Metrological calibration device and method for a tactile sensor

Abstract

The application provides a kind of metrological calibration device and method of tactile sensor, the device includes bearing platform, gantry frame, pressure loading mechanism, piston, oil cylinder and weight loading mechanism;Pressure loading mechanism includes the oil storage tank with oil storage cavity, the lower end of oil storage tank is provided with opening, and opening is closed by flexible film, and the first lifting mechanism is connected with gantry frame;The inner cavity of oil cylinder is communicated with oil storage cavity by oil pipe, and the standard load is loaded on piston by weight loading mechanism, to pressurize hydraulic oil in oil storage cavity, form standard pressure.By using flexible film as the component that is in contact with the calibrated tactile sensor array, the pressure transmission characteristics of hydraulic oil are utilized, when the hydraulic oil in the oil storage cavity is pressurized, the standard pressure is formed, the flexible film will be uniformly deformed as a whole, and the standard pressure is applied to the calibrated tactile sensor, thereby realizing the comprehensive and synchronous metrological calibration of all sensing units of the tactile sensor array.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tactile sensor calibration, in particular to a tactile sensor metrological calibration device and method. BACKGROUND

[0002] Tactile sensor is a sensor used in robots to simulate tactile function, and is a core component for realizing the tactile perception ability of dexterous hands. According to functions, it can be divided into contact sensor, force-torque sensor, pressure sensor and slip sensor, etc.

[0003] Most tactile sensors such as piezoresistive, piezoelectric, capacitive and electromagnetic can only sense normal force, and the main way to obtain pressure information is to integrate multiple sensing units into a tactile sensor array. Moreover, tactile sensors are constantly developing, and tactile sensors pursue higher sensitivity, higher integration, stronger extensibility and lower cost in performance.

[0004] In order to ensure the accuracy of tactile sensors, metrological calibration needs to be performed on tactile sensors. The existing sensor metrological calibration device, such as the multi-dimensional force loading and calibration device for tactile sensor disclosed in Chinese patent application No. 201410272708.2, comprises a positioning platform, a force loading unit and a vernier caliper. The vernier caliper comprises a horizontal vernier caliper and a vertical vernier caliper. The force loading unit comprises a stepping motor, a tension and compression force sensor, a rigid sleeve, a loading force contact, a table and a support. The force loading device is directly installed on the arc-shaped positioning frame of the positioning platform through the support, and can be rotated. By rotating the support, the rotation of the force loading device is realized, so that the force loading contact of the force loading device can give different angle forces to the sample on the slide.

[0005] In the above patent, the force loading device can only load and calibrate the local part of the tactile sensor array, and cannot realize the overall loading and overall calibration of the entire sensor array.

[0006] The existing technology also appears a sensor metrological calibration device capable of simulating the use environment of tactile sensor, such as the underwater tactile force sensor array calibration system providing temperature and pressure environment disclosed in Chinese patent application No. 201710428402.5, which comprises a pressure loading system, a temperature loading system, a tactile force sensor calibration system and an industrial computer. The sealed simulation pressure tank provides a water environment for temperature loading and pressure loading. The pressure loading system drives the pressure plug by a servo motor to pressurize the water in the sealed pressure tank, realizes different pressure environments for the underwater tactile force sensor, the temperature loading system is composed of water circulation and water temperature adjusting device, realizes the given different temperature values of the environment for the underwater tactile force sensor, the tactile force sensor calibration device is placed in the pressure tank, including array tactile force sensor fixing device and force generating device, can realize the calibration of force sensor array.

[0007] In the above patent, the pressure loading system pressurizes water to simulate the deep water environment used by the underwater tactile sensor, but the tactile force sensor calibration device still needs to be in contact with the tactile array sensor one by one to realize the force calibration experiment, and cannot realize the overall loading and overall calibration of the entire sensing array.

[0008] In summary, the current tactile sensor calibration device can only load and calibrate the local part of the tactile sensor array, and cannot realize the overall loading and overall calibration of the entire sensing array. SUMMARY

[0009] The technical problem to be solved by the present application is to provide a metrological calibration device and method for a tactile sensor, which can simultaneously calibrate the entire tactile sensing array.

