A wide-range light power self-adaptive tuning method suitable for a triangulation system

Abstract

The application discloses a wide-range light power self-adaptive tuning method suitable for a triangulation system, and comprises the following steps: S1, acquiring signal characteristic parameters of the triangulation system, wherein the signal characteristic parameters comprise saturation power and noise power; S2, setting an adaptive interval according to the saturation power and the noise power by the triangulation system; S3, collecting a current signal peak value and judging whether the current signal peak value is greater than the noise power; S4, if the current signal peak value is greater than the noise power, the current signal peak value is an effective signal, a first tuning step is carried out, the current signal peak value is compared with the adaptive interval, and the following operations are performed according to the comparison result: compared with the prior art, the LD power and the CMOS integration time are tuned in cooperation and in steps, wide-range and fine tuning of the light power is realized, the LD is ensured to be maintained at a low power level in most working states, and therefore the aging process of the laser is significantly slowed down, and the effective working life is prolonged.

Description

Technical Field

[0001] This invention relates to the field of photoelectric measurement, and more specifically to a wide-range adaptive optical power tuning method adapted to triangulation systems. Background Technology

[0002] Laser displacement sensors based on the triangulation principle are widely used in industrial automation, precision manufacturing, and robotics due to their advantages such as non-contact operation, high precision, high speed, and compact structure. However, in practical industrial applications, the surface characteristics (such as color, roughness, and material) of the objects being measured vary greatly. For example, dark or rough surfaces absorb or scatter more laser energy, resulting in a weak returned signal; while bright or smooth surfaces reflect excessively strong signals. This leads to a very large dynamic range of optical power received by image sensors (such as CMOS), often exceeding the sensor's optimal response range, thus severely affecting measurement accuracy and stability.

[0003] To address the aforementioned issues, several adaptive optical power control schemes have been proposed in the prior art. Scheme one involves changing the emitted light intensity by tuning the drive power of the laser diode (LD); scheme two involves tuning the exposure or integration time of the CMOS sensor; and scheme three involves tuning the amplification gain of the back-end signal processing circuit. However, existing schemes still have the following drawbacks: 1. Simply tuning the LD power, integration time, or circuit gain often results in an insufficient dynamic range to cover extreme application scenarios ranging from highly reflective mirrors to pure black light-absorbing surfaces; 2. Long-term or frequent large increases in LD power accelerate laser aging, significantly shorten its lifespan, and increase maintenance costs and system instability; 3. The selection of the tuning step is crucial during adaptive tuning. Too small a fixed step size will result in too many tuning iterations and an excessively long response time, failing to meet the requirements of rapid measurement; too large a fixed step size will easily cause the optical power to oscillate around the target value, making the system unstable and even causing fluctuations in the measurement results; 4. Tuning is only performed on a single parameter, failing to develop a priority tuning strategy that coordinates multiple means such as LD power and integration time based on the actual signal conditions (such as excessively strong or weak signals) to achieve globally optimal control. Summary of the Invention

[0004] The purpose of this invention is to address the problems of narrow adaptive range, damaged LD lifetime, and low tuning efficiency in the existing technology. To address these shortcomings, a wide-range optical power adaptive tuning method suitable for triangulation systems is proposed.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A wide-range adaptive optical power tuning method adapted to triangulation systems includes the following steps:

[0007] S1. Obtain the signal characteristic parameters of the triangulation system, wherein the signal characteristic parameters include saturation power and noise power;

[0008] S2. The triangulation system sets an adaptive range based on saturation power and noise power.

[0009] S3. Collect the current signal peak value and determine whether the current signal peak value is greater than the noise power;

[0010] S4. If the current signal peak value is greater than the noise power, it is a valid signal. Perform the first tuning step, compare the current signal peak value with the adaptive range, and perform the following operations based on the comparison result:

[0011] If the current signal peak value is higher than the upper limit of the adaptive range, the laser's emission power and the image sensor's integration time are tuned according to the first priority order to make the signal peak value fall within the adaptive range. The first priority order is: first reduce the laser's emission power, and then reduce the integration time when the emission power reaches the adjustable lower limit.

