Optical zoom motor stability automated compression test method and system

Abstract

The embodiment of the application provides a kind of optical zoom motor stability automation pressure test method and system, it is related to optical equipment stability test technical field.The method can be according to the pressure test parameter obtained to control optical zoom motor to execute cyclic test movement and collect pressure test data.Wherein, the pressure test data include in the process of executing cyclic test movement, the actual return position determined by controlling the high-low level jump point of return voltage sampling.The core step loss data is then calculated based on theoretical motion data and pressure test data, and the pressure test result information is generated according to the core step loss data.The method can realize the preset trajectory reciprocating motion of optical zoom motor and the automatic acquisition of key position pressure test data, accurately simulate the long-term working condition of optical zoom motor in aging scene and life scene, efficiently detect the stability indicators such as step loss and positioning deviation of optical zoom motor, and improve the stability test efficiency.

Description

Technical Field

[0001] This application relates to the field of optical equipment stability testing technology, and in particular to an automated stress testing method and system for the stability of an optical zoom motor. Background Technology

[0002] The optical zoom motor is a key adjustment component in optical image acquisition equipment, used to adjust the acquisition parameters of the equipment. The optical zoom motor drives the lens group within the device to move precisely along the optical axis, thereby achieving continuous changes in the focal length for optical image acquisition. This adapts to the imaging requirements of objects at close or distant locations, ensuring clear imaging of objects on the image sensor while maintaining lossless image quality.

[0003] During use, optical zoom motors accumulate errors and experience hardware wear over time, reducing the stability of the zoom process. Therefore, optical image acquisition equipment requires stability testing of the optical zoom motor to assess its stepping control stability, adjustment performance, and lifespan. This stability testing necessitates disassembling the module and using a high-precision laser rangefinder to accurately measure its adjustment parameters.

[0004] However, stability testing relies on manual operation, resulting in low testing efficiency and susceptibility to human error. Furthermore, disassembling modules can damage the product structure, while high-precision laser ranging equipment is expensive, highly dependent on the equipment, and lacks reliable data, making long-term continuous testing impossible. Summary of the Invention

[0005] In view of this, embodiments of this application provide an automated stress testing method and system for the stability of an optical zoom motor, in order to solve the problem of low efficiency in stability testing.

[0006] According to a first aspect of this application, an automated stress testing method for the stability of an optical zoom motor is provided, the method comprising: Obtain stress test parameters, which include test modes and motion parameters corresponding to the test modes; the test modes include at least one of aging test modes and life test modes. The optical zoom motor is controlled to perform a cyclic test motion according to the pressure test parameters to collect pressure test data. The pressure test data includes the actual return position determined by controlling the optical zoom motor to return to the reference positioning point during the cyclic test motion. The reference positioning point is the high-low level transition point of the optical zoom motor voltage sampling. Core step loss data is calculated based on theoretical motion data and the pressure test data; the core step loss data includes motor step loss values ​​calculated by comparing the theoretical reference position in the theoretical motion data with the actual regression position. The stress test results are generated based on the core step loss data. The stress test results include the cumulative step loss deviation of the motor step loss value during multiple cyclic test movements.

[0007] In some embodiments, controlling the optical zoom motor to perform cyclic test motion according to the pressure test parameters to collect pressure test data includes: Read the test mode from the stress test parameters; When the test mode includes the aging test mode, the optical zoom motor is driven to perform smooth and continuous zoom movement according to the preset stroke node, and the pressure test data is collected after each cycle of zoom movement is completed. When the test mode includes the life test mode, the optical zoom motor is driven to switch back and forth between key magnifications according to the reciprocating motion logic based on lens characteristics, and the pressure test data is collected at preset intervals.

[0008] In some embodiments, driving the optical zoom motor to perform smooth and continuous zoom movements according to preset travel nodes includes: Acquire theoretical motion data, which is a complete zoom stroke parameter library formed by pre-recording the theoretical motion values ​​of the optical zoom motor at each magnification. Extract the theoretical motion values ​​from the theoretical motion data; The optical zoom motor is driven based on the theoretical motion values ​​and the number of cycles, and the focus group of the optical zoom motor is controlled to move back and forth a preset number of steps at each magnification.

[0009] In some embodiments, the optical zoom motor is driven to switch back and forth between key magnifications according to a reciprocating motion logic based on lens characteristics, including: Obtain the lens characteristics supported by the optical zoom motor, including wide-angle and telephoto characteristics; A reciprocating motion logic is set according to the lens characteristics, and the reciprocating motion logic is used to realize the reciprocating motion cycle between the wide-angle characteristics, the telephoto characteristics and the wide-angle characteristics; The optical zoom motor is driven to switch back and forth between the two key magnifications, the lowest and the highest, based on the theoretical motion values ​​and the number of cycles of the optical zoom motor.

[0010] In some embodiments, controlling the optical zoom motor to perform cyclic test motion according to the pressure test parameters to collect pressure test data includes: Define core variables, including the number of movement steps, voltage sampling value, positioning marker, and step loss related variables; the step loss related variables are used to record the step loss value in each cycle during the cyclic test movement. Set initial motion parameters, including an initial coarse adjustment step size; Based on the initial motion parameters and the configured number of cycles, the cyclic motion parameters are calculated by gradually reducing the initial coarse adjustment step size; At the beginning of each cycle, a pre-motion reference is recorded, which includes the current step size state of the zoom group and focus group in the optical zoom motor. The optical zoom motor is driven to move according to the cyclic motion parameters, and the sampled voltage value is obtained during the movement of the optical zoom motor.

[0011] In some embodiments, core step loss data is calculated based on theoretical motion data and the pressure test data, including: By comparing the sampled voltage value with the voltage reference threshold, the movement direction of the optical zoom motor is determined, and the number of commanded movement steps of the optical zoom motor is continuously recorded. When the sampled voltage value is detected to cross the voltage reference threshold, the actual number of movement steps is obtained. The actual number of movement steps is the number of movement steps recorded when the sampled voltage value is detected to cross the voltage reference threshold again in the opposite direction of the movement direction. When the commanded number of steps equals the actual number of steps, reset the step loss-related variables; When the commanded number of steps is not equal to the actual number of steps, the motor step loss value is calculated based on the commanded number of steps and the actual number of steps, and the motor step loss value is recorded using the step loss related variables; the motor step loss value is the difference between the commanded number of steps and the actual number of steps.