[0010] The present application is implemented as follows:

[0011] In a first aspect, the present application provides a metrological calibration device for a tactile sensor, comprising: a bearing platform for fixing a calibrated tactile sensor, a gantry frame, a pressure loading mechanism, a piston, an oil cylinder and a weight loading mechanism;

[0012] The pressure loading mechanism comprises an oil storage tank, an oil storage cavity is formed in the inside of the oil storage tank, an opening is provided at the lower end of the oil storage tank, and the opening is closed by a flexible film, the gantry frame is fixed on the top of the bearing platform, the gantry frame is connected with a first lifting mechanism for driving the pressure loading mechanism to lift, and the first lifting mechanism is used to adjust the distance between the bearing platform and the flexible film to be equal to the thickness of the calibrated tactile sensor.

[0013] The inner cavity of the oil cylinder is communicated with the oil storage cavity through an oil pipe, the piston is slidingly connected with the oil cylinder, the standard load of the weight loading mechanism is loaded on the piston to pressurize the hydraulic oil in the oil storage cavity, form a standard pressure, and deform the flexible film downward to apply the standard pressure to the calibrated tactile sensor.

[0014] Further, the first lifting mechanism comprises a ball screw and a screw nut screw-connected with the ball screw, a flange is rigidly provided on the outer wall of the oil storage tank, the screw nut is fixedly connected with the flange, the upper and lower ends of the ball screw are rotatably connected with the gantry frame and the bearing platform respectively, the bearing platform is connected with a first servo motor, and the first servo motor is connected with the ball screw.

[0015] Further, the weight loading mechanism comprises a loading frame, a boom, a plurality of weights and a second lifting mechanism, the inner side of the loading frame is provided with a pressure head, the pressure head is above the piston, when loading, the pressure head is in contact with the piston, the boom is rigidly connected to the bottom of the loading frame, the second lifting mechanism is at the bottom of the boom and is used for lifting the boom, the plurality of weights are sleeved on the boom, and the weight loading mechanism further comprises a loading assembly for sequentially hanging the plurality of weights on the boom.

[0016] Further, the loading assembly comprises a support table, a plurality of support columns are rotationally connected to the support table, and the plurality of support columns are annularly arranged outside the boom with the axis of the boom as the center.

[0017] According to the number of the weights, each support column is uniformly and sequentially provided with through holes along the axis of the support column, and the through holes are spirally arranged along the axis of the support column, and a support rod for supporting the weights is inserted into the through hole.

[0018] Each support column is connected with a first sprocket, the first sprockets are jointly connected with a chain, a second servo motor is further arranged on the support table, the second servo motor is connected with a second sprocket, and the second sprocket is connected with the chain.

[0019] Further, the bottom of the pressure head is a spherical surface.

[0020] Further, the oil pressure instrument has five detection sensing ends, one of the detection sensing ends is used for detecting the hydraulic oil pressure in the inner cavity of the oil cylinder.

[0021] The remaining detection sensing ends are uniformly arranged at positions close to the flexible film at the lower end of the oil storage tank, are used for detecting whether the hydraulic oil pressure in the oil storage cavity and the hydraulic oil pressure in the inner cavity of the oil cylinder are consistent, and are further used for judging whether the pressure borne by the flexible film is uniform.

[0022] Further, the oil pipe is connected with an oil storage device at the middle section.

[0023] Further, the oil pipe is connected with an oil storage device at the middle section.

[0024] In a second aspect, the application provides a metrological calibration method of a tactile sensor, based on the metrological calibration device of the tactile sensor in the first aspect, the calibration method comprises the following steps:

[0025] S1, measuring the thickness of the calibrated tactile sensor, and controlling the first lifting mechanism to move until the distance between the bearing platform and the flexible film is equal to the thickness of the calibrated tactile sensor according to the thickness of the calibrated tactile sensor.

