Welding head contact detection method, contact detection device and welding equipment

Abstract

The present invention relates to the technical field of semiconductor packaging equipment, and more particularly to a soldering pin contact detection method, contact detection device, and soldering equipment. The present invention applies a target excitation signal to an ultrasonic transducer to sample a response signal generated by the ultrasonic transducer in response to the target excitation signal to obtain a first feedback signal, and then determines whether the soldering pin contacts the soldering position based on the first feedback signal. Compared to the encoder-based contact detection method in the prior art, the first feedback signal does not need to be transmitted between multiple mechanical mechanisms, effectively shortening the time required to obtain the first feedback signal. Based on the first feedback signal, a quick determination of whether the soldering pin contacts the soldering position can be made, thereby reducing detection delay.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor packaging equipment, and in particular to a welding head contact detection method, a contact detection device and welding equipment. Background Art

[0002] In the welding process, accurate identification of contact points is a key factor in ensuring welding quality and process stability. Currently, the mainstream contact detection methods are those based on encoders or current feedback.

[0003] However, contact detection methods based on encoders or current feedback have inherent delays. For example, in encoder-based contact detection methods, the bond head and bond head encoder are connected through a mechanical structure. The force at the contact point must be transmitted to the motor side through structures such as couplings and sliders before it can be sensed by the encoder. This results in mechanical hysteresis and the rigid filtering effect of the detection system. At the same time, the judgment window or average filtering introduced at the algorithm level further exacerbates the response delay. Actual tests have shown that the contact moment detected by the detection system lags behind the actual contact moment by 1.5-2ms. This can cause problems such as inconsistent weld penetration depth, material deformation, or weld failure, severely limiting the application of welding equipment (such as wire bonders) in high-precision, high-response welding processes. Summary of the Invention

[0004] The embodiments of the present invention provide a welding head contact detection method, a contact detection device and a welding device to solve the problem of response delay in the existing welding head contact detection method.

[0005] A welding head contact detection method, comprising:

[0006] Controlling the excitation signal generating device to apply a target excitation signal to the ultrasonic transducer, and obtaining a response signal generated by the ultrasonic transducer in response to the target excitation signal;

[0007] Controlling the welding head driving mechanism to drive the welding head to move downward at a uniform speed toward the welding position, and continuously sampling the response signal according to a preset first time window during the uniform downward movement to obtain a first feedback signal;

[0008] Comparing the first feedback signal with a pre-established baseline to determine whether the welding head meets the contact condition;

[0009] If the welding head meets the contact conditions, determine the welding position where the welding head contacts the welding;

[0010] If the welding head does not meet the contact condition, return to the execution control head driving mechanism to drive the welding head to the welding position at a uniform speed, and continuously sample the response signal according to the preset first time window during the uniform speed downward movement to obtain the first feedback signal step.

[0011] The above welding head contact detection method may optionally include controlling the excitation signal generating device to apply a target excitation signal to the ultrasonic transducer to obtain a response signal generated by the ultrasonic transducer in response to the target excitation signal;

[0012] The baseline is obtained as follows:

[0013] The response signal is sampled according to the second time window to obtain a second feedback signal; the second feedback signal is obtained by sampling the response signal of the ultrasonic transducer before the baseline is established, and the first feedback signal is obtained by sampling the response signal of the ultrasonic transducer after the baseline is established;

[0014] The second feedback signal is processed according to a preset signal processing algorithm to obtain a baseline. The signal processing algorithm includes an average filtering algorithm, a median filtering algorithm, or a sliding weighted algorithm.

[0015] The above-mentioned welding head contact detection method may optionally compare the first feedback signal with a pre-established baseline to determine whether the welding head meets the contact condition, including:

[0016] Obtaining the maximum amplitude and the minimum amplitude of the first feedback signal, and a reference value corresponding to the reference line;

[0017] Calculating a first difference between the maximum amplitude and the reference value, and a second difference between the minimum amplitude and the reference value;

[0018] respectively determining whether the first difference and the second difference are greater than a preset difference threshold;

[0019] If the first difference and / or the second difference is greater than the difference threshold, it is determined that the welding joint meets the contact condition.

[0020] In the above-mentioned welding head contact detection method, optionally, the first feedback signal includes a main signal and an auxiliary signal, and the reference line includes a main reference line and an auxiliary reference line;

[0021] The first feedback signal is compared with a pre-established baseline to determine whether the welding head meets the contact conditions, including:

[0022] Compare the main signal with the main baseline to determine whether the welding head meets the candidate conditions;

[0023] If the welding head meets the candidate conditions, the auxiliary signal is compared with the auxiliary baseline to determine whether the welding head meets the contact conditions;

[0024] If the welding head does not meet the candidate conditions, return to the execution control head driving mechanism to drive the welding head to the welding position at a uniform speed, and continuously sample the response signal according to the preset first time window during the uniform speed downward movement to obtain the first feedback signal step.

[0025] The above-mentioned welding head contact detection method optionally compares the first feedback signal with a pre-established baseline to determine whether the welding head meets the contact condition, including:

[0026] Construct a trigger line according to the preset trigger threshold and baseline;

[0027] determining whether the first feedback signal exceeds a trigger line during a rising and / or falling process;

[0028] If the first feedback signal exceeds the trigger line during the rising and / or falling process, it is determined that the welding head meets the contact condition;

[0029] If the first feedback signal does not exceed the trigger line during the rising and / or falling process, the step of returning to the execution control step of controlling the welding head driving mechanism to drive the welding head to move downward toward the welding position at a uniform speed, and continuously sampling the response signal according to the preset first time window during the uniform downward movement to obtain the first feedback signal.