[0012] In some embodiments, generating stress test result information based on the core step loss data includes: Obtain motor step loss values ​​corresponding to multiple cyclic test motion processes; The multiple lost step values ​​of the motor are accumulated to the step length reference value to obtain the accumulated lost step deviation; the accumulated lost step deviation is used to characterize the total lost step amount of the optical zoom motor throughout the entire range. Obtain preset stress test judgment conditions, which include step loss threshold, step loss fluctuation threshold and cumulative step loss threshold; Based on the preset stress test judgment conditions, the motor step loss value, and the cumulative step loss deviation, the stress test result information is generated; wherein, when the motor step loss value exceeds the step loss threshold, and / or the fluctuation of multiple motor step loss values ​​exceeds the step loss fluctuation threshold, and / or the cumulative step loss deviation exceeds the cumulative step loss threshold, the stress test result information including stability fault results is generated.

[0013] In some embodiments, when the stress test result information includes the stability failure result, the method further includes: The optical zoom motor is calibrated using the cumulative step loss deviation; wherein, when the cumulative step loss deviation is in a first parameter range, the digital zoom parameters of the optical zoom motor are adjusted; and when the cumulative step loss deviation is in a second parameter range, the number of motion steps of the optical zoom motor is corrected according to the cumulative step loss deviation. Get the motion parameters for the current loop; When the detection step size of the motion parameters in the current cycle is reduced to the minimum step size, the duty cycle of the optical zoom motor is adjusted to a stationary state.

[0014] In some embodiments, the method further includes: Record the number of zoom cycles performed by the optical zoom motor per unit time. When the number of zoom cycles reaches a preset feedback threshold, a real-time stress test command is generated. In response to the real-time stress test command, a real-time stress test is performed on the optical zoom motor to obtain the real-time stress test result; The number of motion steps of the optical zoom motor is corrected based on the real-time pressure test results.

[0015] According to a second aspect of this application, an automated stress testing system for the stability of an optical zoom motor is provided, the system comprising: The parameter acquisition module is used to acquire stress test parameters, which include test modes and motion parameters corresponding to the test modes; the test modes include at least one of aging test modes and life test modes. The motion control module is used to control the optical zoom motor to perform cyclic test motion according to the pressure test parameters in order to collect pressure test data; the pressure test data includes the actual return position determined by controlling the optical zoom motor to return to the reference positioning point during the execution of the cyclic test motion; the reference positioning point is the high and low level transition point of the voltage sampling of the optical zoom motor; The step loss calculation module is used to calculate core step loss data based on theoretical motion data and the pressure test data; the core step loss data includes motor step loss values ​​calculated by comparing the theoretical reference position in the theoretical motion data with the actual regression position; The result generation module is used to generate stress test result information based on the core step loss data. The stress test result information includes the cumulative step loss deviation of the motor step loss value during multiple cyclic test movements.

[0016] By employing the above technical solution, this application provides an automated stress testing method and system for the stability of an optical zoom motor. The method controls the optical zoom motor to perform cyclic test motions and collect stress test data according to the acquired stress test parameters. The stress test data includes the actual return position determined by controlling the high and low level transition points of the optical zoom motor's return voltage sampling during the cyclic test motion. Then, core step loss data is calculated based on theoretical motion data and stress test data, and stress test result information is generated based on the core step loss data. This method enables the automatic collection of stress test data for the preset trajectory reciprocating motion of the optical zoom motor and key positions, accurately simulating the long-term working state of the optical zoom motor under aging and lifespan scenarios, efficiently detecting stability indicators such as step loss and positioning deviation of the optical zoom motor, and improving the efficiency of stability testing.

[0017] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0018] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the automated pressure testing method for the stability of an optical zoom motor provided in an embodiment of this application; Figure 2 This is a schematic diagram of a fully automated closed-loop process provided in an embodiment of this application; Figure 3 This is a schematic diagram of the PI point detection principle provided in an embodiment of this application; Figure 4 This is a schematic diagram of the stability data acquisition and persistent storage process provided in the embodiments of this application; Figure 5 This is a schematic diagram of the real-time stress testing process provided in the embodiments of this application; Figure 6 This is a schematic diagram of the structure of an automated pressure testing system for the stability of an optical zoom motor provided in an embodiment of this application. Detailed Implementation

[0019] The present application will be described in detail below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present application can be combined with each other.

[0020] In this embodiment, the optical zoom motor is a key adjustment component in the optical image acquisition device, used to adjust the acquisition parameters of the optical image acquisition device. The optical zoom motor can drive the lens group in the device to move precisely along the optical axis, thereby realizing continuous change of the focal length of optical image acquisition to adapt to the imaging requirements of objects at near or far distances, so that the objects are clearly imaged on the image sensor and the image quality remains intact.

[0021] In some embodiments, an optical zoom motor may include multiple functional groups, such as a zoom group and a focus group. The zoom group can be used to change the focal length, control the zooming in or out shooting distance, and achieve the effects of telephoto and wide-angle modes. Since a single zoom group may struggle to simultaneously meet the demands of high magnification, high image quality, and fast response, an optical zoom motor may include two or more independent zoom groups working together for motion control, such as an optical zoom motor comprising a first zoom group (ZOOM1) and a second zoom group (ZOOM2).

[0022] The focus group, also known as the zoom group, is used to adjust the focal length to make the subject appear sharper. In complex lenses, the zoom group and focus group need to work together to achieve synchronized focusing, ensuring the image remains sharp throughout the zoom process. The focus group works in conjunction with the zoom group to adjust the focal length for different focal lengths. During image acquisition, the focus group moves back and forth to ensure the subject is in focus, thus transforming a blurry image into a sharp one.

[0023] During use, optical zoom motors experience accumulated errors and hardware wear over time, reducing the stability of the zoom process. For example, the MS41968 optical zoom motor, compatible with the OV50e40 image sensor, may experience stability issues under prolonged operation.

[0024] Therefore, optical image acquisition equipment requires stability testing of the optical zoom motor to detect its step control stability, adjustment performance, and lifespan. In some embodiments, stability testing requires disassembling the entire image acquisition device into modules and using a high-precision laser rangefinder to accurately measure the module adjustment parameters to determine whether the optical zoom motor is experiencing step loss.

