Multi-channel servo endurance test system
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SGS-CSTC STANDARDS TECH SERVICES LTD
- Filing Date
- 2026-03-31
- Publication Date
- 2026-06-30
Smart Images
Figure CN122308327A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of mechanical component durability testing technology. More specifically, this invention relates to a multi-channel servo durability testing system. Background Technology
[0002] The durability of mechanical components is a core indicator of their reliability. Servo-driven testing equipment, capable of simulating complex working conditions, is widely used for fatigue life verification in fields such as automotive parts and construction machinery. However, existing servo durability testing equipment faces numerous unresolved issues in practical applications, failing to meet the demands for efficient and accurate testing. Most devices only support single-channel or at most two-channel parallel testing. When simultaneous testing of batch components or multi-station assemblies is required, multiple independent devices must be deployed, significantly increasing equipment purchase and site occupancy costs, and also dispersing test data, multiplying the workload for subsequent integration and analysis. The key to this problem lies in the difficulty of controlling signal interference and timing deviations between units during multi-channel control. The existing architecture lacks a stable synchronization mechanism, making it prone to asynchronous actions between channels, resulting in incomparable test data. Summary of the Invention
[0003] One objective of this invention is to provide a multi-channel servo durability testing system. Existing servo durability testing equipment is mostly single-channel or dual-channel, making it difficult to test multiple components simultaneously. Furthermore, it lacks a unified control core, resulting in poor coordination between unit actions. Simultaneously, test data is stored in a scattered manner, real-time monitoring is insufficient, making it impossible to accurately control the testing process. The lack of fully closed-loop control also leads to insufficient testing accuracy. Therefore, there is an urgent need for a system that integrates multi-channel, high-precision control and data management.
[0004] The existing testing system does not conduct a comprehensive check of the safety status of all units before initiating unit actions, which can easily lead to collision failures due to abnormal positions of individual units. Furthermore, after a failure occurs, only a simple alarm is triggered without clear fault location or status indication, requiring staff to investigate one by one, prolonging test interruption time and posing safety hazards and efficiency issues.
[0005] In existing systems, servo drive operating parameters are often adjusted based on single sensor signals without considering signal fluctuations, which can easily lead to erroneous parameter adjustments. Changing parameters when there is a brief signal anomaly can cause unstable test conditions, affecting the accuracy and consistency of test data. Therefore, a parameter adjustment mechanism based on stable signals needs to be established.
[0006] Existing multi-channel signal acquisition modules lack channel self-diagnosis functions. When analog input channels experience disconnections or sensor failures, they cannot be detected in time, leading to the accumulation of invalid test data and even causing system malfunctions due to erroneous signals, thus affecting test reliability. Real-time monitoring of channel status is necessary.
[0007] In multi-channel testing, each servo drive unit relies on its local clock to execute commands, which can easily lead to asynchronous actions due to clock deviations, affecting the accuracy of complex testing procedures. Existing control modes do not incorporate a global clock and compensation mechanism, making it difficult to eliminate coordination errors caused by clock differences; therefore, a synchronous control mode needs to be established.
[0008] In existing master-slave collaborative control, the execution timing is adjusted only based on the clock offset, without considering the communication delay between the master and slave stations. This results in a deviation between the actual execution time of the slave station and the target time. The accumulation of communication delay reduces the synchronization accuracy of multi-axis systems, failing to meet the stringent requirements of high-precision testing for action timing.
[0009] To achieve these objectives and other advantages of the present invention, a multi-channel servo durability testing system is provided, comprising: An industrial computer is used to provide a graphical user interface to receive user commands, set test parameters, display real-time test curves, and store test data. At least two servo drive units, each servo drive unit includes a servo driver, a servo motor driven by the servo driver, and an electric cylinder that converts the rotary motion of the servo motor into linear motion. Each electric cylinder is equipped with a position detection device, which is used to detect the actual linear displacement of the electric cylinder push rod. The signal output terminal of the position detection device is connected to the feedback interface of the corresponding servo driver to form a closed-loop control. A programmable logic controller (PLC) communicates with an industrial computer to receive test procedure programs and parameters, and communicates with all servo drives to send control commands to the servo drives. The multi-channel signal acquisition module provides at least 8 analog input channels and at least 8 digital input channels for connecting external sensors and transmitting the acquired sensor signals to the programmable logic controller for logical judgment. At least one actuator, which is a pneumatic actuator or an electric actuator, has its control terminal connected to the output terminal of a programmable logic controller and is directly driven by the programmable logic controller; The programmable logic controller is configured to perform the following controls by executing a test procedure: sending control commands to each servo driver in a preset order; determining whether the execution conditions of each step in the test procedure are met based on sensor signals obtained from the multi-channel signal acquisition module; and performing subsequent operations when the conditions are met, including sending commands to the next servo driver, adjusting the current servo driver's operating parameters, or controlling the actuator's actions. By repeatedly executing the above process, all servo drive units and actuators are driven to work together in sequence to complete one test cycle; the completed test cycles are counted and repeated until the preset number of cycles is reached.
[0010] Preferably, the programmable logic controller is further configured to perform the following steps: Before driving any servo drive unit or actuator, read the real-time sensor signal collected by the multi-channel signal acquisition module, and determine whether all other servo drive units and actuators have reached the preset safe position or are in the preset safe state that meets the requirements of the test procedure sequence based on the real-time sensor signal. If the result of the judgment is negative, the test process is paused and the industrial control computer is controlled to issue a visual alarm on its graphical user interface. The visual alarm specifically includes: highlighting the servo drive unit or actuator that has not met the safety conditions, and displaying text information indicating its current actual position or status, as well as the expected safe position or expected safe status that it needs to reach.
[0011] Preferably, the test parameters include sensor signal threshold ranges set for steps in the test process related to adjusting the servo drive operating parameters; The programmable logic controller is configured to periodically acquire and compare the real-time sensor signals acquired by the multi-channel signal acquisition module with the sensor signal threshold range at a predetermined sampling period before performing operating parameter adjustments. If the real-time sensor signal is continuously within a preset sensor signal threshold range for a first time period, then the operating parameters of the servo driver are adjusted; otherwise, the current operating parameters of the servo driver are maintained.