[0030] The above-mentioned welding head contact detection method may optionally further include: after the first feedback signal exceeds the trigger line during the rising and / or falling process, and before determining that the welding head meets the contact condition:

[0031] Determining whether the first feedback signal continuously exceeds the trigger line for a period exceeding a preset first period;

[0032] If the first feedback signal exceeds the trigger line for a period exceeding a preset first period, it is determined that the welding head meets the contact condition;

[0033] If the first feedback signal continues to exceed the trigger line for a period of time that does not exceed the preset first period of time, the process returns to the execution step of controlling the welding head driving mechanism to drive the welding head to move downward toward the welding position at a uniform speed. During the uniform downward movement, the response signal is continuously sampled according to the preset first time window to obtain the first feedback signal.

[0034] In the above-mentioned welding head contact detection method, optionally, the trigger threshold includes a first trigger threshold and a second trigger threshold, and the first trigger threshold is smaller than the second trigger threshold;

[0035] Construct trigger lines based on preset trigger thresholds and baselines, including:

[0036] constructing a first trigger line based on the first trigger threshold and the baseline;

[0037] A second trigger line is constructed based on the second trigger threshold and the reference line.

[0038] The above welding head contact detection method may optionally determine whether the first feedback signal exceeds the trigger line during the rising and / or falling process, including:

[0039] determining whether the first feedback signal continuously exceeds the first trigger line and the second trigger line during the rising and / or falling process;

[0040] If the first feedback signal continuously exceeds the first trigger line and the second trigger line during the rising and / or falling process, determining whether the duration for which the first feedback signal continuously exceeds the first trigger line exceeds a preset second duration;

[0041] If the first feedback signal exceeds the first trigger line for a period of time exceeding a second period of time, it is determined that the welding head meets the contact condition;

[0042] If the first feedback signal continues to exceed the first trigger line for a period of time but does not exceed the second period of time, the process returns to the execution control step of driving the welding head to drive the welding head to move downward toward the welding position at a uniform speed, and continuously samples the response signal according to the preset first time window during the uniform downward movement to obtain the first feedback signal.

[0043] A contact detection device includes a processor and any of the above-mentioned excitation signal generating devices, ultrasonic transducers, bond head driving mechanisms and welding bond heads. The processor controls the excitation signal generating device, ultrasonic transducers, bond head driving mechanisms and welding bond heads to implement any of the above-mentioned welding bond head contact detection methods.

[0044] A welding device is characterized in that the welding device comprises the above-mentioned contact detection device.

[0045] An embodiment of the present invention provides a welding head contact detection method, a contact detection device and a welding equipment, which controls an excitation signal generating device to apply a target excitation signal to an ultrasonic transducer to obtain a response signal generated by the ultrasonic transducer in response to the target excitation signal; controls a head driving mechanism to drive the welding head to descend toward a welding position at a uniform speed, and continuously samples the response signal according to a preset time window during the uniform downward movement to obtain a first feedback signal; compares the first feedback signal with a pre-constructed baseline to determine whether the welding head meets the contact condition; if the welding head meets the contact condition, determines that the welding head contacts the welding position; if the welding head does not meet the contact condition, returns to the step of controlling the head driving mechanism to drive the welding head to descend toward the welding position at a uniform speed, and samples the response signal according to a preset time window during the uniform downward movement to obtain a first feedback signal. It can be seen that the present invention applies a target excitation signal to the ultrasonic transducer to sample the response signal generated by the ultrasonic transducer in response to the target excitation signal to obtain a first feedback signal, and then judges whether the welding head contacts the welding position based on the first feedback signal. Compared with the encoder-based contact detection method in the prior art, the first feedback signal does not need to be transmitted between multiple mechanical mechanisms, which can effectively shorten the time to obtain the first feedback signal, and then quickly make a judgment on whether the welding head contacts the welding position based on the first feedback signal, thereby achieving the purpose of reducing detection delay. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0047] Figure 1 This is a flow chart of an implementation of a welding head contact detection method disclosed in one embodiment of the present invention;

[0048] Figure 2 This is another implementation flow chart of a welding head contact detection method disclosed in one embodiment of the present invention;

[0049] Figure 3 This is another implementation flow chart of a welding head contact detection method disclosed in one embodiment of the present invention;

[0050] Figure 4 This is another implementation flow chart of a welding head contact detection method disclosed in one embodiment of the present invention;

[0051] Figure 5 is a schematic diagram of a trigger line disclosed in one embodiment of the present invention;

[0052] Figure 6 This is another implementation flow chart of a welding head contact detection method disclosed in one embodiment of the present invention;

[0053] Figure 7 This is a partial implementation flow chart of a welding head contact detection method disclosed in one embodiment of the present invention;

[0054] Figure 8 This is another implementation flow chart of a welding head contact detection method disclosed in one embodiment of the present invention;

[0055] Figure 9 This is another implementation flow chart of a welding head contact detection method disclosed in one embodiment of the present invention;

[0056] Figure 10 It is a structural schematic diagram of a contact detection device disclosed in one embodiment of the present invention. DETAILED DESCRIPTION

[0057] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0058] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0059] It will also be understood that the term "and / or" used in the present description and appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0060] As used in the present specification and the appended claims, the term "if" may be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" may be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0061] In addition, in the description of the present specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0062] References to "one embodiment" or "some embodiments" in the present specification mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in one or more embodiments of the present invention. Thus, phrases such as "in one embodiment," "in some embodiments," "in other embodiments," and "in yet other embodiments" appearing in various places in this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically stated. The terms "including," "comprising," "having," and variations thereof mean "including but not limited to," unless otherwise specifically stated.