[0025] However, stability testing relies on manual operation, resulting in low testing efficiency and susceptibility to human error. Furthermore, disassembling modules can damage the product structure, while high-precision laser ranging equipment is expensive, highly dependent on the equipment, and lacks reliable data, making long-term continuous testing impossible.

[0026] To address the problem of low efficiency in stability testing, some embodiments of this application provide an automated stress testing method for the stability of an optical zoom motor. The method controls the optical zoom motor to reciprocate along a preset trajectory and automatically collects stress test data at key locations. This accurately simulates the long-term working state of the optical zoom motor under aging and lifespan scenarios, efficiently detects stability indicators such as step loss and positioning deviation of the optical zoom motor, and improves the efficiency of stability testing.

[0027] The method can be applied to image acquisition devices including optical zoom motors, or electronic devices that establish a communication connection with the image acquisition device and have data processing capabilities. These electronic devices include, but are not limited to, computers, servers, mobile terminals, smart wearable devices, and industrial control computers. For ease of description, this embodiment uses the image acquisition device as the execution subject of the method. For example, the core execution steps of the method can be developed based on embedded C language and run directly on the embedded Linux platform of the image acquisition device. This achieves the goal of motor control and data reading without the need for additional external dedicated testing equipment, relying solely on the driver node, and features lightweight deployment, high hardware compatibility, and rapid implementation. It should be understood that the method can also be applied to other types of execution subjects, which are not shown in this embodiment. Figure 1 As shown, the method includes: S101. Obtain the pressure test parameters.

[0028] When performing stability stress testing on an optical zoom motor, stress testing parameters can be obtained first. These parameters include the test mode and the corresponding motion parameters. The test mode includes at least one of an aging test mode and a lifespan test mode. The aging test mode is used to perform aging tests on the optical zoom motor, i.e., to test the long-term operating condition of the optical zoom motor under aging scenarios. The lifespan test mode is used to perform lifespan tests on the optical zoom motor, i.e., to test the long-term operating condition of the optical zoom motor under lifespan scenarios.

[0029] In some embodiments, the stress test parameters may include zoom motion trajectory parameters. These parameters are used to control the optical zoom motor to perform zoom motion along a specific trajectory during stability stress testing, simulating different usage scenarios.

[0030] Zoom motion trajectory parameters can include theoretical motion data. This theoretical motion data is a complete zoom stroke parameter library formed by pre-recording the theoretical motion values ​​of the optical zoom motor at various magnifications. For example, by pre-recording the theoretical motion values ​​of the three groups ZOOM1, ZOOM2, and FOCUS in the optical zoom motor at various magnifications, a complete zoom stroke parameter library is formed, serving as the core execution basis for the motor's automated motion. This parameter library comprehensively covers the entire working zoom range of the motor, ensuring that the stress test scenario closely matches the actual working logic, effectively avoiding distortion of stress test results caused by invalid motion, and laying the foundation for accurate fault detection.

[0031] The zoom motion trajectory parameters support flexible configurability. By presetting multiple sets of core control parameters, it supports custom configuration of test scenarios and execution processes, thereby quickly adapting to different load testing needs without modifying the core code, greatly improving versatility and reusability.

[0032] Flexible configurable parameters include the number of load testing cycles, test mode switching, and data acquisition interval. The number of load testing cycles supports both finite and infinite loop modes; infinite loops meet the needs of long-term stability testing. Test mode switching allows for flexible switching between aging and lifespan modes, each corresponding to different motor motion logic and covering fault detection in various application scenarios. The data acquisition interval can be configured to track the frequency of critical positioning data collection, ensuring the integrity of load testing data while optimizing storage resource consumption and improving the feasibility of long-term testing.

[0033] like Figure 2 As shown, in some embodiments, the pressure test parameters may also include test environment parameters, i.e., the test environment parameters can be customized through pre-test preparation. The test environment parameters can support flexible adjustment of key external conditions such as the placement of the optical zoom module, the temperature and humidity of the test environment, and the atmospheric pressure of the environment. It can specifically measure the working stability of the module under different environmental conditions, comprehensively cover the complex scenarios in the actual application of motors, and improve the reference value of the pressure test results.

[0034] S102. Control the optical zoom motor to perform cyclic test motion according to the pressure test parameters in order to collect pressure test data.

[0035] After obtaining the stress test parameters, the optical zoom motor can be controlled to perform cyclic test motions according to these parameters. This simulates the actual use of the optical zoom motor and collects stress test data during the cyclic test motions. The stress test data includes the actual return position determined by controlling the optical zoom motor to return to the reference positioning point during the cyclic test motions.

[0036] The reference positioning point is the high / low level transition point of the optical zoom motor voltage sampling. After the optical lens system of the image acquisition device is started, the reference positioning point (PI point) can be found according to the startup program. After finding the PI point, an initialization command is sent to the optical zoom motor to control the optical zoom motor to move the lens group to the initial position. The reference positioning point is the reference point in the motion component feedback control algorithm.

[0037] Based on a reference positioning point, a PI position control algorithm for the optical zoom motor can be configured. The PI position control algorithm is a feedback control algorithm used in the motor control process to adjust the accuracy and stability of the motor position. The PI position control algorithm can perform positioning based on two feedback control parameters: duty cycle (P) and subdivision step (I). Duty cycle (P) is a parameter in the Pulse Width Modulation (PWM) process, used to adjust the output voltage or current according to the error signal to minimize the difference between the optical zoom motor position and the target position.

[0038] Since the current position of the optical zoom motor cannot be directly obtained, the control chip for the optical zoom motor provides a PI position input / output interface (IO). An optocoupler is also installed inside the optical zoom motor. The movement of the optical zoom motor blocks some light, causing a change in the output voltage of the PI position IO pin of the control chip.

[0039] In some embodiments, a baffle may be provided on the actuator of the optical zoom motor. The light-emitting diode D1 continues to emit light under the power supply, and the corresponding phototransistor Q1 is turned on when it is illuminated, so that the control module receives a low level. When the optical zoom motor drives the lens group to move to a preset position, the baffle blocks the light emitted by the light-emitting diode D1, and the corresponding phototransistor Q1 is turned off, so that the control module receives a high level.

