Device and method for testing rigidity and retentivity of driving branch chain

Abstract

The invention discloses a device and a method for testing rigidity and retentivity of a driving branch chain. The device comprises a supporting module, a force loading module, a measuring module, a guiding module and a control module. The supporting module is used for fixing a to-be-measured driving branch chain, the force loading module, the measuring module and the guiding module; the force loading module comprises a servo electric cylinder, an electric cylinder connecting tool and an elastic loading device; the servo electric cylinder is connected with the supporting module; two ends of the electric cylinder connecting tool are respectively connected with the elastic loading device and the servo electric cylinder; the elastic loading device is connected with the guide module; the measuring module comprises a force measuring module and a deformation measuring module; the force measurement module is connected with the to-be-measured driving branch chain; the deformation measurement module is arranged at the tail end of the to-be-measured driving branch chain; the guiding module is arranged between the elastic loading device and the force measuring module; the control module is used for collecting data and controlling the servo electric cylinder and the to-be-tested driving branched chain to move; according to the invention, rigidity tests and rigidity retentivity tests of various driving branched chains are supported.

Description

Technical Field

[0001] The invention belongs to the field of equipment testing technology, and particularly relates to a device and method for testing the stiffness and stiffness retention of a driving branch chain. Background Art

[0002] Due to the advantages of a large task space to frame volume ratio and high stiffness, the robotic machining equipment built using parallel / hybrid robots is becoming an important option for solving the problem of in-situ machining of large and complex structural parts. As the core component of a parallel / hybrid robot, the stiffness and stiffness retention of the driving branch chain have an important impact on aspects such as the stiffness, machining accuracy, and service life of the entire robot. Therefore, the primary goal of building a high-performance robot is to manufacture a driving branch chain that meets the design index requirements, which requires both systematic theoretical research and relatively complete experimental testing technology.

[0003] However, most of the current testing technologies are for testing the performance of the entire parallel / hybrid robot. For example, CN202011350262.2 discloses a three-degree-of-freedom high-precision stiffness detection device for detecting the stiffness of a robot. However, there is still a large gap in the research on testing the stiffness and stiffness retention of the driving branch chain. Summary of the Invention

[0004] In view of the above problems, the invention provides a device and method for testing the stiffness and stiffness retention of a driving branch chain.

[0005] To achieve the above object, the invention adopts the following technical solutions:

[0006] A device for testing the stiffness and stiffness retention of a driving branch chain includes a driving branch chain to be tested, a support module, a force loading module, a measurement module, a guiding module, and a control module;

[0007] The support module is used to fix the driving branch chain to be tested, the force loading module, the measurement module, and the guiding module;

[0008] The force loading module includes a servo electric cylinder, an electric cylinder connection tooling, and an elastic loading device; the servo electric cylinder is connected to the support module; both ends of the electric cylinder connection tooling are respectively connected to the elastic loading device and the servo electric cylinder; the elastic loading device is connected to the guiding module and is used to absorb the impact force during the loading process;

[0009] The measurement module includes a force measurement module and a deformation measurement module; the force measurement module is connected to the driving branch chain to be tested; the deformation measurement module is arranged at the end of the driving branch chain to be tested;

[0010] The guiding module is arranged between the elastic loading device and the force measurement module and is used to flexibly connect the driving branch chain to be tested and the servo electric cylinder and guide the movement of both;

[0011] The control module is used for data acquisition of the force measurement module and the deformation measurement module and controls the movement of the servo electric cylinder and the drive branch chain to be measured.

[0012] A method for testing the stiffness of a drive branch chain includes:

[0013] (1) Divide the stroke of the drive branch chain to be measured evenly into M - 1 equal parts. Starting from the zero position of the drive branch chain to be measured, set M test points evenly, and denote the i-th test point as P i , corresponding to the stroke of the drive branch chain to be measured as q i ;

[0014] (2) Synchronously switch the servo electric cylinder and the drive branch chain to be measured to the zero position of the drive branch chain to be measured, and at the same time move the deformation measurement module to the end of the drive branch chain to be measured and fasten it;

[0015] (3) Increase the load on the drive branch chain to be measured to the specified maximum value at a certain interval value. Keep each load value for a set time, record each sampling value, and at the same time synchronously collect two reading values x n,1 and x n,2 corresponding to each load value through the deformation measurement module, and obtain a set of data on the corresponding relationship between the loading force and deformation of the drive branch chain;