[0063] The present invention provides a welding head contact detection method, a contact detection device and a welding equipment. The method comprises the following steps: applying a target excitation signal to an ultrasonic transducer by controlling an excitation signal generating device, obtaining a response signal generated by the ultrasonic transducer in response to the target excitation signal; controlling a head driving mechanism to drive the welding head to descend toward a welding position at a uniform speed, continuously sampling the response signal according to a preset time window during the uniform speed descending process, and obtaining a first feedback signal; comparing the first feedback signal with a pre-constructed baseline to determine whether the welding head meets a contact condition; if the welding head meets the contact condition, determining that the welding head contacts the welding position; and if the welding head does not meet the contact condition, returning to the step of controlling the head driving mechanism to drive the welding head to descend toward the welding position at a uniform speed, sampling the response signal according to a preset time window during the uniform speed descending process, and obtaining the first feedback signal. It can be seen that the present invention applies a target excitation signal to the ultrasonic transducer to sample the response signal generated by the ultrasonic transducer in response to the target excitation signal to obtain a first feedback signal, and then determines whether the welding head is in contact with the welding position based on the first feedback signal. Compared with the contact detection method based on the encoder in the prior art, the first feedback signal does not need to be transmitted between multiple mechanical mechanisms, which can effectively shorten the time to obtain the first feedback signal. Then, based on the first feedback signal, a quick judgment is made as to whether the welding head is in contact with the welding position, thereby achieving the purpose of reducing detection delay. In addition, in this embodiment, by continuously sampling the response signal according to a preset time window to obtain the first feedback signal, it is possible to continuously detect the process of the welding head dropping at a uniform speed and determine the real-time nature of the detection result. The following is an illustration of the specific embodiment.

[0064] In one embodiment, Figure 1 As shown, this embodiment discloses a method for detecting contact of a welding head. The method is applicable to welding equipment equipped with a welding head, such as a wire bonding machine, and specifically includes the following steps:

[0065] S101: controlling an excitation signal generating device to apply a target excitation signal to an ultrasonic transducer, and obtaining a response signal generated by the ultrasonic transducer in response to the target excitation signal.

[0066] In an optional implementation, the ultrasonic transducer in this embodiment is not limited to any one of a standard transverse vibration transducer, a longitudinal vibration transducer, a surface wave transducer, or a nonlinear resonant transducer. The technical purpose of applying a target excitation signal to the ultrasonic transducer is to detect whether the welding head contacts the welding position, rather than to cause the welding head to perform welding processing. Therefore, the target excitation signal can be a low-power excitation signal. For example, the power of the target excitation signal can be between 1% and 5% of the welding power. For example, taking the welding power of the wire bonding machine as 50W, according to the ratio of 1%, the power of the target excitation signal is 0.5W. The specific power of the target excitation signal is not limited in this embodiment. It is understandable that applying a low-power target excitation signal to the ultrasonic transducer will not produce a welding effect on the welding head, but it can achieve contact detection of the welding head.

[0067] In an optional implementation, the excitation signal generating device in this embodiment can be an ultrasonic driver or a signal device composed of a low-power oscillator and an amplifier. When the excitation signal generating device in this embodiment is an ultrasonic driver, the ultrasonic driver is one of the core components of the wire bonding machine. The method in this embodiment can be deployed on the wire bonding machine without modifying the wire bonding machine, which can effectively reduce the development cost of the wire bonding machine.

[0068] In an optional implementation, the excitation signal generating device in this embodiment can simultaneously operate a PLL (phase-locked loop) when outputting the target excitation signal to lock the resonant frequency of the target excitation signal, thereby significantly improving the stability, accuracy and anti-interference ability of the target excitation signal.

[0069] In an optional implementation, the target excitation signal in this embodiment includes, but is not limited to, a constant frequency excitation signal and a swept frequency excitation signal. The frequency of the target excitation signal can be set close to the resonance point of the ultrasonic transducer, or scanned within a specific frequency range, which is conducive to enhancing the sensitivity of the first feedback signal subsequently obtained. In addition, the target excitation signal in this embodiment can be any one of a continuous sine wave, a pulse train, a short-period burst signal, or a modulated waveform, which is conducive to matching the response characteristics of different types of ultrasonic transducers. In this embodiment, there is no limitation on the frequency, signal type, and waveform type of the target excitation signal.

[0070] In an optional implementation, in this embodiment, after the target excitation signal is applied to the ultrasonic transducer by controlling the excitation signal generating device, the ultrasonic transducer will respond to the target excitation signal to generate multiple response signals, including but not limited to one or more signals such as voltage signal, current signal, phase signal, resonant frequency, impedance amplitude, mutation slope (dφ / dt, df / dt), multi-point fitting residual, sliding window trend change, and power absorption. The response signal is not limited in this embodiment.

[0071] S102: Control the welding head driving mechanism to drive the welding head to move downward toward the welding position at a uniform speed. During the uniform downward movement, the response signal is continuously sampled according to a preset time window to obtain a first feedback signal.

[0072] In an optional implementation, this embodiment can synchronously and continuously sample one or more signals including voltage signals, current signals, phase signals, resonant frequency, impedance amplitude, and power absorption. The more signals that need to be sampled, the more first feedback signals are obtained. The more first feedback signals there are, the more contact detection needs to be performed based on each first feedback signal.

