A light output control method and system based on temperature change prediction

Abstract

The application relates to the technical field of automatic control, and discloses a light output control method and system based on temperature change prediction, which comprises the following steps: acquiring a current temperature value of a controlled object; calculating a temperature change rate according to the current temperature value in a plurality of continuous sampling periods; comparing the temperature change rate with a preset direction determination threshold value, and determining the change direction of the temperature according to the comparison result; generating a prediction adjustment starting signal when the change direction is a first direction and the temperature change rate exceeds a prediction adjustment triggering threshold value, or when the change direction is a second direction and the absolute value of the temperature change rate exceeds the prediction adjustment triggering threshold value; determining a control quantity adjustment coefficient according to the temperature change rate, and calculating a target control quantity value based on the control quantity adjustment coefficient and the current control quantity of the controlled object; and adjusting the control quantity of the controlled object according to the target control quantity value, so as to control the light output value of the controlled object. The application improves the stability of the light output by predicting the control quantity adjustment through the temperature change rate.

Description

Technical Field

[0001] This invention relates to the field of automatic control technology, and specifically to a light output control method and system based on temperature change prediction. Background Technology

[0002] In the fields of industrial automation and process control, the stability of the output of a controlled object is easily affected by internal thermal effects and fluctuations in ambient temperature. Temperature changes alter the physical characteristic parameters of the controlled object, causing the controlled variable of the control system to deviate from the desired value, thus affecting control accuracy and system reliability. To suppress the impact of temperature disturbances on the output, existing control systems typically install temperature sensing elements on the controlled object, using real-time acquisition of the current temperature value to provide feedback adjustment to the control variable.

[0003] The existing technology has the following problems: the adjustment of the control quantity is triggered based on the absolute value of the current temperature, and there is a time lag between the start of temperature change and the triggering of the control action. Under the condition of rapid temperature change, it is difficult to track temperature disturbances in time; after the control quantity is adjusted, the temperature of the controlled object does not respond immediately. The existing method does not model and utilize this lag characteristic, and the adjustment timing does not match the actual thermal response characteristics; the control effect verification depends on the temperature sensor reading, and there is a lack of closed-loop verification of the actual effect of the output quantity, making it difficult to ensure control accuracy. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a light output control method and system based on temperature change prediction, which can effectively solve the problems in the background technology. The specific technical solution of this application is as follows:

[0005] A light output control method based on temperature change prediction, characterized in that it includes:

[0006] Get the current temperature value of the controlled object;

[0007] The rate of temperature change is calculated based on the current temperature value from multiple consecutive sampling periods;

[0008] The temperature change rate is compared with a preset direction determination threshold, and the direction of temperature change is determined based on the comparison result.

[0009] When the direction of change is a first direction and the rate of temperature change exceeds a preset prediction adjustment trigger threshold, or when the direction of change is a second direction and the absolute value of the rate of temperature change exceeds the prediction adjustment trigger threshold, a prediction adjustment start signal is generated.

[0010] After generating the predictive regulation start signal, the control quantity adjustment coefficient is determined according to the temperature change rate, and the target control quantity value is calculated based on the control quantity adjustment coefficient and the current control quantity of the controlled object.

[0011] Adjust the control quantity of the controlled object according to the target control quantity value to control the light output value of the controlled object.

[0012] Specifically, calculating the temperature change rate based on the current temperature value from multiple consecutive sampling periods includes:

[0013] Obtain the temperature values ​​for N consecutive sampling periods, where N is a positive integer greater than or equal to 3;

[0014] The linear trend of the temperature value is determined based on the temperature value of the N consecutive sampling periods, and the slope of the temperature value changing with time is obtained.

[0015] The slope is used as the rate of temperature change.

[0016] Specifically, the direction determination threshold includes a first direction determination threshold and a second direction determination threshold, wherein the first direction determination threshold is a positive value and the second direction determination threshold is a negative value; the change direction includes a first direction, a second direction, and a third direction, wherein the first direction is opposite to the second direction, and the third direction corresponds to the direction where the temperature change rate is between the second direction determination threshold and the first direction determination threshold; the step of comparing the temperature change rate with a preset direction determination threshold and determining the temperature change direction based on the comparison result includes:

[0017] When the rate of temperature change is greater than the first direction determination threshold, the direction of change is determined to be the first direction;

[0018] When the rate of temperature change is less than the second direction determination threshold, the direction of change is determined to be the second direction;

[0019] When the rate of temperature change is greater than or equal to the second direction determination threshold and less than or equal to the first direction determination threshold, the direction of change is determined to be the third direction.

[0020] Specifically, determining the control quantity adjustment coefficient based on the temperature change rate includes:

[0021] Acquire historical temperature change data and historical control quantity adjustment data of the controlled object;

[0022] Extract the control quantity values ​​before and after each control quantity adjustment from the historical control quantity adjustment data, and extract the temperature change rate sequence before and after each control quantity adjustment from the historical temperature change data;

[0023] For each control quantity adjustment, the lag time corresponding to the start of a stable response of the temperature change rate after the control quantity adjustment is determined according to the temperature change rate sequence, and the lag time, the temperature change rate before adjustment, the change in temperature change rate after adjustment, and the control quantity adjustment amount are used together to form a response sample.

[0024] The current temperature range is determined based on the current temperature value, the current control range is determined based on the current control quantity, and the current direction of change is determined based on the temperature change rate.

[0025] Select response samples from the response samples that match the current temperature range, the current control range, and the current direction of change, and generate the temperature response relationship under the current operating condition based on the selected response samples;

[0026] The control quantity adjustment coefficient is determined based on the temperature change rate and the temperature response relationship under the current operating conditions.

[0027] Specifically, determining the control quantity adjustment coefficient based on the temperature change rate and the temperature response relationship under the current operating condition includes:

[0028] The average value of the hysteresis time in the response samples is taken as the hysteresis hold period, which is used to characterize the delay duration from the start of control quantity adjustment to the start of temperature change rate response;

[0029] Starting from the control quantity adjustment time, the prediction time axis is divided into a lag hold period and a response activation period according to the lag hold period.

[0030] During the hysteresis hold period, the predicted temperature change rate continues according to the current temperature change rate.

[0031] Within the effective response period, the predicted temperature change rate is corrected based on the temperature response relationship under the current operating condition.

[0032] The control quantity adjustment coefficient is determined based on the comparison between the corrected predicted temperature change rate within the effective response segment and the preset target temperature change rate.

[0033] Specifically, it also includes:

[0034] After adjusting the control quantity, the current control quantity value and current temperature value of the controlled object are obtained;

[0035] Based on the current control value and the current temperature value, the current light output value of the controlled object is determined through a preset mapping relationship between the control value, temperature and light output.

[0036] Obtain the preset target light output value;

[0037] The current light output value is compared with the target light output value, and the adjustment effect of the control quantity is verified based on the comparison result.

[0038] Specifically, the mapping relationship is established as follows:

[0039] During the calibration phase before the controlled object leaves the factory, the control quantity value and ambient temperature value of the controlled object are adjusted with a preset step size, and the light output value under each combination is measured.

[0040] The measured control value, temperature value, and light output value are fitted to establish a correspondence between them, which serves as the mapping relationship.

[0041] Specifically, verifying the adjustment effect of the control quantity based on the comparison result includes:

[0042] Calculate the deviation between the current light output value and the target light output value;

[0043] When the deviation value exceeds the preset deviation threshold, it is determined that the adjustment effect has not met the standard, and a closed-loop correction signal is generated.

[0044] After generating the closed-loop correction signal, the closed-loop correction amount is determined based on the deviation value, and the control quantity is adjusted again based on the closed-loop correction amount.

