A human body scale four-corner deviation testing machine and a loading force value calibration and application method thereof

Abstract

This invention relates to a body scale four-corner deviation testing machine, comprising a frame, on which a weight loading device is provided. The weight loading device includes a mounting frame and a weight. A lever is rotatably connected to the mounting frame, and the lever is connected to the weight to drive the weight to move up and down. The weight loading device also includes a driving device. A first spring is provided between the upper part of the weight and the mounting frame, and a second spring is provided between the lower part of the weight and the mounting frame. The first and second springs extend horizontally. The mounting frame, the first spring, the weight, and the second spring are sequentially fixedly connected to form a quadrilateral guide mechanism to constrain the movement trajectory of the weight, so that the landing position of the weight can remain consistent each time it descends to the preset loading height. This invention also provides a method for calibrating and applying the loading force value of the body scale four-corner deviation testing machine, by establishing a mapping relationship between the monitoring sensor and the standard force value at the actual loading position, thereby compensating for mechanical installation deviations.

Description

Technical Field

[0001] This invention relates to the field of body scale testing technology, specifically to a body scale four-corner deviation testing machine and its loading force value calibration and application method. Background Technology

[0002] The measurement accuracy of a body scale directly affects user experience and product quality. To ensure the accuracy of body scales before they leave the factory, each body scale undergoes an angle difference test on the production line. This test involves applying a standard load to different areas of the scale surface to detect the consistency error between the readings at various locations and the standard values, thereby determining whether the measurement results are consistent when weighing at different locations.

[0003] Existing body scale corner deviation testing machines typically use multi-axis motion modules or pneumatic mechanisms to drive standard weights onto the testing areas of the scale surface. The displayed values ​​are then read and compared with standard values ​​to calculate the corner difference. The applicant previously applied for a utility model patent in China (Patent Publication No. CN223769629U) entitled "An Automatic Testing Machine for the Four-Corner Measurement Deviation of a Body Scale," which uses a cylinder to achieve vertical loading of the weights. However, these components inevitably develop minute mechanical gaps, wear, or uneven lubrication during long-term reciprocating motion. After multiple loading cycles, the fit between the cylinder push rod and the guide rail may change, causing slight tilting and offset of the weight's posture and the contact position between the weight and the weight's bearing weight. This positional repeatability error introduces additional torque, affecting the consistency and accuracy of the test results. Furthermore, the standard weights on this body scale corner deviation testing machine generally need to be periodically disassembled and sent to a higher-level standard machine for individual calibration. However, the disassembly, inspection, and reassembly procedures are cumbersome, resulting in long equipment downtime and impacting production efficiency. After the weights are reinstalled, the mechanical coupling state, such as the flatness of the contact surface between the weights and the loading mechanism and the tightening torque, may change slightly, causing the calibrated standard value to drift again during actual loading, introducing secondary errors. Summary of the Invention

[0004] The purpose of this invention is to provide a body scale four-corner deviation testing machine. By using a quadrilateral guide mechanism composed of a first spring, a second spring, a weight, and an installation frame, the movement trajectory of the weight is constrained, so that the landing position of the weight can remain consistent each time it falls to a preset loading height. This solves the problem that position repeatability error will introduce additional torque and affect the consistency and accuracy of the test results.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a body scale four-corner deviation testing machine, including a frame, on which are provided four sets of weight loading devices for loading weights onto the body scale. The four sets of weight loading devices are respectively set to the four bearing points of the body scale. Each weight loading device includes a mounting frame and weights. A lever is rotatably connected to the mounting frame. The lever is connected to the weights to drive the weights to move up and down. The weight loading device also includes a driving device capable of driving the levers to rotate. A first spring is provided between the upper part of the weight and the mounting frame, and a second spring is provided between the lower part of the weight and the mounting frame. The first spring and the second spring extend horizontally. The mounting frame, the first spring, the weights, and the second spring are sequentially fixedly connected to form a quadrilateral guide mechanism.

[0006] As a further optimization of the present invention, the first spring has a first free section located between the weight and the mounting frame, and the second spring has a second free section located between the weight and the mounting frame. When the weight is lowered to a preset loading height, the first free section and the second free section are arranged parallel to the horizontal direction.

[0007] As a further optimization of the present invention, the length L1 of the first free segment is equal to the length L2 of the second free segment.

