to provide a computer-readable storage medium.

[0006] A third objective of the present invention is to provide an electronic device.

[0007] A fourth objective of the present invention is to provide an electric power steering system.

[0008] A fifth object of the present invention is to provide a vehicle.

[0009] To achieve the above-mentioned objectives, an embodiment of the first aspect of the present invention proposes a control method for an electric power steering system, comprising: obtaining the vehicle speed and the steering wheel torque; determining whether the vehicle speed and the torque meet preset conditions; if so, performing damping control on the power motor in the electric power steering system according to the vehicle speed.

[0010] To achieve the above-mentioned purpose, a second aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the above-mentioned control method of the electric power steering system is implemented.

[0011] To achieve the above-mentioned purpose, the third aspect of the present invention proposes an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the above-mentioned control method of the electric power steering system is implemented.

[0012] To achieve the above-mentioned objectives, the fourth aspect of the present invention proposes an electric power steering system, comprising: a torque sensor for collecting the torque of a vehicle steering wheel; a vehicle speed sensor for collecting the vehicle speed; a power-assist motor, the power-assist motor being connected to the steering wheel and being used to provide assistance or resistance to the steering wheel; and an electronic control unit, the electronic control unit being respectively connected to the torque sensor, the vehicle speed sensor and the power-assist motor and being used to determine whether the vehicle speed and the torque meet preset conditions, and when the preset conditions are met, performing damping control on the power-assist motor in the electric power steering system according to the vehicle speed.

[0013] To achieve the above objectives, a fifth aspect of the present invention provides a vehicle comprising the above electric power steering system.

[0014] The electric power steering system and control method thereof, as well as the medium, electronic device, and vehicle of the embodiments of the present invention can obtain the vehicle speed and steering wheel torque, and then determine whether to perform damping control based on the vehicle speed and steering wheel torque, thereby achieving joint judgment through vehicle speed and torque, with stricter judgment conditions and clearer scenarios, thereby improving driving safety and reducing disturbances caused by misjudgment.

[0015] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a flow chart of a control method of an electric power steering system according to an embodiment of the present invention;

[0017] Figure 2 is a schematic diagram of an H-bridge circuit of an example of the present invention;

[0018] Figure 3 is a flow chart of a control method of an electric power steering system according to another embodiment of the present invention;

[0019] Figure 4 is a schematic diagram of the relationship between vehicle speed and duty cycle according to an example of the present invention;

[0020] Figure 5 is a schematic diagram of a control method of an electric power steering system according to an example of the present invention;

[0021] Figure 6 is a flow chart of a control method of an electric power steering system according to an example of the present invention;

[0022] Figure 7 is a structural block diagram of an electric power steering system according to an embodiment of the present invention;

[0023] Figure 8 4 is a structural block diagram of a vehicle according to an embodiment of the present invention. DETAILED DESCRIPTION

[0024] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0025] When driving a vehicle, the driver often needs to control the steering wheel of the vehicle. When the vehicle is traveling at a low speed, the rotational resistance torque between the tire and the ground is large, and when the vehicle is traveling at a high speed, the rotational resistance torque between the tire and the ground is small. Therefore, the electric power steering system needs to provide a certain amount of power to help the driver complete the steering when the vehicle speed is low and steering is more difficult. When the vehicle speed is high, in order to prevent the steering wheel from turning due to unexpected disturbances and thus causing danger, and also to provide a certain steering feel, the electric power steering system needs to provide a certain damping torque. However, when the vehicle is traveling at high speed, there may be a scene where the driver needs to avoid obstacles in front. At this time, if the electric power steering system is still providing a damping torque to prevent the steering wheel from turning, it may cause a safety accident. Moreover, once the electric power steering system makes an error in judgment, the motor will output an inappropriate reverse current to bring a reverse rotation torque that does not match the current situation, resulting in unpredictable movement and a safety hazard.

[0026] In order to solve the problems existing in the existing electric power steering system, the present invention proposes an electric power steering system and a control method and medium, electronic equipment and vehicle.

