Locked-rotor protection method of steering system, steering system and electric vehicle

Abstract

The invention provides a locked-rotor protection method of a steering system, the steering system and an electric vehicle, and is applied to the technical field of electric vehicles. The protection method is used for adjusting torque output by a steering motor to protect the steering system in the process that the steering motor of the steering system drives a tie rod to move to drive wheels of the electric vehicle to steer. The protection method comprises the steps that after the first moment when a tie rod starts to move towards one side and before the second moment when the tie rod moves towards one side to a preset position, a steering motor is controlled to output first torque, and the rotating speed of the steering motor is controlled to be larger than the preset rotating speed; after the second moment, when it is detected that the first torque output by the steering motor is larger than the preset torque and the rotating speed of the steering motor is smaller than or equal to the preset rotating speed, the steering motor is controlled to reduce the output first torque. Therefore, stalling of the steering motor is relieved or avoided, and the steering system is protected.

Description

Technical Field

[0001] The present application relates to the technical field of electric vehicles, and in particular to a steering system stall protection method, a steering system, and an electric vehicle. Background Art

[0002] During wheel steering in electric vehicles, the steering system typically controls the wheels. Specifically, the steering motor rotates to drive the tie rods, which in turn drives the wheels. In some cases, the tie rods can over-stroke (stroke refers to the effective range of motion), potentially causing both ends of the tie rods to collide with the steering system housing, leading to a stall in the steering motor. This stall can also damage steering system components (such as belts and the steering motor). Summary of the Invention

[0003] An embodiment of the present application provides a steering system stall protection method, a steering system, and an electric vehicle. When the steering motor of the steering system drives the tie rod to move to turn the wheels of the electric vehicle, the torque output by the steering motor is adjusted to protect the steering system.

[0004] In a first aspect, embodiments of the present application provide a method for protecting a steering system from stalling. The method is used to adjust the torque output by the steering motor to protect the steering system during the process of the steering motor driving the tie rod to move and turn the wheels of the electric vehicle. The method includes:

[0005] After a first moment when the tie rod starts to move to one side and before a second moment when the tie rod moves to one side to a preset position, controlling the steering motor to output a first torque and controlling the speed of the steering motor to be greater than a preset speed;

[0006] After the second moment, when it is detected that the first torque output by the steering motor is greater than the preset torque and the rotation speed of the steering motor is less than or equal to the preset rotation speed, the steering motor is controlled to reduce the output first torque.

[0007] In this embodiment, while the steering motor drives the tie rod to steer the wheels of the electric vehicle, the tie rod is driven to one side and to a preset position by controlling the steering motor to output a first torque and maintaining the steering motor speed above a preset speed. Subsequently, by detecting that the first torque output by the steering motor is greater than the preset torque and the steering motor speed is less than or equal to the preset speed, overstroke of the tie rod or collision of one end of the tie rod with the housing is detected. In this case, the steering motor is controlled to reduce the first torque output to alleviate or prevent steering motor stall. This, in turn, addresses issues such as a sharp increase in steering motor current, a rapid increase in steering motor temperature, and mechanical damage caused by stalling, thereby protecting the steering system.

[0008] In an embodiment of the first aspect, the protection method further includes: after the first moment and before the second moment, first controlling the speed of the steering motor to increase from zero, and then controlling the speed of the steering motor to decrease.

[0009] In this embodiment, the steering motor is first controlled to increase its rotational speed from zero to control the driving tie rod to start moving to one side, and then the steering motor is controlled to decrease its rotational speed to control the tie rod to reduce its movement speed before moving to one side to a preset position. This makes the movement speed of the tie rod smaller when approaching the preset position, making it easier to subsequently control the tie rod to stop moving.

[0010] In an embodiment of the first aspect, the protection method specifically includes: controlling the rotation speed of the steering motor to decrease to zero at or before the second moment.

[0011] In this embodiment, the steering motor speed is controlled to be reduced to zero before the tie rod moves to the preset position, so that the tie rod is controlled to stop moving before the tie rod moves to the preset position, thereby avoiding overstroke of the tie rod and causing the steering motor to stall.

[0012] In an embodiment of the first aspect, the protection method further includes: after the second moment, when it is detected that the rate of change of the current of the steering motor is greater than a preset current rate of change, controlling the steering motor to reduce the output first torque.

[0013] In this embodiment, the rate of change of the steering motor's current can indicate whether the steering motor is stalled or nearly stalled. This is detected by detecting whether the rate of change of the steering motor's current is greater than a preset rate of change. In this case, the steering motor is controlled to reduce the first torque output, thereby alleviating or preventing stalling and protecting the steering system.

[0014] In an embodiment of the first aspect, the protection method further includes: after the second moment, when it is detected that the temperature change rate of the steering motor is greater than a preset temperature change rate, controlling the steering motor to reduce the output first torque.

[0015] In this embodiment, the rate of change of the steering motor's temperature can indicate whether the steering motor is stalled or nearly stalled. This is detected by detecting if the rate of change of the steering motor's temperature is greater than a preset temperature change rate. In this case, the steering motor is controlled to reduce its first output torque, thereby alleviating or preventing stalling of the steering motor and simultaneously reducing the temperature of the steering system, thereby protecting the steering system.

[0016] In an embodiment of the first aspect, the protection method further includes: after the second moment, when it is detected that the first torque output by the steering motor is greater than the preset torque and the speed of the steering motor is zero, controlling the steering motor to stop outputting the first torque.

[0017] In this embodiment, automatic detection of a steering motor stall is achieved by detecting that the first torque output by the steering motor is greater than a preset torque and the steering motor speed is zero. In this case, the steering motor is controlled to stop outputting the first torque, preventing the steering motor from being continuously stalled. This addresses issues such as a sharp increase in steering motor current, a rapid increase in steering motor temperature, and mechanical damage caused by a stall, thereby protecting the steering system.

[0018] In an embodiment of the first aspect, the protection method further includes: after the second moment, when it is detected that the first torque output by the steering motor is greater than the preset torque and the speed of the steering motor is less than or equal to the preset speed, controlling the steering motor to output a second torque in the opposite direction to the first torque.