[0008] As a further optimization of the present invention, the first free segment is provided with two first clamping plates, which are respectively fitted to the upper and lower surfaces of the first spring sheet to clamp and fix the middle part of the first free segment from opposite directions. A first bending gap is left between the two ends of the first clamping plates in the length direction and the two ends of the first free segment for the first spring sheet to bend. The second free segment is provided with two second clamping plates, which are respectively fitted to the upper and lower surfaces of the second spring sheet to clamp and fix the middle part of the second free segment from opposite directions. A second bending gap is left between the two ends of the second clamping plates in the length direction and the two ends of the second free segment for the second spring sheet to bend.

[0009] As a further optimization of the present invention, the width of each of the two first clamping plates is not less than the width of the first spring sheet, so as to cover the first spring sheet in the width direction; the width of each of the two second clamping plates is not less than the width of the second spring sheet, so as to cover the second spring sheet in the width direction.

[0010] As a further optimization of the present invention, the mounting frame includes an upper mounting plate and a lower mounting plate arranged at intervals along the vertical direction. Both the upper and lower mounting plates extend horizontally. A first pressure block is provided above the top surface of the upper mounting plate. One end of the first spring piece is placed on the top surface of the upper mounting plate and clamped and fixed between the first pressure block and the upper mounting plate. A second pressure block is provided above the top surface of the weight. The other end of the first spring piece is placed on the top surface of the weight and clamped and fixed between the second pressure block and the weight. A third pressure block is provided below the bottom surface of the lower mounting plate. One end of the second spring piece is placed on the bottom surface of the lower mounting plate and clamped and fixed between the third pressure block and the lower mounting plate. A fourth pressure block is provided below the bottom surface of the weight. The other end of the second spring piece is placed on the bottom surface of the weight and clamped and fixed between the fourth pressure block and the weight.

[0011] As a further optimization of the present invention, each set of weight loading devices is equipped with a monitoring sensor for collecting the force value signal when the corresponding weight is loaded.

[0012] The present invention also aims to provide a method for calibrating and applying loading force values, which compensates for mechanical installation deviations by establishing a mapping relationship between monitoring sensors and standard force values ​​at actual loading positions.

[0013] To solve the above-mentioned technical problems, the present invention also provides the following technical solution: a method for calibrating and applying the loading force value of a body scale four-corner deviation testing machine, wherein the device for implementing the method includes a calibration sensor detachably placed on the loading station of the four-corner deviation testing machine, and the method includes the following steps:

[0014] S1. Place the calibration sensor on the loading station of the four-corner deviation tester, and drive the weights of the four sets of weight loading devices to apply load to the calibration sensor in sequence. Simultaneously collect the output values ​​of the calibration sensor and the monitoring sensor when each set of weight loading devices applies load, establish the mapping relationship between the output value of the monitoring sensor and the output value of the calibration sensor, and store the mapping relationship as calibration parameters.

[0015] S2. When performing the body scale angle difference test, read the output value of the monitoring sensor of each set of weight loading device, convert the output value of the monitoring sensor into the actual loading force value according to the pre-stored mapping relationship, and correct the body scale angle difference data based on the actual loading force value.

[0016] As a further optimization of the present invention, step S1 includes the following steps:

[0017] S11. Place the calibrated sensor with traceable measurement values ​​at the loading station of the body scale four-corner deviation testing machine. The calibrated sensor has a pre-stored standard force value. ;

[0018] S12. The four sets of weight loading devices are driven sequentially to apply a load to the calibration sensor. After each set of weights is loaded, the output value of the calibration sensor under that loading is collected synchronously. and the corresponding output values ​​of the monitoring sensors The =1~4, used to identify the four sets of weight loading devices respectively;

[0019] S13. Calculate the actual loading coefficient of each weight based on the collected data. = And calculate the actual effective weight of each weight based on the loading coefficient. = ,in This refers to the nominal weight of the corresponding weight;

[0020] S14. Based on the actual effective weight of each weight and the corresponding output values ​​of the monitoring sensors. Calculate the calibration coefficient for each loaded monitoring sensor. = Each calibration coefficient This serves as the calibration parameter for the loading force value of the corresponding weight loading device.