[0026] S2, the weight loading mechanism loads the piston, and the detection induction end detects the hydraulic oil pressure in the oil cylinder inner cavity and the oil storage cavity respectively; when the oil cylinder inner cavity and the oil storage cavity pressure are equal, and the pressure borne by the flexible film is uniform, the computer collects the output of the calibrated touch sensor at present, and compares it with the standard pressure in the oil storage cavity corresponding to the standard load applied by the weight loading mechanism, so as to realize the calibration of the calibrated touch sensor.

[0027] Further, in the step S2, according to the range of the calibrated touch sensor, the load point needing calibration is determined, the weight loading mechanism applies the standard load on the piston step by step, and each time a standard load is applied, the calibrated touch sensor is calibrated at the corresponding standard pressure point.

[0028] The advantage of the present application is that: by using a flexible film as a component in contact with the calibrated touch sensor array, the pressure transmission characteristics of hydraulic oil are used, when the hydraulic oil in the oil storage cavity is pressurized, the flexible film will deform uniformly as a whole, thereby forming a comprehensive and synchronous load on all sensing units of the calibrated touch sensor array. The problem of only being able to load and calibrate the local area of the touch sensor array in the prior art is solved, and the integrity and comprehensiveness of the calibration are improved.

[0029] By gradually applying the standard load to the piston through the weight loading mechanism, the standard pressure is stably transmitted to the flexible film through the hydraulic transmission mode, which can realize the precise pressure loading of the calibrated touch sensor from small to large in the range, so as to realize the wide range and high precision calibration, and ensure the accuracy and reliability of the touch sensor measurement. BRIEF DESCRIPTION OF DRAWINGS

[0030] The present application will be further described below with reference to the accompanying drawings and embodiments.

[0031] Figure 1 It is a schematic structural view of a touch sensor metrological calibration device in the present application.

[0032] Figure 2 It is a schematic structural view of a bearing platform, a gantry frame, a pressure loading mechanism and a laser interferometer connection structure in the present application.

[0033] Figure 3 It is a schematic structural view of a bearing platform, a gantry frame, a pressure loading mechanism and a laser interferometer connection structure in the present application. Figure 2 It is a partial enlarged view of A in the figure.

[0034] Figure 4 It is a partial enlarged view of B in the figure. Figure 2 It is a partial enlarged view of B in the figure.

[0035] Figure 5 It is a schematic structural view of a weight loading mechanism in the present application.

[0036] Figure 6 Structure diagram of four high-precision oil pressure sensors in the application arranged in an oil storage tank.

[0037] Figure 7 Structure diagram of a weight and a boom connection in the application.

[0038] Figure 8 Structure diagram of a loading assembly in the application.

[0039] Figure 9 Structure diagram of a first sprocket, a second sprocket and a chain connection in the application.

[0040] Figure 10 Structure diagram of a support column and a support rod connection in the application.

[0041] Figure 11 Structure diagram of a computer and a first drive, a second drive, a second lifting mechanism, a laser interferometer and an oil pressure instrument connection in the application.

[0042] Explanation of figure numbers:

[0043] 1, calibrated tactile sensor; 2, bearing platform; 3, gantry frame; 4, pressure loading mechanism; 41, oil storage tank; 411, oil storage cavity; 42, flexible film; 43, flange; 5, piston; 6, oil cylinder; 7, weight loading mechanism; 71, loading frame; 72, boom; 721, stop ring; 73, weight; 74, second lifting mechanism; 75, pressure head; 76, loading assembly; 761, support table; 762, support column; 763, support rod; 764, first sprocket; 765, chain; 766, second servo motor; 767, second sprocket; 8, first lifting mechanism; 81, ball screw; 82, screw nut; 83, first servo motor; 9, oil pipe; 10, oil pressure instrument; 101, high-precision oil pressure sensor; 11, laser interferometer; 111, laser light source; 112, fiber coupler; 113, measuring arm; 114, reference arm; 115, spectrometer; 12, oil storage device. DETAILED DESCRIPTION

