A calibration device for a bionic petal-shaped elastomer six-dimensional force sensor

Abstract

This invention discloses a calibration device for a six-dimensional force sensor of a biomimetic petal-shaped elastomer, belonging to the field of sensor calibration technology. Addressing the technical problems of existing calibration equipment being unable to adapt to the irregular structure of biomimetic petal-shaped elastomers, suffering from severe dimensional coupling interference, low calibration accuracy, and poor adaptability to operating conditions, this invention employs a dedicated adaptive stress-free clamping module to achieve precise, stress-free clamping of the petal-shaped sensor. Through six independent linear and rotational loading units, it can complete single-dimensional independent loading and multi-dimensional coupled loading of three-dimensional forces and moments. Combined with a high-precision force value detection feedback module and an intelligent decoupling calibration algorithm, it effectively eliminates dimensional coupling interference and equipment errors, accurately calibrating core parameters such as sensor sensitivity, linearity, and coupling error. This device features a stable structure, strong adaptability, and a high degree of automation. It can realistically simulate the actual working force state of the sensor, significantly improving the calibration accuracy and efficiency of the six-dimensional force sensor of the biomimetic petal-shaped elastomer. It is suitable for high-precision batch calibration of various sensors with the same structure and has broad application prospects.

Description

Technical Field

[0001] This invention relates to the field of sensor calibration technology, and more specifically to a calibration device for a biomimetic petal-shaped elastomer six-dimensional force sensor. Background Technology

[0002] Six-dimensional force sensors can simultaneously detect three-dimensional forces and three-dimensional torques in space, and are widely used in fields such as precision robot control, precision industrial assembly, aerospace attitude detection, and force sensing in intelligent prosthetics. The biomimetic petal-shaped elastomer six-dimensional force sensor uses a biomimetic petal-shaped flexible elastomer as its core force and strain transmission structure. It boasts advantages such as high flexibility, high sensitivity, lightweight structure, and conformity to biomimetic motion characteristics. Compared to traditional rigid elastomer six-dimensional force sensors, it is more suitable for emerging scenarios such as flexible robots, biomimetic actuators, and human-computer interaction devices.

[0003] Sensor calibration is a core step in ensuring its detection accuracy. Through precise calibration, key parameters such as sensor sensitivity, linearity, coupling error, and repeatability can be determined, enabling accurate mapping between sensor input load and output signal. Current six-dimensional force sensor calibration devices are mostly designed for traditional crossbeam and cylindrical rigid elastomer sensors, which have many compatibility defects: First, existing clamping structures are mostly general-purpose rigid fixtures, which cannot be adapted to biomimetic petal-shaped irregular curved surface structures. The clamping process is prone to local extrusion stress and positioning offset, and residual stress will seriously interfere with calibration data, resulting in a decrease in calibration accuracy. Second, existing calibration equipment often suffers from dimensional coupling interference problems. The loading process of each dimension affects each other, making it impossible to achieve accurate independent loading of a single dimension, and making it difficult to accurately detect the dimensional coupling error of the petal-shaped elastomer. Third, for the flexible force characteristics of flexible petal-shaped elastomers, existing rigid loading methods are prone to causing excessive deformation and uneven force on the elastomer, which cannot simulate the actual working force state of the sensor, and the calibration results deviate significantly from the actual working conditions. Fourth, existing equipment has a low degree of automation, relying heavily on manual step-by-step loading, reading, and recording, resulting in low calibration efficiency, large human error, and difficulty in meeting the needs of batch sensor calibration.

[0004] In summary, the current lack of a dedicated device that is specifically adapted to biomimetic petal-shaped elastomer six-dimensional force sensors, and can achieve precise six-dimensional decoupling, stress-free clamping, and automated and efficient calibration, restricts the industrial application and accuracy improvement of this type of novel flexible six-dimensional force sensor. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a calibration device for a biomimetic petal-shaped elastomer six-dimensional force sensor. This device solves the technical problems of poor adaptability, severe coupling interference, low calibration accuracy, and insufficient automation in existing calibration equipment, thereby achieving high-precision, automated, and full-dimensional calibration of the biomimetic petal-shaped elastomer six-dimensional force sensor.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A calibration device for a six-dimensional force sensor using a biomimetic petal-shaped elastomer includes a frame module, a multi-dimensional precision loading module, a force value detection and feedback module, a sensor clamping and positioning module, and an intelligent control calibration module. The frame module provides stable support for the entire device, ensuring structural stability during the calibration process. The sensor clamping and positioning module is specifically adapted to the irregular structure of the biomimetic petal-shaped elastomer, achieving stress-free precision clamping and positioning, eliminating clamping errors. The multi-dimensional precision loading module has six independent loading units, corresponding to three-dimensional forces and three-dimensional moments respectively, enabling single-dimensional independent loading and multi-dimensional synchronous coupled loading. The force value detection and feedback module collects standard loading parameters for each dimension in real time with high precision, forming a closed-loop feedback. The intelligent control calibration module achieves fully automated control, data decoupling, parameter calculation, and report generation throughout the entire process.

