A six-dimensional force sensor based on Stewart structure

Abstract

This invention relates to the field of force sensor technology, and discloses a six-dimensional force sensor based on a Stewart structure, comprising a top plate, a middle plate, and a bottom plate coaxially arranged and stacked sequentially at intervals along the third direction; a first preload rod; four planar force-sensitive rods, each containing a planar force-sensitive core; a vertical force-sensitive rod, each containing a vertical force-sensitive core; four planar torque-sensitive rods, each containing a vertical force-sensitive core; and two vertical single-core sensitive rods, each containing a vertical single core. The planar force-sensitive core, vertical force-sensitive core, first torque-sensitive core, and vertical single core are all chip-type force-sensitive cores. The six-dimensional force sensor based on a Stewart structure disclosed in this invention achieves six-dimensional force detection using chip-type force-sensitive cores, fundamentally solving the problems of significant temperature drift, poor repeatability, and long-term creep inherent in strain gauge sensors. Furthermore, by improving the structure, it eliminates cross-interference between multi-dimensional signals.

Description

Technical Field

[0001] This invention relates to the field of force sensor technology, and in particular to a six-dimensional force sensor based on the Stewart structure. Background Technology

[0002] Steward structure sensors, a classic solution in the field of multidimensional force detection, achieve a certain degree of mechanical decoupling by distributing the load to each sensing rod and combining it with specific structural optimization. They possess advantages such as high stiffness, structural stability, strong load-bearing capacity, no error accumulation, and simple inverse kinematics. However, traditional Steward structure multidimensional force sensors typically employ strain gauge sensors to reduce frictional torque and avoid zero crossings. On the one hand, due to limitations in material properties and assembly, strain gauge sensors cannot completely eliminate the output influence of tensile stress and also suffer from significant temperature drift, poor repeatability, and long-term creep, resulting in limited measurement accuracy and long-term stability. On the other hand, the decoupling degree of traditional designs is limited, and the decoupling algorithm is highly complex, making it difficult to completely eliminate cross-interference between multidimensional signals. Summary of the Invention

[0003] Based on the above, the purpose of this invention is to provide a six-dimensional force sensor based on the Stewart structure, which realizes six-dimensional force detection by using a chip-type force-sensitive core. This not only fundamentally solves the problems of significant temperature drift, poor repeatability and long-term creep in strain gauge sensors, but also improves the structure, eliminating cross-interference between multi-dimensional signals, structural coupling and inherent defects of the detection method, and has higher detection accuracy, making it suitable for various harsh application scenarios.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A six-dimensional force sensor based on a Stewart structure, defining a first direction, a second direction, and a third direction that are mutually perpendicular, includes:

[0006] A top plate, a middle plate, and a bottom plate are coaxially arranged and stacked at intervals along the third direction. The top plate is connected to the middle plate and the bottom plate respectively. The top plate can move relative to the middle plate along a first direction and a second direction. A plane rectangular coordinate system is established on the upper surface of the middle plate with the center of the middle plate as the origin, forming a first quadrant, a second quadrant, a third quadrant, and a fourth quadrant.

[0007] A first pretension rod extends along the third direction and passes through the top plate and the bottom plate. The top plate can drive the middle plate to move relative to the bottom plate along the length direction of the first pretension rod.

[0008] Four planar force-sensitive rods are symmetrically distributed about the first axis of symmetry and the second axis of symmetry. One end of each planar force-sensitive rod is spherically connected to the top plate, and the other end is spherically connected to the middle plate. The projections of the four planar force-sensitive rods on the middle plate along the third direction extend radially along the middle plate and are respectively located in the first quadrant, the second quadrant, the third quadrant, and the fourth quadrant. Each planar force-sensitive rod is provided with a planar force-sensitive core.

[0009] A vertical force-sensitive rod, which contains a vertical force-sensitive core capable of detecting the third force in the third direction;

[0010] Four planar torque-sensitive rods are symmetrically distributed along a first axis of symmetry along the first direction and a second axis of symmetry along the second direction. One end of each planar torque-sensitive rod is spherically connected to the middle plate, and the other end is spherically connected to the base plate. Each planar torque-sensitive rod contains a first torque-sensitive core. The projections of the four planar torque-sensitive rods onto the middle plate along the third direction extend radially along the middle plate and are respectively located in the first quadrant, the second quadrant, the third quadrant, and the fourth quadrant. The first torque-sensitive core can detect the tangential force borne when compressed, and the four planar torque-sensitive rods can detect the first tangential force and the second tangential force generated when rotating around the first direction and the second direction.

[0011] Two vertical single-core sensitive rods, one end of each of the vertical single-core sensitive rods is spherically connected to the top plate, and the other end is spherically connected to the middle plate. Each vertical single-core sensitive rod contains a vertical single core, which can detect the force it bears when compressed. The two vertical single-core sensitive rods are symmetrically distributed about the first axis of symmetry or the second axis of symmetry, and their projections on the middle plate along the third direction extend along the second direction or the first direction. The two vertical single-core sensitive rods can detect the third tangential force generated when rotating around the third direction.

[0012] The planar force-sensitive core, the vertical force-sensitive core, the first torque-sensitive core, and the vertical single core are all chip-type force-sensitive cores.

[0013] As a preferred embodiment of a six-dimensional force sensor based on a Stewart structure, the vertical force sensing rod includes a first vertical force detection rod and a second vertical force detection rod, and the vertical force sensing core includes a first vertical force sensing sub-core and a second vertical force sensing sub-core. One end of the first vertical force detection rod is spherically connected to the top plate, and the other end is spherically connected to the top end of the first pre-tensioning rod. The first vertical force detection rod contains the first vertical force sensing sub-core, which is used to detect the third force acting upward in the third direction. One end of the second vertical force detection rod is spherically connected to the middle plate, and the other end is spherically connected to the base plate. The second vertical force detection rod contains the second vertical force sensing sub-core, which is used to detect the third force acting downward in the third direction.

[0014] As a preferred embodiment of a six-dimensional force sensor based on a Stewart structure, the planar force-sensitive rod, the planar torque-sensitive rod, the vertical single-core sensitive rod, the first vertical force detection rod, and the second vertical force detection rod are all force-sensitive rods. Each force-sensitive rod includes a first connecting rod and a second connecting rod. One of the first connecting rod and the second connecting rod is provided with a first mounting groove, and the other is provided with a first pressing block. The chip-type force-sensitive core is fixed to the bottom of the first mounting groove. At least a portion of the first pressing block extends into the first mounting groove and can move along the depth direction of the first mounting groove to squeeze or detach from the chip-type force-sensitive core.

[0015] As a preferred embodiment of a six-dimensional force sensor based on a Stewart structure, the six-dimensional force sensor based on a Stewart structure further includes:

[0016] Four first mounting bosses are provided on the top plate, and each first mounting boss is provided with a first ball socket;

[0017] Four second mounting protrusions are provided on the central plate, and each second mounting protrusion is provided with a second ball socket. The four second mounting protrusions correspond one-to-one with the four first mounting protrusions and the four planar force sensitive rods. One end of each planar force sensitive rod is a first ball and the other end is a second ball. The first ball is spherically connected in the first ball socket, and the second ball is spherically connected in the second ball socket.

[0018] Four third mounting bosses are provided on the central plate, and each of the third mounting bosses is provided with a third ball socket;

[0019] Four fourth mounting bosses are provided on the chassis, and each of the fourth mounting bosses is provided with a fourth ball socket. The four fourth mounting bosses correspond one-to-one with the four third mounting bosses and the four planar torque sensitive rods. One end of each planar torque sensitive rod is a third ball and the other end is a fourth ball. The third ball is spherically connected to the third ball socket, and the fourth ball is spherically connected to the fourth ball socket.