[0044] Example one, please refer to Figures 1 to 11 The application provides a kind of metrological calibration device of tactile sensor, including: for fixed calibrated tactile sensor 1 bearing platform 2, gantry frame 3, pressure loading mechanism 4, piston 5, oil cylinder 6 and weight loading mechanism 7;

[0045] The pressure loading mechanism 4 comprises an oil tank 41, an oil storage cavity 411 is formed in the oil tank 41, the lower end of the oil tank 41 is provided with an opening, and the opening is sealed by a flexible film 42 made of flexible material such as silicone rubber. The thickness of the flexible film 42 is 1mm. The oil tank 41 is a thick-walled steel cylinder, that is, the top wall and the side wall of the oil tank 41 are thick steel plates, and the top wall and the side wall of the oil tank 41 do not deform when the standard load of the weight loading mechanism 7 is applied, and the oil storage cavity 411 is filled with hydraulic oil;

[0046] The gantry frame 3 is fixed on the top of the bearing platform 2, and the gantry frame 3 is connected with a first lifting mechanism 8 for driving the pressure loading mechanism 4 to lift, and the first lifting mechanism 8 is used to adjust the distance between the bearing platform 2 and the flexible film 42 to be equal to the thickness of the calibrated tactile sensor 1.

[0047] The inner cavity of the oil cylinder 6 is communicated with the oil storage cavity 411 through an oil pipe 9, the piston 5 is slidingly connected with the oil cylinder 6, the standard load of the weight loading mechanism 7 is loaded on the piston 5 to pressurize the hydraulic oil in the oil storage cavity 411, form a standard pressure, and deform the flexible film 42 downward, so that the standard pressure is applied to the calibrated tactile sensor 1 to realize the calibration of the calibrated tactile sensor 1.

[0048] Specifically, the first lifting mechanism 8 comprises a ball screw 81 and a screw nut 82 screw-connected with the ball screw 81, a flange 43 is rigidly arranged on the outer wall of the oil tank 41, the screw nut 82 is fixedly connected with the flange 43, the upper and lower ends of the ball screw 81 are rotatably connected with the gantry frame 3 and the bearing platform 2 respectively, the bearing platform 2 is connected with a first servo motor 83, and the first servo motor 83 is connected with the ball screw 81. The first servo motor 83 is connected with a first driver, and the first driver is connected with a computer.

[0049] Specifically, the weight loading mechanism 7 comprises a loading frame 71, a boom 72, a plurality of weights 73 and a second lifting mechanism 74, the second lifting mechanism 74 is a screw lifting machine, the inner side of the loading frame 71 is provided with a pressure head 75, the pressure head 75 is located above the piston 5, when loading, the pressure head 75 is in contact with the piston 5, the boom 72 is rigidly connected to the bottom of the loading frame 71, and the second lifting mechanism 74 is located at the bottom of the boom 72 and used to lift the boom 72. Before loading, the second lifting mechanism 74 is raised to separate the pressure head 75 from the piston 5, and during loading, the second lifting mechanism 74 is lowered to apply the standard load of the weight loading mechanism 7 to the pressure head 75.

[0050] A through hole is formed in the center of each weight 73, a plurality of weights 73 are sleeved on the suspender 72, the suspender 72 is arranged in the through hole, and the weight loading mechanism 7 further comprises a loading assembly 76 for sequentially hanging the plurality of weights 73 on the suspender 72. A retaining ring 721 is arranged on the outer wall of the suspender 72 to prevent the weight 73 from slipping off. When loading, the lowermost weight 73 is in contact with the retaining ring 721, and the standard pressure of the touch sensor 1 to be calibrated is loaded from small to large in the range by sequentially loading the weights 73.

[0051] Specifically, the loading assembly 76 comprises a support table 761, the second lifting mechanism 74 is installed on the support table 761, a plurality of support columns 762 are rotationally connected to the support table 761, and the plurality of support columns 762 are arranged in an annular array outside the suspender 72 with the axis of the suspender 72 as the center. The support column 762 is provided with three.