[0019] In this embodiment, detection of tie rod overstroke or collision with the housing is achieved by detecting whether the first torque output by the steering motor is greater than a preset torque and the steering motor speed is less than or equal to a preset speed. In this case, the steering motor is controlled to output a second torque in the opposite direction of the first torque to control the tie rod to move to the other side, thereby preventing one end of the tie rod from colliding with the housing or alleviating steering motor stall caused by collision, thereby protecting the steering system.

[0020] In an embodiment of the first aspect, the protection method specifically includes: after the second moment, the smaller the rotation speed of the steering motor is, the larger the reduced first torque output by the steering motor is controlled.

[0021] In this embodiment, the smaller the speed of the steering motor, the larger the first torque after the reduction output of the steering motor is controlled to be, so that the first torque after the reduction output of the steering motor can be flexibly controlled according to the speed of the steering motor, and the steering motor can be alleviated or avoided from being blocked under different speeds of the steering motor, thereby protecting the steering system.

[0022] In an embodiment of the first aspect, the protection method specifically includes: after the second moment, the greater the detected rate of change of the current of the steering motor or the greater the rate of change of the temperature of the steering motor, the smaller the first torque after the steering motor output is controlled to be reduced.

[0023] In this embodiment, the greater the rate of change of the current of the steering motor or the rate of change of the temperature of the steering motor, the smaller the first torque after the reduction output of the steering motor is controlled, so that the first torque after the reduction output of the steering motor can be flexibly controlled according to the rate of change of the current of the steering motor or the rate of change of the temperature of the steering motor, so that the steering motor can be alleviated or avoided from stalling under different conditions of the rate of change of the current or the rate of change of the temperature, thereby protecting the steering system.

[0024] In an embodiment of the first aspect, the protection method specifically includes: after the second moment, the smaller the detected rotation speed of the steering motor is, the larger the second torque output by the steering motor is controlled.

[0025] In this embodiment, the smaller the speed of the steering motor, the larger the second torque output by the steering motor is controlled to be, thereby realizing flexible control of the second torque output by the steering motor according to the speed of the steering motor, and realizing that when the speed of the steering motor is different, the tie rod can be driven to move to the other side, thereby alleviating or avoiding steering motor jamming and protecting the steering system.

[0026] In an embodiment of the first aspect, the protection method specifically includes: after the second moment, the greater the detected rate of change of the current of the steering motor or the rate of change of the temperature of the steering motor, the greater the second torque output by the steering motor is controlled.

[0027] In this embodiment, the greater the rate of change of the current of the steering motor or the rate of change of the temperature of the steering motor, the greater the second torque output by the steering motor is controlled, so that the second torque output by the steering motor can be flexibly controlled according to the rate of change of the current of the steering motor or the rate of change of the temperature of the steering motor, and the tie rod can be driven to move to the other side under different conditions of the rate of change of the current or the rate of change of the temperature, thereby alleviating or avoiding the jam of the steering motor and protecting the steering system.

[0028] In an embodiment of the first aspect, the protection method specifically includes: receiving a displacement signal from a displacement sensor, and acquiring a displacement indicated by the displacement signal as a displacement of the tie rod.

[0029] In this embodiment, by directly using the displacement indicated by the displacement signal from the displacement sensor as the displacement of the tie rod, the displacement of the tie rod can be quickly acquired, which is beneficial for subsequently determining the displacement of the tie rod based on the displacement of the tie rod to control the steering motor.

[0030] In an embodiment of the first aspect, the protection method specifically includes: calculating the displacement of the tie rod according to the steering motor speed indicated by the speed signal of the steering motor.

[0031] In this embodiment, by detecting the speed signal of the steering motor and calculating the displacement of the tie rod according to the steering motor speed indicated by the speed signal, the displacement of the tie rod is accurately obtained, which is conducive to subsequently determining the displacement of the tie rod based on the displacement of the tie rod to accurately control the steering motor.

[0032] In a second aspect, an embodiment of the present application provides a steering system, which includes a steering motor, a tie rod, and a steering controller. The steering motor is used to drive the tie rod to move and drive the wheels of the electric vehicle to steer. The steering controller is used to:

[0033] After a first moment when the tie rod starts to move to one side and before a second moment when the tie rod moves to one side to a preset position, controlling the steering motor to output a first torque and controlling the speed of the steering motor to be greater than a preset speed;

[0034] After the second moment, when it is detected that the first torque output by the steering motor is greater than the preset torque and the rotation speed of the steering motor is less than or equal to the preset rotation speed, the steering motor is controlled to reduce the output first torque.

[0035] In an embodiment of the second aspect, the steering controller is further used to: after the second moment, when it is detected that the first torque output by the steering motor is greater than the preset torque and the speed of the steering motor is zero, control the steering motor to stop outputting the first torque.

[0036] In a third aspect, an embodiment of the present application provides an electric vehicle, comprising a steering system, the steering system comprising a steering motor, a tie rod, and a steering controller, wherein the steering motor is configured to drive the tie rod to move and thereby steer the wheels of the electric vehicle. The steering controller is configured to:

[0037] After a first moment when the tie rod starts to move to one side and before a second moment when the tie rod moves to one side to a preset position, controlling the steering motor to output a first torque and controlling the speed of the steering motor to be greater than a preset speed;

[0038] After the second moment, when it is detected that the first torque output by the steering motor is greater than the preset torque and the rotation speed of the steering motor is less than or equal to the preset rotation speed, the steering motor is controlled to reduce the output first torque.

[0039] In an embodiment of the third aspect, the steering controller is further used to: after the second moment, when it is detected that the first torque output by the steering motor is greater than the preset torque and the speed of the steering motor is zero, control the steering motor to stop outputting the first torque.

[0040] For the supplementary and technical effects of the solutions provided in the second and third aspects above, please refer to the corresponding description of the first aspect and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A schematic diagram of an electric vehicle provided in an embodiment of the present application is shown;

[0042] Figure 2 A schematic diagram of an electric vehicle architecture provided by an embodiment of the present application is shown;

[0043] Figure 3 A schematic diagram of a steering system provided in an embodiment of the present application is shown;

[0044] Figure 4 A schematic diagram showing a collision between the left end of a tie rod and a housing provided by an embodiment of the present application is shown;

[0045] Figure 5 A schematic diagram showing the maximum movable range of a tie rod provided in an embodiment of the present application is shown;

[0046] Figure 6 A schematic diagram showing the moving position of a tie rod provided in an embodiment of the present application;

[0047] Figure 7 A schematic diagram showing a timing relationship of a first torque provided in an embodiment of the present application is shown;

[0048] Figure 8 A schematic diagram showing the timing relationship of the moving speed of a tie rod provided in an embodiment of the present application is shown;

[0049] Figure 9 A schematic diagram showing a timing relationship of another first torque provided in an embodiment of the present application is shown;

[0050] Figure 10 A timing diagram of the torque output by a steering motor provided in an embodiment of the present application is shown;

[0051] Figure 11 A schematic diagram of a steering controller provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0052] The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings.

