Displacement detection device, system and method

Abstract

The present application provides a displacement detection device, system and method, which relate to the technical field of wire-controlled steering. The displacement detection device includes an induction block arranged on a ball screw of a wire-controlled steering system; a plurality of induction coils within a set range of the distance induction block, the induction block moves axially along the ball screw driven by the ball screw, the plurality of induction coils transmit detected electrical signals to corresponding sensor chips, and the sensor chip converts the electrical signals into displacement signals; displacement detection of different precisions and ranges is achieved by induction coils of different lengths, so that the combination of coils of different lengths can simultaneously meet the requirements of large range and high precision.

Description

Technical Field

[0001] The present application relates to the technical field of wire-controlled steering, and in particular to a displacement detection device, system and method. Background Art

[0002] In the wire control steering system, the driver's operation is converted into an electrical signal through the sensor. After the signal is analyzed and processed, it is directly transmitted to the actuator through the wire. In the actuator, the displacement of the ball screw needs to be converted into axial rotation by gears to detect the lateral displacement of the ball screw. This has the following problems:

[0003] 1) It is necessary to add a set of mechanical structure for position detection to the system, which increases the cost; 2) The position information of axial detection is affected by many factors, such as the error caused by the gap between the ball screw thread and the meshing gear, which causes the current steering position information deviation, or the signal error caused by the demagnetization of the electric angle sensor, which directly affects the steering position information, and then affects the driving accuracy and precision; 3) With the development of society, the demand for high performance and safety of automobiles is gradually increasing, requiring the steering system displacement detection mechanism to have a large range, high accuracy, save automobile space and redundant control, etc. The current steering system cannot meet these requirements.

[0004] In view of this, this application is hereby filed. Summary of the invention

[0005] One object of the present application is to provide a displacement detection device, system and method, which can realize displacement detection with different accuracy and range through induction coils of different lengths, have a simple mechanical structure, and meet the requirements of range and accuracy at the same time.

[0006] To achieve the above objectives, some embodiments of the present application provide the following aspects:

[0007] In a first aspect, the present application provides a displacement detection device, comprising:

[0008] A sensing block disposed on the ball screw of the steer-by-wire system;

[0009] A plurality of induction coils within a set range from the induction block, the lengths of the plurality of induction coils are not completely the same;

[0010] A sensor chip electrically connected to each of the induction coils;

[0011] Driven by the ball screw, the sensing block moves axially along the ball screw, and the multiple induction coils transmit the detected electrical signals to the corresponding sensor chips, and the sensor chips convert the electrical signals into displacement signals; wherein, the accuracy of the displacement signal detected by the longer induction coil is higher than the accuracy of the displacement signal detected by the shorter induction coil, and the range of the displacement signal detected by the longer induction coil is greater than the range of the displacement signal detected by the shorter induction coil.

[0012] Optionally, the plurality of induction coils include at least two first induction coils and at least two second induction coils;

[0013] The length of the first induction coil is greater than that of the second induction coil;

[0014] The plurality of induction coils are stacked within a set range of the induction block.

[0015] Optionally, a plurality of induction coils are stacked on a multi-layer circuit board and are centrally symmetrically distributed;

[0016] The induction block is axially symmetrical with the plurality of induction coils.

[0017] Optionally, at least two first induction coils are redundant with each other, and at least two second induction coils are redundant with each other;

[0018] A first induction coil and a second induction coil form a coil group, which are powered by a power supply;

[0019] Different coil groups have different power supplies.

[0020] In a second aspect, the present application provides a displacement detection method, which is applicable to the displacement detection device provided in any embodiment, and the method includes:

[0021] collecting displacement signals detected by a plurality of induction coils;

[0022] A displacement signal of corresponding accuracy and range is selected for processing to generate a displacement vector signal; the displacement vector signal is used for vehicle steering control.

[0023] Optionally, the selecting a displacement signal of corresponding accuracy and range for processing according to the current wheel angle includes:

[0024] If the current wheel angle is greater than the set threshold, a low-precision and large-range displacement signal is selected for processing;

[0025] If the current wheel angle is less than or equal to the set threshold, a high-precision and small-range displacement signal is selected for processing.

[0026] Optionally, the low-precision and large-range displacement signal is selected when determining the vehicle's rotation direction or estimating the steering angle;

[0027] The high-precision and small-range displacement signal is selected when accurately calculating the steering angle.

[0028] Optionally, the current wheel angle is acquired by a wheel angle sensor or a steering wheel angle sensor.

