Backhaul difference compensation system, method and device, head-up display device and storage medium

Abstract

The invention provides a backhaul difference compensation system, method and device, a head-up display device and a storage medium, and belongs to the technical field of HUD display control, and the backhaul difference compensation system comprises a stepping motor which is configured to drive a movable assembly of an HUD to move; the measuring unit is configured to perform state switching under the pushing of the movable assembly; the controller is configured to count the actual movement step number of the stepping motor in the process that the movable assembly pushes the measuring unit to be switched from the first state to the second state, and signals corresponding to the first state and the second state are opposite; and based on the actual motion step number and the theoretical motion step number, the return stroke difference of the stepping motor is determined, and the theoretical motion step number is the theoretical demand step number of the stepping motor when the measuring unit is switched from the first state to the second state. According to the embodiment of the invention, the backhaul difference can be dynamically calibrated in each power-on or specific period of the HUD, and the positioning precision is improved.

Description

Technical Field

[0001] This disclosure relates to the field of HUD display control technology, and in particular to a backflip compensation system, method, apparatus, head-up display device, and storage medium. Background Technology

[0002] Head-up displays (HUDs) are widely used in modern vehicles. They project driving information such as vehicle speed and navigation onto the windshield or a dedicated imaging panel in front of the driver using optical reflection principles to improve driving safety. HUDs typically use stepper motors to drive a large reflector to rotate, thereby adjusting the display height of the virtual image to accommodate drivers of different heights.

[0003] A stepper motor is an actuator that converts electrical pulse signals into angular or linear displacement. Ideally, the number of steps the motor takes is proportional to the distance a reflector moves. However, when power is transmitted through mechanical transmission mechanisms such as gears and worm gears, a certain clearance must be maintained between the gears to prevent mechanical jamming, accommodate lubricating oil, and compensate for thermal expansion and contraction. This clearance is called backlash, tooth clearance, or idle distance in mechanical engineering.

[0004] When the stepper motor switches from one direction of rotation to the opposite direction, although the motor shaft starts to rotate, it must first complete this backlash before the output shaft (large reflector) begins to move in the opposite direction. This lost travel during which the motor rotates but the load does not move will cause inaccurate positioning of the HUD virtual image adjustment. Users will feel obvious lag or dead zones when adjusting, which seriously affects the user experience.

[0005] Therefore, how to provide a technical solution that can detect and compensate for the backlash difference of stepper motors in real time and dynamically is a technical problem that urgently needs to be solved. Summary of the Invention

[0006] This disclosure provides a backlash compensation system, method, apparatus, head-up display device, and storage medium, aiming to solve the problem that fixed backlash compensation cannot adapt to mechanical wear and environmental changes, resulting in inaccurate HUD positioning.

[0007] The technical solution disclosed herein is implemented as follows: In a first aspect, this disclosure provides a backlash compensation system for use in a HUD device. The backlash compensation system includes: a stepper motor configured to drive the movement of an active component of the HUD; a measurement unit configured to switch states under the influence of the active component; a controller configured to count the actual number of steps the stepper motor moves during the process of the active component driving the measurement unit to switch from a first state to a second state, wherein the signals corresponding to the first state and the second state are opposite; and to determine the backlash of the stepper motor based on the actual number of steps and the theoretical number of steps, wherein the theoretical number of steps is the theoretically required number of steps for the stepper motor to switch from the first state to the second state.

[0008] Secondly, this disclosure provides a backhaul error compensation method, which includes: The actual number of steps and the theoretical number of steps of the stepper motor are obtained. The actual number of steps is the actual number of steps taken by the stepper motor to drive the active component of the HUD to switch the measurement unit from the first state to the second state. The theoretical number of steps is the theoretical number of steps required by the stepper motor when the measurement unit switches from the first state to the second state. The signals corresponding to the first state and the second state are opposite. Based on the actual number of steps and the theoretical number of steps, the backlash difference of the stepper motor is determined.

[0009] Thirdly, this disclosure provides a backlash compensation device, which includes: an acquisition part and a determination part; the acquisition part is configured to acquire the actual number of steps and the theoretical number of steps of the stepper motor, wherein the actual number of steps is the actual number of steps taken by the stepper motor driving the active component of the HUD to switch the measurement unit from a first state to a second state, and the theoretical number of steps is the theoretical number of steps required by the stepper motor when the measurement unit switches from the first state to the second state, and the signals corresponding to the first state and the second state are opposite; the determination part is configured to determine the backlash of the stepper motor based on the actual number of steps and the theoretical number of steps.

