A tensile test fixture and method for robotic tendons

Abstract

This application discloses a tensile testing fixture and method for robot tendons. The fixture includes a housing, a mounting interface, a clamping assembly, and a driving mechanism. The mounting interface is connected to the housing. The clamping assembly includes a fixed clamping block and a movable clamping block arranged opposite to each other along a first direction. The fixed clamping block is fixedly mounted on the housing. The driving mechanism is mounted on the housing and its output end is connected to the movable clamping block. The movable clamping block can move along the first direction under the action of the driving mechanism to approach or move away from the fixed clamping block. The fixed clamping block has a first clamping surface facing the movable clamping block. The first clamping surface has a first protrusion and a first recess. Both the first protrusion and the first recess are constructed in an arc shape and are alternately arranged. The movable clamping block has a second clamping surface facing the fixed clamping block. The second clamping surface has a second protrusion and a second recess. Both the second protrusion and the second recess are constructed in an arc shape and are alternately arranged.

Description

Technical Field

[0001] This application relates to the field of performance testing technology for robot transmission components, and in particular to a tensile testing fixture for robot tendons. Background Technology

[0002] In robotic chord drive systems, the chords must withstand cyclic tensile loads, and their tensile strength directly determines the robot's load capacity and service life. Currently, mainstream chord materials include ultra-high molecular weight polyethylene (UPE), PBO fiber, and tungsten wire rope. However, when using a universal testing machine to perform tensile tests on these materials, existing fixtures generally suffer from the following technical defects: First, slippage is a prominent issue: UPE and PBO fibers have smooth surfaces and extremely low coefficients of friction (usually below 0.1), while tungsten wire ropes are hard but brittle; traditional flat or wedge-shaped clamps cannot provide sufficient static friction, and the tendon ropes are very prone to slipping relative to the clamping surface during testing, resulting in a significantly lower measured peak force. Test data shows that the maximum tensile force error can reach more than 30%, which cannot reflect the true fracture strength of the material.

[0003] Secondly, the clamping damage is severe: in order to suppress slippage, operators are often forced to clamp too tightly, which can easily cause the UPE / PBO fibers to be crushed and stress concentration to occur, or cause microcracks to appear on the surface of the tungsten wire rope; premature breakage of such clamping parts will render a large amount of test data invalid and significantly increase the test cost.

[0004] Furthermore, the existing clamps have poor versatility: they are difficult to use to accommodate the clamping requirements of high-strength fine filaments (such as tungsten wire rope with a diameter of 0.6 mm and a breaking strength of about 530 N) and high-modulus coarse filaments (such as PBO fiber with a diameter of 0.8 mm and a breaking strength of about 1136 N) as well as soft, thick-diameter UPE ropes. Changing clamps is time-consuming and laborious, and it is difficult to guarantee a stable clamping effect on ropes with different diameters and surface properties.

[0005] In view of this, a new technical solution is needed to at least solve one of the above-mentioned technical problems. Summary of the Invention

[0006] The technical problem to be solved by this application is to overcome the defects in the prior art and thus provide a tensile testing fixture for robot tendons.

[0007] To achieve the above objectives, this application adopts the following technical solution: According to a first aspect of this application, a tensile testing fixture for robotic tendons is provided, the testing fixture comprising: case; The mounting interface is connected to the housing and is located at the end of the housing; A clamping assembly configured to clamp a robot tendon cable to be tested; the clamping assembly includes a fixed clamping block and a movable clamping block disposed opposite to each other along a first direction, the fixed clamping block being fixedly disposed on the housing; A drive mechanism is mounted on the housing. The output end of the drive mechanism is connected to the movable clamping block. The movable clamping block can move in a first direction under the driving force of the drive mechanism to move closer to or further away from the fixed clamping block. The fixed clamping block has a first clamping surface facing the movable clamping block. The first clamping surface has at least two first protrusions and at least two first recesses. The first protrusions and first recesses are both constructed in an arc shape and are alternately arranged. The movable clamping block has a second clamping surface facing the fixed clamping block. The second clamping surface has at least two second protrusions and at least two second recesses. Both the second protrusions and the second recesses are constructed in an arc shape and are alternately arranged.