[0029] Optionally, before selecting a displacement signal with corresponding accuracy and range for processing according to the current wheel angle, the method further includes:

[0030] If the displacement signal is not collected or exceeds the set range, it is determined that the induction coil is faulty;

[0031] If there is a fault, a normal induction coil is switched to, wherein the normal induction coil includes a coil belonging to the same group as the faulty induction coil or at least one induction coil belonging to a different group from the faulty induction coil.

[0032] In a third aspect, some embodiments of the present application further provide a displacement detection system, including: the displacement detection device provided by any embodiment;

[0033] A controller connected to the displacement detection device, wherein the controller is used to execute the displacement detection method described in any embodiment.

[0034] Compared with the prior art, the present application adopts a linear detection method of an induction coil, which is structurally different from the rotary type on the market and spatially eliminates the position detection machinery in the traditional wire-controlled steering system. The present application has a simple structure and saves space in the vehicle. The present application realizes displacement detection of different accuracies and ranges through induction coils of different lengths, so that the combination of coils of different lengths can simultaneously meet the requirements of large range and high precision.

[0035] Furthermore, in the present application, at least two first induction coils are redundant with each other, and at least two second induction coils are redundant with each other, and are respectively powered by different independent power supplies. When one induction coil fails, it can switch to another coil group without causing much impact on vehicle control, thereby greatly increasing driving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic diagram of the structure of a displacement detection device provided in an embodiment of the present application;

[0037] Figure 2 A schematic diagram of a circuit board and a sensor block provided in an embodiment of the present application;

[0038] Figure 3 A flow chart of a displacement detection method provided in an embodiment of the present application;

[0039] Figure 4A circuit diagram of a displacement detection system provided in an embodiment of the present application;

[0040] Among them, 10, displacement detection device, 11, induction block, 12, induction coil, 121, first induction coil, 122, second induction coil, 13, sensor chip, 14, circuit board, 15, power supply, 20, controller. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0042] Embodiment 1

[0043] The present application provides a displacement detection device 10, which is applied to an actuator in a steer-by-wire system, namely a ball screw 1, to detect the lateral displacement of the ball screw 1. Figure 1 The displacement detection device 10 includes a sensing block 11 , a plurality of sensing coils 12 and a sensor chip 13 .

[0044] The induction block 11 causes the magnetic field of the induction coil 12 to change, and can be a metal block. The induction block 11 is arranged on the ball screw 1, and is preferably fixed at the center.

[0045] Each induction coil 12 is composed of a transmitting coil and two receiving coils. The transmitting coil and the capacitor form an LC oscillator, which is directly driven by the chip. It generates a magnetic field in the transmitting coil area, which is picked up by the receiving coil. The distance between the multiple induction coils 12 and the induction block 11 is within a set range so that the movement of the induction block 11 can be sensed. The set range can be calibrated through experiments.

[0046] Optionally, the lengths of the multiple induction coils 12 are not completely the same, and the multiple induction coils 12 include at least two first induction coils 121 and at least two second induction coils 122; the length of the first induction coil 121 is greater than the length of the second induction coil 122. The lengths of at least two first induction coils 121 are the same, and the lengths of at least two second induction coils 122 are the same. The multiple induction coils 12 are stacked within the set range of the induction block. Figure 2, multiple induction coils 12 are stacked on a multi-layer circuit board (e.g., a 4-layer PCB board) 14, and one induction coil 12 is arranged on one layer of the circuit board 14. The stacking order of the two first induction coils 121 and the two second induction coils 122 is not limited. In order to ensure that the distance between the induction coils 12 and the induction block 11 is the same, the multiple induction coils 12 are distributed in a central symmetrical manner, and the induction block 11 and the multiple induction coils 12 are axially symmetrical, and the symmetry axis is the center line connecting the circuit board 14 and the induction block 11, see Figure 2 The bold vertical line in .

[0047] Each induction coil 12 is electrically connected to a sensor chip 13. The induction block 11 moves axially along the ball screw 1 under the drive of the ball screw 1. The voltage generated by the receiver coil depends on the position of the target metal block, because the area shielded by the target generates a weaker secondary voltage than the area not shielded by the target. The multiple induction coils 12 transmit the detected electrical signals to the corresponding sensor chips 13, and the sensor chips 13 convert the electrical signals into displacement signals; wherein, the accuracy of the displacement signal detected by the longer induction coil 12 is higher than that of the shorter induction coil 12, and the range of the displacement signal detected by the longer induction coil 12 is greater than that of the shorter induction coil 12.

[0048] It should be noted that the present application only limits the lengths of the multiple induction coils 12 to different lengths, but the specific length needs to be determined according to the moving distance of the ball screw 1 and is obtained through experimental calibration. The present application does not limit the specific length value.