[0053] In the embodiments of this application, prefixes such as "first" and "second" are used only to distinguish different description objects and have no limiting effect on the position, order, priority, quantity, or content of the described objects. The use of prefixes such as ordinal numbers to distinguish description objects in the embodiments of this application does not constitute a limitation on the described objects. For a statement of the described objects, please refer to the description in the context of the claims or embodiments, and the use of such prefixes should not constitute an unnecessary limitation.

[0054] During wheel steering in electric vehicles, the steering system typically controls the wheels. Specifically, the steering motor rotates to drive the tie rod, thereby driving the wheels. In some cases, the tie rod overstrokes. If this overstroke is not detected and the tie rod's movement is not quickly controlled, the ends of the tie rod can collide with the steering system housing, causing the steering motor to stall. This stall can also damage steering system components (such as the belt and steering motor).

[0055] In view of this, an embodiment of the present application provides a steering system jam protection method, a steering system and an electric vehicle. The protection method includes: after a first moment when the tie rod starts to move to one side and before a second moment when the tie rod moves to one side to a preset position, controlling the steering motor to output a first torque and controlling the speed of the steering motor to be greater than a preset speed; after the second moment, when it is detected that the first torque output by the steering motor is greater than the preset torque and the speed of the steering motor is less than or equal to the preset speed, controlling the steering motor to reduce the output first torque, thereby protecting the steering system.

[0056] See also Figure 1 , Figure 1 A schematic diagram of an electric vehicle is shown. Figure 1 As shown, the electric vehicle 100 includes a rear-wheel steering system 110 , a front-wheel steering system 120 , a vehicle controller 130 and a power battery 140 .

[0057] The rear-wheel steering system 110 is used to drive the rear wheels of the electric vehicle 100. The front-wheel steering system 120 is used to drive the front wheels of the electric vehicle 100. The vehicle controller 130 is used to control the rear-wheel steering system 110 and the front-wheel steering system 120 of the electric vehicle 100. The power battery 140 is used to provide power to the rear-wheel steering system 110 and the front-wheel steering system 120.

[0058] See also Figure 2 , Figure 2 Schematic diagram of an electric vehicle architecture is shown, wherein the electric vehicle 100 further includes rear wheels 150 and front wheels 160 .

[0059] like Figure 2 As shown, the rear-wheel steering system 110 includes a steering motor 111 , a steering controller 112 and a rear-wheel steering gear 113 .

[0060] The steering motor 111 is used to provide driving force for steering the rear wheels 150 of the electric vehicle 100. The steering controller 112 is used to control the torque output by the steering motor 111. The rear wheel steering gear 113 is used to convert the rotational motion of the torque output by the steering motor 111 into linear motion to drive the rear wheels of the electric vehicle.

[0061] During the steering process of the electric vehicle 100, the steering controller 112 receives a steering angle signal from the vehicle controller 130 and receives a steering angle signal from the power battery 140 (eg, Figure 1 The steering motor 111 outputs torque according to the steering angle indicated by the steering angle signal.

[0062] Among them, the torque output by the steering motor 111 includes forward torque and reverse torque. When the steering motor 111 outputs forward torque and outputs reverse torque, the steering direction of the rear wheels of the electric vehicle 100 is opposite. For example, when the steering motor 111 outputs forward torque, the rear wheels of the electric vehicle 100 turn to the right, and when it outputs reverse torque, the rear wheels of the electric vehicle 100 turn to the left.

[0063] Continue to see Figure 2 The front wheel steering system 120 includes a steering motor 121 , a steering controller 122 and a front wheel steering gear 123 .

[0064] The steering motor 121 is used to provide driving force for steering the front wheels 160 of the electric vehicle 100. The steering controller 122 is used to control the torque output by the steering motor 121. The front wheel steering gear 123 is used to convert the rotational motion of the torque output by the steering motor 121 into linear motion to drive the front wheels of the electric vehicle.

[0065] During the steering process of the electric vehicle 100, the steering controller 122 receives a steering angle signal from the vehicle controller 130 and receives a steering angle signal from the power battery 140 (eg, Figure 1 The steering motor 121 outputs torque according to the steering angle indicated by the steering angle signal.

[0066] Similarly, the torque output by the steering motor 121 includes forward torque and reverse torque. When the steering motor 121 outputs forward torque and reverse torque, the steering directions of the front wheels of the electric vehicle 100 are opposite.

[0067] The rear-wheel steering system 110, the front-wheel steering system 120, and the vehicle controller 130 are communicatively connected, and the embodiments of the present application do not limit the specific communication connection method. For example, the steering controller 112 in the rear-wheel steering system 110 and the vehicle controller 130 can communicate via a private CAN network, and the steering controller 122 in the front-wheel steering system 120 and the vehicle controller 130 can communicate via a public CAN network. For another example, the vehicle controller 130 can communicate with the steering controller 112 and the steering controller 122 via the same CAN network.

[0068] See also Figure 3 , Figure 3A schematic diagram of a steering system is shown. The steering system 20 includes a steering motor 201, a steering controller 202, a steering gear 203, and a housing 204. The steering motor 201 is connected to the steering controller 202 and the steering gear 203. The steering motor 201 and the steering controller 202 can be integrated into one body. The steering gear 203 is connected to at least one wheel of the electric vehicle.

[0069] The steering gear 203 includes a deceleration assembly 2031 and a tie rod 2032 .

[0070] The reduction assembly 2031 is connected to the steering motor shaft of the steering motor 201 and the tie rod 2032, and is used to convert the high speed and low torque of the steering motor 201 into low speed and high torque suitable for steering, and transmit it to the tie rod 2032. The reduction assembly 2031 is such as a worm gear, gears, belts, etc.