[0012] If the current signal peak is lower than the lower limit of the adaptive range, the laser's emission power and the image sensor's integration time are tuned according to the second priority order to make the signal peak fall within the adaptive range. The second priority order is: first increase the integration time, and then increase the emission power when the integration time reaches the current adjustable upper limit.

[0013] Furthermore, in the first tuning step, the tuning amount of any parameter is determined according to a preset variable step strategy. The variable step strategy includes: calculating the deviation state judgment coefficient and deviation ratio of the current signal peak relative to the corresponding limit of the target power range; calculating the variable step according to the deviation ratio and the number of tuning steps; and performing tuning according to the variable step.

[0014] As a further preferred embodiment of the present invention, obtaining the saturation power specifically includes: increasing the emission power of the laser in fixed steps until the signal peak reaches a preset saturation threshold, and recording the emission power at this time as the saturation power;

[0015] Obtaining noise power specifically involves: setting the laser's emission power to the minimum, acquiring and recording the signal peak value multiple times with the same integration time, and taking the maximum value of the signal peak value as the noise power.

[0016] As a further preferred embodiment of the present invention, S2 specifically includes:

[0017] Calculate reference point Reference point This is the midpoint between saturation power and noise power;

[0018] Based on reference point and the preset adaptive interval half width Set the adaptive interval as .

[0019] As a further preferred embodiment of the present invention, in step S3, if the current signal peak value is not greater than the noise power, then step S3 is repeated and continues to be executed within a preset time. If the signal peak value is not greater than the noise power within the preset time, then it is determined that there is no valid signal, and the current parameters are maintained or an alarm signal is issued.

[0020] As a further preferred embodiment of the present invention, in step S4, the current adjustable upper limit of the integration time is constrained by the current sampling frequency of the triangulation system; if the current sampling frequency is higher than the preset frequency threshold, then no integration time tuning is performed.

[0021] As a further preferred embodiment of the present invention, the preset frequency threshold is 50kHz.

[0022] As a further preferred embodiment of the present invention, in step S4, after each tuning, a preset response stabilization time is waited before the signal peak value is re-acquired and the next round of judgment and tuning is performed.

[0023] As a further preferred embodiment of the present invention, the deviation state judgment coefficient m,

[0024] .

[0025] As a further preferred embodiment of the present invention, in the variable stepping strategy...

[0026] Preset maximum number of tuning times N;

[0027] Before tuning, calculate the deviation state judgment coefficient m. .

[0028] The deviation state judgment coefficient m is calculated based on the current signal peak value.

[0029] When 0≤m≤1, no tuning is needed, and monitoring continues;

[0030] When m < 0 or m > 1, tuning is required.

[0031] During tuning, if m < 0, it is judged as a negative deviation. The current signal peak is lower than the left endpoint, and the deviation ratio K = [(Pref - Poff) - Pmax] / (Pref - Poff). Then, the tuning is performed according to the time priority strategy of ramp-up integration.

[0032] Calculate the variable step size r, r = K / (Ni);

[0033] Priority tuning integral time ,

[0034] Points Time Tuning to the adjustable lower limit of integral time If this happens, the LD power is tuned, and the tuning count is reset.

[0035] Current signal peak value P max Multiply by (1+r) to get the peak value of the tuned signal, and use the peak value of the tuned signal as the current peak value of the signal, P max = P max ×(1+r)

[0036] Within the upper limit N of the tuning number (i≤N), if the current signal peak value P max If the signal peak value is within the target power range, the tuning is successful, the tuning ends, and the tuning count is reset; if the current signal peak value P max If the target power range is still within, continue tuning until the number of tuning times exceeds the upper limit N (i>N), then stop tuning, reset the number of tuning times, and output an alarm signal;

[0037] If m > 1, it is judged as a positive deviation, the current signal peak is higher than the right endpoint, and the deviation ratio K = [Pmax - (Pref + Poff)] / (Pref + Poff); then the tuning is performed according to the power reduction priority strategy.