[0012] Preferably, the programmable logic controller is also configured to perform the following operations: Record the cumulative number of times the operation parameter adjustment was interrupted due to the real-time sensor signal exceeding the sensor signal threshold range in a single test cycle; When the cumulative number of interruptions exceeds the preset allowable threshold, a diagnostic test sequence independent of the normal endurance test cycle is initiated. The diagnostic test sequence includes the following steps: controlling the relevant servo drive unit and actuator to perform a set of preset benchmark verification actions with a displacement amplitude and movement speed lower than the normal test, while simultaneously monitoring the sensor signal response of the multi-channel signal acquisition module. Based on whether the sensor signal response meets the expected range of normal operation of the test system, a fault tracing prompt is generated and displayed on the graphical operation interface of the industrial control computer. This fault tracing prompt is used to distinguish between the failure of the tested workpiece and the fault of the test system itself.
[0013] Preferably, the multi-channel signal acquisition module further includes a signal self-diagnosis unit, which is configured to perform the following operations: Continuously monitor the signal voltage of each analog input channel; When the signal voltage of any analog input channel exceeds the effective range of the channel in each sampling period of a preset duration, it is determined that the channel has a disconnection or sensor failure. After determining the fault, an alarm signal containing the fault channel identifier is sent to the programmable logic controller. Upon receiving this alarm signal, the programmable logic controller (PLC) pauses the test process and controls the industrial control computer to display the alarm information for the specific faulty channel on the graphical user interface.
[0014] Preferably, the programmable logic controller is configured to operate a master-slave cooperative control mode with clock compensation, which includes: One servo drive unit is designated as the master station, and the remaining servo drive units are designated as slave stations; The master station generates and broadcasts a synchronization control command, which embeds a global timestamp provided by the system's global clock. Each slave station is equipped with a local clock compensation unit. This unit calculates the difference between the received global timestamp and the slave station's local clock, and adjusts the timing of subsequent control commands executed by the slave station based on this difference, so that the actions of all actuators driven by the slave stations are synchronized under a unified global time reference.
[0015] Preferably, the timing of subsequent control commands from the slave station is adjusted based on this difference, specifically including: The clock compensation unit calculates the clock offset; The slave station's motion controller receives the phase motion command embedded with the future target time from the autonomous station, and calculates the future target time by superimposing it with the clock offset and the pre-calibrated fixed communication delay compensation to generate the corrected local execution time. The slave servo driver triggers the actions of its connected actuators based on the local execution time.
[0016] Preferably, the industrial control computer also includes a data comparison and analysis module, which is configured to extract cross-loop datasets of the same specified test step from data files of multiple stored test loops in response to comparison commands input by the user through a graphical user interface. The graphical user interface is configured to provide a trend comparison view, which is configured as follows: A trend curve is generated with the test cycle number as the horizontal axis and the predefined feature parameters extracted from the cross-cycle dataset as the vertical axis. The predefined feature parameters include at least one of the following: peak value, valley value, stable value, overshoot of the motion trajectory, or peak value, mean value, effective value, and range of the sensor signal. Simultaneously, in the trend comparison view, at least two different test cycles selected from the cross-cycle dataset are displayed side-by-side with complete motion trajectory curves or complete sensor signal curves at a specified test step, and the degree of difference between the highlighted complete motion trajectory curves or complete sensor signal curves is calculated.
[0017] The present invention has at least the following beneficial effects: First, this invention enables multi-unit collaborative automated testing, eliminating the need for manual operation of each component sequentially, thus significantly improving testing efficiency. The fully closed-loop control and high-precision signal acquisition of the servo drive unit provide stable load output and reliable data support for durability testing, reducing misjudgments of test results due to data deviations. The centralized industrial control computer interface and data storage function not only reduce the cost of manual intervention but also facilitate the subsequent traceability and organization of test data, adapting to the continuous testing needs of batch workpieces.
[0018] Secondly, the safety verification mechanism of this invention before action execution can avoid motion conflicts between the servo unit and the actuator from the source, effectively reducing equipment wear and workpiece damage caused by mechanical collisions; the rapid alarm response and accurate fault indication allow operators to locate the problematic unit without checking each one individually, shortening fault handling time and reducing the impact of test interruptions on the overall progress; the entire safety control process requires no additional hardware investment, and is only implemented through software logic optimization, which improves test safety and continuity while controlling system upgrade costs.
[0019] Third, the interruption count recording mechanism of this invention provides a quantitative basis for abnormal testing, avoiding the waste of resources caused by blindly starting diagnosis due to occasional interruptions; the reduced motion amplitude and speed in the diagnostic sequence can reduce equipment load while troubleshooting, preventing the fault from expanding; the accurate fault tracing function can quickly distinguish between workpiece and system problems, avoiding misjudging qualified workpieces as defective products, or continuous testing errors caused by failure to repair the system in time, thereby improving the utilization rate of testing resources and the efficiency of system operation and maintenance.
[0020] Fourth, the self-diagnostic function integrated into the acquisition module of this invention can monitor abnormalities in the signal transmission process in real time, promptly detect disconnections or sensor failures, avoid the continuous accumulation of invalid test data, and reduce the workload of subsequent data screening and rejection. Clear fault channel prompts allow maintenance personnel to directly perform targeted inspections, shortening equipment downtime. The self-diagnostic function does not require additional system resources and can operate in parallel with normal signal acquisition, ensuring the reliability and continuity of test data without affecting test efficiency.
[0021] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description
[0022] Figure 1 This is a flowchart of a multi-channel servo durability testing system, one of the technical solutions described in this invention. Detailed Implementation
[0023] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.