[0010] Fourthly, this disclosure provides a head-up display device, which includes a controller and a display unit; wherein the controller is configured to, in response to a received reverse adjustment command, drive the stepper motor of the display unit to run a number of steps corresponding to the backlash difference, and then drive the stepper motor to run a number of steps corresponding to the reverse adjustment command; the display unit is configured to, based on the controller's drive, rotate the stepper motor to drive a movable component to adjust the angle to obtain an adjusted image display height; and display an image at the adjusted image display height position on the windshield.

[0011] Fifthly, this disclosure provides a computer-readable storage medium storing at least one instruction, which is executed by a processor to perform the function of a controller in the backhaul compensation system as described in the first aspect.

[0012] In a sixth aspect, this disclosure provides a vehicle that includes the head-up display device described in the fourth aspect.

[0013] This disclosure provides a backflip compensation system that dynamically calibrates the backflip at each power-on or during a specific cycle, thereby measuring the actual number of steps the stepper motor moves in real time. Since the actual number of steps includes the actual idle steps under the current wear condition, the backflip determined by the difference between the actual and theoretical steps can automatically adapt to wear changes, improving positioning accuracy. Furthermore, this embodiment allows each HUD, and even the same HUD, to have different backflips at different times, which reduces the precision requirements for gear manufacturing and thus lowers production difficulty. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the components of the HUD provided in this disclosure.

[0015] Figure 2 This is a schematic diagram of the composition of a backflip compensation system provided in this disclosure.

[0016] Figure 3 This is a flowchart illustrating the process for determining the return distance provided in this disclosure.

[0017] Figure 4 This is a schematic diagram of the signal changes corresponding to the microswitch provided in this disclosure.

[0018] Figure 5 This is a schematic diagram illustrating the principle of hysteresis calculation provided in this disclosure.

[0019] Figure 6 This is a flowchart illustrating the movement step count based on the ambient temperature correction theory provided in this disclosure.

[0020] Figure 7 This is a flowchart illustrating the logical verification of the return difference provided in this disclosure.

[0021] Figure 8 This is a schematic diagram of the composition of a backflip compensation device provided in this disclosure. Detailed Implementation

[0022] The technical solutions in this disclosure will now be clearly and completely described with reference to the accompanying drawings.

[0023] like Figure 1As shown, the vehicle is equipped with a HUD 100, which includes a controller 101 and a display unit 102. The controller 101 is used to determine (e.g., calculate) the type, size, shape, color, and display brightness of the HUD image displayed by the display unit 102 based on a display control strategy. The controller 101 is also used to control a stepper motor to drive the moving components to rotate based on control commands.

[0024] The display unit 102 contains a precision optomechanical structure for adjusting the position of the virtual image (such as height or distance adjustment). The core drive source of this mechanism is a stepper motor, and the driven object is a moving component, such as a large reflecting mirror or an aspherical mirror. To achieve closed-loop control or position calibration, the HUD 100 is also equipped with a measurement unit, such as a microswitch.

[0025] The display unit 102 projects an image onto the windshield 103 to form a virtual image 104 that can be observed by the driver's vision. The visual effect presented by the virtual image 104 is that the virtual image 104 is projected onto a projection surface 105 at a set distance in front of the vehicle, but the real environment remains visible through the projection surface 105.

[0026] During projection, the HUD 100 needs to project an image precisely onto a specific area of ​​the windshield 103. However, the drive chain between the stepper motor and the moving components typically includes a reduction gearbox. To prevent gear jamming and to accommodate grease, a certain clearance must be maintained between the gears. When the stepper motor reverses direction, it must first idle through this clearance before the output shaft follows. This idle stroke is called the backlash.

[0027] The presence of backlash can cause a backlash phenomenon in stepper motors when changing their rotation direction. This means that the stepper motor rotor has already rotated, but the output shaft (such as a reflector) has not yet responded, resulting in the actual position lagging behind the commanded position. This lag directly affects the adjustment accuracy of the virtual image 104, causing image jitter or positioning deviation, which seriously affects the user experience.

[0028] In related technologies, static fixed compensation is typically used. This involves measuring the backlash difference of each HUD 100 unit on the production line before it leaves the factory and embedding this value in the controller 101. However, as the HUD 100 operates for an extended period, gear wear causes the backlash to gradually increase, rendering the factory-set fixed compensation value inaccurate. Furthermore, static fixed compensation relies on production line consistency, but assembly stress and batch material variations can lead to individual differences, resulting in low accuracy of the uniform backlash difference.

