Field zero setting method and device for force sensor

Abstract

The invention discloses an on-site zero setting method and device for a force sensor, and belongs to the technical field of industrial control. The invention provides a force sensor field zeroing method, aiming at solving the technical problems that the operation is time-consuming, the process is complicated and the zeroing precision is low because the existing force sensor field zeroing depends on a hardware manual knob resistor. Firstly, an ADC module collects an initial output voltage value of a force sensor Wheatstone bridge and transmits the initial output voltage value to a control module; the control module calculates a difference value delta V with a target zero value and judges a preset interval to which the delta V belongs; the corresponding DAC adjustment step length is matched according to the interval; controlling the DAC module to output an adjusting voltage to a bridge compensation end; the steps of sampling, judging and adjusting are executed circularly until delta V is smaller than or equal to 0.0001 V, and zero setting is completed; and finally, the final adjustment voltage of the DAC is stored in the storage module. Software control replaces traditional hardware manual operation, equipment disassembly and assembly are not needed, zero setting time consumption is shortened, operation complexity is reduced, zero setting precision is improved through adaptive step length and closed-loop control, and the method is suitable for field calibration of force sensors in scenes of electronic weighing instruments, industrial control, material testing machines and the like.

Description

Technical Field

[0001] This application relates to the field of industrial control technology, and in particular to a method and apparatus for zeroing a force sensor in the field. Background Technology

[0002] In the fields of automation instrumentation and industrial control, force sensors are the core components for force measurement, and are widely used in scenarios such as weight detection in electronic scales, load monitoring of industrial equipment, and mechanical performance testing in material testing machines. Currently, most mainstream force sensors are based on the Wheatstone bridge structure design, which senses changes in external force through strain gauges, converts mechanical signals into electrical signals for output, and ultimately achieves quantitative detection of force values.

[0003] To ensure measurement accuracy, force sensors require on-site zeroing after installation to compensate for zero drift caused by installation errors, initial stress, and environmental interference. Traditional zeroing methods employ manual hardware adjustment: operators use a rotary potentiometer to change the resistance of the Wheatstone bridge arms. After each adjustment, the equipment must be disassembled and the sensor output current checked until the current is approximately zero, at which point zeroing is considered complete. However, this method has significant drawbacks: firstly, the zeroing process relies on the operator's feel, requiring repeated attempts and disassembly, with each zeroing cycle typically exceeding 30 minutes, resulting in high labor costs and low efficiency; secondly, the accuracy of manually adjusted resistance is limited by the potentiometer's resolution, making it difficult to achieve output accuracy at the 0.001V level, and resistance drift is easily caused by changes in ambient temperature, requiring frequent readjustment; furthermore, repeated disassembly and reassembly can loosen the sensor interface, further affecting measurement stability. Summary of the Invention

[0004] This application provides a method and apparatus for zeroing a force sensor in the field. The technical solution is as follows: On the one hand, a method for zeroing a force sensor in the field is provided, the method comprising: Step 1) Initial signal acquisition: Acquire the initial output voltage value of the force sensor's Wheatstone bridge through an analog-to-digital converter (ADC) module. and the Transmitted to the control module; Step 2) Difference calculation and interval determination: The control module will... The difference is calculated by performing a difference operation between the value and the target zero value V_target (where V_target is 0V ± 0.0001V). The system determines the preset difference range to which ΔV belongs, and the preset difference range includes ΔV > 1V, 0.1V < ΔV ≤ 1V, 0.01V < ΔV ≤ 0.1V, 0.001V < ΔV ≤ 0.01V, and 0.0001V < ΔV ≤ 0.001V. Step 3) Adaptive step size matching: The control module matches the corresponding digital-to-analog converter (DAC) and adjusts the step size S according to the preset difference range to which ΔV belongs: if ΔV > 1V, then S = 0.6V; if 0.1V < ΔV ≤ 1V, then S = 0.06V; if 0.01V < ΔV ≤ 0.1V, then S = 0.006V; if 0.001V < ΔV ≤ 0.01V, then S = 0.0006V; if 0.0001V < ΔV ≤ 0.001V, then S = 0.00006V. Step 4) Compensation voltage output: The control module sends a control command to the DAC module, causing the DAC module to output an adjustment voltage V_adjust corresponding to S, and loads V_adjust to the compensation terminal of the Wheatstone bridge to adjust the balance state of the Wheatstone bridge. Step 5) Accuracy verification and cyclic zeroing: Repeat steps 1) to 4), continuously collect the adjusted force sensor output voltage and calculate ΔV until ΔV ≤ 0.0001V, at which point the control module determines that the zeroing is complete; Step 6) Zeroing parameter storage: The control module stores the final adjustment voltage V_final of the DAC module after zeroing is completed into the storage module.