[0045] After readjusting the control quantity, the current light output value of the controlled object is re-determined and compared with the target light output value. If the deviation value still exceeds the preset deviation threshold, the steps of generating a closed-loop correction signal and readjusting the control quantity are repeated until the deviation value does not exceed the preset deviation threshold or the number of repetitions reaches the preset maximum number of repetitions.

[0046] Specifically, adjusting the control quantity of the controlled object according to the target control quantity value includes:

[0047] The control quantity of the controlled object is adjusted from its current value to the target control quantity value, and the rate of change of the control quantity during the adjustment process does not exceed the preset maximum rate of change.

[0048] A light output control system based on temperature change prediction, used to implement the aforementioned light output control method based on temperature change prediction, includes:

[0049] The temperature acquisition module obtains the current temperature value of the controlled object;

[0050] The rate of change calculation module calculates the temperature change rate based on the current temperature value over multiple consecutive sampling periods;

[0051] The direction determination module compares the temperature change rate with a preset direction determination threshold and determines the direction of temperature change based on the comparison result. When the direction of change is a first direction and the temperature change rate exceeds a preset prediction adjustment trigger threshold, or when the direction of change is a second direction and the absolute value of the temperature change rate exceeds the preset prediction adjustment trigger threshold, a prediction adjustment start signal is generated. When the direction of change is a third direction, no prediction adjustment start signal is generated.

[0052] The control quantity adjustment module, after generating the predictive adjustment start signal, determines the control quantity adjustment coefficient based on the temperature change rate, calculates the target control quantity value based on the control quantity adjustment coefficient and the current control quantity of the controlled object, and adjusts the control quantity of the controlled object according to the target control quantity value to control the light output value of the controlled object;

[0053] The light output verification module, after executing the adjustment of the control quantity, obtains the current control quantity value and the current temperature value of the controlled object. Based on the current control quantity value and the current temperature value, and through a preset mapping relationship between the control quantity, temperature and light output, it determines the current light output value of the controlled object. The current light output value is compared with a preset target light output value, and the adjustment effect of the control quantity is verified based on the comparison result.

[0054] The beneficial effects of this invention are as follows: By calculating the rate of temperature change and combining it with the trend of change to trigger predictive adjustment in advance, the control action is initiated before the light output deviation is caused by temperature disturbance. Compared with the traditional method based on absolute temperature control, this reduces the impact of response lag. By distinguishing between heating and cooling conditions and triggering adjustment separately, it helps to reduce false triggering and missed triggering caused by indiscriminate response. The adjustment range of the control quantity is dynamically determined according to the rate of temperature change, which helps to reduce over-adjustment or under-adjustment caused by fixed step size adjustment. The above mechanisms work together to match the timing, direction, and amplitude of adjustment with the temperature change law, improving the stability of light output under temperature disturbance. By extracting the lag time and combining it with the condition matching to construct the temperature response relationship, the prediction time axis is divided into a lag holding segment and a response effective segment for segmented prediction, which adapts to the thermal response lag characteristics and helps to reduce light output fluctuations caused by premature or excessively large control quantity adjustments. The real-time light output is estimated based on the mapping relationship, and closed-loop comparison and iterative correction are performed with the target value to form a closed-loop control link, which helps to improve the control accuracy of light output. Attached Figure Description

[0055] Figure 1 This is a schematic flowchart of a light output control method based on temperature change prediction in an embodiment of the present invention.

[0056] Figure 2This is a schematic diagram of the process for determining the direction of temperature change and triggering the predicted adjustment in a light output control method based on temperature change prediction in an embodiment of the present invention.

[0057] Figure 3 This is a schematic diagram of the gradual adjustment of the control quantity in a light output control method based on temperature change prediction in an embodiment of the present invention.

[0058] Figure 4 This is a structural block diagram of a light output control system based on temperature change prediction in an embodiment of the present invention. Detailed Implementation

[0059] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0060] In embodiments of the present invention, the terms "exemplarily" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplarily" or "for example" in embodiments of the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the terms "exemplarily" or "for example" is intended to present the relevant concepts in a specific manner.

[0061] Hereinafter, the terms "first," "second," and other generic terms are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of the present invention, unless otherwise stated, "a plurality of" means two or more.

[0062] Figure 1 A specific embodiment of the light output control method based on temperature change prediction according to the present invention includes:

[0063] S101. Obtain the current temperature value of the controlled object;

[0064] S102. Calculate the temperature change rate based on the current temperature value from multiple consecutive sampling periods;

[0065] S103. Compare the temperature change rate with a preset direction determination threshold, and determine the direction of temperature change based on the comparison result;

[0066] S104. When the direction of change is a first direction and the rate of temperature change exceeds a preset prediction adjustment trigger threshold, or when the direction of change is a second direction and the absolute value of the rate of temperature change exceeds the prediction adjustment trigger threshold, a prediction adjustment start signal is generated.

[0067] S105. After generating the predictive adjustment start signal, determine the control quantity adjustment coefficient according to the temperature change rate, and calculate the target control quantity value based on the control quantity adjustment coefficient and the current control quantity of the controlled object.

[0068] S106. Adjust the control quantity of the controlled object according to the target control quantity value to control the light output value of the controlled object.

[0069] Traditional control methods rely on the absolute value of the current temperature for temperature compensation triggering. The system only begins to respond after detecting that the temperature has reached a preset temperature trigger threshold. Temperature change is a continuous process, and there is a time delay between the start of the temperature change and the reaching of the temperature trigger threshold. Existing control methods lack a mechanism to predict the temperature change trend during this delay, resulting in a lag in control response and potential fluctuations in light output.

[0070] In this embodiment, the temperature value of the controlled object is continuously acquired at a preset sampling period. The sampling period is set according to the system's real-time requirements and the rate of temperature change. The response time of the temperature sensor is no greater than 20ms, the sampling rate of the analog-to-digital converter is no less than 2000 times per second, and the system control cycle is 10ms. Considering the above hardware parameters and system real-time requirements, the sampling period is set to 100ms, which is 10 times the system control cycle. This ensures that multiple hardware samples are completed and averaged within each sampling period to suppress measurement noise, while avoiding excessive processor resource consumption due to overly frequent sampling. The sampling period is generally adjusted within the range of 50ms to 500ms based on the response characteristics of the temperature sensor in the actual application. A sampling period that is too short will increase system overhead, while a sampling period that is too long may miss details of temperature changes. For example, the sampling period in this embodiment is set to 100ms. Temperature acquisition obtains the current temperature value of the controlled object through a temperature sensor, and the temperature value is expressed in °C. The temperature sensor can be a negative temperature coefficient thermistor or an integrated temperature sensing chip. The resistance of a negative temperature coefficient thermistor decreases as temperature increases. A voltage divider circuit and an analog-to-digital converter convert this resistance change into a digital temperature value. The temperature measurement accuracy is better than ±1℃. The analog voltage signal output by the temperature sensor is then converted into a digital temperature value for subsequent processing.

[0071] Specifically, while collecting temperature values, the sampling time for each temperature value is also recorded, forming a time-temperature data sequence that provides a time reference for subsequent calculations of the temperature change rate. The temperature data sequence is stored in memory as a circular queue, retaining data from the most recent 100 sampling points. The temperature data sequence is arranged in chronological order of sampling time, with each data item containing the sampling time and the corresponding temperature value. When new temperature data is generated, it is added to the tail of the queue; when the queue length exceeds 100 data items, the data at the head of the queue is automatically removed.