[0029] Based on the above problems, this disclosure aims to provide a hysteresis compensation system capable of dynamically calibrating the hysteresis during HUD startup or operation. For example... Figure 2As shown, the backlash compensation system includes: a controller 101, a stepper motor 201, and a measurement unit 202.

[0030] like Figure 3 As shown, controller 101 is configured to perform the following steps S301 and S302.

[0031] In step S301, the actual number of steps the stepper motor moves during the process of the active component pushing the measurement unit from the first state to the second state is counted.

[0032] In step S302, the backlash difference of the stepper motor is determined based on the actual number of steps and the theoretical number of steps.

[0033] The signals corresponding to the first state are opposite to those corresponding to the second state.

[0034] The controller 101 is responsible for sending pulse signals to drive the stepper motor 201 to rotate, and at the same time, it monitors the level signal changes of the measurement unit 202 in real time through the general-purpose input / output interface.

[0035] Stepper motor 201 is an actuator that converts electrical pulse signals into angular displacement. Stepper motor 201 has a fixed step angle, for example, 1.8 degrees / step. Under open-loop control, the motor rotor rotates by one step angle for each pulse sent by controller 101. However, due to the backlash, the rotation of the rotor is not always equivalent to the displacement of the load (moving component 203).

[0036] In this embodiment, the stepper motor 201 is connected to the movable component 203 via a transmission mechanism to drive the movable component 203 to move. To convert the high-speed, low-torque output of the stepper motor 201 into the low-speed, high-torque required for the adjustment of the movable component 203 and to achieve self-locking, the transmission mechanism can employ a worm gear driven worm wheel structure. A gap must exist at the meshing point between the worm gear connecting the stepper motor 201 shaft and the worm wheel connecting the movable component 203 shaft to prevent jamming due to thermal expansion and to accommodate lubricating grease. When the stepper motor 201 switches from clockwise to counterclockwise rotation, the worm gear must first pass through this gap before the worm wheel begins to move in the opposite direction. This invalid stroke is the backlash difference that this disclosure needs to compensate for.

[0037] During movement, the movable component 203 pushes the measuring unit 202, causing a change in the state of the measuring unit 202. The measuring unit 202 is a sensor used to detect the position state of the movable component 203. In this embodiment, the measuring unit 202 specifically refers to a position switch with hysteresis characteristics, which can be a micro switch. Compared to absolute encoders or resolvers, micro switches are low-cost, and their signal output is a simple switching quantity, either high or low level. The controller 101 only needs to read it through the input / output interface, without the need for complex decoding algorithms or ADC conversion, resulting in lower computing power requirements and hardware costs. Furthermore, the micro switch is usually directly triggered by the movable component 203, rather than being mounted on the motor shaft, allowing direct detection of the physical position of the final optical element.

[0038] The first state is the physical state in which the measuring unit 202 is triggered, pressed, or activated by the active component 203. This corresponds to the state in which the push rod of the measuring unit 202 is pressed down beyond the operating position (OP), and can be referred to as the compression state. In this state, the measuring unit 202 outputs an on signal, such as a logic low level.

[0039] The second state is the physical state of the measurement unit 202 being reset, released, or not triggered. This corresponds to the state where the push rod of the measurement unit 202 rebounds beyond the release point (Open Contact Point, OC), and can be recorded as the release state. In this state, the measurement unit 202 outputs a disconnect signal, such as a logic high level.

[0040] Since the signals corresponding to the first state and the second state are opposite, the controller 101 can accurately capture the moment of state switching by detecting the level transition (e.g., from 0 to 1, or from 1 to 0).

[0041] The active component 203 refers to the part of HUD 100 that is physically moved by the stepper motor 201, such as the mirror bracket or the mirror itself. Figure 2 The diagram shows that the movable component 203 can rotate around a solid dot, adjusting the height or imaging distance of the virtual image 104 by changing the angle. Driven by the stepper motor 201, the movable component 203 can move in two directions: pressing against the measuring unit 202 and moving away from the measuring unit 202.

[0042] The theoretical number of motion steps refers to the number of motor steps required for the measuring unit 202 to completely transition from a compressed state to a released state in an ideal, rigid system with no backlash and no wear. This value is a fixed constant calculated based on the differential travel length of the microswitch and the transmission ratio of the transmission mechanism. The transmission ratio refers to the linear displacement at the push rod corresponding to each rotation of the stepper motor 201. For example, the microswitch specification states that the differential travel length is 0.5 mm. If the transmission mechanism is designed so that the stepper motor 201 rotates in 10 steps, and the circumference of the gear is 0.1 mm, then the transmission ratio is 0.1 / 10 = 0.01, meaning that the linear displacement corresponding to one step of the stepper motor 201 is 0.01 mm. Therefore, the theoretical number of motion steps X1 = 0.5 / 0.01 = 50 steps. This value is usually pre-stored in the memory of the controller 101.