[0016] The loading force of the drive branch chain: f n =|F n -F0|

[0017] Deformation:

[0018] In the formula: F n is the n-th sampling value, F0 represents the reading value of the force measurement module when no load is applied; x 0,1 and x 0,2 represent two reading values collected by the deformation measurement module when no load is applied, k is the reading value number, and N is the number of samplings;

[0019] (4) Unload the drive branch chain to be measured, and then load the drive branch chain to be measured in the opposite direction, and repeat step (3) to obtain another set of data on the corresponding relationship between the loading force and deformation of the drive branch chain;

[0020] (5) Independently load p times in both the tensile and compressive directions to obtain multiple sets of valid data;

[0021] (6) Use the motion control card to synchronously switch the servo electric cylinder and the drive branch chain to the next test point position. After moving the deformation measurement module to the end of the drive branch chain to be measured and fastening it, repeat steps (3), (4), and (5) until valid data for all test points are obtained.

[0022] A method for testing the stiffness retention of a drive branch chain includes:

[0023] (1) Testing to obtain the initial stiffness value of the drive branch chain to be tested;

[0024] (2) Setting the servo electric cylinder to a control mode of active force input and passive position following; setting the running mileage or running time within one running cycle of the drive branch chain to be tested, the testing speed, and the load force to be applied;

[0025] (3) Starting the operation of the drive branch chain to be tested according to the set running mileage or running time and the testing speed;

[0026] (4) After the drive branch chain to be tested finishes running according to the set running mileage or running time, using the drive branch chain stiffness testing method to test the stiffness value of the drive branch chain to be tested after this running cycle;

[0027] (5) Repeating steps (2), (3), and (4) to carry out the stiffness retention test for the next running cycle until the stiffness of the drive branch chain to be tested fails or reaches the set cut-off mileage / time.

[0028] Compared with the prior art, the remarkable advantages of the present invention are:

[0029] 1. The testing device of the present invention is provided with an elastic loading device containing disc springs between the drive branch chain and the servo electric cylinder, which can protect the testing device from large impacts and vibrations during loading and operation; at the same time, by converting the deformation amount of the disc spring into the corresponding loading force through the elastic loading device, accurate force loading can be achieved;

[0030] 2. When the stiffness of the testing device of the present invention is tested, the stiffness data of the drive branch chain at different strokes can be obtained, and then the correlation function between the stiffness of the drive branch chain and the stroke can be obtained, which meets the actual application requirements of the parallel / hybrid mechanism;

[0031] 3. When the stiffness retention of the testing device of the present invention is tested, due to the excellent dynamic performance of the servo electric cylinder, the force loading module can simulate the alternating load received by the drive branch chain in the actual working condition, making the test have a high degree of realism;

[0032] 4. The drive branch chain stiffness and its retention testing device of the present invention has a simple structure, a compact layout, and real-time data monitoring; and the force loading range is large, which can not only meet the stiffness and its retention testing of different models and forms of drive branch chains, but also effectively detect the maximum load-bearing capacity of the drive branch chain. Description of the Drawings

[0033] Figure 1 It is a schematic diagram of the overall structure of Embodiment 1 of the present invention.

[0034] Figure 2Explosion schematic diagram of the local part at the driving branch support seat in Embodiment 1 of the present invention.

[0035] Figure 3 Explosion schematic diagram of the force measurement module and the deformation measurement module in Embodiment 1 of the present invention.

[0036] Figure 4 Schematic diagram of the control module in Embodiment 1 of the present invention.

[0037] Figure 5 Schematic diagram of the structure of the elastic loading device in Embodiment 1 of the present invention.

[0038] Figure 6 Explosion schematic diagram of the guiding module in Embodiment 1 of the present invention.

[0039] Figure 7 Overall structure schematic diagram of Embodiment 2 of the present invention.

[0040] Figure 8 Explosion schematic diagram of the local part at the active telescopic leg support seat in Embodiment 2 of the present invention.

[0041] Figure 9 Overall structure schematic diagram of Embodiment 3 of the present invention.

[0042] Figure 10 Explosion schematic diagram of the local part at the spherical pair connector in Embodiment 3 of the present invention.