[0021] As a further optimization of the present invention, step S2 includes the following steps:

[0022] S21. Sequentially drive the four sets of weight loading devices to apply a load to the body scale, and collect the output value of the monitoring sensor of each set of weight loading devices when the load is applied. Then, the calibration coefficients pre-stored in the corresponding weight loading device are called. The actual loading force of the weight loading device was calculated. = × ;

[0023] S22, based on the actual loading force at the four load-bearing points Based on this, the output value of the body scale is normalized to correct the angle difference of the body scale.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] 1. A quadrilateral guide mechanism consisting of a first spring, a second spring, a weight, and an mounting frame is used to constrain the movement trajectory of the weight. Compared with the tilting of the weight caused by guide rail wear and gaps in traditional mechanical structure loading, this structure can ensure that the posture and landing position of the weight are consistent each time it is loaded, reducing random errors caused by mechanical positioning problems. This avoids introducing additional torque to the weight bearing weight of the human body scale due to the tilting or eccentric loading of the weight, and improves the accuracy and reliability of the angle difference test data.

[0026] 2. By employing in-situ calibration, a mapping relationship between the monitoring sensor and the standard force value is established at the actual loading position, and the weights, loading mechanism, and installation status are systematically calibrated as a whole. This compensates for mechanical installation deviations and ensures the accuracy and reliability of the loading force value. Attached Figure Description

[0027] Figure 1 This is a three-dimensional schematic diagram of the present invention;

[0028] Figure 2 This is a three-dimensional schematic diagram of the weight loading device in this invention;

[0029] Figure 3 This is an exploded view of the weight loading device in this invention. Figure 1 ;

[0030] Figure 4 This is an exploded view of the weight loading device in this invention. Figure 2 ;

[0031] Figure 5 This is an exploded view of the weight loading device in this invention. Figure 3 ;

[0032] Figure 6 This is a cross-sectional schematic diagram of the weight loading device in this invention;

[0033] Figure 7 This is a schematic diagram of the operation of the weight loading device in this invention;

[0034] Figure 8 This is a flowchart illustrating the method for calibrating and applying the applied force value in this invention. Detailed Implementation

[0035] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0036] like Figures 1 to 8As shown, this invention discloses a body scale four-corner deviation testing machine, including a frame 1. The frame 1 is equipped with four sets of weight loading devices 2 for loading weights onto the body scale. The four sets of weight loading devices 2 are respectively set for the four bearing points of the body scale. Each weight loading device 2 includes a mounting frame 3 and a weight 4. A lever 5 is rotatably connected to the mounting frame 3. The lever 5 is connected to the weight 4 to drive the weight 4 to move up and down. The weight loading device 2 also includes a driving device 7 that can drive the lever 5 to rotate. A first spring 81 is provided between the upper part of the weight 4 and the mounting frame 3, and a second spring 82 is provided between the lower part of the weight 4 and the mounting frame 3. The first spring 81 and the second spring 82 extend horizontally. The mounting frame 3, the first spring 81, the weight 4, and the second spring 82 are sequentially fixedly connected to form a quadrilateral guide mechanism.

[0037] like Figures 1 to 7 As shown, in this embodiment, the frame 1 provides a stable support platform. There are four sets of weight loading devices 2, each corresponding to a weight-bearing point at one of the four corners of the scale. The mounting frame 3 is fixed to the frame. The middle of the lever 5 is hinged to the mounting frame 3, and one end of the lever 5 is connected to the weight 4 via a drive structure 6. The drive structure 6 converts the swing of the lever 5 into a pushing or pulling force on the weight 4, allowing the lever 5 to be driven by the drive device 7, thus moving the weight 4 up and down. The weight 4 is used as a standard load for angle difference detection. In this embodiment, the weight 4 is a vertically oriented rectangular block. The drive device 7 is a cylinder mounted on the mounting frame and corresponding to the other end of the lever 5. The extension and retraction of the cylinder's telescopic rod pushes the lever 5 to rotate around the hinge point. The drive device 7 can also drive the lever 5 using a servo motor or similar means. The first spring plate 81 and the second spring plate 82 can be made of materials with high axial stiffness and low bending stiffness, such as spring steel. Both the first spring plate 81 and the second spring plate 82 extend horizontally and are arranged vertically in parallel at intervals, forming two sets of symmetrical connection structures. The mounting frame 3, the first spring plate 81, the weight 4, and the second spring plate 82 are sequentially fixedly connected to form a quadrilateral guide mechanism to guide the movement of the weight 4. Compared to the tilting of the weight caused by guide rail wear and gaps in traditional mechanical loading structures, the first spring plate 81 and the second spring plate 82 can respectively limit the upper and lower parts of the weight 4 during its movement, ensuring that the weight 4 does not rotate around the horizontal axis or deflect around the vertical axis. This ensures that the landing point of the weight 4 coincides each time it descends to the loading height, eliminating the error in the human body scale angle difference detection system caused by loading landing point deviation.