[0024] like Figure 1 As shown, according to one embodiment of the present invention, a multi-channel servo durability testing system includes: An industrial computer is used to provide a graphical user interface to receive user commands, set test parameters, display real-time test curves, and store test data. At least two servo drive units, each servo drive unit includes a servo driver, a servo motor driven by the servo driver, and an electric cylinder that converts the rotary motion of the servo motor into linear motion. Each electric cylinder is equipped with a position detection device, which is used to detect the actual linear displacement of the electric cylinder push rod. The signal output terminal of the position detection device is connected to the feedback interface of the corresponding servo driver to form a closed-loop control. A programmable logic controller (PLC) communicates with an industrial computer to receive test procedure programs and parameters, and communicates with all servo drives to send control commands to the servo drives. The multi-channel signal acquisition module provides at least 8 analog input channels and at least 8 digital input channels for connecting external sensors and transmitting the acquired sensor signals to the programmable logic controller for logical judgment. At least one actuator, which is a pneumatic actuator or an electric actuator, has its control terminal connected to the output terminal of a programmable logic controller and is directly driven by the programmable logic controller; The programmable logic controller is configured to perform the following controls by executing a test procedure: sending control commands to each servo driver in a preset order; determining whether the execution conditions of each step in the test procedure are met based on sensor signals obtained from the multi-channel signal acquisition module; and performing subsequent operations when the conditions are met, including sending commands to the next servo driver, adjusting the current servo driver's operating parameters, or controlling the actuator's actions. By repeatedly executing the above process, all servo drive units and actuators are driven to work together in sequence to complete one test cycle; the completed test cycles are counted and repeated until the preset number of cycles is reached. The industrial control computer is equipped with an industrial-grade processor, running a real-time operating system or Windows + real-time kernel; it is equipped with a solid-state drive (SSD) of no less than 256GB for installing the system and applications, and can transmit test data to the data center or local large-capacity storage device in real time through a network interface or additional storage module; the programmable logic controller is a mid-to-high-end modular product that supports multi-axis motion control and high-precision timing processing, and its motion control cycle can be configured to 1ms or lower. Communication with the industrial control computer is achieved via high-speed industrial Ethernet (such as EtherNet / IP, PROFINET) to ensure real-time and reliable transmission of commands and data. Servo drive power can be selected from 0.75kW to 5.5kW, servo motor rated speed range is 100r / min to 3000r / min, and low-speed smooth operation is supported. Electric cylinder stroke can be selected from 50mm to 500mm. The position detection device uses a high-precision optical or magnetic scale, with a signal output frequency not lower than the servo drive position loop sampling frequency requirement, typically reaching 1MHz or higher, to meet the real-time position feedback requirements of the fully closed-loop control. The electric cylinder body can be made of 45# steel, the push rod can be made of 304 stainless steel, and the optical scale housing can be made of aluminum alloy. In the signal acquisition unit, the multi-channel signal acquisition module can provide 8 to 32 channels of analog and digital signals, with analog accuracy reaching ±0.1%FS. For pneumatic actuators, the working pressure can be set from 0.4MPa to 0.8MPa; for electric actuators, the power can be selected from 100W to 500W. The housing of the data acquisition module can be made of aluminum alloy, the internal circuit board can be made of FR-4 epoxy glass cloth substrate, and the cylinder body can be made of aluminum alloy. In terms of assembly location, the industrial computer is installed in the operating area of the test bench at a height of 1.2m to 1.5m; the programmable logic controller and data acquisition module are installed in the electrical control cabinet; the servo drive unit is installed in the load output area; and the actuators are installed as needed next to the fixtures or at the valves. The parameter setting method can be based on the industry standard of the workpiece being tested. For example, the number of test cycles for automotive parts can be set to 1,000 to 100,000, the step judgment interval can be set to 10ms, and the parameter adjustment range can be set to ±5% to ±20%. The working process is as follows: The operator first inputs the test parameters through the industrial control computer interface. The industrial control computer transmits the parameter information to the programmable logic controller (PLC) and stores it. The PLC operates at a high frequency (e.g., 1ms) control cycle, during which it synchronously completes the following: reading sensor signals from the multi-channel signal acquisition module, performing logic and safety judgments, and sending synchronous control commands to each servo driver. At the same time, the industrial control computer acquires data packets from the controller at approximately 10ms intervals for refreshing the interface curve display and storing data. When the signal indicates that the current step condition meets the standard, such as a displacement of 50mm ± 0.05mm, the controller sends a command to the next unit or adjusts the current unit parameters by ±5% to ±20%. If auxiliary actions are required, the actuator is driven to move. After all units complete a complete action in sequence, the controller counts one test cycle. The industrial control computer displays the test curve updated every 100ms and stores the data by timestamp in real time until the preset number of cycles is reached. Functional testing used automotive suspension springs as the experimental subject. The system controlled three servo drive units to synchronously execute 100 reciprocating motion cycles. Measured using a high-precision external timing device, the time synchronization error of the starting point of each channel's action was less than 10μs. The actual positioning accuracy of the electric cylinder, verified using a laser interferometer, showed an error better than ±0.01mm over the entire stroke. The measurement error of the multi-channel signal acquisition module for standard analog input signals was within ±0.1%FS. By adopting this technical solution, the present invention realizes multi-unit collaborative automated testing, eliminating the need for manual operation of each component one by one, thus significantly improving testing efficiency; the servo drive unit's fully closed-loop control and high-precision signal acquisition provide stable load output and reliable data support for durability testing, reducing misjudgments of test results due to data deviation; the centralized industrial control computer operation interface and data storage function not only reduce the cost of manual intervention, but also facilitate the subsequent traceability and organization of test data, adapting to the continuous testing needs of batch workpieces.