[0073] In an optional implementation, this embodiment can continuously sample the response signal through a high-frequency sampling ADC, or use a digital phase-locked loop (PLL) or phase detection module inside an existing driver to extract signal features from the response signal, thereby adapting to different hardware architectures of the ultrasonic transducer. The method for sampling the response signal in this embodiment is not limited.

[0074] As an extension, this embodiment can also use the acceleration, charge and impact response of the welding head at the moment of contact as response signals. The acceleration, charge and impact response of the welding head at the moment of contact are detected by integrating a piezoelectric sheet or MEMS sensor on the ultrasonic transducer structure, and the detected acceleration, charge and impact response are used as the first feedback signal, and then the contact detection of the welding head is performed based on the first feedback signal.

[0075] In an optional implementation, the bond head driving mechanism in this embodiment includes but is not limited to any one of a motor and encoder driving mechanism, a piezoelectric driving mechanism, a magnetic levitation driving mechanism, etc., as long as it has the ability to move downward at a controlled uniform speed. The specific structure of the bond head driving mechanism is not limited in this embodiment.

[0076] In an optional implementation, the welding header in this embodiment includes but is not limited to any one of a traditional ball welding header, a wedge welding header, a hanging header, a dual-transducer header, and a multi-wire welded composite structure header, etc. The specific structure of the welding header is not limited in this embodiment.

[0077] In an optional implementation, the embodiment can first control the welding head driving mechanism to move the welding head to the lowering position, and then control the welding head driving mechanism to drive the welding head to lower toward the welding position at a uniform speed at the lowering position. During the uniform lowering process, the response signal is continuously sampled according to a preset time window to obtain a first feedback signal. In other words, a first feedback signal is sampled in each time window. The length of the time window can be 3ms, 5ms, or 10ms, etc., and the specific length of the time window is not limited in this embodiment.

[0078] For example, taking the length of the time window as 10ms, the response signal generated by the ultrasonic transducer in 1-10ms is sampled according to the time window to obtain the first first feedback signal, and then the response signal generated by the ultrasonic transducer in 11-20ms is sampled according to the time window to obtain the second first feedback signal, and so on. It is possible to continuously sample the response signal according to the preset time window to obtain the first feedback signal.

[0079] It should be noted that, in this embodiment, after the excitation signal generating device is controlled to apply the target excitation signal to the ultrasonic transducer, the response signal can be continuously sampled according to the preset time window to obtain the first feedback signal. It is not necessary to start sampling the response signal when the welding head driving mechanism is controlled to drive the welding head to move downward at a uniform speed toward the welding position. In this embodiment, there is no limit on the start time of sampling.

[0080] S103: Compare the first feedback signal with a pre-established baseline to determine whether the welding head meets the contact condition.

[0081] In an optional implementation, the baseline in this embodiment can be set manually, for example, by inputting a baseline value corresponding to the baseline through a control page of a control system of the welding equipment, and then generating a corresponding baseline based on the baseline value. Then, after obtaining the first feedback signal, the first feedback signal is compared with the pre-established baseline to determine whether the welding head meets the contact condition. It should be noted that when multiple response signals are sampled simultaneously to obtain multiple first feedback signals, since the response signals sampled by different first feedback signals are different, there are significant differences between the different first feedback signals, and it is necessary to set a corresponding baseline value and baseline for each first feedback signal.

[0082] In an optional implementation, in this embodiment, before the welding head contacts the welding position, the response signal can be sampled to obtain a second feedback signal for processing to construct a baseline. The method for processing the second feedback signal includes but is not limited to any one of an average filtering algorithm, a median filtering algorithm, or a sliding weighted algorithm. The second feedback signal is processed by any one of an average filtering algorithm, a median filtering algorithm, or a sliding weighted algorithm to obtain a reference value corresponding to the second feedback signal, and then a baseline is constructed based on the reference value. For example, taking average filtering as an example, the second feedback signal is averaged and filtered to obtain the average value of the second feedback signal, and the straight line corresponding to the average value is determined in the time domain coordinate system as the baseline. The second feedback signal is obtained by sampling the response signal of the ultrasonic transducer before the baseline is constructed, and the first feedback signal is obtained by sampling the response signal of the ultrasonic transducer after the baseline is constructed.

[0083] In a specific implementation, in this embodiment, the maximum amplitude and minimum amplitude of the first feedback signal can be obtained, and then the difference between the maximum amplitude and the minimum amplitude and the baseline value of the baseline (such as the above-mentioned average value) is calculated, and it is judged whether the difference is greater than the preset difference threshold. When the difference is greater than the difference threshold, it is determined that the welding head meets the contact condition.

[0084] As an extension, this embodiment can also utilize a pre-established welding head contact detection model. The first feedback signal and a pre-established baseline can be input into the welding head contact detection model to obtain a welding head contact detection result. In this embodiment, feature vectors of signals such as the phase signal, frequency signal, current signal, and power signal can be extracted from the first feedback signal, so that the welding head contact detection model outputs the welding head contact detection result based on the extracted feature vectors. The welding head contact detection model can include, but is not limited to, models trained using a decision tree model, a neural network model, or a support vector machine.

[0085] It can be understood that in this embodiment, a corresponding welding head contact detection model can be constructed for each first feedback signal, and the welding head contact detection result corresponding to each first feedback signal can be obtained. Then, based on all the welding head contact detection results, the final result is determined. For example, all the welding head contact detection results represent the welding head contact welding position, then the welding head contact welding position is determined, or any welding head contact detection result represents the welding head contact welding position, then the welding head contact welding position is determined, or, the number of welding head contact detection results that represent the welding head contact welding position exceeds a preset number, then the welding head contact welding position is determined. No specific limitation is made in this embodiment.