[0071] The tie rod 2032 is used to respond to the output of the deceleration assembly 2031 and move in the axial direction to drive the wheels of the electric vehicle to turn. The two ends of the tie rod 2032 are connected to the wheels of the electric vehicle through connectors. The connectors can be ball joints, steering knuckles, etc.

[0072] The housing 204 is sleeved on the tie rod 2032 , and both ends of the tie rod 2032 are outside the housing 204 . The cross-sectional areas of the two ends of the tie rod 2032 are larger than the cross-sectional area of ​​the middle position of the tie rod 2032 .

[0073] In the case where the tie rod 2032 moves over the stroke, the two ends of the tie rod 2032 collide with the ends of the housing 204, and the torque output by the steering motor 201 cannot drive the tie rod to continue moving, causing the steering motor to stall and the weak parts of the steering system (such as belts) to be damaged. Figure 4 , Figure 4 A schematic diagram showing the collision between the left end of a tie rod and a housing is shown. Figure 4 In the housing 204, the tie rod 2032 moves to the right, causing the left end of the tie rod to collide with the housing.

[0074] In one embodiment, Figure 3 The steering system 20 shown can be a front wheel steering system. In another embodiment, the steering system 20 can also be a rear wheel steering system.

[0075] The above describes the structure of the embodiment of the present application. The following describes the steering system stall protection method provided by the present application in conjunction with specific embodiments. The steering system stall protection method provided by the present application includes the following steps.

[0076] After a first moment t1 when the tie rod starts to move to one side and before a second moment t2 when the tie rod moves to one side to a preset position, the steering motor is controlled to output a first torque and to have a rotational speed greater than a preset rotational speed.

[0077] The preset position refers to the farthest position that the tie rod can move within the stroke.

[0078] In one embodiment, the tie rod moves to one side to the preset position, and the end point of the tie rod on that side moves to the preset position. For example, the tie rod moves to the right side until the right end of the tie rod moves to the preset position.

[0079] In one embodiment, the tie rod starts to move to one side, which may refer to the tie rod starting to move to one side from an initial position, where the initial position refers to the position of the center of the tie rod when the wheel connected to the tie rod is not turning, that is, the zero position of the tie rod, or it may refer to any position of the tie rod between the initial position and the preset position.

[0080] For easier understanding, see Figure 5 、 Figure 6 and Figure 7 , Figure 5 A schematic diagram showing the maximum movable range of a tie rod is shown. Figure 6 A schematic diagram showing the moving position of a tie rod is shown. Figure 7 A schematic diagram of the timing relationship of a first torque is shown.

[0081] like Figure 5 As shown, Figure 5 (a) shows a schematic diagram of a tie rod moving to the left until the right end of the tie rod collides with the housing. Figure 5 (b) in the figure shows a schematic diagram of a situation where the tie rod moves to the right and the left end of the tie rod collides with the housing.

[0082] exist Figure 5 In the figure, the L section is the maximum range in which the tie rod can move, that is, the maximum range in which the tie rod can move.

[0083] exist Figure 6 In the figure, point A is the farthest position that the left end of the tie rod can move, point B is the farthest position that the right end of the tie rod can move, points A1 and B1 are preset positions, the L1 segment between points A1 and B1 is the stroke of the tie rod, and the L2 segment between points A and A1 and the L2 segment between points B and B1 are the ranges within which the tie rod can move after overstroke.

[0084] In one embodiment, the preset position may also be any position in the L2 segment, that is, any position between the farthest position that the tie rod can move within the stroke and the farthest position that the tie rod can move (that is, the mechanical limit).

[0085] exist Figure 7 In the embodiment, between the first moment t1 and the second moment t2, the tie rod moves to one end within the L1 section, the steering motor outputs the first torque, and the rotation speed of the steering motor is greater than the preset rotation speed w.

[0086] Between the first moment t1 and the second moment t2 , the steering motor is controlled to output a first torque and the rotational speed of the steering motor is controlled to be greater than a preset rotational speed, thereby controlling the movement of the tie rod.

[0087] The first torque may be a positive torque or a negative torque, and the direction of the first torque is determined by the direction in which the tie rod moves or the direction in which the wheel turns.

[0088] In one embodiment, the protection method further includes: after the first moment t1 and before the second moment t2, first controlling the rotation speed of the steering motor to increase from zero, and then controlling the rotation speed of the steering motor to decrease.

[0089] The steering motor rotates to drive the tie rod to move, and the change in the moving speed of the tie rod is consistent with the change in the speed of the steering motor.

[0090] In one embodiment, the first torque output by the steering motor may be controlled to first increase and then decrease, thereby controlling the rotational speed of the steering motor to increase from zero and then decrease.

[0091] In another embodiment, the steering motor may be controlled to first output a first torque and then output a torque in a direction opposite to the first torque, thereby controlling the rotational speed of the steering motor to increase from zero and then decrease.

[0092] For easier understanding, see Figure 8 , Figure 8 A schematic diagram of the timing relationship of the moving speed of a tie rod is shown, taking the tie rod moving to the right as an example.

[0093] Between the first moment t1 and the second moment t2, when the tie rod moves to the right until one end of the tie rod is within the L1 segment, the moving speed of the tie rod first increases and then decreases.

[0094] In this embodiment, the steering motor is first controlled to increase its rotational speed from zero to control the driving tie rod to start moving to one side, and then the steering motor is controlled to decrease its rotational speed to control the tie rod to reduce its movement speed before moving to one side to a preset position. This makes the movement speed of the tie rod smaller when approaching the preset position, making it easier to subsequently control the tie rod to stop moving.

[0095] In one embodiment, the protection method further includes: after the first moment t1 and before the second moment t2, first controlling the speed of the steering motor to increase from zero, then controlling the speed of the steering motor to remain unchanged, and finally controlling the speed of the steering motor to decrease.

[0096] The fluctuation of the rotation speed of the steering motor within the moving range can also be regarded as the rotation speed of the steering motor remaining unchanged.

[0097] In one embodiment, the protection method further includes: controlling the rotation speed of the steering motor to decrease to zero at or before the second moment t2.

[0098] At the second moment t2, if the steering motor is still rotating, it means that the tie rod is still moving to one side, and the tie rod is bound to move over the stroke, further increasing the risk of collision between one end of the tie rod and the housing.