[0040] It should be noted that, depending on the actual application, the baffle can be set to be relatively long, so that there is only one level state transition throughout the entire movable path, that is, a high-low level transition occurs in the monitoring signal. Assuming that the moving component is currently at position B, which is closer to the starting end, the control module receives a low level at this time. When the moving component moves to the preset position A, the control module receives a high level. Since the baffle is long enough, the control module receives a high level at all positions from the preset position A to the terminal. Assuming that the moving component is currently at position C, which is closer to the terminal, the control module receives a high level at this time. When the target component moves to the preset position A, the control module receives a low level. The control module receives a low level at all positions from the starting end to the preset position A. It can be seen that the control module only receives one high-low level transition to ensure accurate location of the motion reference point.

[0041] For example, such as Figure 3 As shown, taking the position point corresponding to the transition from low level to high level as the positioning reference point as defined by the level transition rule, when the level in the monitoring signal is low, it means that the target is at a certain position between the starting end and the preset position A, so the target direction is the direction of moving towards the high level; when the first level is high, it means that the target is at a certain position between the preset position A and the end, so the target direction is the direction of moving towards the low level.

[0042] Therefore, to locate the PI point, the optical zoom motor can control the lens assembly to move along the entire movement path, thereby determining the PI point based on the position of the lens assembly corresponding to the high and low levels of the monitoring signal. Alternatively, the current monitoring signal level can be acquired before locating the PI point, and then the motor can move in different directions based on the high and low levels, mitigating the problem of motor kinetic energy being converted into heat energy.

[0043] Since there is a certain difference between the actual and theoretical movement of the motor after the control command is issued, and this difference is related to the set duty cycle, motor speed, retrace error, and step loss, in some embodiments, the stability of the PI point finding process can be increased by finding the number of subdivision steps that best matches the theoretical and actual movement of the motor without step loss, and by finding the retrace error of the module. This is achieved by adjusting motor parameters such as the number of subdivision steps and the retrace error.

[0044] For example, to measure PI points, interfaces for dynamically adjusting the duty cycle during movement and when stationary, motor speed, and querying missed steps can be added to the motor drive module. Automated traversal measurement of motor stability can be achieved using a laser rangefinder with an accuracy of 1-2µm and a host computer. The host computer can send commands to the slave computer or drive module and read data from the laser rangefinder.

[0045] In some embodiments, when controlling the optical zoom motor to perform cyclic test motions according to the pressure test parameters to collect pressure test data, the test mode can be read from the pressure test parameters first, and the optical zoom motor can be controlled to perform different cyclic test motions according to different test modes. When the test mode includes an aging test mode, the optical zoom motor is driven to perform smooth and continuous zoom motions according to preset stroke nodes, and pressure test data is collected after each cycle of zoom motion is completed.

[0046] When driving the optical zoom motor to perform smooth and continuous zoom motion, theoretical motion data can be acquired first, and theoretical motion values ​​can be extracted from the theoretical motion data. Then, the optical zoom motor is driven based on the theoretical motion values ​​and the number of cycles, and the focus group of the optical zoom motor is controlled to move back and forth for a preset number of steps at each magnification.

[0047] In the lifespan test mode, the optical zoom motor is driven to switch back and forth between key magnifications according to a reciprocating motion logic based on lens characteristics, and stress test data is collected at preset intervals. While driving the optical zoom motor to switch back and forth between key magnifications, the lens characteristics supported by the optical zoom motor are acquired, including wide-angle and telephoto characteristics. The reciprocating motion logic is then set according to these lens characteristics, enabling a reciprocating motion cycle between wide-angle, telephoto, and wide-angle characteristics. Based on the theoretical motion values ​​and cycle count of the optical zoom motor, it is then driven to switch back and forth between the lowest and highest key magnifications.

[0048] For example, a motion control module can be deployed to control the automated execution of pressure-related movements by an optical zoom motor. The motion control module is the core execution unit that triggers motor step loss faults, enabling automated and scenario-specific precise motor movement. The core process of the motion control module consists of two testing modes: aging test mode and lifespan test mode.

[0049] For the aging test mode, the motor can be driven to complete a smooth and continuous zoom movement according to preset stroke nodes, which highly simulates zoom operation in real-world scenarios. Based on the theoretical values ​​of each magnification of the optical zoom motor, the motor is driven to run, and at each magnification, the FOCUS group is controlled to move back and forth in small steps to simulate the autofocus (AF) scenario in actual work, and the continuous test is completed according to the configured number of cycles.

[0050] For lifespan testing, a high-frequency reciprocating motion logic of "wide-angle (WIDE) - telephoto (TELE) - wide-angle (WIDE)" can be adopted to simulate the high-frequency magnification switching operation of the motor, improving lifespan testing efficiency and closely aligning with the long-term wear and tear scenarios in mass production. Therefore, based on the theoretical values ​​of the optical zoom motor, the motor can be driven to switch back and forth between the two key magnifications, the lowest (WIDE) and the highest (TELE), to complete the durability test according to the configured number of cycles.

[0051] Simultaneously, a differentiated data acquisition triggering strategy is adopted. In aging test mode, missed step data is collected immediately after each cycle, while in life test mode, missed step data is collected at preset intervals. All collected stress test data can be stored locally in TXT format, maximizing storage utilization and operational efficiency for long-term testing while ensuring data validity. Furthermore, the control program running the motion control module supports flexible configuration of core control parameters, adapting to different stress test requirements without modifying the core code, achieving efficient cyclic execution.

[0052] To collect stress test data, in some embodiments, the optical zoom motor is controlled to perform cyclic test motion according to the stress test parameters. When collecting stress test data, core variables can be defined first. These core variables include the number of movement steps, voltage sampling value, positioning marker, and step loss-related variables. The step loss-related variables are used to record the step loss value in each cycle during the cyclic test motion.

[0053] Next, initial motion parameters are set, including an initial coarse adjustment step size. Based on the initial motion parameters and the configured number of cycles, cyclic motion parameters are calculated by gradually reducing the initial coarse adjustment step size. At the beginning of each cycle, a pre-motion reference is recorded, which includes the current step size state of the zoom group and focus group in the optical zoom motor. The optical zoom motor is then driven according to the cyclic motion parameters, and sampled voltage values ​​are acquired during the optical zoom motor's movement.

