Rear wheel steering machine, vehicle, locking control method and related equipment

Abstract

The embodiment of the invention discloses a rear wheel steering machine, a vehicle, a locking control method and related equipment, and the rear wheel steering machine comprises a diaphragm spring fixedly connected to a shell, a first friction plate connected with the outer end of the diaphragm spring, a transmission part used for driving a rack, and a second friction plate connected with the transmission part. And the induction coil is fixedly connected with the shell. When the current in the induction coil meets the locking condition, the first friction plate is attached to the second friction plate under the spring pressure effect of the diaphragm spring to achieve locking, and if the current in the induction coil is not zero, the diaphragm spring is subjected to the effect of a magnetic field generated by the induction coil, and the thrust of the diaphragm spring on the first friction plate is increased or decreased. When the current in the induction coil does not meet the locking condition, the induction coil generates a magnetic field to act on the diaphragm spring, so that the first friction plate is attracted away from the second friction plate, and locking is disconnected. And the current in the induction coil can control to disconnect the locking and realize quick locking, so that higher locking control efficiency is realized.

Description

Technical Field

[0001] This invention relates to the field of vehicles, and in particular to a rear-wheel steering system and vehicle, a locking control method and related equipment. Background Technology

[0002] Currently, rear-wheel steering systems are in mass production on many vehicle models. Their function of low-speed steering and high-speed same-direction steering can increase the turning radius at low speeds and improve stability at high speeds.

[0003] Rear-wheel steering systems commonly use a centrally mounted trapezoidal screw drive in conjunction with a rack and pinion position sensor to achieve rear-wheel steering. This type of steering system is simple in design and compact in structure. It can achieve mechanical self-locking through the trapezoidal screw, and can effectively lock at a designated position when the ECU diagnoses a fault and cuts off the motor power assist. However, this type of rear-wheel steering system suffers from low transmission efficiency and low locking efficiency. Summary of the Invention

[0004] To address the aforementioned technical problems, embodiments of this application provide a rear-wheel steering gear and vehicle, a locking control method, and related equipment, which can achieve high locking control efficiency.

[0005] This application provides a rear-wheel steering system, including:

[0006] A diaphragm spring fixed to the housing, and a first friction plate connected to the outer end of the diaphragm spring;

[0007] A transmission component for driving the rack, and a second friction plate connected to the transmission component;

[0008] An induction coil fixedly connected to the housing;

[0009] When the current in the induction coil meets the locking condition, the first friction plate is pressed against the second friction plate by the spring pressure of the diaphragm spring to achieve locking; if the current in the induction coil is not zero, the diaphragm spring is subjected to the magnetic field generated by the induction coil, which increases or decreases the thrust of the diaphragm spring on the first friction plate.

[0010] When the current in the induction coil does not meet the locking condition, the induction coil generates a magnetic field that acts on the diaphragm spring to pull the first friction plate away from the second friction plate, thereby breaking the locking.

[0011] Optionally, the transmission component includes a rotatably mounted ball screw nut, a ball screw drive pair screwed to the ball screw nut, and a drive unit that is throttle-connected to the ball screw nut; the ball screw drive pair is connected to a rack and pinion drive shaft; the drive unit includes a rotary drive unit and a belt drive unit located between the power output end of the rotary drive unit and the ball screw nut.

[0012] Optionally, the rotary drive unit is a motor; the belt drive unit includes a first pulley connected to the output shaft of the motor, a second pulley connected to the ball screw nut, and a belt disposed between the first pulley and the second pulley.

[0013] This application provides a locking control method, including:

[0014] The latching control current is determined based on the latching requirement; wherein, if there is no latching requirement, the latching control current is determined to be a first current that does not meet the latching conditions; if there is a latching requirement, the latching control current is determined to be a second current that meets the latching conditions.

[0015] The current in the induction coil of the rear wheel steering gear is controlled according to the locking control current.

[0016] Optionally, determining the latching control current based on the latching requirement includes:

[0017] If the motor controller is powered normally and is in a wake-up state, and has not obtained lock-up information, then the lock-up control current is determined to be the first current;

[0018] If the motor controller loses power or goes into sleep mode, the second current is determined to be a preset value and used as the lock-up control current.

[0019] If the motor controller is powered normally and is in a wake-up state, and locking at the locking position is required, then the actual value of the second current is determined according to the locking position, and used as the locking control current. The locking position is the end protection position of the rack or the actual position of the rack when a fault occurs.

[0020] Optionally, if the motor controller is powered normally and is in a wake-up state, and locking at the locking position is required, then determining the actual value of the second current based on the locking position as the locking control current includes:

[0021] If the motor controller is powered normally and is in a wake-up state, and locking at the locking position is required, then the control parameters are determined based on the actual movement parameters of the rack; the actual movement parameters include rack position, rack speed and rack acceleration, and the control parameters include proportional coefficient, integral coefficient and derivative coefficient.