[0005] Optionally, in step 1), the ADC module acquires the... The method further includes: The output voltage of the force sensor Wheatstone bridge is subjected to low-pass filtering to remove power frequency noise and high-frequency interference signals.

[0006] Optionally, in step 4), the voltage direction of V_adjust is determined according to the... The relationship with the size of V_target is determined, and the determination method includes: like If so, the DAC module outputs a positive V_adjust; like Then the DAC module outputs an inverted V_adjust.

[0007] Optionally, the method further includes: The operating ambient temperature T of the force sensor is collected in real time through the temperature detection module; When the deviation ΔT between T and the reference temperature (25℃) is greater than ±5℃, the control module adjusts S according to the preset temperature-step correction coefficient. The temperature-step correction coefficient is such that for every 1℃ deviation of T from the reference temperature, S is corrected by ±0.00001V.

[0008] Optionally, in step 6), the storage module is a non-volatile memory. When the force sensor is powered on and started up again, the control module directly calls V_final stored in the storage module to perform initial compensation on the Wheatstone bridge without repeating the zeroing process.

[0009] On the other hand, a force sensor field zeroing system for implementing the above-described method is provided, including an ADC sampling module, a DAC output module, a control module, and a storage module; The input terminal of the ADC sampling module is electrically connected to the output terminal of the Wheatstone bridge of the force sensor, and the output terminal is electrically connected to the first input terminal of the control module, for acquiring the output voltage of the Wheatstone bridge and transmitting it to the control module; The input terminal of the DAC output module is electrically connected to the first output terminal of the control module, and the output terminal is electrically connected to the compensation terminal of the Wheatstone bridge, for receiving instructions from the control module and outputting an adjustment voltage; The storage module is electrically connected to the second output terminal of the control module and is used to store the final adjustment voltage V_final of the DAC output module; the control module is used to perform difference calculation, step size matching and cyclic zeroing logic.

[0010] Optionally, a temperature detection module is also included. The output of the temperature detection module is electrically connected to the second input of the control module. It is used to collect the operating ambient temperature T of the force sensor and transmit it to the control module for the control module to correct the DAC adjustment step size S.

[0011] Optionally, the sampling accuracy of the ADC sampling module is not less than 16 bits, and the resolution of the DAC output module is not less than 12 bits, in order to meet the requirement of zero-adjustment accuracy ≤ 0.0001V.

[0012] Optionally, the ADC sampling module has a built-in low-pass filter unit with a cutoff frequency of 10Hz, which is used to filter out 50Hz / 60Hz power frequency noise and high-frequency interference signals in the working environment of the force sensor.

[0013] This application discloses a method and apparatus for on-site zeroing of a force sensor, belonging to the field of industrial control technology. Addressing the technical problems of existing force sensor on-site zeroing methods that rely on manual rotary resistors, resulting in time-consuming operation, complex procedures, and low zeroing accuracy, this application provides a method for on-site zeroing of a force sensor. First, the initial output voltage value of the force sensor's Wheatstone bridge is acquired using an ADC module. And transmit it to the control module; the control module calculates. The difference ΔV between the target zero value and the target zero value is used to determine the preset range to which ΔV belongs; the corresponding DAC is matched and the step size is adjusted according to the range; the DAC module outputs the adjustment voltage to the bridge compensation terminal; the sampling, judgment, and adjustment steps are executed cyclically until ΔV ≤ 0.0001V to complete zeroing; finally, the final adjusted voltage of the DAC is stored in the storage module. Software control replaces traditional manual hardware operation, eliminating the need for equipment disassembly and assembly, shortening zeroing time, and reducing operational complexity. Simultaneously, adaptive step size and closed-loop control improve zeroing accuracy, making it suitable for on-site calibration of force sensors in scenarios such as electronic scales, industrial control, and material testing machines. Attached Figure Description

[0014] Figure 1 A flowchart of a field zeroing method for a force sensor is shown; Figure 2 A diagram showing the hardware signal interaction and step size control correspondence of a force sensor zeroing system is provided. Figure 3 A complete system structure diagram of field zeroing of a force sensor with temperature compensation is shown. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0016] In this article, "multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0017] Example 1 like Figure 1 The diagram shows a flowchart of a field zeroing method for a force sensor. This application provides a field zeroing method for a force sensor, the method comprising: Step 1, Initial signal acquisition: Acquire the initial output voltage value of the force sensor's Wheatstone bridge using an analog-to-digital converter (ADC) module. and will Transmitted to the control module.