[0043] The meanings represented by the numbers in the figure are as follows:

[0044] 1. Driving branch chain, 2. Support module, 21. Cast iron platform, 22. Servo electric cylinder support seat, 23. Driving branch chain support seat, 24. Servo electric cylinder tooling plate, 25. Guide rail pair tooling plate, 26. Driving branch chain tooling plate, 3. Force loading module, 31. Servo electric cylinder, 32. Electric cylinder connection tooling, 33. Elastic loading device, 331. Housing, 332. Connecting end cover, 333. Connecting rod, 334. Front pressure head, 335. Rear pressure head, 336. Disc spring, 337. Support seat, 338. Copper bushing, 3311. Front positioning pit, 3312. Rear positioning pit, 4. Measuring module, 41. Force measuring module, 42. Deformation measuring module, 411. S-type tension and compression sensor, 412. Connector, 421. Deformation measuring plate, 422. Measuring plate connection tooling, 423. L-shaped plate, 424. L-shaped plate connection tooling, 425. Contact displacement sensor, 5. Control module, 51. Branch chain motor driver, 52. Branch chain motor encoder, 53. Servo electric cylinder motor driver, 54. Motion control card, 55. Data acquisition system, 6. Guide module, 61. Linear guide rail, 62. Guide slider, 63. Measuring slider, 64. Guide rail clamp, 65. Sliding plate, 66. First floating joint, 67. Second floating joint, 68. Force sensor connection tooling;

[0045] 27. Active telescopic leg support seat, 28. Active telescopic leg fixed support plate, 29. Active telescopic leg tooling plate;

[0046] 30. Six-degree-of-freedom driving branch chain front support seat, 413. Ball pair connector. Detailed implementation method

[0047] The present invention will be further described in detail below in conjunction with embodiments and the accompanying drawings:

[0048] Embodiment 1:

[0049] Combined with Figure 1 , a driving branch chain stiffness and its maintainability test device in this embodiment includes a support module 2, a force loading module 3, a measuring module 4 and a control module 5.

[0050] The driving branch chain 1 to be measured is a three-degree-of-freedom driving branch chain, which is composed of a two-degree-of-freedom Hooke hinge and a single-degree-of-freedom active telescopic leg;

[0051] Combined with Figure 2 , the support module 2 includes a cast iron platform 21, a servo electric cylinder support seat 22, a driving branch chain support seat 23, and a servo electric cylinder tooling plate 24, a guide rail pair tooling plate 25 and a driving branch chain tooling plate 26 fixedly installed on the cast iron platform 21; the driving branch chain 1 to be measured is fixedly installed on the driving branch chain support seat 23;

[0052] The force loading module 3 includes a servo electric cylinder 31, an electric cylinder connection tooling 32, and an elastic loading device 33; the servo electric cylinder 31 is connected to the servo electric cylinder support seat 22 through a positioning pin; one end of the electric cylinder connection tooling 32 is provided with an internal thread and is connected to the external thread of the telescopic rod of the servo electric cylinder 31, and the other end is connected to the elastic loading device 33 through a bolt;

[0053] Combined with Figure 3 , the measurement module 4 includes a force measurement module 41 and a deformation measurement module 42; the force measurement module 41 includes an S-type tension and compression sensor 411 and a connector 412; the deformation measurement module 42 includes a deformation measurement plate 421, a measurement plate connection tooling 422, an L-shaped plate 423, an L-shaped plate connection tooling 424, and a contact displacement sensor 425; the deformation measurement plate 421 is fixedly connected to the measurement plate connection tooling 422 through a bolt; the measurement plate connection tooling 422 is fixedly connected to the end of the to-be-tested driving branch chain 1 through a set screw; both ends of the connector 412 are provided with external threads, one end of the external thread is connected to the internal thread at the end of the to-be-tested driving branch chain 1, and the other end of the external thread is connected to the internal thread at one end of the S-type tension and compression sensor 411; two L-shaped plates 423 are fixedly connected to the left and right sides of the L-shaped plate connection tooling 424; the L-shaped plate 423 is provided with a through hole capable of passing through the contact displacement sensor 425, and the contact displacement sensor 425 is fixedly connected by tightening the bolt to reduce the diameter of the through hole; the contact displacement sensor 425 is vertically in contact with the deformation measurement plate 421 with a certain preload. After the force loading module 3 applies a load to the to-be-tested driving branch chain 1, the elastic deformation at the end of the to-be-tested driving branch chain 1 is obtained by measuring the displacement of the deformation measurement plate 421.