[0038] The quadrilateral guide mechanism, consisting of the first spring 81, the second spring 82, the weight 4, and the mounting bracket 3, constrains the movement trajectory of the weight 4. Compared to the tilting of the weight caused by guide rail wear and gaps in traditional mechanical loading, this structure can ensure that the posture and landing position of the weight 4 are consistent each time it is loaded, reducing random errors caused by mechanical positioning problems. This avoids introducing additional torque to the weight bearing weight of the human body scale due to the tilting or eccentric loading of the weight 4, and improves the accuracy and reliability of the angle difference test data.

[0039] The first spring 81 has a first free section 811 located between the weight 4 and the mounting bracket 3, and the second spring 82 has a second free section 821 located between the weight 4 and the mounting bracket 3. When the weight 4 descends to the preset loading height, the first free section 811 and the second free section 821 are arranged parallel to the horizontal direction.

[0040] When lever 5 rotates and drives weight 4 downward to the preset loading height, the first free segment 811 and the second free segment 821 are in a near-horizontal natural state. At this time, the first spring 81 and the second spring 82 mainly bear a small constraint force in the horizontal direction, while generating almost no component force in the vertical direction. The weight of weight 4 acts almost entirely vertically on the sensor being measured on the body scale, ensuring the accuracy and consistency of the loading force value and improving the accuracy of the detection data.

[0041] The length L1 of the first free segment 811 is equal to the length L2 of the second free segment 821.

[0042] In this embodiment, the first spring 81 and the second spring 82 are made of the same material and have the same specifications. When the length L1 of the first free segment 811 is equal to the length L2 of the second free segment 821 and the lever 5 drives the weight 4 to move up and down, the first spring 81 and the second spring 82 can undergo symmetrical bending deformation of equal amplitude, thereby constraining the weight 4 to limit the tilting of the weight 3.

[0043] The first free segment 811 is provided with two first clamping plates 91, which are respectively attached to the upper and lower surfaces of the first spring sheet 81 to clamp and fix the middle part of the first free segment 811. A first bending gap 92 is left between the two ends of the first clamping plate 91 in the length direction and the two ends of the first free segment 811 for the first spring sheet 81 to bend. The second free segment 821 is provided with two second clamping plates 93, which are respectively attached to the upper and lower surfaces of the second spring sheet 82 to clamp and fix the middle part of the second free segment 821. A second bending gap 94 is left between the two ends of the second clamping plate 93 in the length direction and the two ends of the second free segment 821 for the second spring sheet 82 to bend.

[0044] In this embodiment, two rigid first clamping plates 91 are provided on the first free segment 811. The two first clamping plates 91 are respectively disposed on the upper and lower sides of the first spring piece 81, and are locked and fixed to the first spring piece 81 through locking bolts arranged along the length or width direction of the spring piece, forming a rigid clamping of the middle part of the first free segment 811. This restricts the section of the first spring piece 81 covered by the two first clamping plates 91 from elastically bending and deforming. A first bending gap 92 is left between the two ends of the first clamping plates 91 in the length direction and the two ends of the first free segment 811 for the first spring piece 81 to bend, thereby limiting the deformation area of ​​the first spring piece 81 to within the first bending gap 92 between the two ends of the first clamping plates 91 in the length direction and the two ends of the first free segment 811, realizing precise control of the effective deformation length of the first spring piece 81. Similarly, the second free segment 821 is provided with two rigid second clamping plates 93, which are respectively located on the upper and lower sides of the second spring piece 82. The two second clamping plates 93 are locked and fixed to the second spring piece 82 through locking bolts arranged along the length or width direction of the spring piece, forming a rigid clamping of the middle part of the second free segment 821. This completely restricts the section of the second spring piece 82 covered by the two second clamping plates 93, preventing elastic bending deformation. A second bending gap 94 is left between the two ends of the second clamping plates 93 in the length direction and the two ends of the second free segment 821 to allow the second spring piece 82 to bend. This limits the deformation area of ​​the second spring piece 82 to the second bending gap 94 between the two ends of the second clamping plates 93 in the length direction and the two ends of the second free segment 821, thereby achieving precise control of the effective deformation length of the second spring piece 82. In the embodiment, the lengths of the first bending gap 92 and the second bending gap 94 are between 3 mm and 8 mm. By setting the first bending gap 92 on both sides of the first spring sheet 81 and the second bending gap 94 on both sides of the second spring sheet 82, the bending stress can be distributed in two deformation sections, reducing stress concentration and improving service life.