[0022] Based on the control parameters and the difference between the locked position and the current position, the actual value of the second current is determined and used as the locking control current.

[0023] Optionally, if the motor controller is powered normally and is in an awakened state, and locking at the locking position is required, then the control parameters are determined based on the actual movement parameters of the rack, including:

[0024] If the motor controller is powered normally and is in a wake-up state, and locking at the locking position is required, then the actual movement parameters are fuzzified to obtain the input fuzzy value.

[0025] The output fuzzy value is determined based on the input fuzzy value and the fuzzy rule base;

[0026] The control parameters are determined based on the output fuzzy values.

[0027] This application provides a locking control device, including:

[0028] A latching control current determination unit is used to determine a latching control current based on latching requirements; wherein, if there is no latching requirement, the latching control current is determined to be a first current that does not meet the latching conditions; if there is a latching requirement, the latching control current is determined to be a second current that meets the latching conditions.

[0029] A control unit is configured to control the current in the induction coil of the rear wheel steering system according to any one of claims 1-3 based on the locking control current.

[0030] Optionally, the latching control current determination unit includes:

[0031] The first current determination unit is used to determine the locking control current as the first current if the motor controller is powered normally and is in a wake-up state, and has not obtained locking information.

[0032] The second current determination unit is used to determine the second current as a preset value and use it as the lock-up control current if the motor controller loses power or goes into sleep mode.

[0033] The third current determination unit is used to determine the actual value of the second current based on the locking position if the motor controller is powered normally and is in a wake-up state, and locking at the locking position is required, and to use the locking control current as the locking position. The locking position is the end protection position of the rack or the actual position of the rack when a fault is sent.

[0034] Optionally, the third current determining unit includes:

[0035] The control parameter determination unit is used to determine control parameters based on the actual movement parameters of the rack if the motor controller is powered normally and is in a wake-up state, and locking at the locking position is required; the actual movement parameters include rack position, rack speed and rack acceleration, and the control parameters include proportional coefficient, integral coefficient and derivative coefficient.

[0036] The current calculation unit is used to determine the actual value of the second current as the locking control current based on the control parameters and the difference between the locked position and the current position.

[0037] Optionally, the control parameter determining unit includes:

[0038] The fuzzification unit is used to fuzzify the actual movement parameters to obtain the input fuzzy value if the motor controller is powered normally and is in a wake-up state, and locking at the locking position needs to be implemented.

[0039] A fuzzy inference unit is used to determine an output fuzzy value based on the input fuzzy value and the fuzzy rule base.

[0040] The defuzzification unit is used to determine the control parameters based on the output fuzzy value.

[0041] This application provides a vehicle in which the aforementioned rear-wheel steering mechanism is provided.

[0042] This application discloses a computer device, which includes a processor and a memory:

[0043] The memory is used to store program code and transmit the program code to the processor;

[0044] The processor is configured to execute the locking control method as described in the first aspect according to the instructions in the program code.

[0045] This application discloses a computer-readable storage medium for storing a computer program, which, when executed by a processor, performs the locking control method as described in the first aspect.

[0046] This application provides a rear-wheel steering system and vehicle, a locking control method, and related equipment. The rear-wheel steering system includes a diaphragm spring fixed to a housing, a first friction plate connected to the outer end of the diaphragm spring, a transmission component for driving a rack, a second friction plate connected to the transmission component, and an induction coil fixed to the housing. When the current in the induction coil meets the locking condition, the first friction plate is pressed against the second friction plate by the spring pressure of the diaphragm spring to achieve locking. If the current in the induction coil is not zero, the diaphragm spring is subjected to the magnetic field generated by the induction coil, and its thrust on the first friction plate increases or decreases. When the current in the induction coil does not meet the locking condition, the induction coil generates a magnetic field that acts on the diaphragm spring to pull the first friction plate away from the second friction plate, thereby disengaging the lock. In other words, when there is no current in the induction coil, the first and second friction plates are put together to achieve locking. The current in the induction coil can control the first friction plate to move away from the second friction plate while it is in contact with the second friction plate to break the locking, or it can control the first friction plate to move quickly towards the first friction plate while it is moving away from the second friction plate to achieve fast locking. The larger the current in the induction coil, the faster this state changes, thus achieving higher locking control efficiency. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0048] Figure 1 and Figure 2 This is a schematic diagram of the structure of the rear wheel steering mechanism provided in an embodiment of this application;

[0049] Figure 3 A flowchart of a locking control method provided in an embodiment of this application;

[0050] Figure 4 This is a schematic diagram illustrating a specific process of locking control provided in an embodiment of this application;

[0051] Figure 5 A structural block diagram of a locking control device provided in an embodiment of this application;

[0052] Figure 6 This is a structural block diagram of a computer device for locking control provided in an embodiment of this application. Detailed Implementation

[0053] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0054] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0055] The following detailed description, in conjunction with the accompanying drawings, illustrates the specific implementation of a rear-wheel steering system, vehicle, locking control method, and related devices provided in this application through embodiments.