[0054] Combined with Figure 4 , the control module 5 includes a branch chain motor driver 51 and a branch chain motor encoder 52 connected to the servo motor of the driving branch chain 1; a servo electric cylinder motor driver 53 connected to the servo motor of the servo electric cylinder 31; a motion control card 54 connected to the branch chain motor driver 51 and the servo electric cylinder motor driver 53; a data acquisition system 55 connected to the branch chain motor encoder 52, the S-type tension and compression sensor 411, and the contact displacement sensor 425.

[0055] Combined with Figure 5, the elastic loading device 33 includes a housing 331, a connecting end cover 332, a connecting rod 333, a front pressing head 334, a rear pressing head 335, a disc spring 336, a support seat 337 and a copper bushing 338; the housing 331 is connected to the electric cylinder connection tooling 32, the connecting end cover 332 is connected to the guiding module 6, the housing 331 is sleeved inside the connecting end cover 332 and can slide relative to the connecting end cover 332 and the support seat 337, external threads are provided at both ends of the connecting rod 333, after the connecting rod 333 passes through the housing 331, the external thread at one end is connected to the internal thread of the support seat 337, and the other end is connected to the connecting end cover 332 through a nut; the front pressing head 334, the rear pressing head 335 and two groups of disc springs 336 are installed on the shaft bodies on both sides of the support seat 337, a group of disc springs 336 are provided between the front pressing head 334, the rear pressing head 335 and the support seat 337, the front pressing head 334 and the rear pressing head 335 can slide on the shaft bodies on both sides of the support seat 337, a copper bushing 338 is provided on each side inside the housing 331, the front pressing head 334 and the rear pressing head 335 are respectively located on both sides inside the housing 331, and the copper bushing 338 plays a guiding role for the front pressing head 334 and the rear pressing head 335; front positioning pits 3311 and rear positioning pits 3312 are provided inside the housing 331, which are respectively used to contact the hemispherical structures provided at the heads of the front pressing head 334 and the rear pressing head 335.

[0056] When the servo electric cylinder 31 makes an extending movement, the telescopic rod of the servo electric cylinder 31 drives the rear positioning pit 3312 on the housing 331 to move closer to the rear pressing head 335, realizing the contact between the rear positioning pit 3312 and the rear pressing head 335; when the rear positioning pit 3312 contacts the rear pressing head 335, the rear pressing head 335 moves with the housing 331 to compress the disc spring 336 on the same side, and transmits the load corresponding to the deformation amount of the disc spring 336 to the support seat 337 and the connecting rod 333, and further transmits it to the connecting end cover 332, realizing the loading of the compression force on the drive chain 1 to be measured; when the servo electric cylinder 31 makes a retracting movement, the telescopic rod of the servo electric cylinder 31 drives the front positioning pit 3311 on the housing 331 to move closer to the front pressing head 334, realizing the contact between the front positioning pit 3311 and the front pressing head 334; when the front positioning pit 3311 contacts the front pressing head 334, the front pressing head 334 moves with the housing 331 to compress the disc spring 336 on the same side, and transmits the load corresponding to the deformation amount of the disc spring 336 to the support seat 337 and the connecting rod 333, and further transmits it to the connecting end cover 332, realizing the loading of the tensile force on the drive chain 1 to be measured.

[0057] The described test device for the stiffness and its maintainability of the drive chain further includes a guiding module 6;

[0058] Combined Figure 6, the guiding module includes a linear guide rail 61, a guiding slider 62, a measuring slider 63, a rail clamp 64, a sliding plate 65, a first floating joint 66, a second floating joint 67, and a force sensor connection tooling 68; the linear guide rail 61 is fixedly connected to the guide pair tooling plate 25 by bolts; the guiding slider 62, the measuring slider 63, and the rail clamp 64 are installed on the linear guide rail 61; the sliding plate 65 is connected to the guiding slider 62 by bolts, and both the measuring slider 63 and the rail clamp 64 are connected to the L-shaped plate connection tooling 424 by bolts; through holes are provided on both sides of the sliding plate 65 and are connected to the first floating joint 66 and the second floating joint 67 by bolts. The other end of the first floating joint 66 is fixedly connected to the connection end cover 332 of the elastic loading device 33 by a nut, and the external thread at the other end of the second floating joint 67 is connected to the internal thread at one end of the force sensor connection tooling 68; the external thread at the other end of the force sensor connection tooling 68 is connected to the internal thread at one end of the S-shaped tension and compression force sensor 411.

