A method and device for testing mechanical properties of a continuum robot

Abstract

The present disclosure discloses a method for testing the mechanical properties of a continuum robot, including the steps of testing the torsion resistance and stiffness of the continuum robot. The present disclosure also discloses a device for testing the mechanical properties of a continuum robot, which can simultaneously test the torsion resistance and stiffness of the continuum robot.

Description

Technical Field

[0001] The present invention belongs to the field of robot technology, and in particular relates to a method and a device for testing the mechanical performance of a continuum robot. Background Art

[0002] Thanks to its flexibility and compliance, continuum robots have shown good application prospects in minimally invasive surgery, post-earthquake search and rescue, pipeline detection and other fields. However, at present, the performance evaluation of continuum robots is mostly focused on kinematics, such as end trajectory tracking and shape detection, and there are few performance evaluations on stiffness and torsion. These performances largely determine the load capacity and torsion resistance of continuum robots, and are key factors in ensuring their precise movement and reliability.

[0003] Some traditional methods measure mechanical properties such as load capacity by applying external loads to continuum robots and evaluating their motion performance based on loaded working conditions. However, these methods often cannot intuitively characterize the mechanical properties of continuum robots. Summary of the invention

[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a method and device for testing the mechanical properties of a continuum robot, which method and device can quantitatively test the torsional resistance and stiffness performance of the continuum robot.

[0005] To achieve the above objectives, the present disclosure provides the following technical solutions:

[0006] A method for testing the mechanical properties of a continuum robot, the continuum robot comprises a continuum robot arm connected by a drive cable, a first target ball seat and a second target ball seat are arranged at the end of the continuum robot arm, a first optical target ball is arranged on the first target ball seat, and a second optical target ball is arranged on the second target ball seat, characterized in that the method comprises the steps of testing the torsional performance of the continuum robot and the step of testing the stiffness performance of the continuum robot, wherein:

[0007] The steps to test the torsion resistance of a continuum robot include:

[0008] S1: Read the tension F of the drive cable when the continuum robot arm is in a tensioned state 1×n ;

[0009] S2: Obtain the position information of the first optical target ball and the second optical target ball before twisting, respectively, denoted as P 1 (x 1 ,y 1 , z 1 ) and P 2 (x 2 ,y 2 , z 2), and based on P 1 and P 2 Get the position vector of the first optical target ball and the second optical target ball before twisting

[0010] S3: Apply torque T to the continuum robot arm through the mechanical performance testing device 1 , causing the continuum robot arm to twist;

[0011] S4: Obtain the position information of the first optical target ball and the second optical target ball after twisting, respectively, and record them as P′ 1 (x′ 1 , y′ 1 , z′ 1 ) and P′ 2 (x′ 2 , y′ 2 , z′ 2 ), and based on P′ 1 and P′ 2 Obtain the position vector of the first optical target ball and the second optical target ball after twisting

[0012] S5: Based on position vector and Obtaining the torsion angle θ of the continuum robot arm to test the torsion resistance of the continuum robot arm;

[0013] The steps to test the stiffness performance of a continuum robot include:

[0014] S10: Read the tension F1 of the drive cable when the continuum robot arm is in a tensioned state ′×n ;

[0015] S20: Obtaining the first position information P of the first optical target ball before being pulled 10 (x 10 ,y 10 , z 10 );

[0016] S30: Apply a vertical force F' to the continuum robot arm through the mechanical performance testing device 1 , so that the first optical target sphere is displaced;

[0017] S40: Obtaining the second position information P of the first optical target ball after being pulled 20 (x 20 ,y 20 , z 20 );

[0018] S50: Based on the first position information P 10 and the second position information P 20 Obtaining a displacement value Δs of the first optical target sphere;

[0019] S60: according to the pulling force F′ required to generate the displacement value Δs 1 The size of the continuum robot is used to test the stiffness performance of the robot.

[0020] Preferably, in step S5, the torsion angle θ of the continuum robot arm is obtained by the following formula:

[0021]

[0022] in, Represents the position vector of the first optical target sphere and the second optical target sphere before twisting, Represents the position vector of the first optical target sphere and the second optical target sphere after twisting.

[0023] Preferably, in step S5, the torsion resistance of the continuum robot arm is tested based on the torsion angle θ by the following formula:

[0024]

[0025] Among them, Q represents the torsion resistance of the continuum manipulator, T 1 Indicates torque.

