A decoupling method for three-dimensional force sensors based on multiple postures

Abstract

The present invention provides a decoupling device for a multi-posture three-dimensional force sensor, which includes an industrial robot, a laser tracker, a three-dimensional force sensor, a holding device, a hanging rope seat, a hanging rope rotating shaft, a hanging rope, a weight, and a reflecting target ball; the holding device is a flat plate support structure and is installed at one end of the robotic arm of the industrial robot; the three-dimensional force sensor is fixedly installed on the holding device through a positioning pin; the hanging rope seat is fixedly installed at the middle position of the three-dimensional force sensor through bolts; one end of the hanging rope rotating shaft is arranged in the middle of the hanging rope seat, and the other end is connected to the weight through the hanging rope; there are four reflecting target balls, which are fixedly installed at the four end positions of the holding device; the laser tracker is installed on one side of the industrial robot. At the same time, a method based on the device is also provided. This method does not require the use of a dedicated multi-dimensional force loading platform, reducing the cost of decoupling the three-dimensional force sensor; at the same time, it can ensure that the three-dimensional force sensor can be decoupled at the large component assembly site.

Description

Technical Field

[0001] The present invention belongs to the technical field of three-dimensional force sensor decoupling, and particularly relates to a calculation scheme for internal coupling parameters of a three-dimensional force sensor for large component digital assembly sites based on multiple postures, and further relates to a three-dimensional force sensor decoupling device and method based on multiple postures. Background Art

[0002] The output voltage value U of each channel of an ideal three-dimensional force sensor i only depends on the force F applied in this direction i and is independent of the forces in other directions. However, due to the influence of factors such as patch process, machining level, and transverse coefficient of strain gauges, the force applied to almost every direction of the sensor will affect the output signals in other directions of the sensor, which is the inter-dimensional coupling. Inter-dimensional coupling is an important factor affecting the measurement accuracy of three-dimensional force sensors. In order to improve the measurement accuracy of force, it is crucial to decouple the three-dimensional force sensor to eliminate inter-dimensional coupling.

[0003] Currently, decoupling a three-dimensional force sensor requires the use of a dedicated multi-dimensional force loading platform, and the accuracy of the forces loaded in each dimension of the three-dimensional force sensor will directly affect the decoupling accuracy of the three-dimensional force sensor. However, in large component digital assembly sites, multi-dimensional force loading conditions are often not available, and the accuracy of the loaded forces highly depends on the accuracy of the multi-dimensional force loading platform.

[0004] In order to be able to decouple a three-dimensional force sensor at large component digital assembly sites, while reducing the cost of three-dimensional force sensor decoupling as much as possible and improving the decoupling accuracy of three-dimensional force sensors, it has become an urgent problem to be solved. Summary of the Invention

[0005] Technical Solution: To solve the technical problems that the traditional three-dimensional force sensor decoupling method depends on a dedicated loading platform and has low decoupling accuracy, the present invention uses general equipment and instruments at large component digital assembly sites such as industrial robots and laser trackers to provide a three-dimensional force sensor decoupling device based on multiple postures, specifically including an industrial robot, a laser tracker, a three-dimensional force sensor, a holding device, a hanging rope seat, a hanging rope rotating shaft, a hanging rope, a weight, and a reflecting target ball; the holding device is a flat support structure and is installed at one end of the robotic arm of the industrial robot; the three-dimensional force sensor is fixedly installed on the holding device through a positioning pin; the hanging rope seat is fixedly installed at the middle position of the three-dimensional force sensor through bolts; one end of the hanging rope rotating shaft is set in the middle of the hanging rope seat, and the other end is connected to the weight through the hanging rope; there are four reflecting target balls, which are fixedly installed at the four end points of the holding device; the laser tracker is installed on one side of the industrial robot.

[0006] As an improvement, it further includes a first positioning pin and a second positioning pin, with two of each being independently provided. The first positioning pin fixedly installs the three-dimensional force sensor on the holding device, and the second positioning pin fixedly installs the lanyard seat on the three-dimensional force sensor.