[0025] According to another embodiment of the present invention, the programmable logic controller is further configured to perform the following steps: Before driving any servo drive unit or actuator, read the real-time sensor signal collected by the multi-channel signal acquisition module, and determine whether all other servo drive units and actuators have reached the preset safe position or are in the preset safe state that meets the requirements of the test procedure sequence based on the real-time sensor signal. If the result of the judgment is negative, the test process is paused and the industrial control computer is controlled to issue a visual alarm on its graphical user interface. The visual alarm specifically includes: highlighting the servo drive unit or actuator that does not meet the safety conditions, and prompting its current actual position or actual state with text information, as well as the expected safe position or expected safe state that it needs to reach. The threshold for determining the safe position of the servo unit is determined comprehensively based on the mechanical system's clearance, elastic deformation, and detection error. For example, it can be set to ±0.5mm to ±1mm, which is much larger than the system's positioning accuracy (±0.01mm) to ensure reliable judgment of the safe state within the allowable mechanical tolerance and avoid false alarms. The actuator's safe state is judged based on the "on" signal of the magnetic switch, and the verification interval can be set to 10ms. In the visual alarm, the faulty unit is highlighted in red when an alarm occurs, and the prompt text must clearly state the actual and expected states, such as "Servo unit 2 actual position 150.2mm, expected safe position 100.0mm±0.1mm". The programmable logic controller's internal program can be written using ladder diagrams, and the industrial control computer's alarm function can be developed through configuration software scripts without the need for additional hardware. The preset safety position value is determined based on the mechanical limits of the test bench. For example, the initial safety position of the electric cylinder is set to 100.0mm. The text format of the alarm prompt is pre-configured through the industrial control computer software. There are two core indicators: "preset safety position" and "preset safety state." The preset safety position can be divided into three scenarios: first, the zeroing position, where all electric cylinder push rods retract to the mechanical origin before starting a complex motion sequence to avoid interference with the test area; second, the avoidance position, where when servo unit A needs to move in the work area, servo units B and C must move to a pre-planned fixed position that will not collide with A's motion trajectory; and third, the safety distance, referring to the distance between the end of the push rod of any servo unit and the target position. The minimum allowable distance between other units or the workpiece being measured, for example, "the distance between each unit shall not be less than 50mm". The preset safety state, for pneumatic actuators, refers to their "clamped" or "released" state. For example, the servo unit can only start moving when all clamps are in the "released" state to prevent dragging the workpiece and causing damage. For the system itself, this includes system status signals acquired through the digital input channel, such as "servo driver has no alarm", "emergency stop button is not pressed", and "safety door is closed". The threshold for judging the safe position of the servo unit is set to ±0.1mm, and the actuator safety state is judged based on the "on" signal of the magnetic switch, with a check interval set to 10ms. The preset safe position values need to be determined based on the specific scenario. For example, the initial safe position of the electric cylinder is set to the mechanical origin (zero position) of 100.0mm, the avoidance position of unit B when unit A moves is set to 180mm, and the preset safe distance between units is 50mm. The text format of the alarm prompt is pre-configured through the industrial control computer software and must include the fault type and parameter deviation. The working process is as follows: Before sending an action command to any servo drive unit or actuator, the programmable logic controller (PLC) first reads the position feedback signals of all servo units via the communication bus (to determine whether they are in the zeroing / avoidance position and meet the safety distance), and reads the actuator status signals (such as the pneumatic clamp "release" signal) and system status signals (such as the safety door closing signal) via the I / O module; the read signals are compared with the preset safety parameters. The servo unit position must be within ±0.1mm of the preset value, the actuator must provide a magnetic switch "on" signal, the system must have no alarm and the emergency stop must not be triggered; if all units are within the preset value, the system will fail to meet the safety requirements. If all conditions are met, the controller will issue action commands normally. If a non-compliant situation is detected, such as the actual position of servo unit 2 being 150.2mm (exceeding the zero position range of 100.0mm±0.1mm), the test process will be immediately paused, and an alarm command containing faulty unit information will be sent to the industrial control computer. After receiving the command, the industrial control computer will highlight the faulty unit in red on the graphical interface and display the message "Actual position of servo unit 2 is 150.2mm, expected safe position is 100.0mm±0.1mm (zero position)". The entire alarm response time will not exceed 100ms. Functional testing used a test system containing three servo units as the experimental object. The experimental method involved manually setting the position of unit 2 to 150.2mm (the preset safe position is 100.0mm ± 0.1mm), then sending an action command and observing the system's response. Statistical analysis showed that the alarm response time was stable between 50ms and 100ms, and the fault unit identification and prompt information were accurate. By adopting this technical solution, the safety verification mechanism of this invention before action execution can avoid motion conflicts between the servo unit and the actuator from the source, effectively reducing equipment wear and workpiece damage caused by mechanical collisions; the rapid alarm response and accurate fault indication allow operators to locate the problematic unit without checking each one individually, shortening fault handling time and reducing the impact of test interruptions on the overall progress; the entire safety control process requires no additional hardware investment, and is only implemented through software logic optimization, which improves test safety and continuity while controlling system upgrade costs.
[0026] According to another embodiment of the present invention, the test parameters include a range of sensor signal thresholds set for steps in the test process related to the adjustment of servo drive operating parameters; The programmable logic controller is configured to periodically acquire and compare the real-time sensor signals acquired by the multi-channel signal acquisition module with the sensor signal threshold range at a predetermined sampling period before performing operating parameter adjustments. Determine whether the real-time sensor signal is continuously within a preset sensor signal threshold range during a first continuous time period. If so, adjust the operating parameters of the servo driver; otherwise, maintain the current operating parameters of the servo driver. The system includes sensor signal threshold parameter configuration and a parameter adjustment trigger mechanism based on signal stability. In threshold configuration, the range is set according to the sensor type: pressure sensors can be set from 5MPa to 10MPa, temperature sensors from 25℃ to 60℃, and displacement sensors from 50mm to 150mm. In the trigger mechanism, the sampling period of the programmable logic controller (PLC) can be set to 50ms, and the continuous stability judgment time can be set to 500ms. On the device side, threshold parameters are input and stored through an industrial control computer interface, and the trigger logic is implemented through the PLC's timer and comparison instructions. The parameter setting method is to refer to the design working parameters of the workpiece being tested. For example, in pressure control testing, the normal working pressure of the workpiece is 7MPa to 8MPa, and the threshold range is set to 5MPa to 10MPa to reserve fluctuation space. The operating process is as follows: The operator inputs the corresponding threshold range according to the sensor type through the industrial control computer interface: 5MPa to 10MPa for pressure sensors, 25℃ to 60℃ for temperature sensors, and 50mm to 150mm for displacement sensors. These parameters are transmitted from the industrial control computer to the programmable logic controller (PLC) for storage. When the system needs to adjust the servo drive parameters, the controller continuously collects the real-time signals from the corresponding sensors with a 50ms sampling period and compares them with the preset thresholds, while simultaneously starting a timer. If the signal remains within the threshold range for 500ms, such as when the pressure stabilizes at 6MPa, the controller immediately triggers the servo drive parameter adjustment. If the signal exceeds the threshold range midway, such as when the pressure suddenly rises to 11MPa, the controller resets the timer, maintains the current operating parameters of the servo drive, and does not perform any adjustments. Functional testing used pressure sensor signals as the experimental subject. The method involved inputting a signal generator that stabilized at 6 MPa within 500ms and a signal that stabilized at over 10 MPa after 450ms, respectively, and observing whether parameter adjustments were triggered. Statistical analysis showed that the former accurately triggered adjustments, while the latter did not, achieving a 100% trigger accuracy rate. By adopting this technical solution, the present invention provides a judgment standard that fits the actual working conditions for servo parameter adjustment based on the threshold range customized according to the sensor type and workpiece parameters, avoiding adjustment deviations caused by general thresholds; the triggering mechanism based on signal stability can effectively filter out erroneous adjustments caused by instantaneous interference signals, ensuring the stability of the servo drive operating parameters and keeping the test conditions consistent; the stable test environment not only improves the accuracy of single-set test data, but also makes multiple sets of cyclic test data more comparable, providing a more reliable basis for workpiece performance evaluation.