[0038] Calculate the variable step size r, r = K / (Ni);

[0039] Priority tuning signal peak P max P max = P max ×(1-r)

[0040] Within the upper limit N of the tuning number (i≤N), if the current signal peak value P max If the signal peak value is within the target power range, the tuning is successful, the tuning ends, and the tuning count is reset; if the current signal peak value P max If the target power range is still within, continue tuning until the number of tuning times exceeds the upper limit N (i>N), then stop tuning, reset the number of tuning times, and output an alarm signal;

[0041] Current signal peak value P max Tune to the adjustable lower limit of transmit power When, then tune the integral time. At the same time, the tuning count is reset;

[0042] Current tuning integral time Multiply by (1-r) to get the tuned integration time, and use the tuned integration time as the current integration time. ;

[0043] Before each tuning, the deviation state judgment coefficient m and deviation ratio K need to be recalculated.

[0044] As a further preferred embodiment of the present invention, in S4, when the number of tuning times exceeds the upper limit N of the number of tuning times, the current signal peak value is higher than the upper limit of the adaptive range and the laser's emission power has dropped to its adjustable lower limit and the integration time has dropped to its adjustable lower limit, or when the current signal peak value is lower than the lower limit of the adaptive range and the integration time has increased to its current adjustable upper limit and the emission power has increased to its adjustable upper limit, it is determined that the system's adaptive capability range is exceeded, and the current parameters are maintained or an alarm signal is output.

[0045] The present invention proposes a wide-range adaptive optical power tuning method for triangulation systems, which has the following advantages compared with the prior art:

[0046] 1. This invention achieves wide-range and fine-tuning of optical power by coordinating and step-by-step tuning of LD power and CMOS integration time, which can effectively accommodate various extreme measurement scenarios from high-brightness reflective surfaces to low-reflectivity dark surfaces, greatly improving the versatility and environmental adaptability of the sensor.

[0047] 2. This invention adopts a priority tuning strategy. When the signal is too strong, the LD power is reduced first to protect the laser. When the signal is too weak and needs to be boosted, the integration time of the CMOS is extended first, rather than directly increasing the LD power. This strategy of prioritizing power reduction and postponing power increase ensures that the LD maintains a low power level in most operating conditions, thereby significantly slowing down the aging process of the laser, extending its effective working life, and reducing the long-term operating cost of the system.

[0048] 3. This invention employs a segmented fixed-step strategy based on deviation percentage, which determines the optimal tuning step in a single calculation, eliminating the need for multiple iterations and trial and error, resulting in a faster response speed. Furthermore, the fine division of the segmented intervals (0~5%, 5~15%, 15~30%, 30~50%, >50%) ensures that the system can match the most suitable step at any degree of deviation, achieving an optimal balance between efficiency and accuracy. Attached Figure Description

[0049] Figure 1 This is the adaptive range calibration logic diagram of the present invention. Detailed Implementation

[0050] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0051] This patent proposes a wide-range adaptive optical power tuning method suitable for triangulation systems. By coordinating the tuning of laser power and sensor integration time, and employing a variable step proportional control strategy, it achieves wide dynamic range, high efficiency, and laser-friendly adaptive optical power control. It can comprehensively tune according to the priority order in various scenarios, which can efficiently increase the adaptive range while maximizing the lifespan of the optical emission module (LD). This allows a displacement sensor to be adapted to more application scenarios, making it more conducive to the promotion of product application scenarios.