[0027] The electric power steering system and control method thereof, medium, electronic device, and vehicle according to embodiments of the present invention will be described below with reference to the accompanying drawings.

[0028] Figure 1 The figure is a flow chart of a control method of an electric power steering system according to an embodiment of the present invention.

[0029] like Figure 1 As shown, the control method of the electric power steering system includes:

[0030] S11, obtaining the vehicle speed and steering wheel torque.

[0031] Specifically, a method for obtaining the vehicle speed and steering wheel torque can be preset. For example, the vehicle's wheel speed can be obtained by a wheel speed sensor arranged at the wheel, and then the vehicle speed can be calculated by the vehicle's wheel speed. The steering wheel rotation speed can be obtained by a sensor arranged at the steering wheel drive shaft.

[0032] S12, determining whether the vehicle speed and torque meet preset conditions.

[0033] The above-mentioned preset conditions include: the vehicle speed is greater than a first preset speed threshold, the torque is less than a preset torque threshold, and is maintained for a preset time.

[0034] Specifically, by comparing the vehicle speed with the first preset speed threshold, if the vehicle speed is greater than the first preset speed threshold, it can be considered that the current vehicle is in a high-speed driving state. The value range of the first preset speed threshold is 70-90km / h, for example, it can be 80km / h, that is, if the vehicle speed is greater than 80km / h, it is considered that the vehicle is in a high-speed driving state. By comparing the torque of the steering wheel with the preset torque threshold, if the torque of the steering wheel is less than the preset torque threshold, it can be considered that the current driver has not performed an emergency operation such as slamming the steering wheel, that is, it is considered that the current vehicle is not in a scene where some drivers need to perform emergency operations such as avoiding obstacles ahead. Furthermore, if the duration of the vehicle speed being greater than or less than the preset speed threshold and the torque being less than the preset torque threshold is greater than the preset time, it can be considered that the above judgment of the vehicle speed being greater than or less than the preset speed threshold and the torque being less than the preset torque threshold is not caused by data acquisition errors such as disturbance errors when collecting data. The value range of the preset time is 50-200ms, for example, it can be 100ms.

[0035] It should be noted that the above-mentioned preset torque threshold should be less than the torque at the inflection point of the dead zone, and a certain hysteresis interval should be made to prevent the motor from shaking due to a sudden change in current, thereby improving the driver's driving experience. Specifically, in the process of the steering wheel torque increasing from zero, the steering wheel torque will first be in the damping control interval, then the hysteresis interval, then the dead zone inflection point, and then the power-assist interval. In the hysteresis interval, the motor performs neither damping control nor power-assist control, that is, the hysteresis interval is a transition interval between the damping control interval and the power-assist interval, thereby preventing the motor from shaking due to switching between damping control and power-assist control. The above-mentioned dead zone refers to the interval where the motor does not provide power assistance, that is, the motor starts to provide power assistance after the steering wheel torque reaches the dead zone inflection point, and damping control is set within the dead zone.

[0036] S13: If the conditions are met, damping control is performed on the power steering motor in the electric power steering system according to the vehicle speed.

[0037] Specifically, if the above-mentioned preset conditions are met, the vehicle enters the damping control mode, obtains the current speed of the vehicle, and adjusts the control current according to the vehicle speed to adjust the damping torque provided by the power-assisted motor, thereby providing different damping torques according to the different resistance torques between the tires and the ground caused by different vehicle speeds. That is, the higher the vehicle speed, the smaller the resistance torque between the tires and the ground, and the greater the damping torque provided by the power-assisted motor.

[0038] The power-assisting motor may be driven, for example, by an H-bridge having four bridge arms, or by a circuit having six bridge arms or eight bridge arms, or by other possible circuits.

[0039] In this way, the vehicle speed and steering wheel torque can be obtained first, and then whether to perform damping control can be determined based on the vehicle speed and steering wheel torque. The judgment conditions are more stringent and the scenarios are clearer, thereby improving driving safety and reducing disturbances caused by misjudgment.