[0043] The actual number of motion steps refers to the total number of pulse steps emitted by the stepper motor 201 from the moment it receives the on signal until it receives the off signal, as measured and recorded by the controller 101 during a specific reverse calibration process. The actual number of motion steps includes the number of idle steps to overcome the backlash difference plus the effective displacement steps that push the micro switch to rebound.

[0044] Specifically, the determination of the hysteresis includes the following stages, which will be explained using the measurement unit 202 as a micro switch as an example.

[0045] When the HUD 100 is started or enters calibration mode, the controller 101 first performs a zeroing operation. The controller 101 sends pulses to the stepper motor 201, driving it to rotate in a first direction. The stepper motor 201, through a worm gear mechanism, drives the movable component 203 to gradually approach and press against the push rod of the micro switch. The controller 101 monitors the signal of the micro switch in real time. When the push rod of the micro switch is pressed down to OP, the internal contacts of the switch close, the signal changes from an open signal to an on signal, and the micro switch is in the first state. For example, as shown... Figure 4 The diagram shows the signal change corresponding to the micro switch. The signal monitored by the controller 101 changes from high level to low level. The falling edge indicated by the solid arrow in the diagram indicates that the micro switch is at the OP point.

[0046] The controller 101 detects the instant of the signal transition ( Figure 4 Upon the falling edge of the signal, the stepper motor 201 is immediately stopped from being driven, and the current logic position of the stepper motor 201 is marked as zero or the current timestamp is recorded. At this time, the microswitch is in a physically compressed state, and because it is a unidirectional continuous compression, the meshing surfaces of the gears are in close contact, and the positive clearance is zero.

[0047] Reverse start and counting phase. To measure the hysteresis, the direction of motion must be changed. Controller 101 controls stepper motor 201 to start rotating in a second direction opposite to the first direction. At the same time, controller 101 starts its internal high-speed counter to count the number of pulses sent to stepper motor 201.

[0048] During the reverse rotation of the stepper motor 201, the physical system undergoes two consecutive but distinctly different phases, which together constitute the actual number of steps.

[0049] Phase 1: The first stroke component corresponding to the idle stroke elimination begins to rotate in reverse, driving the worm gear to rotate in reverse as well. Due to the gear meshing gap (i.e., backlash difference) between the worm gear and the worm wheel, in the initial stage of reversal, the worm gear teeth move within the gap and have not yet contacted the other side of the worm wheel teeth. Therefore, the worm wheel and the moving component 203 remain stationary, and the microswitch push rod remains pressed in the OP position, maintaining the ON signal. The number of steps the motor takes in this phase is entirely used to compensate for the gap; this idle step count is the backlash difference obtained in this embodiment.

[0050] Phase Two: The second stroke component corresponding to the effective displacement steps. When the backlash is completely eliminated, the worm gear teeth re-mesh with the worm wheel teeth. Stepper motor 201 continues to rotate, beginning to physically move the movable component 203 via the worm wheel, gradually moving away from the microswitch. The microswitch's push rod then begins to rebound. The process of the push rod rebounding from OP to OC corresponds to the differential stroke of the microswitch. The number of steps taken by stepper motor 201 in this phase is converted into the actual displacement of the push rod, theoretically equal to the theoretical number of steps x 1.

[0051] Signal capture and data acquisition phase. During the reversal process, controller 101 continuously polls the microswitch signal. When the movable component 203 moves a sufficient distance, causing the push rod to rebound to OC, the microswitch contacts reset and open. The signal changes from an on signal to an off signal, and the microswitch enters the second state. To improve detection accuracy during this process, stepper motor 201 rotates at a low speed to enhance the detection accuracy of the off signal transition. (Reference) Figure 4 The controller 101 detects a signal transition from low to high level; the rising edge indicated by the dashed arrow in the diagram represents the microswitch being at open (OC). The controller 101 captures this transition signal. Figure 4 Upon the rising edge of the counter, step counting immediately stops. The value in the counter at this time is the actual number of steps X2. The backlash calculation stage begins. Since X2 = idle steps + effective displacement steps, and the effective displacement steps equal the theoretical number of steps X1, X2 - X1 = idle steps, i.e., backlash = X2 - X1. This eliminates the travel steps of the microswitch itself, separating the steps purely caused by mechanical backlash. The controller 101 stores the calculated backlash in its memory.