[0052] Example 1: Combining Figure 1 A wide-range adaptive optical power tuning method adapted to triangulation systems, specifically including:

[0053] A wide-range adaptive optical power tuning method adapted to triangulation systems includes the following steps:

[0054] S1. Obtain the signal characteristic parameters of the triangulation system, including saturation power. and noise power .

[0055] Obtaining saturation power specifically includes: using fixed steps Increase the emission power of the laser For example, the power is increased in fixed steps of 1% until the signal peak reaches a preset saturation threshold, at which point the transmit power is reduced. denoted as saturated power .

[0056] Obtain noise power Specifically, this includes: increasing the laser's emission power Set to minimum, and acquire and record the signal peak value M times with the same integration time. The maximum value of the signal peak is taken as the noise power. .

[0057] .

[0058] S2. The triangulation system sets an adaptive range based on saturation power and noise power.

[0059] First calculate the reference point , ;

[0060] Based on reference point and the preset adaptive interval half width Set the adaptive interval as .

[0061] S3, Collect the current signal peak value and judge If the current signal peak value Not greater than noise power If S3 is executed repeatedly, it will continue to execute for a preset time, which is 3ms-5ms; if it continues to execute for the preset time... If no valid signal is detected, the current parameters will be maintained or an alarm signal will be issued.

[0062] S4. If the current signal peak value is greater than the noise power, it is a valid signal; proceed to the first tuning step.

[0063] S4. If the current signal peak value is greater than the noise power, it is a valid signal. Perform the first tuning step, compare the current signal peak value with the adaptive range, and perform the following operations based on the comparison result:

[0064] If the current signal peak value is higher than the upper limit of the adaptive range, the laser's emission power and the image sensor's integration time are tuned according to the first priority order to make the signal peak value fall within the adaptive range. The first priority order is: first reduce the laser's emission power, and then reduce the integration time when the emission power reaches the adjustable lower limit.

[0065] If the current signal peak is lower than the lower limit of the adaptive range, the laser's emission power and the image sensor's integration time are tuned according to the second priority order to make the signal peak fall within the adaptive range. The second priority order is: first increase the integration time, and then increase the emission power when the integration time reaches the current adjustable upper limit.

[0066] In the first tuning step, the tuning amount of any parameter is determined according to a preset variable step strategy. The variable step strategy includes: calculating the deviation state judgment coefficient and deviation ratio of the current signal peak relative to the corresponding limit of the target power range; calculating the variable step according to the deviation ratio and the number of tunings; and performing tuning according to the variable step.

[0067] In variable step strategy:

[0068] Preset maximum number of tuning times N;

[0069] Before tuning, calculate the deviation state judgment coefficient m. .

[0070] The deviation state judgment coefficient m is calculated based on the current signal peak value.

[0071] When 0≤m≤1, no tuning is needed, and monitoring continues;

[0072] When m < 0 or m > 1, tuning is required.

[0073] During tuning, if m < 0, it is judged as a negative deviation. The current signal peak is lower than the left endpoint, and the deviation ratio K = [(Pref - Poff) - Pmax] / (Pref - Poff). Then, the tuning is performed according to the time priority strategy of ramp-up integration.

[0074] Calculate the variable step size r, r = K / (Ni).

[0075] Priority tuning integral time ,

[0076] Current tuning integral time Multiply by (1+r) to get the tuned integration time, and use the tuned integration time as the current integration time. ;

[0077] Points Time Tuning to the adjustable lower limit of integral time When the LD power is adjusted, the tuning count is reset.

[0078] Current signal peak value P max Multiply by (1+r) to get the peak value of the tuned signal, and use the peak value of the tuned signal as the current peak value of the signal, P max = P max ×(1+r)

[0079] Within the upper limit N of the tuning number (i≤N), if the current signal peak value P max If the signal peak value is within the target power range, the tuning is successful, the tuning ends, and the tuning count is reset; if the current signal peak value P max If the target power range is still within, continue tuning until the number of tunings exceeds the upper limit N (i>N), then stop tuning, reset the number of tunings, and output an alarm signal.