[0026] Preferably, in step S50, the displacement value Δs of the first optical target sphere is obtained by the following formula:

[0027]

[0028] Among them, (x 10 ,y 10 , z 10 ) represents the first position information of the first optical target ball before being pulled, (x 20 ,y 20 , z 20 ) represents the second position information of the second optical target sphere after being pulled.

[0029] Preferably, in step S60, the stiffness performance of the continuum robot arm is tested according to the displacement value Δs by the following formula:

[0030]

[0031] Among them, K represents the stiffness performance of the continuum manipulator, F′ 1 Indicates the pulling force required to produce displacement Δs.

[0032] The present disclosure also provides a device for testing the mechanical properties of a continuum robot, comprising:

[0033] A base, wherein a support platform is arranged on the base, and a first fixed pulley and a second fixed pulley are arranged at both ends of the support platform;

[0034] The device also includes a cable and a dynamometer, one end of the cable is connected to the target ball seat, and the other end of the cable is guided to the dynamometer via a first fixed pulley and a second fixed pulley.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. The continuum robot mechanical performance testing device proposed in the present disclosure can quantitatively test the torsional resistance and stiffness performance of the continuum robot.

[0037] 2. The continuum robot mechanical property testing device proposed in the present disclosure is based on a laser tracker and has high detection accuracy at the nanometer level.

[0038] 3. The continuum robot mechanical properties testing device proposed in the present disclosure is universal for continuum robots and has a simple implementation method. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A schematic diagram of the overall structure of a continuum robot provided by the present disclosure;

[0040] Figure 2 for Figure 1 Schematic diagram of the structure of the continuum robot arm;

[0041] Figure 3 A schematic diagram of a torsional performance test of a continuum robot arm provided with a first target ball seat and a second target ball seat;

[0042] Figure 4 The analysis results of the torsional performance test using the finite element method;

[0043] Figure 5 A schematic diagram of a stiffness performance test of a first target ball seat;

[0044] Figure 6 The analysis results of the stiffness performance test using the finite element method are shown below;

[0045] Figure 7 Schematic diagram of the device structure for testing the mechanical properties of the continuum robot;

[0046] The following are the descriptions of the reference numerals:

[0047] 1. Continuum robot; 2. Test device; 3. Laser tracker system; 4. Continuum manipulator; 5. Positioning target ball seat; 6. First target ball seat; 7. First optical target ball; 8. Support platform; 9-1. First fixed pulley; 9-2. Second fixed pulley; 10. Tension meter; 11. Second target ball seat; 12. Second optical target ball; 13. Drive cable; 14. End metal ring; 15. Start metal ring. DETAILED DESCRIPTION

[0048] The following will refer to the attached Figures 1 to 7 Specific embodiments of the present disclosure are described in detail. Although specific embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0049] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned throughout the specification and claims, "including" or "comprising" is an open term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present disclosure, but the description is based on the general principles of the specification and is not used to limit the scope of the present disclosure. The scope of protection of the present disclosure shall be determined by the attached claims.

[0050] To facilitate understanding of the embodiments of the present disclosure, further explanation will be given below using specific embodiments as examples in conjunction with the accompanying drawings, and each of the accompanying drawings does not constitute a limitation on the embodiments of the present disclosure.

[0051] In one embodiment, the present disclosure provides a method for testing the mechanical properties of a continuum robot, such as Figure 1 As shown, the continuum robot 1 includes Figure 2 The continuum robot arm 4 and the fixing member shown in the figure are fixed on the optical platform by the fixing member, and four positioning target ball seats 5 are arranged on the fixing member for positioning the coordinate system of the continuum robot arm; the continuum robot also includes a driving module and a pulley group, and the pulley group guides the driving cable 13 from the driving module to the continuum robot arm 4, so that the driving module can drive the continuum robot arm 4 to perform bending movement through the driving cable 13; the end of the continuum robot arm 4 is provided with a target ball seat, and the target ball seat is provided with an optical target ball, wherein, as shown in FIG. Figure 3 As shown, in the torsion resistance test, the end of the robot arm is provided with a first target ball seat 6 and a second target ball seat 11; Figure 5 As shown, in the stiffness performance test, a first target ball seat 6 is provided at the end of the robot arm; a first optical target ball 7 is provided on the first target ball seat 6, and a second optical target ball 12 is provided on the second target ball seat 11. It is characterized in that the method includes the steps of testing the torsion resistance of the continuum robot and the steps of testing the stiffness performance of the continuum robot, wherein:

[0052] The steps to test the torsion resistance of a continuum robot include:

[0053] S1: Read the tension F of the drive cable when the continuum robot arm is in a tensioned state 1×n , n represents the number of cables;

[0054] S2: Obtain the position information of the first optical target ball and the second optical target ball before twisting, respectively, denoted as P 1 (x 1 ,y 1 , z 1 ) and P 2 (x 2 ,y 2 , z 2 ), and based on P 1 and P 2 Get the position vector of the first optical target ball and the second optical target ball before twisting

[0055] S3: Apply torque T to the continuum robot arm through the mechanical performance testing device 1 , causing the continuum robot arm to twist;

[0056] S4: Obtain the position information of the first optical target ball and the second optical target ball after twisting, respectively, and record them as P′ 1 (x′ 1 , y′ 1 , z′ 1 ) and P′ 2 (x′ 2 , y′ 2 , z′ 2 ), and based on P′ 1 and P′ 2 Obtain the position vector of the first optical target ball and the second optical target ball after twisting

[0057] S5: Based on position vector and Obtaining the torsion angle θ of the continuum robot arm to test the torsion resistance of the continuum robot arm;

[0058] During the test, the continuum robot 1 needs to be placed horizontally first, and the drive cable 13 is adjusted by the drive module so that the continuum robot arm 4 is in a tensioned state. Then the tension on the drive cable 13 in the tensioned state is read by the force sensor. Secondly, two external forces of equal magnitude and opposite directions are applied to the continuum robot arm 4, one of which is vertically upward and acts on the first target ball seat 6 directly fixed on the continuum robot arm 4, and the other is vertically downward and acts on the second target ball seat connected to the first target ball seat 6, which is equivalent to applying a torque to the continuum robot arm. Based on the laser tracker system 3, the position information of the first optical target ball 7 installed on the first target ball seat 6 and the second optical target ball 12 installed on the second target ball seat 11 is obtained, and based on the position information before and after loading, the torsion angle θ of the continuum robot arm 4 can be solved, and then the torsion resistance of the continuum robot in the current tensioned state can be evaluated.

[0059] Specifically, the torsion angle under unit torque is used to evaluate the torsion resistance of the continuum manipulator, and the calculation formula is:

[0060]

[0061] Among them, Q represents the torsion resistance of the continuum manipulator, T 1 Indicates torque.

[0062] like Figure 4 As shown, in this embodiment, the finite element method is used to test the torsion resistance of the continuum robot composed of five metal rings, wherein a fixed support is applied to the end metal ring 14, and a torque is applied to the start metal ring 15, and the torque is 0.1N·m. The position information of the first optical target ball 7 before torsion is obtained by finite element analysis as P 1 (0, 0, 0), the position information after twisting is P′ 1 (0, 0, 0) (unit: mm), the position information of the second optical target sphere 12 before twisting is P 2 (6, 0, 0), the position information after twisting is P 2 (5.95135, 0, 0.77379) (unit: mm), L = 6 mm, the torsional performance is obtained from the above formula:

[0063]

[0064] The steps to test the stiffness performance of a continuum robot include:

[0065] S10: Read the tension F′ of the driving cable when the continuum robot arm 4 is in a tensioned state 1×n ;

[0066] S20: Obtaining the first position information P of the first optical target sphere 7 before being pulled 10 (x 10 ,y 10 , z 10 );

[0067] S30: Apply a vertical force F' to the continuum robot arm through the mechanical performance testing device 1 , so that the first optical target sphere 7 is displaced;

[0068] S40: Obtaining the second position information P of the first optical target sphere 7 after being pulled 20 (x 20 ,y 20 , z 20 );

[0069] S50: Based on the first position information P 10 and the second position information P 20 Obtaining a displacement value Δs of the first optical target sphere 7;

[0070] S60: according to the pulling force F′ required to generate the displacement value Δs 1 The size of the continuum robot is used to test the stiffness performance of the robot.