[0007] Meanwhile, the present invention also provides a decoupling method for a three-dimensional force sensor based on multiple postures, which is a decoupling method based on the above-mentioned three-dimensional force sensor decoupling device based on multiple postures. The specific steps include

[0008] Step 1: First, use the holding device to connect the three-dimensional force sensor to the end of the industrial robot manipulator, hang a weight, and use a laser tracker to measure the posture of the three-dimensional force sensor relative to the horizontal coordinate system.

[0009] Step 2: According to the mass of the weight and the spatial posture of the three-dimensional force sensor, calculate the force components loaded on each dimension of the three-dimensional force sensor, and at the same time record the voltage values output by each dimension of the three-dimensional force sensor.

[0010] Step 3: First, drive the industrial robot to adjust the spatial pose of the three-dimensional force sensor; then use the laser tracker to measure the spatial posture of the three-dimensional force sensor; finally, calculate the force components loaded on each dimension of the three-dimensional force sensor, and record the voltage values output by each dimension of the three-dimensional force sensor at this time.

[0011] Step 4: Repeat Step 3 for n - 1 times. According to the magnitudes of the forces loaded on each dimension of the three-dimensional force sensor and the voltage values output by each dimension under n kinds of spatial postures, construct a decoupling parameter calculation model for the three-dimensional force sensor, and use the least squares method to calculate the coupling parameters of the three-dimensional force sensor, where n is an integer not less than 4.

[0012] As an improvement, the specific content in Step 1 includes the following:

[0013] ① Design a holding device for fixing the three-dimensional force sensor at the end of the robot. The holding device has four reflective target ball mounting holes, and the coordinates of the reflective target balls in the local coordinate system of the holding device after installation are and Use positioning pins to achieve the positioning of the three-dimensional force sensor and the holding device, and ensure that the local coordinate system of the holding device is parallel to the coordinate system of the three-dimensional force sensor.

[0014] ② Design a suspension mechanism for hanging the weight, so that when the posture of the three-dimensional force sensor is adjusted, the straight line where the weight lanyard is located can always intersect the Z-axis of the three-dimensional force sensor.

[0015] ③ Level the laser tracker and measure the coordinates of the four reflective target balls on the holding device in the horizontal coordinate system, which are respectively and

[0016] ④According to the coordinate system transformation principle, the coordinates of the reflection target ball in the local coordinate system of the holding device and the coordinates in the horizontal coordinate system satisfy the following relationship as shown in Equation 1:

[0017]

[0018] where \(i = \{1, 2, 3, 4\}\), is the attitude matrix of the holding device relative to the horizontal coordinate system, is the position vector of the holding device relative to the horizontal coordinate system, and the attitude matrix of the holding device relative to the horizontal coordinate system is calculated using the singular value decomposition method

[0019] As an improvement, the specific content in step two includes the following:

[0020] ①Suppose the mass of the loaded weight is \(m\) and the acceleration due to gravity is \(g\). Then the vector representation of the external force loaded on the three-dimensional force sensor (3) in the horizontal coordinate system \(O_s - xyz\) is According to the coordinate system transformation principle, the vector representation in the coordinate system \(O_g - xyz\) of the holding device is \(F\) g , as shown in Equation 2

[0021]

[0022] ②The coordinate system of the three-dimensional force sensor is parallel to the coordinate system \(O_g - xyz\) of the holding device. The vector of \(F\) s in the coordinate system of the three-dimensional force sensor is also represented as \(F\) g . Let \(F\) g = [F x , F y , F z T . Then \(F\) x , \(F\) y and \(F\) z are the force components loaded on the three dimensions of the three-dimensional force sensor;

[0023] ③Suppose the voltages output by the three dimensions of the three-dimensional force sensor during loading are \(U = [U x , U y , U z T .