[0059] Combined with Figure 4 , a method for testing the stiffness and its maintainability of a driving branch chain, using the testing device for the stiffness and its maintainability of a driving branch chain described above. The testing method includes a driving branch chain stiffness testing method and a stiffness maintainability testing method. The testing process includes two aspects. One is the installation of the driving branch chain 1 to be tested, the support module 2, the force loading module 3, the measuring module 4, and the guiding module 6. The other is to respectively carry out the testing and analysis of stiffness and stiffness maintainability.

[0060] The installation of the driving branch chain 1 to be tested, the support module 2, the force loading module 3, the measuring module 4, and the guiding module 6 includes the following steps:

[0061] Step 1: Install the support module 2, the force loading module 3, and the guiding module 6: Through the pin hole fit between the servo electric cylinder support seat 22 and the servo electric cylinder 31, install the force loading module 3 on the servo electric cylinder support seat 22, and at the same time adjust the coaxiality between the force loading module 3 and the guiding module 6; after fixedly installing the force loading module 3 and the guiding module 6, fixedly connect the elastic loading device 33 of the force loading module 3 to the first floating joint 66 of the guiding module 6 by threaded connection;

[0062] Step 2. Install the measurement module 4 and the drive branch chain 1 to be measured: Fix and install the drive branch chain 1 to be measured on the drive branch chain support seat 23 through threaded connection, install the measurement module 4 at the end of the drive branch chain 1 to be measured, and at the same time adjust the coaxiality between the drive branch chain 1 to be measured and the guiding module 6; after the drive branch chain tooling plate 26 is fixedly installed, fixedly connect the S-shaped tension and compression sensor 411 of the force measurement module 41 with the force sensor connection tooling 68 of the guiding module 6 through threaded connection, fixedly connect the L-shaped plate connection tooling 424 of the deformation measurement module 42 with the measurement slider 63 and the guide rail clamp 64 of the guiding module 6, and install two L-shaped plates 423 and the contact displacement sensor 425 according to the product technical requirements;

[0063] Step 3. Eliminate the installation clearance: After zeroing the position of the drive branch chain 1 to be measured, perform a preloading to eliminate the installation clearance, and record the zero position information at the same time.

[0064] The stiffness test and analysis of the drive branch chain include the following steps:

[0065] Step 1. Conduct a stiffness test:

[0066] (1) Divide the stroke of the drive branch chain 1 to be measured evenly into M - 1 equal parts, starting from the zero position of the drive branch chain 1 to be measured, set M test points evenly, and denote the i-th test point as P i , corresponding to the stroke of the drive branch chain 1 being q i (i = 1 to M);

[0067] (2) Use the motion control card 54 to synchronously switch the servo electric cylinder 31 and the drive branch chain 1 to be measured to the zero position of the drive branch chain 1 to be measured. At the same time, move the L-shaped plate connection tooling 424 to make the contact displacement sensor 425 contact the deformation measurement plate 421 vertically with a certain preloading amount, and then tighten the guide rail clamp 64;

[0068] (3) Apply a load to the drive branch chain 1 to be measured at a certain interval value until the specified maximum value. Keep each load value constant for 30 - 60 seconds, and record each sampling value F n (n = 1, 2, 3…, N), and at the same time synchronously collect the readings x n,1 and x n,2 (n = 1, 2, 3…, N) of the two contact displacement sensors 425 corresponding to each load value, obtaining a set of data on the corresponding relationship between the loading force and deformation of the drive branch chain; where F n is the n-th sampling value, x n,1 is the n-th reading of the first contact displacement sensor 425, x n,2 is the n-th reading of the second contact displacement sensor 425; N is the number of samplings.

[0069] The loading force of the drive branch chain: fn =|F n -F0|(n=1,2,3…,N);

[0070] Deformation: k is the serial number or reading value serial number of the contact displacement sensor 425;

[0071] Where: F0 represents the reading value of the S-type tension and pressure sensor 411 when there is no load; x 0,1 and x 0,2 Indicates the reading values ​​of the two contact displacement sensors 425 when no load is applied;

[0072] (4) Unloading the drive branch chain 1 to be tested, then loading the drive branch chain 1 in the opposite direction, repeating step (3), and obtaining another set of data on the corresponding relationship between the loading force and deformation of the drive branch chain. According to the difference in the directions of the two load applications, the two sets of data are regarded as the test results of the drive branch chain 1 under tension and compression, respectively.