[0052] like Figure 5 The diagram illustrates the principle of backflip calculation. Point P1 represents the maximum reachable position of the active component 203, and point P2 represents the current position of the active component 203. During the zero-point determination phase, the active component 203 moves from point P2 to point OP, then reverses direction to reach point OC. The number of steps counted by the controller 101 corresponds to the first stroke component of the dashed double arrow and the second stroke component of the solid double arrow, i.e., X2 corresponds to the actual number of steps. The dashed first stroke component indicates that the stepper motor 201 has rotated, but the position of the active component 203 has not changed. The distance X1 between OP and OC corresponds to the theoretical number of steps.

[0053] During subsequent normal display control (e.g., when the driver adjusts the HUD height), whenever the controller 101 receives a reversing command from the stepper motor 201, such as changing from "adjust up" to "adjust down", the controller 101 reads the stored backlash difference. Before executing the displacement command, a compensation command of one backlash difference pulse is sent to the stepper motor 201. The backlash difference pulse drives the stepper motor 201 to idle and pass through the gap, ensuring that each subsequent displacement step can be transmitted to the moving component 203 in real time and accurately, thereby achieving precise adjustment of the virtual image position.

[0054] This embodiment dynamically calibrates the backlash difference at each power-on or specific cycle, thereby measuring the actual number of steps the stepper motor 201 moves in real time. Since the actual number of steps includes the actual idle steps under the current wear condition, the backlash difference determined by the difference between the actual and theoretical steps can automatically adapt to wear changes, improving positioning accuracy. Furthermore, this embodiment allows each HUD, and even the same HUD, to have different backlash differences at different times, which reduces the precision requirements for gear manufacturing and thus lowers production difficulty.

[0055] Because the precision transmission mechanism inside the HUD 100 is typically made of different materials—for example, worm gears often use engineering plastics like polyoxymethylene to reduce noise, while the motor shaft and base may be made of metal—the thermal expansion coefficients of these different materials differ significantly. With changes in ambient temperature, the gear geometry, center distance, and microswitch trigger stroke all undergo minute physical deformations. These minute deformations are amplified in precision optical systems, causing the fixed theoretical number of motion steps to become inaccurate at extreme temperatures, thus affecting the accuracy of the backflip calculation. Therefore, in this embodiment of the disclosure, as... Figure 6 As shown, the controller 101 is also configured to perform the following steps S601 and S602.

[0056] In step S601, based on the current ambient temperature and according to the preset temperature drift coefficient model, the basic theoretical number of steps is corrected to obtain the theoretical number of steps.

[0057] In step S602, the backlash error of the stepper motor is determined based on the difference between the actual number of steps and the theoretical number of steps.

[0058] The current ambient temperature refers to the real-time physical temperature inside the HUD 100 or near the stepper motor 201, used to assess the degree of thermal expansion and contraction of materials. It can be obtained from a negative temperature coefficient thermistor integrated on the control board of the HUD 100, a temperature sensor inside the motor driver chip, or an external ambient temperature signal sent from the vehicle bus.

[0059] The temperature drift coefficient model is a mathematical model or data mapping table pre-stored in the memory of the controller 101, used to describe the correspondence between changes in ambient temperature and changes in the theoretical number of movement steps. The temperature drift coefficient model can be established during the product development phase by testing the HUD assembly in a high and low temperature environment test chamber. For example, at multiple temperature points such as -40℃, 25℃, and 85℃, the actual number of physical steps required for the microswitch to transition from a compressed state to a released state is measured and fitted into a curve. For example, the obtained temperature drift coefficient model can be a linear function k=1+α×(T-25), where α is the comprehensive thermal expansion coefficient, such as 0.96, or it can be a piecewise correction table, such as k=1.02 when T<0°; and k=0.98 when T>60°.

[0060] The theoretical number of motion steps refers to the number of theoretical motion steps that the controller 101 should be able to perform under the current ambient temperature after weighting or compensating the factory-preset basic theoretical motion steps using the current temperature drift coefficient model. The theoretical number of motion steps represents the actual physical travel steps that the stepper motor 201 should travel from point OP to point OC under the current ambient temperature, without considering backlash.

[0061] For example, when the HUD 100 is powered on or the calibration program is started, the controller 101 first reads the basic theoretical number of motion steps from the memory. This value corresponds to the theoretical number of motion steps X1' of the stepper motor 201 corresponding to the differential travel of the microswitch at a standard room temperature of 25°C. Simultaneously, the controller 101 reads the current ambient temperature as T=65°C via the temperature sensor interface. Because the plastic gear expands at high temperatures, causing the gear pitch circle diameter to increase, the actual travel of the microswitch in terms of motor steps will be shorter (because the motor can push the same linear distance with a smaller rotation angle). The temperature drift coefficient model at 65°C has k=0.98. If the temperature drift coefficient model is X1=X1'×k, then X1=100×0.98=98.