[0018] A 16-bit precision ADC module (model: ADS1115, sampling rate 128SPS) was selected, and its input terminal was directly electrically connected to the output terminal of a strain gauge force sensor (based on a Wheatstone bridge design, measuring range 0-300kg). After the sensor was installed and powered on in the field, the ADC module acquired the initial output voltage of the Wheatstone bridge in real time, and after processing by the internal signal conditioning circuit, the initial voltage value was obtained. and through the I2C communication protocol Transmitted to the control module (model: STM32F103 microcontroller).

[0019] Compared to the shortcomings of traditional manual zeroing, which lacks precise initial signal acquisition, the 16-bit ADC module can achieve a sampling resolution of 0.00015V, accurately capturing the initial output state of the bridge, avoiding deviations in the subsequent zeroing direction due to initial signal errors, providing reliable starting data for the entire zeroing process, and solving the problem of blindly relying on experience to judge the zeroing direction in the traditional method.

[0020] Step 2, difference calculation and interval determination, the control module will The difference is calculated by performing a difference operation between the value and the target zero value V_target (V_target is 0V ± 0.0001V). It determines the preset difference range to which ΔV belongs. The preset difference range includes ΔV>1V, 0.1V<ΔV≤1V, 0.01V<ΔV≤0.1V, 0.001V<ΔV≤0.01V, and 0.0001V<ΔV≤0.001V.

[0021] The control module has a built-in difference calculation algorithm to calculate the received difference. The difference between the value and the preset target zero value V_target (0V ± 0.0001V) is calculated to obtain ΔV = |1.23V - 0V| = 1.23V. Then, the interval determination logic is called to compare the value with the preset five difference intervals (ΔV > 1V, 0.1V < ΔV ≤ 1V, 0.01V < ΔV ≤ 0.1V, 0.001V < ΔV ≤ 0.01V, 0.0001V < ΔV ≤ 0.001V). The result is determined to be within the interval "ΔV > 1V", and the determination result is sent to the step size matching unit.

[0022] By quantifying the difference and clearly defining the interval, the traditional manual zeroing method of "repeatedly trying and failing to find the zeroing direction" is replaced, so that the subsequent step size selection has a clear basis, avoiding the problems of "large adjustment with small steps (time-consuming)" or "small adjustment with large steps (overshoot)" caused by the ambiguity of the interval, and improving the rigor of the zeroing logic.

[0023] Step 3, adaptive step size matching: The control module matches the corresponding digital-to-analog converter (DAC) and adjusts the step size S according to the preset difference range to which ΔV belongs.

[0024] If ΔV > 1V, then S = 0.6V; if 0.1V < ΔV ≤ 1V, then S = 0.06V; if 0.01V < ΔV ≤ 0.1V, then S = 0.006V; if 0.001V < ΔV ≤ 0.01V, then S = 0.0006V; if 0.0001V < ΔV ≤ 0.001V, then S = 0.00006V.

[0025] The step size matching unit of the control module stores a preset "range-step size" correspondence table. After receiving the judgment result of "ΔV>1V", it automatically matches the corresponding DAC to adjust the step size S=0.6V and writes the step size value into the DAC control register, waiting for subsequent output instructions.

[0026] By adopting an adaptive strategy of "large steps for large differences and small steps for small differences", the zeroing efficiency is improved by more than 80% compared with a fixed step size (such as a fixed step size of 0.01V). If ΔV=1.2V, a fixed step size requires 120 adjustments, while an adaptive step size only requires 3-4 adjustments to approach the target value. At the same time, it avoids "over-adjustment and repetition" caused by large steps when the difference is small, thus balancing efficiency and accuracy.

[0027] Step 4: Compensation voltage output. The control module sends a control command to the DAC module, causing the DAC module to output an adjustment voltage V_adjust corresponding to S, and load V_adjust onto the compensation terminal of the Wheatstone bridge to adjust the balance state of the Wheatstone bridge.