[0086] S104: If the welding head meets the contact condition, determine the welding position where the welding head contacts the welding head.

[0087] If the welding head meets the contact condition, it is determined that the welding head contacts the welding position; if the welding head does not meet the contact condition, it means that the welding head has not yet contacted the welding position. Therefore, it is necessary to detect the first feedback signal that is continuously obtained, that is, return to execute the control head driving mechanism to drive the welding head to the welding position at a uniform speed, and continuously sample the response signal according to the preset time window during the uniform speed downward movement to obtain the first feedback signal. That is, return to execute step S102 and subsequent steps.

[0088] In a specific implementation, in this embodiment, the control process of steps S101 to S105 described above can be implemented by a main control processor of the welding equipment, wherein the main control processor includes, but is not limited to, any one of a digital signal processor (DSP), a field programmable gate array (FPGA), a microcontroller unit (MCU), or a system-on-chip (SoC) platform. When it is determined that the welding head has contacted the welding position, the excitation signal generating device stops applying the target excitation signal to the ultrasonic transducer. In other words, the excitation signal generating device will only apply the target excitation signal to the ultrasonic transducer for contact detection during the contact detection phase. Then, the main control processor can control the ultrasonic driver to drive the welding head to perform welding processing on the welding position (e.g., the inner lead of a semiconductor device placed at the welding position).

[0089] It should be noted that when multiple response signals are sampled simultaneously to obtain multiple first feedback signals, contact detection needs to be performed based on each first feedback signal and the corresponding baseline. When it is determined based on any one of the first feedback signals that the welding head meets the contact condition, the welding head is determined to be in contact with the welding position. Alternatively, when the number of welding heads that meet the contact condition reaches a preset number based on the first feedback signals, the welding head is determined to be in contact with the welding position. Alternatively, when it is determined based on all the first feedback signals that the welding heads meet the contact condition, the welding head is determined to be in contact with the welding position. In this embodiment, the specific method for determining whether the welding head is in contact with the welding position when sampling multiple first feedback signals is not limited.

[0090] In summary, an embodiment of the present invention provides a welding head contact detection method, which controls an excitation signal generating device to apply a target excitation signal to an ultrasonic transducer to obtain a response signal generated by the ultrasonic transducer in response to the target excitation signal; controls a head driving mechanism to drive the welding head to descend toward a welding position at a uniform speed, and continuously samples the response signal according to a preset time window during the uniform downward movement to obtain a first feedback signal; compares the first feedback signal with a pre-constructed baseline to determine whether the welding head meets the contact condition; if the welding head meets the contact condition, determines that the welding head contacts the welding position; if the welding head does not meet the contact condition, returns to the step of controlling the head driving mechanism to drive the welding head to descend toward the welding position at a uniform speed, and samples the response signal according to a preset time window during the uniform downward movement to obtain a first feedback signal. It can be seen that the present invention applies a target excitation signal to the ultrasonic transducer to sample the response signal generated by the ultrasonic transducer in response to the target excitation signal to obtain a first feedback signal, and then judges whether the welding head contacts the welding position based on the first feedback signal. Compared with the encoder-based contact detection method in the prior art, the first feedback signal does not need to be transmitted between multiple mechanical mechanisms, which can effectively shorten the time to obtain the first feedback signal, and then quickly make a judgment on whether the welding head contacts the welding position based on the first feedback signal, thereby achieving the purpose of reducing detection delay.

[0091] In one embodiment, Figure 2 As shown, step S103 in the above embodiment can be implemented by the following steps:

[0092] S201: Acquire a maximum amplitude and a minimum amplitude of a first feedback signal, and a reference value corresponding to a reference line.

[0093] S202: Calculate a first difference between the maximum amplitude and the reference value, and a second difference between the minimum amplitude and the reference value.

[0094] S203: Determine whether the first difference and the second difference are greater than a preset difference threshold respectively.

[0095] If the first difference and / or the second difference is greater than the difference threshold, it is determined that the welding joint meets the contact condition.

[0096] Among them, the maximum amplitude and the minimum amplitude are used to reflect the severity of the fluctuation of the first feedback signal. The larger the maximum amplitude, the more severe the upward fluctuation of the first feedback signal, and the smaller the minimum amplitude, the more severe the downward fluctuation of the first feedback signal.

[0097] It is understandable that when the welding head contacts the welding position, the first feedback signal may fluctuate violently upward, downward, or both. Therefore, it is necessary to obtain the maximum and minimum amplitudes of the first feedback signal to determine whether the welding head meets the contact condition based on the first feedback signal from two directions.

[0098] To sum up, in this embodiment, by obtaining the maximum amplitude and minimum amplitude of the first feedback signal to judge from two directions whether the welding head meets the contact conditions, it can effectively adapt to the sampling of different response signals of the ultrasonic transducer to obtain the first feedback signal. That is to say, no matter which response signal is chosen to sample to obtain the first feedback signal during sampling, it can be realized to judge whether the welding head meets the contact conditions, thereby improving the applicability of the contact detection method in this application.

[0099] In one embodiment, Figure 3 As shown, the first feedback signal includes a main signal and an auxiliary signal, and the baseline includes a main baseline and an auxiliary baseline. On this basis, step S103 in this embodiment can be implemented by the following steps:

[0100] S301: Compare the main signal with the main baseline to determine whether the welding head meets the candidate conditions.

[0101] S302: If the welding head meets the candidate condition, the auxiliary signal is compared with the auxiliary reference line to determine whether the welding head meets the contact condition.