[0024] As an improvement, the specific content in step three includes the following:

[0025] ①Drive the robot to adjust the spatial pose of the three-dimensional force sensor, measure the reflection target ball on the holding device using a laser tracker, and calculate the attitude matrix of the holding device relative to the horizontal coordinate system as ​​where j represents the j-th posture of the holding device;

[0026] ② Calculate the force components loaded on each dimension of the three-dimensional force sensor when the holding device is in the j-th posture as and where T represents the transpose of the matrix;

[0027] ③ Assume that when the holding device is in the j-th posture, the voltages output by each dimension of the three-dimensional force sensor are

[0028] As an improvement, for the coupling parameter calculation model of the three-dimensional force sensor in step four, the specific construction of the model includes the following content:

[0029] ① Adjust the spatial posture of the three-dimensional force sensor n - 1 times, plus the initial posture, to obtain n sets of force components of the three-dimensional sensor and the voltages U output by each dimension of the three-dimensional force sensor j ;

[0030] ② The force load input to the three-dimensional force sensor and the output voltage U j constitute a linear relationship, as shown in the following formula 3:

[0031]

[0032] where k lm is the coupling coefficient of the three-dimensional force sensor, l is an integer from 1 to 3, m is an integer from 1 to 3, and (d x , d y , d z ) is the zero drift of the three-dimensional force sensor;

[0033] ③ Let D = [d x , d y , d z T , then formula (3) can be written in the form of matrix multiplication as shown in formula 4:

[0034] U = K · F g + D (4)

[0035] Let [K, D] T = [X 1 , X 2 , X 3 , and [X 1 , X 2 , X 3 are the coupling parameters of the three-dimensional force sensor, and formula 5 is obtained

[0036]

[0037] When the holding device is in the j-th posture, the forces loaded on each dimension of the three-dimensional force sensor and the output voltage U j have the following relationship

[0038]

[0039] ④ Let be the three-dimensional force matrix loaded during decoupling; be the voltage vector in the X direction; be the voltage vector in the Y direction; be the voltage vector in the Z direction. Then, the decoupling parameter calculation model of the three-dimensional force sensor is expressed as Equation 7:

[0040]

[0041] Then, calculate the least squares solutions of X 1 , X 2 and X 3 as Equation 8 respectively

[0042]

[0043] and That is, they are used as the coupling parameters of the three-dimensional force sensor.

[0044] Advantageous effects: The device and method proposed by the present invention do not require the use of a dedicated multi-dimensional force loading platform, reducing the cost of decoupling the three-dimensional force sensor; at the same time, it can ensure that the three-dimensional force sensor can be decoupled at the assembly site of large components.

[0045] In addition, the present invention specifically uses a laser tracker to measure the posture of the three-dimensional force sensor relative to the horizontal coordinate system, then calculates the force component values loaded on each dimension of the three-dimensional force sensor, and finally calculates the coupling parameters of the three-dimensional force sensor by using the least squares method according to the force component values loaded on each dimension of multiple groups of three-dimensional force sensors and the output voltage values. The laser tracker used in this method has extremely high leveling accuracy, which can ensure the accuracy of the forces loaded on each dimension of the three-dimensional force sensor, thereby improving the decoupling accuracy of the sensor. Brief description of the drawings

[0046] Figure 1 is a schematic flow chart of a multi-posture-based three-dimensional force sensor decoupling method proposed by the present invention.

[0047] Figure 2 is a schematic diagram of the composition of a multi-posture-based three-dimensional force sensor decoupling system proposed by the present invention.

[0048] Figure 3 It is a schematic diagram of the cooperation between a three - dimensional force sensor and a holding device, as well as the suspension mechanism of a weight for the three - dimensional force sensor.

[0049] In the figure: 1 is an industrial robot, 2 is a reflective target ball, 3 is a three - dimensional force sensor, 4 is a holding device, 5 is a rope - hanging seat, 6 is a rope - hanging rotating shaft, 7 is a hanging rope, 8 is a weight, 9 is a laser tracker, 10 is a positioning pin 1, 11 is a rope - passing hole, 12 is a positioning pin 2, 13 is bolt 1, and 14 is bolt 2. Specific implementation mode

[0050] The technical solutions in the embodiments of the present invention will be clearly and completely described below, so that those skilled in the art can better understand the advantages and features of the present invention, and thus make a clearer definition of the protection scope of the present invention. The embodiments described in the present invention are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0051] Aiming at the problems that the traditional decoupling method of three - dimensional force sensors depends on a special loading platform and has low decoupling accuracy, the present invention uses general equipment and instruments on the digital assembly site of large components such as industrial robots and laser trackers to provide a decoupling method for three - dimensional force sensors, reducing the cost of decoupling three - dimensional force sensors and improving the decoupling accuracy of three - dimensional force sensors.