[0045] The width of each of the two first clamping plates 91 is not less than the width of the first spring piece 81, so as to cover the first spring piece 81 in the width direction; the width of each of the two second clamping plates 93 is not less than the width of the second spring piece 82, so as to cover the second spring piece 82 in the width direction.

[0046] In this embodiment, the width of each of the two first clamping plates 91 is not less than the width of the first spring piece 81. This ensures that the first clamping plates 91 completely cover the edge of the first spring piece 81 in the width direction. This limits the possibility of the first spring piece 81 twisting or partially warping along its length direction when subjected to force. Similarly, the second clamping plate 93 also completely covers the width of the second spring piece 82, thereby improving the reliability of clamping.

[0047] The mounting bracket 3 includes an upper mounting plate 31 and a lower mounting plate 32 arranged vertically at intervals. Both the upper mounting plate 31 and the lower mounting plate 32 extend horizontally. A first pressure block 33 is provided above the top surface of the upper mounting plate 31. One end of the first spring piece 81 is placed on the top surface of the upper mounting plate 31 and clamped and fixed between the first pressure block 33 and the upper mounting plate 31. A second pressure block 95 is provided above the top surface of the weight 4. The other end of the first spring piece 81 is placed on the top surface of the weight 4 and clamped and fixed between the second pressure block 95 and the weight 4. A third pressure block 34 is provided below the bottom surface of the lower mounting plate 32. One end of the second spring piece 82 is placed on the bottom surface of the lower mounting plate 32 and clamped and fixed between the third pressure block 34 and the lower mounting plate 32. A fourth pressure block 96 is provided below the bottom surface of the weight 4. The other end of the second spring piece 82 is placed on the bottom surface of the weight 4 and clamped and fixed between the fourth pressure block 96 and the weight 4.

[0048] In this embodiment, the left end of the first spring piece 81 is locked and clamped to the upper mounting plate 31 by the first pressure block 33, forming a first clamping and fixing section. The right end of the first spring piece 81 is locked and clamped to the top surface of the weight 4 by the second pressure block 95, forming a second clamping and fixing section. The first free section 811 is the section between the inner edge of the first clamping and fixing section and the inner edge of the second clamping and fixing section, and the length L1 of the first free section 811 is the horizontal straight-line distance between the inner edges of the two clamping and fixing sections. The left end of the second spring piece 82 is locked and clamped to the lower mounting plate 32 by the third pressure block 34, forming a third clamping and fixing section. The right end of the second spring piece 82 is locked and clamped to the bottom surface of the weight 4 by the fourth pressure block 96, forming a fourth clamping and fixing section. The second free segment 821 is the section between the inner edge of the third clamping and fixing segment and the inner edge of the fourth clamping and fixing segment. The second free segment 821 is vertically aligned with the first free segment 811, and the length L2 of the second free segment 821 is the horizontal straight-line distance between the inner edges of the third and fourth clamping and fixing segments. The end of the spring sheet directly contacts the plate surface, providing large-area support and reducing stress concentration. Simultaneously, the pressure block design facilitates installation and disassembly, and also allows for adjustment of the spring sheet's preload during assembly.

[0049] like Figure 6As shown in the embodiment, the driving structure 6 includes a receiving groove 61 on the weight 4, one end of the lever 5 extends into the receiving groove 61, and a fitting gap 62 is left between the end of the lever 5 and the upper wall of the receiving groove. By opening the receiving groove 61 on the weight 4 and extending one end of the lever 5 into the groove, a non-rigid connection structure is formed by utilizing the pre-reserved fitting gap 62 between the end of the lever and the upper wall of the receiving groove. This allows the lever 5 to abut against the upper wall of the groove to lift the weight 4 when it swings upward, thereby realizing the function of driving the weight 4 to move in the vertical direction.