[0052] According to the number of weights 73, each support column 762 is uniformly spaced from top to bottom and is provided with a mounting hole, and the mounting hole is arranged in a spiral along the axis direction of the support column 762. A support rod 763 for supporting the weight 73 is inserted into the mounting hole.

[0053] Each support column 762 is connected with a first sprocket 764, the first sprockets 764 are jointly connected with a chain 765, and a second servo motor 766 is further arranged on the support table 761. The second servo motor 766 is connected with a second sprocket 767, and the second sprocket 767 is connected with the chain 765. The second servo motor 766 is connected with a second driver, and the second driver is connected with a computer. When the second servo motor 766 rotates, the three support columns 762 are synchronously rotated by the chain sprocket transmission mode.

[0054] If the number of weights 73 is 9, the number of support rods 763 is also 9, each support rod 763 corresponds to one weight 73, and from bottom to top, the included angle between the axes of two adjacent support rods 763 is An encoder for identifying the rotation angle of the support column 762 is further connected to the support column 762, and the encoder is connected with the computer. In the initial state, the lowermost support rod 763 is in contact with the lowermost weight 73, and is used to support all the weights 73 above the support rod 763. At this time, only the standard load of the loading frame 71, the suspender 72 and the pressure head 75 is applied to the piston 5, and the first stage loading is realized.

[0055] When the second standard load is loaded, the second lifting mechanism 74 is lifted, and the loading frame 71 and the boom 72 are lifted; then, the support column 762 is rotated by 36°. At this time, the lowermost weight 73 is separated from the lowermost support rod 763, and from bottom to top, the second support rod 763 is moved to below the second weight 73. After the second lifting mechanism 74 is lowered to the initial position, the second support rod 763 supports the second to ninth weights 73, and the first weight 73 is hung on the boom 72 through the retaining ring 721, so as to realize the loading of the second standard load.

[0056] In the manner of loading the second standard load, the weights 73 are cumulatively hung on the boom 72 one by one, so as to realize the step-by-step loading. After the support column 762 is rotated nine times (each time by 36°), all the support rods 763 are separated from the weights 73, so that the nine weights 73 are all hung on the ring.

[0057] When the nine weights 73 are all hung on the ring, after the support column 762 is rotated by 36° again, the lowermost weight 73 is in contact with the lowermost support rod 763, and the nine weights 73 are all supported by the lowermost support rod 763.

[0058] Specifically, the bottom of the pressure head 75 is a spherical surface. By arranging the spherical surface, the standard load applied by the weight loading mechanism 7 is more uniformly distributed on the piston 5.

[0059] Specifically, the oil pressure instrument 10 is further included, and the oil pressure instrument 10 has five detection sensing ends, and the detection sensing end is a high-precision oil pressure sensor 101. One of the detection sensing ends is used for detecting the hydraulic oil pressure in the inner cavity of the oil cylinder 6.

[0060] The remaining detection sensing ends are uniformly arranged at the position close to the flexible film 42 at the lower end of the oil storage tank 41, and are used for detecting whether the hydraulic oil pressure in the oil storage cavity 411 is consistent with the hydraulic oil pressure in the inner cavity of the oil cylinder 6. Through the output of the four detection sensing ends, it can be judged whether the pressure borne by the flexible film 42 is uniform. When the hydraulic oil pressure in the oil storage cavity 411 is consistent with the hydraulic oil pressure in the inner cavity of the oil cylinder 6, and the pressure borne by the flexible film 42 is uniform, the standard pressure in the oil storage cavity corresponding to the standard load applied by the weight loading mechanism 7 is the standard pressure borne by the calibrated tactile sensor 1. By comparing the output of the calibrated tactile sensor 1 collected by the computer at present, the calibration of the calibrated tactile sensor 1 is realized.

