A method for compensating for calibration errors in medical device sensors based on electronic measuring instruments

Abstract

This invention relates to the field of medical device sensor calibration and error compensation technology, and particularly to a method for medical device sensor calibration error compensation based on electronic measuring instruments, comprising the following steps: S1, performing multi-measurement topology switching and acquiring bridge circuit signals under zero external load conditions; S2, constructing a topology response vector and identifying electrical parameters; S3, repeatedly identifying and determining compliance ratio coefficients under different constraint conditions; S4, establishing a calibration matrix; S5, online reconstruction compensation to obtain compensated measurement values; S6, reviewing residual projection and selectively updating parameters. This invention achieves differentiated compensation for bridge circuit electrical errors and mechanical errors caused by assembly preload and changes in constraint conditions.

Description

Technical Field

[0001] This invention relates to the field of medical device sensor calibration and error compensation technology, and in particular to a method for medical device sensor calibration error compensation based on electronic measuring instruments. Background Technology

[0002] During operation, the actuators in medical devices typically require force sensors mounted on them to acquire information related to contact force, applied force, or action force to support execution control, status identification, and safety protection. For medical devices employing resistance strain gauge bridge force sensors, the sensor output is affected not only by electrical factors such as bridge excitation, bridge arm parameter deviations, and lead resistance changes, but also by mechanical factors such as the actuator assembly preload, structural constraints, and changes in local contact conditions. Therefore, effectively compensating for the measurement errors of such sensors is one of the technical problems that needs to be solved in this field.

[0003] In the prior art, there are already schemes for calibration and signal simulation of the strain gauge bridge sensor measurement link. For example, Chinese patent application CN111412968A discloses a signal value transmission circuit, key units, and transmission method for a weighing strain gauge sensor. This application describes: first, connecting an unloaded weighing platform and a standard weight through the connection terminals of the measuring strain gauge bridge sensor, recording and storing the relevant calibration parameters of the signal measurement link; then connecting the strain gauge bridge signal measurement terminal and the output simulation terminal, setting the DAC output, recording and storing the relevant calibration parameters of the signal output link and the signal measurement link; subsequently, by setting the DAC output, simulating the state of the weighing platform loaded with an arbitrary weight in real time through the output strain gauge bridge sensor connection terminal. The background section of this application also points out that traditional programmable weighing DC signal simulators mainly simulate strain ratios, and calibration often requires an external high-precision voltmeter to monitor the bridge excitation voltage and equivalent strain signal.

[0004] Therefore, the key technical focus of the aforementioned closest existing technology lies in calibrating the measurement and output links of the Wheatstone strain gauge bridge sensor, and realizing real-time simulation and value transfer of the strain gauge bridge signal based on the calibration results. This solution can solve the problems of strain gauge bridge signal simulation and calibration efficiency, but its technical approach mainly revolves around the overall measurement link calibration, output link calibration, and strain signal simulation. For resistive strain gauge bridge force sensors installed on the actuator of medical devices, in actual operation, the sources of error include not only the electrical deviation of the bridge circuit itself, but also the mechanical deviation caused by the pre-tightening of the actuator assembly, limit contact, and changes in structural constraints. The aforementioned existing technology does not address identifying the sources of electrical error within the bridge circuit by using different measurement topology responses of the same set of bridge arms while keeping the sensor's mechanical state unchanged, nor does it address repeatedly identifying the topology response under different constraint states to further distinguish between electrical and mechanical errors.

[0005] Therefore, based on the above-mentioned closest prior art, the main technical problem to be solved by this application is how to distinguish between the electrical error of the bridge circuit and the mechanical constraint error of the actuator for the resistance strain gauge bridge force sensor installed on the actuator of a medical device, without relying on simple overall link calibration or simple output signal simulation, and to perform more targeted calibration error compensation accordingly. Summary of the Invention

[0006] To overcome the aforementioned technical deficiencies, the present invention aims to provide a method for compensating for calibration errors of medical device sensors based on electronic measuring instruments. This invention identifies electrical parameters by performing multi-measurement topology switching on the same group of bridge arms while keeping the sensor's mechanical state unchanged. This identification is repeated under different constraint states to extract parameters related to assembly preload and compliance changes. Then, based on the projection results of the audit residuals into the electrical and mechanical basis vector sets, the correction matrix is ​​selectively updated, thereby achieving differentiated compensation for bridge circuit electrical errors and mechanical errors caused by assembly preload and constraint state changes.

[0007] This invention discloses a method for compensating for calibration errors of medical device sensors based on electronic measuring instruments. The medical device sensor is a resistance strain gauge bridge force sensor installed on the actuator of the medical device. The electronic measuring instrument includes a bridge topology switching matrix, a dual-mode excitation module, a synchronous sampling module, and a constraint state switching control module. The method includes: S1, when the medical device actuator is in a zero external load state, the same group of bridge arms is sequentially switched to multiple measurement topologies by using the bridge topology switching matrix while keeping the mechanical state of the resistance strain gauge bridge force sensor unchanged. The multiple measurement topologies include at least the first measurement topology, the second measurement topology and the third measurement topology, and the bridge differential output signal, the bridge excitation voltage and the bridge excitation current are collected under each measurement topology. S2, normalize the polarity of the differential output signal of the bridge circuit acquired under each measurement topology, construct the topology response vector, and determine the topology invariant and topology variable based on the topology response vector. Then, determine the bridge arm sensitivity deviation coefficient, lead resistance asymmetry coefficient, and assembly preload coefficient based on the topology invariant and topology variable. S3, under the condition of applying the same reference drive command, the medical device actuator is switched between the first constraint state and the second constraint state by the constraint state switching control module, and S1 and S2 are repeated in the first constraint state and the second constraint state respectively to obtain the first state topological response vector and the second state topological response vector, and the compliance ratio coefficient is determined based on the first state topological response vector and the second state topological response vector. S4. Establish a correction matrix based on the bridge arm sensitivity deviation coefficient, lead resistance asymmetry coefficient, assembly preload coefficient, compliance ratio coefficient, and total bridge resistance coefficient determined by the bridge circuit excitation voltage and bridge circuit excitation current. S5, during the operation of medical equipment, real-time acquisition of the original bridge differential output signal, bridge excitation voltage, bridge excitation current, current constraint status indicator and current load direction indicator of the resistance strain gauge bridge force sensor, and reconstruction compensation of the original bridge differential output signal according to the correction matrix to obtain the compensated measurement value; S6, repeat S1 in the subsequent zero external load audit window, and selectively update the corresponding parameters in the correction matrix based on the projection results of the topology audit residuals obtained from the audit in the electrical basis vector set and the mechanical basis vector set.

[0008] Preferably, in S1, the multiple measurement topologies further include a fourth measurement topology; the first measurement topology and the third measurement topology constitute a first reciprocal topology pair, and the second measurement topology and the fourth measurement topology constitute a second reciprocal topology pair; the first reciprocal topology pair and the second reciprocal topology pair are formed by cyclically changing the connection relationships between the same set of bridge arms and the positive excitation terminal, the negative excitation terminal, the positive signal terminal, and the negative signal terminal.

[0009] Preferably, in S1, under each measurement topology, the dual-mode excitation module sequentially applies constant voltage excitation and constant current excitation to the resistance strain gauge bridge force sensor, and collects constant voltage excitation response signals and constant current excitation response signals respectively; in S2, a mode response matrix is ​​constructed based on the constant voltage excitation response signal and the constant current excitation response signal, and the total bridge resistance coefficient and bridge arm sensitivity deviation coefficient are jointly determined based on the mode response matrix.