[0073] (5) Repeat the independent loading p times in the tension and compression directions to obtain multiple sets of valid data;

[0074] (6) Using the motion control card 54, the servo electric cylinder 31 and the drive branch chain 1 are synchronously switched to the next test point, and at the same time, the clamping part of the guide rail clamp 64 is loosened, and the L-shaped plate connecting fixture 424 is moved to the contact displacement sensor 425 to vertically contact the deformation measurement plate 421 with a certain preload; after tightening the guide rail clamp 64, steps (3), (4), and (5) are repeated until valid data of all test points are obtained;

[0075] Step 2: Calculate the stiffness value of each test point of the drive branch chain 1: Draw the stiffness value of the drive branch chain at the test point P i Loading force-deformation data curve under tension and compression state, the average value obtained after linear fitting slope of p groups of loading force and deformation data under each state is the driving branch chain 1 at the test point P i The stiffness value under the corresponding state, and the tensile stiffness and compressive stiffness of the i-th test point are k s,i and k c,i (i=1~M);

[0076] Step 3: Calculate the correlation function between the stiffness of the driving branch chain 1 and the stroke: Let the tensile stiffness and compressive stiffness of the driving branch chain be k respectively s and k c , the travel distance is q, and the least square method is used for fitting. Let k s =(a s +b s q) -1 , k c =(a c +bc q) -1 , where a s and a c respectively represent the tensile and compressive compliances of the driving branch chain obtained by fitting that do not change with the stroke, and b s and b c respectively represent the ratios of the tensile and compressive compliances of the driving branch chain that change with the stroke to the stroke q obtained by fitting; according to calculate a s , according to calculate b s ; according to calculate a c , according to calculate b c .

[0077] The test and analysis of the stiffness retention of the driving branch chain include the following steps:

[0078] Step 1: Conduct a stiffness retention test:

[0079] (1) Adopt the driving branch chain stiffness test method to test and obtain the initial stiffness value of the driving branch chain 1;

[0080] (2) Set the servo electric cylinder 31 to the control mode of force active input and position passive following; set the running mileage or running time of the driving branch chain 1 within one running cycle, the test speed, and the load force to be applied;

[0081] (3) Start the driving branch chain 1 according to the set running mileage or running time and test speed;

[0082] (4) When the driving branch chain 1 finishes running according to the set running mileage or running time, adopt the driving branch chain stiffness test method to test the stiffness value of the driving branch chain 1 after this running cycle;

[0083] (5) Repeat steps (2), (3), and (4) to conduct the stiffness retention test of the next running cycle until the stiffness of the driving branch chain 1 fails or reaches the set cut-off mileage / time;

[0084] Step 2: Study the stiffness retention of the driving branch chain: Process the above multiple groups of data, draw the variation law diagram of the stiffness of the driving branch chain 1 with the running mileage or running time within the full test cycle, and study the stiffness retention law of the driving branch chain.

[0085] Example 2:

[0086] Combined with Figure 7 and Figure 8, the difference between Embodiment 2 and Embodiment 1 is that the drive branch chain 1 to be measured is a single-degree-of-freedom active telescopic leg, the drive branch chain support seat 23 is replaced by an active telescopic leg support seat 27, and an active telescopic leg fixing support plate 28 is added. The active telescopic leg fixing support plate 28 is connected to the active telescopic leg support seat 27 by bolts, and the single-degree-of-freedom active telescopic leg is fastened between the active telescopic leg support seat 27 and the active telescopic leg fixing support plate 28. In addition, the drive branch chain tooling plate 26 is replaced by an active telescopic leg tooling plate 29, and the remaining installation requirements and test methods are the same as those in Embodiment 1, and the stiffness and its maintainability test of the single-degree-of-freedom active telescopic leg can be carried out.

[0087] Embodiment 3:

[0088] Combined with Figure 9 and Figure 10 , the difference between Embodiment 3 and Embodiment 1 is that the drive branch chain 1 to be measured is a six-degree-of-freedom drive branch chain, and the six-degree-of-freedom drive branch chain is composed of a two-degree-of-freedom Hooke's joint, a single-degree-of-freedom active telescopic leg, and a three-degree-of-freedom spherical pair. In addition, the connector 412 is a spherical pair connector 413, and the measuring plate connection tooling 422 is fixedly connected to the spherical pair connector 413 by set screws. At the same time, a six-degree-of-freedom drive branch chain front support seat 29 is added and the second floating joint 67 is removed. The force sensor connection tooling 68 is directly fixedly connected to the sliding plate 65 by bolts. The six-degree-of-freedom drive branch chain front support seat 29 is fixedly installed on the cast iron platform, and the drive branch chain 1 to be measured is fixedly installed on the drive branch chain support seat 23 and the six-degree-of-freedom drive branch chain front support seat 29. The remaining installation requirements and test methods are the same as those in Embodiment 1, and the stiffness and its maintainability test of the six-degree-of-freedom drive branch chain can be carried out.