[0028] The control module sends control commands to the 12-bit DAC module (model: DAC8552, output range 0-5V), the commands including "step S=0.6V" and "positive output" (because...). The parameters of the DAC module are as follows: After receiving the command, the DAC module converts the digital signal into a 0.6V analog voltage V_adjust, which is applied to the compensation terminal of the Wheatstone bridge through an adjustable current-limiting resistor (1kΩ, to avoid excessive current damaging the bridge). This changes the potential difference of the bridge arms, making the bridge output voltage closer to 0V.

[0029] By replacing the mechanical operation of the traditional "manual rotary resistor" with digital voltage regulation, voltage adjustment can be completed without disassembling the equipment casing, solving the problem of the complicated process of "disassembling and assembling the equipment every time adjustment is made" in the traditional method. At the same time, the DAC output accuracy can reach 0.0012V, which is far higher than the ±0.01V adjustment accuracy of the rotary resistor.

[0030] Step 5, accuracy verification and cyclic zeroing: Repeat steps 1) to 4), continuously collect the adjusted force sensor output voltage and calculate ΔV until ΔV≤0.0001V, at which point the control module determines that the zeroing is complete.

[0031] After the compensation voltage is applied, the ADC module again samples the output voltage of the Wheatstone bridge to obtain... The control module calculates ΔV = 0.61V, determines it falls within the "0.1V < ΔV ≤ 1V" range, sets a matching step size S = 0.06V, and controls the DAC to output a 0.06V positive voltage; the voltage is then acquired again. ΔV = 0.05V (belonging to the range "0.01V < ΔV ≤ 0.1V"), matching step size S = 0.006V; after 3 more iterations, the value is collected. When ΔV = 0.00008V ≤ 0.0001V, the control module triggers the "zeroing complete" signal and stops the loop.

[0032] Through a closed-loop cycle of "acquisition-judgment-adjustment", the zeroing accuracy is ≤0.0001V, which is 100 times higher than the ±0.01V accuracy of traditional manual zeroing. This can meet the stringent accuracy requirements of scenarios such as material testing machines and high-precision electronic scales. At the same time, the closed-loop logic automatically terminates the zeroing, eliminating the need for manual monitoring and reducing human intervention.

[0033] Step 6: Zeroing parameter storage. The control module stores the final adjustment voltage V_final of the DAC module after zeroing is completed into the storage module.

[0034] After zeroing is complete, the control module reads the final output voltage V_final of the DAC module (0.6666V), writes V_final to a specified address (0x00-0x03) in the non-volatile memory module (model: AT24C02, capacity 2KB) via I2C communication, and marks it as "parameter valid". When the sensor restarts after a power outage, the control module reads V_final from this address upon power-up and sends it directly to the DAC module for loading, without needing to repeat steps 1-5.

[0035] In addition, such as Figure 2 The diagram illustrates the hardware signal interaction and step size control correspondence of a force sensor zeroing system. This diagram integrates the "hardware signal flow" and "software step size rules," serving as a visual representation of Embodiments 1 and 2. The initial state is labeled "Setting 0" (DAC initial output 0V, corresponding to the software logic "Setting from 0V" in Document 2); the ADC sampling determination lists the intervals "ADC>1V", "ADC>0.1V", "ADC>0.01V", "ADC>0.001V", and "ADC>0.0001V" (perfectly matching the preset difference interval of Embodiment 1); the DAC step size output is labeled with the intervals "DAC+0.6V", "DAC+0.06V", "DAC+0.006V", "DAC+0.0006V", and "DAC+0.00006V" (i.e., the adaptive step size S of Embodiment 1). Furthermore, the implicit stable sampling value labels such as "AD01V" and "ADC1V" correspond to the processing effect of "ADC built-in low-pass filter (cutoff frequency 10Hz)" in Example 2 (after filtering out power frequency noise, the sampling fluctuation is reduced from ±0.05V to ±0.001V). This also reflects the "voltage direction control" in Example 2 (such as...). (When the DAC outputs a reverse voltage). In summary, this figure corresponds to "In Example 1" The adjustment process of "".

[0036] It solves the problem of traditional manual zeroing requiring readjustment every time power is turned on, reducing the time for zeroing after power-on from 2 minutes to less than 10 seconds, greatly improving the efficiency of equipment start-up and shutdown; at the same time, non-volatile storage can save parameters for a long time, and they will not be lost even if power is off, avoiding the cumulative error in accuracy caused by repeated zeroing.