[0072] Furthermore, temperature values ​​for N consecutive sampling periods are obtained, where N is a positive integer greater than or equal to 3. The value of N determines the calculation period for the temperature change rate, which is equal to N multiplied by the sampling period. A shorter calculation period results in a faster response, but fewer data points are involved in the fitting, leading to weaker noise immunity. The value of N is determined based on the thermal time constant of the controlled object, which is measured through a step response experiment. A step change in control quantity is applied to the controlled object, and the response curve of temperature change over time is recorded. The time required for the temperature change to reach 63.2% of the steady-state change is the thermal time constant. Experimental measurements show that the thermal time constant of the controlled object is in the range of 1 to 5 seconds. Considering both the thermal time constant of the controlled object and the system control period of 10 ms, a calculation period of 1 second balances response speed and noise immunity; therefore, N equals 1 second divided by 100 ms, resulting in a value of 10. The number of sampling periods, N, should not be too small, otherwise the noise at a single sampling point will have a significant impact on the calculation of the rate of change; nor should it be too large, otherwise the rate of change will lag behind the actual temperature change. N can be adjusted within the range of 3 to 50 according to the thermal time constant of the controlled object and the sampling period.

[0073] In this embodiment, the linear trend of temperature change is determined based on the temperature values ​​over N consecutive sampling periods, resulting in the slope of the temperature change over time. This slope is then used as the rate of temperature change. The rate of temperature change is calculated using a least squares method for linear fitting. Specifically, the sampling period number i is used as the independent variable, where i equals 1, 2, 3, up to N, and the corresponding temperature value... The dependent variable is represented by the fitted straight line expression:

[0074]

[0075] in, Let be the temperature value in the i-th sampling period, where i is the sampling period number, k is the slope of the fitted line, and b is the intercept of the fitted line. The formula for calculating the slope k of the fitted line is:

[0076]

[0077] The meanings of each symbol are as follows: N is the total number of sampling periods involved in the calculation; i is the sampling period number, which increases sequentially from 1 to N; The temperature value collected in the i-th sampling period is expressed in °C. The calculated slope k is taken as the rate of temperature change, with the unit being °C / s. A positive value of k indicates that the temperature is rising, while a negative value indicates that the temperature is falling. The absolute value of k indicates the rate of temperature change.

[0078] For example, if the temperature values ​​corresponding to the 10 sampling periods are 25.1℃, 25.3℃, 25.5℃, 25.7℃, 25.9℃, 26.1℃, 26.3℃, 26.5℃, 26.7℃, and 26.9℃ respectively, then the fitted slope k is 2.0℃ / s, indicating that the temperature rises at a rate of 2.0℃ / s.

[0079] It should be noted that the linear fitting method fully utilizes temperature data from multiple sampling points, effectively suppressing the impact of single-point noise on the calculation of the rate of change. If an outlier occurs during the calculation of the temperature rate of change, the system removes the outlier and replaces it with a linear interpolation of the adjacent normal temperature value, then recalculates the temperature rate of change. The outlier determination method is as follows: calculate the difference between the current temperature value and the temperature value of the previous sampling period. If this difference exceeds the preset outlier determination threshold, the current temperature value is determined to be an outlier. The setting of the outlier determination threshold needs to comprehensively consider the measurement accuracy of the temperature sensor and the normal operating temperature change rate of the controlled object. The maximum normal operating temperature change rate of the controlled object is determined as follows: under rated operating conditions, drive the controlled object at the maximum control variable change rate, record the temperature change curve, and take the maximum value of the temperature change rate in the curve as the normal maximum change rate. According to actual measurements, the temperature change of the controlled object in adjacent sampling periods under normal operating conditions does not exceed 3℃ / s. The anomaly detection threshold is set at 10℃, which is calculated by multiplying the normal maximum temperature change rate of 3℃ / s by the sampling period of 100ms (0.3℃) by 33 times and then rounding down. This threshold is sufficiently large to avoid misjudging normal temperature fluctuations as anomalies, while effectively identifying temperature jumps caused by poor sensor contact or electromagnetic interference. The anomaly detection threshold is generally adjusted within the range of 5℃ to 15℃ based on the measurement accuracy of the temperature sensor and the normal temperature change rate of the controlled object.

[0080] Figure 2 This is a schematic diagram of the process for determining the direction of temperature change and triggering the predicted adjustment in a light output control method based on temperature change prediction according to the present invention. Figure 2This demonstrates the complete decision-making process from temperature change rate input to predictive regulation start signal output. Specifically, the temperature change rate calculated from the change rate is received and compared with a first direction determination threshold and a second direction determination threshold. When the temperature change rate is greater than the first direction determination threshold, the change direction is determined to be the first direction, i.e., temperature rising; when the temperature change rate is less than the second direction determination threshold, the change direction is determined to be the second direction, i.e., temperature falling; when the temperature change rate is between the first and second direction determination thresholds, the change direction is determined to be the third direction, i.e., temperature stabilization. If determined to be the first direction, the process continues to determine whether the temperature change rate is greater than the predictive regulation trigger threshold; if it is, a predictive regulation start signal is generated. If determined to be the second direction, the process continues to determine whether the absolute value of the temperature change rate is greater than the predictive regulation trigger threshold; if it is, a predictive regulation start signal is generated. If determined to be the third direction or not exceeding the predictive regulation trigger threshold, no predictive regulation start signal is generated, and the process returns to monitoring the temperature change rate.

[0081] Specifically, a first direction determination threshold and a second direction determination threshold are preset before direction determination. The first direction determination threshold is a positive value, and the second direction determination threshold is a negative value. The magnitude of the direction determination threshold determines the sensitivity of temperature change direction determination. The direction determination threshold is set based on the following: within the rated operating temperature range of the controlled object, when the temperature change rate is lower than the threshold, the impact of the temperature change on the light output is less than 1 / 3 of the light output control accuracy, and no trigger adjustment is required; when the temperature change rate is higher than the threshold, the impact of the temperature change on the light output exceeds the control accuracy requirement, and trigger adjustment is required. Calibration experiments have determined that the light output control accuracy requirement is ±3%. When the temperature change rate is lower than 0.5℃ / s, the light output drift caused by the temperature change is less than 1%, and no adjustment is required; when the temperature change rate is higher than 0.5℃ / s, the light output drift exceeds 3%, and trigger adjustment is required. Therefore, the first direction determination threshold is set to 0.5℃ / s, and the second direction determination threshold is set to -0.5℃ / s. The direction determination threshold is set within the range of 0.2℃ / s to 1.0℃ / s based on the light output temperature characteristics of the controlled object and the control accuracy requirements. For every 1% change in the light output temperature characteristics, the threshold is shifted proportionally by 0.1℃ / s, and for every 1% increase in control accuracy requirements, the threshold is decreased by 0.05℃ / s.

[0082] In this embodiment, the temperature change rate k is compared with a first direction determination threshold and a second direction determination threshold, and the direction of temperature change is determined based on the comparison result. When the temperature change rate k is greater than the first direction determination threshold, i.e., k is greater than 0.5℃ / s, it is determined that the temperature is rising. When the temperature change rate k is less than the second direction determination threshold, i.e., k is less than -0.5℃ / s, it is determined that the temperature is falling. When the temperature change rate k is between the first direction determination threshold and the second direction determination threshold, i.e., -0.5℃ / s is less than or equal to k and k is less than or equal to 0.5℃ / s, the direction of change is determined to be stable temperature, and no adjustment action is triggered at this time.