[0089] Although the present invention has been described above in conjunction with the accompanying drawings, the present invention is not limited to the above specific embodiments. The structures, connection methods, etc. of the components in the above specific embodiments are only illustrative and can be changed. Any equivalent transformation or improvement made on the basis of the technical solution of the present invention shall fall within the protection scope of the present invention.

Claims

1. A driving branch chain stiffness and retention testing device, characterized in that: It includes a support module, a force loading module, a measuring module, a guiding module and a control module; The support module is used to fix the drive branch chain to be tested, the force loading module, the measuring module and the guide module; The force loading module includes a servo electric cylinder, an electric cylinder connecting tool and an elastic loading device; the servo electric cylinder is connected to the support module; the two ends of the electric cylinder are respectively connected to the elastic loading device and the servo electric cylinder; the elastic loading device is connected to the guide module to absorb the impact force of the loading process; The measuring module includes a force measuring module and a deformation measuring module; the force measuring module is connected to the drive branch chain to be measured; the deformation measuring module is arranged at the end of the drive branch chain to be measured; The guide module is arranged between the elastic loading device and the force measuring module, and is used to flexibly connect the drive branch chain to be tested and the servo electric cylinder, and guide the movement of the two; The control module is used for data collection of the force measurement module and the deformation measurement module and for controlling the movement of the servo electric cylinder and the drive branch chain to be measured.

2. The driving branch chain stiffness and retention testing device according to claim 1, characterized in that: The elastic loading device includes a shell, a connecting end cover, a connecting rod, a front pressure head, a rear pressure head, a disc spring, a support seat and a guide sleeve; the shell is connected to the electric cylinder connecting tooling, the connecting end cover is connected to the guide module, the shell is sleeved in the connecting end cover, and can slide relative to the connecting end cover and the support seat, one end of the connecting rod passes through the shell and is connected to the support seat, and the other end is connected to the connecting end cover; the front pressure head, the rear pressure head and two groups of disc springs are installed on the shafts on both sides of the support seat, and a group of disc springs are provided between the front pressure head, the rear pressure head and the support seat, the front pressure head and the rear pressure head can slide on the shafts on both sides of the support seat, and a guide sleeve is provided on each side of the shell to guide the front pressure head and the rear pressure head; a front positioning pit and a rear positioning pit are provided inside the shell, which are respectively used to contact the hemispherical structures of the front pressure head and the rear pressure head.

3. The driving branch chain stiffness and retention testing device according to claim 1, characterized in that: The force measurement module includes an S-type tension and pressure sensor and a connector; the deformation measurement module includes a deformation measurement plate, a measurement plate connecting tooling, a mounting plate, a mounting plate connecting tooling and a contact displacement sensor; the deformation measurement plate is fixedly connected to the measurement plate connecting tooling; the measurement plate connecting tooling is fixedly connected to the end of the drive branch chain to be measured; the two ends of the connector are respectively connected to the drive branch chain to be measured and the S-type tension and pressure sensor; the two mounting plates are fixedly connected to the left and right sides of the mounting plate connecting tooling; the contact displacement sensor is fixed on the mounting plate.

4. The driving branch chain stiffness and retention testing device according to claim 1, characterized in that: The support module includes a platform and a servo electric cylinder support seat fixed on the platform, a fixed support seat for the drive branch chain to be tested, and a guide rail pair tooling plate; the servo electric cylinder support seat is used to install the servo electric cylinder, the fixed support seat for the drive branch chain to be tested is used to fix the drive branch chain to be tested, and the guide rail pair tooling plate is used to fix the guide module.

5. The driving branch chain stiffness and retention testing device according to claim 1, characterized in that: The guide module includes a linear guide rail, a guide slider, a measuring slider, a guide rail clamp, a sliding plate, a first floating joint, a second floating joint and a force sensor connecting tooling; the linear guide rail is fixed on the supporting module; the guide slider, the measuring slider and the guide rail clamp are installed on the linear guide rail; the sliding plate is connected to the guide slider, and the measuring slider and the guide rail clamp are both connected to the deformation measuring module; the sliding plate is respectively connected to the first floating joint and the second floating joint, the first floating joint is fixed to the elastic loading device, and the second floating joint is connected to the force measuring module.