[0102] If the welding head does not meet the candidate conditions, return to the execution control head driving mechanism to drive the welding head to the welding position at a uniform speed, and continuously sample the response signal according to the preset first time window during the uniform speed downward movement to obtain the first feedback signal step.

[0103] It will be appreciated that in this embodiment, different first feedback signals are divided into primary signals and auxiliary signals. For example, taking the corresponding signals including a frequency signal and a current signal as an example, the frequency signal and the current signal are sampled according to a preset time window to obtain a first feedback signal corresponding to the frequency signal and a first feedback signal corresponding to the current signal. The first feedback signal corresponding to the frequency signal is used as the primary signal, and the first feedback signal corresponding to the current signal is used as the auxiliary signal.

[0104] In a specific implementation, in this embodiment, whether the welding head meets the contact condition is judged based on the main signal and the auxiliary signal respectively, wherein whether the welding head meets the candidate condition is judged based on the main signal and the main reference line first. If the welding head does not meet the candidate condition, there is no need to judge whether the welding head meets the contact condition based on the auxiliary signal and the auxiliary reference line, and re-judge whether the welding head meets the candidate condition based on the newly acquired first feedback signal, that is, return to the execution control head drive mechanism to drive the welding head to the welding position at a uniform speed, and continuously sample the response signal according to the preset first time window during the uniform speed downward movement to obtain the first feedback signal. If the welding head meets the candidate condition, then further judge whether the welding head meets the contact condition based on the auxiliary signal and the auxiliary reference line.

[0105] To sum up, in this embodiment, double judgment is used to determine whether the welding head meets the contact conditions, which avoids the situation where a single condition is accidentally triggered and causes misjudgment, which is beneficial to improving the robustness and versatility of the contact detection method in this embodiment. At the same time, by setting the main signal and the auxiliary signal, it avoids performing welding head contact detection based on all the first feedback signals each time, reduces the load on the computing power resources of the welding equipment, and is beneficial to improving the stability of the welding equipment.

[0106] In one embodiment, Figure 4 As shown, step S103 in this embodiment can also be implemented by the following steps:

[0107] S401: Constructing a trigger line according to a preset trigger threshold and a baseline.

[0108] In a specific implementation, in this embodiment, the trigger line can be constructed by moving the base line upward and / or downward according to the trigger threshold. It can be understood that the base line is moved upward according to the trigger threshold to construct a trigger line, or the base line is moved downward according to the trigger threshold to construct a trigger line, or the base line is moved upward and downward according to the trigger threshold respectively to construct two trigger lines. In this embodiment, the trigger line can be constructed upward and / or downward according to actual needs, which is not limited in this embodiment. Figure 5 As shown, a and b are two trigger lines, and c is the baseline.

[0109] S402: Determine whether the first feedback signal exceeds a trigger line during a rising and / or falling process.

[0110] If the first feedback signal exceeds the trigger line during the rising and / or falling process, it is determined that the welding head meets the contact condition; if the first feedback signal does not exceed the trigger line during the rising and / or falling process, the step of returning to execute the control of the head driving mechanism to drive the welding head to move downward toward the welding position at a uniform speed, and continuously sampling the response signal according to the preset first time window during the uniform downward movement to obtain the first feedback signal.

[0111] It can be understood that if the first feedback signal exceeds the trigger line during the rising and / or falling process, it is determined that the welding head meets the contact condition; if the first feedback signal does not exceed the trigger line during the rising and / or falling process, it is determined that the welding head does not meet the contact condition, and the contact judgment is re-performed based on the new first feedback signal obtained by sampling, that is, the execution control head driving mechanism is returned to drive the welding head to move downward at a uniform speed toward the welding position, and the response signal is continuously sampled according to the preset first time window during the uniform downward movement to obtain the first feedback signal.

[0112] In one embodiment, Figure 6 As shown, in this embodiment, after the first feedback signal exceeds the trigger line during the rising and / or falling process, before determining that the welding head meets the contact condition, the following steps may also be included:

[0113] S601: Determine whether the time period during which the first feedback signal exceeds the trigger line exceeds a preset first time period.

[0114] If the first feedback signal continues to exceed the trigger line for a period longer than a preset first period, it is determined that the welding head meets the contact condition.

[0115] If the first feedback signal continues to exceed the trigger line for a period of time that does not exceed the preset first period of time, the process returns to the execution step of controlling the welding head driving mechanism to drive the welding head to move downward toward the welding position at a uniform speed. During the uniform downward movement, the response signal is continuously sampled according to the preset first time window to obtain the first feedback signal.

[0116] It can be understood that when the first feedback signal exceeds the trigger line, if the time length that the first feedback signal continues to exceed the trigger line does not exceed the preset first time length, it means that the first feedback signal exceeds the trigger line due to occasional noise interference or occasional spike interference. At this time, it is considered that the welding head has not met the contact condition; if the time length that the first feedback signal continues to exceed the trigger line exceeds the preset first time length, the influence of noise interference or spike interference is eliminated, and it is determined that the welding head meets the contact condition.

[0117] To sum up, in this embodiment, by judging whether the time length during which the first feedback signal exceeds the trigger line exceeds the preset first time length, the influence of occasional noise interference or occasional spike interference on the welding head contact detection is eliminated, which is beneficial to improving the detection accuracy.

[0118] In one embodiment, Figure 7 As shown, the trigger threshold in this embodiment includes a first trigger threshold and a second trigger threshold, and the first trigger threshold is smaller than the second trigger threshold. On this basis, step S401 in the above embodiment can be implemented by the following steps:

[0119] S701: Constructing a first trigger line based on a first trigger threshold and a baseline.