[0052] The main idea of the present invention is: using a laser tracker to measure the attitude of the three - dimensional force sensor relative to the horizontal coordinate system, then calculating the force component values loaded in each dimension of the three - dimensional force sensor, and finally calculating the coupling parameters of the three - dimensional force sensor by using the least - squares method based on the force component values loaded in each dimension of the three - dimensional force sensor and the output voltage values in multiple groups.

[0053] See Figure 2 and Figure 3 As shown in and, it is a decoupling device for a three - dimensional force sensor based on multiple postures, specifically including an industrial robot 1, a laser tracker 9, a three - dimensional force sensor 3, a holding device 4, a rope - hanging seat 5, a rope - hanging rotating shaft 6, a hanging rope 7, a weight 8, and a reflective target ball 2; the holding device 4 is a flat - plate support structure and is installed at one end of the robotic arm of the industrial robot 1; the three - dimensional force sensor 3 is fixedly installed on the holding device 4 through a positioning pin; the rope - hanging seat 5 is fixedly installed at the middle position of the three - dimensional force sensor 3 through a bolt; one end of the rope - hanging rotating shaft 6 is arranged in the middle of the rope - hanging seat 5, and the other end is connected to the weight 8 through the hanging rope 7; there are four reflective target balls 2, which are fixedly installed at the four end points of the holding device 4; the laser tracker 9 is installed on one side of the industrial robot 1.

[0054] It further includes two positioning pins 10 and two positioning pins 12, which are independently arranged. The positioning pin 10 fixedly mounts the three-dimensional force sensor 3 on the holding device 4, and the positioning pin 12 fixedly mounts the lanyard seat 5 on the three-dimensional force sensor 3.

[0055] It further includes two bolts 13 and two bolts 14, which are independently arranged. The bolt 13 fixedly mounts the three-dimensional force sensor 3 on the holding device 4, and the bolt 14 fixedly mounts the lanyard seat 5 on the three-dimensional force sensor 3.

[0056] The lanyard seat 5 is fixedly mounted on the three-dimensional force sensor 3.

[0057] The present invention also provides a decoupling method for the three-dimensional force sensor based on multiple postures of the above device, as Figures 1-3 shown, including the following steps:

[0058] Step 1: First, use the holding device 1 to connect the three-dimensional force sensor 3 to the end of the robot 1 and hang the weight 8, and the laser tracker 9 measures the posture of the three-dimensional force sensor 3 relative to the horizontal coordinate system. Specifically as follows:

[0059] ① Design a holding device 4 for fixing the three-dimensional force sensor 3 at the end of the robot 1. The three-dimensional force sensor 3 and the holding device 4 are positioned using the positioning pin 10 and fixed using the bolt 13 to ensure that the local coordinate system of the holding device 4 and the coordinate system of the three-dimensional force sensor 3 are parallel. Four reflecting target balls 2 are installed on the holding device 4, and the coordinates of the reflecting target balls in the local coordinate system of the holding device 4 are respectively and

[0060] ② Design a suspension mechanism for hanging the weight 8. The suspension mechanism consists of a lanyard seat 5 and a lanyard rotating shaft 6. The lanyard seat 5 and the three-dimensional force sensor 3 are positioned using the positioning pin 12 and fixed using the bolt 14, so that the central axis of the lanyard seat 5 coincides with the Z-axis of the three-dimensional force sensor 3. The lanyard rotating shaft 6 can rotate around the lanyard seat 5, and the lanyard rotating shaft 6 has a lanyard hole 11 through which the lanyard 7 for hanging the weight 8 can pass.