[0083] Specifically, the predictive adjustment trigger threshold is a positive number used to determine whether the drastic temperature change has reached a level requiring predictive adjustment. A threshold that is too small will lead to frequent and unnecessary adjustments, while a threshold that is too large will delay control timing. The predictive adjustment trigger threshold is set based on the following: when the temperature change rate corresponding to this threshold changes continuously, the time from the current moment until the temperature change causes the light output to exceed the allowable deviation range should be greater than the shortest time required for the control variable to adjust from its current value to the target value, ensuring that adjustment is completed before the light output exceeds the tolerance. Calculations show that the shortest response time for control variable adjustment is 0.5s. When the temperature change rate is 2.0℃ / s, a 1.0℃ temperature change within 0.5s corresponds to a 3% light output drift, which precisely reaches the control accuracy boundary. Therefore, the predictive adjustment trigger threshold is set to 2.0℃ / s. The predictive adjustment trigger threshold is set within the range of 1.0℃ / s to 3.0℃ / s based on the thermal time constant of the controlled object and the system response speed requirements; for every 1s increase in the thermal time constant, the threshold increases by 0.3℃ / s; for every 10% increase in the system response speed, the threshold decreases by 0.2℃ / s.

[0084] Furthermore, after determining the direction of change, the temperature change rate is compared with the predictive regulation trigger threshold. When the direction of change is the first direction and the temperature change rate k is greater than the predictive regulation trigger threshold (i.e., k is greater than 2.0℃ / s), it indicates that the temperature is rising rapidly, requiring predictive regulation to be activated to reduce the control input and prevent overheating of the controlled object or accelerated output decay, thus generating a predictive regulation activation signal. When the direction of change is the second direction and the absolute value of the temperature change rate is greater than the predictive regulation trigger threshold (i.e., the absolute value of k is greater than 2.0℃ / s), it indicates that the temperature is falling rapidly, requiring predictive regulation to increase the control input and prevent insufficient output, also generating a predictive regulation activation signal.

[0085] For example, if the temperature change rate k is equal to 3.5℃ / s, which is greater than the predictive regulation trigger threshold of 2.0℃ / s, and the direction is the first direction, then a predictive regulation start signal is generated immediately. If the temperature change rate k is equal to -4.2℃ / s, and its absolute value is 4.2℃ / s, which is greater than the predictive regulation trigger threshold of 2.0℃ / s, and the direction is the second direction, then a predictive regulation start signal is also generated.

[0086] It should be noted that a temperature change rate exceeding the predictive regulation trigger threshold means that the rate of temperature change is fast enough, indicating that the temperature is in a state of drastic change and immediate control intervention is required. Conversely, if the temperature change rate is in the first or second direction but the rate is slower, i.e., does not exceed the predictive regulation trigger threshold, it indicates that the temperature change is gradual, and the system will not initiate predictive regulation to avoid unnecessary disturbance to the controlled object caused by frequent adjustments.

[0087] Furthermore, upon receiving the predictive regulation initiation signal, the system first acquires historical temperature change data and historical control variable adjustment data for the controlled object. The historical temperature change data records the value of each temperature change rate and its corresponding temperature change trajectory. The historical control variable adjustment data records the magnitude of each control variable adjustment, the adjustment time, and the temperature change after adjustment. This data is stored in the system's non-volatile memory and organized in a time-series manner.

[0088] Specifically, the temperature response relationship of the controlled object is determined based on historical temperature change data and historical control quantity adjustment data. The temperature response relationship characterizes the impact of changes in the control quantity on the rate of temperature change of the controlled object. Specifically, the temperature response relationship describes how much the rate of temperature change will change when the control quantity changes by one unit.

[0089] More specifically, the control values ​​before and after each control adjustment are extracted from historical control adjustment data, and the temperature change rate sequence before and after each control adjustment is extracted from historical temperature change data. For each control adjustment, the lag time corresponding to the start of a stable response in the temperature change rate after the adjustment is determined based on the temperature change rate sequence. The lag time is determined as follows: starting from the control adjustment time, the temperature change rate is monitored. When the change in the temperature change rate in the same direction for three consecutive sampling periods exceeds a preset stable response threshold, the time difference between that time and the adjustment time is taken as the lag time. The stable response threshold is set based on the fact that it should be greater than the peak value of the temperature measurement noise to ensure that the measurement noise is not misjudged as a stable response; at the same time, it should be less than the thermal response amplitude of the controlled object to the minimum effective control adjustment to ensure that the temperature change caused by the control adjustment can be effectively captured. It was measured that the peak-to-peak value of the temperature measurement noise is 0.03℃ / s, and the thermal response amplitude of the controlled object to the minimum control adjustment step size (1% of the rated control value) is 0.15℃ / s. Taking all factors into consideration, a stable response threshold of 0.1℃ / s is chosen, which falls between the noise peak value and the minimum effective response amplitude, and can reliably distinguish between noise and effective response.

[0090] The response sample is composed of the lag time, the rate of temperature change before adjustment, the change in the rate of temperature change after adjustment, and the adjustment amount of the control variable. The format of the response sample is as follows:

[0091]

[0092] in, The lag time after the j-th control adjustment is in seconds. The temperature change rate before adjustment is expressed in °C / s. The change in the rate of temperature change after adjustment is the difference between the rate of temperature change before adjustment and the rate of temperature change after adjustment, and the unit is ℃ / s; The adjustment amount is the control quantity after adjustment, which is the control quantity value after adjustment minus the control quantity value before adjustment.

[0093] The current temperature range is determined based on the current temperature value. The temperature range is divided into multiple continuous intervals according to a preset step size. The step size is set to be smaller than the temperature interval at which the temperature characteristics of the controlled object change significantly, while ensuring that the number of response samples collected in each temperature interval is no less than 20 to meet the statistical requirements of regression analysis. Temperature characteristic scanning experiments on the controlled object show that within a 5℃ temperature interval, the change in the temperature response coefficient is less than 10%, which can be considered as basically consistent temperature characteristics; when the temperature interval exceeds 10℃, the change in the temperature response coefficient exceeds 30%, indicating a significant change in temperature characteristics. Considering both sample size and characteristic consistency, a step size of 5℃ is chosen. The step size is set within the range of 2℃ to 10℃ based on the temperature characteristics of the controlled object and the sample size; for every doubling of the rate of change of temperature characteristics, the step size decreases by 2℃; when the number of samples in the current temperature interval is less than 20, the step size increases by 1℃ until the sample size meets the requirements.

[0094] For example, 20 to 25℃ is one interval, and 25 to 30℃ is the next interval. The current control quantity interval is determined based on the current control quantity. Dividing the control quantity interval involves dividing the control quantity range into multiple consecutive intervals according to a preset step size. The step size should be smaller than the control quantity interval where the temperature characteristic of the controlled object changes significantly, while ensuring that at least 20 response samples are collected within each control quantity interval. After conducting a control quantity scanning experiment on the controlled object, within a control quantity interval of 5% of the rated control quantity, the change in the temperature response coefficient is less than 8%, which can be considered as basically consistent control quantity characteristics; when the control quantity interval exceeds 10% of the rated control quantity, the change in the temperature response coefficient exceeds 25%, and the characteristics change significantly. The step size is set to 5% of the rated control quantity. The step size is generally adjusted within the range of 2% to 10% of the rated control quantity according to the control quantity characteristics of the controlled object and the number of samples. The current direction of change is determined based on the temperature change rate, including a first direction and a second direction.

[0095] Response samples matching the current temperature range, current control variable range, and current direction of change are selected from the response samples. The matching criteria are: the temperature value before adjustment in the response sample falls within the current temperature range; the control variable value before adjustment falls within the current control variable range; and the direction of the temperature change rate before adjustment is consistent with the current direction of change. The temperature response relationship under the current operating condition is generated based on the selected response samples. Specifically, linear regression is performed on the control variable adjustment and the temperature change rate change in the selected response samples to obtain the temperature response coefficient m, i.e. This coefficient reflects the actual impact of changes in the control quantity on the rate of temperature change within the current temperature range, the current control quantity range, and the current direction of change.