[0062] The transmission mechanism of the HUD 100 typically uses gears made of high-molecular materials such as polyoxymethylene (POM). Its coefficient of linear expansion is much higher than that of metal shafts or aluminum alloy housings. At extreme temperatures (such as 85°C), the plastic gears expand, resulting in a smaller tooth backlash and altering the microscopic manifestation of the transmission ratio (change in effective radius) and the position of the microswitch contacts. If the controller 101 still uses the theoretical number of steps at room temperature as a benchmark, the change in stroke caused by thermal expansion will be incorrectly included in the hysteresis error. This calculation error will cause the hysteresis compensation value to deviate from the true value. For example, a calculated value that is too small will result in insufficient compensation during motor commutation, causing lag in screen movement; a calculated value that is too large will result in overcompensation, causing screen jumps or motor overshoot.

[0063] In this embodiment, a temperature drift coefficient model is introduced to construct a theoretical number of motion steps that vary with temperature. Therefore, whether it is a cold start in winter or after exposure to the sun in summer, the controller can obtain an accurate number of idling steps for compensation, ensuring that the HUD virtual image can respond accurately and smoothly to the driver's adjustment commands under any climatic conditions, eliminating nonlinear positioning errors caused by temperature.

[0064] In some embodiments, after calculating the return distance difference, it is not applied directly, but first undergoes a logical verification process to ensure that the value is physically reasonable. Specifically, such as... Figure 7 As shown, controller 101 is configured to perform the following steps S701 to S703.

[0065] In step S701, it is determined whether the homing difference is within a preset valid range.

[0066] If yes, proceed to step S702; otherwise, proceed to step S703.

[0067] In step S702, the return difference is stored in the memory.

[0068] In step S703, a fault warning signal is generated and the calibration operation of the stepper motor is stopped.

[0069] The preset effective range refers to a pre-stored numerical interval [Vmin, Vmax] used to define reasonable and possible backlash differences. This effective range is based on a comprehensive setting of the mechanical design tolerances of the HUD transmission mechanism, gear module, maximum allowable wear, and microswitch travel tolerance. The lower limit Vmin can be set to 0 or a very small positive integer (e.g., 2 steps), because physically, gear clearance cannot be negative; if the calculated value is less than 0, it usually means that the microswitch signal is jittering or triggering too early. The upper limit Vmax is set according to the maximum wear limit of the gear. For example, if the design of a brand-new gear clearance corresponds to 10 steps, and the clearance is allowed to increase to 50 steps after wear, if the calculated value reaches 200 steps, it means that the motor has been idling for too long before the switch resets, which is physically impossible and highly likely indicates a mechanical failure (such as broken teeth, disengaged transmission chain) or switch malfunction.

[0070] The fault warning signal is a status signal generated by the controller 101 to identify system abnormalities when the hysteresis error exceeds the aforementioned effective range. This signal can be an error flag bit in the controller 101's internal register or a diagnostic fault code sent to the vehicle's instrument panel or infotainment system via the vehicle communication bus. It is used to notify the upper-level system HUD 100 that it is in an unhealthy state and trigger corresponding degradation or shutdown protection strategies.

[0071] Controller 101 executes protective actions based on the specific circumstances of the over-limit situation. An excessively large hysteresis indicates that the stepper motor 201 traveled a long distance after reversing before the microswitch signal changed, or there was no change at all. Possible faults include microswitch contacts sticking (unable to disconnect), gear breakage causing the motor to idle and unable to drive the load, or a severely loose transmission mechanism. A fault warning signal can be generated indicating mechanical transmission failure or switch sticking.

[0072] A small or negative return error indicates that the actual number of steps is less than the theoretical number. Possible faults include fatigue of the internal spring of the microswitch leading to minimal return hysteresis, electromagnetic interference causing false trigger pulses on the signal line, or abnormal material shrinkage due to extremely low temperatures. A fault warning signal indicating sensor signal abnormality can be generated.

[0073] Stopping the calibration action of stepper motor 201 means that controller 101 immediately interrupts the current pulse output, keeping stepper motor 201 stationary and locking the current phase sequence, and no longer continuing to execute the adjustment action of subsequent active components 203. This prevents forced movement under fault conditions from causing mechanical structure jamming, motor overheating, or writing incorrect parameters to permanent memory. Controller 101 can use the previous valid backflip difference (or factory default value) as a temporary parameter, or directly disable the adjustment function of HUD 100 to prevent the user from forcibly adjusting under fault conditions, causing the virtual image 104 to deviate from the field of view.