[0049] The present application adopts a linear detection method of the induction coil 12, which is different from the rotary type on the market in structure. It saves the position detection machinery in the traditional wire-controlled steering system in space. The present application has a simple structure and saves space in the vehicle. The present application realizes displacement detection of different precisions and ranges through induction coils 12 of different lengths, so that the combination of coils 12 of different lengths can meet the requirements of large range and high precision at the same time. The combination of long and short coils 12 not only meets the range requirements of steering, but also transmits the relative position of the ball screw 1 with higher precision to the controller 20, so as to achieve the purpose of precise control.

[0050] Preferably, see Figure 1 At least two first induction coils 121 are mutually redundant, at least two second induction coils 122 are mutually redundant, one first induction coil 121 and one second induction coil 122 form a coil group, which is powered by one power supply 15; different coil groups have different power supplies 15. Different power supplies 15 can be used to switch power supplies when the induction coil 12 fails, thereby achieving power supply 15 redundancy and induction coil 12 redundancy.

[0051] Embodiment 2

[0052] The present application provides a displacement detection method, which is applicable to the displacement detection device 10 in the first embodiment and is specifically executed by a controller 20 connected to the displacement detection device 10 .

[0053] See also Figure 3 , the displacement detection method comprises the following steps:

[0054] S110 , collecting displacement signals detected by a plurality of induction coils 12 .

[0055] S120, selecting a displacement signal of corresponding accuracy and range for processing to generate a displacement vector signal; the displacement vector signal is used for vehicle steering control.

[0056] The controller 20 collects displacement signals transmitted by the multiple sensor chips 13 in real time, including high-precision short-range displacement signals and low-precision long-range displacement signals.

[0057] Optionally, one method of S120 is to select a suitable displacement signal according to the wheel angle. The current wheel angle is obtained by a wheel angle sensor or a steering wheel angle sensor. If the current wheel angle is greater than a set threshold, such as driving conditions such as steering and U-turns, a low-precision and large-range displacement signal (i.e., the signal generated by a long coil) is selected for processing, and there is no need to process a high-precision and small-range displacement signal (i.e., the signal generated by a short coil); if the current wheel angle is less than or equal to the set threshold, such as when driving in a straight line, a high-precision and small-range displacement signal (i.e., the signal generated by a short coil) is selected for processing, and there is no need to process a signal generated by a long coil. The set threshold can be selected based on experiments, for example, 10 degrees.

[0058] Another way of S120 is to select a suitable displacement signal according to the accuracy requirement. When determining the direction of vehicle rotation or estimating the steering angle, select the displacement signal with low precision and large range; when accurately calculating the steering angle, select the displacement signal with high precision and small range. Specifically, only the signal generated by the long coil is needed when the vehicle is turning normally. When the vehicle performs the lane keeping function, the bumpy road surface may cause the steering wheel to move abnormally. It is necessary to judge the steering wheel angle in time. The signal generated by the long coil is needed to judge the direction of rotation and estimate the steering angle. At the same time, the signal generated by the short coil is needed to accurately calculate the steering angle for adjustment to ensure the normal driving of the vehicle. There is no need to process the signal generated by the long coil.

[0059] The processing method is: select the initial displacement and the latest displacement from the real-time displacement signal, calculate the stroke and displacement direction, and transmit the stroke, displacement direction and time information to the electric power steering system.

[0060] Optionally, before selecting a displacement signal of corresponding accuracy and range for processing according to the current wheel angle, it is determined whether the induction coil 12 is faulty according to the displacement signal. For example, if the displacement signal is not collected or exceeds a set range, it is determined that the induction coil 12 is faulty. If it is faulty, switch to a normal induction coil. The normal induction coil includes a coil belonging to the same group as the faulty induction coil or at least one induction coil belonging to a different group from the faulty induction coil.

[0061] For example, if a coil in the first induction coil 121 fails, the signal of the failed coil 12 is no longer collected, but the signal of another induction coil in the same group as the failed coil 12 is collected.

[0062] For example, if all coils in the first induction coil 121 group are faulty, the signal of the faulty coil 12 and the signal of the coil group to which it belongs will no longer be collected, but will be switched to another normal coil group. In another normal coil group, you can switch to any induction coil 12, or all induction coils 12, as long as they can meet the current accuracy requirements. Among them, the set range is determined according to the maximum range of the induction coil 12. This embodiment uses fault judgment and in-group / out-group coil switching to make the same group of induction coils redundant, and different groups of induction coils are also redundant, which greatly ensures driving safety.