[0061] Specifically, the laser interferometer 11 is connected with the bearing platform 2, and is used for measuring the distance between the bearing platform 2 and the flexible film 42. The laser interferometer 11 is composed of a laser light source 111, a fiber coupler 112, a measuring arm 113, a reference arm 114 and a spectrometer 115. The measuring arm 113 is fixed vertically upward on the bearing platform 2, and the measuring arm 113, the reference arm 114 and the light source are all connected with the fiber coupler 112. The fiber coupler 112 is connected with the spectrometer 115, and the spectrometer 115 is connected with a computer. After the thickness of the tactile sensor is determined and input into the computer, the laser interferometer 11 confirms the distance between the flexible film 42 and the bearing platform 2. The computer controls the first driver, so that the first servo motor 83 is started to drive the ball screw 81 to rotate, and the oil tank 41 is moved downward. During the movement, the laser interferometer 11 continuously measures the distance between the bearing platform 2 and the flexible film 42, and feeds back to the computer to form a closed-loop control, until the distance between the bearing platform 2 and the flexible film 42 is equal to the thickness of the tactile sensor.

[0062] Specifically, the middle section of the oil pipe 9 is connected with an oil storage device 12. During the working process, the oil storage device 12 realizes real-time dynamic adjustment and supplement of the hydraulic oil.

[0063] Embodiment two, please refer to Figures 1 to 11 The present application provides a kind of metrological calibration method of tactile sensor, based on the metrological calibration device of tactile sensor described in embodiment one, the calibration method includes the following steps:

[0064] S1, the thickness of the calibrated tactile sensor 1 is measured, and according to the thickness of the calibrated tactile sensor 1, the first lifting mechanism 8 is controlled to move until the distance between the bearing platform 2 and the flexible film 42 is equal to the thickness of the calibrated tactile sensor 1;

[0065] In step S1, the thickness of the tactile sensor is measured by micrometer, and the measurement structure is input to the computer. The laser interferometer 11 measures the distance between the flexible film 42 and the bearing platform 2, and feeds back the measurement data to the computer. According to the thickness of the tactile sensor and the measurement data of the laser interferometer 11, the computer controls the first servo motor 83 to start through the first driver, so as to drive the ball screw 81 to rotate and move the oil tank 41 downward. During the movement, the laser interferometer 11 continuously measures the distance between the bearing platform 2 and the flexible film 42, and feeds back to the computer to form a closed-loop control, until the distance between the bearing platform 2 and the flexible film 42 is equal to the thickness of the tactile sensor. And the computer also records the zero point of the four high-precision oil pressure sensors 101 located at the oil tank 41.

[0066] S2, the weight loading mechanism 7 applies a standard load to the piston 5, and the detection inductive end detects the hydraulic oil pressure in the oil cylinder 6 inner cavity and the oil storage cavity 411 respectively; when the oil cylinder 6 inner cavity and the oil storage cavity 411 pressure are equal, and the pressure borne by the flexible film 42 is uniform, the computer collects the output of the calibrated touch sensor 1 at present, and compares it with the standard pressure in the oil storage cavity corresponding to the standard load applied by the weight loading mechanism 7, so as to realize the calibration of the calibrated touch sensor 1.

[0067] Specifically, in the step S2, according to the range of the calibrated touch sensor 1, the load point to be calibrated is determined, the weight loading mechanism 7 applies corresponding standard load on the piston 5 step by step, and the computer calibrates the corresponding standard pressure point of the calibrated touch sensor every time a standard load is applied.

[0068] Before the weight loading mechanism 7 is loaded, the second lifting mechanism 74 is lifted, the loading frame 71 and the boom 72 are moved upwards, the pressure head 75 is separated from the piston 5.

[0069] When loading, the second lifting mechanism 74 is retracted, the loading frame 71 and the boom 72 are moved downwards, so that the pressure head 75 is pressed on the piston 5, and the first level loading is realized. The oil cylinder pressure is: ;

[0070] The oil storage cavity pressure is: ;

[0071] In the formula,

[0072] The total weight of the loading frame 71, the boom 72 and the pressure head 75 is a known parameter, which can be measured by a weighing device;

[0073] The cross-sectional area of the oil cylinder 6 inner cavity is a known parameter;

[0074] According to the above formula, the standard pressure in the oil storage cavity corresponding to the standard load applied by the weight loading mechanism 7 can be calculated, that is, the standard pressure borne by the calibrated touch sensor 1.