[0008] Optionally, the first protrusion is matched and docked with the second recess, and the second protrusion is matched and docked with the first recess.

[0009] Optionally, the first protrusion and the first recess have a first height difference, and the second protrusion and the second recess have a second height difference, both of which are within the range of 0.2 to 0.5 mm.

[0010] Optionally, two adjacent first protrusions have a first spacing, and two adjacent second protrusions have a second spacing, both the first spacing and the second spacing being within the range of 0.8 to 1.2 mm.

[0011] Optionally, the driving mechanism is a manual driving mechanism, which includes a handle and a lead screw assembly. The fixed part of the lead screw assembly is installed in the housing, and one end of the movable part of the lead screw assembly is connected to the handle and the other end is connected to the movable clamping block.

[0012] Optionally, the clamping assembly further includes a reinforcing block, which is connected to the movable clamping block and disposed on the side of the movable clamping block opposite to the fixed clamping block; the other end of the moving part of the lead screw assembly is connected to the movable clamping block through the reinforcing block.

[0013] Optionally, the driving mechanism is a pneumatic driving mechanism, which includes a cylinder, a piston that is slidably disposed in the inner cavity of the cylinder, and a piston rod that is fixedly connected to the piston and extends through the end cover of the cylinder. The end of the piston rod away from the piston is connected to the movable clamping block.

[0014] Optionally, the housing has a guide groove on the side of the fixed clamping block away from the movable clamping block, and the guide groove is configured for receiving the robot tendon rope for testing.

[0015] According to a second aspect of this application, a method for tensile testing of robotic tendons is provided, the method employing two test fixtures as described in the first aspect, the method comprising: Connect the mounting interface of one of the test fixtures to the upper chuck of the universal testing machine, and connect the mounting interface of the other test fixture to the lower chuck of the universal testing machine. One end of the robot tendon cable to be tested is clamped between the fixed clamp and the movable clamp of one of the test fixtures, and the other end of the robot tendon cable to be tested is clamped between the fixed clamp and the movable clamp of the other test fixture. Start the tensile program of the universal testing machine and read the maximum breaking force and elongation at break to complete the tensile test of the robot tendon ligament.

[0016] Optionally, the test method further includes: When the tendon rope of the robot to be tested is a tungsten wire rope and / or its diameter is <1.0 mm, the test fixture is selected as a test fixture with a manual drive mechanism; When the material of the robot tendon rope to be tested is organic fiber and / or its diameter is ≥1.0mm, the test fixture is selected as a test fixture with a pneumatic drive mechanism.

[0017] Compared with the prior art, the beneficial effects of this application are as follows: This application provides a tensile testing fixture for robot tendon ropes. The arc-shaped concave-convex anti-slip structure on the clamping surface of its clamping component can significantly improve the contact friction, effectively ensuring that there is no visible slippage during the tensile test and guaranteeing the authenticity of the test data. At the same time, the arc-shaped structure has no sharp edges, which can avoid the rigid sharp corners from squeezing and damaging the brittle tungsten wire rope and flexible fiber tendon rope, eliminating the problem of premature breakage at the clamping part and improving the effectiveness of the test. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a tensile testing fixture for robot tendons, as described in an embodiment of this application. Figure 1 ; Figure 2 for Figure 1 A magnified schematic diagram of a local structure; Figure 3 This is a schematic diagram of the structure of a tensile testing fixture for robot tendons, as described in an embodiment of this application. Figure 2 ; Figure 4 for Figure 3 A magnified schematic diagram of a local structure.