[0007] Furthermore, the sensor clamping and positioning module adopts an adaptive irregular-shaped card holder structure, combined with a flexible buffer pad layer and a multi-point uniform locking structure, which perfectly fits the contour of the petal-shaped elastomer, avoids residual stress caused by rigid compression, and ensures positioning accuracy, eliminating the interference of clamping on calibration results from the source.

[0008] Furthermore, the linear loading unit and the rotary loading unit of the multidimensional precision loading module are independent of each other and do not interfere with each other. The loading end adopts a flexible floating joint structure, which is adapted to the force characteristics of the flexible petal elastomer, avoids local stress concentration, simulates the actual working force state of the sensor, and improves the accuracy of calibration.

[0009] Furthermore, the device incorporates a proprietary six-dimensional decoupling calibration algorithm, which can effectively remove coupling interference from various dimensions, accurately calculate the inherent coupling error of the sensor, achieve high-precision parameter calibration, and solve the problem that traditional equipment cannot accurately detect coupling errors.

[0010] Compared with the prior art, the present invention has the following advantages: 1. It is specifically adapted to the biomimetic petal-shaped elastomer structure and adopts a special adaptive stress-free clamping structure, which completely solves the problems of poor adaptability, easy generation of residual stress and low positioning accuracy of traditional clamps, and greatly improves the accuracy of calibration foundation.

[0011] 2. The six-dimensional loading unit is independently controllable, enabling precise independent calibration in a single dimension and coupled calibration in multiple dimensions. Combined with closed-loop feedback and decoupling algorithms, it effectively eliminates coupling interference between dimensions, accurately detects various error parameters of the sensor, and achieves calibration accuracy far exceeding that of traditional general-purpose calibration equipment.

[0012] 3. The flexible loading method is adapted to the stress characteristics of the flexible elastomer, which can truly simulate the stress state of the sensor under actual working conditions. The calibration results are consistent with the actual application scenario and have higher reliability.

[0013] 4. Fully automated control, the entire process of loading, data acquisition, decoupling, calculation, and report generation can be completed without manual intervention, which greatly improves calibration efficiency, reduces human error, and meets the needs of batch sensor calibration. Detailed Implementation

[0014] The present invention will be further described in detail below with reference to specific embodiments.

[0015] The present invention discloses a calibration device for a biomimetic petal-shaped elastomer six-dimensional force sensor, the core of which consists of a frame module, a multi-dimensional precision loading module, a force value detection and feedback module, a sensor clamping and positioning module, and an intelligent control calibration module.

[0016] The frame module adopts an integrated cast aluminum rigid frame, which has undergone aging stress relief treatment to eliminate the risk of assembly deformation. The mounting reference surfaces of each functional module are machined to IT6 level accuracy, ensuring the coaxiality and perpendicularity accuracy of each loading unit, thus guaranteeing calibration stability and accuracy from the hardware structure. The frame adopts a closed frame structure, which has strong resistance to external vibration and environmental interference, and can be adapted to long-term high-precision calibration operations in the laboratory.

[0017] The sensor clamping and positioning module, as the core adaptable structure of this invention, includes a fixed base, an adaptive positioning bracket, a flexible buffer layer, and a locking and limiting assembly. The fixed base is detachably bolted to the frame, allowing for quick replacement of the positioning bracket to accommodate different specifications of petal-shaped sensors. The adaptive positioning bracket is custom-designed based on the curved contour and petal distribution angle of the biomimetic petal elastomer, perfectly conforming to the sensor's shape and structure. A 0.5-1mm thick flexible silicone buffer layer is laid on the contact surface of the bracket to prevent deformation and residual stress caused by rigid contact compressing the elastomer. The locking and limiting assembly uses four sets of evenly distributed fine-tuning locking bolts, ensuring uniform force during locking and achieving precise sensor positioning and fixation. This guarantees that the sensor's force center and loading center are completely aligned, eliminating calibration errors caused by eccentric force.

[0018] The multi-dimensional precision loading module comprises X, Y, and Z-axis linear force loading units and a three-axis torque loading unit, with six units independently driven and coordinated for control. The linear loading unit uses a high-precision servo electric cylinder as its power source, with a loading stroke accuracy of ±0.01mm and a loading force range of 0-500N, suitable for calibration of small-to-medium range biomimetic six-dimensional force sensors. The electric cylinder output is equipped with a floating universal joint, which can automatically fine-tune the loading angle to ensure that the loading force acts perpendicularly on the sensor's force-bearing surface, avoiding lateral force interference. The rotary loading unit uses a precision servo rotary platform with a rotation angle accuracy of ±0.001° and a torque loading range of 0-50N·m, accurately outputting quantitative torque loads in each dimension. Each loading unit can be started and stopped independently, and the loading rate and amplitude can be adjusted independently, meeting the requirements of single-dimensional static calibration, dynamic cyclic calibration, and multi-dimensional coupled working condition calibration.