[0099] Continue to see Figure 8 At the second moment t2, the right end of the tie rod is located at point B1, and the speed of the tie rod movement is reduced to zero.

[0100] In one embodiment, the steering motor may be controlled to reduce the output first torque, thereby controlling the rotational speed of the steering motor to be reduced to zero at or before the second moment.

[0101] In another embodiment, the steering motor may be controlled to output a torque in a direction opposite to the first torque, thereby controlling the rotational speed of the steering motor to be reduced to zero at or before the second moment.

[0102] In this embodiment, the steering motor speed is controlled to be reduced to zero before the tie rod moves to the preset position, so that the tie rod is controlled to stop moving before the tie rod moves to the preset position, thereby avoiding overstroke of the tie rod and causing the steering motor to stall.

[0103] In one case, if the rotation speed of the steering motor cannot be reduced to zero at or before the second moment, the tie rod will overstroke, and there is a high risk of collision between one end of the tie rod and one end of the housing.

[0104] Thus, in one embodiment, the protection method further includes: after the second moment t2, when it is detected that the first torque output by the steering motor is greater than the preset torque and the speed of the steering motor is less than or equal to the preset speed, controlling the steering motor to reduce the output first torque.

[0105] Among them, the preset torque is a larger value, the preset speed is a smaller value, the first torque output by the steering motor is greater than the preset torque and the speed of the steering motor is less than or equal to the preset speed, that is, when the torque output by the steering motor is large, the speed of the steering motor is small, indicating that the steering motor is about to stall or has stalled.

[0106] If the first torque output by the steering motor is greater than the preset torque and the steering motor speed is less than or equal to the preset speed, it also indicates that the tie rod has overstroked or one end of the tie rod has collided with the housing. If the tie rod has overstroked, the steering motor is close to stalling. If the tie rod has collided with the housing, the steering motor is stalled.

[0107] In this case, by controlling the steering motor to reduce the output first torque, the steering motor is avoided or alleviated from stalling, thereby solving the problems caused by stalling, such as a sharp increase in the current of the steering motor, a rapid increase in the temperature of the steering motor, and damage to the mechanical structure.

[0108] Continue to see Figure 7 After the second moment t2, one end of the tie rod is in the L2 segment, the first torque is greater than the preset torque T, the speed of the steering motor is less than the preset speed w, and the first torque decreases.

[0109] In this embodiment, while the steering motor drives the tie rod to steer the wheels of the electric vehicle, the tie rod is driven to one side and to a preset position by controlling the steering motor to output a first torque and maintaining the steering motor speed above a preset speed. Subsequently, by detecting that the first torque output by the steering motor is greater than the preset torque and the steering motor speed is less than or equal to the preset speed, overstroke of the tie rod or collision of one end of the tie rod with the housing is detected. In this case, the steering motor is controlled to reduce the first torque output to alleviate or prevent steering motor stall. This, in turn, addresses issues such as a sharp increase in steering motor current, a rapid increase in steering motor temperature, and mechanical damage caused by stalling, thereby protecting the steering system.

[0110] In one embodiment, the protection method further includes: after the second moment t2, when it is detected that the rate of change of the current of the steering motor is greater than a preset current rate of change, controlling the steering motor to reduce the output first torque.

[0111] The rate of change of the steering motor current can indicate whether the steering motor is stalled or nearly stalled. A rate of change of the steering motor current greater than a preset rate of change, i.e., a sudden increase in the steering motor current, indicates that the steering motor is stalled or nearly stalled.

[0112] In one embodiment, the rate of change of the bus current of the steering controller can also reflect whether the steering motor is stalled or close to stalling.

[0113] In this embodiment, a steering motor stall or near stall is detected by detecting that the rate of change of the steering motor current is greater than a preset current rate of change. In this case, the steering motor is controlled to reduce the first torque output, thereby alleviating or preventing the steering motor stall and protecting the steering system.

[0114] In one embodiment, the protection method further includes: after the second time t2, when it is detected that the temperature change rate of the steering motor is greater than a preset temperature change rate, controlling the steering motor to reduce the output first torque.

[0115] The rate of change of the steering motor temperature can indicate whether the steering motor is stalled or near stalling. If the rate of change of the steering motor temperature is greater than a preset temperature change rate, i.e., a sudden increase in the steering motor temperature, the steering motor is stalled or near stalling.

[0116] In this embodiment, a steering motor stall or near stall is detected by detecting that the rate of change in the steering motor temperature exceeds a preset temperature change rate. In this case, the steering motor is controlled to reduce the first torque output, thereby alleviating or preventing the stall and simultaneously reducing the temperature of the steering system, thereby protecting the steering system.

[0117] In one embodiment, the protection method further includes: after the second moment t2, when it is detected that the first torque output by the steering motor is greater than the preset torque and the rotation speed of the steering motor is zero, controlling the steering motor to stop outputting the first torque.

[0118] The first torque output by the steering motor is greater than the preset torque and the speed of the steering motor is zero, that is, the steering motor does not rotate when the torque output by the steering motor is large, indicating that the steering motor is blocked.

[0119] In this case, by controlling the steering motor to stop outputting the first torque, the steering motor is prevented from being continuously stalled, and the problems caused by the stall, such as a sharp increase in the current of the steering motor, a rapid increase in the temperature of the steering motor, and damage to the mechanical structure, are solved.

[0120] For easier understanding, see Figure 9 , Figure 9 Another schematic diagram of the timing relationship of the first torque is shown.

[0121] exist Figure 9 In the embodiment, between the first moment t1 and the second moment t2, the steering motor outputs the first torque, and the speed of the steering motor is greater than the preset speed w; after the second moment t2, the first torque is greater than the preset torque T, the speed of the steering motor is 0, and the output of the first torque is stopped.

[0122] In one embodiment, the power supply of the steering motor may be cut off to control the steering motor to stop outputting the first torque.

[0123] In another embodiment, the steering motor may be controlled to stop outputting the first torque by locking the output shaft of the steering motor through a mechanical device.

[0124] In this embodiment, automatic detection of a steering motor stall is achieved by detecting that the first torque output by the steering motor is greater than a preset torque and the steering motor speed is zero. In this case, the steering motor is controlled to stop outputting the first torque, preventing the steering motor from being continuously stalled. This addresses issues such as a sharp increase in steering motor current, a rapid increase in steering motor temperature, and mechanical damage caused by a stall, thereby protecting the steering system.