[0020] Explanation of reference numerals in the attached figures: 1. Test fixture; 11. Housing; 12. Mounting interface; 13. Clamping assembly; 131. Fixed clamping block; 1311. First clamping surface; 132. Movable clamping block; 1321. Second clamping surface; 133. Reinforcing block; 14. Drive mechanism; 141. Handle; 142. Lead screw assembly; 143. Cylinder; 144. Piston rod; 01. Robotic tendon tract. Detailed Implementation

[0021] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] In the description of this application, 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 this application and 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 this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0024] Reference Figures 1-4As shown, this application provides a tensile testing fixture for robot tendons. The testing fixture 1 includes a housing 11, a mounting interface 12, a clamping assembly 13, and a drive mechanism 14. The mounting interface 12 is connected to the housing 11 and is located at the end of the housing 11. The clamping assembly 13 is configured to clamp the robot tendon cable 01 to be tested; the clamping assembly 13 includes a fixed clamping block 131 and a movable clamping block 132 arranged opposite to each other along a first direction, and the fixed clamping block 131 is fixedly disposed on the housing 11. The drive mechanism 14 is mounted on the housing 11. The output end of the drive mechanism 14 is connected to the movable clamping block 132. The movable clamping block 132 can move in a first direction under the driving force of the drive mechanism 14 to move closer to or further away from the fixed clamping block 131. The fixed clamping block 131 has a first clamping surface 1311 disposed toward the movable clamping block 132. The first clamping surface 1311 has at least two first protrusions and at least two first recesses. The first protrusions and the first recesses are both constructed in an arc shape and are alternately disposed. The movable clamping block 132 has a second clamping surface 1321 disposed toward the fixed clamping block 131. The second clamping surface 1321 has at least two second protrusions and at least two second recesses. Both the second protrusions and the second recesses are constructed in an arc shape and are alternately disposed.

[0025] The core components of the tensile testing fixture for robot tendons provided in this application embodiment include a housing 11, a mounting interface 12, a clamping assembly 13, and a drive mechanism 14. The mounting interface 12 is assembled at the end of the housing 11 and fixedly connected to the housing 11. The clamping assembly 13 is specifically used for limiting and clamping various robot tendons to be tested. The drive mechanism 14 is fixedly installed on the surface of the housing 11 and provides a power source for the clamping action of the clamping assembly 13. The clamping assembly 13 includes a fixed clamping block 131 and a movable clamping block 132 arranged opposite to each other along a first direction. The fixed clamping block 131 is fixedly assembled on the housing 11 and its position remains constant. The movable clamping block 132 is a movable structure. The first clamping surface 1311 of the fixed clamping block 131 is provided with at least two arc-shaped first protrusions and at least two arc-shaped first recesses, which are arranged alternately. The second clamping surface 1321 of the movable clamping block 132 is provided with at least two arc-shaped second protrusions and at least two arc-shaped second recesses, which are also arranged alternately to form an interlaced fine tooth anti-slip texture structure.

[0026] In the tensile testing fixture for robot tendons provided in this application embodiment, the housing 11 serves as the load-bearing base of the entire testing fixture 1, providing a stable mounting support foundation for the other components; the mounting interface 12 is located at the end of the housing 11, used to realize the quick assembly and docking of the fixture with the universal testing machine; the drive mechanism 14 is fixed on the housing 11 as a whole, and its power output end is rigidly connected to the movable clamping block 132. During operation, the drive mechanism 14 outputs driving force to drive the movable clamping block 132 to make precise translational movements along the first direction. Through translational movements, the movable clamping block 132 moves closer to or away from the fixed clamping block 131; when the movable clamping block 132 moves closer to the fixed clamping block 131, the arc-shaped concave and convex structures of the two sets of clamping surfaces cooperate to clamp the tendon, completing the tendon fixation; when the movable clamping block 132 moves away from the fixed clamping block 131, the clamped tendon is released, completing the sample assembly and disassembly.

[0027] In the tensile testing fixture for robotic tendon chords provided in this application embodiment, alternating arc-shaped concave-convex anti-slip structures are used on two sets of clamping surfaces to replace traditional flat and wedge-shaped clamping surfaces. This significantly increases the contact friction between the clamping surfaces and the low-friction coefficient tendon chords, effectively solving the slippage problem during testing of smooth tendon chords such as PBO and UPE. This ensures no visible slippage during tensile testing, concentrating tendon chord breakage within the gauge length rather than at the clamping point, thus guaranteeing the authenticity of the test data. Simultaneously, the arc-shaped structure, without sharp edges, avoids damage to brittle tungsten wire and flexible fiber tendon chords caused by rigid sharp corners, preventing premature breakage at the clamping point and improving test effectiveness. The aforementioned integrated split clamping structure, combined with an independent drive structure, lays the structural foundation for adapting to the testing of tendon chords of different specifications and materials.