[0010] Preferably, in S2, the reciprocal sum component and reciprocal difference component are obtained for the first reciprocal topology pair and the second reciprocal topology pair, respectively; the lead resistance asymmetry coefficient is determined based on the deviation between the reciprocal sum component corresponding to the first reciprocal topology pair and the reciprocal sum component corresponding to the second reciprocal topology pair under constant current excitation; the bridge arm sensitivity deviation coefficient is determined based on the deviation between the reciprocal difference component corresponding to the first reciprocal topology pair and the reciprocal difference component corresponding to the second reciprocal topology pair under constant voltage excitation; and the total bridge resistance coefficient is determined based on the common translation of the reciprocal sum components.

[0011] Preferably, in S1, after each switch from one measurement topology to another, the switching transition segment of the bridge differential output signal is continuously acquired; in S4, a topology switching parasitic response vector is constructed based on the switching transition segment, and the topology switching parasitic coefficient is determined based on the topology switching parasitic response vector; the topology switching parasitic coefficient is incorporated into the correction matrix.

[0012] Preferably, in S3, the first constraint state is the free state of the medical device actuator, and the second constraint state is the constrained state after the medical device actuator is in controlled contact with the calibration limiting member; in both the first and second constraint states, the complete topology acquisition process is repeated after the same reference drive command is applied, so as to obtain the topology response vector of the first state and the topology response vector of the second state respectively.

[0013] Preferably, the same reference drive command is an actuator drive current command with the same integral value, or an actuator drive pulse command with the same number of values; in S3, under the first constraint state and the second constraint state, the bridge differential output signals corresponding to the topology response vectors of the first state and the second state are subjected to polarity normalization and then compared.

[0014] Preferably, in step S3, the first state topology response vector and the second state topology response vector are electrically calibrated using the bridge arm sensitivity deviation coefficient and lead resistance asymmetry coefficient determined in step S2; then, the compliance ratio coefficient is determined based on the proportional relationship between the electrically calibrated first state topology response vector and the second state topology response vector, and the assembly preload coefficient is determined based on the common translation of the state responses of the electrically calibrated first state topology response vector and the second state topology response vector.

[0015] Preferably, in S4, the correction matrix is ​​formed by sequentially combining the electrical correction sub-matrix, the constraint state correction sub-matrix, and the load direction correction sub-matrix; wherein, the electrical correction sub-matrix is ​​constructed based on the bridge arm sensitivity deviation coefficient, the lead resistance asymmetry coefficient, and the total bridge resistance coefficient, the constraint state correction sub-matrix is ​​constructed based on the assembly preload coefficient and the compliance ratio coefficient, and the load direction correction matrix is ​​constructed based on the positive load direction identifier and the reverse load direction identifier, respectively.

[0016] Preferably, in S6, within the zero external load audit window, a complete topology audit is completed sequentially according to the order of the first measurement topology, the second measurement topology, the third measurement topology, and the fourth measurement topology; during the complete topology audit process, the medical device execution unit is kept in the same reference position, and the reciprocal closure residual is calculated based on the first reciprocal topology pair and the second reciprocal topology pair as part of the topology audit residual.

[0017] Preferably, in S6, the topology audit residual is decomposed into reciprocal symmetric residual components and reciprocal antisymmetric residual components, and the reciprocal symmetric residual components are projected onto the electrical basis vector set consisting of the bridge arm sensitivity deviation coefficient, the lead resistance asymmetry coefficient, and the total bridge resistance coefficient, and the reciprocal antisymmetric residual components are projected onto the mechanical basis vector set consisting of the assembly preload coefficient and the compliance ratio coefficient.

[0018] Preferably, the correction matrix includes an electrical correction submatrix and a constraint state correction submatrix; in S6, when the projection magnitude of the topology audit residual on the electrical basis vector set is greater than the first projection threshold and greater than the projection magnitude of the topology audit residual on the mechanical basis vector set, only the electrical correction submatrix is ​​updated; when the projection magnitude of the topology audit residual on the mechanical basis vector set is greater than the second projection threshold and greater than the projection magnitude of the topology audit residual on the electrical basis vector set, only the constraint state correction submatrix is ​​updated.

[0019] Preferably, in S6, when the projection magnitude of the topology audit residual on the electrical basis vector set is greater than the first projection threshold and the projection magnitude on the mechanical basis vector set is greater than the second projection threshold, the topology audit residual is first decomposed into an orthogonal projection along the electrical basis vector set to obtain the electrical update component; then, the remaining residual after removing the electrical update component is decomposed into a second orthogonal projection along the mechanical basis vector set to obtain the mechanical update component; and the electrical correction submatrix and the constraint state correction submatrix are updated according to the electrical update component and the mechanical update component, respectively.

[0020] Preferably, in S6, after the update is completed based on the electrical update component and the mechanical update component, the first state topology response vector and the second state topology response vector are reacquired, and the compliance ratio coefficient is re-determined; when the updated topology audit residual decreases and the change in the re-determined compliance ratio coefficient relative to the compliance ratio coefficient before the update is not greater than the compliance ratio change threshold, the updated correction matrix replaces the current correction matrix.

[0021] Preferably, in S6, when the updated topology audit residual decreases and the change in the redefined compliance ratio coefficient relative to the compliance ratio coefficient before the update is greater than the compliance ratio change threshold, the electrical correction submatrix in the current correction matrix remains unchanged, and the constraint state correction submatrix in the current correction matrix is ​​replaced only with the updated constraint state correction submatrix.

[0022] Compared with existing technologies, the above technical solution has the following advantages: 1. This invention performs multi-measurement topology switching on the same group of bridge arms and combines bridge circuit response under constant voltage excitation and constant current excitation for joint identification. This allows for the differentiation of electrical error factors such as bridge arm sensitivity deviation, lead resistance asymmetry, and overall bridge circuit resistance change. This avoids mixing errors from different sources and helps improve the targeting and accuracy of calibration error compensation for medical device sensors.

[0023] 2. By repeatedly performing topology sampling and parameter identification under the first and second constraint states, and determining the compliance ratio coefficient and assembly preload related parameters based on the response differences between the two states, this invention can distinguish the mechanical errors caused by the assembly preload, limit contact, and constraint state changes of the actuator from the electrical errors of the bridge circuit itself, which helps to reduce the impact of mechanical state changes on the stability of measurement results.

[0024] 3. This invention constructs topological audit residuals and projects the reciprocal symmetric residual components and reciprocal antisymmetric residual components onto the electrical basis vector set and the mechanical basis vector set, respectively. At the same time, it uses the reciprocal closed residual as a consistency modulation term to participate in the update determination. This enables the domain identification of the main sources of current error changes and the targeted updating of the electrical rectifier submatrix or constraint state rectifier submatrix. This helps to reduce the probability of parameter erroneous updates and improve the stability and reliability of the online compensation process.

[0025] 4. This invention divides the correction matrix into an electrical correction sub-matrix, a constraint state correction sub-matrix, and a load direction correction sub-matrix, and combines them in the order of electrical correction first, constraint state correction first, and load direction correction. This makes the compensation process for different types of errors have a clearer hierarchical relationship, which helps to reduce the coupling and superposition between different error sources and improves the interpretability and engineering feasibility of the compensation model.