[0040] In one embodiment of the present invention, the booster motor adopts an H-bridge driving mode. The H-bridge circuit is as follows Figure 2 As shown, it includes two upper bridge arms and two lower bridge arms. Among them, two MOS tubes are arranged on the two upper bridge arms: FET (a) and FET (b), and two MOS tubes are arranged on the two lower bridge arms: FET (c) and FET (d), and then the power assist motor can be switched between the power assist control mode of providing power assist and the damping control mode of providing damping torque by controlling the on and off of the above four MOS tubes. Of course, the H-bridge may not use MOS tubes, for example, triodes, electromagnetic switches, etc. may be used.

[0041] At this time, see Figure 3 The damping control of the power-assisted motor in the electric power-assisted steering system according to the vehicle speed includes:

[0042] S31, determining a duty cycle according to the vehicle speed.

[0043] Specifically, a vehicle speed-duty cycle relationship model can be established in advance through experiments. In this model, when the vehicle speed is greater than a first preset speed threshold and less than a second preset speed threshold, the vehicle speed is positively correlated with the duty cycle; when the vehicle speed is greater than or equal to the second preset speed threshold, the duty cycle is always 100%. After obtaining the vehicle speed, the vehicle speed is substituted into the model to obtain the duty cycle of the PWM signal in the damping control mode. The model can be, for example, as follows Figure 4As shown, in this specific example, the first preset speed threshold is 80km / h, and the second preset speed threshold is 120km / h. After obtaining the vehicle speed, the vehicle speed can be substituted into the model to obtain the corresponding duty cycle, that is, when the vehicle speed is greater than 80km / h, the duty cycle of the output PWM signal starts to increase from 0, and when the vehicle speed reaches 120km / h, the duty cycle reaches the maximum, and thereafter as the vehicle speed increases, the duty cycle will remain unchanged.

[0044] S32, outputting a PWM signal to the lower arm of the H bridge according to the duty cycle, and controlling the upper arm of the H bridge to be turned off.

[0045] Specifically, see Figure 2 , by controlling the upper arm of the H-bridge to shut down and outputting a PWM signal to the lower arm of the H-bridge, the power-assisted motor enters the damping control mode. At this time, if the driver turns the steering wheel, the rotor in the power-assisted motor will rotate as the steering wheel turns. During the rotation, the rotor will generate an induced back electromotive force, which will generate a torque that hinders the rotation of the rotor. This torque is the damping torque that the power-assisted motor needs to provide in the damping control mode. Since the lower arm of the H-bridge is turned on by the PWM signal, by adjusting the duty cycle of the PWM signal, it is possible to provide different damping torques when the driver turns the steering wheel.

[0046] It should be noted that the power-assisting motor in the embodiment of the present invention may not be driven by an H-bridge, as long as the structure of the driving circuit is similar to that of the H-bridge circuit. For example, it may be a circuit including three upper bridge arms and three lower bridge arms. At this time, if damping control is required, it is only necessary to control all three upper bridge arms to be turned off, control one lower bridge arm to be turned off and output a PWM signal to the remaining two lower bridge arms. In this way, even if a lower bridge arm fails, the power-assisting motor can still use the remaining lower bridge arms to provide damping torque, thereby improving the reliability of the control method of the electric power steering system.

[0047] Therefore, after the power-assisted motor enters the damping control mode, it can provide different damping torques at different vehicle speeds using different duty ratios of PWM signals, so that the damping provided can be quantified, and the vehicle will not be driven to rotate the steering wheel due to unexpected disturbances when driving at high speeds, thereby causing danger. It can also provide the driver with a certain steering feel to prevent the steering from feeling "floating", thereby improving the driver's driving experience. Moreover, since the power-assisted motor generates the damping torque by the driver's action of turning the steering wheel, if the driver does not turn the steering wheel, the power-assisted motor will not generate the damping torque. Even if the electric power steering system makes an error in judgment, the power-assisted motor will not generate the damping torque, thereby improving the safety of the vehicle.

[0048] The control method of the electric power steering system according to the embodiment of the present invention is described in detail below with reference to a specific example.