[0028] Reference Figure 2 , Figure 4 As shown, in one embodiment, the first protrusion is matched and docked with the second recess, and the second protrusion is matched and docked with the first recess.

[0029] In this specific example, the first protrusion of the fixed clamping block 131 is precisely matched and docked with the second recess of the movable clamping block 132, and at the same time, the second protrusion of the movable clamping block 132 is precisely matched and docked with the first recess of the fixed clamping block 131, so that the two sets of clamping surfaces form an interlocking mating structure, constituting a complete fine toothed anti-slip clamping working surface.

[0030] During the clamping operation, the first protrusion is embedded in the second recess, and the second protrusion is embedded in the first recess. The concave and convex structures of the two sets of clamping blocks fit together and overlap each other without any gaps. Throughout the clamping process, the fitting structure forms a multi-point wrapping limit on the surface of the tendon rope, rather than a local single-point contact, which fully constrains the radial and axial displacement of the tendon rope and meets the fitting and clamping requirements of the circular rope structure.

[0031] The aforementioned interlocking interlocking structure maximizes the effective contact area between the clamping surface and the tendon cord, further enhancing the clamping anti-slip performance and completely eliminating slippage during the tensile test of the low-friction tendon cord, thus avoiding the problem of low peak force. At the same time, the multi-point uniform wrapping clamping method ensures that the tendon cord is subjected to uniform force, avoiding local stress concentration, effectively preventing the crushing of UPE and PBO fibers and cracking of the tungsten wire cord surface, and significantly improving the accuracy and reliability of the test data.

[0032] Reference Figure 2 , Figure 4 As shown, in one embodiment, the first protrusion and the first recess have a first height difference, and the second protrusion and the second recess have a second height difference, both of which are within the range of 0.2 to 0.5 mm.

[0033] In this specific example, the first height difference and the second height difference are equal and both controlled within the range of 0.2 to 0.5 mm. This size range is the optimal unevenness size for adapting to the robot's micro-tendon ropes. During the fixture processing and assembly, the unevenness size of the clamping surfaces of the two sets of clamping blocks is strictly controlled to ensure that the height difference of all first protrusions and first recesses is uniformly within 0.2 to 0.5 mm, and the height difference of all second protrusions and second recesses is synchronously matched within this range. When clamping the tendon ropes, the micro-deformation clamping space formed by this height difference can provide appropriate wrapping and restraint for micro-tendon ropes of different diameters, preventing anti-slip failure due to too small a height difference and excessive compression due to too large a height difference.

[0034] In other words, a height difference range of 0.2 to 0.5 mm can ensure the anti-slip clamping effect while adapting to the brittle and flexible characteristics of tungsten wire rope and microfiber tendon rope, avoiding excessive pressure damage to the rope due to uneven structure, and also preventing slippage caused by insufficient friction due to too small a height difference.

[0035] Reference Figure 2 , Figure 4 As shown, in one embodiment, two adjacent first protrusions have a first spacing, and two adjacent second protrusions have a second spacing, both the first spacing and the second spacing being in the range of 0.8 to 1.2 mm.

[0036] In this specific example, the first and second spacings are equal and both set to 0.8–1.2 mm, achieving a uniform and regular arrangement of anti-slip fine teeth. During processing, the protrusions of both sets of clamping blocks are evenly distributed at equal intervals of 0.8–1.2 mm, ensuring a uniform density of anti-slip textures on the clamping surface. When clamping robot tendons of different thicknesses, the evenly arranged multi-point anti-slip structure can adaptively fit according to the rope diameter, forming a uniform multi-point clamping limit on the rope surface, without any local clamping gaps or over-clamping areas.