[0026] 5. By acquiring transition section signals during topology switching, constructing topology switching parasitic response vectors, and determining topology switching parasitic coefficients, this invention can compensate for additional errors caused by the conduction delay of the bridge topology switching matrix, sample-and-hold transients, and connection capacitance effects, which is beneficial to improving the consistency and stability of measurement results under topology switching conditions.

[0027] 6. This invention supports both actuator drive current commands with the same integral value and actuator drive pulse commands with the same number as reference drive methods under two constraint states. This enables actuators of different types of medical devices to complete state comparison and error identification under a unified technical approach, which is beneficial to improving the adaptability of the present invention to medical devices with different drive forms.

[0028] 7. This invention performs a complete topology audit within a zero external load audit window, and reacquires the two-state topology response vectors and redetermines the compliance ratio coefficient after the update. Using the change in compliance ratio and the change in audit residual as the update acceptance conditions, it can suppress the drift caused by unreasonable updates while ensuring the improvement of compensation effect, which is conducive to improving the zero-point stability and parameter retention capability under long-term operating conditions.

[0029] 8. During the loading-unloading process, state switching process, and zero external load holding process, the present invention can simultaneously control nonlinear error, hysteresis error, zero drift and residual error, which is beneficial to improving the accuracy, consistency and long-term reliability of the force detection results of the actuator of medical device, and thus is more suitable for application in medical device scenarios with high requirements for measurement stability. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the system structure of a medical device sensor calibration error compensation method based on electronic measuring instruments according to the present invention; Figure 2 This is a schematic diagram of bridge topology switching and reciprocal topology pairs; Figure 3 This is a schematic diagram of a medical device sensor calibration error compensation method based on electronic measuring instruments according to the present invention. Figure 4 This is a schematic diagram of the first and second constraint states. Figure 5 A schematic diagram of the logic for selectively updating residuals in topology audits; Figure 6 This is a schematic diagram illustrating the relationship between the number of state transitions and the maximum residual error. Figure 7 A comparative curve diagram showing the compensation output for the loading-unloading process; Figure 8This is a schematic diagram showing the relationship between zero external load holding time and zero-point drift. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the accompanying drawings. It should be understood that the following embodiments are only used to illustrate the technical concept and effects of the present invention, and are not intended to limit the scope of protection of the present invention. Equivalent substitutions, customary adjustments, or partial modifications made by those skilled in the art based on the disclosure of this specification without departing from the technical concept of the present invention should all be understood as falling within the scope of the technical idea disclosed in this invention. The following embodiments use an electronic measuring instrument comprising a bridge topology switching matrix, a dual-mode excitation module, a synchronous sampling module, and a constraint state switching control module as the implementation vehicle to describe the method of the present invention.

[0032] It should be noted that the core of this invention does not lie in setting a single bridge circuit parameter or introducing a single update rule, but rather in integrating multi-measurement topology switching of the same group of bridge arms, bridge circuit parameter identification under dual-mode excitation conditions, repeated sampling comparison under different constraint states, distinguishing and modeling bridge circuit electrical errors and actuator mechanical errors, and domain-specific updates based on topology audit residual projection results into a unified whole, so as to achieve calibration error compensation for the resistance strain gauge bridge force sensor installed on the actuator of the medical device. The following embodiments are described around this main theme.

[0033] like Figure 1 As shown, this embodiment uses a calibration error compensation system for a resistance strain gauge bridge force sensor applied to the actuator of a medical device as an example. The medical device actuator can be a surgical instrument operating end, a rehabilitation training contact end, an interventional guide device advancement end, or other medical functional units that require real-time detection of contact force, loading force, and reaction force. The medical device actuator adopts a flexible beam force transmission structure, with a resistance strain gauge bridge force sensor fixedly installed in the high-strain region of the flexible beam. The electronic measuring instrument is located inside the main control system of the medical device, or as an independent module within the medical device housing. The electronic measuring instrument includes a bridge topology switching matrix, a dual-mode excitation module, a synchronous sampling module, and a constraint state switching control module. The bridge topology switching matrix is ​​used to switch the wiring relationship of the same group of bridge arms without changing the mechanical state of the resistance strain gauge bridge force sensor; the dual-mode excitation module is used to output constant voltage excitation and constant current excitation; the synchronous sampling module is used to synchronously acquire the bridge differential output signal, bridge excitation voltage, and bridge excitation current; the constraint state switching control module is used to control the medical device actuator to switch between a first constraint state and a second constraint state.

[0034] In this embodiment, the resistance strain gauge bridge force sensor adopts a four-arm structure, with the same group of arms designated as arm A, arm B, arm C, and arm D. In this embodiment, the arm sensitivity deviation coefficient is denoted as... The lead resistance asymmetry coefficient is denoted as The initial reference value of the assembly preload coefficient is denoted as The assembly preload coefficient, directly determined by the common translation of the state response, is denoted as... Assembly preload consistency deviation is recorded as The compliance ratio is denoted as The total bridge resistance coefficient, directly determined by the reciprocity and component translation, is denoted as... The total bridge resistance consistency check value obtained from the bridge excitation voltage and bridge excitation current is denoted as... The correction matrix is ​​denoted as The positive submatrix of the electrical school is denoted as The constraint state correction submatrix is ​​denoted as The load direction correction sub-matrix is ​​denoted as The topological response vector is denoted as The mode response matrix is ​​denoted as Topology audit residuals are denoted as The reciprocal closed residual is denoted as The reciprocal symmetric residual components are denoted as The reciprocal antisymmetric residual components are denoted as The set of electric basis vectors is denoted as The set of mechanical basis vectors is denoted as The first projection threshold is denoted as The second projection threshold is denoted as The compliance ratio change threshold is denoted as To avoid small constants with zero denominators, denote them as... The parasitic coefficient of topology switching is denoted as The parasitic response vector for topology switching is denoted as The electrical update component is denoted as Mechanical renewal component is denoted as The correction factor of the electrical school's positive submatrix is ​​denoted as The correction amount of the constraint state correction submatrix is ​​denoted as The electrical mapping matrix is ​​denoted as The mechanical mapping matrix is ​​denoted as The current bridge arm equivalent response vector is denoted as The weight vector is read out and denoted as The topological mapping matrix is ​​denoted as The load direction correction factor is denoted as The electrical update step size coefficient is denoted as The mechanical update step size coefficient is denoted as The reciprocal closed-loop uniformity modulation coefficient is denoted as The electrical residual extension vector is denoted as The mechanical residual extension vector is denoted as The drive integral value corresponding to the actuator drive current command with the same integral value is denoted as... The number of pulses corresponding to the same number of actuator drive pulse commands is denoted as The width of a single pulse is denoted as The pulse amplitude is denoted as The pulse period is denoted as The pulse equivalent driving quantity is denoted as .

[0035] like Figure 2 As shown, the bridge topology switching matrix switches the same group of bridge arms to the first, second, third, and fourth measurement topologies. The first and third measurement topologies form the first reciprocal topology pair, and the second and fourth measurement topologies form the second reciprocal topology pair. A reciprocal topology refers to a differential signal output that can be compared and cross-checked under different wiring configurations, achieved by cyclically transposing the connections between the positive excitation terminals, negative excitation terminals, positive signal terminals, and negative signal terminals, without changing the physical position of the bridge arms. Using this method, when the mechanical load remains constant, the output differences under different measurement topologies can more directly reflect the impact of bridge arm parameter asymmetry, lead impedance asymmetry, and changes in the overall bridge resistance on the output.