[0049] In this specific example, if Figure 5 As shown, it includes a sensor, a motor, a reducer, a steering gear, a steering shaft, and an electronic control unit. Among them, the sensor is a TAS (Torque and Angle Sensor), which collects the angle and torque of the steering shaft. The electronic control unit is composed of an ECU (Electronic Control Unit), which is used to receive the information collected by the TAS and receive information such as vehicle speed, and then make judgments based on the received information to control the motor to perform relevant controls, thereby achieving steering. The motor is a power-assisted motor, which adopts an H-bridge drive method, and is used to provide power assistance in the power-assisted control mode and provide damping torque in the damping control mode.

[0050] Specifically, see Figure 6 , during the driving process of the vehicle, first determine whether the vehicle speed is greater than the first preset speed threshold, which is a high-speed threshold. If it is greater than the high-speed threshold, it can be considered that the vehicle is currently in a high-speed driving state. If the vehicle speed is greater than the high-speed threshold, it is further determined whether the torque of the steering wheel is less than the preset torque threshold. If the torque of the steering wheel is less than the torque threshold, the timing is further started. If within the preset time range, the vehicle speed is greater than the high-speed threshold and the torque of the steering wheel is less than the preset torque threshold, it is determined that damping control is required. Then the electronic control unit obtains the current vehicle speed and determines the duty cycle of the current output to the motor according to the vehicle speed, so as to provide different damping torques at different vehicle speeds. If the power-assisted motor adopts an H-bridge drive mode, in the damping control mode, the power-assisted motor will only provide the damping torque after the driver turns the steering wheel, so that even if the ECU makes an incorrect judgment, the driving safety of the vehicle will not be affected by the incorrect damping torque provided by the power-assisted motor.

[0051] In summary, the control method of the electric power steering system of the embodiment of the present invention can obtain the vehicle speed and the torque of the steering wheel, and then determine whether to perform damping control according to the vehicle speed and the torque of the steering wheel, so as to achieve a joint judgment through the vehicle speed and torque, with stricter judgment conditions and clearer scenes, thereby improving driving safety and reducing disturbances caused by misjudgment. Moreover, the power-assisted motor adopts an H-bridge drive mode, and when performing damping control, the upper bridge arm of the H-bridge is controlled to be turned off, and the lower bridge arm of the H-bridge is controlled to be turned on, so that the power-assisted motor generates a damping torque according to the rotation of the steering wheel in the damping control mode, thereby preventing unpredictable movements due to misjudgment of the electric power-assisted steering system through a passive damping triggering mode.

[0052] Furthermore, the present invention provides a computer-readable storage medium.

[0053] In an embodiment of the present invention, a computer program is stored on a computer-readable storage medium, and when the computer program is executed by a processor, the above-mentioned control method of the electric power steering system is implemented.

[0054] The computer-readable storage medium of the embodiment of the present invention can obtain the vehicle speed and steering wheel torque when the computer program thereon is executed by the processor, and then determine whether to perform damping control based on the vehicle speed and steering wheel torque, thereby achieving a joint judgment through vehicle speed and torque, with stricter judgment conditions and clearer scenarios, thereby improving driving safety and reducing disturbances caused by misjudgment. In addition, the power-assisted motor adopts an H-bridge drive mode, and when performing damping control, the upper bridge arm of the H-bridge is controlled to be turned off, and the lower bridge arm of the H-bridge is controlled to be turned on, so that the power-assisted motor generates a damping torque according to the rotation of the steering wheel in the damping control mode, thereby preventing unpredictable movements due to misjudgment of the electric power steering system through a passive damping triggering mode.

[0055] Furthermore, the present invention provides an electronic device.

[0056] In an embodiment of the present invention, the electronic device includes 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 above-mentioned control method of the electric power steering system is implemented.