[0019] The force detection feedback module consists of a high-precision six-dimensional standard force sensor, a signal filtering and amplification unit, and a high-speed data acquisition card. The standard force sensor has an accuracy level two levels higher than the sensor to be calibrated, ensuring the accuracy of the calibration reference. The signal filtering and amplification unit can effectively filter environmental electromagnetic interference and mechanical vibration interference, optimizing the quality of the acquired signal. The data acquisition card has a sampling frequency of no less than 1000Hz, enabling real-time and continuous acquisition of applied force, torque, displacement, and angle data in various dimensions, which are synchronously transmitted to the intelligent control calibration module.

[0020] The intelligent control calibration module uses an industrial touch screen all-in-one machine as the control terminal, and incorporates a dedicated calibration control system and a six-dimensional decoupling algorithm. The system has a pre-set standardized calibration process that can automatically complete the entire workflow, including equipment self-test, zero-point calibration, stepped loading, data acquisition, error decoupling, parameter fitting, and report generation. Targeting the flexible deformation characteristics of biomimetic petal-shaped elastomers, the system incorporates a deformation compensation model that can correct force deviations based on loaded displacement data, further improving calibration accuracy. Simultaneously, the system supports custom calibration parameters, adapting to the calibration needs of six-dimensional force sensors with different ranges and specifications of biomimetic petal-shaped elastomers.

[0021] The specific procedure for sensor calibration using this device is as follows: First, the equipment undergoes a power-on self-test. The control system automatically detects the operating and communication status of each loading unit and detection module. After confirming that the equipment is fault-free, it enters calibration mode. Then, the sensor to be calibrated is placed in the adaptive positioning holder, and its position is fine-tuned to ensure complete contact with the holder. The locking bolts are then tightened evenly to complete stress-free clamping. After clamping, a zero-point calibration operation is performed on the control system interface to zero all initial parameters in all dimensions and eliminate initial equipment errors.

[0022] The calibration phase is divided into single-dimensional independent calibration and multi-dimensional coupled calibration. During single-dimensional calibration, the X, Y, and Z-axis forces and torques are applied independently in a stepped manner, with 5-10 steps per dimension. Each load is held for 3-5 seconds, and standard load data and sensor output voltage signals are collected simultaneously. After loading is complete, the load is unloaded step by step. After single-dimensional calibration, the multi-dimensional coupled calibration program is initiated to simulate complex working conditions such as robot operation and human-machine interaction. Multiple combined loads are output simultaneously, and sensor output data under coupled conditions is collected.

[0023] After calibration, the control system processes the collected data using a built-in decoupling algorithm, removes coupling interference errors in each dimension, fits the input-output characteristic curves of the sensor in each dimension, accurately calculates core calibration parameters such as sensitivity, linearity, hysteresis error, repeatability error, and dimensional coupling error, and automatically generates a standardized calibration report with data traceability, thus completing the entire calibration process.

[0024] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A calibration device for a bionic petal-shaped elastomeric six-axis force sensor, characterized in that, It includes a rack module, a multi-dimensional precision loading module, a force value detection and feedback module, a sensor clamping and positioning module, and an intelligent control calibration module; The frame module provides fixed support for the overall device, which is used to support each functional module and ensure the overall structural stability during the calibration process; The sensor clamping and positioning module is fixed in the middle of the frame module and is used to adapt to the irregular structure of the bionic petal-shaped elastomer six-dimensional force sensor, so as to realize the stress-free and accurate positioning and fixing of the sensor and avoid the interference of clamping stress on the calibration results. The multidimensional precision loading module is arranged on the frame module and surrounds the sensor clamping and positioning module. It includes three sets of linear loading units and three sets of rotary loading units, which correspond to the six dimensions of three-dimensional force and three-dimensional torque respectively. Each loading unit is driven independently and works in concert to output precise single-dimensional force, single-dimensional torque or multi-dimensional coupled load to the sensor to be calibrated. The force detection and feedback modules are deployed for each loading unit and are used to collect the actual force, torque and displacement parameters of loading in each dimension in real time, and transmit the collected data to the intelligent control calibration module in real time. The intelligent control calibration module is electrically connected to the multidimensional precision loading module and the force value detection feedback module, respectively. It is used to control the loading sequence, loading amplitude and loading rate of each loading unit, receive feedback data and complete data parsing, error calculation and parameter fitting, so as to realize the automatic calibration of the six-dimensional force parameters of the sensor.