[0020] Two fifth mounting protrusions are provided on the top plate, and each fifth mounting protrusion is provided with a fifth ball socket;

[0021] Two sixth mounting protrusions are provided on the central plate, and each of the sixth mounting protrusions is provided with a sixth ball socket. The two sixth mounting protrusions correspond one-to-one with the two fifth mounting protrusions and the two vertical single-core sensitive rods. One end of each vertical single-core sensitive rod is a fifth ball and the other end is a sixth ball. The fifth ball is spherically connected to the fifth ball socket, and the sixth ball is spherically connected to the sixth ball socket.

[0022] As a preferred embodiment of a six-dimensional force sensor based on a Stewart structure, the first, second, third, fourth, fifth, and sixth spherical sockets are all spherical grooves, and the first, second, third, fourth, fifth, and sixth spheres are all spherical notches, with the notches and spherical grooves forming a spherical connection through point contact.

[0023] As a preferred embodiment of a six-dimensional force sensor based on a Stewart structure, the first mounting boss is provided with a first mounting slope, and the first mounting slope is provided with a first ball socket, the depth direction of the first ball socket being perpendicular to the first mounting slope. The second mounting boss is provided with a second mounting slope, and the second mounting slope is provided with a second ball socket, the depth direction of the second ball socket being perpendicular to the second mounting slope. The first mounting slope and the second mounting slope are arranged facing each other, with one of them facing the central axis of the disk and the other facing away from the central axis of the disk.

[0024] The third mounting boss is provided with a third mounting slope, and the third mounting slope is provided with a third ball socket. The depth direction of the third ball socket is perpendicular to the third mounting slope. The fourth mounting boss is provided with a fourth mounting slope, and the fourth mounting slope is provided with a fourth ball socket. The depth direction of the fourth ball socket is perpendicular to the fourth mounting slope. The third mounting slope and the fourth mounting slope are arranged opposite each other, with one of them facing the central axis of the middle plate and the other facing away from the central axis of the middle plate.

[0025] The fifth mounting boss is provided with a fifth mounting slope, and the fifth mounting slope is provided with a fifth ball socket. The depth direction of the fifth ball socket is perpendicular to the fifth mounting slope. The sixth mounting boss is provided with a sixth mounting slope, and the sixth mounting slope is provided with a sixth ball socket. The depth direction of the sixth ball socket is perpendicular to the sixth mounting slope. The fifth mounting slope and the sixth mounting slope are arranged opposite each other, with one of them facing the central axis of the middle plate and the other facing away from the central axis of the middle plate.

[0026] As a preferred embodiment of a six-dimensional force sensor based on a Stewart structure, the chip-type force-sensitive core includes a core base, a force-sensitive chip, and a force-sensitive membrane. The force-sensitive membrane is fixed on the core base, and the two together form a liquid cavity. The liquid cavity is filled with a hydraulic medium. The force-sensitive chip is fixed on the bottom wall of the liquid cavity. The force-sensitive chip can detect the force transmitted to the hydraulic medium through the force-sensitive membrane.

[0027] As a preferred embodiment of a six-dimensional force sensor based on a Stewart structure, the six-dimensional force sensor based on a Stewart structure further includes a first limiting block and a second limiting block. The top plate is provided with a first through hole, and the bottom plate is provided with a second through hole directly opposite the first through hole. One end of the first pretension rod extends out of the first through hole, and the other end of the first pretension rod extends out of the second through hole. The first limiting block is fixed to one end of the first pretension rod, and the second limiting block is fixed to the other end of the first pretension rod. The top plate can move a preset distance along the length direction of the first pretension rod.

[0028] As a preferred embodiment of a six-dimensional force sensor based on a Stewart structure, the six-dimensional force sensor based on a Stewart structure further includes a second preload rod, a third limiting block, and a fourth limiting block. The top plate is provided with a third through hole, and the middle plate is provided with a fourth through hole directly opposite the third through hole. One end of the second preload rod extends out of the third through hole. The third limiting block is fixed to one end of the second preload rod and abuts against the top plate. The other end of the second preload rod extends out of the fourth through hole. The fourth limiting block is fixed to the other end of the second preload rod and abuts against the middle plate. The diameter of the third through hole is larger than the diameter of one end of the second preload rod, and the diameter of the fourth through hole is larger than the diameter of the other end of the second preload rod.

[0029] As a preferred embodiment of a six-dimensional force sensor based on a Stewart structure, the six-dimensional force sensor based on a Stewart structure further includes a support rod, a seventh mounting boss, and an eighth mounting boss. The seventh mounting boss is disposed on the top plate, and the eighth mounting boss is disposed on the middle plate. One end of the support rod is spherically connected to the seventh mounting boss, and the other end is spherically connected to the eighth mounting boss. The projection of the support rod on the middle plate along the third direction extends along the first direction or the second direction.

[0030] The beneficial effects of this invention are as follows:

[0031] The six-dimensional force sensor based on the Stewart structure disclosed in this invention eliminates the tensile stress effects of assembly by abandoning existing strain gauge sensors. Since the planar force-sensitive core, vertical force-sensitive core, first torque-sensitive core, and vertical single core are all chip-type force-sensitive cores, this six-dimensional force sensor not only has advantages such as low temperature drift, high measurement repeatability, and strong creep resistance, but also excellent dynamic response characteristics, meeting the stringent application requirements of high-precision force control systems for rapid response, and is suitable for high-precision measurement fields. Furthermore, this six-dimensional force sensor is based on existing… The Stewart structure has been improved, which not only realizes the detection of the first force in the first direction, the second force in the second direction, and the third force in the third direction by the planar force-sensitive core and the vertical force-sensitive core, but also realizes the detection of the first tangential force around the first direction, the second tangential force around the second direction, and the third tangential force around the third direction by the first torque-sensitive core and the vertical single core. Since the lever arm in each direction is a constant value, the torque in each direction can be obtained separately, realizing the detection of the first torque, the second torque, and the third torque, and eliminating the cross-interference between multidimensional signals. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of a six-dimensional force sensor based on a Stewart structure provided in a specific embodiment of the present invention;

[0034] Figure 2 This is a main schematic diagram of a six-dimensional force sensor based on a Stewart structure, excluding the cylinder, provided in a specific embodiment of the present invention.

[0035] Figure 3This is a schematic diagram of the lower surface of the top plate of a six-dimensional force sensor based on a Stewart structure provided in a specific embodiment of the present invention;

[0036] Figure 4 This is a partial structural schematic diagram of a six-dimensional force sensor based on the Stewart structure provided in a specific embodiment of the present invention;

[0037] Figure 5 yes Figure 4 A diagram from another direction;

[0038] Figure 6 This is the first cross-sectional view of the six-dimensional force sensor based on the Stewart structure provided in a specific embodiment of the present invention;

[0039] Figure 7 This is the second cross-sectional view of the six-dimensional force sensor based on the Stewart structure provided in a specific embodiment of the present invention;

[0040] Figure 8 This is a cross-sectional view of the force-sensitive rod of a six-dimensional force sensor based on a Stewart structure provided in a specific embodiment of the present invention;

[0041] Figure 9 This is a cross-sectional view of the chip-type force-sensitive core of a six-dimensional force sensor based on the Stewart structure provided in a specific embodiment of the present invention;

[0042] Figure 10 This is a cross-sectional view of the vertical force-sensitive rod of a six-dimensional force sensor based on a Stewart structure, according to another embodiment of the present invention.