[0027] According to yet another embodiment of the present invention, the programmable logic controller is further configured to perform the following operations: Record the cumulative number of times the operation parameter adjustment was interrupted due to the real-time sensor signal exceeding the sensor signal threshold range in a single test cycle; When the cumulative number of interruptions exceeds the preset allowable threshold, a diagnostic test sequence independent of the normal endurance test cycle is initiated. The diagnostic test sequence includes the following steps: controlling the relevant servo drive unit and actuator to perform a set of preset benchmark verification actions with a displacement amplitude and movement speed lower than the normal test (specifically, it can be set to control the relevant servo drive unit to perform a set of preset benchmark verification actions with a displacement of 20%~30% of the normal test amplitude and a speed of 10%~20% of the normal test speed), and simultaneously monitoring the sensor signal response of the multi-channel signal acquisition module; Based on whether the sensor signal response meets the expected range of normal operation of the test system, a fault tracing prompt is generated and displayed on the graphical operation interface of the industrial control computer. This fault tracing prompt is used to distinguish between the failure of the tested workpiece and the failure of the test system itself. The counting range of the internal counter of the programmable logic controller can be set from 0 to 100 times. In the startup conditions, the interrupt threshold can be set to 5 times. During diagnosis, the servo drive unit operates at 20%~30% of the normal test amplitude and 10%~20% of the normal test speed. The reference verification action can be set to 3 reciprocating extension / retraction movements. In fault diagnosis, the expected range of the sensor signal response is determined based on the system's no-load signal; for example, the no-load response range of the displacement sensor is ±0.02mm. The working process is as follows: After the test begins, the internal counter of the programmable logic controller records in real time the number of times the servo drive parameter adjustment is interrupted due to sensor signal exceeding limits in a single test cycle. The counter automatically increments by 1 each time the interruption occurs. When the cumulative number of interruptions reaches the preset threshold of 5 times, the controller immediately pauses the normal test process and starts the diagnostic test sequence. It sends instructions to the relevant servo units to control them to perform 3 reciprocating extension and retraction benchmark verification actions with a displacement amplitude of 1 / 5 and a movement speed of 1 / 10 of the normal test, while continuously monitoring the sensor signal response. The real-time response signal is compared with the expected range when the system is unloaded (e.g., ±0.02mm for displacement sensor). If it is within the range, the tested workpiece is determined to be faulty. If it exceeds the range, the test system itself is determined to be faulty. The fault type and judgment basis are then sent to the industrial control computer for display in the form of text prompts. The counter is automatically reset to zero after a single test cycle ends. Functional testing used a test system with fault simulation as the experimental object. The experimental method involved simulating five scenarios: signal over-limit interruption, workpiece jamming, and sensor failure. The activation of the diagnostic sequence and fault diagnosis were observed. Statistical analysis showed that the accuracy rate of diagnostic sequence activation was 100%, and the accuracy rate of fault type diagnosis was 100%. By adopting this technical solution, the interruption count recording mechanism of this invention provides a quantitative basis for abnormal testing, avoiding the waste of resources caused by blindly starting diagnosis due to occasional interruptions; the reduced motion amplitude and speed in the diagnostic sequence can reduce equipment load while troubleshooting, preventing the fault from escalating; the accurate fault tracing function can quickly distinguish between workpiece and system problems, avoiding misjudging qualified workpieces as defective products, or continuous testing errors caused by failure to repair the system in a timely manner, thereby improving the utilization rate of testing resources and the efficiency of system operation and maintenance.