[0036] like Figure 4 As shown, the constraint state switching control module controls the medical device actuator to switch between a first constraint state and a second constraint state. The first constraint state is a free state, meaning the medical device actuator is not in contact with the calibration limiting member; the second constraint state is a limited state, meaning the medical device actuator is in controlled contact with the calibration limiting member. The calibration limiting member is located outside the reference pose of the medical device actuator and is used to construct a stable and repeatable mechanical constraint boundary. Since the resistance strain gauge bridge force sensor exhibits different structural compliance responses in the free and limited states, the topological response vectors obtained by repeated sampling in both states can be used to further distinguish between the electrical error of the bridge circuit itself and the error caused by changes in the mechanical structure of the actuator.

[0037] In this embodiment, the medical device actuator is first brought into a zero-external-load state. The zero-external-load state satisfies the following conditions: the actuator displacement command has zero increment, the rate of change of the bridge differential output signal within 20ms is no greater than 0.2%FS, and the constraint state switching control module determines that the medical device actuator is not in contact with the calibration limit component. When the above conditions are met, the bridge topology switching matrix sequentially switches the bridge arms to the first measurement topology, the second measurement topology, the third measurement topology, and the fourth measurement topology. The dual-mode excitation module outputs constant voltage excitation and constant current excitation under each measurement topology. In this embodiment, the constant voltage excitation is set to 3.300V, and the constant current excitation is set to 5.000mA. The reason for using both constant voltage and constant current excitation is that constant voltage excitation is more effective in reflecting the impact of inconsistent bridge arm sensitivity on the differential output, while constant current excitation is more effective in reflecting the combined impact of lead impedance changes and overall bridge resistance changes on the excitation and measurement links. The synchronous sampling module acquires 64 sampling points at a sampling frequency of 5kHz for each measurement topology and each excitation mode. After removing the first 8 transition points, the average of the remaining 56 sampling points is taken as the valid measurement result for that state. If topology switching parasitic analysis is used, an additional 1.6ms transition waveform is acquired after each topology switch, corresponding to 8 transition sampling points and 8 post-transition stable sampling points, which are used to construct the topology switching parasitic response vector.

[0038] Under constant voltage excitation mode, the bridge differential output signals corresponding to the four measurement topologies are denoted as follows: , , and The bridge excitation voltages are denoted as follows: , , and In constant current excitation mode, the bridge differential output signals corresponding to the four measurement topologies are denoted as follows: , , and The bridge excitation current is denoted as follows: , , and Since the polarity directions of different measurement topologies may be opposite, the polarity of the differential output signal of the bridge circuit is first normalized. The normalized measurement value under constant voltage excitation mode is calculated according to equation (1): The normalized measurement value under constant current excitation mode is calculated according to equation (2): In the formula, For the first The polarity normalization symbol of a measurement topology, As the reference bridge resistance, in this embodiment, we take... .

[0039] Based on the normalized measurements of the four measurement topologies under constant voltage excitation mode, a topology response vector is constructed. : Simultaneously, a mode response matrix is ​​constructed based on the constant voltage excitation response and the constant current excitation response. : In order to obtain the topological response vector In this embodiment, topological invariants and topological variables are distinguished. Topological invariants are defined as the average translation term shared by the four measurement topologies after polarity normalization, while topological variables are defined as the difference term between reciprocal topological pairs. Topological invariants are calculated according to equation (5): The first topological variable is calculated according to equation (6): The second topological variable is calculated according to equation (7): The third topological variable is calculated according to equation (8): The aforementioned topological invariants and topological variables correspond to the overall translation of the bridge, the difference between the first reciprocal topological pair, the difference between the second reciprocal topological pair, and the overall imbalance information between the two sets of reciprocal topological pairs, respectively, providing a basis for the subsequent separation and identification of electrical and mechanical error parameters.

[0040] Furthermore, under constant current excitation mode, the reciprocity sum and components are obtained for the first and second reciprocity topology pairs respectively. The reciprocity sum and components corresponding to the first reciprocity topology pair are calculated according to equation (9): The reciprocity and components corresponding to the second reciprocal topology are calculated according to equation (10): Under constant voltage excitation mode, the reciprocity difference components are calculated for the first and second reciprocity topology pairs respectively. The reciprocity difference component corresponding to the first reciprocity topology pair is calculated according to equation (11): The reciprocal difference components corresponding to the second reciprocal topological pair are calculated according to equation (12): Lead resistance asymmetry coefficient Calculate according to formula (13): Bridge arm sensitivity deviation coefficient Calculate according to formula (14): To ensure consistency between the process of determining the assembly preload coefficient and the overall technical solution, this embodiment first provides an initial reference value for the assembly preload coefficient based on topological invariants in the step of zero external load and maintaining a constant mechanical state. Initial reference value for assembly preload coefficient. Calculate according to formula (15): In the formula, This is the baseline value of the topological invariants recorded when the equipment is initially assembled and in a standard zero-external-load state. This initial reference value is mainly used for subsequent consistency verification and initial matrix loading, and does not replace the assembly preload coefficient directly determined by the common translation amount of the state response.

[0041] The dominant basis for determining the total bridge resistance coefficient is the common shift of the reciprocal components. The common shift of the reciprocal components is calculated according to equation (16): The total bridge resistance coefficient, directly determined by the reciprocity and component translation, is calculated according to equation (17): In the formula, This represents the reciprocal and component translation amount when the bridge circuit is in its reference state. For consistency verification, the total bridge resistance consistency verification amount is then calculated based on the bridge circuit excitation voltage and current. The total bridge resistance consistency check value is calculated according to formula (18): In the formula, The average bridge excitation voltage of the four measurement topologies in constant current excitation mode is given. Let be the average bridge excitation current of the four measurement topologies in constant current excitation mode. If If the total bridge resistance coefficient is not greater than the total bridge resistance consistency tolerance threshold, then the total bridge resistance coefficient directly determined by the reciprocity and component joint shift is confirmed to be valid; if it exceeds the total bridge resistance consistency tolerance threshold, then a bridge consistency anomaly is recorded and resampling or subsequent review and correction is triggered, but the total bridge resistance coefficient used to construct the correction matrix in the current cycle is still taken as the one directly determined by the reciprocity and component joint shift. Through this process, the reciprocity and component translation amounts constitute the dominant basis for determining the total bridge resistance coefficient, while the bridge excitation voltage and bridge excitation current constitute the basis for its consistency verification.

[0042] To illustrate the specific calculation process, a set of implementation data is given below. Normalized data measured under free conditions for a typical prototype are shown in Table 1.

[0043] Table 1 of multi-measurement topology normalized data in free state Under constant current excitation mode, the reciprocity and components corresponding to the first reciprocal topology pair can be obtained by equation (9): The reciprocity sum and components corresponding to the second reciprocal topology pair can be obtained by equation (10): Therefore, the lead resistance asymmetry coefficient can be obtained from equation (13): That is, under this set of implementation data, the lead resistance asymmetry coefficient is approximately 0.0210.

[0044] Under constant voltage excitation mode, the reciprocity difference component corresponding to the first reciprocity topology pair can be obtained by equation (11): The reciprocal difference components corresponding to the second reciprocal topological pair can be obtained by equation (12): The bridge arm sensitivity deviation coefficient can be obtained from equation (14): Considering that the small amplitude of a single difference component may lead to high coefficient sensitivity, this implementation method further uses the average of 10 rounds of repeated sampling as the final value in engineering applications, and the bridge arm sensitivity deviation coefficient is stabilized at 0.0118.