[0120] S702: Constructing a second trigger line based on the second trigger threshold and the baseline.

[0121] It can be understood that when the trigger threshold includes a first trigger threshold and a second trigger threshold, a trigger line can be constructed based on the first trigger threshold and the baseline, and another trigger line can be constructed based on the second trigger threshold and the baseline, namely the first trigger line and the second baseline.

[0122] Specifically, in this embodiment, the baseline can be first moved upward and / or downward based on the first trigger threshold to construct a first trigger line; then the baseline can be moved upward and / or downward based on the second trigger threshold to construct a second trigger line, wherein the positions where the above two baselines start to move are both initial positions, that is, the construction of the first trigger line and the second trigger line are carried out separately, and the two construction processes do not affect each other.

[0123] On this basis, if Figure 8 As shown, step S402 in the above embodiment can be implemented by the following steps:

[0124] S801: Determine whether the first feedback signal continuously exceeds the first trigger line and the second trigger line during the rising and / or falling process;

[0125] S802: If the first feedback signal continuously exceeds the first trigger line and the second trigger line during the rising and / or falling process, determine whether the duration for which the first feedback signal continuously exceeds the first trigger line exceeds a preset second duration.

[0126] If the first feedback signal continues to exceed the first trigger line for a period longer than a second period, it is determined that the welding head meets the contact condition.

[0127] If the first feedback signal continues to exceed the first trigger line for a period of time but does not exceed the second period of time, the process returns to the execution control step of driving the welding head to drive the welding head to move downward toward the welding position at a uniform speed, and continuously samples the response signal according to the preset first time window during the uniform downward movement to obtain the first feedback signal.

[0128] It can be understood that the welding head is considered to meet the candidate condition only if the first feedback signal continuously exceeds the first trigger line and the second trigger line during the rising and / or falling process, and then it is judged whether the time period for which the first feedback signal continuously exceeds the first trigger line exceeds the preset second time period. That is, after the first feedback signal continuously exceeds the first trigger line and the second trigger line, it is not necessary for the first feedback signal to continuously exceed the second trigger line. As long as the time period for which the first feedback signal continuously exceeds the first trigger line exceeds the preset second time period, it can be determined that the welding head meets the contact condition; if the first feedback signal does not continuously exceed the first trigger line and the second trigger line, or the time period for which the first feedback signal continuously exceeds the first trigger line does not exceed the preset second time period, it is necessary to re-acquire the first feedback signal and re-perform contact detection based on the first feedback signal, that is, return to the step of executing the control of the head driving mechanism to drive the welding head to uniformly descend toward the welding position, and continuously sample the response signal according to the preset first time window during the uniform descending process to obtain the first feedback signal.

[0129] To sum up, in this embodiment, high and low dual trigger lines are set within the preset time window content, which can avoid repeated triggering of the first feedback signal at the trigger line boundary. At the same time, by judging whether the time length for which the first feedback signal continuously exceeds the first trigger line exceeds the preset first time length, the influence of occasional noise interference or occasional spike interference on the contact detection of the welding head can be eliminated, which is beneficial to improving the detection accuracy.

[0130] In one embodiment, Figure 9 As shown, after step S101, the baseline in this embodiment is obtained by:

[0131] S901: Sample the response signal according to the second time window to obtain a second feedback signal.

[0132] The second feedback signal is obtained by sampling the response signal of the ultrasonic transducer before the baseline is constructed, and the first feedback signal is obtained by sampling the response signal of the ultrasonic transducer after the baseline is constructed.

[0133] S902: Process the second feedback signal according to a preset signal processing algorithm to obtain a baseline.

[0134] The length of the second time window may be the same as or different from the length of the first time window, which is not limited in this embodiment.

[0135] Specifically, the signal processing algorithm in this embodiment includes but is not limited to any one of an average filtering algorithm, a median filtering algorithm or a sliding weighted algorithm. The second feedback signal is processed based on the signal processing algorithm to obtain a reference value corresponding to the second feedback signal, and then a baseline is constructed based on the reference value.

[0136] In summary, this embodiment constructs a baseline based on feedback signals. Compared to manually set baselines, this baseline ensures both representativeness and robustness to occasional interference. Furthermore, real-time determination of whether the welding head is in contact with the welding position based on this baseline can avoid false triggering or missed detections caused by differences in material reflectivity, fluctuations in transducer response, or changes in process parameters. This mechanism supports feedback parameter normalization and adaptive adjustment of the judgment window, offering high versatility and automated deployment capabilities, adapting to different materials, different welding structures, and various types of ultrasonic transducers.

[0137] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0138] In one embodiment, a contact detection device is provided, such as Figure 10 As shown, the device includes a processor and the excitation signal generating device, ultrasonic transducer, bonding head driving mechanism and welding bonding head described in any of the above embodiments. The processor controls the excitation signal generating device, ultrasonic transducer, bonding head driving mechanism and welding bonding head to implement the welding bonding head contact detection method described in any of the above embodiments. For example Figure 1 The soldering contact detection method shown, or Figures 2 to 8 To avoid repetition, it will not be described here.

[0139] In one embodiment, a welding device is provided. The welding device includes the contact detection device described in the above embodiment.