[0043] In the picture:

[0044] 11. Top plate; 111. First mounting boss; 1110. First socket; 1111. First mounting ramp; 112. Fifth mounting boss; 1121. Fifth mounting ramp; 1120. Fifth socket; 113. Seventh mounting boss; 1131. Seventh mounting ramp; 1130. Seventh socket; 12. Middle plate; 121. Second mounting boss; 1211. Second mounting ramp; 1210. Second socket; 122. Third mounting boss; 1221. Third mounting ramp; 1220. Third socket; 123. Sixth mounting boss; 1231. Sixth mounting ramp; 1230. Sixth socket; 124. Eighth mounting boss; 1241. Eighth mounting ramp; 1240. Eighth socket; 13. Base plate; 131. Fourth mounting boss; 1311. Fourth mounting ramp; 1310. Fourth socket;

[0045] 21. First preload rod; 22. First limit block; 23. Second limit block;

[0046] 301. First connecting rod; 302. Second connecting rod; 31. Planar force-sensitive rod; 311. First force-sensitive rod; 312. Second force-sensitive rod; 313. Third force-sensitive rod; 314. Fourth force-sensitive rod; 3201. First vertical rod; 3202. Second vertical rod; 3203. Third vertical rod; 3204. Vertical force-sensitive core; 321. First vertical force detection rod; 322. Second vertical force detection rod; 33. Planar torque-sensitive rod; 331. First torque-sensitive rod; 332. Second torque-sensitive rod; 333. Third torque-sensitive rod; 334. Fourth torque-sensitive rod; 34. Vertical single-core sensitive rod; 341. First single-core sensitive rod; 342. Second single-core sensitive rod;

[0047] 4. Chip-type force-sensitive core; 40. Liquid chamber; 401. Core base; 402. Force-sensitive chip; 403. Force-sensitive membrane; 41. First vertical force-sensitive sub-core; 42. Second vertical force-sensitive sub-core;

[0048] 51. Second preload rod; 52. Third limit block; 53. Fourth limit block;

[0049] 6. Support rod;

[0050] 7. Cylinder body. Detailed Implementation

[0051] To make the technical problems solved by the present invention, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "first position" and "second position" refer to two different positions.

[0053] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections or detachable connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; or internal connections between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0054] This embodiment provides a six-dimensional force sensor based on a Stewart structure, defining a first direction, a second direction, and a third direction that are perpendicular to each other, such as... Figures 1 to 9 As shown, the six-dimensional force sensor includes a top plate 11, a middle plate 12, and a bottom plate 13, which are coaxially arranged and stacked sequentially at intervals along a third direction. The top plate 11 is connected to the middle plate 12 and the bottom plate 13, respectively. The top plate 11 can move relative to the middle plate 12 along a first direction and a second direction. A planar rectangular coordinate system is established on the upper surface of the middle plate 12 with the center of the middle plate 12 as the origin, where the first direction is the X-axis and the second direction is the Y-axis, forming a first quadrant, a second quadrant, a third quadrant, and a fourth quadrant, as shown. Figure 5 As shown.

[0055] like Figures 1 to 9 As shown, the six-dimensional force sensor based on the Stewart structure also includes a first pre-tension rod 21, four planar force-sensitive rods 31, and a vertical force-sensitive rod. The first pre-tension rod 21 extends along a third direction and passes through the top plate 11 and the bottom plate 13. The top plate 11 can drive the middle plate 12 to move relative to the bottom plate 13 along the length direction of the first pre-tension rod 21. The four planar force-sensitive rods 31 are symmetrically distributed with a first axis of symmetry along a first direction and a second axis of symmetry along a second direction. One end of each planar force-sensitive rod 31 is spherically connected to the top plate 11, and the other end is spherically connected to the middle plate 12. The projections of the four planar force-sensitive rods 31 along the third direction on the middle plate 12 extend radially along the middle plate 12 and are located in the first quadrant, the second quadrant, the third quadrant, and the fourth quadrant, respectively. Each planar force-sensitive rod 31 is provided with a planar force-sensitive core. The vertical force-sensitive rod is provided with a vertical force-sensitive core 3204 that can detect the third force in the third direction.

[0056] like Figures 1 to 9As shown, the six-dimensional force sensor based on the Stewart structure also includes four planar torque sensing rods 33 and two vertical single-core sensing rods 34. The four planar torque sensing rods 33 are all located between the middle plate 12 and the base plate 13 and are symmetrically distributed about the first axis of symmetry and the second axis of symmetry. One end of each planar torque sensing rod 33 is spherically connected to the middle plate 12, and the other end is spherically connected to the base plate 13. Each planar torque sensing rod 33 has a first torque sensing core. The projections of the four planar torque sensing rods 33 along the third direction on the lower end surface of the middle plate 12 extend radially along the middle plate 12 and are located in the first quadrant, the second quadrant, the third quadrant, and the fourth quadrant, respectively. The first torque sensing core can detect the tangential force borne when compressed, and the four planar torque sensing rods 33 can detect the first tangential force and the second tangential force generated when rotating around the first direction and the second direction. Two vertical single-core sensitive rods 34 are located between the top plate 11 and the middle plate 12. One end of each vertical single-core sensitive rod 34 is spherically connected to the top plate 11, and the other end is spherically connected to the middle plate 12. Each vertical single-core sensitive rod 34 contains a vertical single core, which can detect the force exerted under pressure. The two vertical single-core sensitive rods 34 are symmetrically distributed about a second axis of symmetry, and the projections of the two vertical single-core sensitive rods 34 onto the middle plate 12 along a third direction extend along a first direction. The two vertical single-core sensitive rods 34 can detect the third tangential force generated when rotating about a third direction. In other embodiments, the two vertical single-core sensitive rods 34 can also be symmetrically distributed about a first axis of symmetry, and their projections onto the middle plate 12 along a third direction extend along a second direction, depending on actual needs.

[0057] In this embodiment, the top plate 11, middle plate 12, and bottom plate 13 are all circular disks, and the diameter of the middle plate 12 is smaller than the diameters of both the top plate 11 and the bottom plate 13. The upper surface of the top plate 11 is the force-bearing surface, and a corresponding force-bearing structure, such as an assembly thread (not shown in the figure), can be designed on the top plate 11 according to specific working conditions to receive the external force or torque to be measured. In other embodiments, the top plate 11, middle plate 12, and circular disks can also be quadrilateral, pentagonal, or other shapes, depending on actual needs.

[0058] like Figure 1 and Figure 2 As shown, in this embodiment, the first direction is the X-axis direction, the second direction is the Y-axis direction, the third direction is the Z-axis direction, and the first axis of symmetry is... Figure 5 The X-axis and the second axis of symmetry are in the figure. Figure 5 In the Y-axis, the planar force-sensitive core, vertical force-sensitive core, first torque-sensitive core, and vertical single core mentioned above are all chip-type force-sensitive cores 4. It should be noted that in other embodiments of the present invention, the first direction can also be the Y-axis direction, the second direction can be the X-axis direction, and the third direction can be the Z-axis direction, which can be set according to actual needs.

[0059] The six-dimensional force sensor based on the Stewart structure provided in this embodiment eliminates the tensile stress effects of assembly by abandoning existing strain gauge sensors. Since the planar force-sensitive core, vertical force-sensitive core, first torque-sensitive core, and vertical single core are all chip-type force-sensitive cores 4, this six-dimensional force sensor not only has the advantages of low temperature drift, high measurement repeatability, and strong creep resistance, but also excellent dynamic response characteristics, meeting the stringent application requirements of high-precision force control systems for rapid response, and is suitable for high-precision measurement fields. Furthermore, this six-dimensional force sensor is based on existing… Some Stewart structures have been improved to not only detect the first force in the first direction, the second force in the second direction, and the third force in the third direction by the planar force-sensitive core and the vertical force-sensitive core, but also to detect the first tangential force around the first direction, the second tangential force around the second direction, and the third tangential force around the third direction by the first torque-sensitive core and the vertical single core. Since the lever arm in each direction is a constant value, the torque in each direction can be obtained separately, realizing the detection of the first torque, the second torque, and the third torque, and eliminating cross-interference between multidimensional signals.

[0060] like Figure 1 As shown, the six-dimensional force sensor based on the Stewart structure in this embodiment also includes a cylinder 7. One end of the cylinder 7 is fixed to the chassis 13 and forms a mounting cavity with the chassis 13. The cylinder 7 serves to protect the internal force-sensitive rod. The middle plate 12 is located inside the mounting cavity, and the top plate 11 is located outside the cylinder 7 and spaced apart from the cylinder 7, so that when the six-dimensional force sensor detects forces or torques in different directions, the top plate 11 can move relative to the middle plate 12 or the chassis 13.