[0050] In this embodiment, the lever 5 is also provided with a balance block 51 to adjust the auxiliary counterweight of the lever arm.

[0051] Each set of weight loading devices 2 is equipped with a monitoring sensor 10 for collecting the force value signal when the corresponding weight 4 is loaded.

[0052] Existing testing equipment typically assumes that the applied standard weight load force is constant. However, in actual production environments, due to factors such as air pressure fluctuations, mechanical friction changes, and temperature drift in the drive mechanism, the actual force acting on the weight bearing points of the human body scale is dynamically changing. By setting up the monitoring sensor 10, the four-corner deviation testing machine can avoid directly using the nominal value of the weight when performing four-corner tests. Instead, it can read the actual force value output by the loading monitoring sensor 10 in real time, and eliminate the systematic error introduced by the instability of the loading force source through the differential measurement principle, making the four-corner difference measurement results more accurate and reliable.

[0053] This invention also discloses a method for calibrating and applying a loading force value. The device for implementing this method includes a calibration sensor that can be detachably placed on the loading station of a four-corner deviation testing machine. The method includes the following steps:

[0054] S1. Place the calibration sensor on the loading station of the four-corner deviation tester, and drive the weights 4 of the four sets of weight loading devices 2 to apply load to the calibration sensor in sequence. Simultaneously collect the output values ​​of the calibration sensor and the monitoring sensor 10 when each set of weight loading devices 2 applies load, establish the mapping relationship between the output value of the monitoring sensor 10 and the output value of the calibration sensor, and store the mapping relationship as calibration parameters.

[0055] S2. When performing the body scale angle difference test, read the output value of the monitoring sensor 10 of each set of weight loading device 2, convert the output value of the monitoring sensor 10 into the actual loading force value according to the pre-stored mapping relationship, and correct the body scale angle difference data based on the actual loading force value.

[0056] In one embodiment, when calibrating the loading force value of the four-corner deviation tester, a high-accuracy force sensor and a standard force gauge are detachably placed on the loading station of the four-corner deviation tester. The position of the calibration sensor corresponds to the load-bearing point of the scale under test, and it is used to receive the load applied by the weight 4 and output a standard force value signal. Then, the control system sequentially drives four sets of weight loading devices 2, so that the weight 4 of each set falls individually and applies a load to the calibration sensor. During the loading process of each set of weights, the system synchronously collects the output value of the calibration sensor and the output value of the monitoring sensor 10 provided on the weight loading device 2 of that set, and establishes a mathematical model between the two by data fitting of the collected data, and stores the proportional coefficient, offset, and other data as calibration parameters in the corresponding parameter database in the control system. After calibration is completed, the scale under test is placed on the loading station, and the four-corner deviation test begins. During the test, when a set of weight loading devices drives weight 4 to be loaded onto the body scale, the system reads the current output value of the monitoring sensor 10 in real time, the control system calls the pre-stored mapping relationship of the set, converts the read output value into the current actual loading force value, and compares the actual loading force value with the measurement reading of the body scale in the measurement to complete the correction of the angle difference data.

[0057] By employing in-situ calibration, the complex process of disassembling, sending for inspection, and re-calibrating weights in traditional equipment is simplified to a single, simple placement of the calibration sensor and initiation of an automated process. This not only saves significant time and manpower but also avoids secondary errors caused by repeated disassembly and reassembly, ensuring metrological traceability throughout the equipment's entire lifecycle.

[0058] Step S1 includes the following steps:

[0059] S11. Place the calibrated sensor with traceable measurement values ​​at the loading station of the body scale four-corner deviation testing machine. The calibrated sensor has a pre-stored standard force value. ;

[0060] S12. The four sets of weights 4 of the weight loading device 2 are driven sequentially to apply a load to the calibration sensor. After each set of weights 4 is loaded, the output value of the calibration sensor under that loading is collected synchronously. and the corresponding output value of monitoring sensor 10 The =1~4, respectively used to identify the four sets of weight loading devices 2;

[0061] S13. Calculate the actual loading coefficient of each weight based on the collected data. = And calculate the actual effective weight of each weight 4 according to the loading coefficient. = ,in This corresponds to the nominal weight of weight 4;

[0062] S14, Based on the actual effective weight of each weight 4 and the corresponding output value of the monitoring sensor 10. Calculate the calibration coefficient for each loaded monitoring sensor 10. = Each calibration coefficient This serves as the calibration parameter for the loading force value of the corresponding weight loading device 2.