[0056] refer to Figure 1 and Figure 2 The diagram shown is a structural schematic of the rear wheel steering gear provided in an embodiment of this application, wherein... Figure 1 The rear wheel steering gear is in the locked-out state. Figure 2 The rear wheel steering mechanism is in a locked state. The rear wheel steering mechanism includes a diaphragm spring 2 fixed to the housing 11, a first friction plate 3 connected to the outer end of the diaphragm spring 2, a transmission component for driving the rack, a second friction plate 5 connected to the transmission component, and an induction coil 4 fixed to the housing 11.

[0057] The diaphragm spring 2 can be fixed to the housing 11 by fastening bolts 1. The diaphragm spring 2 can be annular, and its periphery can be fixed to the housing by several fastening bolts 1. The material of the diaphragm spring 2 can be a conductive material, such as a metal. The induction coil 4 can be a toroidal current coil winding, which can also be annular. The materials of the first friction plate 3 and the second friction plate 5 can be organic materials or inorganic materials, such as carbon ceramic friction plates.

[0058] The diaphragm spring 2 is disposed between the housing 11 and the first friction plate 3, providing an outward thrust to the first friction plate 3 so that the first friction plate 3 is moved away from the position where the housing 11 is fixed to the diaphragm spring 2. The first friction plate 3 is disposed between the diaphragm spring 2 and the second friction plate 5. In this way, in the locked state, the first friction plate 3 and the second friction plate 5 are in contact, which will suppress the rotational movement of the second friction plate 5, which is equivalent to suppressing the rotational movement of the transmission component, thereby achieving locking.

[0059] Specifically, when the current in the induction coil 4 meets the locking condition, the first friction plate 3 is pressed against the second friction plate 5 by the spring pressure of the diaphragm spring 2 to achieve locking. If the current in the induction coil 4 is not zero, the diaphragm spring 2 is affected by the magnetic field generated by the induction coil 4, causing the thrust of the diaphragm spring 2 on the first friction plate 3 to increase or decrease. That is, the induction coil 4 may not generate a magnetic field, in which case the current in the induction coil 4 is zero, and the first friction plate 3 is pressed against the second friction plate 5 by the spring pressure of the diaphragm spring 2; the induction coil 4 may also generate a magnetic field, in which case the current in the induction coil 4 is not zero, and the diaphragm spring 2 is affected by the magnetic field generated by the induction coil 4, which can increase the thrust of the first friction plate 3 to make the first friction plate 3 and the second friction plate 5 fit more tightly or more quickly, thereby improving the locking efficiency, or decrease the thrust of the first friction plate 3 to make the fit between the first friction plate 3 and the second friction plate 5 more stable, thereby improving vehicle stability.

[0060] Specifically, when the current in the induction coil 4 does not meet the locking condition, the magnetic field generated by the induction coil 4 will act on the diaphragm spring 2 to pull the first friction plate 3 away from the second friction plate 5, thereby disengaging the lock. At this time, the force exerted by the magnetic field generated by the induction coil 4 on the diaphragm spring 2 is greater than the original spring pressure of the diaphragm spring 2.

[0061] In summary, the locking mechanism designed using induction coil 4 and diaphragm spring 2 allows for locking control of the rear wheel steering system by controlling the current in induction coil 4 to meet or not meet locking conditions. The high current response speed of induction coil 4 allows for precise control and high locking efficiency. Furthermore, by controlling the current magnitude of induction coil 4, limit stops and hard protection functions at the end of the rack's travel can be implemented, achieving effective end-of-travel protection. This will be discussed in subsequent sections.

[0062] Currently, the self-locking mechanism achieved using trapezoidal screw drives suffers from low transmission efficiency, only about 25% to 30%. When matching vehicles with high-load rack-and-pinion forces, such as pure electric vehicles, a larger motor torque is required, increasing cost and space requirements. In this solution, the trapezoidal screw drive is replaced with a ball screw drive, improving the transmission efficiency to approximately 80% to 85%.

[0063] In this embodiment, the transmission component may include a rotatably mounted ball screw nut 10, a ball screw drive pair 6 screwed to the ball screw nut 10, and a drive unit that is pulverically connected to the ball screw nut 10. The ball screw drive pair 6 is connected to the rack drive shaft 12, so that the drive unit drives the ball screw nut 10 to rotate. The ball screw nut 10 converts the rotational motion into linear motion of the rack drive shaft 12 through the ball screw drive pair 6, so that the rack drive shaft 12 drives the connecting rod wheel, etc., through an external fork to achieve rear wheel steering. In addition, the rear wheel steering gear also includes a support bearing 13 fixedly connected to the housing 11.

[0064] The drive unit includes a rotary drive unit and a belt drive unit located between the power output end of the rotary drive unit and the ball screw nut 10. Thus, the power output end of the rotary drive unit can drive the ball screw nut 10 to rotate via the belt drive unit.