[0061] like Figure 7 As shown, the vertical force sensing rod in this embodiment includes two first vertical force sensing rods 321 and one second vertical force sensing rod 322. The vertical force sensing core 3204 includes a first vertical force sensing core 41 and a second vertical force sensing core 42. One end of each first vertical force sensing rod 321 is spherically connected to the top plate 11, and the other end is spherically connected to the top end of the first pre-tightening rod 21. Each first vertical force sensing rod 321 contains a first vertical force sensing core 41, which is used to detect a third force acting upward in the third direction. One end of the second vertical force sensing rod 322 is spherically connected to the center of the middle plate 12, and the other end is spherically connected to the center of the base plate 13. The second vertical force sensing rod 322 contains a second vertical force sensing core 42, which is used to detect a third force acting downward in the third direction.

[0062] In this embodiment, the planar force sensing rod 31, the planar torque sensing rod 33, the vertical single-core sensing rod 34, the first vertical force detection rod 321, and the second vertical force detection rod 322 are all as follows: Figure 8 The force-sensitive rod shown includes a first connecting rod 301 and a second connecting rod 302. One of the first connecting rod 301 and the second connecting rod 302 is provided with a first mounting groove, and the other is provided with a first pressing block. A chip-type force-sensitive core 4 is fixed to the bottom of the first mounting groove. At least part of the first pressing block extends into the first mounting groove and can move along the depth direction of the first mounting groove to squeeze or detach from the chip-type force-sensitive core 4.

[0063] In this embodiment, the two ends of the first connecting rod 301 and the second connecting rod 302 that are opposite to each other are as follows: Figure 8 The spherical structure shown has each sphere connected to a corresponding spherical socket. Each sphere is a spherical notch, with a diameter smaller than the diameter of the corresponding socket and a height smaller than the radius of the socket, ensuring a spherical connection between the notch and the socket. The spherical design at the end of the force-sensitive rod ensures that the force applied to it always passes through the center of the sphere and that the direction of the force is always along the central axis of the corresponding force-sensitive rod, enhancing the anti-eccentric load capability of the six-dimensional force sensor. It should be noted that in other embodiments of the invention, the force-sensitive rod is not limited to the cylindrical structure of this embodiment; it can also be a polygonal prism or other shapes, depending on actual needs.

[0064] like Figures 2 to 7 As shown, the six-dimensional force sensor based on the Stewart structure in this embodiment also includes four first mounting bosses 111, four second mounting bosses 121, four third mounting bosses 122, four fourth mounting bosses 131, two fifth mounting bosses 112, and two sixth mounting bosses 123. The first mounting bosses 111 and the second mounting bosses 121 are used to mount the planar force sensing rod 31, so that the planar force sensing rod 31 is spherically connected to the top plate 11 and the middle plate 12; the third mounting bosses 122 and the fourth mounting bosses 131 are used to mount the planar torque sensing rod 33, so that the planar torque sensing rod 33 is spherically mounted on the middle plate 12 and the base plate 13; the fifth mounting bosses 112 and the sixth mounting bosses 123 are used to mount the vertical single-core sensing rod 34, so that the vertical single-core sensing rod 34 is spherically mounted on the top plate 11 and the middle plate 12.

[0065] Specifically, such as Figures 2 to 7As shown, four first mounting bosses 111 are provided on the top plate 11, and each first mounting boss 111 is provided with a first ball socket 1110. Four second mounting bosses 121 are provided on the middle plate 12, and each second mounting boss 121 is provided with a second ball socket 1210. The four second mounting bosses 121 correspond one-to-one with the four first mounting bosses 111 and the four planar force sensitive rods 31. One end of each planar force sensitive rod 31 is a first ball, and the other end is a second ball. The first ball is spherically connected in the first ball socket 1110, and the second ball is spherically connected in the second ball socket 1210. Four third mounting bosses 122 are provided on the middle plate 12, and each third mounting boss 122 is provided with a third ball socket 1220. Four fourth mounting bosses 131 are provided on the chassis 13, and each fourth mounting boss 131 is provided with a fourth ball socket 1310. The four fourth mounting bosses 131 correspond one-to-one with the four third mounting bosses 122 and the four planar torque sensitive rods 33. One end of each planar torque sensitive rod 33 is a third ball, and the other end is a fourth ball. The third ball is spherically connected in the third ball socket 1220, and the fourth ball is spherically connected in the fourth ball socket 1310. Two fifth mounting protrusions 112 are provided on the top plate 11, and each fifth mounting protrusion 112 is provided with a fifth ball socket 1120. Two sixth mounting protrusions 123 are provided on the middle plate 12, and each sixth mounting protrusion 123 is provided with a sixth ball socket 1230. The two sixth mounting protrusions 123 correspond one-to-one with the two fifth mounting protrusions 112 and the two vertical single-core sensitive rods 34. One end of each vertical single-core sensitive rod 34 is a fifth ball, and the other end is a sixth ball. The fifth ball is spherically connected in the fifth ball socket 1120, and the sixth ball is spherically connected in the sixth ball socket 1230.

[0066] In this embodiment, the first socket 1110, the second socket 1210, the third socket 1220, the fourth socket 1310, the fifth socket 1120, and the sixth socket 1230 are all spherical grooves, and the first sphere, second sphere, third sphere, fourth sphere, fifth sphere, and sixth sphere are all spherical notches. The spherical notches and spherical grooves form a spherical connection through point contact, so that the force between them theoretically only exists through point contact. Compared with the traditional method of using strain gauge sensors for detection, this can significantly reduce the output error of the six-dimensional force sensor caused by non-detected forces, greatly reduce the crosstalk of the six-dimensional force sensor, and improve the detection accuracy. Furthermore, since the two are in point contact, it is convenient to decouple the algorithm later, which can reduce software costs and avoid accuracy errors caused by the algorithm. In this embodiment, the diameter of each spherical groove is larger than the diameter of the corresponding spherical notch. This design ensures that the contact between the spherical notch and the corresponding spherical groove is a point contact, avoiding the additional frictional force and frictional torque caused by the larger contact area, and increasing the detection accuracy of the six-dimensional force sensor.

[0067] In this embodiment, the mounting method between the top plate 11, the middle plate 12, and the base plate 13, combined with the point-contact spherical connection between the spherical groove and the spherical notch, allows the spherical notch at the end of each force-sensitive rod to rotate around the corresponding spherical groove by a certain angle. Once the force-sensitive rod is subjected to a non-axial force, the force-sensitive rod can rotate to avoid crosstalk output. This ensures that the six-dimensional force sensor is protected from damage by automatically changing the component force angle under high range, thereby improving the overload resistance of the six-dimensional force sensor.

[0068] like Figure 2 and Figures 4 to 7 As shown, the six-dimensional force sensor based on the Stewart structure in this embodiment also includes a support rod 6, a seventh mounting boss 113 and an eighth mounting boss 124. The seventh mounting boss 113 is disposed on the top plate 11, and the eighth mounting boss 124 is disposed on the middle plate 12. One end of the support rod 6 is spherically connected to the seventh mounting boss 113, and the other end is spherically connected to the eighth mounting boss 124. The projection of the support rod 6 on the middle plate 12 along a third direction extends along a first direction or a second direction. Specifically, the seventh mounting boss 113 is provided with a seventh mounting inclined surface 1131, and the seventh mounting inclined surface 1131 is provided with a seventh ball socket 1130. The depth direction of the seventh ball socket 1130 is perpendicular to the seventh mounting inclined surface 1131. The eighth mounting boss 124 is provided with an eighth mounting inclined surface 1241, and the eighth mounting inclined surface 1241 is provided with an eighth ball socket 1240. The depth direction of the eighth ball socket 1240 is perpendicular to the eighth mounting inclined surface 1241. The two ends of the support rod 6 are a seventh ball and an eighth ball, respectively. The seventh ball and the eighth ball are designed with spherical notches, so that the seventh ball and the eighth ball at both ends of the support rod 6 are spherically connected to the seventh ball socket 1130 and the eighth ball socket 1240, respectively.