[0028] According to another embodiment of the present invention, the multi-channel signal acquisition module further includes a signal self-diagnosis unit, which is configured to perform the following operations: Continuously monitor the signal voltage of each analog input channel; When the signal voltage of any analog input channel exceeds the effective range of the channel in each sampling period of a preset duration, it is determined that the channel has a disconnection or sensor failure. After determining the fault, an alarm signal containing the fault channel identifier is sent to the programmable logic controller. Upon receiving this alarm signal, the programmable logic controller pauses the test process and controls the industrial control computer to display alarm information for the specific faulty channel on the graphical user interface. In the self-diagnostic mechanism, the monitoring cycle for analog channels can be set to 10ms, and the preset duration can be set to 200ms. The effective range of the analog channels, such as 0mA to 20mA, corresponds to a voltage range of 0V to 5V. In alarm control, fault signals are transmitted via digital output, and the alarm information is clearly marked on the industrial control computer interface with the fault channel and problem type. The working process is as follows: After the system starts, the self-diagnostic unit inside the multi-channel signal acquisition module continuously monitors the signal voltage of each analog input channel with a period of 10ms. According to the effective range of the channel configuration (e.g., 0mA to 20mA corresponds to a voltage of 0V to 5V), it determines whether the voltage is within the normal range. When the voltage of a certain channel exceeds the range within 200ms (20 consecutive sampling cycles), such as the voltage of the 0mA to 20mA channel being continuously greater than 5V, the self-diagnostic unit immediately determines that there is a broken wire or sensor failure in that channel, and sends an alarm signal containing the fault channel identifier to the programmable logic controller through the digital output interface. After receiving the alarm signal, the programmable logic controller immediately pauses the current test process and sends an instruction to the industrial control computer, driving the industrial control computer to display specific alarm information such as "Channel 3 has a broken wire or sensor failure, please check" on the graphical operation interface. Functional testing was conducted using channel 3 of the acquisition module. The method involved manually disconnecting the cable of channel 3 and observing the system's alarm response. Statistical analysis showed that the alarm trigger response time was consistently around 200ms, and the fault channel identification was accurate. By adopting this technical solution, the self-diagnostic function integrated into the acquisition module can monitor abnormalities in the signal transmission process in real time, promptly detect disconnections or sensor failures, avoid the continuous accumulation of invalid test data, and reduce the workload of subsequent data screening and rejection. Clear fault channel prompts allow maintenance personnel to directly perform targeted inspections, shortening equipment downtime. The self-diagnostic function does not require additional system resources and can operate in parallel with normal signal acquisition, ensuring the reliability and continuity of test data without affecting test efficiency.
[0029] According to another embodiment of the present invention, the programmable logic controller is configured to operate a master-slave cooperative control mode with clock compensation, the mode comprising: One servo drive unit is designated as the master station, and the remaining servo drive units are designated as slave stations; The master station generates and broadcasts a synchronization control command, which embeds a global timestamp provided by the system's global clock. Each slave station is equipped with a local clock compensation unit. This local clock compensation unit calculates the difference between the received global timestamp and the slave station's local clock, and adjusts the execution timing of subsequent control commands of the slave station based on this difference, so that the actions of all actuators driven by the slave stations are synchronized under a unified global time reference. The global clock accuracy can be set to 1μs, and the timestamp field length of the master station synchronization command can be set to 32 bits. The slave station clock compensation unit is integrated into the servo driver control chip, and the difference calculation period can be set to 100ms. The working process is as follows: After system startup, the programmable logic controller initializes its internal high-precision real-time clock module (1μs accuracy) and sends instructions to each servo drive unit via the EtherCAT bus, designating one as the master station and the rest as slave stations. The master station, based on the system's global clock, broadcasts synchronization messages containing a global timestamp at a fixed, high-frequency communication cycle (e.g., 1ms or lower). Each slave station, upon receiving each synchronization message, instantly calculates the clock offset and dynamically fine-tunes its local clock, thereby achieving continuous microsecond-level synchronization between all slave station clocks and the master station's global clock. Based on this difference, the execution timing of subsequent control instructions is adjusted. For example, if the global timestamp is 100,000μs and the local clock is 99,980μs, the execution time is advanced by 20μs, ensuring that the actuators driven by all slave stations synchronize their actions under a unified global time reference. Functional testing used three servo drive units (1 master and 2 slaves) as the experimental subjects. The experimental method involved controlling the master and slave stations to simultaneously execute the start action, and measuring the timing difference of the actions using a high-precision timer. Statistical analysis showed that the synchronization error between the master and slave stations was controlled within the microsecond range. By adopting this technical solution, the master-slave station configuration and global clock synchronization mechanism of this invention eliminate the action delay caused by the local clock deviation of each servo unit, realize multi-channel microsecond-level synchronization, meet the testing requirements of multi-component collaborative work, and make the test scenario closer to the actual operating state of the workpiece; the high-speed communication capability of the EtherCAT bus ensures the rapid transmission of synchronization commands, and with the clock compensation adjustment of the slave station, the accuracy of action coordination is further improved; the entire synchronization control process is implemented based on the existing hardware upgrade software logic, without the need to replace the high-precision servo unit, thereby improving the test accuracy while reducing the system transformation cost.
[0030] According to another embodiment of the present invention, adjusting the execution timing of subsequent control commands from the slave station based on this difference specifically includes: The clock compensation unit calculates the clock offset; The slave station's motion controller receives the phase motion command embedded with the future target time from the autonomous station, and calculates the future target time by superimposing it with the clock offset and the pre-calibrated fixed communication delay compensation to generate the corrected local execution time. The slave station's servo driver triggers the actions of its connected actuators based on the local execution time; The offset is calculated by averaging five consecutive samples, with each sampling interval set to 20ms. The master station phase motion command includes a delay time relative to the current global time, such as "execute after 1000μs". The pre-calibrated fixed communication delay compensation can be set to 50μs. The communication delay compensation is measured through multiple communication tests, and the average value is stored as a fixed value in the slave station's memory. The working process is as follows: The clock compensation unit of the slave servo drive samples the clock 5 times every 100ms, with each sampling interval of 20ms. The average of the time difference of the 5 samples is taken as the accurate clock offset. When the master station sends a phase motion command with a future target time (such as "execute in 1000μs"), the slave motion controller immediately extracts the target time. The target time is added to the clock offset and the pre-calibrated 50μs fixed communication delay compensation to generate the local execution time. For example, if the target time is 100000μs, the execution time is set to 100070μs. When the slave local clock count reaches the execution time, the servo drive immediately triggers the connected actuator to ensure synchronization with the master station and other slave stations. Functional testing used two slave units as experimental subjects. The experimental method involved measuring the synchronization error of the master and slave units with and without compensation. Statistical analysis showed that the synchronization error after compensation was significantly lower than that without compensation. By adopting this technical solution, the present invention calculates the clock offset by taking the average of multiple samples, which reduces the error of a single sampling and makes the offset calculation more accurate. The integrated clock offset and fixed communication delay correction mechanism comprehensively considers the two types of influencing factors, namely signal transmission and clock difference, further reducing the execution deviation of slave station actions. The improved multi-slave station coordination accuracy can adapt to the multi-dimensional testing requirements of precision components, avoid test data distortion caused by asynchronous actions, and provide reliable timing guarantee for high-requirement durability testing.