[0054] For example, such as Figure 4 As shown, the motion control module in the image acquisition device can calculate lost steps by finding PI points. It uses ADC voltage sampling to find mechanical PI points (i.e., positioning reference points) for the lens's three groups: ZOOM1, ZOOM2, and FOCUS. Throughout the process, it focuses on monitoring, recording, and calibrating the lost steps during motor movement to ensure the accuracy of the reference point positioning.

[0055] Because optical zoom motors may miss steps when moving due to issues such as load or power, the motion control module can track the missed step deviation in real time while searching for the positioning reference point. This allows the optical zoom motor to stop precisely at the PI point while correcting the missed step error.

[0056] During stress testing, parameter initialization can be performed first to prepare for step loss detection. This involves defining core variables such as the number of steps, ADC sampling values, and positioning markers, as well as specific step loss-related variables such as z1_steploss_flag, z2_steploss_flag, and f_steploss_flag to record the step length baseline value before each motor's movement. Furthermore, pre-movement baselines such as z1_steploss, z2_steploss, and f_steploss can be defined to accumulate the final step loss deviation.

[0057] By setting initial motion parameters, an initial coarse adjustment step size, such as 256 steps, is set for the three groups of the optical zoom motor. At the same time, all step loss-related variables are reset to 0 to ensure that each PI search starts from zero step loss deviation.

[0058] Then, by performing PI point search and full-process step loss detection, the entire stress test process is divided into 20 cycles, and the adjustment step size in each cycle is gradually reduced. For example, during the cycle, the adjustment step size is adjusted from 256 steps to 64 steps, 16 steps, 4 steps, and 1 step in turn. Thus, at each step of PI point search from coarse adjustment to fine adjustment, step loss is monitored and processed.

[0059] Furthermore, by recording a baseline before movement, preparations are made for step loss comparison. Specifically, at the beginning of each loop, the current step size status of three motors—z1_steploss_flag, z2_steploss_flag, and f_steploss_flag—is recorded as a baseline value to determine whether steps will be lost subsequently. This is equivalent to recording the expected position of the optical zoom motor. Then, the motor is driven to move, and real-time sampling and preliminary positioning are performed. This is achieved by configuring the motor driver chip, setting a 135% duty cycle and synchronization speed, driving the motor to move at the set step size, and monitoring the sampled voltage value during the optical zoom motor's movement.

[0060] In some embodiments, the stress test data collected during the stability stress test can be persistently stored as a basis for determining step loss faults. That is, the motion control module realizes the entire process of stress test data acquisition, parsing, storage, and verification, providing a traceable quantitative basis for determining step loss faults. By reading key data, the optical zoom motor can be periodically controlled to return to the PI point (reference positioning point) during cyclic testing. By comparing the theoretical position with the actual return position, the step loss value of the optical zoom motor can be accurately calculated, serving as the core data basis for judging the working stability of the optical zoom motor.

[0061] It can also perform data parsing and verification, extract and verify the validity of the core missing step data collected. If data parsing fails, it will provide real-time feedback of abnormal information, which will help testers to troubleshoot hardware communication failures in a timely manner and ensure the continuity of the stress testing process.

[0062] For the load test data that has passed the verification, real-time monitoring and persistent storage of the data are also possible. For example, the loop progress and optical zoom motor working data can be printed in real time during the load test, which makes it convenient for testers to monitor the test status in real time. At the same time, all valid data are stored in the local log file in append write mode to achieve long-term retention of the load test data and avoid data loss due to unexpected situations such as system restart.

[0063] After the stress test is completed, the step loss data of different loop stages in the log file can be compared. If the step loss data exceeds the preset threshold or abnormal fluctuations are found, it can be determined that there is a stability fault in the optical zoom motor. This provides accurate and detailed data support for subsequent root cause analysis of the fault, hardware optimization of the optical zoom motor and improvement of the control algorithm.

[0064] S103. Calculate core step loss data based on theoretical motion data and pressure test data.

[0065] After collecting the stress test data, core step loss data can be calculated based on the theoretical motion data and the stress test data. This core step loss data includes the motor step loss value calculated by comparing the theoretical reference position in the theoretical motion data with the actual regression position.

[0066] In some embodiments, when calculating core step loss data based on theoretical motion data and pressure test data, the motion direction of the optical zoom motor can be determined by comparing the sampled voltage value with the voltage reference threshold, and the number of commanded motion steps of the optical zoom motor can be continuously recorded.

[0067] When the sampled voltage value is detected to cross the voltage reference threshold, the actual number of movement steps is obtained, wherein the actual number of movement steps is the number of movement steps recorded when the sampled voltage value is detected to cross the voltage reference threshold again in the opposite direction of the movement direction.

[0068] For example, the lens can be driven by an optical zoom motor in the opposite direction of the motion direction to find a new motion reference point from the current position. This allows it to be determined that when the motion reference point is found again, i.e. when the sampled voltage value crosses the voltage reference threshold again, the number of steps taken is the actual number of motion steps.

[0069] After obtaining the actual number of steps, the actual number of steps can be compared with the commanded number of steps. If the commanded number of steps equals the actual number of steps, the step loss related variables are reset. If the commanded number of steps does not equal the actual number of steps, a motor step loss value is calculated based on the difference between the commanded number of steps and the actual number of steps. The motor step loss value is then recorded using the step loss related variables.

[0070] For example, by sampling the ADC voltage value in real time, the direction of motor movement is determined based on the comparison between the sampled voltage value and the voltage reference threshold, while continuously recording the number of commanded movement steps (Z1 / Z2 / F1) of the motor. The voltage reference threshold can be an empirical value, and the number of commanded movement steps is the number of movement steps corresponding to the three groups, which can be recorded in real time through global variables.

[0071] Next, step loss detection and calibration are performed. When the sampled voltage value corresponding to the optical zoom motor is detected to cross the voltage reference threshold, i.e., the movement is approaching the PI point, a step loss is determined by comparing the commanded number of steps with the actual number of steps. The step loss detection logic is as follows: calculate the difference between the actual number of steps and the commanded number of steps. If the actual number of steps and the commanded number of steps are not equal, it indicates a step loss. The deviation value is then recalculated, and the number of lost steps is recorded using z1_steploss_flag so that the optical zoom motor can compensate for the lost steps. If the two are equal, it indicates no step loss, and the step loss flag can be reset to 0.