[0065] The rotary drive unit can be a motor 8, and the belt drive unit includes a first pulley 7 connected to the output shaft of the motor 8, a second pulley 9 connected to the ball screw nut 10, and a belt disposed between the first pulley 7 and the second pulley 9. In this way, the motor 8 can output torque, which drives the first pulley 7 to rotate via the output shaft of the motor 8. The belt drive achieves speed reduction and torque increase, transmitting the torque to the second pulley 9. The second pulley 9 and the ball screw nut 10 can be an interference fit, and the second pulley 9 drives the ball screw nut 10 to rotate. The second friction plate 5 can be connected to the end face of at least one of the second pulley 9 and the ball screw nut 10 to achieve locking control of the ball screw nut 10. The first pulley 7 can also be called a small pulley, and the second pulley 9 can also be called a large pulley.

[0066] This application provides a rear-wheel steering mechanism, which includes a diaphragm spring fixed to a housing, a first friction plate connected to the outer end of the diaphragm spring, a transmission component for driving a rack, a second friction plate connected to the transmission component, and an induction coil fixed to the housing. When the current in the induction coil meets the locking condition, the first friction plate is pressed against the second friction plate by the spring pressure of the diaphragm spring to achieve locking. If the current in the induction coil is not zero, the diaphragm spring is subjected to the magnetic field generated by the induction coil, and its thrust on the first friction plate increases or decreases. When the current in the induction coil does not meet the locking condition, the induction coil generates a magnetic field that acts on the diaphragm spring to pull the first friction plate away from the second friction plate, thereby disengaging the lock. In other words, when there is no current in the induction coil, the first and second friction plates are put together to achieve locking. The current in the induction coil can control the first friction plate to move away from the second friction plate while it is in contact with the second friction plate to break the locking, or it can control the first friction plate to move quickly towards the first friction plate while it is moving away from the second friction plate to achieve fast locking. The larger the current in the induction coil, the faster this state changes, thus achieving higher locking control efficiency.

[0067] Based on the rear-wheel steering system provided in the above embodiments, this application also provides a vehicle equipped with the aforementioned rear-wheel steering system.

[0068] Based on the rear wheel steering gear provided in the above embodiments, this application also provides a locking control method, see reference. Figure 3 The diagram shows a flowchart of a lock-up control method provided in an embodiment of this application. This method can be applied to a motor controller (ECU) and includes the following steps.

[0069] S101, determine the lock-up control current according to the lock-up requirements;

[0070] S102 controls the current in the induction coil of the rear wheel steering gear according to the locking control current.

[0071] In this embodiment, the locking control current can be determined according to the locking requirements. This locking control current controls the current in the induction coil, thereby changing the position of the first friction plate and switching the locking state. Specifically, the current in the induction coil can be adjusted to the locking control current. The magnitude of the induction coil current and its switching state can be controlled by the SBC (System Basis Chip) of the motor ECU.

[0072] The locking control current controls the locking torque, which is the torque exerted by the first friction plate on the second friction plate when the first and second friction plates are in contact. The locking torque determines the rack's movement parameters. The primary relationship between the locking control current and the locking torque can be determined as follows:

[0073] When the first and second friction plates are in contact, the torque (i.e., locking torque) exerted by the diaphragm spring on the second friction plate under the action of the induced magnetic field (which can be zero) can be expressed as:

[0074] M u =F u ·μ·L (1)

[0075] Where μ is the coefficient of friction between the two friction plates, L is the equivalent radius of the contact area between the two friction plates, i.e., the friction arm; F u The combined force exerted on the diaphragm spring by the magnetic field generated by the induction coil can be expressed as:

[0076] F u =F B +k·Δx (2)

[0077] Where k is the stiffness of the diaphragm spring, Δx is the amount of movement of the diaphragm spring compared to its initial rest position, and F B The force acting on a diaphragm spring only in a magnetic field is expressed as:

[0078] F B =α·B (3)

[0079] In the formula, α is the force coefficient under a fixed magnetic field strength, which is related to the designed material's vacuum permeability, the distance between the diaphragm spring and the induction coil, and the area of ​​the induction coil. B is the magnetic field strength generated by the current induction coil, which can be approximately written as follows:

[0080] B=β·N·S·I (4)

[0081] In the formula, β is the magnetic field coefficient, N is the number of turns in the coil winding, S is the relative area of ​​the winding core, and I is the magnitude of the current flowing through the induction coil (i.e., the locking control current); from this, it can be derived that the torque applied by the locking mechanism to the second friction plate in the energized state is:

[0082] M u =(αβ·N·S·I·B+k·Δx)μ·L (5)

[0083] The above relationship (5) can represent the first relationship, that is, different locking control currents I can determine different locking torques M. u .