[0063] In the embodiment, the standard force value This refers to the gravity value or directly calibrated force value generated by the standard mass block corresponding to the calibrated sensor under standard environmental conditions, ensuring the traceability of the measurement results. Through the steps S11 to S14 above, this method uses the calibrated sensor to trace the true value of the nominal weight, and then establishes a linear mapping relationship between the monitoring sensor output and the true value, enabling the equipment to adapt to individual differences of different weights, ensuring that the four-corner deviation tester can provide accurate and consistent loading force values ​​regardless of the environment or after long-term operation.

[0064] Step S2 includes the following steps:

[0065] S21. Sequentially drive the weights 4 of the four sets of weight loading devices 2 to apply a load to the body scale, and collect the output value of the monitoring sensor 10 of each set of weight loading devices 2 when applying the load. Then, the calibration coefficients pre-stored in the corresponding weight loading device 2 are called. The actual loading force of the weight loading device 2 was calculated. = × ;

[0066] S22, based on the actual loading force at the four load-bearing points Based on this, the output value of the body scale is normalized to correct the angle difference of the body scale.

[0067] By acquiring raw signals in real time Multiply by calibration factor This process converts uncalibrated sensor readings into standard force values ​​with metrological traceability. This step eliminates the effects of cylinder friction variations and ambient temperature drift on the applied force, ensuring that the force applied to the scale is known and accurate. The system then applies the actual applied force to the four weight points. Based on this, the output value of the body scale is linearly normalized. The specific algorithm for normalization can be to calculate the actual response sensitivity of the body scale at each point by comparing the output value of the body scale with the actual applied force value, and then calculate the four-corner difference of the body scale based on the normalized data.

[0068] Through steps S21 and S22 described above, this method achieves closed-loop force control and data correction. Because the system always bases its control on the actual applied force value... The calculations ensure that the final measured angle difference data fully reflects the linearity and consistency of the body scale sensor itself, rather than the error of the testing equipment, thus significantly improving the authenticity and reliability of the test results.

Claims

1. A four-corner deviation testing machine for a body scale, comprising a frame (1), four sets of weight loading devices (2) for loading weights on the body scale are arranged on the frame (1), the four sets of weight loading devices (2) are respectively arranged corresponding to four supporting points of the body scale, characterized in that, The weight loading device (2) includes a mounting frame (3) and a weight (4). A lever (5) is rotatably connected to the mounting frame (3). The lever (5) is connected to the weight (4) to drive the weight (4) to move up and down. The weight loading device (2) also includes a driving device (7) that can drive the lever (5) to rotate. A first spring (81) is provided between the upper part of the weight (4) and the mounting frame (3). A second spring (82) is provided between the lower part of the weight (4) and the mounting frame (3). The first spring (81) and the second spring (82) extend in the horizontal direction. The mounting frame (3), the first spring (81), the weight (4), and the second spring (82) are fixedly connected in sequence to form a quadrilateral guide mechanism.

2. The four-corner deviation testing machine for a body scale according to claim 1, wherein The first spring (81) has a first free section (811) located between the weight (4) and the mounting bracket (3), and the second spring (82) has a second free section (821) located between the weight (4) and the mounting bracket (3). When the weight (4) descends to the preset loading height, the first free section (811) and the second free section (821) are arranged parallel to the horizontal direction.

3. The four-corner deviation testing machine for a body scale according to claim 2, characterized by The length L1 of the first free segment (811) is equal to the length L2 of the second free segment (821).

4. The four-corner deviation testing machine for a body scale according to claim 3, wherein The first free segment (811) is provided with two first clamping plates (91), which are respectively attached to the upper and lower surfaces of the first spring sheet (81) to clamp and fix the middle part of the first free segment (811) in opposite directions. A first bending gap (92) is left between the two ends of the first clamping plate (91) in the length direction and the two ends of the first free segment (811) for the first spring sheet (81) to bend. The second free segment (821) is provided with two second clamping plates (93), which are respectively attached to the upper and lower surfaces of the second spring sheet (82) to clamp and fix the middle part of the second free segment (821). A second bending gap (94) is left between the two ends of the second clamping plate (93) in the length direction and the two ends of the second free segment (821) for the second spring sheet (82) to bend.