[0057] The electronic device of the embodiment of the present invention can obtain the vehicle speed and steering wheel torque by implementing the control method of the electric power steering system, and then judge whether to perform damping control according to the vehicle speed and steering wheel torque, so as to achieve a joint judgment through vehicle speed and torque, with stricter judgment conditions and clearer scenes, thereby improving driving safety and reducing disturbances caused by misjudgment. In addition, the power-assisted motor adopts an H-bridge drive mode, and when performing damping control, the upper bridge arm of the H-bridge is controlled to be turned off, and the lower bridge arm of the H-bridge is controlled to be turned on, so that the power-assisted motor generates a damping torque according to the rotation of the steering wheel in the damping control mode, thereby preventing unpredictable movements due to misjudgment of the electric power steering system through a passive damping trigger mode.

[0058] Furthermore, the present invention provides an electric power steering system.

[0059] Figure 7 4 is a structural block diagram of an electric power steering system according to an embodiment of the present invention.

[0060] like Figure 7 As shown, the electric power steering system 100 includes a torque sensor 101 , a vehicle speed sensor 102 , a power motor 103 , and an electronic control unit 104 .

[0061] Specifically, the torque sensor 101 is used to collect the torque of the vehicle steering wheel; the vehicle speed sensor 102 is used to collect the vehicle speed; the power-assist motor 103 is connected to the steering wheel and is used to provide assistance or resistance to the steering wheel; the electronic control unit 104 is connected to the torque sensor 101, the vehicle speed sensor 102 and the power-assist motor 103 respectively, and is used to determine whether the vehicle speed and torque meet the preset conditions, and when the preset conditions are met, the power-assist motor 103 in the electric power steering system is damped according to the vehicle speed.

[0062] The electric power steering system can determine whether to perform damping control through vehicle speed and torque.

[0063] In one embodiment of the present invention, the power-assisting motor 103 adopts an H-bridge driving mode. When the electronic control unit 104 performs damping control on the power-assisting motor 103 in the electric power steering system according to the vehicle speed, it is specifically used to: determine the duty cycle according to the vehicle speed; output a PWM signal to the lower arm of the H-bridge according to the duty cycle, and control the upper arm of the H-bridge to shut down.

[0064] It should be noted that, for other specific implementations of the electric power steering system according to the embodiment of the present invention, reference may be made to the above-mentioned control method of the electric power steering system.

[0065] The electric power steering system of the embodiment of the present invention can obtain the vehicle speed and steering wheel torque, and then determine whether to perform damping control according to the vehicle speed and steering wheel torque, thereby achieving a joint judgment through vehicle speed and torque, with stricter judgment conditions and clearer scenarios, thereby improving driving safety and reducing disturbances caused by misjudgment. In addition, the power-assisted motor adopts an H-bridge drive mode, and when performing damping control, the upper bridge arm of the H-bridge is controlled to be turned off, and the lower bridge arm of the H-bridge is controlled to be turned on, so that the power-assisted motor generates a damping torque according to the rotation of the steering wheel in the damping control mode, thereby preventing unpredictable movements due to misjudgment of the electric power-assisted steering system through a passive damping trigger mode.

[0066] Furthermore, the present invention provides a vehicle.

[0067] Figure 8 4 is a structural block diagram of a vehicle according to an embodiment of the present invention.

[0068] like Figure 8 As shown, a vehicle 200 includes the electric power steering system 100 described above.

[0069] The vehicle of the embodiment of the present invention can obtain the vehicle speed and steering wheel torque through the above-mentioned electric power steering system, and then judge whether to perform damping control according to the vehicle speed and steering wheel torque, so as to achieve a joint judgment through vehicle speed and torque, with stricter judgment conditions and clearer scenarios, thereby improving driving safety and reducing disturbances caused by misjudgment. In addition, the power-assisted motor adopts an H-bridge drive mode, and when performing damping control, the upper bridge arm of the H-bridge is controlled to be turned off, and the lower bridge arm of the H-bridge is controlled to be turned on, so that the power-assisted motor generates a damping torque according to the rotation of the steering wheel in the damping control mode, thereby preventing unpredictable movements due to misjudgment of the electric power-assisted steering system through a passive damping triggering mode.