[0084] The second relationship between the locking torque and the rack movement parameters can be expressed by the rack movement equation:

[0085]

[0086] In the formula, M motor For the motor output torque, Let ε be the pulley transmission ratio, ε be the transmission efficiency, R be the equivalent radius of the large pulley, and F be the transmission ratio. r F is the external load on the rack. s For internal friction, m R Let C be the rack mass, C be the rack damping, K be the rack stiffness, and s be the value of the rack. These are the rack displacement, rack speed, and rack acceleration, respectively, which can be detected by the steering gear rack position sensor and used as rack movement parameters. Thus, by controlling the locking torque M... u The movement state of the rack can be controlled, and the effect of the locking control current on the rack movement parameters can be determined by combining the aforementioned formulas (5) and (6).

[0087] In specific implementation, if there is no locking requirement, the locking control current is determined to be a first current that does not meet the locking condition; if there is a locking requirement, the locking control current is determined to be a second current that meets the locking condition. When the first current that does not meet the locking condition is applied to the induction coil, the magnetic field generated by the induction coil acts on the diaphragm spring, causing the diaphragm spring to pull the first friction plate away from the second friction plate. At this time, the force of the magnetic field on the diaphragm spring is in the first direction from the second friction plate to the first friction plate, which is greater than the original spring pressure of the diaphragm spring. When the second current that meets the locking condition is applied to the induction coil, the magnetic field generated by the induction coil acts on the diaphragm spring, causing the diaphragm spring to push the first friction plate towards the second friction plate. At this time, the force of the magnetic field on the diaphragm spring is in the first direction or the opposite direction. When the force is in the first direction, it is less than the original spring pressure of the diaphragm spring.

[0088] The first current, when applied to the induction coil, is used to maintain the lock-up open state and / or to switch from the lock-up open state. This first current typically has a large value. The magnetic field generated by the induction coil can attract the first friction plate away from the second friction plate, thus disengaging the lock-up. The motor then outputs torque to the rack with high transmission efficiency, and the direction of rotation is ready for operation. The first current used to switch from the lock-up open state can be equal to or slightly larger than the first current used to maintain the lock-up open state, so that the generated magnetic field can quickly attract the first friction plate away from the second friction plate.

[0089] In practice, if the motor ECU is powered normally and is in a wake-up state, and no lock-up information is received, it can be determined that there is no lock-up requirement, and the lock-up control current can be set to the first current. Lock-up information can be fault diagnosis information indicating a fault, or end-of-pipe protection information requiring end-of-pipe protection. Fault diagnosis information is generated when a fault is detected and lock-up is required, while end-of-pipe protection information is determined when the rack is detected at its end position and end-of-pipe protection is required. Furthermore, if an application layer command is received instructing the rack to move within a specified rack travel range, it indicates that end-of-pipe protection is not required, and end-of-pipe protection information can be considered not received. Alternatively, if the motor ECU completes its initialization and self-test without faults, it can be considered that fault diagnosis information has not been received.

[0090] When the second current is applied to the induction coil, it is used to maintain the locking state and / or to switch from the locked-out state to the locked state. This second current can have a small value, such as 0, in which case the induction coil generates no magnetic field or a small magnetic field. The effect of this magnetic field on the diaphragm spring is insufficient to pull the first friction plate away from the second friction plate, thus maintaining the locking state or achieving the switch to the locked state. The second current can be a current in the same direction as the first current, thereby reducing the pushing force of the diaphragm spring on the first friction plate, causing the first friction plate to slowly adhere to the second friction plate, achieving smooth locking. Alternatively, the second current can be a current in the opposite direction to the first current, and the magnetic field it generates pushes the first friction plate to adhere to the second friction plate, causing the first friction plate to quickly adhere to the second friction plate, achieving rapid switching of the locking state and improving locking control efficiency. When the second current is a current opposite to the first current, it can provide pressure between the first and second friction plates, ensuring a tight fit between them and improving the reliability of the locking state.

[0091] In actual operation, if the motor ECU is in sleep mode or power supply is lost, it can be determined that there is a first locking requirement. At this time, the second current can be a preset value, which can be a small value, such as 0. That is, the locking control current is the preset value. At this time, the induction coil generates no magnetic field or generates a small magnetic field. The first friction plate and the second friction plate are pressed together under the spring pressure of the diaphragm spring, which inhibits the transmission of the transmission components, that is, inhibits the rotation of the ball screw nut.

[0092] If the motor controller is powered normally and is in a wake-up state, and needs to implement locking at the locking position, then the second locking requirement can be determined. At this time, the actual value of the second current can be determined according to the locking position. The actual value of the second current can change with time, that is, the locking control current is determined as the actual value of the second current according to the locking position.

[0093] The aforementioned locking position can be either the end protection position or the actual position of the rack when a fault is transmitted. The end protection position is the end position of the rack, and the rack's travel should not exceed this end position, meaning that locking is required at this end position. The end protection position is determined based on the end protection information. The actual position of the rack when a fault is transmitted is when the motor controller's diagnostic function is activated and a fault is detected, thus requiring locking at the current position. This current position is the actual position of the rack when a fault is transmitted, and the actual position of the rack when a fault is transmitted is determined based on the fault diagnosis information.