[0074] This embodiment introduces a numerical validity verification mechanism to prevent secondary damage caused by erroneous compensation. For example, if the microswitch inside the HUD malfunctions and remains in a normally closed state (contact sticking), the stepper motor 201 will reverse, but the controller 101 will continuously detect the on signal. The stepper motor 201 may continue to rotate until it hits the mechanical hard limit, at which point the controller records a large number of actual steps. Without verification, the controller 101 will incorrectly assume a large backlash. In subsequent normal display control, when the driver requests a downward adjustment of one step, the controller 101 will first perform a large compensation, causing the reflector to deflect dramatically momentarily. This disclosure, for backlashes deviating from the effective range, prevents the controller 101 from updating the compensation parameters, stops the motor, and reports a fault, limiting the fault to the level of switch failure and avoiding physical damage to the mechanical structure caused by blind algorithm execution.

[0075] Based on the same concept as the backflip compensation system described above, this disclosure aims to provide a backflip compensation method. The controller 101 in any of the backflip compensation system embodiments described above is used to execute the backflip compensation method. To avoid repetition, it will not be described again here.

[0076] like Figure 8 As shown, this disclosure also provides a backlash compensation device, which includes: an acquisition section 801 and a determination section 802; the acquisition section 801 is configured to acquire the actual number of movement steps and the theoretical number of movement steps of the stepper motor, wherein the actual number of movement steps is the actual number of steps taken by the stepper motor to drive the active component of the HUD to move to the measurement unit switching from a first state to a second state, and the theoretical number of movement steps is the theoretical number of steps required for the measurement unit to switch from the first state to the second state, wherein the signals corresponding to the first state and the second state are opposite; the determination section 802 is configured to determine the backlash of the stepper motor based on the actual number of movement steps and the theoretical number of movement steps.

[0077] In some embodiments, the actual number of steps is the number of steps the stepper motor moves between the controller receiving an on signal when the measuring unit is in the first state and receiving an off signal when the measuring unit is in the second state.

[0078] In some embodiments, the backlash compensation device further includes a control section configured to control the stepper motor to drive the movable component to move in a first direction; and, when receiving an on signal indicating that the measuring unit is in a compressed state, to control the stepper motor to drive the movable component to move in a second direction opposite to the first direction, and to count the number of steps of the stepper motor until receiving an off signal indicating that the measuring unit is in a released state, to obtain the actual number of steps moved.

[0079] In some embodiments, the theoretical number of steps is determined based on the differential travel length of the measuring unit and the transmission ratio of the stepper motor driving the active component.

[0080] In some embodiments, the measuring unit is a micro switch, with a first state corresponding to the operating point of the micro switch and a second state corresponding to the open point of the micro switch.

[0081] In some embodiments, the actual number of motion steps consists of a first stroke component and a second stroke component; wherein, the first stroke component is the number of idle steps when the stepper motor overcomes the gear meshing gap during the reverse start-up phase; the second stroke component is the number of effective displacement steps when the moving component moves with the stepper motor and releases the measuring unit until a disconnection signal corresponding to the second state is generated; and the backlash difference corresponds to the number of idle steps.

[0082] In some embodiments, the backflip compensation device further includes a correction section configured to correct the basic theoretical number of steps based on the current ambient temperature and according to a preset temperature drift coefficient model, thereby obtaining the theoretical number of steps.

[0083] In some embodiments, the backlash compensation device further includes a judgment and generation section, configured to judge whether the backlash is within a preset effective range; if the backlash exceeds the effective range, a fault warning signal is generated and the calibration operation of the stepper motor is stopped.

[0084] This disclosure also provides a computer-readable storage medium storing at least one instruction that is executed by a processor to implement the backhaul difference compensation method as described in the above embodiments.

[0085] This disclosure also provides a computer program product including computer instructions stored in a computer-readable storage medium; a processor of a computing device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computing device to perform the backhaul difference compensation method described in the above embodiments.

[0086] Those skilled in the art will recognize that the functions described in this disclosure in one or more of the examples above can be implemented using hardware, software, firmware, or any combination thereof. When implemented in software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or code on a computer-readable medium. Computer-readable media include computer storage media and communication media, wherein communication media include any medium that facilitates the transfer of a computer program from one place to another. Storage media can be any available medium accessible to a general-purpose or special-purpose computer.