[0061] ③ Level the laser tracker 9 and measure the coordinates of the four reflecting target balls 2 on the holding device in the horizontal coordinate system Os-xyz, which are respectively and

[0062] ④ According to the coordinate transformation principle, the coordinates of the reflecting target ball 2 in the local coordinate system Og-xyz of the holding device 4 and the coordinates in the horizontal coordinate system Os-xyz satisfy the following relationship:

[0063]

[0064] where \(i = \{1, 2, 3, 4\}\), is the attitude matrix of the holding device relative to the horizontal coordinate system, is the position vector of the holding device relative to the horizontal coordinate system, and the attitude matrix of the holding device relative to the horizontal coordinate system \(O_s - xyz\) is calculated using the singular value decomposition method

[0065] Step 2: Calculate the force components loaded in each dimension of the three - dimensional force sensor 3 according to the mass \(m\) of the weight and the spatial attitude of the three - dimensional force sensor, and record the voltage values output by each dimension of the three - dimensional force sensor 3 at the same time. The specific steps are as follows:

[0066] ① Assume that the mass of the loaded weight is \(m\) and the acceleration due to gravity is \(g\). Then the vector of the external force loaded on the three - dimensional force sensor 3 in the horizontal coordinate system \(O_s - xyz\) can be expressed as According to the coordinate transformation principle, the vector in the holding device coordinate system \(O_g - xyz\) can be expressed as \(F\) g

[0067]

[0068] ② Since the three - dimensional force sensor coordinate system is parallel to the holding device coordinate system \(O_g - xyz\), then \(F\) s the vector in the three - dimensional force sensor coordinate system can also be expressed as \(F\) g . Let \(F\) g = \([F\) x , \(F\) y , \(F\) z \) T , then \(F\) x , \(F\) y and \(F\) z are the force components loaded in each dimension of the three - dimensional force sensor.

[0069] ③ Assume that the voltages output by each dimension of the three - dimensional force sensor during loading are \(U=\)[\(U\) x , \(U\) y , \(U\) z \) T .

[0070] Step 3: First, drive the robot 1 to adjust the spatial pose of the three - dimensional force sensor 3; then use the laser tracker 9 to measure the spatial attitude matrix of the three - dimensional force sensor; finally, calculate the force components loaded in each dimension of the three - dimensional force sensor and record the voltage values output by each dimension of the three - dimensional force sensor at this time. The specific steps are as follows:

[0071] ①Drive the robot 1, adjust the spatial pose of the three-dimensional force sensor 3, and use the laser tracker 9 to measure the reflection target ball 2 on the holding device 4. The attitude matrix of the holding device 4 relative to the horizontal coordinate system Os-xyz can be calculated as where j represents the holding device in the jth attitude.

[0072] ②When the holding device 4 is in the jth attitude, the force components loaded on each dimension of the three-dimensional force sensor 3 can be calculated as and where

[0073] ③Suppose when the holding device 4 is in the jth attitude, the voltages output by each dimension of the three-dimensional force sensor 3 are

[0074] Step 4: Repeat Step 3 for n - 1 times. According to the forces loaded on each dimension of the three-dimensional force sensor 3 and the voltages U j output by each dimension under each spatial pose, construct a coupling parameter calculation model for the three-dimensional force sensor, and use the least squares method to calculate the coupling parameters of the three-dimensional force sensor.

[0075] ①Adjust the spatial attitude of the three-dimensional force sensor 3 for n - 1 times. Adding the initial attitude, n sets of force components of the three-dimensional force sensor can be obtained and the voltages U j .

[0076] ②A large number of calibration experiments on three-dimensional force sensors show that the force load input to the three-dimensional force sensor 3 j and the output voltage U form a linear time-invariant system, that is, the output voltage of each output channel is the superposition of the forces loaded on the three dimensions of X, Y, and Z and the zero drift amount, as shown in formula (3).

[0077]

[0078] where k lm is the coupling coefficient of the three-dimensional force sensor 3, and (d x , d y , d z ) is the zero drift amount of the three-dimensional force sensor.

[0079] ③Let D = [d x , d y , d z T , then formula (3) can be written in the form of matrix multiplication.