[0031] According to another embodiment of the present invention, the industrial control computer further includes a data comparison and analysis module, which is configured to extract cross-cycle datasets of the same specified test step from data files of multiple stored test cycles in response to a comparison command input by the user through a graphical user interface. The graphical user interface is configured to provide a trend comparison view, which is configured as follows: A trend curve is generated with the test cycle number as the horizontal axis and the predefined feature parameters extracted from the cross-cycle dataset as the vertical axis. The predefined feature parameters include at least one of the following: peak value, valley value, stable value, overshoot of the motion trajectory, or peak value, mean value, effective value, and range of the sensor signal. Meanwhile, in the trend comparison view, the complete motion trajectory curves or complete sensor signal curves of at least two different test cycles selected from the cross-cycle dataset are displayed side by side at the specified test step, and the degree of difference between the highlighted complete motion trajectory curves or complete sensor signal curves is calculated. During dataset extraction, 10 to 100 cycles of data can be extracted at a time, with the extraction range set by the user. In the visualization view, the horizontal axis cycle number interval can be set to 10 times. Feature parameters include the peak and trough values of the motion trajectory, and stable values with fluctuations ≤ ±0.05 mm over 100 ms. Differential analysis can employ various algorithms, such as calculating the correlation coefficient or root mean square error (RMSE) between curves. Users can customize differential alarm thresholds in the graphical interface (e.g., setting an alarm when the correlation coefficient is below 0.95), and the system will automatically highlight curve segments with significant differences based on the set threshold. The working process is as follows: After multiple sets of tests are completed, the user inputs a comparison command through the graphical interface of the industrial control computer, specifying the test steps and cycle range to be analyzed (such as "cycles 100 to 200"). The built-in data comparison and analysis module responds to the command, extracts the cross-cycle dataset of the same test step within the corresponding range from the test data file stored in the industrial control computer, automatically extracts the characteristic parameters of each cycle (such as the peak and valley values of the motion trajectory and the stable value with a continuous fluctuation of ≤±0.05mm within 100ms), and generates a trend curve in the trend comparison view with the cycle number as the horizontal axis and the characteristic parameters as the vertical axis. At the same time, the complete trajectory or signal curve of the selected cycle (such as the 100th and 200th cycles) is displayed side by side, and the curve difference is calculated using the correlation coefficient method. When the correlation coefficient is less than 0.9, the difference part is highlighted with a red line and the value is marked. Functional testing used 100 sets of cyclic test data from an automotive shock absorber as the experimental subject. The experimental method involved extracting displacement data from the 50th to 150th cycles for comparative analysis. Statistical analysis showed that the trend curves of the characteristic parameters were clear, and the differences were accurately highlighted. Using this technical solution, the cross-cycle dataset extraction function of this invention supports flexible selection of the analysis range, adapting to the data analysis needs of different testing stages; multi-dimensional visualization transforms abstract data into intuitive curves, making it easy for operators to quickly capture the changing patterns of workpiece performance with the number of cycles; precise difference analysis and highlighting functions can promptly identify the cycle corresponding to data anomalies, providing a basis for judging workpiece performance decay nodes, while reducing the workload and errors of manual data analysis and enhancing the value of mining and utilizing test data.
[0032] System reliability design and engineering implementation considerations To ensure the long-term stable operation of the multi-channel servo durability testing system in an industrial environment, the following key engineering details were considered in the design and implementation: Synchronous control network architecture: To achieve "microsecond-level synchronization" in this application, the system adopts a real-time industrial Ethernet based on EtherCAT as the motion control backbone network. The PLC acts as the EtherCAT master station, and all servo drives act as slave stations connected to the same network segment. The inherent distributed clock mechanism and hardware timestamp function of the EtherCAT protocol provide physical and protocol layer support for the "master-slave cooperative control mode," enabling the master station to deliver globally timestamped instructions to each slave station within tens of microseconds and controlling communication latency jitter at the microsecond level. Safety judgment logic optimization: To avoid the potential logical redundancy caused by "judging all other units" in the claims, in specific implementation, safety judgment is based on the timing relationship diagram of the test process. The PLC internally maintains an action dependency table, only judging whether those preceding or parallel units that might mechanically interfere with the action unit of this step are in a safe position or state in the current step, rather than judging all units. This ensures both safety and improves judgment efficiency. Reasonableness of the diagnostic test sequence: The "displacement amplitude and movement speed below normal test values" in the diagnostic test sequence are specifically defined as follows: the displacement amplitude is set to 20% to 30% of the normal test amplitude, and the movement speed is set to 10% to 20% of the normal test speed. This ratio setting aims to drive the system with low load and low inertia to reproduce basic motion functions, thereby distinguishing between problems caused by workpiece jamming (abnormal load) and problems caused by the system itself (such as guide rail wear, bearing damage, or driver failure). The benchmark verification action consists of three complete low-speed reciprocating movements from the safe position to the test start point. Data storage and indexing: The test data files stored on the industrial control computer adopt a hierarchical index structure: the root directory is "Test Task ID", and the data files are stored in CSV format according to "Cycle Number". Each file contains timestamps, actual positions / speeds / torques of all servo axes, and synchronized data such as all analog / digital channel values. The data comparison and analysis module can quickly locate and extract data within any specified cycle number range through this index structure. The number of devices and processing scale described herein are for the purpose of simplifying the description of the invention. Applications, modifications, and variations of the multi-channel servo durability testing system of this invention will be readily apparent to those skilled in the art.
[0033] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.