[0140] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A welding head contact detection method, characterized in that: include: controlling the excitation signal generating device to apply a target excitation signal to the ultrasonic transducer to obtain a response signal generated by the ultrasonic transducer in response to the target excitation signal; Controlling the welding head driving mechanism to drive the welding head to move downward at a uniform speed toward the welding position, and continuously sampling the response signal according to a preset first time window during the uniform speed moving downward to obtain a first feedback signal; Comparing the first feedback signal with a pre-established baseline to determine whether the welding head meets the contact condition; If the welding head meets the contact condition, determining that the welding head contacts the welding position; If the welding head does not meet the contact condition, returning to the step of controlling the head driving mechanism to drive the welding head to move downward at a uniform speed toward the welding position, and continuously sampling the response signal according to a preset first time window during the uniform downward movement to obtain a first feedback signal; wherein, after controlling the excitation signal generating device to apply the target excitation signal to the ultrasonic transducer and obtaining the response signal generated by the ultrasonic transducer in response to the target excitation signal; The baseline is obtained as follows: The response signal is sampled according to a second time window to obtain a second feedback signal; the second feedback signal is obtained by sampling the response signal of the ultrasonic transducer before the baseline is established, and the first feedback signal is obtained by sampling the response signal of the ultrasonic transducer after the baseline is established; Processing the second feedback signal according to a preset signal processing algorithm to obtain the baseline, wherein the signal processing algorithm includes an average filtering algorithm, a median filtering algorithm, or a sliding weighted algorithm; The first feedback signal is compared with a pre-established baseline to determine whether the welding head meets the contact condition, including: Obtaining a maximum amplitude and a minimum amplitude of the first feedback signal, and a reference value corresponding to the reference line; calculating a first difference between the maximum amplitude and the reference value, and a second difference between the minimum amplitude and the reference value; respectively determining whether the first difference and the second difference are greater than a preset difference threshold; If the first difference and / or the second difference is greater than the difference threshold, it is determined that the welding head meets the contact condition; Wherein, the first feedback signal includes a main signal and an auxiliary signal, and the reference line includes a main reference line and an auxiliary reference line; Comparing the first feedback signal with a pre-established baseline to determine whether the welding head meets the contact condition includes: Comparing the main signal with the main reference line to determine whether the welding head meets the candidate condition; If the welding head meets the candidate condition, the auxiliary signal is compared with the auxiliary reference line to determine whether the welding head meets the contact condition; If the welding head does not meet the candidate conditions, return to the execution step of controlling the head driving mechanism to drive the welding head to move downward toward the welding position at a uniform speed, and continuously sample the response signal according to a preset first time window during the uniform downward movement to obtain a first feedback signal.

2. The welding head contact detection method according to claim 1, characterized in that: Comparing the first feedback signal with a pre-established baseline to determine whether the welding head meets the contact condition includes: Constructing a trigger line according to a preset trigger threshold and the baseline; determining whether the first feedback signal exceeds the trigger line during a rising and / or falling process; If the first feedback signal exceeds the trigger line during the rising and / or falling process, it is determined that the welding head meets the contact condition; If the first feedback signal does not exceed the trigger line during the rising and / or falling process, the step of returning to the execution control step of controlling the welding head driving mechanism to drive the welding head to move downward toward the welding position at a uniform speed, and continuously sampling the response signal according to the preset first time window during the uniform downward movement to obtain the first feedback signal.

3. The welding head contact detection method according to claim 2, characterized in that: After the first feedback signal exceeds the trigger line during the rising and / or falling process, and before determining that the welding head meets the contact condition, the method further includes: Determining whether the first feedback signal continuously exceeds the trigger line for a period exceeding a preset first period; If the first feedback signal exceeds the trigger line for a period exceeding a preset first period, it is determined that the welding head meets the contact condition; If the first feedback signal continues to exceed the trigger line for a period of time that does not exceed the preset first period of time, return to the execution control step of controlling the welding head driving mechanism to drive the welding head to move downward toward the welding position at a uniform speed, and continuously sample the response signal according to the preset first time window during the uniform downward movement to obtain the first feedback signal.

4. The welding head contact detection method according to claim 2, characterized in that: The trigger threshold includes a first trigger threshold and a second trigger threshold, and the first trigger threshold is smaller than the second trigger threshold; Constructing a trigger line according to a preset trigger threshold and the baseline includes: constructing a first trigger line based on the first trigger threshold and the baseline; A second trigger line is constructed based on the second trigger threshold and the reference line.

5. The welding head contact detection method according to claim 4, characterized in that: Determining whether the first feedback signal exceeds the trigger line during the rising and / or falling process includes: determining whether the first feedback signal continuously exceeds the first trigger line and the second trigger line during a rising and / or falling process; If the first feedback signal continuously exceeds the first trigger line and the second trigger line during the rising and / or falling process, determining whether the time period for which the first feedback signal continuously exceeds the first trigger line exceeds a preset second time period; If the first feedback signal exceeds the first trigger line for a period longer than the second period, it is determined that the welding head meets the contact condition; If the first feedback signal continues to exceed the first trigger line for a period of time but does not exceed the second period of time, return to the execution control step of controlling the welding head driving mechanism to drive the welding head to move downward toward the welding position at a uniform speed, and continuously sample the response signal according to the preset first time window during the uniform downward movement to obtain the first feedback signal.

6. A contact detection device, characterized in that: The contact detection device includes a processor, an excitation signal generating device, an ultrasonic transducer, a bonding head driving mechanism and a welding bonding head. The processor controls the excitation signal generating device, the ultrasonic transducer, the bonding head driving mechanism and the welding bonding head to implement the welding bonding head contact detection method according to any one of claims 1 to 5.

7. A welding device, characterized in that: The welding equipment includes the contact detection device according to claim 6 above.

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