[0096] It should be noted that by introducing the extraction of lag time, the incorrect attribution of temperature changes that have not yet produced a response after the control variable adjustment to the current adjustment is avoided. By incorporating lag time into the response samples, the established response relationship more accurately reflects the actual thermal response characteristics of the controlled object. Through triple-condition matching and screening of temperature range, control variable range, and direction of change, samples with different thermal response characteristics under different temperature ranges or control variable levels are avoided from being mixed into the same regression model, making the establishment of the temperature response relationship more accurate. When the number of matched response samples is insufficient, for example, less than 20 groups, the system automatically expands the current temperature range to adjacent ranges or reduces the precision of the control variable range division until the number of matched samples meets the statistical requirements of the regression analysis. After the linear regression is completed, the goodness-of-fit coefficient is calculated. When the goodness-of-fit coefficient is greater than 0.7, the regression result is considered valid, and the temperature response relationship is reliable. When the goodness-of-fit coefficient is less than or equal to 0.7, it indicates that the linear correlation of the matched samples is insufficient, and the system does not update the temperature response relationship, but uses the previously valid temperature response relationship. The goodness-of-fit threshold is set at 0.7 because in system identification within the field of automatic control, a goodness-of-fit coefficient greater than 0.7 indicates that the regression model can explain more than 70% of the variation in the dependent variable, demonstrating good fitting accuracy and predictive ability. When the accumulated sample points exceed 100, the earliest sample points are eliminated according to the first-in, first-out principle, ensuring that the temperature response relationship can track the characteristic changes caused by the aging of the controlled object.

[0097] Furthermore, the control adjustment coefficient is determined based on the current temperature change rate and the temperature response relationship under the current operating conditions. Specifically, the temperature change trajectory of the controlled object is predicted based on the temperature change rate and temperature response relationship, under a preset adjustment amount. In this embodiment, the temperature change trajectory refers to the curve of the temperature change rate over time. Since the control objective is to reduce the current temperature change rate to near the target value, the target temperature change trajectory is simplified to the target temperature change rate, i.e., using 0℃ / s as the control objective to make the temperature change rate approach zero. In practical implementation, the temperature change rate is not required to be strictly equal to 0℃ / s; it only needs to fall within an acceptable temperature change rate range.

[0098] More specifically, the hysteresis hold-up period is first determined based on the hysteresis times in the response samples. The hysteresis hold-up period characterizes the duration of delay between the start of control variable adjustment and the start of the temperature change rate response. The hysteresis hold-up period is determined by averaging the hysteresis times in the matched response samples as the hysteresis hold-up period under the current operating condition.

[0099] Starting from the control adjustment time, the prediction time axis is divided into a lag hold period and a response activation period based on the lag hold time. Within the lag hold period, from the control adjustment time to the end of the lag hold time, the predicted temperature change rate continues according to the current temperature change rate k. Within the response activation period, after the lag hold period ends, the predicted temperature change rate is corrected based on the temperature response relationship under the current operating conditions. Specifically, assuming a proposed control adjustment amount... The change in the rate of temperature change under this adjustment is predicted using the temperature response relationship. During the effective period of the response, the predicted temperature change rate is... .

[0100] Based on the corrected predicted temperature change rate within the effective response segment The control adjustment coefficient is determined by comparing the predicted temperature change rate with the preset target temperature change rate. The target temperature change rate is set to 0℃ / s. When the temperature change rate is 0, it indicates that the temperature is in a stable state and no longer causes continuous temperature drift affecting the light output; this is the ideal control target state. In actual control, the temperature change rate is not required to be strictly equal to 0℃ / s; it only needs to fall within an acceptable temperature change rate range. The predicted temperature change rate will be... Compared to an acceptable temperature change rate range, exemplarily defined as -0.5℃ / s to 0.5℃ / s, at a temperature change rate of 0.5℃ / s, a sustained 0.5℃ temperature change over 1 second corresponds to a 1.5% optical output drift, which is less than half of the optical output control accuracy requirement (±3%), leaving sufficient control margin. Therefore, when the temperature change rate falls within this range, the temperature can be considered to be in a controllable quasi-steady state, requiring no further adjustment. The proposed control variable is iteratively adjusted until the predicted temperature change rate is reached. The temperature change rate falls within the acceptable temperature change rate range. Iterative adjustments are performed using a bisection method. First, a search interval for the control quantity adjustment is determined. The lower limit of the search interval is the maximum allowable control quantity adjustment for the controlled object (negative), and the upper limit is the maximum allowable control quantity adjustment for the controlled object (positive). The midpoint of the search interval is taken as the current candidate adjustment quantity, and the predicted temperature change rate under this adjustment quantity is calculated. If the predicted temperature change rate is greater than the upper limit of the acceptable temperature change rate range (0.5℃ / s), the lower limit of the search interval is adjusted to the current midpoint value; if the predicted temperature change rate is less than the lower limit of the acceptable temperature change rate range (-0.5℃ / s), the upper limit of the search interval is adjusted to the current midpoint value; if the predicted temperature change rate falls within the acceptable range, iteration stops, and the current candidate adjustment quantity is used as the required control quantity adjustment quantity. The number of iterations does not exceed 10. If convergence is not achieved after 10 iterations, the candidate adjustment quantity from the last iteration is taken as the required control quantity adjustment quantity. At this point, the proposed control quantity adjustment quantity is the required control quantity adjustment quantity.

[0101] After determining the control adjustment amount, calculate the control adjustment coefficient. The formula for calculating the control adjustment coefficient is:

[0102]

[0103] in, This is the current control value. Control adjustment coefficient. The sign indicates the direction of control adjustment; a positive value indicates an increase in the control quantity, and a negative value indicates a decrease in the control quantity.

[0104] It should be noted that by dividing the predicted trajectory into a hysteresis hold segment and a response activation segment, and by not immediately changing the predicted temperature change rate within the hysteresis hold segment, the physical characteristics of the thermal response delay of the controlled object are fully considered. This avoids the problem of mistakenly believing that the control quantity is insufficient and thus over-adjusting because the temperature has not yet begun to respond after the control quantity is adjusted. By performing prediction correction within the response activation segment, the determination of the control quantity adjustment is precisely matched with the actual response characteristics, effectively avoiding light output fluctuations caused by premature prediction and excessive control quantity adjustment, thereby improving the smoothness and stability of the control.

[0105] Furthermore, after determining the control adjustment coefficient, the target control value is calculated based on the control adjustment coefficient and the current control value of the controlled object. The formula for calculating the target control value is:

[0106]

[0107] in, For the target control value, This is the current control value.

[0108] For example, assuming the current temperature change rate is 3.5℃ / s, showing an upward trend, and the temperature response coefficient m under the current operating condition is equal to -0.4, meaning that for every unit increase in control input, the temperature change rate decreases by 0.4℃ / s. To reduce the temperature change rate from 3.5℃ / s to 0℃ / s, the required change in control input is... Where 0.8 is a safety factor used to avoid over-adjustment, calculated as follows: This is equivalent to an increase of 7 units in control input. If the current control input is 350mA, then the target control input is 357mA. Control input adjustment factor. 7 divided by 350 equals 0.02. The safety factor is generally adjusted between 0.7 and 0.95 based on the model identification accuracy and measurement noise level. Higher model accuracy and lower measurement noise result in more accurate calculation of the control adjustment, allowing for a larger safety factor (closer to 0.95) to accelerate the adjustment response. Conversely, when model accuracy is low or measurement noise is high, a smaller safety factor (closer to 0.7) is used to avoid over-adjustment due to model errors. In this embodiment, the safety factor is 0.8.