[0069] In this embodiment, the two vertical single-core sensitive rods 34 are symmetrically distributed about the second axis of symmetry. The projection of the vertical single-core sensitive rod 34 onto the central plate 12 along the third direction extends along the first direction. The vertical single-core sensitive rod 34 can not only detect the third torque, but also output a signal when detecting the first force in the first direction. There are two support rods 6, which are also symmetrically distributed about the second axis of symmetry. The projection of the support rod 6 onto the central plate 12 along the third direction extends along the first direction. In this embodiment, the support rod 6 only serves as a single-sided counterweight to maintain the balance of the six-dimensional force sensor, thereby ensuring detection accuracy and preventing axial deviation. It should be noted that in other embodiments of the present invention, the support rod 6 can also be configured as a force-sensitive rod, and the chip-type force-sensitive core 4 of the force-sensitive rod can assist in detecting the applied force to improve the accuracy of the six-dimensional force sensor. In other embodiments, if the projections of the two support rods 6 and the two vertical single-core sensitive rods 34 along the third direction onto the central plate 12 extend along the second direction, the two support rods 6 are symmetrically distributed about the first axis of symmetry, and the two vertical single-core sensitive rods 34 are also symmetrically distributed about the first axis of symmetry. In this case, the vertical single-core sensitive rods 34 can output a signal when detecting the second applied force in the second direction.

[0070] like Figures 2 to 7 As shown, in this embodiment, the first mounting boss 111, the second mounting boss 121, the third mounting boss 122, the fourth mounting boss 131, the fifth mounting boss 112, the sixth mounting boss 123, the seventh mounting boss 113, and the eighth mounting boss 124 are all right-angled trapezoidal platforms. The projections of the first mounting boss 111, the fifth mounting boss 112, and the seventh mounting boss 113 onto the top plate 11 along a third direction are all rectangular, and the mounting ramps of these mounting bosses face the center of the top plate 11, while the vertical surfaces face away from the center of the top plate 11. The projections of the second mounting boss 121, the third mounting boss 122, the sixth mounting boss 123, and the eighth mounting boss 124 onto the middle plate 12 along a third direction are also rectangular, and the mounting ramps of these mounting bosses face away from the center of the middle plate 12, while the vertical surfaces face the center of the middle plate 12. The projection of the fourth mounting boss 131 onto the chassis 13 along a third direction is also rectangular, and the fourth mounting ramp 1311 of the fourth mounting boss 131 faces the center of the chassis 13, while the vertical surface faces away from the center of the chassis 13.

[0071] like Figures 2 to 7As shown, in this embodiment, the first mounting boss 111 is provided with a first mounting inclined surface 1111, and the first mounting inclined surface 1111 is provided with a first ball socket 1110. The depth direction of the first ball socket 1110 is perpendicular to the first mounting inclined surface 1111. The second mounting boss 121 is provided with a second mounting inclined surface 1211, and the second mounting inclined surface 1211 is provided with a second ball socket 1210. The depth direction of the second ball socket 1210 is perpendicular to the second mounting inclined surface 1211. The first mounting inclined surface 1111 and the second mounting inclined surface 1211 are arranged facing each other, and the first mounting inclined surface 1111 faces the central axis of the middle plate 12, while the second mounting inclined surface 1211 is away from the central axis of the middle plate 12. In this embodiment, the third mounting boss 122 is provided with a third mounting inclined surface 1221, and the third mounting inclined surface 1221 is provided with a third ball socket 1220. The depth direction of the third ball socket 1220 is perpendicular to the third mounting inclined surface 1221. The fourth mounting boss 131 is provided with a fourth mounting inclined surface 1311, and the fourth mounting inclined surface 1311 is provided with a fourth ball socket 1310. The depth direction of the fourth ball socket 1310 is perpendicular to the fourth mounting inclined surface 1311. The third mounting inclined surface 1221 and the fourth mounting inclined surface 1311 are arranged facing each other, and the fourth mounting inclined surface 1311 faces the central axis of the middle plate 12, while the third mounting inclined surface 1221 is away from the central axis of the middle plate 12. In this embodiment, the fifth mounting boss 112 is provided with a fifth mounting inclined surface 1121, and the fifth mounting inclined surface 1121 is provided with a fifth ball socket 1120. The depth direction of the fifth ball socket 1120 is perpendicular to the fifth mounting inclined surface 1121. The sixth mounting boss 123 is provided with a sixth mounting inclined surface 1231, and the sixth mounting inclined surface 1231 is provided with a sixth ball socket 1230. The depth direction of the sixth ball socket 1230 is perpendicular to the sixth mounting inclined surface 1231. The fifth mounting inclined surface 1121 and the sixth mounting inclined surface 1231 are arranged facing each other, with the fifth mounting inclined surface 1121 facing the central axis of the middle plate 12 and the sixth mounting inclined surface 1231 facing away from the central axis of the middle plate 12.

[0072] It should be noted that in other embodiments of the present invention, the first mounting slope 1111 may be away from the central axis of the middle plate 12, the second mounting slope 1211 may be facing the central axis of the middle plate 12; the fourth mounting slope 1311 may be away from the central axis of the middle plate 12, the third mounting slope 1221 may be facing the central axis of the middle plate 12; the fifth mounting slope 1121 may be away from the central axis of the middle plate 12, and the sixth mounting slope 1231 may be facing the central axis of the middle plate 12, depending on actual needs.

[0073] In this embodiment, the long side of the first mounting boss 111 forms an angle of 30° with the second direction, and the angle between the first mounting inclined surface 1111 and the top plate 11 is 45°. The long side of the second mounting boss 121 forms an angle of 30° with the second direction, and the angle between the second mounting inclined surface 1211 and the middle plate 12 is 45°. The long side of the third mounting boss 122 forms an angle of 60° with the second direction, and the angle between the third mounting inclined surface 1221 and the middle plate 12 is 45°. The long side of the fourth mounting boss 131 forms an angle of 60° with the second direction, and the angle between the fourth mounting inclined surface 1311 and the bottom plate 11 is 45°. The included angle between the disks 13 is 45°; the long side of the fifth mounting boss 112 extends along the first direction, and the included angle between the fifth mounting ramp 1121 and the top disk 11 is 45°; the long side of the sixth mounting boss 123 extends along the first direction, and the included angle between the sixth mounting ramp 1231 and the middle disk 12 is 45°; the long side of the seventh mounting boss 113 extends along the first direction, and the included angle between the seventh mounting ramp 1131 and the top disk 11 is 45°; the long side of the eighth mounting boss 124 extends along the first direction, and the included angle between the eighth mounting ramp 1241 and the middle disk 12 is 45°.

[0074] It should be noted that, in other embodiments of the present invention, the angles between the long side of the first mounting boss 111 and the long side of the second mounting boss 121 and the second direction are not limited to the above-mentioned 30°, but can also be 45°, 60° or other angle values. The angles between the first mounting inclined surface 1111 and the second mounting inclined surface 1211 and the top plate 11 and the middle plate 12 are also not limited to the above-mentioned 45°, but can also be 30°, 60° or other angle values, and are not limited here. The angles between the long side of the third mounting boss 122 and the fourth mounting boss 131 and the second direction are not limited to the above-mentioned 60°, but can also be 30°, 45° or other angle values. The angles between the third mounting inclined surface 1221 and the fourth mounting inclined surface 1311 and the top plate 11 and the middle plate 12 are also not limited to the above-mentioned 45°, but can also be 30°, 60° or other angle values, and are not limited here. The long sides of the fifth mounting boss 112 and the sixth mounting boss 123 are not limited to extending along the first direction as described above. They can also have an angle of 30°, 45°, 60° or other angle values ​​between their long sides and the second direction. The angles between the fifth mounting ramp 1121 and the sixth mounting ramp 1231 and the top plate 11 and the middle plate 12, respectively, are not limited to 45° as described above. They can also be 30°, 60° or other angle values, which are not limited here. The long sides of the seventh mounting boss 113 and the eighth mounting boss 124 are not limited to extending along the first direction as described above. They can also have an angle of 30°, 45°, 60° or other angle values ​​between their long sides and the second direction. The angles between the seventh mounting ramp 1131 and the eighth mounting ramp 1241 and the top plate 11 and the middle plate 12, respectively, are not limited to 45° as described above. They can also be 30°, 60° or other angle values, which are not limited here.