[0094] As an example, the latch-up control current I can be expressed as:

[0095]

[0096] That is, when the system is powered off or the ECU is in sleep mode, the current in the induction coil can be 0. At this time, the diaphragm spring pushes the first friction plate to contact the second friction plate, achieving locking. When there is no need for locking, the current in the induction coil is a larger first current I. S This causes the diaphragm spring to quickly pull the first friction plate away from the second friction plate, locking and stopping the circuit. In case of system failure or end-of-line protection requirements, the actual value of the second current I can be determined based on the locking position. δ This ensures locking in this scenario.

[0097] refer to Figure 4 The diagram shown is a schematic of a specific locking control process provided in an embodiment of this application. First, it is determined that the motor controller is powered normally. If so, it is further determined whether a locking indication is obtained. If not, it indicates that the electrode controller is out of power or in a dormant state. Then, the induction coil can be controlled by a preset value to make the rear wheel steering gear enter the locking state or maintain the locking state.

[0098] When the motor controller is confirmed to be powered normally, in the process of determining whether to obtain locking information, it is possible to first determine whether to obtain fault diagnosis information. If a fault is diagnosed and there is a locking requirement at the current position due to the fault, then the induction coil can be controlled by the actual value of the second current to push the diaphragm spring to enter the locking state. Otherwise, the current situation can be maintained and further determination can be made to obtain end protection information.

[0099] If end protection information is obtained through the rack position sensor, it means that the rack is near the end and end limit protection needs to be implemented. In this case, the actual value of the second current can be used to control the induction coil to push the diaphragm spring into the locking state to prevent the rack travel from overshooting. If no end protection information is obtained, it means that no locking information is obtained, i.e., there is no locking requirement. In this case, the first current can be used to control the induction coil to attract the diaphragm spring to realize the disconnection of the locking state.

[0100] In practical implementation, the pushing and pulling of the diaphragm spring can be achieved by the locking mechanism control module, which can be located in the SBC. During the determination of the locking control current, since there are different states between the diaphragm spring friction plate and the rotating friction plate, such as gap, engagement, and increased clamping force, the transition between each state can be smoothly achieved by implementing ECU current closed-loop control to prevent torque abrupt changes that could cause rack position jitter or noise. For example, the locking control current can be determined by PID control to dynamically adjust the control parameters under different states. These control parameters can also be called PID parameters or PID values.

[0101] In determining the actual value of the second current based on the locking position, control parameters can be determined based on the actual movement parameters of the rack. Then, based on the control parameters and the difference between the locking position and the current position, the actual value of the second current is determined as the locking control current. The actual movement parameters include rack position, rack speed, and rack acceleration, while the control parameters include proportional coefficient, integral coefficient, and derivative coefficient. The actual movement parameters can be obtained through the steering gear rack position sensor.

[0102] Specifically, the actual value I of the second current δ It can be represented as:

[0103]

[0104] Among them, K p K i K d These are the proportional coefficient, integral coefficient, and derivative coefficient, which are determined based on the rack position, rack speed, and rack acceleration. Δδ is the difference between the locked position and the current position. Specifically, in a fault-free state, Δδ is the difference between the current position and the end protection position; in a severe fault state, Δδ is the difference between the current position and the actual rack position when the fault was sent. t is the time parameter.

[0105] In determining the control parameters based on the actual movement parameters of the rack, fuzzy inference (such as the Mamdani method) can be used to calculate the control parameters. This allows for dynamic adjustment of the control parameters using fuzzy logic principles, smoothly transitioning between different states to ensure no rack jitter or noise occurs during locking. Specifically, the actual movement parameters of the rack can be fuzzified to obtain input fuzzy values. The output fuzzy values ​​are then determined based on the input fuzzy values ​​and a fuzzy rule base, and finally, the control parameters are determined based on the output fuzzy values.

[0106] Input fuzzy values ​​can include fault status St, rack position s, and rack speed. and rack acceleration Their domains are S t= 0 or 1 (0 for no state, 1 for severe fault), s∈[-P, P], P, Q, and M are the absolute limits of the rack displacement, velocity, and acceleration, respectively; the membership function in fuzzification uses the Gaussian function (Gaussmf); the fuzzy linguistic sets for rack displacement, rack velocity, and rack acceleration can be defined as [NB, NS, ZO, PS, PB], representing negative large, negative small, zero, positive small, and positive large, respectively; the fuzzy output is K. p K i K d Their domains are all [0,1], and the set of fuzzy language rules is also [NB,NS,ZO,PS,PB], which represent negative large, negative small, zero, positive small and positive large, respectively.

[0107] Because of the existence of three inputs and three outputs, the fuzzy rule base can be obtained through classification training using supervised decision trees in machine learning. Its overall control rule can be expressed as "ifS". t and s and and then K p and K i and K d Each input feature is classified into two classes using if-else conditional statements. The principles of decision trees will not be explained in detail here.