[0125] In one embodiment, the protection method further includes: after the second moment t2, when it is detected that the current change rate of the steering motor is greater than a preset current change rate and the speed of the steering motor is zero, controlling the steering motor to stop outputting the first torque.

[0126] In one embodiment, the protection method further includes: after the second time t2, when it is detected that the temperature change rate of the steering motor is greater than a preset temperature change rate and the speed of the steering motor is zero, controlling the steering motor to stop outputting the first torque.

[0127] In an embodiment of the present application, automatic detection of steering motor stalling can be achieved by detecting whether the rate of change of the steering motor current is greater than a preset current rate of change and the steering motor speed is zero, or whether the rate of change of the steering motor temperature is greater than a preset temperature rate of change and the steering motor speed is zero. This is achieved by controlling the steering motor to stop outputting the first torque, thereby preventing the steering motor from being continuously stalled. This addresses issues such as a sharp increase in steering motor current, a rapid increase in steering motor temperature, and damage to the mechanical structure caused by stalling, thereby protecting the steering system.

[0128] In one embodiment, the protection method further includes: after the second moment t2, when it is detected that the first torque output by the steering motor is greater than the preset torque and the speed of the steering motor is less than or equal to the preset speed, controlling the steering motor to output a second torque in the opposite direction to the first torque.

[0129] The first torque output by the steering motor is greater than the preset torque and the rotation speed of the steering motor is less than or equal to the preset rotation speed, indicating that the tie rod has overstroked or one end of the tie rod has collided with the housing.

[0130] In this case, by controlling the steering electrical output to produce a second torque in the opposite direction of the first torque, the tie rod is controlled to move to the other side, thereby avoiding collision of one end of the tie rod with the housing, or alleviating steering motor stalling caused by collision of one end of the tie rod with the housing.

[0131] For easier understanding, see Figure 10 , Figure 10A timing diagram of the torque output by a steering motor is shown.

[0132] exist Figure 10 In the embodiment, between the first moment t1 and the second moment t2, the steering motor outputs the first torque, and the speed of the steering motor is greater than the preset speed w; after the second moment t2, the first torque is greater than the preset torque T, the speed of the steering motor is less than the preset speed w, the first torque is stopped from being output, and the second torque is output.

[0133] In this embodiment, detection of tie rod overstroke or collision with the housing is achieved by detecting whether the first torque output by the steering motor is greater than a preset torque and the steering motor speed is less than or equal to a preset speed. In this case, the steering motor is controlled to output a second torque in the opposite direction of the first torque to control the tie rod to move to the other side, thereby preventing one end of the tie rod from colliding with the housing or alleviating steering motor stall caused by collision, thereby protecting the steering system.

[0134] The specific control process of the first torque or the second torque output by the steering motor will be described in detail below.

[0135] In one embodiment, the protection method specifically includes: after the second moment t2, the smaller the rotation speed of the steering motor is, the larger the reduced first torque output by the steering motor is controlled.

[0136] After the second moment t2 , when the first torque is greater than the preset torque, the smaller the rotation speed of the steering motor is, the closer the steering motor is to a stalled state or the more serious the stall is.

[0137] In this embodiment, the smaller the speed of the steering motor, the larger the first torque after the reduction output of the steering motor is controlled to be, so that the first torque after the reduction output of the steering motor can be flexibly controlled according to the speed of the steering motor, and the steering motor can be alleviated or avoided from being blocked under different speeds of the steering motor, thereby protecting the steering system.

[0138] In one embodiment, the protection method specifically includes: after the second moment t2, the greater the change rate of the detected current of the steering motor or the change rate of the temperature of the steering motor, the smaller the first torque after the reduction output by the steering motor is controlled.

[0139] After the second time t2 , when the change rate of the current of the steering motor is greater than the current change rate, a greater change rate of the current of the steering motor indicates that the steering motor is closer to a stalled state or the stall is more serious.

[0140] When the rate of change of the temperature of the steering motor is greater than the temperature change rate, a greater rate of change of the temperature of the steering motor indicates that the steering motor is closer to a stalled state or the stall is more serious.

[0141] In this embodiment, the greater the rate of change of the current of the steering motor or the rate of change of the temperature of the steering motor, the smaller the first torque after the reduction output of the steering motor is controlled, so that the first torque after the reduction output of the steering motor can be flexibly controlled according to the rate of change of the current of the steering motor or the rate of change of the temperature of the steering motor, so that the steering motor can be alleviated or avoided from stalling under different conditions of the rate of change of the current or the rate of change of the temperature, thereby protecting the steering system.

[0142] In one embodiment, the protection method specifically includes: after the second moment t2, the smaller the detected rotation speed of the steering motor is, the larger the second torque output by the steering motor is controlled.

[0143] After the second moment t2 , when the first torque is greater than the preset torque, the smaller the rotation speed of the steering motor is, the closer the steering motor is to a stalled state or the more serious the stall is.

[0144] In this embodiment, the smaller the speed of the steering motor, the larger the second torque output by the steering motor is controlled to be, thereby realizing flexible control of the second torque output by the steering motor according to the speed of the steering motor, and realizing that when the speed of the steering motor is different, the tie rod can be driven to move to the other side, thereby alleviating or avoiding steering motor jamming and protecting the steering system.

[0145] In one embodiment, the protection method specifically includes: after the second moment t2, the greater the detected change rate of the current of the steering motor or the change rate of the temperature of the steering motor, the greater the second torque output by the steering motor is controlled.

[0146] After the second time t2 , when the change rate of the current of the steering motor is greater than the current change rate, a greater change rate of the current of the steering motor indicates that the steering motor is closer to a stalled state or the stall is more serious.

[0147] When the rate of change of the temperature of the steering motor is greater than the temperature change rate, a greater rate of change of the temperature of the steering motor indicates that the steering motor is closer to a stalled state or the stall is more serious.

[0148] In this embodiment, the greater the rate of change of the current of the steering motor or the rate of change of the temperature of the steering motor, the greater the second torque output by the steering motor is controlled, so that the second torque output by the steering motor can be flexibly controlled according to the rate of change of the current of the steering motor or the rate of change of the temperature of the steering motor, and the tie rod can be driven to move to the other side under different conditions of the rate of change of the current or the rate of change of the temperature, thereby alleviating or avoiding the jam of the steering motor and protecting the steering system.