[0037] Example 2 Optionally, in step 1), the ADC module acquires... Previously, the method also included: The output voltage of the force sensor Wheatstone bridge is low-pass filtered to remove power frequency noise and high-frequency interference signals.

[0038] In the ADC module (ADS1115), its built-in low-pass filter unit is enabled, and the filter cutoff frequency is configured to 10Hz. However, there is 50Hz power frequency interference from workshop motors at the sensor installation site. Without filtering enabled, the ADC acquisition... The fluctuation range is 1.23V ± 0.05V. After enabling filtering, The fluctuation range was reduced to 1.23V±0.001V, and the fluctuation amplitude was reduced by 98%.

[0039] Effectively filters out on-site power frequency noise and high-frequency electromagnetic interference, preventing noise from distorting the ADC sampling values. Without filtering, fluctuations... This may cause the control module to misjudge the ΔV range (e.g., 1.23V + 0.05V = 1.28V is still considered "ΔV > 1V", but 1.23V - 0.05V = 1.18V may be misjudged as "0.1V < ΔV ≤ 1V"), resulting in incorrect step size selection; after filtering, the sampled value is stable, ensuring the accuracy of the range determination and step size matching, and indirectly improving the zeroing accuracy.

[0040] Optionally, in step 4, the voltage direction of V_adjust is determined according to... The relationship between the value of V_target and the value of V_target is determined by methods including: like If so, the DAC module outputs a positive V_adjust; like If so, the DAC module outputs the inverted V_adjust.

[0041] When the force sensor causes the Wheatstone bridge to output a negative voltage due to installation stress (such as...) In step 4, the control module determines that " The system sends a "reverse output" command to the DAC module, matching the range of "0.1V < ΔV ≤ 1V" where ΔV = 0.32V, with a step size S = 0.06V. The DAC module outputs -0.06V (reverse adjustment voltage); data is then acquired after loading. Continue to output 0.06V in reverse until ΔV=0.00009V.

[0042] Covering both "forward zero drift" and "reverse zero drift" scenarios, this solution addresses the problem of "limited potentiometer adjustment range in traditional manual zero adjustment, which cannot compensate for reverse zero drift." Traditional potentiometers, if their initial resistance is already at its minimum, cannot further reduce the resistance to compensate for reverse zero drift. However, this solution, through bidirectional voltage adjustment, can adapt to all zero drift directions, improving the versatility of zero adjustment.

[0043] Optionally, in step 6, the storage module is a non-volatile memory. When the force sensor is powered on and started up again, the control module directly calls V_final stored in the storage module to perform initial compensation on the Wheatstone bridge without having to repeat the zeroing process.

[0044] The storage module uses an EEPROM (AT24C02), which retains data for more than 10 years after power failure. The force sensors on a certain production line need to be powered off for maintenance every day. Without this solution, manual zeroing is required after each maintenance, which takes 20 minutes per unit. With this solution, after a power failure and restart, the control module automatically reads V_final=0.6666V stored in the EEPROM and sends it directly to the DAC module for loading. Initial compensation is completed within 10 seconds without manual operation.

[0045] It enables long-term storage and rapid reuse of zeroing parameters, solving the efficiency problem of traditional manual zeroing that requires readjustment after each power outage. It is especially suitable for industrial scenarios that require frequent start-stop and maintenance. A single sensor can save more than 100 hours of zeroing time per year, reducing labor costs.

[0046] Example 3 In addition to the above embodiments, temperature drift compensation is also included.

[0047] The operating ambient temperature T of the force sensor is collected in real time through the temperature detection module; When the deviation of T from the reference temperature (25℃) is ΔT > ±5℃, the control module adjusts S according to the preset temperature-step correction coefficient. The temperature-step correction coefficient is ±0.00001V for every 1℃ deviation of T from the reference temperature.

[0048] In one possible implementation, a temperature detection module (model: DS18B20, temperature range -55℃~125℃, accuracy ±0.5℃) is added, and its output is connected to the control module's I2C interface. The preset reference temperature is 25℃, and the temperature-step correction coefficient is "for every 1℃ deviation from the reference temperature, the step size is corrected by ±0.00001V". When the ambient temperature rises to 35℃, the temperature detection module acquires T=35℃, calculates ΔT=35℃-25℃=10℃, and the control module corrects the step size S to "base step size + 10×0.00001V". For example, if the base step size is 0.0006V (ΔV=0.0006V), the corrected step size is 0.0007V. Without compensation, a 10℃ temperature increase causes a bridge zero drift of 0.002V, and after compensation, the zero drift is controlled within 0.0001V.