[0080] U = K · F​g +D (4)

[0081] Therefore, there is [(F g ) T , 1][K, D] T = U T . Let [K, D] T = [X 1 , X 2 , X 3 , and [X 1 , X 2 , X 3 is the coupling parameter of the three - dimensional force sensor. Therefore, there is the following formula

[0082]

[0083] When the three - dimensional force sensor 4 is in the j - th posture, the forces loaded on each dimension of the three - dimensional force sensor 4 and the output voltage U j have the following relationship

[0084]

[0085] ④ Let Then the calculation model of the coupling parameter of the three - dimensional force sensor can be expressed as

[0086]

[0087] The least - squares solutions of X 1 , X 2 and X 3 can be calculated as

[0088]

[0089] and That is, they are used as the coupling parameters of the three - dimensional force sensor.

[0090] The above - described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. A three-dimensional force sensor decoupling method based on multiple postures, characterized in that: the decoupling method is performed based on a three-dimensional force sensor decoupling device based on multiple postures, the three-dimensional force sensor decoupling device based on multiple postures comprising an industrial robot (1), a laser tracker (9), a three-dimensional force sensor (3), a holding device (4), a hanging rope seat (5), a hanging rope shaft (6), a hanging rope (7), a weight (8), and a reflective target ball (2); the holding device (4) is a flat support structure, which is installed at one end of the mechanical arm of the industrial robot (1); the three-dimensional force sensor (3) is fixedly installed on the holding device (4) by a positioning pin; the hanging rope seat (5) is fixedly installed at the middle position of the three-dimensional force sensor (3) by a bolt; one end of the hanging rope shaft (6) is arranged in the middle of the hanging rope seat (5), and the other end is connected to the weight (8) by a hanging rope (7); four reflective target balls (2) are arranged and fixedly installed at the four end positions of the holding device (4); the laser tracker (9) is installed on one side of the industrial robot (1); Specific steps of the decoupling method include: Step 1: First, a three-dimensional force sensor (3) is connected to the end of the mechanical arm of the industrial robot (1) using a fixing device (4), and a weight (8) is hung, and a laser tracker (9) is used to measure the posture of the three-dimensional force sensor (3) relative to the horizontal coordinate system; Step 2: Calculate the force components of each dimension of the three-dimensional force sensor (3) based on the mass of the weight (8) and the spatial posture of the three-dimensional force sensor (3), and record the voltage values ​​output by each dimension of the three-dimensional force sensor; Step 3: First, the industrial robot (1) is driven to adjust the spatial posture of the three-dimensional force sensor (3); then the laser tracker (9) measures the spatial posture of the three-dimensional force sensor (3); finally, the component of the force applied to each dimension of the three-dimensional force sensor (3) is calculated, and the voltage value output by each dimension of the three-dimensional force sensor is recorded at the same time; Step 4: Repeat step 3 n-1 times, and build a coupling parameter solution model for the three-dimensional force sensor according to the magnitude of the force loaded in each dimension of the three-dimensional force sensor under n spatial postures and the voltage value output in each dimension, and use the least squares method to calculate the coupling parameters of the three-dimensional force sensor, where n is an integer not less than 4.

2. According to the multi-posture based three-dimensional force sensor decoupling method of claim 1, it is characterized in that: the multi-posture based three-dimensional force sensor decoupling device also includes a positioning pin one (10) and a positioning pin two (12), each of which is independently provided with two, wherein the positioning pin one (10) fixes the three-dimensional force sensor (3) on the holding device (4), and the positioning pin two (12) fixes the hanging rope seat (5) on the three-dimensional force sensor (3).