[0045] Based on the normalized measured values ​​of constant pressure excitation in Table 1, the topological invariants are calculated using equation (5): Assuming the topological invariant baseline values ​​recorded under the initial assembly baseline state Then the initial reference value of the assembly preload coefficient can be obtained from equation (15): That is, the initial reference value of the assembly preload coefficient is approximately 0.0243.

[0046] Furthermore, based on the reciprocity and components in Table 1, if the reciprocity and components recorded under the baseline state are jointly shifted... Then, from equation (16), we can obtain: Then, from equation (17), the total bridge resistance coefficient can be obtained: If the average bridge excitation voltage of the four measurement topologies in constant current excitation mode is 1.771V and the average bridge excitation current is 5.000mA, then the total bridge resistance consistency check value can be obtained from equation (18): If the total bridge resistance consistency tolerance threshold is set to 0.020, then: Therefore, the total bridge resistance coefficient directly determined by the reciprocity and component translation is confirmed to be effective.

[0047] like Figure 4 As shown, after completing multi-measurement topology sampling in the free state, the constraint state switching control module causes the medical device actuator to make controlled contact with the calibration limit component, entering the second constraint state, and then repeats the sampling under the same reference driving conditions. Typical normalized data measured in the limit state are shown in Table 2.

[0048] Table 2 of multi-measurement topology normalized data under limit conditions After obtaining the free-state and constrained-state topological response vectors, the free-state and constrained-state topological response vectors are electrically calibrated using the bridge arm sensitivity deviation coefficient, lead resistance asymmetry coefficient, and total bridge resistance coefficient, resulting in the electrically calibrated first-state and second-state topological response vectors. The norm ratio of the electrically calibrated first-state and second-state topological response vectors reflects the degree of compliance change of the actuator under the two constraint states. The compliance ratio coefficient is calculated according to equation (19): For example, after electrical calibration, the L2 norm of the free-state topological response vector is 1.6194, and the L2 norm of the constrained-state topological response vector is 1.1938. Then: The common translation of the state responses of the two-state topological response vectors after electrical correction is calculated according to equation (20): In the formula, The first state topological response vector after electrical correction is the first... One portion, The second-state topological response vector after electrical correction is the first... There are eight components. Assuming the sum of the eight components after electrical correction is 5.736, then: If the reference value of the common translation amount of the state response after the initial assembly of the equipment is 0.7000, then the assembly preload coefficient directly determined by the common translation amount of the state response is calculated according to formula (21): Substitution , The result was: To perform consistency verification, the assembly preload consistency deviation is then calculated. The assembly preload consistency deviation is calculated according to formula (22): when If the preload consistency tolerance threshold is not greater than the assembly preload consistency tolerance threshold, the assembly preload coefficient directly determined by the common translation of the state response is confirmed to be valid; if it exceeds the assembly preload consistency tolerance threshold, an assembly consistency anomaly is recorded and resampling or subsequent audit correction is triggered, but the assembly preload coefficient used to construct the correction matrix in the current cycle is still the one directly determined by the common translation of the state response. Thus, the common translation amount of the state response forms the direct basis for determining the assembly preload coefficient, while the initial reference value forms the basis for its consistency verification.

[0049] To ensure repeatability of the comparison between the two states when switching between the first and second constraint states, this embodiment employs two equivalent reference driving methods. One method is to use actuator drive current commands with the same integral value, the drive integral value of which is calculated according to equation (23): In the formula, For driving current, For the duration of the drive. Another approach is to use the same number of actuator drive pulse commands, the number of which is expressed according to equation (24): In the formula, This represents the number of effective drive pulses output by the actuator during a single state transition. For ease of comparison, the equivalent drive quantity of the pulses can also be defined and calculated according to equation (25): In the formula, The pulse amplitude of a single driving pulse. This refers to the pulse width of a single drive pulse. It should be understood that when using the same number of actuator drive pulse commands, the comparison benchmark is the number of pulses. The same, but not necessarily required, pulse equivalent driving quantity Completely consistent; the pulse equivalent driving quantity is mainly used for engineering verification and comparability analysis between the pulse scheme and the current integral scheme.

[0050] Under a specific set of parameters in this embodiment, if an actuator drive current command with the same integral value is used, then the drive integral value... Take 0.020 A·s; if the same number of actuator drive pulse commands are used, then the number of pulses... Take 200, single pulse width Take 50 Pulse amplitude Take 0.4A, pulse period Take 1ms. At this time, the equivalent driving quantity of the pulse is: Under this pulse-driven scheme, the first constraint state and the second constraint state are topologically sampled after the same 200 driving pulses. The differential output signals of the bridge corresponding to the two states are first normalized in polarity, and then the topological response vectors of the two states are constructed and compared according to the aforementioned process.

[0051] After obtaining the bridge arm sensitivity deviation coefficient, lead resistance asymmetry coefficient, total bridge resistance coefficient, assembly preload coefficient, and compliance ratio coefficient, a correction matrix is ​​established. The correction matrix consists of an electrical correction submatrix, a constraint state correction submatrix, and a load direction correction submatrix, which satisfy the following relationship: The reason for adopting the above sequence is that: the electrical correction sub-matrix is ​​first used to eliminate the influence of changes in the sensitivity, impedance and overall resistance of the bridge circuit body, so that the subsequent constraint state correction is based on the removal of the main electrical deviations; the constraint state correction sub-matrix is ​​then used to compensate for changes in assembly preload and structural compliance; the load direction correction sub-matrix is ​​finally used to correct the directional differences in positive and negative loads. Therefore, this sequence is more conducive to reducing the coupling superposition between different error sources.

[0052] The positron matrix of the electrical school can be constructed according to equation (27): The constraint state correction submatrix can be constructed according to equation (28): The load direction correction submatrix is ​​selected from the positive load direction submatrix and the negative load direction submatrix based on the current load direction identifier. The positive load direction submatrix and the negative load direction submatrix can be constructed according to equations (29) and (30), respectively: In the formula, The load direction correction factor is preferably set to 0.03 in this embodiment.

[0053] To support the content of parasitic coefficients during topology switching, after each switch from one measurement topology to another, the synchronous sampling module continuously acquires the switching transition segment of the bridge differential output signal. Let the normalized sampling sequence acquired during the switching transition segment be... Then the parasitic response vector of topology switching can be expressed as: The topology switching parasitic coefficient is calculated according to equation (32): In the formula, This is the average of the steady-state normalized values ​​before and after the switch. The topology switching parasitic coefficient is mainly used to compensate for the additional errors caused by the conduction delay of the bridge topology switching matrix, the sample-and-hold transient, and the connection capacitance effect. For example, when switching from the first measurement topology to the second measurement topology, the maximum value of the normalized waveform during the transition is 0.857, the minimum value is 0.801, and the average steady-state value before and after is 0.823. Then, the topology switching parasitic coefficient is: The resulting topology switching parasitic coefficients are incorporated into the electrical school positron matrix to compensate for the parasitic effects caused by the switching transients.