[0109] Figure 3 This is a schematic diagram of the gradual adjustment of the control quantity in a light output control method based on temperature change prediction according to the present invention. Figure 3 The diagram shows the curve of the control variable gradually adjusting from its current value to the target control variable value. The horizontal axis represents time, and the vertical axis represents the control variable value. The curve smoothly changes from the initial control variable value to the target control variable value. Throughout the adjustment process, the rate of change of the control variable remains constant and does not exceed the preset maximum rate of change. The adjustment process employs a gradual approach, meaning the control variable changes from its current value to the target value continuously and smoothly, rather than through abrupt changes, to avoid any shocks to the controlled object or perceptible fluctuations in the output.

[0110] Specifically, the maximum rate of change is generally 1% to 10% of the rated control quantity per second. The larger the thermal time constant, the slower the controlled object responds to changes in the control quantity; therefore, the maximum rate of change should be smaller to avoid overshooting due to the control quantity adjustment speed exceeding the physical response capability of the controlled object. The higher the system response speed requirement, the more desirable it is for the controlled object's control quantity to reach the target value in a shorter time; therefore, the maximum rate of change should be larger. For example, this embodiment sets the maximum rate of change to 5% of the rated control quantity per second. Control quantity adjustment is achieved through pulse width modulation (PWM). The target control quantity value is converted into the corresponding PWM duty cycle. The PWM frequency is generally set within the range of 200Hz to 2000Hz. Too low a frequency may cause flicker perceptible to the human eye, while too high a frequency increases switching losses. For example, 1000Hz is used. By changing the duty cycle of the PWM signal, the output control quantity of the drive circuit is controlled, allowing the controlled object's control quantity to smoothly change from its current value to the target control quantity value.

[0111] Furthermore, after completing the control quantity adjustment, the current control quantity value and current temperature value of the controlled object are obtained. The control quantity value is obtained from the voltage across the sampling resistor of the drive circuit after amplification and analog-to-digital conversion, and the temperature value is provided by the temperature acquisition results.

[0112] In this embodiment, the current light output value of the controlled object is estimated based on the current control quantity and current temperature value through a preset mapping relationship between control quantity, temperature, and light output. The estimation method is as follows: using the current control quantity and current temperature value as query conditions, a matching light output value is searched in the mapping relationship table. If the current control quantity and current temperature value are completely consistent with a set of data in the calibration table, the corresponding light output value is directly read. If the current control quantity and current temperature value are between adjacent data points in the calibration table, the corresponding light output value is calculated using bilinear interpolation. Linear interpolation is first performed on the control quantity dimension, and then on the temperature dimension to obtain the estimated light output value under the current state. Bilinear interpolation can fully utilize the information from four adjacent data points in the calibration table, obtaining a more accurate estimation result than a simple search. The estimated current light output value is used for subsequent deviation comparison with the target light output value and verification of the adjustment effect.

[0113] Specifically, during the calibration phase before the controlled object leaves the factory, the control quantity and ambient temperature of the controlled object are adjusted with a preset step size, and the light output value under each combination is measured. During the calibration phase, the controlled object is placed in a constant temperature chamber, and the ambient temperature is varied from -20°C to 60°C in 10°C steps. At each temperature point, the control quantity is varied from 10% to 100% of the rated control quantity in 5% steps. The luminous flux or illuminance value under each combination is measured using an integrating sphere or a spectroradiometer. Each measurement point is measured three times repeatedly, and the average value is taken as the light output value under that combination to reduce the impact of random measurement errors on the calibration results.

[0114] The measured control values, temperature values, and light output values ​​are fitted to establish a correspondence between them, serving as a mapping relationship. The specific fitting method is as follows: a bivariate polynomial fitting method is used, with the control values ​​and temperature values ​​as independent variables and the light output value as the dependent variable. The fitting function form is:

[0115]

[0116] Where L is the light output value, in lm; I is the control value, in A; and T is the temperature value, in °C. to The fitting coefficients are used. The optimal values ​​of the fitting coefficients are determined using the least squares method. The measurement data are compiled into a three-dimensional data table, and the correspondence between the control values, temperature values, and light output values, along with the fitting coefficients, constitute a mapping relationship.

[0117] Obtain the preset target light output value, which is the desired light output level of the controlled object. The target light output value is typically the luminous flux value of the controlled object under rated operating conditions or the light output value corresponding to the brightness level set by the user. Compare the current light output value with the target light output value, and verify the adjustment effect of the control quantity based on the comparison result.

[0118] Specifically, the deviation between the current light output value and the target light output value is calculated. The formula for calculating the deviation value is:

[0119]

[0120] in, The deviation value is expressed as a percentage. This represents the current light output value. This represents the target light output value.

[0121] Specifically, when the deviation value exceeds a preset deviation threshold, the adjustment effect is determined to be substandard, and a closed-loop correction signal is generated. The preset deviation threshold is generally set within the range of 2% to 10% according to the system accuracy requirements; for example, the preset deviation threshold is set to 5%.

[0122] Furthermore, after generating the closed-loop correction signal, the closed-loop correction amount is determined based on the deviation value, and the control quantity is adjusted again based on the closed-loop correction amount. The method for determining the closed-loop correction amount is as follows: if the current optical output value is lower than the target optical output value, the closed-loop correction amount is positive, i.e., the control quantity is increased; if the current optical output value is higher than the target optical output value, the closed-loop correction amount is negative, i.e., the control quantity is decreased. The magnitude of the closed-loop correction amount is determined proportionally based on the deviation value. To avoid over-correction causing the optical output value to oscillate back and forth around the target value, each closed-loop correction amount does not exceed 50% of the previous control quantity adjustment. Taking an initial deviation of 10% as an example, using this correction step size, the deviation can be reduced to below 1.25% after 3 corrections, meeting the system accuracy requirements. The closed-loop correction ratio can be adjusted within the range of 0.3 to 0.8 according to the system convergence speed requirements and the optical output measurement noise level. A larger value is used when the convergence speed requirement is high, and a smaller value is used when the measurement noise is high to avoid incorrect correction.

[0123] After the closed-loop correction is completed, the optical output estimation and deviation verification are performed again. If the deviation value still exceeds the preset deviation threshold, the closed-loop correction continues until the deviation value drops below the preset deviation threshold or the number of corrections reaches the preset maximum number of times. The preset maximum number of times is generally set in the range of 2 to 4 times; for example, the preset maximum number of times is set to 3 times. The basis for setting the preset maximum number of times to 3 times is: under the half-step correction strategy with a 50% correction step size, the remaining deviation after n iterations is the initial deviation multiplied by 0.5 to the power of n. Calculated with an initial deviation of 10%, the remaining deviation after 3 iterations is... The deviation is already below the 5% threshold, meeting the system accuracy requirements. Increasing the number of iterations offers limited improvement in accuracy; after the fourth iteration, the remaining deviation is 0.625%, but this increases system response time and processor overhead. Therefore, setting the preset maximum number of iterations to three strikes a balance between control accuracy and system response speed. In practical applications, the preset maximum number of iterations can be adjusted between two and four, depending on the system's control accuracy requirements. If the deviation still exceeds the preset deviation threshold after reaching the maximum number of iterations, the system outputs an adjustment anomaly alarm signal, notifying the user to conduct a manual check.

[0124] like Figure 4 As shown, a light output control system based on temperature change prediction is used to implement a light output control method based on temperature change prediction, comprising:

[0125] The temperature acquisition module obtains the current temperature value of the controlled object;

[0126] The rate of change calculation module calculates the rate of temperature change based on the current temperature value across multiple consecutive sampling periods.