[0080] If m > 1, it is judged as a positive deviation, the current signal peak is higher than the right endpoint, and the deviation ratio K = [Pmax - (Pref + Poff)] / (Pref + Poff); then the tuning is performed according to the power reduction priority strategy.

[0081] Calculate the variable step size r, r = K / (Ni).

[0082] Priority tuning signal peak P max ,

[0083] Current signal peak value P max Multiply by (1-r) to get the peak value of the tuned signal, and use the peak value of the tuned signal as the current peak value of the signal, P max = P max ×(1-r)

[0084] Within the upper limit N of the tuning number (i≤N), if the current signal peak value P max If the signal peak value is within the target power range, the tuning is successful, the tuning ends, and the tuning count is reset; if the current signal peak value P max If the target power range is still within, continue tuning until the number of tunings exceeds the upper limit N (i>N), then stop tuning, reset the number of tunings, and output an alarm signal.

[0085] Current signal peak value P max Tune to the adjustable lower limit of transmit power When, then tune the integral time. At the same time, the tuning count is reset.

[0086] Current tuning integral time Multiply by (1-r) to get the tuned integration time, and use the tuned integration time as the current integration time. ;

[0087] Before each tuning, the deviation state judgment coefficient m and deviation ratio K need to be recalculated.

[0088] When the number of tunings exceeds the upper limit N of the number of tunings, if the current signal peak value Above the upper limit of the adaptive range Furthermore, the laser's emission power has been reduced to its adjustable lower limit. The points accumulation time has been reduced to its adjustable lower limit. At time, or current signal peak Below the lower limit of the adaptive range Furthermore, the points accumulation time has been increased to its current adjustable limit. The transmission power has been increased to its adjustable upper limit. If the system exceeds its adaptive capability, it will either maintain the current parameters or output an alarm signal.

[0089] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any way, and all technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A wide-range adaptive optical power tuning method suitable for triangulation systems, characterized in that, Includes the following steps: S1. Obtain the signal characteristic parameters of the triangulation system, wherein the signal characteristic parameters include saturation power and noise power; S2. The triangulation system sets an adaptive range based on saturation power and noise power. S3. Collect the current signal peak value and determine whether the current signal peak value is greater than the noise power; S4. If the current signal peak value is greater than the noise power, it is a valid signal. Perform the first tuning step, compare the current signal peak value with the adaptive range, and perform the following operations based on the comparison result: If the current signal peak value is higher than the upper limit of the adaptive range, the laser's emission power and the image sensor's integration time are tuned according to the first priority order to make the signal peak value fall within the adaptive range. The first priority order is: first reduce the laser's emission power, and then reduce the integration time when the emission power reaches the adjustable lower limit. If the current signal peak is lower than the lower limit of the adaptive range, the laser's emission power and the image sensor's integration time are tuned according to the second priority order so that the signal peak falls within the adaptive range. The second priority order is: first increase the integration time, and then increase the transmission power when the integration time reaches the current adjustable limit; Furthermore, in the first tuning step, the tuning amount of any parameter is determined according to a preset variable step strategy. The variable step strategy includes: calculating the deviation state judgment coefficient and deviation ratio of the current signal peak relative to the corresponding limit of the target power range; calculating the variable step according to the deviation ratio and the number of tuning steps; and performing tuning according to the variable step.

2. The method according to claim 1, characterized in that, Obtaining saturation power specifically involves increasing the laser's emission power in fixed steps until the signal peak reaches a preset saturation threshold, and then recording the emission power at this point as the saturation power. Obtaining noise power specifically involves: setting the laser's emission power to the minimum, acquiring and recording the signal peak value multiple times with the same integration time, and taking the maximum value of the signal peak value as the noise power.