[0070] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection portion with one or more wirings (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0071] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0072] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0073] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0074] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0075] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0076] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0077] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A control method for an electric power steering system, characterized in that: include: Get the vehicle speed and steering wheel torque; determining whether the vehicle speed and the torque meet preset conditions; If the conditions are met, damping control is performed on the power-assisted motor in the electric power-assisted steering system according to the vehicle speed; The preset conditions include: The vehicle speed is greater than a first preset speed threshold, the torque is less than a preset torque threshold, and is maintained for a preset time, and the preset torque threshold is less than the torque of the dead zone inflection point of the steering wheel; When the torque of the steering wheel increases from zero, the torque of the steering wheel is first in the damping control range, then in the hysteresis range, then in the dead zone, and then in the power assist range; In the hysteresis interval, the motor performs neither damping control nor power assist control, that is, the hysteresis interval is a transition interval between the damping control interval and the power assist interval, thereby preventing the motor from shaking due to switching between damping control and power assist control; the dead zone refers to the interval in which the power assist motor does not perform power assist, that is, the motor starts to provide power assist after the steering wheel torque reaches the inflection point of the dead zone, and damping control is set within the dead zone.

2. The control method of the electric power steering system according to claim 1, characterized in that: The power-assisted motor adopts an H-bridge driving mode, and the damping control of the power-assisted motor in the electric power steering system according to the vehicle speed includes: determining a duty cycle based on the vehicle speed; A PWM signal is output to the lower bridge arm of the H bridge according to the duty cycle, and the upper bridge arm of the H bridge is controlled to be turned off.

3. The control method of the electric power steering system according to claim 2, characterized in that: When the vehicle speed is greater than the first preset speed threshold and less than the second preset speed threshold, the vehicle speed is positively correlated with the duty cycle; When the vehicle speed is greater than or equal to the second preset speed threshold, the duty cycle is always 100%.

4. The control method of the electric power steering system according to claim 1, characterized in that: The first preset speed threshold has a value range of 70 to 90 km / h, and the preset time has a value range of 50 to 200 ms.

5. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the control method of the electric power steering system according to any one of claims 1 to 4 is implemented.

6. An electronic device, characterized in that: The invention 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 control method of the electric power steering system as claimed in any one of claims 1 to 4 is implemented.

7. An electric power steering system, characterized in that: include: Torque sensor, used to collect the torque of the vehicle steering wheel; A vehicle speed sensor, used to collect the vehicle speed; A power-assisting motor, the power-assisting motor is connected to the steering wheel and is used to provide power assistance or resistance for the steering wheel; an electronic control unit, the electronic control unit being connected to the torque sensor, the vehicle speed sensor and the power-assisted motor respectively, and being used to determine whether the vehicle speed and the torque meet preset conditions, and to perform damping control on the power-assisted motor in the electric power-assisted steering system according to the vehicle speed when the preset conditions are met; The preset conditions include: The vehicle speed is greater than a first preset speed threshold, the torque is less than a preset torque threshold, and is maintained for a preset time, and the preset torque threshold is less than the torque of the dead zone inflection point of the steering wheel; When the torque of the steering wheel increases from zero, the torque of the steering wheel is first in the damping control range, then in the hysteresis range, then in the dead zone, and then in the power assist range; In the hysteresis interval, the motor performs neither damping control nor power assist control, that is, the hysteresis interval is a transition interval between the damping control interval and the power assist interval, thereby preventing the motor from shaking due to switching between damping control and power assist control; the dead zone refers to the interval in which the power assist motor does not perform power assist, that is, the motor starts to provide power assist after the steering wheel torque reaches the inflection point of the dead zone, and damping control is set within the dead zone.

8. The electric power steering system according to claim 7, characterized in that: The power-assisted motor adopts an H-bridge driving mode, and the electronic control unit is specifically used to: determining a duty cycle based on the vehicle speed; A PWM signal is output to the lower bridge arm of the H bridge according to the duty cycle, and the upper bridge arm of the H bridge is controlled to be turned off.

9. A vehicle, characterized in that: Comprising the electric power steering system as claimed in claim 7 or 8.

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