[0075] It should be noted that in other embodiments of the present invention, the first mounting boss 111 may not have a first mounting ramp 1111, the second mounting boss 121 may not have a second mounting ramp 1211, the third mounting boss 122 may not have a third mounting ramp 1221, the fourth mounting boss 131 may not have a fourth mounting ramp 1311, the fifth mounting boss 112 may not have a fifth mounting ramp 1121, and the sixth mounting boss 123 may not have a sixth mounting ramp 1231. Instead, the corresponding ball sockets may be machined on the corresponding mounting bosses, and each force-sensitive rod may be able to detect the force and tangential force in the corresponding direction.

[0076] like Figure 9 As shown, the chip-type force-sensitive core 4 of this embodiment includes a core base 401, a force-sensitive chip 402, and a force-sensitive membrane 403. The force-sensitive membrane 403 is fixed on the core base 401, and the two together form a liquid cavity 40. The liquid cavity 40 is filled with hydraulic medium. The force-sensitive chip 402 is fixed on the bottom wall of the liquid cavity 40. The force-sensitive chip 402 can detect the force transmitted to the hydraulic medium through the force-sensitive membrane 403. In this embodiment, the hydraulic medium is silicone oil. When the chip-type force-sensitive core 4 is pressurized, the force is transmitted to the force-sensitive chip 402 in sequence through the force-sensitive membrane 403 and the hydraulic medium. The force-sensitive chip 402 is sensitive to this pressure signal and then generates an electrical signal to output. Since pressure is a scalar quantity, the chip-type force-sensitive core 4 only outputs a signal when it is pressurized, thus avoiding the zero-crossing problem in principle.

[0077] like Figure 6 and Figure 7As shown, this embodiment of the six-dimensional force sensor based on the Stewart structure also includes a first limiting block 22 and a second limiting block 23. A first through hole is provided on the top plate 11, and a second through hole is provided on the bottom plate 13 directly opposite the first through hole. One end of the first pre-tensioning rod 21 extends out of the first through hole, and the other end of the first pre-tensioning rod 21 extends out of the second through hole. The first limiting block 22 is fixed to one end of the first pre-tensioning rod 21, and the second limiting block 23 is fixed to the other end of the first pre-tensioning rod 21. The top plate 11 can move a preset distance along the length of the first pre-tensioning rod 21. In this embodiment, there are two first pre-tensioning rods 21 and one first limiting block 22. The first limiting block 22 is fixed to the top of the two first pre-tensioning rods 21. The first vertical force detection rod 321 is spherically connected to the first limiting block 22. There are two second limiting blocks 23, which are respectively disposed at the lower ends of the two first pre-tensioning rods 21. The structural design of the first pretensioning rod 21, the first limiting block 22, and the second limiting block 23 enables the top plate 11 to move relative to the base plate 13 in a third direction, ultimately causing the top plate 11 to drive the middle plate 12 to move relative to the base plate 13 in a third direction. It should be noted that in other embodiments of the present invention, the number of first limiting blocks 22 can also be two, with each first limiting block 22 corresponding to one of the two first pretensioning rods 21. Each first limiting block 22 is fixed to the top of one of the first pretensioning rods 21, depending on actual needs.

[0078] like Figure 6 and Figure 7 As shown, the six-dimensional force sensor based on the Stewart structure in this embodiment also includes a second preload rod 51, a third limiting block 52, and a fourth limiting block 53. The top plate 11 is provided with a third through hole, and the middle plate 12 is provided with a fourth through hole directly opposite the third through hole. One end of the second preload rod 51 extends out of the third through hole. The third limiting block 52 is fixed to one end of the second preload rod 51 and abuts against the top plate 11. The other end of the second preload rod 51 extends out of the fourth through hole. The fourth limiting block 53 is fixed to the other end of the second preload rod 51 and abuts against the middle plate 12. The diameter of the third through hole is larger than the diameter of one end of the second preload rod 51, and the diameter of the fourth through hole is larger than the diameter of the other end of the second preload rod 51. In this embodiment, there are two second pretension rods 51, two third limiting blocks 52, and two fourth limiting blocks 53. The two third limiting blocks 52 are fixed to the top ends of the two second pretension rods 51, and the two fourth limiting blocks 53 are respectively disposed at the lower ends of the two second pretension rods 51. The structure of the second pretension rods 51, the third limiting blocks 52, and the fourth limiting blocks 53 ensures that the top plate 11 cannot move relative to the middle plate 12 in a third direction, and the top plate 11 can only move relative to the middle plate 12 in a first and / or second direction within a plane.

[0079] In this embodiment, the second pre-tightening rod 51 is installed between the top plate 11 and the middle plate 12, so that the top plate 11 and the middle plate 12 are pre-tightened. The diameter of the third through hole is larger than the diameter of one end of the second pre-tightening rod 51, and the diameter of the fourth through hole is larger than the diameter of the other end of the second pre-tightening rod 51. When the first force in the first direction, the second force in the second direction, or the third torque in the third direction is detected, the top plate 11 can move slightly to transmit the force or tangential force to be detected to the plane force sensitive rod 31 and the vertical single-core sensitive rod 34, so as to realize the detection of the first force, the second force, or the third torque.

[0080] The first preload rod 21, the first limit block 22, and the second limit block 23 enable the top plate 11 to drive the middle plate 12 to move relative to the chassis 13 in a third direction. The second preload rod 51, the third limit block 52, and the fourth limit block 53 prevent the top plate 11 from moving relative to the middle plate 12 in a third direction. When a first torque in the first direction, a second torque in the second direction, or a third force in the third direction exists, the planar force-sensitive rod 31 and the vertical single-core sensitive rod 34 will not detect these signals, reducing the difficulty of decoupling and accuracy loss. However, the planar torque-sensitive rod 33 and the vertical force-sensitive rod located between the middle plate 12 and the chassis 13 can detect these signals, enabling the detection of the first torque, the second torque, or the third force.

[0081] It should be noted that, in other embodiments of the present invention, the vertical force sensitive rod may also be... Figure 10 The dual-core detection rod shown is positioned between the top of the first pre-tensioning rod 21 and the top plate 11, or between the middle plate 12 and the bottom plate 13. The dual-core detection rod contains two vertical force-sensitive cores 3204. One vertical force-sensitive core 3204 is used to detect a third force acting upwards along a third direction, and the other vertical force-sensitive core 3204 is used to detect a third force acting downwards along a third direction. Specifically, as shown... Figure 10As shown, the dual-core detection rod includes a first vertical rod 3201, a second vertical rod 3202, and a third vertical rod 3203 arranged sequentially. A vertical force-sensitive core 3204 is disposed between the first vertical rod 3201 and the second vertical rod 3202 to detect a third force acting downward along the third direction, while another vertical force-sensitive core 3204 is disposed between the second vertical rod 3202 and the third vertical rod 3203 to detect a third force acting upward along the third direction. One end of the first vertical rod 3201 is a ninth sphere, and one end of the third vertical rod 3203 is a tenth sphere. When the dual-core detection rod is positioned between the middle plate 12 and the base plate 13, the middle plate 12 has a ninth socket, the depth direction of which is perpendicular to the lower end face of the middle plate 12. The base plate 13 has a tenth socket directly opposite the ninth socket, the depth direction of which is perpendicular to the upper end face of the base plate 13. The ninth sphere and the tenth sphere are spherically connected within the ninth socket, so that the dual-core detection rod is aligned with the lower end face of the middle plate 12 and the upper end face of the base plate 13. The end face is spherically connected; when the dual-core detection rod is set between the first limiting block 22 at the top of the first pre-tightening rod 21 and the top plate 11, the first limiting block 22 is provided with a ninth ball socket, and the top plate 11 is provided with a tenth ball socket directly opposite the ninth ball socket. The ninth ball is spherically connected in the ninth ball socket, and the tenth ball is spherically connected in the tenth ball socket, so that the dual-core detection rod is spherically connected to the lower end face of the first limiting block 22 at the top of the first pre-tightening rod 21 and the upper end face of the top plate 11.