[0108] The rule base should primarily achieve the following effects: the closer to the rack end protection position, the larger the required PID value, to facilitate rapid elimination of friction plate gap space; in severe fault conditions, the PID value needs to be larger than in fault-free conditions, to facilitate faster braking and locking at the fault position; the larger the rack speed and acceleration values, the larger the required PID value, to achieve rapid braking and locking, and reduce position errors; under the same fault condition, it is also necessary to monitor the consistency of the rack acceleration cycle before and after; after a step phenomenon, the PID value needs to be appropriately reduced (when the friction plates are just in contact, to reduce vibration).

[0109] Therefore, based on the fuzzy rule base and fuzzy reasoning process formulated by the decision tree, the dynamic PID value can be adjusted relatively smoothly, accurately and reliably achieving the work requirements of end protection and fault current position locking at the same time.

[0110] This application provides a rear-wheel steering gear with high transmission efficiency and locking capability. The transmission pair adopts a high-efficiency ball screw drive, and the locking device is designed using an induction coil and a diaphragm spring. Combined with the principle of electromagnetic induction, the engagement and disengagement of the friction plate pair are controlled to meet the locking requirements in different scenarios. By using this locking device and locking control method, it can ensure high-efficiency transmission under normal working conditions, reduce motor output, optimize motor selection and cost, and ensure locking function in special scenarios such as the end of the stroke or power failure.

[0111] Based on the above locking control method, this application also provides a locking control device, see reference. Figure 5 The diagram shown is a structural block diagram of a locking control device provided in an embodiment of this application, which can be applied to a motor controller and includes:

[0112] The latching control current determination unit 110 is used to determine the latching control current according to the latching requirement; wherein, if there is no latching requirement, the latching control current is determined to be a first current that does not meet the latching condition; if there is a latching requirement, the latching control current is determined to be a second current that meets the latching condition.

[0113] Control unit 120 is used to control the current in the induction coil of the rear wheel steering gear according to the locking control current.

[0114] Optionally, the latching control current determination unit includes:

[0115] The first current determination unit is used to determine the locking control current as the first current if the motor controller is powered normally and is in a wake-up state, and has not obtained locking information.

[0116] The second current determination unit is used to determine the second current as a preset value and use it as the lock-up control current if the motor controller loses power or goes into sleep mode.

[0117] The third current determination unit is used to determine the actual value of the second current based on the locking position if the motor controller is powered normally and is in a wake-up state, and locking at the locking position is required, and to use the locking control current as the locking position. The locking position is the end protection position of the rack or the actual position of the rack when a fault is sent.

[0118] Optionally, the third current determining unit includes:

[0119] The control parameter determination unit is used to determine control parameters based on the actual movement parameters of the rack if the motor controller is powered normally and is in a wake-up state, and locking at the locking position is required; the actual movement parameters include rack position, rack speed and rack acceleration, and the control parameters include proportional coefficient, integral coefficient and derivative coefficient.

[0120] The current calculation unit is used to determine the actual value of the second current as the locking control current based on the control parameters and the difference between the locked position and the current position.

[0121] Optionally, the control parameter determining unit includes:

[0122] The fuzzification unit is used to fuzzify the actual movement parameters to obtain the input fuzzy value if the motor controller is powered normally and is in a wake-up state, and locking at the locking position needs to be implemented.

[0123] A fuzzy inference unit is used to determine an output fuzzy value based on the input fuzzy value and the fuzzy rule base.

[0124] The defuzzification unit is used to determine the control parameters based on the output fuzzy value.

[0125] Please see Figure 6 , Figure 6 This application provides a structural block diagram of a computer device for locking control. The computer device includes a processor 710 and a memory 720.

[0126] The memory 720 is used to store program code and transmit the program code to the processor 710;

[0127] The processor 710 is used to execute the locking control method described in any of the above embodiments according to the instructions in the program code.

[0128] This application also discloses a computer-readable storage medium for storing a computer program, which, when executed by a processor, performs the locking control method described in any of the above embodiments.

[0129] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that all or part of the steps in the methods of the above embodiments can be implemented by means of software plus a general-purpose hardware platform. Based on this understanding, the technical solution of this application can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as a read-only memory (ROM) / RAM, magnetic disk, optical disk, etc., including several instructions to cause a computer device (which may be a personal computer, a server, or a network communication device such as a router) to execute the methods described in various embodiments or some parts of the embodiments of this application.

[0130] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple, and relevant parts can be referred to the method section.

[0131] It should also be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0132] The above description is merely a preferred embodiment of this application. Although this application has disclosed preferred embodiments above, it is not intended to limit this application. Any person skilled in the art can make many possible variations and modifications to the technical solutions of this application using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the scope of the technical solutions of this application. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this application without departing from the content of the technical solutions of this application shall still fall within the protection scope of the technical solutions of this application.