2. The calibration device for bionic petal-shaped elastomeric six-axis force sensor according to claim 1, characterized in that, The sensor clamping and positioning module includes a fixed base, an adaptive positioning bracket, a flexible buffer pad, and a locking and limiting component. The fixed base is detachably and fixedly connected to the frame module. The adaptive positioning bracket is adapted to the petal-shaped profile of the biomimetic petal-shaped elastomer sensor. A flexible buffer pad is laid inside the bracket to fit the sensor contact surface. The locking and limiting component adopts a multi-point uniform locking structure to achieve precise fixing of the sensor without squeezing or offset, and to eliminate residual stress during clamping.

3. The calibration device for bionic petal-shaped elastomeric six-axis force sensor according to claim 1, wherein, The three sets of linear loading units correspond to the linear force loading directions of the X, Y, and Z axes, respectively. Each set of linear loading units includes a precision servo electric cylinder, a linear displacement sensor, a force sensor, and a floating loading connector. The precision servo electric cylinder is fixed to the frame module, and its output end is connected to the floating loading connector. The floating loading connector makes flexible contact with the force-bearing end face of the sensor to be calibrated. The linear displacement sensor and the force sensor collect the loading displacement and loading force values ​​in real time to achieve precise closed-loop loading of linear force.

4. The calibration device for bionic petal-shaped elastomeric six-axis force sensor according to claim 1, wherein, The three sets of rotary loading units correspond to the X, Y, and Z axis torque loading directions, respectively. Each set of rotary loading units includes a precision servo rotary platform, an angle sensor, a torque detection component, and a rotary loading fixture. The precision servo rotary platform is fixed to the frame module, and the rotating end is connected to the rotary loading fixture. The angle sensor and torque detection component collect the rotation angle and loading torque value in real time to achieve precise quantitative loading of three-dimensional torque.

5. The calibration device for bionic petal-shaped elastomeric six-axis force sensor according to claim 1, wherein, The force detection feedback module includes a six-dimensional standard force detection component, a data acquisition card, and a signal filtering and amplification unit. The six-dimensional standard force detection component corresponds one-to-one with each loading unit and is used to acquire actual loading load data in each dimension with high precision. The signal filtering and amplification unit performs noise reduction and amplification processing on the acquired raw signal. The data acquisition card uploads the processed standard data to the intelligent control calibration module in real time.

6. The calibration apparatus for bionic petal-shaped elastomeric six-axis force sensor according to claim 1, wherein, The intelligent control calibration module has a built-in multi-dimensional decoupling calibration algorithm and automated calibration program, which can realize single-dimensional independent calibration, multi-dimensional coupled calibration, stepped loading calibration and cyclic loading calibration. It can fit the core calibration parameters of the sensor, such as six-dimensional force sensitivity, linearity, hysteresis error, repeatability error and inter-dimensional coupling error, based on the collected standard loading data and sensor output data, and automatically generate a calibration report.

7. The calibration device for a biomimetic petal-shaped elastomer six-dimensional force sensor according to claim 1, characterized in that, The frame module adopts an integrated cast rigid frame, and the frame surface has undergone aging stress relief treatment. The accuracy of the mounting reference surface of each module is not lower than IT6 level, which effectively reduces the calibration error caused by frame deformation during the calibration process.

8. A sensor calibration method based on the calibration device according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Equipment self-test: Start the calibration device and the intelligent control calibration module to perform a power-on self-test on each loading unit and detection module to confirm that each module is operating normally and that the data transmission is error-free. S2. Sensor clamping: Place the six-dimensional force sensor of the bionic petal-shaped elastomer to be calibrated in the sensor clamping and positioning module. The contour positioning is completed by the adaptive positioning card. The locking and limiting components are used to lock the sensor evenly to ensure that there is no residual stress or positional displacement. S3. Initial parameter calibration: The initial force, torque and displacement parameters in each dimension are cleared by the intelligent control calibration module to complete the zero-point calibration of the equipment. S4. Layered Calibration: Single-dimensional independent calibration and multi-dimensional coupled calibration are performed sequentially. During single-dimensional calibration, the corresponding dimension loading unit is started separately, and the load is loaded, maintained, and unloaded step by step according to the preset stepped load, and standard load data and sensor output data are collected. During multi-dimensional coupled calibration, multiple dimension loading units are started simultaneously to simulate complex stress scenarios and complete coupled loading calibration. S5. Data Decoupling and Parameter Calculation: The built-in decoupling algorithm eliminates loading coupling interference in various dimensions, fits the sensor input and output characteristic curves, and calculates various core calibration parameters. S6. Error Correction and Report Generation: Corrects sensor errors based on calibration parameters, automatically generates a standardized calibration report, and completes the calibration process.