[0037] The 0.8-1.2mm evenly spaced arrangement design ensures that the anti-slip texture on the clamping surface is of moderate density, which can simultaneously accommodate the clamping needs of ultra-fine high-strength filaments and conventional large-diameter tendon ropes. This solves the problem of poor adaptability of traditional clamps and incompatibility with multi-specification tendon rope testing. The uniform clamping points can disperse tensile loads and avoid rope breakage caused by local stress concentration, further improving the stability of the testing process and the accuracy of data.

[0038] Reference Figure 1 , Figure 2 As shown, in one embodiment, the drive mechanism 14 is a manual drive mechanism, which includes a handle 141 and a lead screw assembly 142. The fixed part of the lead screw assembly 142 is installed on the housing 11, and one end of the movable part of the lead screw assembly 142 is connected to the handle 141 and the other end is connected to the movable clamping block 132.

[0039] In this specific example, the drive mechanism 14 adopts a manual drive structure, which is composed of a handle 141 and a lead screw assembly 142. The lead screw assembly 142 is divided into two structural parts: a fixed part and a moving part. The fixed part of the lead screw assembly 142 is fixedly assembled on the housing 11 to achieve overall structural positioning. The two ends of the moving part of the lead screw assembly 142 are respectively connected to the handle 141 and the movable clamping block 132, and the clamping action is achieved by manually operating the handle.

[0040] During operation, the operator manually rotates handle 141, which drives the moving part of lead screw assembly 142 to perform a linear translational motion. The moving part of the lead screw converts the rotational motion into a linear thrust, which in turn pushes the movable clamping block 132 to move along the first direction closer to the fixed clamping block 131, thus completing the tendon rope clamping. Rotating handle 141 in the opposite direction will cause the movable clamping block 132 to move in the opposite direction, releasing the tendon rope sample. Its overall transmission structure is stable and the action is highly controllable.

[0041] The manual screw drive structure offers high transmission precision and adjustable clamping force, making it suitable for testing tendon cords with diameters less than 1.0mm and tungsten wire ropes. Furthermore, the manual drive structure is simple, stable, and has a high load-bearing capacity, meeting the requirements for tensile testing of tendon cords under high-strength loads.

[0042] Reference Figure 1 , Figure 2 As shown, in one embodiment, the clamping assembly 13 further includes a reinforcing block 133, which is connected to the movable clamping block 132 and disposed on the side of the movable clamping block 132 opposite to the fixed clamping block 131; the other end of the moving part of the lead screw assembly 142 is connected to the movable clamping block 132 through the reinforcing block 133.

[0043] In this specific example, when the drive mechanism 14 is a manual drive mechanism, the clamping assembly 13 is additionally equipped with a reinforcing block 133. The reinforcing block 133 is fixedly connected to the side end face of the movable clamping block 132 opposite to the fixed clamping block 131. The moving part end of the lead screw assembly 142 is indirectly fixedly connected to the movable clamping block 132 through the reinforcing block 133, thereby achieving a reinforced connection of the power transmission.

[0044] Therefore, the thrust output by the moving part of the lead screw assembly 142 first acts on the reinforcing block 133, and then the reinforcing block 133 evenly transmits the thrust to the overall end face of the movable clamping block 132. During the entire tensile test, the reinforcing block 133 always maintains the force balance of the movable clamping block 132, avoiding the situation of unilateral force deviation or tilting of the movable clamping block 132, and ensuring the straightness of the clamping block's translation.

[0045] Furthermore, the reinforcing block 133 effectively strengthens the connection between the movable clamping block 132 and the lead screw assembly 142, dispersing transmission stress and preventing loosening of the connection and clamping block offsetting under long-term high-load testing conditions, thus improving the overall structural stability and service life of the fixture. Simultaneously, it ensures the accuracy of clamping block translation, keeping the clamping surfaces parallel and in contact, and ensuring uniform force on the tendon rope clamping, further enhancing the stability of test data. Optionally, the test fixture housing thickness corresponding to this manual drive mechanism is increased by 30% to 50% compared to conventional housings. The housing is made of 40Cr alloy steel and has undergone heat treatment, capable of withstanding ultimate loads greater than 2000N, making it suitable for high-strength load testing scenarios.