[0127] The direction determination module compares the temperature change rate with a preset direction determination threshold and determines the direction of temperature change based on the comparison result. The direction of change includes a first direction, a second direction, and a third direction. The first direction is opposite to the second direction, and the third direction is a direction between the first direction and the second direction. When the direction of change is the first direction and the temperature change rate exceeds the preset prediction adjustment trigger threshold, or when the direction of change is the second direction and the absolute value of the temperature change rate exceeds the preset prediction adjustment trigger threshold, a prediction adjustment start signal is generated.

[0128] The control quantity adjustment module, after generating the predictive adjustment start signal, determines the control quantity adjustment coefficient based on the temperature change rate, calculates the target control quantity value based on the control quantity adjustment coefficient and the current control quantity of the controlled object, and adjusts the control quantity of the controlled object according to the target control quantity value to control the light output value of the controlled object.

[0129] The light output verification module, after adjusting the control quantity, obtains the current control quantity value and the current temperature value of the controlled object. Through the preset mapping relationship between the control quantity, temperature and light output, it determines the current light output value of the controlled object based on the current control quantity value and the current temperature value. The current light output value is compared with the preset target light output value, and the adjustment effect of the control quantity is verified based on the comparison result.

[0130] In this embodiment, the temperature acquisition module continuously acquires the temperature value of the controlled object at a preset sampling period. The sampling period is set according to the system's real-time requirements and the temperature change rate. The current temperature value of the controlled object is obtained through the temperature sensor. The temperature value is expressed in °C. At the same time as acquiring the temperature value, the acquisition time of each temperature value is recorded to form a corresponding data sequence of time and temperature. This provides a time reference for the subsequent calculation of the temperature change rate, thereby ensuring the time continuity and traceability of the temperature data and providing an accurate data basis for the calculation of the temperature change rate.

[0131] The rate of change calculation module acquires temperature values ​​over N consecutive sampling periods, where N is a positive integer greater than or equal to 3. Based on these N consecutive sampling periods, it determines the linear trend of the temperature change and obtains the slope of the temperature change over time. This slope is then used as the rate of temperature change. The least squares method is employed for linear fitting, making full use of temperature data from multiple sampling points. This effectively suppresses the influence of single-point noise on the rate of change calculation, making the calculation results of the temperature rate of change more reliable and accurate. This provides an accurate decision-making basis for subsequent direction determination and predictive adjustment triggering.

[0132] The direction determination module compares the temperature change rate with preset first and second direction determination thresholds. When the temperature change rate is greater than the first direction determination threshold, the change direction is determined to be the first direction, i.e., the temperature is rising. When the temperature change rate is less than the second direction determination threshold, the change direction is determined to be the second direction, i.e., the temperature is falling. When the temperature change rate is between the first and second direction determination thresholds, the change direction is determined to be the third direction, i.e., the temperature is stable. When the temperature change rate is determined to be the first direction and exceeds the predictive adjustment trigger threshold, or when the temperature change rate is determined to be the second direction and exceeds the predictive adjustment trigger threshold, a predictive adjustment start signal is generated. This makes the control trigger condition bidirectionally correlated with the temperature change trend and rate, avoiding frequent false triggers in the stable temperature state and improving the accuracy and effectiveness of control start.

[0133] After generating the predictive regulation start signal, the control quantity adjustment module acquires historical temperature change data and historical control quantity adjustment data of the controlled object. It extracts the control quantity values ​​before and after each control quantity adjustment from the historical control quantity adjustment data, and extracts the temperature change rate sequence before and after each control quantity adjustment from the historical temperature change data. For each control quantity adjustment, it determines the lag time at which the temperature change rate begins to generate a stable response after the adjustment. The lag time, the temperature change rate before adjustment, the change in temperature change rate after adjustment, and the control quantity adjustment amount together constitute a response sample. Based on the current temperature value, the current control quantity value, and the current direction of change, it selects matching samples from the response sample to generate the temperature response relationship under the current operating condition. Based on the temperature change rate and the temperature response relationship, it determines the control quantity adjustment coefficient. Based on the control quantity adjustment coefficient and the current control quantity, it calculates the target control quantity value and adjusts the control quantity of the controlled object according to the target control quantity value. By introducing lag time extraction and operating condition matching screening, the establishment of temperature response relationship can more accurately reflect the actual thermal response characteristics of the controlled object; by dividing the predicted trajectory into a lag hold segment and a response effective segment for segmented prediction, fluctuations in light output caused by premature prediction and excessive adjustment of control quantity are avoided.

[0134] After completing the control quantity adjustment, the light output verification module acquires the current control quantity value and the current temperature value of the controlled object. Based on the current control quantity value and the current temperature value, it determines the current light output value of the controlled object through the preset mapping relationship between control quantity, temperature and light output. The current light output value is compared with the preset target light output value. The adjustment effect of the control quantity is verified based on the comparison result. The light output closed-loop verification confirms whether the light output has reached the expected target. This forms a closed-loop control link of adjustment, verification and correction, ensuring the stability and accuracy of the light output of the controlled object during temperature changes.

[0135] The invention will be further explained below with reference to a specific application scenario.

[0136] Assuming an LED light fixture is operating normally with a control input (drive current) of 350mA and a current temperature of 45℃, the temperature acquisition module continuously collects temperature values ​​at a sampling period of 100ms. Over 10 consecutive sampling periods, the temperature gradually increases from 45.1℃ to 47.3℃. The rate of change calculation module performs a linear fit on these 10 temperature values, obtaining a slope k equal to 2.2℃ / s.

[0137] The direction determination module compares k with the first direction determination threshold of 0.5℃ / s. If k is greater than 0.5℃ / s, the direction of change is determined to be the first direction, i.e., temperature rise. Then, k is compared with the predictive adjustment trigger threshold of 2.0℃ / s. If k is greater than 2.0℃ / s, the trigger condition is met, and the direction determination module generates a predictive adjustment start signal.

[0138] After receiving the predictive regulation start signal, the control quantity adjustment module acquires historical temperature change data and historical control quantity adjustment data. By analyzing the historical data, it extracts the lag time, the temperature change rate before adjustment, the change in the temperature change rate after adjustment, and the control quantity adjustment from each control quantity adjustment to form a response sample. It selects the response sample that matches the current temperature range, the current control quantity range, and the current direction of change to generate the temperature response relationship under the current operating condition, and obtains a temperature response coefficient m equal to -0.4.

[0139] The current temperature change rate is 2.2℃ / s. Based on the hysteresis hold period, the prediction time axis is divided into a hysteresis hold period and a response activation period. Within the response activation period, to reduce the temperature change rate to 0℃ / s, the proposed control variable adjustment is iteratively adjusted so that the predicted temperature change rate falls within the acceptable temperature change rate range (-0.5℃ / s to 0.5℃ / s). The control variable adjustment determined after iterative convergence is 5.5mA. The current control variable is 350mA, and the target control variable value is 350, which equals 355.5mA.

[0140] The control quantity adjustment module adjusted the control quantity from 350mA to 355.5mA. During the adjustment process, the rate of change of the control quantity did not exceed 5% of the rated control quantity per second. The rated control quantity was 500mA, i.e., not exceeding 25mA / s. The actual change in the control quantity was 5.5mA, and the adjustment time was 0.22 seconds. After the adjustment was completed, the rate of temperature rise was suppressed, and the temperature of the controlled object gradually stabilized.

[0141] Subsequently, the light output verification module acquires the adjusted control value and temperature value, and estimates the current light output value through a preset mapping relationship. Based on the current light output value and the target light output value, the deviation value is obtained through the deviation value calculation formula. If the deviation value does not exceed the deviation threshold of 5%, the adjustment effect is deemed satisfactory, and no closed-loop correction is required.