[0063] The method provided in this embodiment meets the current requirements of displacement detection, which are large range, high precision, saving automobile space, control redundancy, power supply redundancy and high safety.

[0064] Embodiment 3

[0065] This embodiment provides a displacement detection system. Figure 4 , including: the displacement detection device 10 in the first embodiment, and a controller 20 connected to the displacement detection device 10. The function of the controller 20 is described in the second embodiment and will not be repeated here.

[0066] The displacement detection device 10 and the controller 20 may be connected linearly or wirelessly, and the present application does not limit the specific connection method.

[0067] The flow chart or block diagram in the accompanying drawings shows the possible architecture, function and operation of the equipment, method and computer program product according to various embodiments of the present application. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some implementations as replacements, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated system for hardware that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0068] It is obvious to those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and that the present application can be implemented in other specific forms without departing from the spirit or basic features of the present application. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present application is limited by the attached claims rather than the above description, so it is intended to include all changes that fall within the meaning and scope of the equivalent elements of the claims in the present application. Any figure mark in the claims should not be regarded as limiting the claims involved. In addition, it is obvious that the word "comprising" does not exclude other units or steps, and the singular does not exclude the plural. Multiple units or devices stated in the device claim can also be implemented by one unit or device through software or hardware. The words first, second, etc. are used to indicate names, and do not indicate any particular order.

Claims

1. A displacement detection device, characterized in that: include: A sensing block disposed on the ball screw of the steer-by-wire system; A plurality of induction coils within a set range from the induction block, the lengths of the plurality of induction coils are not completely the same; A sensor chip electrically connected to each of the induction coils; The induction block moves axially along the ball screw under the drive of the ball screw, and the multiple induction coils transmit the detected electrical signals to the corresponding sensor chips, and the sensor chips convert the electrical signals into displacement signals; wherein the accuracy of the displacement signal detected by the longer induction coil is lower than the accuracy of the displacement signal detected by the shorter induction coil, and the range of the displacement signal detected by the longer induction coil is greater than the range of the displacement signal detected by the shorter induction coil; The plurality of induction coils include at least two first induction coils and at least two second induction coils; The length of the first induction coil is greater than that of the second induction coil; The at least two first induction coils are redundant with each other, the at least two second induction coils are redundant with each other, and one of the first induction coils and one of the second induction coils form a coil group; If the displacement signal is not collected or exceeds the set range, it is determined that the corresponding induction coil is faulty. If faulty, it is switched to a normal induction coil, where the normal induction coil includes a coil belonging to the same group as the faulty induction coil or at least one induction coil belonging to a different group from the faulty induction coil. Through fault judgment and switching of coils inside / outside the group, the induction coils in the same group are redundant with each other, and the induction coils in different groups are also redundant with each other.

2. The displacement detection device according to claim 1, characterized in that: The plurality of induction coils are stacked within a set range of the induction block.

3. The displacement detection device according to claim 2, characterized in that: Multiple induction coils are stacked on a multi-layer circuit board and distributed symmetrically in the center; The induction block is axially symmetrical with the plurality of induction coils.

4. The displacement detection device according to claim 1, characterized in that: A coil group is powered by a power supply; Different coil groups have different power supplies.

5. A displacement detection method, characterized in that: Applicable to the displacement detection device according to any one of claims 1 to 4, the method comprising: collecting displacement signals detected by a plurality of induction coils; Selecting a displacement signal of corresponding accuracy and range for processing to generate a displacement vector signal; the displacement vector signal is used for vehicle steering control; The selecting of displacement signals of corresponding accuracy and range for processing comprises: If the current wheel angle is greater than the set threshold, a low-precision and large-range displacement signal is selected for processing; If the current wheel angle is less than or equal to the set threshold, a high-precision and small-range displacement signal is selected for processing; Before selecting a displacement signal with corresponding accuracy and range for processing according to the current wheel angle, the method further includes: If the displacement signal is not collected or exceeds the set range, it is determined that the corresponding induction coil is faulty; If a fault occurs, switching to a normal induction coil, wherein the normal induction coil includes a coil belonging to the same group as the faulty induction coil or at least one induction coil belonging to a different group from the faulty induction coil; Through fault judgment and switching of coils inside / outside the group, the induction coils in the same group are redundant with each other, and the induction coils in different groups are also redundant with each other.

6. The displacement detection method according to claim 5, characterized in that: The current wheel angle is obtained through a wheel angle sensor or a steering wheel angle sensor.

7. A displacement detection system, characterized in that: include: The displacement detection device according to any one of claims 1 to 4; A controller connected to the displacement detection device, wherein the controller is used to execute the displacement detection method according to any one of claims 5 to 6.

Images