[0046] Reference Figure 3 , Figure 4 As shown, in one embodiment, the drive mechanism 14 is a pneumatic drive mechanism, which includes a cylinder 143, a piston that is slidably disposed in the inner cavity of the cylinder, and a piston rod 144 that is fixedly connected to the piston and extends through the cylinder end cover. The end of the piston rod 144 away from the piston is connected to the movable clamping block 132.

[0047] In this specific example, the drive mechanism 14 adopts a pneumatic drive structure, specifically including a cylinder 143, a piston, and a piston rod 144. The piston is slidably mounted in the inner cavity of the cylinder 143, dividing the inner cavity into two independent air chambers. The piston rod 144 is fixedly connected to the piston, and the end of the piston rod 144 protrudes through the end cover of the cylinder 143. The end of the piston rod 144 away from the piston is fixedly connected to the movable clamping block 132. The clamping action is achieved by pneumatic drive. At the same time, the cylinder 143 has a built-in return spring and is provided with an air inlet and an air outlet. The air inlet is connected to the air pressure regulating device interface of the universal testing machine through an air inlet channel.

[0048] When the pneumatic drive structure is working, external compressed air, after being regulated by a manual or proportional pressure regulating valve, enters the cylinder 143 through the air inlet. The air pressure pushes the piston to slide along the inner cavity of the cylinder 143, causing the piston rod 144 to extend linearly, which in turn pushes the movable clamping block 132 to move and clamp the tendon rope. After the test is completed, the air supply is cut off, and the return spring built into the cylinder 143 pushes the piston and piston rod 144 to return to their original positions, causing the movable clamping block 132 to release the tendon rope. The air pressure regulating device has an adjustment range of 0.1 to 0.8 MPa, and the clamping force can be precisely controlled by setting different air pressure values.

[0049] The pneumatic drive mechanism offers fast response, uniform and stable clamping force, and precise force control, enabling flexible clamping with low force and high precision. This allows for automated clamping operations, improving testing efficiency. Its minimum clamping force can be as low as 20N, providing gentle clamping under low-pressure conditions without causing any indentations or damage to smooth, flexible fiber surfaces such as UPE and PBO, meeting the requirements of high-precision non-destructive testing. Precise air pressure adjustment adapts to the clamping needs of different tendon ligament materials; low pressure is suitable for soft materials, while high pressure is suitable for high-friction scenarios, significantly expanding the clamp's adaptability.

[0050] In one embodiment, the housing 11 has a guide groove on the side of the fixed clamping block 131 away from the movable clamping block 132, the guide groove being configured for receiving the robot tendon rope for testing.

[0051] In this specific example, a guide groove is provided on the side of the fixed clamping block 131 away from the movable clamping block 132. The guide groove is a slot-type structure, mainly used to clamp and limit the robot tendon rope to be tested, so as to achieve pre-positioning before testing.

[0052] When assembling the tendon rope to be tested, the tendon rope is inserted into the guide groove. The guide groove limits and pre-fixes the tendon rope, making it vertically centered at the clamping center of the clamping assembly 13. With the guidance structure of the other end clamp, the upper and lower ends of the tendon rope are precisely aligned, ensuring that the tendon rope is in a vertically stretched state.

[0053] The guide groove effectively ensures that the upper and lower ends of the tendon rope of the robot under test are vertically aligned, avoiding the tendon rope tilting or uneven load during the tensile test, eliminating test data deviation caused by uneven force, simplifying the sample clamping process, improving clamping accuracy and efficiency, and ensuring the coaxiality requirements of the tensile test.

[0054] Another embodiment of this application provides a method for tensile testing of robotic tendons, the method employing two test fixtures 1 as described above, the method comprising: S101. Connect the mounting interface 12 of one of the test fixtures 1 to the upper clamp of the universal testing machine, and connect the mounting interface 12 of the other test fixture 1 to the lower clamp of the universal testing machine. S102. Clamp one end of the robot tendon rope to be tested between the fixed clamping block 131 and the movable clamping block 132 of one of the test fixtures 1, and clamp the other end of the robot tendon rope to be tested between the fixed clamping block 131 and the movable clamping block 132 of the other test fixture 1. S103. Start the tensile program of the universal testing machine and read the maximum breaking force and elongation at break to complete the tensile test of the robot tendon rope.