3. The method for decoupling a three-dimensional force sensor based on multi-posture according to claim 1 is characterized in that: step 1 specifically includes the following contents: ①A holding device designed to fix a three-dimensional force sensor at the end of a robot. The holding device has four mounting holes for reflecting target balls, and the coordinates of the reflecting target balls in the local coordinate system of the holding device after installation are and Use a positioning pin to position the three-dimensional force sensor and the holding device to ensure that the local coordinate system of the holding device is parallel to the coordinate system of the three-dimensional force sensor; ② Design a suspension mechanism for hanging weights so that when the three-dimensional force sensor is adjusted, the straight line where the weight hanging rope is located can always intersect with the Z axis of the three-dimensional force sensor; ③Level the laser tracker and measure the coordinates of the four reflecting target balls on the holding device in the horizontal coordinate system, which are respectively and ④According to the coordinate system transformation principle, the coordinates of the reflection target ball in the local coordinate system of the holding device and the coordinates in the horizontal coordinate system satisfy the following relationship as shown in Equation 1: where i = {1, 2, 3, 4}, is the attitude matrix of the holding device relative to the horizontal coordinate system, is the position vector of the holding device relative to the horizontal coordinate system, and the attitude matrix of the holding device relative to the horizontal coordinate system is calculated by the singular value decomposition method 4. The three-dimensional force sensor decoupling method based on multiple postures according to claim 1, characterized in that: the following specific contents are included in step two: ① Let the mass of the loaded weight be m and the acceleration due to gravity be g. Then, the vector representation of the external force applied to the three-dimensional force sensor (3) in the horizontal coordinate system Os-xyz is According to the coordinate system transformation principle, The vector representation in the holding device coordinate system Og-xyz is F g , as shown in Equation 2 ② The coordinate system of the three-dimensional force sensor is parallel to the coordinate system Og-xyz of the holding device, and F is obtained s The vector in the three-dimensional force sensor coordinate system is also represented as F g , let F g = [F x , F y , F z T , then F x , F y and F z are the force components loaded in the three dimensions of the three-dimensional force sensor;​ ③Let the voltages output by the three-dimensional force sensor in three dimensions during loading be U = [U x , U y , U z T .​ 5. The three-dimensional force sensor decoupling method based on multiple postures according to claim 1, characterized in that: the following specific contents are included in step three: ①Drive the robot, adjust the spatial pose of the three-dimensional force sensor, measure the reflection target ball on the holding device using a laser tracker, and calculate that the attitude matrix of the holding device relative to the horizontal coordinate system is where j represents that the holding device is in the j-th attitude; ② Calculate the force components loaded on each dimension of the three-dimensional force sensor when the holding device is in the j-th posture as and where T represents the transpose of the matrix; ③Assume that when the holding device is in the j-th posture, the voltages output by each dimension of the three-dimensional force sensor are 6. The three-dimensional force sensor coupling parameter calculation model in step four of the three-dimensional force sensor decoupling method based on multiple postures according to claim 1, characterized in that: the specific contents of constructing the model are as follows: ①Adjust the spatial attitude of the three-dimensional force sensor n - 1 times, and together with the initial attitude, obtain n sets of force components of the three-dimensional sensor and the voltage U output by each dimension of the three-dimensional force sensor j ; ② The force load input by the three-dimensional force sensor and the output voltage U j form a linear relationship, as shown in the following formula 3 specifically: where k lm is the coupling coefficient of the three-dimensional force sensor, l is an integer from 1 to 3, m is an integer from 1 to 3, (d x , d y , d z ) is the zero drift of the three-dimensional force sensor; ③Let D = [d x , d y , d z T , then formula (3) can be written in the form of matrix multiplication, as shown in formula 4:​ U = K·F g + D (Equation 4) Let [K,D] T = [X 1 , X 2 , X 3 , [X 1 , X 2 , X 3 be the formula for obtaining the coupling parameters of the three-dimensional force sensor 5 When the holding device is in the j-th posture, the forces applied to each dimension of the three-dimensional force sensor and the output voltage U j have the following relationship ④Let be the three-dimensional force matrix loaded during decoupling; be the voltage vector in the X direction; be the voltage vector in the Y direction; be the voltage vector in the Z direction. Then, the decoupling parameter calculation model of the three-dimensional force sensor is expressed by Equation 7: Then, calculate X 1 , X 2 and X 3 The least-squares solutions of are Formula 8 respectively and i.e., as the coupling parameter of the three-dimensional force sensor.

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