[0149] The following will describe in detail a method for determining the moving position of the tie rod during its movement.

[0150] In one embodiment, the protection method specifically includes: receiving a displacement signal from a displacement sensor, and obtaining a displacement indicated by the displacement signal as the displacement of the tie rod.

[0151] Among them, the displacement sensor is used to directly measure the displacement of the tie rod and output a displacement signal.

[0152] In one embodiment, a contact corresponding to the displacement sensor is provided inside the tie rod, which may be a metal sheet. The displacement indicated by the displacement signal detected by the displacement sensor is the displacement of the contact, ie, the displacement of the tie rod.

[0153] In this embodiment, by directly using the displacement indicated by the displacement signal from the displacement sensor as the displacement of the tie rod, the displacement of the tie rod can be quickly acquired, which is beneficial for subsequently determining the displacement of the tie rod based on the displacement of the tie rod to control the steering motor.

[0154] However, the range of the displacement sensor is fixed, which makes it difficult to support the demand for detecting larger displacements, and its detection error will increase with the increase of displacement.

[0155] Thus, in one embodiment, the protection method specifically includes: calculating the displacement of the tie rod according to the steering motor speed indicated by the speed signal of the steering motor.

[0156] It can be known that the steering motor outputs torque to drive the tie rod to move.

[0157] In one embodiment, after the steering motor speed of the steering motor is acquired, the displacement of the tie rod is calculated according to the steering motor speed of the steering motor, the transmission ratio of the reduction assembly, and the lead of the tie rod.

[0158] In this embodiment, by detecting the speed signal of the steering motor and calculating the displacement of the tie rod according to the steering motor speed indicated by the speed signal, the displacement of the tie rod is accurately obtained, which is conducive to subsequently determining the displacement of the tie rod based on the displacement of the tie rod to accurately control the steering motor.

[0159] In another embodiment of the present application, a steering system is further provided. The steering system includes a steering motor, a tie rod and a steering controller. The steering motor is used to drive the tie rod to move to drive the wheels of the electric vehicle to steer.

[0160] Steering controllers are used to:

[0161] After a first moment when the tie rod starts to move to one side and before a second moment when the tie rod moves to one side to a preset position, controlling the steering motor to output a first torque and controlling the speed of the steering motor to be greater than a preset speed;

[0162] After the second moment, when it is detected that the first torque output by the steering motor is greater than the preset torque and the rotation speed of the steering motor is less than or equal to the preset rotation speed, the steering motor is controlled to reduce the output first torque.

[0163] In this embodiment, while the steering motor drives the tie rod to steer the wheels of the electric vehicle, the steering controller drives the tie rod to one side and to a preset position by controlling the steering motor to output a first torque and maintain a rotational speed greater than a preset speed. The steering controller then detects tie rod overstroke or collision between one end of the tie rod and the housing by detecting that the first torque output by the steering motor is greater than the preset torque and the rotational speed of the steering motor is less than or equal to the preset speed. In this case, the steering controller controls the steering motor to reduce the first torque output, thereby alleviating or preventing steering motor stall. This resolves issues such as a sharp increase in steering motor current, a rapid increase in steering motor temperature, and mechanical damage caused by stalling, thereby protecting the steering system.

[0164] In one embodiment, the steering controller is further configured to: after the second moment, when it is detected that the first torque output by the steering motor is greater than the preset torque and the rotation speed of the steering motor is zero, control the steering motor to stop outputting the first torque.

[0165] In this embodiment, the steering controller automatically detects that the steering motor has stalled by detecting that the first torque output by the steering motor is greater than a preset torque and that the steering motor speed is zero. In this case, the steering controller controls the steering motor to stop outputting the first torque, preventing the steering motor from being continuously stalled. This addresses issues such as a sharp increase in steering motor current, a rapid increase in steering motor temperature, and mechanical damage caused by stalling, thereby protecting the steering system.

[0166] In one embodiment, the steering system further includes a displacement sensor disposed on the tie rod, and the steering controller 202 is further configured to receive a displacement signal from the displacement sensor and obtain the displacement indicated by the displacement signal as the displacement of the tie rod.

[0167] In this embodiment, by directly using the displacement indicated by the displacement signal from the displacement sensor as the displacement of the tie rod, the displacement of the tie rod can be quickly acquired, which is beneficial for subsequently determining the displacement of the tie rod based on the displacement of the tie rod to control the steering motor.

[0168] However, the range of the displacement sensor is fixed, which makes it difficult to support the demand for detecting larger displacements, and its detection error will increase with the increase of displacement.

[0169] Thus, in one embodiment, the steering controller is further configured to calculate the displacement of the tie rod according to the steering motor speed indicated by the speed signal of the steering motor.

[0170] In this embodiment, by detecting the speed signal of the steering motor and calculating the displacement of the tie rod according to the steering motor speed indicated by the speed signal, the displacement of the tie rod is accurately obtained, which is conducive to subsequently determining the displacement of the tie rod based on the displacement of the tie rod to accurately control the steering motor.

[0171] For easier understanding, see Figure 11 , Figure 11 A schematic diagram of a steering controller is shown.

[0172] exist Figure 11 In the embodiment of the present invention, the steering controller receives the displacement signal sent by the displacement sensor and / or detects the speed signal of the steering motor, calculates the displacement of the tie rod according to the displacement signal or the speed signal, thereby determining the position of the tie rod, and then controls the steering motor to adjust the output torque.

[0173] It can be understood that all relevant contents of each step involved in the above-mentioned embodiment of the steering controller can be referred to the embodiment of the electric vehicle, and the embodiment of the present application will not be repeated here.

[0174] In another embodiment of the present application, an electric vehicle is provided. The electric vehicle includes a steering system, the steering system including a steering motor, a tie rod, and a steering controller. The steering motor is used to drive the tie rod to move and drive the wheels of the electric vehicle to steer. The steering controller is used to:

[0175] After a first moment when the tie rod starts to move to one side and before a second moment when the tie rod moves to one side to a preset position, controlling the steering motor to output a first torque and controlling the speed of the steering motor to be greater than a preset speed;

[0176] After the second moment, when it is detected that the first torque output by the steering motor is greater than the preset torque and the rotation speed of the steering motor is less than or equal to the preset rotation speed, the steering motor is controlled to reduce the output first torque.