Claims
1. A multi-channel servo durability testing system, characterized in that, include: An industrial computer is used to provide a graphical user interface to receive user commands, set test parameters, display real-time test curves, and store test data. At least two servo drive units, each servo drive unit includes a servo driver, a servo motor driven by the servo driver, and an electric cylinder that converts the rotary motion of the servo motor into linear motion. Each electric cylinder is equipped with a position detection device, which is used to detect the actual linear displacement of the electric cylinder push rod. The signal output terminal of the position detection device is connected to the feedback interface of the corresponding servo driver to form a closed-loop control. A programmable logic controller (PLC) communicates with an industrial computer to receive test procedure programs and parameters, and communicates with all servo drives to send control commands to the servo drives. The multi-channel signal acquisition module provides at least 8 analog input channels and at least 8 digital input channels for connecting external sensors and transmitting the acquired sensor signals to the programmable logic controller for logical judgment. At least one actuator, which is a pneumatic actuator or an electric actuator, has its control terminal connected to the output terminal of a programmable logic controller and is directly driven by the programmable logic controller; The programmable logic controller is configured to perform the following controls by executing a test procedure: sending control commands to each servo driver in a preset order; determining whether the execution conditions of each step in the test procedure are met based on sensor signals obtained from the multi-channel signal acquisition module; and performing subsequent operations when the conditions are met, including sending commands to the next servo driver, adjusting the current servo driver's operating parameters, or controlling the actuator's actions. By repeatedly executing the above process, all servo drive units and actuators are driven to work together in sequence to complete one test cycle; the completed test cycles are counted and repeated until the preset number of cycles is reached.
2. The multi-channel servo durability testing system as described in claim 1, characterized in that, The programmable logic controller is also configured to perform the following steps: Before driving any servo drive unit or actuator, read the real-time sensor signal collected by the multi-channel signal acquisition module, and determine whether all other servo drive units and actuators have reached the preset safe position or are in the preset safe state that meets the requirements of the test procedure sequence based on the real-time sensor signal. If the result of the judgment is negative, the test process is paused and the industrial control computer is controlled to issue a visual alarm on its graphical user interface. The visual alarm specifically includes: highlighting the servo drive unit or actuator that has not met the safety conditions, and displaying text information indicating its current actual position or status, as well as the expected safe position or expected safe status that it needs to reach.
3. The multi-channel servo durability testing system as described in claim 2, characterized in that, Test parameters include the range of sensor signal thresholds set for steps in the test process related to adjusting the operating parameters of the servo drive; The programmable logic controller is configured to periodically acquire and compare the real-time sensor signals acquired by the multi-channel signal acquisition module with the sensor signal threshold range at a predetermined sampling period before performing operating parameter adjustments. If the real-time sensor signal is continuously within a preset sensor signal threshold range for a first time period, then the operating parameters of the servo driver are adjusted; otherwise, the current operating parameters of the servo driver are maintained.
4. The multi-channel servo durability testing system as described in claim 3, characterized in that, The programmable logic controller is also configured to perform the following operations: Record the cumulative number of times the operation parameter adjustment was interrupted due to the real-time sensor signal exceeding the sensor signal threshold range in a single test cycle; When the cumulative number of interruptions exceeds the preset allowable threshold, a diagnostic test sequence independent of the normal endurance test cycle is initiated. The diagnostic test sequence includes the following steps: controlling the relevant servo drive unit and actuator to perform a set of preset benchmark verification actions with a displacement amplitude and movement speed lower than the normal test, while simultaneously monitoring the sensor signal response of the multi-channel signal acquisition module. Based on whether the sensor signal response meets the expected range of normal operation of the test system, a fault tracing prompt is generated and displayed on the graphical operation interface of the industrial control computer. This fault tracing prompt is used to distinguish between the failure of the tested workpiece and the fault of the test system itself.
5. The multi-channel servo durability testing system as described in claim 4, characterized in that, The multi-channel signal acquisition module also includes a signal self-diagnosis unit, which is configured to perform the following operations: Continuously monitor the signal voltage of each analog input channel; When the signal voltage of any analog input channel exceeds the effective range of the channel in each sampling period of a preset duration, it is determined that the channel has a disconnection or sensor failure. After determining the fault, an alarm signal containing the fault channel identifier is sent to the programmable logic controller. Upon receiving this alarm signal, the programmable logic controller (PLC) pauses the test process and controls the industrial control computer to display the alarm information for the specific faulty channel on the graphical user interface.
6. The multi-channel servo durability testing system as described in claim 5, characterized in that, The programmable logic controller is configured to operate in a master-slave cooperative control mode with clock compensation, which includes: One servo drive unit is designated as the master station, and the remaining servo drive units are designated as slave stations; The master station generates and broadcasts a synchronization control command, which embeds a global timestamp provided by the system's global clock. Each slave station is equipped with a local clock compensation unit. This unit calculates the difference between the received global timestamp and the slave station's local clock, and adjusts the timing of subsequent control commands executed by the slave station based on this difference, so that the actions of all actuators driven by the slave stations are synchronized under a unified global time reference.
7. The multi-channel servo durability testing system as described in claim 6, characterized in that, Based on this difference, the timing of subsequent control commands executed by the slave station is adjusted, specifically including: The clock compensation unit calculates the clock offset; The slave station's motion controller receives the phase motion command embedded with the future target time from the autonomous station, and calculates the future target time by superimposing it with the clock offset and the pre-calibrated fixed communication delay compensation to generate the corrected local execution time. The slave servo driver triggers the actions of its connected actuators based on the local execution time.
8. The multi-channel servo durability testing system as described in claim 1, characterized in that, The industrial computer also includes a data comparison and analysis module, which is configured to extract cross-cycle datasets of the same specified test step from data files of multiple stored test cycles in response to comparison commands input by the user through a graphical user interface. The graphical user interface is configured to provide a trend comparison view, which is configured as follows: A trend curve is generated with the test cycle number as the horizontal axis and the predefined feature parameters extracted from the cross-cycle dataset as the vertical axis. The predefined feature parameters include at least one of the following: peak value, valley value, stable value, overshoot of the motion trajectory, or peak value, mean value, effective value, and range of the sensor signal. Meanwhile, in the trend comparison view, the complete motion trajectory curves or complete sensor signal curves of at least two different test cycles selected from the cross-cycle dataset are displayed side by side at the specified test step, and the degree of difference between the highlighted complete motion trajectory curves or complete sensor signal curves is calculated.