[0055] This embodiment discloses a tensile testing method for robot tendons. The testing method uses two test fixtures 1 as described in any of the above embodiments in conjunction with a universal testing machine to complete the test. The core process includes three core steps: fixture assembly, clamping of both ends of the tendon, and tensile test data acquisition. It is applicable to the mechanical performance testing of various robot tendons. At the same time, the two test fixtures with different drive structures have the same installation interface 12, which can realize quick interchangeable assembly.

[0056] In step S101, before the test, the fixture assembly is completed. The mounting interface 12 of one test fixture 1 is connected to the upper chuck of the universal testing machine, and the mounting interface 12 of the other test fixture 1 is connected to the lower chuck of the testing machine, ensuring coaxial alignment of the upper and lower fixtures. Then, in step S102, the two ends of the tendon rope to be tested are respectively clamped between the fixed clamping block 131 and the movable clamping block 132 of the two test fixtures 1, achieving stable clamping and straightening of the tendon rope through the fixture structure. After assembly, in step S103, the preset tensile program of the universal testing machine is started. The testing machine stretches the tendon rope at a uniform speed, collecting key parameters such as the maximum breaking force and elongation at break in real time until the tendon rope breaks, completing a single tensile test.

[0057] The testing method employs a dual-clamp symmetrical gripping approach, coupled with the clamps' dedicated anti-slip and anti-pinch structure, which completely solves the problems of slippage, pinching, and data distortion in traditional testing methods. This ensures that tendon ligament breakage occurs within the gauge length, accurately capturing the true tensile mechanical property parameters of the tendon ligament. Simultaneously, the unified installation interface 12 allows for quick clamp removal and replacement, simplifying the testing process and improving the adaptability and versatility of testing different types of tendon ligaments.

[0058] Reference Figure 1 , Figure 2 As shown, in one embodiment, the testing method further includes: When the tendon rope of the robot to be tested is a tungsten wire rope and / or its diameter is <1.0 mm, the test fixture is selected as a test fixture with a manual drive mechanism; When the material of the robot tendon rope to be tested is organic fiber and / or its diameter is ≥1.0mm, the test fixture is selected as a test fixture with a pneumatic drive mechanism.

[0059] In this specific example, test fixtures with corresponding drive types are matched based on the material and diameter characteristics of different tendon chords to achieve differentiated and precise testing. Specifically, two fixture selection conditions are divided according to two dimensions: whether the tendon chord is tungsten wire and whether its diameter is less than 1.0 mm, and whether the material is organic fiber and whether its diameter is greater than or equal to 1.0 mm.

[0060] In the actual testing process, the parameters of the tendon rope of the robot under test are first determined. If the tendon rope to be tested is a tungsten wire rope, or a fine high-strength rope with a diameter of less than 1.0 mm, a test fixture with a manual drive mechanism is selected. If the tendon rope to be tested is made of organic fibers such as UPE and PBO, or a thick rope with a diameter of 1.0 mm or greater, a test fixture with a pneumatic drive mechanism is selected. Automatic and adaptable clamping is achieved through air pressure adjustment to complete differentiated testing operations under different working conditions.

[0061] By using differentiated fixture selection methods, it is possible to specifically adapt to the testing needs of tendon cords of different materials and specifications, avoiding the shortcomings of a single fixture being unable to be compatible with multiple types of tendon cords, thereby greatly improving the versatility and accuracy of the testing method and fully covering the tensile testing scenarios of existing mainstream robot tendon cords.

[0062] The above embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of protection of this application. Any non-substantial changes and substitutions made by those skilled in the art based on this application shall fall within the scope of protection claimed by this application.