[0177] In this embodiment, while the steering motor drives the tie rod to steer the wheels of the electric vehicle, the steering controller drives the tie rod to one side and to a preset position by controlling the steering motor to output a first torque and maintain a rotational speed greater than a preset speed. The steering controller then detects tie rod overstroke or collision between one end of the tie rod and the housing by detecting that the first torque output by the steering motor is greater than the preset torque and the rotational speed of the steering motor is less than or equal to the preset speed. In this case, the steering controller controls the steering motor to reduce the first torque output, thereby alleviating or preventing steering motor stall. This resolves issues such as a sharp increase in steering motor current, a rapid increase in steering motor temperature, and mechanical damage caused by stalling, thereby protecting the steering system.

[0178] In one embodiment, the steering controller is further configured to: after the second moment, when it is detected that the first torque output by the steering motor is greater than the preset torque and the rotation speed of the steering motor is zero, control the steering motor to stop outputting the first torque.

[0179] In this embodiment, the steering controller automatically detects that the steering motor has stalled by detecting that the first torque output by the steering motor is greater than a preset torque and that the steering motor speed is zero. In this case, the steering controller controls the steering motor to stop outputting the first torque, preventing the steering motor from being continuously stalled. This addresses issues such as a sharp increase in steering motor current, a rapid increase in steering motor temperature, and mechanical damage caused by stalling, thereby protecting the steering system.

[0180] It can be understood that all relevant contents of each step involved in the above-mentioned embodiment of the steering controller can be referred to the embodiment of the control method, and the embodiment of the present application will not be repeated here.

[0181] Finally, it should be noted that the above are only specific embodiments of this application, but the scope of protection of this application is not limited to them. Any changes or substitutions within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A method for protecting a steering system from stall, characterized in that: The protection method is used to adjust the torque output by the steering motor to protect the steering system when the steering motor of the steering system drives the tie rod to move and drives the wheels of the electric vehicle to turn. The protection method includes: After a first moment when the tie rod starts to move to one side and before a second moment when the tie rod moves to one side to a preset position, controlling the steering motor to output a first torque and controlling the speed of the steering motor to be greater than a preset speed; After the second moment, when it is detected that the first torque output by the steering motor is greater than the preset torque and the rotation speed of the steering motor is less than or equal to the preset rotation speed, the steering motor is controlled to reduce the output first torque.

2. The protection method according to claim 1, characterized in that: The protection method further comprises: After the second moment, when it is detected that the first torque output by the steering motor is greater than the preset torque and the rotation speed of the steering motor is zero, the steering motor is controlled to stop outputting the first torque.

3. The protection method according to claim 1, characterized in that: The protection method further comprises: After the second moment, when it is detected that the first torque output by the steering motor is greater than the preset torque and the speed of the steering motor is less than or equal to the preset speed, the steering motor is controlled to output a second torque in a direction opposite to the first torque.

4. The protection method according to claim 1, characterized in that: The protection method further comprises: After the second moment, when it is detected that the rate of change of the current of the steering motor is greater than a preset rate of change of the current, the steering motor is controlled to reduce the output first torque.

5. The protection method according to claim 1, characterized in that: The protection method further comprises: After the second moment, when it is detected that the temperature change rate of the steering motor is greater than a preset temperature change rate, the steering motor is controlled to reduce the output first torque.

6. The protection method according to claim 1, characterized in that: The protection method further comprises: After the first moment and before the second moment, the rotational speed of the steering motor is first controlled to increase from zero, and then the rotational speed of the steering motor is controlled to decrease.

7. The protection method according to claim 6, characterized in that: The protection method specifically includes: The rotation speed of the steering motor is controlled to decrease to zero at or before the second moment.

8. The protection method according to claim 1, characterized in that: The protection method specifically includes: After the second moment, the smaller the rotation speed of the steering motor is, the larger the first torque after reduction output by the steering motor is controlled.

9. The protection method according to claim 1, characterized in that: The protection method specifically includes: After the second moment, the greater the detected rate of change of the current of the steering motor or the greater the detected rate of change of the temperature of the steering motor, the smaller the first torque after reduction output by the steering motor is controlled.

10. The protection method according to claim 3, characterized in that: The protection method specifically includes: After the second moment, the smaller the detected rotation speed of the steering motor is, the larger the second torque output by the steering motor is controlled.

11. The protection method according to claim 3, characterized in that: The protection method specifically includes: After the second moment, the greater the detected rate of change of the current of the steering motor or the rate of change of the temperature of the steering motor is, the greater the second torque output by the steering motor is controlled.

12. A steering system, characterized in that: The steering system includes a steering motor, a tie rod, and a steering controller. The steering motor is used to drive the tie rod to move and drive the wheels of the electric vehicle to steer. The steering controller is used to: After a first moment when the tie rod starts to move to one side and before a second moment when the tie rod moves to one side to a preset position, controlling the steering motor to output a first torque and controlling the speed of the steering motor to be greater than a preset speed; After the second moment, when it is detected that the first torque output by the steering motor is greater than the preset torque and the rotation speed of the steering motor is less than or equal to the preset rotation speed, the steering motor is controlled to reduce the output first torque.

13. The steering system according to claim 12, characterized in that The steering controller is also used for: After the second moment, when it is detected that the first torque output by the steering motor is greater than the preset torque and the rotation speed of the steering motor is zero, the steering motor is controlled to stop outputting the first torque.

14. An electric vehicle, characterized in that: The electric vehicle includes a steering system, which includes a steering motor, a tie rod, and a steering controller. The steering motor is used to drive the tie rod to move and drive the wheels of the electric vehicle to steer. The steering controller is used to: After a first moment when the tie rod starts to move to one side and before a second moment when the tie rod moves to one side to a preset position, controlling the steering motor to output a first torque and controlling the speed of the steering motor to be greater than a preset speed; After the second moment, when it is detected that the first torque output by the steering motor is greater than the preset torque and the rotation speed of the steering motor is less than or equal to the preset rotation speed, the steering motor is controlled to reduce the output first torque.

15. The electric vehicle according to claim 12, characterized in that The steering controller is also used for: After the second moment, when it is detected that the first torque output by the steering motor is greater than the preset torque and the rotation speed of the steering motor is zero, the steering motor is controlled to stop outputting the first torque.

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