[0142] Through the above process, the light output control method and system based on temperature change prediction of the present invention realizes adaptive control quantity adjustment based on temperature change rate prediction during the temperature change of the controlled object. This changes the control trigger from the traditional temperature threshold trigger to the temperature change rate trend trigger. The control strategy uses historical coupling data for prediction and avoids premature or excessive control quantity adjustment through segmented prediction. A closed loop is formed through light output verification, ensuring the stability and accuracy of light output of the controlled object during temperature change.

[0143] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A light output control method based on temperature change prediction, characterized in that, include: Get the current temperature value of the controlled object; The rate of temperature change is calculated based on the current temperature value from multiple consecutive sampling periods; The temperature change rate is compared with a preset direction determination threshold, and the direction of temperature change is determined based on the comparison result. When the direction of change is a first direction and the rate of temperature change exceeds a preset prediction adjustment trigger threshold, or when the direction of change is a second direction and the absolute value of the rate of temperature change exceeds the prediction adjustment trigger threshold, a prediction adjustment start signal is generated. After generating the predictive regulation start signal, the control quantity adjustment coefficient is determined according to the temperature change rate, and the target control quantity value is calculated based on the control quantity adjustment coefficient and the current control quantity of the controlled object. Adjust the control quantity of the controlled object according to the target control quantity value to control the light output value of the controlled object.

2. The light output control method based on temperature change prediction according to claim 1, characterized in that, The calculation of the temperature change rate based on the current temperature value from multiple consecutive sampling periods includes: Obtain the temperature values ​​for N consecutive sampling periods, where N is a positive integer greater than or equal to 3; The linear trend of the temperature value is determined based on the temperature value of the N consecutive sampling periods, and the slope of the temperature value changing with time is obtained. The slope is used as the rate of temperature change.

3. The light output control method based on temperature change prediction according to claim 1, characterized in that, The direction determination threshold includes a first direction determination threshold and a second direction determination threshold. The first direction determination threshold is a positive value, and the second direction determination threshold is a negative value. The change direction includes a first direction, a second direction, and a third direction. The first direction is opposite to the second direction, and the third direction corresponds to the direction where the temperature change rate is between the second direction determination threshold and the first direction determination threshold. The step of comparing the temperature change rate with a preset direction determination threshold and determining the direction of temperature change based on the comparison result includes: When the rate of temperature change is greater than the first direction determination threshold, the direction of change is determined to be the first direction; When the rate of temperature change is less than the second direction determination threshold, the direction of change is determined to be the second direction; When the rate of temperature change is greater than or equal to the second direction determination threshold and less than or equal to the first direction determination threshold, the direction of change is determined to be the third direction.

4. The light output control method based on temperature change prediction according to claim 1, characterized in that, The step of determining the control quantity adjustment coefficient based on the temperature change rate includes: Acquire historical temperature change data and historical control quantity adjustment data of the controlled object; Extract the control quantity values ​​before and after each control quantity adjustment from the historical control quantity adjustment data, and extract the temperature change rate sequence before and after each control quantity adjustment from the historical temperature change data; For each control quantity adjustment, based on the temperature change rate sequence, determine the lag time corresponding to the start of a stable response in the temperature change rate after the control quantity adjustment, and combine the lag time, the temperature change rate before adjustment, the change in temperature change rate after adjustment, and the control quantity adjustment amount to form a response sample. The current temperature range is determined based on the current temperature value, the current control range is determined based on the current control quantity, and the current direction of change is determined based on the temperature change rate. Select response samples from the response samples that match the current temperature range, the current control range, and the current direction of change, and generate the temperature response relationship under the current operating condition based on the selected response samples; The control quantity adjustment coefficient is determined based on the temperature change rate and the temperature response relationship under the current operating conditions.

5. The light output control method based on temperature change prediction according to claim 4, characterized in that, Determining the control quantity adjustment coefficient based on the temperature change rate and the temperature response relationship under the current operating condition includes: The average value of the hysteresis time in the response samples is taken as the hysteresis hold period, which is used to characterize the delay duration from the start of control quantity adjustment to the start of temperature change rate response; Starting from the control quantity adjustment time, the prediction time axis is divided into a lag hold period and a response activation period according to the lag hold period. During the hysteresis hold period, the predicted temperature change rate continues according to the current temperature change rate. Within the effective response period, the predicted temperature change rate is corrected based on the temperature response relationship under the current operating condition. The control quantity adjustment coefficient is determined based on the comparison between the corrected predicted temperature change rate within the effective response segment and the preset target temperature change rate.

6. The light output control method based on temperature change prediction according to claim 1, characterized in that, Also includes: After adjusting the control quantity, the current control quantity value and current temperature value of the controlled object are obtained; Based on the current control value and the current temperature value, the current light output value of the controlled object is determined through a preset mapping relationship between the control value, temperature and light output. Obtain the preset target light output value; The current light output value is compared with the target light output value, and the adjustment effect of the control quantity is verified based on the comparison result.

7. The light output control method based on temperature change prediction according to claim 6, characterized in that, The mapping relationship is established as follows: During the calibration phase before the controlled object leaves the factory, the control quantity value and ambient temperature value of the controlled object are adjusted with a preset step size, and the light output value under each combination is measured. The measured control value, temperature value, and light output value are fitted to establish a correspondence between them, which serves as the mapping relationship.

8. The light output control method based on temperature change prediction according to claim 6, characterized in that, The step of verifying the adjustment effect of the control quantity based on the comparison results includes: Calculate the deviation between the current light output value and the target light output value; When the deviation value exceeds the preset deviation threshold, it is determined that the adjustment effect has not met the standard, and a closed-loop correction signal is generated. After generating the closed-loop correction signal, the closed-loop correction amount is determined based on the deviation value, and the control quantity is adjusted again based on the closed-loop correction amount. After readjusting the control quantity, the current light output value of the controlled object is re-determined and compared with the target light output value. If the deviation value still exceeds the preset deviation threshold, the steps of generating a closed-loop correction signal and readjusting the control quantity are repeated until the deviation value does not exceed the preset deviation threshold or the number of repetitions reaches the preset maximum number of repetitions.

9. The light output control method based on temperature change prediction according to claim 1, characterized in that, The step of adjusting the control quantity of the controlled object according to the target control quantity value includes: The control quantity of the controlled object is adjusted from its current value to the target control quantity value, and the rate of change of the control quantity during the adjustment process does not exceed the preset maximum rate of change.

10. A light output control system based on temperature change prediction, characterized in that, A light output control method based on temperature change prediction for implementing any one of claims 1 to 9 includes: The temperature acquisition module obtains the current temperature value of the controlled object; The rate of change calculation module calculates the temperature change rate based on the current temperature value over multiple consecutive sampling periods; The direction determination module compares the temperature change rate with a preset direction determination threshold and determines the direction of temperature change based on the comparison result. When the direction of change is a first direction and the temperature change rate exceeds a preset prediction adjustment trigger threshold, or when the direction of change is a second direction and the absolute value of the temperature change rate exceeds the preset prediction adjustment trigger threshold, a prediction adjustment start signal is generated. When the direction of change is a third direction, no prediction adjustment start signal is generated. The control quantity adjustment module, after generating the predictive adjustment start signal, determines the control quantity adjustment coefficient based on the temperature change rate, calculates the target control quantity value based on the control quantity adjustment coefficient and the current control quantity of the controlled object, and adjusts the control quantity of the controlled object according to the target control quantity value to control the light output value of the controlled object; The light output verification module, after executing the adjustment of the control quantity, obtains the current control quantity value and the current temperature value of the controlled object. Based on the current control quantity value and the current temperature value, and through a preset mapping relationship between the control quantity, temperature and light output, it determines the current light output value of the controlled object. The current light output value is compared with a preset target light output value, and the adjustment effect of the control quantity is verified based on the comparison result.

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