[0082] Specifically, when a first force is applied in a first direction, a portion of the planar force-sensitive rod 31 and a portion of the vertical single-core sensitive rod 34 between the top plate 11 and the middle plate 12 are preferentially compressed, resulting in signal output, thus detecting the first force. When a second force is applied in a second direction, a portion of the planar force-sensitive rod 31 is compressed, resulting in signal output, thus detecting the second force. When a third force is applied in a third direction, one of the first vertical force detection rod 321 and the second vertical force detection rod 322 is compressed, resulting in signal output, thus detecting the third force.

[0083] When detecting the tangential force generated by rotation around the first or second direction, part of the planar torque sensing rod 33 is compressed, resulting in a signal output, thus realizing the detection of the tangential force in the corresponding direction. When detecting the tangential force generated by rotation around the third direction, the top plate 11 rotates along the third direction, and the first and second spheres of the planar force sensing rod 31 rotate within the first socket 1110 and the second socket 1210, respectively. The planar force sensing rod 31 is not compressed and there is no signal output, while the vertical single-core sensing rod 34 outputs a signal, realizing the detection of the tangential force in the third direction. The two vertical single-core sensing rods 34 can detect the tangential force in the clockwise and counterclockwise directions around the third direction, respectively, and thus obtain the corresponding torque.

[0084] Specifically, such as Figure 5 As shown, four planar force-sensitive rods 31 are defined as the first force-sensitive rod 311, the second force-sensitive rod 312, the third force-sensitive rod 313, and the fourth force-sensitive rod 314, respectively. Four planar torque-sensitive rods 33 are defined as the first torque-sensitive rod 331, the second torque-sensitive rod 332, the third torque-sensitive rod 333, and the fourth torque-sensitive rod 334, respectively. Two vertical single-core sensitive rods 34 are defined as the first single-core sensitive rod 341 and the second single-core sensitive rod 342, respectively. The state of each sensitive rod when detecting forces or torques in different directions is shown in the table below.

[0085]

[0086] As shown in the table above, when the top plate 11 is subjected to a first force in the positive X-axis direction, the second force-sensitive rod 312, the third force-sensitive rod 313, and the second single-core sensitive rod 342 are compressed, and the chip-type force-sensitive core 4 inside them outputs a signal; when the top plate 11 is subjected to a first force in the negative X-axis direction, the first force-sensitive rod 311, the fourth force-sensitive rod 314, and the first single-core sensitive rod 341 are compressed, and the chip-type force-sensitive core 4 inside them outputs a signal; when the top plate 11 is subjected to a second force in the positive Y-axis direction, the third force-sensitive rod 313 and the fourth force-sensitive rod 342... When rod 314 is compressed, its internal chip-type force-sensitive core 4 outputs a signal. When the top plate 11 is subjected to a second force in the negative Y-axis direction, the first force-sensitive rod 311 and the second force-sensitive rod 312 are compressed, and their internal chip-type force-sensitive cores 4 output a signal. When the top plate 11 is subjected to a third force in the positive Z-axis direction, the first vertical force detection rod 321 is compressed, and its internal chip-type force-sensitive core 4 outputs a signal. When the top plate 11 is subjected to a third force in the negative Z-axis direction, the second vertical force detection rod 322 is compressed, and its internal chip-type force-sensitive core 4 outputs a signal. Based on the force values ​​detected by the chip-type force-sensitive cores 4 of each force-sensitive rod, the corresponding first, second, and third forces can be calculated.

[0087] When a first tangential force is detected in the positive X-axis direction, the top plate 11 experiences the first tangential force in the positive X-axis direction, the third torque-sensitive rod 333 and the fourth torque-sensitive rod 334 are compressed, and the chip-type force-sensitive core 4 inside them outputs a signal; when a first tangential force is detected in the negative X-axis direction, the top plate 11 experiences the first tangential force in the negative X-axis direction, the first torque-sensitive rod 331 and the second torque-sensitive rod 332 are compressed, and the chip-type force-sensitive core 4 inside them outputs a signal; when a second tangential force is detected in the positive Y-axis direction, the top plate 11 experiences the second tangential force in the positive Y-axis direction, the first torque-sensitive rod 331 and the fourth torque-sensitive rod 334 are compressed, and the chip-type force-sensitive core 4 inside them outputs a signal. The force-sensitive core 4 outputs a signal. When a second tangential force is detected in the negative Y-axis direction, the top plate 11 experiences the second tangential force in the negative Y-axis direction, and the second torque-sensitive rod 332 and the third torque-sensitive rod 333 are compressed, causing the chip-type force-sensitive core 4 within them to output a signal. When a third tangential force is detected in the positive Z-axis direction, the top plate 11 experiences the third tangential force in the positive Z-axis direction, and the first single-core sensitive rod 341 is compressed, causing the chip-type force-sensitive core 4 within it to output a signal. When a third tangential force is detected in the negative Z-axis direction, the top plate 11 experiences the third tangential force in the negative Z-axis direction, and the second single-core sensitive rod 342 is compressed, causing the chip-type force-sensitive core 4 within it to output a signal. Based on the tangential force detected by the chip-type force-sensitive core 4 of each force-sensitive rod, the corresponding first torque, second torque, and third torque can be calculated.

[0088] The six-dimensional force sensor based on the Stewart structure in this embodiment is arranged in a double layer, which makes the arrangement of the planar force-sensitive rod 31, the vertical force-sensitive rod, the planar torque-sensitive rod 33, and the vertical single-core sensitive rod 34 more flexible and easier to decouple. This embodiment of the six-dimensional force sensor abandons the traditional strain gauge sensor and uses an oil-filled chip-type force-sensitive core 4 to achieve six-dimensional force detection, significantly improving detection accuracy. At the same time, the improved six-dimensional force sensor achieves physical isolation of inter-axis forces and torques, which not only reduces the production cost of the six-dimensional force sensor but also greatly reduces the difficulty and error value of back-end algorithm decoupling, further improving detection accuracy.

[0089] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A six-dimensional force sensor based on a Stewart structure, characterized in that, Define the first, second, and third directions that are perpendicular to each other, including: A top plate, a middle plate, and a bottom plate are coaxially arranged and stacked at intervals along the third direction. The top plate is connected to the middle plate and the bottom plate respectively. The top plate can move relative to the middle plate along a first direction and a second direction. A plane rectangular coordinate system is established on the upper surface of the middle plate with the center of the middle plate as the origin, forming a first quadrant, a second quadrant, a third quadrant, and a fourth quadrant. A first pretension rod extends along the third direction and passes through the top plate and the bottom plate. The top plate can drive the middle plate to move relative to the bottom plate along the length direction of the first pretension rod. Four planar force-sensitive rods are symmetrically distributed along a first axis of symmetry along the first direction and a second axis of symmetry along the second direction. One end of each planar force-sensitive rod is spherically connected to the top plate, and the other end is spherically connected to the middle plate. The projections of the four planar force-sensitive rods onto the middle plate along the third direction extend radially along the middle plate and are respectively located in the first quadrant, the second quadrant, the third quadrant, and the fourth quadrant. Each planar force-sensitive rod contains a planar force-sensitive core. A vertical force-sensitive rod, which contains a vertical force-sensitive core capable of detecting the third force in the third direction; Four planar torque-sensitive rods are symmetrically distributed about the first axis of symmetry and the second axis of symmetry. One end of each planar torque-sensitive rod is spherically connected to the middle plate, and the other end is spherically connected to the base plate. Each planar torque-sensitive rod contains a first torque-sensitive core. The projections of the four planar torque-sensitive rods onto the middle plate along the third direction extend radially along the middle plate and are respectively located in the first quadrant, the second quadrant, the third quadrant, and the fourth quadrant. The first torque-sensitive core can detect the tangential force borne when compressed, and the four planar torque-sensitive rods can detect the first tangential force and the second tangential force generated when rotating around the first direction and the second direction. Two vertical single-core sensitive rods, one end of each of the vertical single-core sensitive rods is spherically connected to the top plate, and the other end is spherically connected to the middle plate. Each vertical single-core sensitive rod contains a vertical single core, which can detect the force it bears when compressed. The two vertical single-core sensitive rods are symmetrically distributed about the first axis of symmetry or the second axis of symmetry, and their projections on the middle plate along the third direction extend along the second direction or the first direction. The two vertical single-core sensitive rods can detect the third tangential force generated when rotating around the third direction. The planar force-sensitive core, the vertical force-sensitive core, the first torque-sensitive core, and the vertical single core are all chip-type force-sensitive cores.