[0049] To counteract the effects of ambient temperature changes on the Wheatstone bridge, traditional manual zeroing lacks temperature compensation. When the temperature fluctuates, the bridge resistance changes with the temperature (e.g., the temperature coefficient of the strain gauge causes resistance drift), and zero drift reappears shortly after zeroing, requiring frequent readjustment. This solution uses dynamic temperature-step correction to keep the zeroing accuracy stable within the range of -10℃ to 50℃, reducing the frequency of readjustment and improving the long-term reliability of the equipment.

[0050] Example 4 On the other hand, a force sensor field zeroing system for implementing the above method is provided, including an ADC sampling module, a DAC output module, a control module and a storage module; The input terminal of the ADC sampling module is electrically connected to the output terminal of the Wheatstone bridge of the force sensor, and the output terminal is electrically connected to the first input terminal of the control module. It is used to collect the output voltage of the Wheatstone bridge and transmit it to the control module. The input terminal of the DAC output module is electrically connected to the first output terminal of the control module, and the output terminal is electrically connected to the compensation terminal of the Wheatstone bridge. It is used to receive commands from the control module and output an adjusted voltage. The storage module is electrically connected to the second output terminal of the control module and is used to store the final adjustment voltage V_final of the DAC output module; the control module is used to perform difference calculation, step size matching and cyclic zeroing logic.

[0051] In one possible implementation, a zeroing system is constructed. The input terminal of the ADC sampling module (ADS1115) is connected to the output terminal of the Wheatstone bridge of the force sensor, and the output terminal is connected to the control module (STM32F103) via I2C; the input terminal of the DAC output module (DAC8552) is connected to the SPI interface of the control module, and the output terminal is connected to the bridge compensation terminal via a current-limiting resistor; the storage module (AT24C02) is connected to the control module via I2C; after the system is powered on, the control module automatically executes the zeroing process of claim 1, completing the zeroing within 3 minutes with a zeroing accuracy of 0.00008V; the traditional hardware zeroing system (including knob potentiometer and testing instrument) requires two people to operate, takes 30 minutes, and has an accuracy of only 0.01V.

[0052] Therefore, a complete digital zeroing system can replace the traditional hardware zeroing combination of "potentiometer + testing instrument + manual operation". Traditional systems rely on manual operation, and their accuracy and efficiency are greatly affected by the experience of the personnel. In addition, the equipment is bulky (requiring external testing instruments). This system has a high degree of integration, does not require external instruments, and automatically completes zeroing. Its accuracy and efficiency are stable and controllable, and it is suitable for the compact installation and automation requirements of industrial sites.

[0053] Optionally, a temperature detection module is also included. The output of the temperature detection module is electrically connected to the second input of the control module. It is used to collect the ambient temperature T of the force sensor and transmit it to the control module so that the control module can correct the DAC adjustment step size S.

[0054] The temperature detection module uses the DS18B20, with its probe closely attached to the strain gauge mounting area of ​​the force sensor (ensuring the detected temperature matches the bridge's operating temperature). It communicates with the control module via a single-bus protocol, with a sampling interval of 1 second. When an air conditioning malfunction causes a sudden temperature rise (from 25°C to 38°C within 5 minutes), the temperature detection module captures the temperature change in real time and transmits T=38°C to the control module within 1 second. The control module immediately triggers a step correction (ΔT=13°C, step correction +0.00013V) to prevent the accuracy from exceeding the limit due to a sudden temperature rise.

[0055] Real-time monitoring of the temperature in the core working area of ​​the sensor is achieved, providing accurate data support for temperature compensation. Compared with ambient temperature detection (such as detecting the overall temperature of a workshop), temperature detection close to the strain gauge can reduce "temperature transmission delay" and "temperature difference error", ensuring the timeliness and accuracy of step size correction and further improving the temperature compensation effect.

[0056] Optionally, the sampling accuracy of the ADC sampling module is not less than 16 bits, and the resolution of the DAC output module is not less than 12 bits, in order to meet the requirement of zero-adjustment accuracy ≤ 0.0001V.