5. The four-corner deviation testing machine for a body scale according to claim 4, wherein The width of each of the two first clamping plates (91) is not less than the width of the first spring (81) so as to cover the first spring (81) in the width direction; the width of each of the two second clamping plates (93) is not less than the width of the second spring (82) so as to cover the second spring (82) in the width direction.

6. The four-corner deviation testing machine for a body scale according to claim 1, wherein The mounting bracket (3) includes an upper mounting plate (31) and a lower mounting plate (32) arranged vertically at intervals. Both the upper mounting plate (31) and the lower mounting plate (32) extend horizontally. A first pressure block (33) is provided above the top surface of the upper mounting plate (31). One end of the first spring piece (81) is placed on the top surface of the upper mounting plate (31) and clamped and fixed between the first pressure block (33) and the upper mounting plate (31). A second pressure block (95) is provided above the top surface of the weight (4). The other end of the first spring piece (81) is placed on... The second spring (82) is placed on the bottom surface of the weight (4) and clamped and fixed between the second pressure block (95) and the weight (4); a third pressure block (34) is provided below the bottom surface of the lower mounting plate (32), one end of the second spring (82) is placed on the bottom surface of the lower mounting plate (32) and clamped and fixed between the third pressure block (34) and the lower mounting plate (32), a fourth pressure block (96) is provided below the bottom surface of the weight (4), the other end of the second spring (82) is placed on the bottom surface of the weight (4) and clamped and fixed between the fourth pressure block (96) and the weight (4).

7. The four-corner deviation testing machine of any one of claims 1-6, wherein, Each set of weight loading devices (2) is equipped with a monitoring sensor (10) for collecting the force signal when the corresponding weight (4) is loaded.

8. A method for calibrating and applying the loading force value of the four-corner deviation testing machine for a body scale as described in claim 7, characterized in that, The apparatus for implementing this method includes a calibration sensor detachably placed on the loading station of the four-corner deviation testing machine, and the method includes the following steps: S1. Place the calibration sensor on the loading station of the four-corner deviation tester, and drive the weights (4) of the four sets of weight loading devices (2) in sequence to apply load to the calibration sensor. Simultaneously collect the output values ​​of the calibration sensor and the monitoring sensor (10) when each set of weight loading devices (2) applies load, establish the mapping relationship between the output value of the monitoring sensor (10) and the output value of the calibration sensor, and store the mapping relationship as calibration parameters. S2. When performing the body scale angle difference test, read the output value of the monitoring sensor (10) of each set of weight loading device (2), convert the output value of the monitoring sensor (10) into the actual loading force value according to the pre-stored mapping relationship, and correct the body scale angle difference data based on the actual loading force value.

9. The method for calibrating and applying a loading force value according to claim 8, characterized in that, Step S1 includes the following steps: S11. Place the calibrated sensor with traceable measurement values ​​at the loading station of the body scale four-corner deviation testing machine. The calibrated sensor has a pre-stored standard force value. ; S12. The four sets of weight loading devices (2) sequentially drive the weights (4) to apply a load to the calibration sensor. After each set of weights (4) is loaded, the output value of the calibration sensor under that loading is collected synchronously. and the output value of the corresponding monitoring sensor (10) The =1~4, respectively used to identify four sets of weight loading devices (2). S13. Calculate the actual loading coefficient of each weight (4) based on the collected data. = And calculate the actual effective weight of each weight (4) according to the loading coefficient. = ,in The nominal weight of the corresponding weight (4); S14, based on the actual effective weight of each weight (4) and the output value of the corresponding monitoring sensor (10) Calculate the calibration coefficient for each loaded monitoring sensor (10). = Each calibration coefficient This serves as the calibration parameter for the loading force value of the corresponding weight loading device (2).

10. The method for calibrating and applying a loading force value according to claim 9, characterized in that, Step S2 includes the following steps: S21. The weights (4) of the four sets of weight loading devices (2) are driven sequentially to apply a load to the body scale, and the output value of the monitoring sensor (10) of each set of weight loading devices (2) is collected when the load is applied. Then, the calibration coefficients pre-stored in the corresponding weight loading device (2) are called. The actual loading force of the weight loading device (2) was calculated. = × ; S22, based on the actual loading force at the four load-bearing points Based on this, the output value of the body scale is normalized to correct the angle difference of the body scale.

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