2. The six-dimensional force sensor based on the Stewart structure according to claim 1, characterized in that, The vertical force sensitive rod includes a first vertical force detection rod and a second vertical force detection rod. The vertical force sensitive core includes a first vertical force sensitive sub-core and a second vertical force sensitive sub-core. One end of the first vertical force detection rod is spherically connected to the top plate and the other end is spherically connected to the top end of the first pre-tensioning rod. The first vertical force detection rod contains the first vertical force sensitive sub-core, which is used to detect the third force acting upward in the third direction. One end of the second vertical force detection rod is spherically connected to the middle plate and the other end is spherically connected to the base plate. The second vertical force detection rod contains the second vertical force sensitive sub-core, which is used to detect the third force acting downward in the third direction.

3. The six-dimensional force sensor based on the Stewart structure according to claim 2, characterized in that, The planar force-sensitive rod, the planar torque-sensitive rod, the vertical single-core sensitive rod, the first vertical force detection rod, and the second vertical force detection rod are all force-sensitive rods. The force-sensitive rod includes a first connecting rod and a second connecting rod. One of the first connecting rod and the second connecting rod is provided with a first mounting groove, and the other is provided with a first pressing block. The chip-type force-sensitive core is fixed at the bottom of the first mounting groove. At least part of the first pressing block extends into the first mounting groove and can move along the depth direction of the first mounting groove to squeeze or detach from the chip-type force-sensitive core.

4. The six-dimensional force sensor based on the Stewart structure according to claim 1, characterized in that, The six-dimensional force sensor based on the Stewart structure also includes: Four first mounting bosses are provided on the top plate, and each first mounting boss is provided with a first ball socket; Four second mounting protrusions are provided on the central plate, and each second mounting protrusion is provided with a second ball socket. The four second mounting protrusions correspond one-to-one with the four first mounting protrusions and the four planar force sensitive rods. One end of each planar force sensitive rod is a first ball and the other end is a second ball. The first ball is spherically connected in the first ball socket, and the second ball is spherically connected in the second ball socket. Four third mounting bosses are provided on the central plate, and each of the third mounting bosses is provided with a third ball socket; Four fourth mounting bosses are provided on the chassis, and each of the fourth mounting bosses is provided with a fourth ball socket. The four fourth mounting bosses correspond one-to-one with the four third mounting bosses and the four planar torque sensitive rods. One end of each planar torque sensitive rod is a third ball and the other end is a fourth ball. The third ball is spherically connected to the third ball socket, and the fourth ball is spherically connected to the fourth ball socket. Two fifth mounting protrusions are provided on the top plate, and each fifth mounting protrusion is provided with a fifth ball socket; Two sixth mounting protrusions are provided on the central plate, and each of the sixth mounting protrusions is provided with a sixth ball socket. The two sixth mounting protrusions correspond one-to-one with the two fifth mounting protrusions and the two vertical single-core sensitive rods. One end of each vertical single-core sensitive rod is a fifth ball and the other end is a sixth ball. The fifth ball is spherically connected to the fifth ball socket, and the sixth ball is spherically connected to the sixth ball socket.

5. The six-dimensional force sensor based on the Stewart structure according to claim 4, characterized in that, The first, second, third, fourth, fifth, and sixth spherical sockets are all spherical grooves, and the first, second, third, fourth, fifth, and sixth spheres are all spherical notches. The spherical notches and the spherical grooves are connected in a spherical shape through point contact.

6. The six-dimensional force sensor based on the Stewart structure according to claim 4, characterized in that, The first mounting boss is provided with a first mounting slope, and the first mounting slope is provided with a first ball socket. The depth direction of the first ball socket is perpendicular to the first mounting slope. The second mounting boss is provided with a second mounting slope, and the second mounting slope is provided with a second ball socket. The depth direction of the second ball socket is perpendicular to the second mounting slope. The first mounting slope and the second mounting slope are arranged opposite each other, with one of them facing the central axis of the middle plate and the other facing away from the central axis of the middle plate. The third mounting boss is provided with a third mounting slope, and the third mounting slope is provided with a third ball socket. The depth direction of the third ball socket is perpendicular to the third mounting slope. The fourth mounting boss is provided with a fourth mounting slope, and the fourth mounting slope is provided with a fourth ball socket. The depth direction of the fourth ball socket is perpendicular to the fourth mounting slope. The third mounting slope and the fourth mounting slope are arranged opposite each other, with one of them facing the central axis of the middle plate and the other facing away from the central axis of the middle plate. The fifth mounting boss is provided with a fifth mounting slope, and the fifth mounting slope is provided with a fifth ball socket. The depth direction of the fifth ball socket is perpendicular to the fifth mounting slope. The sixth mounting boss is provided with a sixth mounting slope, and the sixth mounting slope is provided with a sixth ball socket. The depth direction of the sixth ball socket is perpendicular to the sixth mounting slope. The fifth mounting slope and the sixth mounting slope are arranged opposite each other, with one of them facing the central axis of the middle plate and the other facing away from the central axis of the middle plate.

7. The six-dimensional force sensor based on the Stewart structure according to claim 1, characterized in that, The chip-type force-sensitive core includes a core base, a force-sensitive chip, and a force-sensitive membrane. The force-sensitive membrane is fixed on the core base, and the two form a liquid cavity. The liquid cavity is filled with hydraulic medium. The force-sensitive chip is fixed on the bottom wall of the liquid cavity. The force-sensitive chip can detect the force transmitted to the hydraulic medium through the force-sensitive membrane.

8. The six-dimensional force sensor based on the Stewart structure according to claim 1, characterized in that, The six-dimensional force sensor based on the Stewart structure also includes a first limiting block and a second limiting block. The top plate is provided with a first through hole, and the bottom plate is provided with a second through hole facing the first through hole. One end of the first pretension rod extends out of the first through hole, and the other end of the first pretension rod extends out of the second through hole. The first limiting block is fixed to one end of the first pretension rod, and the second limiting block is fixed to the other end of the first pretension rod. The top plate can move a preset distance along the length direction of the first pretension rod.

9. The six-dimensional force sensor based on the Stewart structure according to claim 1, characterized in that, The six-dimensional force sensor based on the Stewart structure also includes a second preload rod, a third limiting block, and a fourth limiting block. The top plate has a third through hole, and the middle plate has a fourth through hole directly opposite the third through hole. One end of the second preload rod extends out of the third through hole. The third limiting block is fixed to one end of the second preload rod and abuts against the top plate. The other end of the second preload rod extends out of the fourth through hole. The fourth limiting block is fixed to the other end of the second preload rod and abuts against the middle plate. The diameter of the third through hole is larger than the diameter of one end of the second preload rod, and the diameter of the fourth through hole is larger than the diameter of the other end of the second preload rod.

10. The six-dimensional force sensor based on the Stewart structure according to claim 1, characterized in that, The six-dimensional force sensor based on the Stewart structure also includes a support rod, a seventh mounting boss, and an eighth mounting boss. The seventh mounting boss is disposed on the top plate, and the eighth mounting boss is disposed on the middle plate. One end of the support rod is spherically connected to the seventh mounting boss, and the other end is spherically connected to the eighth mounting boss. The projection of the support rod onto the middle plate along the third direction extends along the first direction or the second direction.

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