Claims

1. A tensile testing fixture for robot tendons, characterized in that, The test fixture (1) includes: Shell (11); Mounting interface (12), which is connected to the housing (11) and located at the end of the housing (11); A clamping assembly (13) is configured to clamp a robot tendon cable to be tested; the clamping assembly (13) includes a fixed clamping block (131) and a movable clamping block (132) disposed opposite to each other in a first direction, the fixed clamping block (131) being fixedly disposed on the housing (11). A drive mechanism (14) is installed on the housing (11). The output end of the drive mechanism (14) is connected to the movable clamp (132). The movable clamp (132) can move in a first direction under the driving force of the drive mechanism (14) to move closer to or further away from the fixed clamp (131). The fixed clamping block (131) has a first clamping surface (1311) facing the movable clamping block (132). The first clamping surface (1311) has at least two first protrusions and at least two first recesses. The first protrusions and the first recesses are both constructed in an arc shape and are alternately arranged. The movable clamping block (132) has a second clamping surface (1321) facing the fixed clamping block (131). The second clamping surface (1321) has at least two second protrusions and at least two second recesses. Both the second protrusions and the second recesses are constructed in an arc shape and are alternately arranged.

2. The tensile testing fixture for robot tendons according to claim 1, characterized in that, The first protrusion mates with the second recess, and the second protrusion mates with the first recess.

3. The tensile testing fixture for robot tendons according to claim 1 or 2, characterized in that, The first protrusion and the first recess have a first height difference, and the second protrusion and the second recess have a second height difference, both of which are within the range of 0.2 to 0.5 mm.

4. The tensile testing fixture for robot tendons according to claim 1 or 2, characterized in that, Two adjacent first protrusions have a first spacing, and two adjacent second protrusions have a second spacing, both of which are within the range of 0.8 to 1.2 mm.

5. The tensile testing fixture for robot tendons according to claim 1, characterized in that, The drive mechanism (14) is a manual drive mechanism, which includes a handle (141) and a lead screw assembly (142). The fixed part of the lead screw assembly (142) is installed on the housing (11), and one end of the movable part of the lead screw assembly (142) is connected to the handle (141) and the other end is connected to the movable clamp (132).

6. The tensile testing fixture for robot tendons according to claim 5, characterized in that, The clamping assembly (13) further includes a reinforcing block (133), which is connected to the movable clamping block (132) and disposed on the side of the movable clamping block (132) opposite to the fixed clamping block (131); the other end of the moving part of the lead screw assembly (142) is connected to the movable clamping block (132) through the reinforcing block (133).

7. The tensile testing fixture for robot tendons according to claim 1, characterized in that, The drive mechanism (14) is a pneumatic drive mechanism, which includes a cylinder (143), a piston that is slidably disposed in the inner cavity of the cylinder, and a piston rod (144) that is fixed to the piston and extends through the cylinder end cover. The end of the piston rod (144) away from the piston is connected to the movable clamp (132).

8. The tensile testing fixture for robot tendons according to claim 1, characterized in that, The housing (11) has a guide groove on the side of the fixed clamp (131) away from the movable clamp (132), and the guide groove is configured for the robot tendon rope for receiving the test.

9. A method for tensile testing of robotic tendons, characterized in that, The test method employs two test fixtures (1) as described in any one of claims 1-8, and the test method includes: Connect the mounting interface (12) of one of the test fixtures (1) to the upper chuck of the universal testing machine, and connect the mounting interface (12) of the other test fixture (1) to the lower chuck of the universal testing machine. One end of the robot tendon rope to be tested is clamped between the fixed clamping block (131) and the movable clamping block (132) of one of the test fixtures (1), and the other end of the robot tendon rope to be tested is clamped between the fixed clamping block (131) and the movable clamping block (132) of the other test fixture (1). Start the tensile program of the universal testing machine and read the maximum breaking force and elongation at break to complete the tensile test of the robot tendon ligament.

10. The method for tensile testing of robot tendons according to claim 9, characterized in that, The testing method also includes: When the tendon rope of the robot to be tested is a tungsten wire rope and / or its diameter is <1.0 mm, the test fixture is selected as a test fixture with a manual drive mechanism; When the material of the robot tendon rope to be tested is organic fiber and / or its diameter is ≥1.0mm, the test fixture is selected as a test fixture with a pneumatic drive mechanism.

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