[0072] S104. Generate stress test result information based on core step loss data.

[0073] After calculating the core step loss data, stress test results are generated based on the core step loss data. These results include the cumulative step loss deviation of the motor step loss value during multiple cyclic test movements.

[0074] To generate stress test results, in some embodiments, when generating stress test results based on core step loss data, the motor step loss values ​​corresponding to multiple cyclic test motion processes can be obtained first, and the multiple motor step loss values ​​can be accumulated to the step length reference value to obtain the cumulative step loss deviation. The cumulative step loss deviation is used to characterize the total step loss amount of the optical zoom motor throughout the entire process.

[0075] Next, preset stress test judgment conditions are obtained, including a step loss threshold, a step loss fluctuation threshold, and a cumulative step loss threshold. Then, stress test result information is generated based on the preset stress test judgment conditions, the motor step loss value, and the cumulative step loss deviation. Specifically, when the motor step loss value exceeds the step loss threshold, and / or the fluctuation of multiple motor step loss values ​​exceeds the step loss fluctuation threshold, and / or the cumulative step loss deviation exceeds the cumulative step loss threshold, stress test result information including stability fault results is generated.

[0076] For example, after calculating and obtaining the core step loss data, step loss deviation can be accumulated. The corrected step loss deviation value (z1_steploss_flag) is accumulated into z1_steploss, and finally the total number of steps lost for the entire motor is obtained, i.e., the accumulated step loss deviation. The step loss detection, calibration, and accumulation logic for ZOOM2 and FOCUS groups is completely the same, and will not be described in detail here.

[0077] Then, based on the motor step loss value collected from the pressure test data in multiple cycles, the fluctuation of the motor step loss value is calculated, and the preset pressure test judgment conditions are used to judge whether the motor step loss value, the fluctuation of the motor step loss value, and the cumulative step loss deviation exceed the reasonable range. When any one of the following conditions is met: the motor step loss value exceeds the step loss threshold, the fluctuation of multiple motor step loss values ​​exceeds the step loss fluctuation threshold, and the cumulative step loss deviation exceeds the cumulative step loss threshold, it is determined that the current optical zoom motor has a stability fault, that is, pressure test result information including the stability fault result is generated.

[0078] In some embodiments, when the stress test results include stability failure results, the cumulative step loss deviation can also be used to calibrate the optical zoom motor. Specifically, when the cumulative step loss deviation is within a first parameter range, the digital zoom parameters of the optical zoom motor are adjusted; when the cumulative step loss deviation is within a second parameter range, the number of motion steps of the optical zoom motor is corrected based on the cumulative step loss deviation.

[0079] For example, when the number of lost steps is less than or equal to 10% of the total travel steps, the step loss deviation can be compensated by digital zoom. When the number of lost steps is greater than 10% of the total travel steps but less than or equal to 30% of the total travel steps, the number of steps moved by the optical zoom motor can be corrected based on the cumulative step loss deviation. Taking a total travel of 100 steps as an example, the first parameter range is [1, 10], and the second parameter range is [11, 30]. The maximum value of the first parameter range is 10, and the minimum value of the second parameter range is 11, that is, the maximum value of the first parameter range is less than the minimum value of the second parameter range.

[0080] After determining the cumulative step loss deviation C according to the method provided in the above embodiments, the optical zoom motor can be calibrated in a corresponding manner based on the parameter range to which the cumulative step loss deviation C belongs. That is, when 1≤C≤10, the digital zoom parameters of the optical zoom motor are adjusted, such as calculating the target focal length by the commanded movement steps, and calculating the actual focal length by the cumulative step loss deviation and the commanded movement steps. Then, the optical focal length error ratio is calculated, i.e., error rate = (target focal length - actual focal length) / target focal length. Then, digital zoom is activated according to the optical focal length error ratio, and the central area of ​​the image is cropped and enlarged by 1 / (1 - optical focal length error ratio) times, so that the final image perspective approximates the perspective of the target focal length.

[0081] Similarly, when 11≤C≤30, the number of steps of the optical zoom motor can be corrected according to the cumulative step loss deviation C. For example, for the target focal length, the cumulative step loss deviation C can be added or subtracted from the corresponding commanded number of steps to compensate for the step loss of the optical zoom motor.

[0082] It should be noted that, since step loss is directional, the actual number of steps may be less than the commanded number of steps, or the actual number of steps may be more than the commanded number of steps. Therefore, in some embodiments, the first parameter interval and the second parameter interval may contain negative values, such as the first parameter interval being [-5, 5] and the second parameter interval being [-25, -6] and [6, 25].

[0083] Next, acquire the motion parameters for the current cycle, and when the detection step size of the motion parameters for the current cycle is reduced to the minimum step size, adjust the duty cycle of the optical zoom motor to a stationary state. For example, fine-tuning can be achieved by monitoring the detection step size. When the step size is reduced to 1 step, the fine-tuning stage begins, and all three groups have completed step loss calibration and the voltage is stable near the reference threshold, indicating that PI point positioning is complete. At this point, it can be confirmed that there are no step losses and the motor has stopped, and the motor duty cycle is adjusted to 50% (stationary state) to avoid secondary step loss due to power deviation when stationary, allowing the motor to stop precisely at the PI point.

[0084] Then, by summarizing the lost steps and positioning results, stress test results are generated. These results can include various key information, such as the final fine-tuning step lengths for the three groups to confirm the PI point positioning accuracy; the total lost steps, i.e., z1_steploss, z2_steploss, f_steploss, etc.; and the positioning completion marker (PIFlag). This key information allows direct determination of whether each motor lost steps during the PI seeker process, the amount of lost steps, and the accuracy of the PI point positioning. Therefore, throughout the entire PI seeker process, every motor movement records the step length baseline, determines lost steps, and calibrates deviations. Lost step detection is integrated throughout the coarse and fine tuning processes. Lost step deviations are accumulated in real time, ultimately outputting quantified lost step data to facilitate tracing the causes of abnormal motor movement. The final PI point positioning accuracy is based on the results after lost step calibration, ensuring positioning precision.