[0054] like Figure 3 As shown, during the online operation phase, the synchronous sampling module acquires in real time the original bridge differential output signal, bridge excitation voltage, bridge excitation current, current constraint status indicator, and current load direction indicator of the resistance strain gauge bridge force sensor. The original bridge differential output signal is denoted as... The bridge excitation voltage is denoted as The bridge excitation current is denoted as Based on the current measurement topology, the original bridge differential output is reconstructed into the current bridge arm equivalent response vector using a pre-established topology mapping matrix. The current bridge arm equivalent response vector is calculated according to equation (33): In the above column vector, the third constant term "1" represents the zero-biased basis term, which reflects the constant basis quantity related to the zero-position bias of the bridge circuit; the fourth constant term "1" represents the topological constant basis term, which reflects the constant basis quantity related to the inherent mapping relationship of the current measurement topology. After completing the construction of the current bridge arm equivalent response vector, the corresponding constraint state correction sub-matrix is ​​selected according to the current constraint state identifier, and the corresponding load direction correction sub-matrix is ​​selected according to the current load direction identifier, and together with the electrical correction sub-matrix, they form the current correction matrix. The compensated measured value is calculated according to equation (34): The readout weight vector is obtained by linearly fitting multiple sets of samples between the standard loading value and the current bridge arm's equivalent response vector. Specifically, the standard loading value and the current bridge arm's equivalent response vector satisfy a linear approximation relationship. The readout weight vector that minimizes the prediction output error is obtained using the least squares method and is then used as the readout weight vector.

[0055] To ensure parameter stability during long-term operation, this implementation method sets a zero-external-load audit window and initiates the audit each time the device completes an operation cycle and returns to the reference pose. During the audit, the bridge topology switching matrix completes a full topology audit in the order of the first measurement topology, the second measurement topology, the third measurement topology, and the fourth measurement topology, and keeps the medical device actuator in the same reference position throughout the audit process. The reciprocal closure residual between the first reciprocal topology pair and the second reciprocal topology pair is calculated according to equation (35): In the formula, , , and The normalized audit values ​​are the four measurement topologies corresponding to the audit window. To further distinguish between electrical and mechanical sources in the audit residuals, the topology audit residuals are decomposed into reciprocal symmetric residual components and reciprocal antisymmetric residual components. The reciprocal symmetric residual components are calculated according to equation (36): The reciprocal antisymmetric residual components are calculated according to equation (37): In order to explicitly include the reciprocal closure residual as part of the topology audit residual and connect it with the subsequent update logic, this implementation defines the topology audit residual as a combined residual vector containing the reciprocal closure residual, the reciprocal symmetric residual component, and the reciprocal antisymmetric residual component, as expressed by equation (38): Among them, the reciprocal closed residual is used to characterize the overall closure consistency between two sets of reciprocal topological pairs. The reciprocal symmetric residual component mainly reflects the unbalanced changes on the electrical side, and the reciprocal antisymmetric residual component mainly reflects the unbalanced changes on the mechanical side. In order to make the subsequent projection processing correspond one-to-one with the above residual components, the electrical residual expansion vector and the mechanical residual expansion vector are further defined. The electrical residual expansion vector is composed of the reciprocal symmetric residual components, and is expressed according to equation (39): The mechanical residual extension vector is composed of reciprocal antisymmetric residual components, as expressed by equation (40): The electrical basis vector set includes three unit basis vectors corresponding to the bridge arm sensitivity deviation coefficient, lead resistance asymmetry coefficient, and total bridge resistance coefficient, respectively; the mechanical basis vector set includes two unit basis vectors corresponding to the assembly preload coefficient and compliance ratio coefficient, respectively. To illustrate their origin, in this embodiment, each unit basis vector in the electrical basis vector set is obtained by normalizing and orthogonalizing the first-order sensitivity samples of the compensation output based on the bridge arm sensitivity deviation coefficient, lead resistance asymmetry coefficient, and total bridge resistance coefficient, respectively. Similarly, each unit basis vector in the mechanical basis vector set is obtained by normalizing and orthogonalizing the first-order sensitivity samples of the compensation output based on the assembly preload coefficient and compliance ratio coefficient, respectively.

[0056] To ensure that the technical actions of projecting reciprocal symmetric and reciprocal antisymmetric residual components separately meet the overall audit consistency requirements simultaneously, this implementation introduces the reciprocal closed residual as a consistency modulation term into the calculation of the projection magnitude. The projection magnitude of the topology audit residual on the set of electrical basis vectors. Calculate according to formula (41): The projection magnitude of the topology audit residual onto the set of mechanical basis vectors Calculate according to formula (42): In the formula, The reciprocal closed-loop uniformity modulation coefficient is preferably set to 0.5 in this embodiment; The first in the set of electric basis vectors Unit basis vectors, The first in the set of mechanical basis vectors There are one unit basis vector. Using the above method, the reciprocal symmetric residual components are projected onto the electrical basis vector set, and the reciprocal antisymmetric residual components are projected onto the mechanical basis vector set. The reciprocal closed residuals then influence both projection results through a consistency modulation term, thus simultaneously satisfying the requirements for audit consistency and domain-specific updates.

[0057] like Figure 5 As shown, when the projection magnitude of the topology audit residual on the electrical basis vector set is greater than the first projection threshold and greater than the projection magnitude on the mechanical basis vector set, only the electrical corrector submatrix is ​​updated; when the projection magnitude of the topology audit residual on the mechanical basis vector set is greater than the second projection threshold and greater than the projection magnitude on the electrical basis vector set, only the constraint state corrector submatrix is ​​updated. To illustrate the specific effects of electrical-only and mechanical-only updates, this embodiment provides the following numerical examples: In a single electrical-only update process, before the update, the arm sensitivity deviation coefficient is 0.0118, the lead resistance asymmetry coefficient is 0.0210, and the total bridge resistance coefficient is 0.0272; after the update, the arm sensitivity deviation coefficient becomes 0.0109, the lead resistance asymmetry coefficient becomes 0.0187, and the total bridge resistance coefficient becomes 0.0248, while the assembly preload coefficient and compliance ratio coefficient remain unchanged. In a mechanical-only update, the pre-update assembly preload coefficient was 0.0243, and the compliance coefficient was 1.3567. After the update, the assembly preload coefficient became 0.0218, and the compliance coefficient became 1.3325, while the bridge arm sensitivity deviation coefficient, lead resistance asymmetry coefficient, and total bridge resistance coefficient remained unchanged. This update method can reduce the impact of electrical and mechanical errors on the overall output, respectively.

[0058] When the projection magnitudes of the topology audit residuals on both the electrical basis vector set and the mechanical basis vector set exceed the threshold, a first orthogonal projection decomposition is performed on the topology audit residuals along the electrical basis vector set to obtain the electrical update component. Then, a second orthogonal projection decomposition is performed on the remaining residuals after removing the electrical update component along the mechanical basis vector set to obtain the mechanical update component. To maintain consistency with the aforementioned definition of separate projections, in this embodiment, the first orthogonal projection decomposition is applied to the electrical residual extension vector, and the second orthogonal projection decomposition is applied to the mechanical residual extension vector after reciprocal closed-loop consistency modulation. The electrical update component is calculated according to equation (43): The remaining mechanical residual vector after removing the electrical update component is expressed according to equation (44): The mechanical replacement component is calculated according to formula (45): After adopting the above expression, the sources of the electrical update component and the mechanical update component are consistent with the aforementioned definition of the projection modulus, while the reciprocal closure residual still participates in the consistency modulation as part of the topology audit residual.