Claims

1. A rear-wheel steering gear, characterized in that, include: A diaphragm spring fixed to the housing, and a first friction plate connected to the outer end of the diaphragm spring; A transmission component for driving the rack, and a second friction plate connected to the transmission component; An induction coil fixedly connected to the housing; When the current in the induction coil meets the locking condition, the first friction plate is pressed against the second friction plate by the spring pressure of the diaphragm spring to achieve locking; if the current in the induction coil is not zero, the diaphragm spring is subjected to the magnetic field generated by the induction coil, which increases or decreases the thrust of the diaphragm spring on the first friction plate. When the current in the induction coil does not meet the locking condition, the induction coil generates a magnetic field that acts on the diaphragm spring to pull the first friction plate away from the second friction plate, thereby breaking the locking.

2. The rear wheel steering gear according to claim 1, characterized in that, The transmission component includes a rotatably mounted ball screw nut, a ball screw drive pair screwed to the ball screw nut, and a drive unit that is pulsatorically connected to the ball screw nut; the ball screw drive pair is connected to a rack and pinion drive shaft; the drive unit includes a rotary drive unit and a belt drive unit located between the power output end of the rotary drive unit and the ball screw nut.

3. The rear wheel steering gear according to claim 2, characterized in that, The rotary drive unit is a motor; the belt drive unit includes a first pulley connected to the output shaft of the motor, a second pulley connected to the ball screw nut, and a belt disposed between the first pulley and the second pulley.

4. A locking control method, characterized in that, include: The latching control current is determined based on the latching requirement; wherein, if there is no latching requirement, the latching control current is determined to be a first current that does not meet the latching conditions; if there is a latching requirement, the latching control current is determined to be a second current that meets the latching conditions. The current in the induction coil of the rear wheel steering gear according to any one of claims 1-3 is controlled by the locking control current.

5. The method according to claim 4, characterized in that, Determining the latching control current based on latching requirements includes: If the motor controller is powered normally and is in a wake-up state, and has not obtained lock-up information, then the lock-up control current is determined to be the first current; If the motor controller loses power or goes into sleep mode, the second current is determined to be a preset value and used as the lockout control current. If the motor controller is powered normally and is in a wake-up state, and locking at the locking position is required, then the actual value of the second current is determined according to the locking position, and used as the locking control current. The locking position is the end protection position of the rack or the actual position of the rack when a fault occurs.

6. The method according to claim 5, characterized in that, If the motor controller is powered normally and is in a wake-up state, and locking at a lock-up position is required, then the actual value of the second current is determined based on the lock-up position as the lock-up control current, including: If the motor controller is powered normally and is in a wake-up state, and locking at the locking position is required, then the control parameters are determined based on the actual movement parameters of the rack; the actual movement parameters include rack position, rack speed and rack acceleration, and the control parameters include proportional coefficient, integral coefficient and derivative coefficient. Based on the control parameters and the difference between the locked position and the current position, the actual value of the second current is determined and used as the locking control current.

7. The method according to claim 6, characterized in that, If the motor controller is powered normally and is in an awake state, and locking at the locking position is required, then the control parameters are determined based on the actual movement parameters of the rack, including: If the motor controller is powered normally and is in a wake-up state, and locking at the locking position is required, then the actual movement parameters are fuzzified to obtain the input fuzzy value. The output fuzzy value is determined based on the input fuzzy value and the fuzzy rule base; The control parameters are determined based on the output fuzzy values.

8. A locking control device, characterized in that, include: A latching control current determination unit is used to determine a latching control current based on latching requirements; wherein, if there is no latching requirement, the latching control current is determined to be a first current that does not meet the latching conditions; if there is a latching requirement, the latching control current is determined to be a second current that meets the latching conditions. A control unit is configured to control the current in the induction coil of the rear wheel steering system according to any one of claims 1-3 based on the locking control current.

9. The apparatus according to claim 8, characterized in that, The latching control current determination unit includes: The first current determination unit is used to determine the locking control current as the first current if the motor controller is powered normally and is in a wake-up state, and has not obtained locking information. The second current determination unit is used to determine the second current as a preset value and use it as the lock-up control current if the motor controller loses power or goes into sleep mode. The third current determination unit is used to determine the actual value of the second current based on the locking position if the motor controller is powered normally and is in a wake-up state, and locking at the locking position is required, and to use the locking control current as the locking position. The locking position is the end protection position of the rack or the actual position of the rack when a fault is sent.

10. A vehicle, characterized in that, The vehicle is equipped with a rear-wheel steering mechanism as described in any one of claims 1-3.

11. A computer device, characterized in that, The computer device includes a processor and memory: The memory is used to store program code and transmit the program code to the processor; The processor is configured to execute the locking control method according to any one of claims 4-7 according to the instructions in the program code.

12. A computer-readable storage medium, characterized in that, The computer-readable storage medium is used to store a computer program, which, when executed by a processor, is used to perform the locking control method according to any one of claims 4-7.

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