[0087] It should be noted that the technical solutions described in this disclosure can be combined arbitrarily as long as they do not conflict.

[0088] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A hysteresis compensation system, characterized in that, The backlash compensation system, applied to head-up display (HUD) devices, includes: A stepper motor is configured to drive the movement of the moving components of the HUD; The measuring unit is configured to switch states under the influence of the active component; The controller is configured to count the actual number of steps the stepper motor takes during the process of the active component pushing the measuring unit from a first state to a second state, wherein the signals corresponding to the first state and the second state are opposite; and, Based on the actual number of steps and the theoretical number of steps, the backlash difference of the stepper motor is determined. The theoretical number of steps is the theoretical number of steps required for the stepper motor when the measurement unit switches from the first state to the second state.

2. The hysteresis compensation system according to claim 1, characterized in that, The actual number of steps is the number of steps the stepper motor moves between the time the controller receives the turn-on signal when the measuring unit is in the first state and the time the controller receives the turn-off signal when the measuring unit is in the second state.

3. The hysteresis compensation system according to claim 2, characterized in that, The controller is configured to control the stepper motor to drive the movable component to move in a first direction; and, When a signal indicating that the measuring unit is in a compressed state is received, the stepper motor is controlled to drive the movable component to move in a second direction opposite to the first direction, and the number of steps of the stepper motor is counted until a signal indicating that the measuring unit is in a released state is received, at which point the actual number of steps is obtained.

4. The hysteresis compensation system according to claim 1, characterized in that, The theoretical number of steps is determined based on the differential travel length of the measuring unit and the transmission ratio of the stepper motor driving the moving component.

5. The hysteresis compensation system according to claim 1, characterized in that, The measuring unit is a micro switch, the first state corresponds to the operating point of the micro switch, and the second state corresponds to the disconnecting point of the micro switch.

6. The hysteresis compensation system according to claim 1, characterized in that, The actual number of steps is composed of a first stroke component and a second stroke component; Wherein, the first stroke component is the number of idle steps of the stepper motor when it overcomes the gear meshing gap during the reverse start-up phase; The second stroke component is the effective displacement steps when the active component moves with the stepper motor and releases the measuring unit until the disconnection signal corresponding to the second state is generated; The return difference corresponds to the number of idle steps.

7. The hysteresis compensation system according to claim 1, characterized in that, The controller is configured to correct the basic theoretical number of steps based on the current ambient temperature and according to a preset temperature drift coefficient model, thereby obtaining the theoretical number of steps.

8. The hysteresis compensation system according to claim 1, characterized in that, The controller is configured to determine whether the backhaul difference is within a preset effective range; If the backlash exceeds the effective range, a fault warning signal is generated and the calibration operation of the stepper motor is stopped.

9. A method for compensating for hysteresis, characterized in that, The backhaul error compensation method includes: The actual number of steps and the theoretical number of steps of the stepper motor are obtained. The actual number of steps is the actual number of steps taken by the stepper motor to drive the active component of the HUD to switch the measurement unit from the first state to the second state. The theoretical number of steps is the theoretical number of steps required by the stepper motor when the measurement unit switches from the first state to the second state. The signals corresponding to the first state and the second state are opposite. The backlash difference of the stepper motor is determined based on the actual number of steps and the theoretical number of steps.

10. A backlash compensation device, characterized in that, The backhaul difference compensation device includes: an acquisition part and a determination part; The acquisition section is configured to acquire the actual number of steps and the theoretical number of steps of the stepper motor. The actual number of steps is the actual number of steps taken by the stepper motor driving the active component of the HUD to push the measurement unit from a first state to a second state. The theoretical number of steps is the theoretical number of steps required by the stepper motor when the measurement unit switches from the first state to the second state. The signals corresponding to the first state and the second state are opposite. The determining component is configured to determine the backlash difference of the stepper motor based on the actual number of steps and the theoretical number of steps.

11. A head-up display device, characterized in that, The head-up display device includes a controller and a display unit; wherein... The controller is configured to, in response to a received reverse adjustment command, drive the stepper motor of the display unit to run the number of steps corresponding to the backlash difference, and then drive the stepper motor to run the number of steps corresponding to the reverse adjustment command. The display unit is configured to be driven by the controller, wherein the stepper motor rotates to drive the movable component to adjust the angle, so as to obtain the adjusted image display height; And, the image is displayed at the adjusted image display height position on the windshield.

12. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores at least one instruction, which is executed by a processor to perform the function of the controller in the backhaul compensation system as described in any one of claims 1 to 8.

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