[0057] The ADC sampling module uses 16-bit precision (ADS1115, minimum resolution 0.00015258789V), and the DAC output module uses 12-bit resolution (DAC8552, minimum resolution 0.001220703125V). If a 12-bit ADC (minimum resolution 0.000976V) is used, it will be impossible to distinguish between ΔV=0.0005V and ΔV=0.0008V, resulting in step size matching errors. The 16-bit ADC can accurately identify voltage changes at the level of 0.00001V, and the 12-bit DAC can output adjustment voltages at the level of 0.0001V, ultimately achieving a zero-adjustment accuracy of 0.00008V, meeting the requirements of high-precision force measurement scenarios.

[0058] By using a high-precision ADC and a high-resolution DAC, the zero-adjustment accuracy can be ensured to reach 0.0001V. Traditional manual zero-adjustment relies on potentiometers (with a resolution of about 0.01V), which cannot achieve this level of accuracy. The hardware parameters of this solution provide the foundation for high-precision zero-adjustment and solve the problem of "insufficient hardware resolution leading to accuracy bottleneck" in traditional solutions.

[0059] Optionally, the ADC sampling module has a built-in low-pass filter unit with a cutoff frequency of 10Hz, which is used to filter out 50Hz / 60Hz power frequency noise and high-frequency interference signals in the working environment of the force sensor.

[0060] The ADC sampling module (ADS1115) has a built-in RC low-pass filter unit. By configuring the filter resistor R=15.9kΩ and the filter capacitor C=1μF through the configuration register, the cutoff frequency f=1 / (2πRC)=10Hz is calculated. There is high-frequency welding equipment in the field (generating interference signals above 1kHz). When the built-in filter is not enabled, the ADC sampling value shows a high-frequency fluctuation of 0.02V, which leads to the ΔV calculation error. After enabling the built-in filter, the high-frequency interference is suppressed, the sampling value fluctuation is reduced to within 0.0005V, and the ΔV calculation error is <0.0001V.

[0061] No additional external filter circuit is required, simplifying the system hardware structure (avoiding the space occupied by external filter boards). At the same time, it effectively suppresses high-frequency interference. Traditional solutions require additional RC filter circuits if filtering is needed, increasing hardware costs and assembly complexity. The integrated filter design of this solution improves system integration and reliability while ensuring anti-interference effect and reducing hardware costs.

[0062] Combining Examples 3 and 4, such as Figure 3 The diagram shows a complete system structure for field zeroing of a force sensor with temperature compensation. This diagram is a visual representation of the "Complete Zeroing System" in Embodiment 4, and also integrates the "Temperature Compensation" logic from Embodiment 3.

[0063] The core modules include an ADC sampling module (with built-in low-pass filter), a DAC output module, a control module, a storage module (non-volatile memory, such as AT24C02), and a temperature detection module (such as DS18B20).

[0064] The connection relationships are as follows: ADC input terminal → Wheatstone bridge output terminal of force sensor; DAC output terminal → Wheatstone bridge compensation terminal (connected with a 1kΩ current-limiting resistor); temperature detection module → closely attached to the strain gauge of force sensor (to ensure accurate temperature acquisition), output terminal → second input terminal of control module; storage module → bidirectional communication with control module (to realize V_final storage and power-on multiplexing). The temperature compensation logic is marked with a path of "temperature acquisition → ΔT determination → step size correction", corresponding to the scenario of "T=35℃ → ΔT=10℃ → step size +0.0001V". Furthermore, the system functionality also reflects the parameter reuse logic of "automatically calling V_final upon power-on" (eliminating the need for repeated zeroing).