[0075] After the weight loading mechanism 7 is loaded, five high-precision oil pressure sensors 101 collect the hydraulic oil pressure in the oil cylinder 6 and the oil storage cavity 411 respectively, and compare whether the two are consistent. Moreover, through the output of the four high-precision oil pressure sensors 101 connected to the lower part of the oil storage tank 41, the computer can judge whether the pressure borne by the flexible film 42 is uniform. When the hydraulic oil pressure in the oil storage cavity 411 and the hydraulic oil pressure in the oil cylinder 6 are consistent, and the pressure borne by the flexible film 42 is uniform, the standard pressure in the oil storage cavity corresponding to the standard load applied by the weight loading mechanism 7 is the standard pressure borne by the calibrated tactile sensor 1. The computer collects the output of the calibrated tactile sensor 1 at present and compares it with the pressure in the oil storage cavity corresponding to the standard load applied by the weight loading mechanism 7, so as to realize the calibration of the load point of the calibrated tactile sensor 1.

[0076] When the second standard load is loaded and calibrated, the second lifting mechanism 74 is lifted, so that the loading frame 71 and the boom 72 are lifted; then, the support column 762 is rotated by 36° (the rotation angle of the support column 762 can be measured by an encoder). At this time, the lowermost weight 73 is separated from the lowermost support rod 763, and from bottom to top, the second support rod 763 moves to the lower side of the second weight 73. After the second lifting mechanism 74 is lowered to the initial position, the second support rod 763 supports the second to ninth weights 73, so that the first weight 73 is hung on the boom 72 through the retaining ring 721, and the loading of the second load is realized.

[0077] At this time, the standard pressure applied to the calibrated tactile sensor 1 is: ;

[0078] The weight of the upper weight 73 hung on the boom 72; in the second load, The value of the weight of the first and second weights 73, and so on.

[0079] Similarly, when the hydraulic oil pressure in the oil cylinder 6 and the oil storage cavity 411 is consistent, and the pressure borne by the flexible film 42 is uniform, the computer collects the output of the calibrated tactile sensor 1 at present and compares it with the pressure in the oil storage cavity corresponding to the standard load applied by the weight loading mechanism 7, so as to realize the calibration of the load point of the calibrated tactile sensor 1.

[0080] In the manner of calibration of the second load, the weights 73 are hung on the boom 72 one by one in a cumulative manner, so as to realize the loading of the standard load in stages. After the support column 762 is rotated nine times (each time by 36°), all the support rods 763 are separated from the weights 73, so that the nine weights 73 are all hung on the lifting ring, and the precise pressure loading of the calibrated tactile sensor 1 from small to large in the range of the calibrated tactile sensor 1 is realized, so as to realize the calibration of a wide range and high precision.​

[0081] While the application has been described in terms of specific embodiments, it is to be understood that the embodiments described are merely illustrative of the present application and are not intended to be limiting. Changes and modifications can be suggested to those skilled in the art, and it is intended that the application encompass such changes and modifications as fall within the scope of the appended claims.