3. The method according to claim 1, characterized in that, S2 specifically includes: Calculate reference point Reference point This is the midpoint between saturation power and noise power; Based on reference point and the preset adaptive interval half width Set the adaptive interval as .

4. The method according to claim 1, characterized in that, In step S3, if the current signal peak value is not greater than the noise power, then step S3 is repeated and continues to be executed within a preset time. If the signal peak value is not greater than the noise power within the preset time, then it is determined that there is no valid signal, and the current parameters are maintained or an alarm signal is issued.

5. The method according to claim 1, characterized in that, In step S4, the current adjustable upper limit of the integration time is constrained by the current sampling frequency of the triangulation system; if the current sampling frequency is higher than the preset frequency threshold, no integration time tuning is performed; the preset frequency threshold is 50kHz.

6. The method according to claim 1, characterized in that, In S4, after each tuning, a preset response stabilization time is waited before the signal peak value is re-acquired and the next round of judgment and tuning is performed.

7. The method according to claim 1, characterized in that, The deviation state judgment coefficient m 。 8. The method according to claim 7, characterized in that, In the variable stepping strategy Preset maximum number of tuning times N; Before tuning, calculate the deviation state judgment coefficient m. . The deviation state judgment coefficient m is calculated based on the current signal peak value. When 0≤m≤1, no tuning is needed, and monitoring continues; When m < 0 or m > 1, tuning is required. During tuning, if m < 0, it is judged as a negative deviation. The current signal peak is lower than the left endpoint, and the deviation ratio K = [(Pref - Poff) - Pmax] / (Pref - Poff). Then, the tuning is performed according to the time priority strategy of ramp-up integration. Calculate the variable step size r, r = K / (Ni); Priority tuning integral time , Points Time Tuning to the adjustable lower limit of integral time If this happens, the LD power is tuned, and the tuning count is reset. Current signal peak value P max Multiply by (1+r) to get the peak value of the tuned signal, and use the peak value of the tuned signal as the current peak value of the signal, P max = P max ×(1+r) Within the upper limit N of the tuning number (i≤N), if the current signal peak value P max If the signal peak value is within the target power range, the tuning is successful, the tuning ends, and the tuning count is reset; if the current signal peak value P max If the target power range is still within, continue tuning until the number of tuning times exceeds the upper limit N (i>N), then stop tuning, reset the number of tuning times, and output an alarm signal; If m > 1, it is judged as a positive deviation, the current signal peak is higher than the right endpoint, and the deviation ratio K = [Pmax - (Pref + Poff)] / (Pref + Poff); then the tuning is performed according to the power reduction priority strategy. Calculate the variable step size r, r = K / (Ni); Priority tuning signal peak P max P max = P max ×(1-r) Within the upper limit N of the tuning number (i≤N), if the current signal peak value P max If the signal peak value is within the target power range, the tuning is successful, the tuning ends, and the tuning count is reset; if the current signal peak value P max If the target power range is still within, continue tuning until the number of tuning times exceeds the upper limit N (i>N), then stop tuning, reset the number of tuning times, and output an alarm signal; Current signal peak value P max Tune to the adjustable lower limit of transmit power When, then tune the integral time. At the same time, the tuning count is reset; Current tuning integral time Multiply by (1-r) to get the tuned integration time, and use the tuned integration time as the current integration time. ; Before each tuning, the deviation state judgment coefficient m and deviation ratio K need to be recalculated.

9. The method according to claim 8, characterized in that, In S4, when the number of tuning times exceeds the upper limit N of the number of tuning times, if the current signal peak value is higher than the upper limit of the adaptive range and the laser's emission power has dropped to its adjustable lower limit and the integration time has dropped to its adjustable lower limit, or if the current signal peak value is lower than the lower limit of the adaptive range and the integration time has increased to its current adjustable upper limit and the emission power has increased to its adjustable upper limit, it is determined that the system's adaptive capability range has been exceeded, and the current parameters are maintained or an alarm signal is output.

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