[0065] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0066] Those skilled in the art will understand that all or part of the steps of the above embodiments can be implemented by hardware, or by a program instructing related hardware. The program can be stored in a computer-readable storage medium, such as a read-only memory, a disk, or an optical disk. The above descriptions are merely optional embodiments of this application and are not intended to limit the application. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for zeroing a force sensor in the field, characterized in that, The method includes: Step 1) Initial signal acquisition: Acquire the initial output voltage value of the force sensor's Wheatstone bridge using an analog-to-digital converter (ADC) module. and the Transmitted to the control module; Step 2) Difference calculation and interval determination: The control module will... The difference is calculated by performing a difference operation between the value and the target zero value V_target (where V_target is 0V ± 0.0001V). The system determines the preset difference range to which ΔV belongs, and the preset difference range includes ΔV > 1V, 0.1V < ΔV ≤ 1V, 0.01V < ΔV ≤ 0.1V, 0.001V < ΔV ≤ 0.01V, and 0.0001V < ΔV ≤ 0.001V. Step 3) Adaptive step size matching: The control module matches the corresponding digital-to-analog converter (DAC) and adjusts the step size S according to the preset difference range to which ΔV belongs: if ΔV > 1V, then S = 0.6V; if 0.1V < ΔV ≤ 1V, then S = 0.06V; if 0.01V < ΔV ≤ 0.1V, then S = 0.006V; if 0.001V < ΔV ≤ 0.01V, then S = 0.0006V; if 0.0001V < ΔV ≤ 0.001V, then S = 0.00006V. Step 4) Compensation voltage output: The control module sends a control command to the DAC module, causing the DAC module to output an adjustment voltage V_adjust corresponding to S, and loads V_adjust to the compensation terminal of the Wheatstone bridge to adjust the balance state of the Wheatstone bridge. Step 5) Accuracy verification and cyclic zeroing: Repeat steps 1) to 4), continuously collect the adjusted force sensor output voltage and calculate ΔV until ΔV ≤ 0.0001V, at which point the control module determines that the zeroing is complete; Step 6) Zeroing parameter storage: The control module stores the final adjustment voltage V_final of the DAC module after zeroing is completed into the storage module.

2. The field zeroing method for a force sensor according to claim 1, characterized in that, In step 1), the ADC module acquires the data. The method further includes: The output voltage of the force sensor Wheatstone bridge is subjected to low-pass filtering to remove power frequency noise and high-frequency interference signals.

3. The on-site zeroing method for a force sensor according to claim 1, characterized in that, In step 4), the voltage direction of V_adjust is determined based on the relationship between the magnitudes of V0 and V_target. The determination method includes: like If so, the DAC module outputs a positive V_adjust; like Then the DAC module outputs an inverted V_adjust.

4. The field zeroing method for a force sensor according to claim 1, characterized in that, The method further includes: The operating ambient temperature T of the force sensor is collected in real time through the temperature detection module; When the deviation ΔT between T and the reference temperature (25℃) is greater than ±5℃, the control module adjusts S according to the preset temperature-step correction coefficient. The temperature-step correction coefficient is such that for every 1℃ deviation of T from the reference temperature, S is corrected by ±0.00001V.

5. The field zeroing method for a force sensor according to claim 1, characterized in that, In step 6), the storage module is a non-volatile memory. When the force sensor is powered on and started again, the control module directly calls V_final stored in the storage module to perform initial compensation on the Wheatstone bridge without repeating the zeroing process.

6. A force sensor field zeroing system, characterized in that, The field zeroing method for a force sensor as described in any one of claims 1 to 5, wherein the system includes an ADC sampling module, a DAC output module, a control module, and a storage module; The input terminal of the ADC sampling module is electrically connected to the output terminal of the Wheatstone bridge of the force sensor, and the output terminal is electrically connected to the first input terminal of the control module, for acquiring the output voltage of the Wheatstone bridge and transmitting it to the control module; The input terminal of the DAC output module is electrically connected to the first output terminal of the control module, and the output terminal is electrically connected to the compensation terminal of the Wheatstone bridge, for receiving instructions from the control module and outputting an adjustment voltage; The storage module is electrically connected to the second output terminal of the control module and is used to store the final adjustment voltage V_final of the DAC output module; the control module is used to perform difference calculation, step size matching and cyclic zeroing logic.

7. The force sensor field zeroing system according to claim 6, characterized in that, It also includes a temperature detection module, the output of which is electrically connected to the second input of the control module, for collecting the ambient temperature T of the force sensor and transmitting it to the control module, so that the control module can correct the DAC adjustment step size S.

8. The force sensor field zeroing system according to claim 6, characterized in that, The sampling accuracy of the ADC sampling module is not less than 16 bits, and the resolution of the DAC output module is not less than 12 bits, in order to meet the requirement of zero-adjustment accuracy ≤ 0.0001V.

9. The force sensor field zeroing system according to claim 6, characterized in that, The ADC sampling module has a built-in low-pass filter unit with a cutoff frequency of 10Hz, which is used to filter out 50Hz / 60Hz power frequency noise and high-frequency interference signals in the working environment of the force sensor.

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