Claims

1. A metrological calibration device for a tactile sensor, characterized in that: The utility model relates to a kind of standard pressure loading mechanism for calibrating touch sensor, including: Carrying platform for fixing calibrated touch sensor, gantry frame, pressure loading mechanism, piston, oil cylinder and weight loading mechanism; The pressure loading mechanism includes oil tank, the inside of the oil tank forms an oil storage cavity, the lower end of the oil tank is provided with an opening, and the opening is closed by a flexible film, the gantry frame is fixed on the top of the carrying platform, the gantry frame is connected with the first lifting mechanism for driving the pressure loading mechanism to lift, the first lifting mechanism is used to adjust the distance between the carrying platform and the flexible film to be equal to the thickness of the calibrated touch sensor; The inner cavity of the oil cylinder is communicated with the oil storage cavity through an oil pipe, the piston is slidably connected with the oil cylinder, and the standard load of the weight loading mechanism is loaded on the piston to pressurize the hydraulic oil in the oil storage cavity, form a standard pressure, deform the flexible film downward, and apply the standard pressure to the calibrated touch sensor to realize the calibration of the calibrated touch sensor. The weight loading mechanism includes a loading frame, a hanger rod, a plurality of weights and a second lifting mechanism, the inner side of the loading frame is provided with a pressure head, the pressure head is located above the piston, and when loading, the pressure head is in contact with the piston, the hanger rod is rigidly connected to the bottom of the loading frame, the second lifting mechanism is located at the bottom of the hanger rod for lifting the hanger rod, a plurality of weights are sleeved on the hanger rod, and the weight loading mechanism further includes a loading assembly for hanging a plurality of weights on the hanger rod step by step. The loading assembly includes a support table, a plurality of support columns are rotatably connected to the support table, and the plurality of support columns are arranged in a ring shape outside the hanger rod with the axis of the hanger rod as the center. According to the number of weights, each support column is uniformly provided with a through hole from top to bottom, and the through holes are spirally arranged along the axis of the support column, and a support rod for supporting the weights is inserted into the through hole. Each support column is connected with a first sprocket, the first sprockets are jointly connected with a chain, and a second servo motor is further arranged on the support table, the second servo motor is connected with a second sprocket, and the second sprocket is connected with the chain.

2. A metrological calibration device for a tactile sensor as claimed in claim 1, characterized in that: The first lifting mechanism includes a ball screw and a screw nut spirally connected with the ball screw, the outer wall of the oil tank is rigidly provided with a flange, the screw nut is fixedly connected with the flange, and the upper and lower ends of the ball screw are rotatably connected with the gantry frame and the carrying platform respectively, the carrying platform is connected with a first servo motor, and the first servo motor is connected with the ball screw.

3. A metrological calibration device for a tactile sensor as claimed in claim 1, characterized in that: The bottom of the pressure head is a spherical surface.

4. A metrological calibration device for a tactile sensor as claimed in claim 1, characterized in that: Further including an oil pressure instrument, the oil pressure instrument has five detection sensing ends, one of which is used to detect the hydraulic pressure of the oil cylinder inner cavity; The remaining detection sensing ends are uniformly arranged at the position close to the flexible film at the lower end of the oil tank, which is used to detect whether the hydraulic oil pressure in the oil storage cavity and the hydraulic oil pressure in the oil cylinder inner cavity are consistent, and is also used to judge whether the pressure borne by the flexible film reaches uniformity.

5. A metrological calibration device for a tactile sensor as claimed in claim 1, characterized in that: A laser interferometer is further included and connected with the bearing platform for measuring the distance between the bearing platform and the flexible film.

6. A metrological calibration device for a tactile sensor as claimed in claim 1, characterized in that: The middle section of the oil pipe is connected with an oil reservoir.

7. A method of metrological calibration of a tactile sensor, characterized in that: The calibration method of the tactile sensor according to claim 4 comprises the following steps: S1, measuring the thickness of the tactile sensor to be calibrated, and controlling the first lifting mechanism to move until the distance between the bearing platform and the flexible film is equal to the thickness of the tactile sensor to be calibrated; S2, the weight loading mechanism applies a standard load to the piston, and the detection induction end detects the hydraulic oil pressure in the oil cylinder inner cavity and the oil storage cavity; when the pressures in the oil cylinder inner cavity and the oil storage cavity are equal and the pressure borne by the flexible film is uniform, the computer collects the output of the tactile sensor to be calibrated at present and compares it with the standard pressure in the oil storage cavity corresponding to the standard load applied by the weight loading mechanism, thereby realizing the calibration of the tactile sensor to be calibrated.

8. A metrological calibration method of a tactile sensor as claimed in claim 7, characterized in that: In step S2, according to the range of the tactile sensor to be calibrated, the load points to be calibrated are determined, the weight loading mechanism applies corresponding standard loads on the piston step by step, and the calibration of the tactile sensor to be calibrated is implemented for corresponding standard pressure points.

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