6. A method for testing the stiffness of a drive branch chain, characterized in that: A driving branch chain stiffness and retention testing device as described in claims 1 to 5, comprising: (1) Divide the travel of the drive branch chain to be tested into M-1 equal parts, and evenly set M test points starting from the zero point of the drive branch chain to be tested, and record the i-th test point as P i , the corresponding driving branch chain stroke to be tested is q i ; (2) Synchronously switch the servo electric cylinder and the drive branch chain to be tested to the zero position of the drive branch chain to be tested, and at the same time move the deformation measurement module to the end of the drive branch chain to be tested and tighten it; (3) Increase the load of the drive branch chain to be tested to the specified maximum value at a certain interval. Each load value is maintained for a set time, and each sampling value is recorded. At the same time, the deformation measurement module synchronously collects two reading values ​​x corresponding to each load value. n,1 and x n,2 , and obtain a set of data on the corresponding relationship between the driving branch chain loading force and deformation; The driving branch chain loading force: f n =|F n -F0| Deformation: Where: F n is the nth sampling value, F0 represents the reading value of the force measurement module when there is no load; x 0,1 and x 0,2 Indicates the two reading values ​​collected by the deformation measurement module when not loaded, k is the reading value number, and N is the number of samples; (4) unloading the drive branch chain to be tested, then loading the drive branch chain to be tested in the opposite direction, repeating step (3), and obtaining another set of data on the corresponding relationship between the load force and deformation of the drive branch chain; (5) Repeat the independent loading p times in the tension and compression directions to obtain multiple sets of valid data; (6) Use the motion control card to synchronously switch the servo electric cylinder and the drive branch chain to the next test point, move the deformation measurement module to the end of the drive branch chain to be tested and tighten it, and repeat steps (3)(4)(5) until valid data of all test points are obtained.

7. The driving branch chain stiffness testing method according to claim 6, characterized in that: It also includes the calculation of the relationship between the stiffness and stroke of the tested drive branch chain: The tensile stiffness and compressive stiffness of the driving chain are k s and k c , the travel distance is q, and the least square method is used for fitting. Let k s =(a s +b s q) -1 , k c =(a c +b c q) -1 , where a s and a c They represent the tensile and compressive compliance of the driving chain obtained by fitting, which does not change with the stroke, and b s and b c They represent the ratios of the tensile and compressive compliances of the driving branch chain obtained with the stroke to the stroke q respectively; The tensile stiffness and compressive stiffness of the i-th test point are k s,i and k c,i ,according to Calculate a s ,according to Calculate b s ;according to Calculate a c ,according to Calculate b c .

8. A method for testing the stiffness retention of a drive branch chain, characterized in that: The driving branch chain stiffness testing method according to claim 6 comprises: (1) The initial stiffness value of the drive branch chain to be tested is obtained by testing; (2) Set the servo electric cylinder to actively input force and passively follow the position; set the running mileage or running time within one operating cycle of the drive branch chain to be tested, the test speed, and the load force to be applied; (3) starting the drive branch chain to be tested according to the set running mileage or running time and test speed; (4) After the drive branch chain to be tested has completed its operation according to the set mileage or operating time, the drive branch chain stiffness test method is used to test the stiffness value of the drive branch chain to be tested after this operating cycle; (5) Repeat steps (2), (3), and (4) to carry out the stiffness retention test for the next operating cycle until the stiffness of the drive branch chain to be tested fails or reaches the set cut-off mileage / time.

9. A driving branch chain stiffness and retention testing device according to claims 1-5, wherein the installation method thereof comprises: Step 1: Install the support module, force loading module and guide module: install the force loading module on the support module, and adjust the coaxiality between the force loading module and the guide module; after the force loading module and the guide module are fixedly installed, connect the elastic loading device of the force loading module with the guide module; Step 2: Install the measuring module and the drive branch chain to be tested: fix the drive branch chain to be tested on the support module, install the measuring module at the end of the drive branch chain to be tested, and adjust the coaxiality between the drive branch chain to be tested and the guide module; connect the measuring module to the guide module; Step 3: Eliminate installation gap: After adjusting the position of the drive branch chain to be tested to zero, perform a pre-load to eliminate the installation gap and record the zero point position information at the same time.

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