[0059] To explain the source of the matrix corrections in the update formula, the electrical correction submatrix correction represents the matrix increment derived from the electrical update component through the electrical mapping matrix, and the constraint state correction submatrix correction represents the matrix increment derived from the mechanical update component through the mechanical mapping matrix. They are calculated according to equations (46) and (47), respectively: The electrical mapping matrix is ​​obtained by normalizing the sensitivity matrix of the compensation output with respect to the bridge arm sensitivity deviation coefficient, lead resistance asymmetry coefficient, and total bridge resistance coefficient. The mechanical mapping matrix is ​​obtained by normalizing the sensitivity matrix of the compensation output with respect to the assembly preload coefficient and compliance ratio coefficient. The update of the electrical positron matrix is ​​performed according to equation (48): The constraint state correction submatrix is ​​updated according to equation (49): After completing the above update, the system reacquires the first-state topology response vector and the second-state topology response vector, and redetermines the compliance ratio coefficient. If the updated topology audit residual decreases, and the change in the redetermined compliance ratio coefficient relative to the previous compliance ratio coefficient is not greater than the compliance ratio change threshold, then the updated correction matrix replaces the current correction matrix. To explicitly support this determination process, this implementation provides a set of examples: if the compliance ratio coefficient before the update is 1.3567 and the updated compliance ratio coefficient is 1.3789, then the change is 0.0222, which is less than the compliance ratio change threshold of 0.060, therefore the overall replacement is accepted; if the compliance ratio coefficient before the update is 1.3567 and the updated compliance ratio coefficient is 1.4380, then the change is 0.0813, which is greater than the compliance ratio change threshold of 0.060. In this case, although the audit residual decreases, only the constraint state correction sub-matrix is ​​replaced, while the electrical correction sub-matrix remains unchanged.

[0060] To make the above technical solution more concrete, this embodiment provides a set of test parameters. The range of the medical device actuator is set to 0N to 10N, and the bridge reference resistance is 350Ω. The topology switching cycle is 4ms, the complete topology review window duration is 20ms, and the reference drive current integral value is under the first constraint state. Take 0.020 A·s; under the pulse drive scheme, the number of reference pulses is... Take 200, single pulse width Take 50 Pulse amplitude Take 0.4A, pulse period The time interval is 1ms. The ambient temperature is controlled at 25℃±1℃, the relative humidity is controlled at 45%±5%, the sampling board resolution is 24bit, and the controlled contact stroke of the calibration limit component is 0.35mm. Table 3 lists the main structure and test parameters in this embodiment.

[0061] Table 3 Main Structure and Test Parameters This embodiment includes a comparative example. The comparative prototype uses the aforementioned flexible beam and Wheatstone full-bridge structure, but only employs conventional zero-point to full-scale two-point static calibration and a single overall correction parameter method for compensation. It does not perform multi-measurement topology transposition identification, repeated identification under different constraint states, or selective updates based on residual projection. During testing, both the prototype in this embodiment and the comparative prototype use the same batch of bridge force sensors, the same batch of flexible beams, the same assembly process, and the same testing platform. Each test group is repeated three times, and the data in the table is the average of the three test results; for the "maximum residual error" item, the maximum value among the three tests is used.

[0062] Under the same measurement range, structural dimensions, installation process, and test platform conditions, 10 independent tests were conducted on the prototype of this embodiment and the comparative prototype. Each test included 1000 cycles of switching between free and limited states, 20 full-scale reciprocating loading cycles, and a 120-minute zero-external-load holding test. The test statistics are shown in Table 4.

[0063] Table 4 of the experimental comparison results To further illustrate the technical effects of the present invention, Figure 6 A schematic diagram of the relationship between the number of state transitions and the maximum residual error is given, and the corresponding basic data is shown in Table 5. Figure 6 The data in Table 5 is used to create the plot. Figure 6 The horizontal axis represents the number of state transitions, and the vertical axis represents the maximum residual error. Figure 6 This invention is primarily used to illustrate its ability to suppress the accumulation of residual errors after prolonged and repeated state switching. Figure 6 As shown in Table 5, the maximum residual error of the comparative prototype continued to rise with the number of state switching, reaching 2.26%FS after 1000 switching cycles; while the prototype of this embodiment showed a significantly smaller increase under the same conditions, stabilizing at about 0.49%FS after 1000 switching cycles. This indicates that the multi-measurement topology identification and selective update mechanism has a significant effect on suppressing the accumulation of residual errors during long-term operation.

[0064] Table 5: Number of State Switching Counts and Maximum Residual Error Figure 7 A schematic diagram of the compensation output comparison curves during the loading-unloading process is provided, and the corresponding basic data is shown in Table 6. Figure 7 The data in Table 6 is used to create the plot. Figure 7 The horizontal axis represents the standard load value, and the vertical axis represents the compensated output value. Figure 7 This is mainly used to illustrate the improvement effect of the present invention on nonlinear error and hysteresis error. Figure 7 It can be seen that the comparative prototype deviates significantly from the ideal output curve during loading and unloading, and a wide hysteresis loop forms between the loading and unloading curves. In contrast, the loading and unloading curves of the prototype in this embodiment are closer to the ideal output curve, and the loop width is significantly reduced. This indicates that by separating and modeling the bridge circuit electrical error and mechanical constraint error, and utilizing the combined effects of load direction correction and constraint state correction, nonlinear error and hysteresis error can be effectively reduced.

[0065] Loading-unloading process output data table 6 Figure 8 A schematic diagram of the relationship between zero external load holding time and zero drift is given, and the corresponding basic data is shown in Table 7. Figure 8 The data in Table 7 is used to create the plot. Figure 8 The horizontal axis represents the zero external load holding time, and the vertical axis represents the zero-point drift. Figure 8 This is mainly used to illustrate the zero-point stability of the present invention after prolonged static placement or repeated operation. Figure 8 It can be seen that the zero-point drift of the comparative prototype gradually increased during the 120-minute zero-load holding test, while the zero-point drift growth rate of the prototype in this embodiment was significantly lower, eventually remaining within a small range. This indicates that the electrical and mechanical calibration domain update mechanism adopted in this embodiment can maintain the zero-point state more stably after the equipment has been idle for a long time or repeatedly run.

[0066] Table 7 Zero-load hold-up time and zero-point drift In another embodiment, the bridge topology switching matrix only switches to the first, second, and third measurement topologies. A set of reciprocal relationships formed by the first and third measurement topologies, along with the second measurement topology as an auxiliary topology, is used to complete the basic identification. Specifically, in this simplified embodiment, the reciprocal difference between the first and third measurement topologies is used to obtain information related to bridge arm sensitivity deviation. The reciprocity and components between the first and third measurement topologies, combined with the normalized measurement value of the second measurement topology, are used to estimate lead resistance asymmetry and overall bridge resistance change. The second measurement topology mainly serves as an auxiliary correction and constraint discrimination mechanism. The fourth measurement topology does not participate in the initial modeling but can be selectively introduced only as a verification topology during the review stage, or omitted in scenarios with higher real-time requirements. The dual-mode excitation module still outputs constant voltage and constant current excitations; the constraint state switching control module still controls the switching between free and limited states; however, during the review update stage, the two-stage orthogonal projection decomposition is not performed. Instead, the electrical correction submatrix or the constraint state correction submatrix is ​​updated based solely on the magnitude of the projection modulus of the topology review residuals onto the electrical and mechanical basis vector sets. While this simplified implementation method is less complex in terms of identification dimensions and update complexity than the aforementioned complete implementation method, it still retains the core technical concepts of "multi-measurement topology transposition identification, electrical and mechanical error differentiation, and selective updating based on audit residual projection." Therefore, it can still achieve targeted compensation for bridge circuit electrical and mechanical constraint errors. This simplified implementation method is applicable to medical device scenarios with small measurement ranges, high real-time requirements, or limited hardware resources.