[0085] By applying the technical solutions of the above embodiments, the automated stress testing method for the stability of optical zoom motors described in the above embodiments can effectively improve stress testing efficiency and data reliability, and achieve long-term continuous testing. By constructing an automated, configurable, and full-scenario-coverage stress testing closed loop, it can significantly improve stress testing efficiency and significantly optimize fault detection accuracy, while greatly reducing manual and equipment testing costs, providing efficient and detailed technical support for ensuring the reliability of optical zoom motors.

[0086] In some embodiments, as a refinement and extension of the specific implementation of the above embodiments, in order to fully illustrate the specific implementation process of this embodiment, some embodiments of this application also provide an automated pressure testing method for the stability of an optical zoom motor. The difference between this method and the above embodiments is that it can generate zoom result feedback during the use of the image acquisition device and perform pressure testing in real time, thereby improving the accuracy of each use. Figure 5 As shown, the method includes: S201. Record the number of zoom cycles performed by the optical zoom motor per unit time. S202. When the number of zoom cycles reaches the preset feedback threshold, a real-time stress test command is generated. S203. In response to the real-time stress test command, perform a real-time stress test on the optical zoom motor to obtain the real-time stress test result. S204. Correct the number of motion steps of the optical zoom motor based on the real-time pressure test results.

[0087] To perform real-time stress testing, the image acquisition device can monitor the user's zoom operation during use and record the number of zooms by the optical zoom motor per unit time. The recorded number of zooms is then compared with a preset feedback threshold. When the number of zooms reaches the preset feedback threshold, it indicates that the user has zoomed too many times per unit time, which is likely because the results of multiple zooms do not meet the user's needs. At this point, a real-time stress test command can be generated to trigger the execution of the real-time stress test.

[0088] The image acquisition device can respond to real-time stress test commands and perform real-time stress tests on the optical zoom motor according to the automated stress test process described in the above embodiments to obtain real-time stress test results. For example, during real-time stress testing, the optical zoom motor can be controlled to perform cyclic test motions and collect stress test data according to the acquired stress test parameters. Similarly, the stress test data includes the actual return position determined by controlling the high and low level transition points of the optical zoom motor's return voltage sampling during the cyclic test motion. Then, core step loss data is calculated based on theoretical motion data and stress test data, and real-time stress test results are generated based on the core step loss data. Finally, the number of motion steps of the optical zoom motor is corrected based on the real-time stress test results.

[0089] By applying the technical solutions of the above embodiments, the automated stress testing method for the stability of optical zoom motors described in the above embodiments can be adapted through dual testing modes of aging and lifespan, covering the full-scenario stress testing of optical zoom motors. It simulates both the conventional scenario of continuous smooth zooming and the extreme wear scenario of high-frequency reciprocating motion in wide-angle and telephoto lenses, comprehensively covering actual application conditions and enhancing the engineering reference value of the stress test results. Furthermore, by constructing a fully automated stress testing closed loop of zeroing, movement, acquisition, storage, and cycling, it supports 24 / 7 unlimited cycling and background operation, reducing manual intervention and significantly improving stress testing efficiency and lowering testing costs. Moreover, through persistent storage of data throughout the entire lifecycle, the testing process can be traced back and reproduced, accurately locating the cycle stage, operating condition, and location of step loss faults, achieving full-process traceability and precise fault location, providing accurate data support for motor optimization.

[0090] In some embodiments, as a specific implementation of the automated stress testing method for the stability of the optical zoom motor described in the above embodiments, some embodiments of this application also provide an automated stress testing system for the stability of the optical zoom motor, such as... Figure 6 As shown, the system includes: The parameter acquisition module is used to acquire stress test parameters, which include test modes and motion parameters corresponding to the test modes; the test modes include at least one of aging test modes and life test modes. The motion control module is used to control the optical zoom motor to perform cyclic test motion according to the pressure test parameters in order to collect pressure test data; the pressure test data includes the actual return position determined by controlling the optical zoom motor to return to the reference positioning point during the execution of the cyclic test motion; the reference positioning point is the high and low level transition point of the voltage sampling of the optical zoom motor; The step loss calculation module is used to calculate core step loss data based on theoretical motion data and the pressure test data; the core step loss data includes motor step loss values ​​calculated by comparing the theoretical reference position in the theoretical motion data with the actual regression position; The result generation module is used to generate stress test result information based on the core step loss data. The stress test result information includes the cumulative step loss deviation of the motor step loss value during multiple cyclic test movements.

[0091] By applying the technical solutions of the above embodiments, the automated stress testing system for the stability of an optical zoom motor described in the above embodiments can control the optical zoom motor to perform cyclic test motion and collect stress test data according to the acquired stress test parameters. The stress test data includes the actual return position determined by controlling the high and low level transition points of the optical zoom motor's return voltage sampling during the cyclic test motion. Then, core step loss data is calculated based on theoretical motion data and stress test data, and stress test result information is generated based on the core step loss data. The system can realize the automatic acquisition of preset trajectory reciprocating motion of the optical zoom motor and stress test data at key positions, accurately simulate the long-term working state of the optical zoom motor under aging and lifespan scenarios, efficiently detect stability indicators such as step loss and positioning deviation of the optical zoom motor, and improve the efficiency of stability testing.

[0092] It should be noted that other corresponding descriptions of the functional units involved in the automated stress testing system for the stability of an optical zoom motor provided in the embodiments of this application can be found in the corresponding descriptions in the automated stress testing method for the stability of an optical zoom motor provided in the above embodiments, and will not be repeated here.

[0093] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0094] The embodiments described above are merely examples of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application.

Claims

1. An automated pressure testing method for the stability of an optical zoom motor, characterized in that, The method includes: Obtain stress test parameters, which include test modes and motion parameters corresponding to the test modes; the test modes include at least one of aging test modes and life test modes. The optical zoom motor is controlled to perform a cyclic test motion according to the pressure test parameters to collect pressure test data. The pressure test data includes the actual return position determined by controlling the optical zoom motor to return to the reference positioning point during the cyclic test motion. The reference positioning point is the high-low level transition point of the optical zoom motor voltage sampling. Core step loss data is calculated based on theoretical motion data and the pressure test data; the core step loss data includes motor step loss values ​​calculated by comparing the theoretical reference position in the theoretical motion data with the actual regression position. The stress test results are generated based on the core step loss data. The stress test results include the cumulative step loss deviation of the motor step loss value during multiple cyclic test movements.