[0067] The above embodiments are merely preferred embodiments of the present invention. For those skilled in the art, any conventional adjustments made to bridge excitation parameters, sampling frequency, topology switching period, projection threshold, compliance ratio change threshold, reciprocal closure consistency modulation coefficient, update step size coefficient, reference drive integral value, number of reference pulses, and pulse parameters, or equivalent substitutions made to the form of the medical device actuator, the form of the calibration limiting component, and the load direction correction method, without departing from the technical concept of the present invention, should be understood as falling within the scope of the technical concept disclosed in this specification.

Claims

1. A method for compensating for calibration errors of medical device sensors based on electronic measuring instruments, characterized in that, The medical device sensor is a resistance strain gauge bridge force sensor installed on the actuator of the medical device. The electronic measuring instrument includes a bridge topology switching matrix, a dual-mode excitation module, a synchronous sampling module, and a constraint state switching control module. The method includes: S1, when the medical device actuator is in a zero external load state, the same group of bridge arms is sequentially switched to multiple measurement topologies by the bridge topology switching matrix while keeping the mechanical state of the resistance strain gauge bridge force sensor unchanged. The multiple measurement topologies include at least a first measurement topology, a second measurement topology, and a third measurement topology, and the bridge differential output signal, bridge excitation voltage, and bridge excitation current are collected under each measurement topology. S2, normalize the polarity of the differential output signal of the bridge circuit acquired under each measurement topology, construct the topology response vector, and determine the topology invariant and topology variable based on the topology response vector. Determine the bridge arm sensitivity deviation coefficient, lead resistance asymmetry coefficient and assembly preload coefficient based on the topology invariant and topology variable. S3, under the condition of applying the same reference drive command, the constraint state switching control module is used to switch the medical device execution unit between the first constraint state and the second constraint state, and S1 and S2 are repeated in the first constraint state and the second constraint state respectively to obtain the first state topological response vector and the second state topological response vector, and the compliance ratio coefficient is determined according to the first state topological response vector and the second state topological response vector. S4. Establish a correction matrix based on the bridge arm sensitivity deviation coefficient, the lead resistance asymmetry coefficient, the assembly preload coefficient, the compliance ratio coefficient, and the total bridge resistance coefficient determined by the bridge circuit excitation voltage and the bridge circuit excitation current. S5. During the operation of the medical equipment, the original bridge differential output signal, bridge excitation voltage, bridge excitation current, current constraint state indicator and current load direction indicator of the resistance strain gauge bridge force sensor are collected in real time. The original bridge differential output signal is reconstructed and compensated according to the correction matrix to obtain the compensated measurement value. S6, S1 is repeated in the subsequent zero external load audit window, and the corresponding parameters in the correction matrix are selectively updated according to the projection results of the topology audit residuals obtained from the audit in the electrical basis vector set and the mechanical basis vector set.

2. The method for compensating for calibration errors of medical device sensors based on electronic measuring instruments according to claim 1, characterized in that, In S1, the plurality of measurement topologies further includes a fourth measurement topology; the first measurement topology and the third measurement topology constitute a first reciprocal topology pair, and the second measurement topology and the fourth measurement topology constitute a second reciprocal topology pair; the first reciprocal topology pair and the second reciprocal topology pair are formed by cyclically changing the connection relationships between the same group of bridge arms and the positive excitation terminal, negative excitation terminal, positive signal terminal and negative signal terminal.

3. The method for compensating for calibration errors of medical device sensors based on electronic measuring instruments according to claim 2, characterized in that, In S1, under each of the measurement topologies, the dual-mode excitation module sequentially applies constant voltage excitation and constant current excitation to the resistance strain gauge bridge force sensor, and acquires constant voltage excitation response signal and constant current excitation response signal respectively. In S2, a mode response matrix is ​​constructed based on the constant voltage excitation response signal and the constant current excitation response signal, and the total bridge resistance coefficient and the bridge arm sensitivity deviation coefficient are jointly determined based on the mode response matrix.

4. The method for compensating for calibration errors of medical device sensors based on electronic measuring instruments according to claim 3, characterized in that, In S2, the reciprocity sum component and reciprocity difference component are obtained for the first reciprocal topology pair and the second reciprocal topology pair, respectively; the lead resistance asymmetry coefficient is determined based on the deviation between the reciprocity sum component corresponding to the first reciprocal topology pair and the reciprocity sum component corresponding to the second reciprocal topology pair under constant current excitation; the bridge arm sensitivity deviation coefficient is determined based on the deviation between the reciprocity difference component corresponding to the first reciprocal topology pair and the reciprocity difference component corresponding to the second reciprocal topology pair under constant voltage excitation; and the total bridge resistance coefficient is determined based on the common translation of the reciprocity sum component.

5. The method for compensating for calibration errors of medical device sensors based on electronic measuring instruments according to claim 4, characterized in that, In S1, after each switch from one measurement topology to another, the switching transition segment of the bridge differential output signal is continuously acquired; in S4, a topology switching parasitic response vector is constructed based on the switching transition segment, and the topology switching parasitic coefficient is determined based on the topology switching parasitic response vector. The parasitic coefficients of topology switching are incorporated into the correction matrix.

6. The method for compensating for calibration errors of medical device sensors based on electronic measuring instruments according to claim 1, characterized in that, In S3, the first constraint state is the free state of the medical device actuator, and the second constraint state is the constrained state after the medical device actuator is in controlled contact with the calibration limiting member. In both the first and second constraint states, the complete topology acquisition process is repeated after the same reference drive command is applied to obtain the topology response vector of the first state and the topology response vector of the second state, respectively.

7. The method for compensating for calibration errors of medical device sensors based on electronic measuring instruments according to claim 6, characterized in that, The same reference drive command is either an actuator drive current command with the same integral value or an actuator drive pulse command with the same number of values. In S3, under the first constraint state and the second constraint state, the bridge differential output signals corresponding to the topology response vectors of the first state and the second state are subjected to polarity normalization and then compared.

8. The method for compensating for calibration errors of medical device sensors based on electronic measuring instruments according to claim 7, characterized in that, In step S3, the first state topology response vector and the second state topology response vector are electrically calibrated using the bridge arm sensitivity deviation coefficient and the lead resistance asymmetry coefficient determined in step S2; then, the compliance ratio coefficient is determined based on the proportional relationship between the electrically calibrated first state topology response vector and the second state topology response vector, and the assembly preload coefficient is determined based on the common translation of the state responses of the electrically calibrated first state topology response vector and the second state topology response vector.

9. The method for compensating for calibration errors of medical device sensors based on electronic measuring instruments according to claim 8, characterized in that, In S4, the correction matrix is ​​formed by sequentially combining the electrical correction sub-matrix, the constraint state correction sub-matrix, and the load direction correction sub-matrix; wherein, the electrical correction sub-matrix is ​​constructed based on the bridge arm sensitivity deviation coefficient, the lead resistance asymmetry coefficient, and the total bridge resistance coefficient, the constraint state correction sub-matrix is ​​constructed based on the assembly preload coefficient and the compliance ratio coefficient, and the load direction correction sub-matrix is ​​constructed based on the positive load direction identifier and the reverse load direction identifier, respectively.

10. The method for compensating for calibration errors of medical device sensors based on electronic measuring instruments according to claim 2, characterized in that, In S6, within the zero external load audit window, a complete topology audit is completed sequentially according to the order of the first measurement topology, the second measurement topology, the third measurement topology, and the fourth measurement topology. During the complete topology audit, the medical device execution unit is kept in the same reference position, and the reciprocal closure residual is calculated based on the first reciprocal topology pair and the second reciprocal topology pair as part of the topology audit residual.

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