2. The method according to claim 1, characterized in that, The optical zoom motor is controlled to perform cyclic test motions according to the pressure test parameters to collect pressure test data, including: Read the test mode from the stress test parameters; When the test mode includes the aging test mode, the optical zoom motor is driven to perform smooth and continuous zoom movement according to the preset stroke node, and the pressure test data is collected after each cycle of zoom movement is completed. When the test mode includes the life test mode, the optical zoom motor is driven to switch back and forth between key magnifications according to the reciprocating motion logic based on lens characteristics, and the pressure test data is collected at preset intervals.

3. The method according to claim 2, characterized in that, Drive the optical zoom motor to perform smooth and continuous zoom movements according to preset travel nodes, including: Acquire theoretical motion data, which is a complete zoom stroke parameter library formed by pre-recording the theoretical motion values ​​of the optical zoom motor at each magnification. Extract the theoretical motion values ​​from the theoretical motion data; The optical zoom motor is driven based on the theoretical motion values ​​and the number of cycles, and the focus group of the optical zoom motor is controlled to move back and forth a preset number of steps at each magnification.

4. The method according to claim 3, characterized in that, Based on the reciprocating motion logic of the lens characteristics, the optical zoom motor is driven to switch back and forth between key magnifications, including: Obtain the lens characteristics supported by the optical zoom motor, including wide-angle and telephoto characteristics; A reciprocating motion logic is set according to the lens characteristics, and the reciprocating motion logic is used to realize the reciprocating motion cycle between the wide-angle characteristics, the telephoto characteristics and the wide-angle characteristics; The optical zoom motor is driven to switch back and forth between the two key magnifications, the lowest and the highest, based on the theoretical motion values ​​and the number of cycles of the optical zoom motor.

5. The method according to claim 1, characterized in that, The optical zoom motor is controlled to perform cyclic test motions according to the pressure test parameters to collect pressure test data, including: Define core variables, including the number of movement steps, voltage sampling value, positioning marker, and step loss related variables; the step loss related variables are used to record the step loss value in each cycle during the cyclic test movement. Set initial motion parameters, including an initial coarse adjustment step size; Based on the initial motion parameters and the configured number of cycles, the cyclic motion parameters are calculated by gradually reducing the initial coarse adjustment step size; At the beginning of each cycle, a pre-motion reference is recorded, which includes the current step size state of the zoom group and focus group in the optical zoom motor. The optical zoom motor is driven to move according to the cyclic motion parameters, and the sampled voltage value is obtained during the movement of the optical zoom motor.

6. The method according to claim 5, characterized in that, The core step loss data is calculated based on theoretical motion data and the pressure test data, including: By comparing the sampled voltage value with the voltage reference threshold, the movement direction of the optical zoom motor is determined, and the number of commanded movement steps of the optical zoom motor is continuously recorded. When the sampled voltage value is detected to cross the voltage reference threshold, the actual number of movement steps is obtained. The actual number of movement steps is the number of movement steps recorded when the sampled voltage value is detected to cross the voltage reference threshold again in the opposite direction of the movement direction. When the commanded number of steps equals the actual number of steps, reset the step loss-related variables; When the commanded number of steps is not equal to the actual number of steps, the motor step loss value is calculated based on the commanded number of steps and the actual number of steps, and the motor step loss value is recorded using the step loss related variables; the motor step loss value is the difference between the commanded number of steps and the actual number of steps.

7. The method according to claim 1, characterized in that, Based on the core step loss data, stress test result information is generated, including: Obtain motor step loss values ​​corresponding to multiple cyclic test motion processes; The multiple lost step values ​​of the motor are accumulated to the step length reference value to obtain the accumulated lost step deviation; the accumulated lost step deviation is used to characterize the total lost step amount of the optical zoom motor throughout the entire range. Obtain preset stress test judgment conditions, which include step loss threshold, step loss fluctuation threshold and cumulative step loss threshold; Based on the preset stress test judgment conditions, the motor step loss value, and the cumulative step loss deviation, the stress test result information is generated; wherein, when the motor step loss value exceeds the step loss threshold, and / or the fluctuation of multiple motor step loss values ​​exceeds the step loss fluctuation threshold, and / or the cumulative step loss deviation exceeds the cumulative step loss threshold, the stress test result information including stability fault results is generated.

8. The method according to claim 7, characterized in that, When the stress test result information includes the stability failure result, the method further includes: The optical zoom motor is calibrated using the cumulative step loss deviation; wherein, when the cumulative step loss deviation is in a first parameter range, the digital zoom parameters of the optical zoom motor are adjusted; and when the cumulative step loss deviation is in a second parameter range, the number of motion steps of the optical zoom motor is corrected according to the cumulative step loss deviation. Get the motion parameters for the current loop; When the detection step size of the motion parameters in the current cycle is reduced to the minimum step size, the duty cycle of the optical zoom motor is adjusted to a stationary state.

9. The method according to claim 1, characterized in that, The method further includes: Record the number of zoom cycles performed by the optical zoom motor per unit time. When the number of zoom cycles reaches a preset feedback threshold, a real-time stress test command is generated. In response to the real-time stress test command, a real-time stress test is performed on the optical zoom motor to obtain the real-time stress test result; The number of motion steps of the optical zoom motor is corrected based on the real-time pressure test results.

10. An automated pressure testing system for the stability of an optical zoom motor, characterized in that, The system includes: The parameter acquisition module is used to acquire stress test parameters, which include test modes and motion parameters corresponding to the test modes; the test modes include at least one of aging test modes and life test modes. The motion control module is used to control the optical zoom motor to perform cyclic test motion according to the pressure test parameters in order to collect pressure test data; the pressure test data includes the actual return position determined by controlling the optical zoom motor to return to the reference positioning point during the execution of the cyclic test motion; the reference positioning point is the high and low level transition point of the voltage sampling of the optical zoom motor; The step loss calculation module is used to calculate core step loss data based on theoretical motion data and the pressure test data; the core step loss data includes motor step loss values ​​calculated by comparing the theoretical reference position in the theoretical motion data with the actual regression position; The result generation module is used to generate stress test result information based on the core step loss data. The stress test result information includes the cumulative step loss deviation of the motor step loss value during multiple cyclic test movements.

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