[0071] During the test, the continuum robot 1 needs to be placed horizontally first, and the drive cable 13 is adjusted through the drive module so that the continuum robot arm 4 is in a tensioned state. Then the tension on the drive cable 13 in the tensioned state is read by the force sensor. Secondly, a vertical upward external force is applied to the continuum robot arm 4, and the external force acts on the first target ball seat 6 fixed on the continuum robot arm 4. Based on the laser tracker system 3, the position information of the first optical target ball 7 installed on the first target ball seat 6 is obtained, and based on the position information before and after loading, the end displacement of the continuum robot arm 4 is solved, and then the stiffness performance of the continuum robot in the current tensioned state can be evaluated.

[0072] Specifically, the stiffness performance of the continuum manipulator can be calculated by the following formula:

[0073]

[0074] Among them, K represents the stiffness performance of the continuum manipulator, F′ 1 Indicates the pulling force required to produce displacement Δs.

[0075] like Figure 6As shown, in this embodiment, the torsion resistance test of the continuum robot arm composed of five metal rings is carried out using the finite element method, wherein a fixed support is applied to the end metal ring 14, and a tension is applied to the starting metal ring 15, the tension is 1N, and the first position information of the first optical target ball 7 before being pulled is P 10 (0, 0, 0) (unit: mm), the second position information after tension is P 20 (2.8032, 0, 0) (unit: mm), and its stiffness performance is 356.735 N / m according to the above formula.

[0076] The existing test method using an electronic torsion tester is usually suitable for testing the torsion mechanical properties of simple non-assembly parts such as cylindrical parts, but it is difficult to apply to complex continuum robots because the end of the continuum robot has a large drive system and is difficult to fix under the gripper for testing. The present method conveniently performs torsion tests on the continuum robot by positioning the optical target ball. In addition, compared with the existing quasi-static test method, the present invention introduces a laser tracker to detect position change information, which has better displacement measurement accuracy. Among them, the measurement accuracy of the laser tracker is 16μm+0.8μm / m.

[0077] In another embodiment, if Figure 7 As shown, the present disclosure also provides a device 2 for testing the mechanical properties of a continuum robot, the device comprising:

[0078] A base, on which a support platform 8 is disposed, and two ends of the support platform 8 are respectively provided with a first fixed pulley 9-1 and a second fixed pulley 9-2;

[0079] The device further comprises a cable and a dynamometer 10, one end of the cable is connected to the first target ball seat or the second target ball seat, and the other end of the cable is guided to the dynamometer 10 via the first fixed pulley 9-1 and the second fixed pulley 9-2.

[0080] The technical solutions provided by the present disclosure are described in detail above in combination with specific embodiments. Meanwhile, the description of the above embodiments is only used to help understand the core idea of ​​the present disclosure. For those skilled in the art, according to the idea of ​​the present disclosure, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be understood as limiting the present disclosure.

Claims

1. A method for testing the mechanical properties of a continuum robot, wherein the continuum robot comprises a continuum robot arm connected by a drive cable, a first target ball seat and a second target ball seat are arranged at the end of the continuum robot arm, a first optical target ball is arranged on the first target ball seat, and a second optical target ball is arranged on the second target ball seat, wherein: The method comprises the steps of testing the torsion resistance of the continuum robot and testing the stiffness performance of the continuum robot, wherein: The steps to test the torsion resistance of a continuum robot include: S1: Read the tension of the drive cable when the continuum robot arm is in a tensioned state ; S2: respectively obtain the position information of the first optical target ball and the second optical target ball before twisting, and record them as and , and based on and Get the position vector of the first optical target ball and the second optical target ball before twisting ; S3: Apply torque to the continuum robot arm through the mechanical properties test device , causing the continuum robot arm to twist; S4: Obtain the position information of the first optical target ball and the second optical target ball after twisting, respectively, and record them as and , and based on and Obtain the position vector of the first optical target ball and the second optical target ball after twisting ; S5: Based on position vector and Get the torsion angle of the continuum robot , to test the torsional performance of the continuum manipulator; The steps to test the stiffness performance of a continuum robot include: S10: Read the tension of the drive cable when the continuum robot arm is in tension ; S20: Acquiring the first position information of the first optical target ball before being pulled ; S30: Apply vertical force to the continuum robot arm through the mechanical performance testing device , so that the first optical target sphere is displaced; S40: Acquiring the second position information of the first optical target ball after being pulled ; S50: Based on the first location information and second location information Get the displacement value of the first optical target sphere ; S60: According to the generated displacement value Required pulling force The size of the continuum robot is used to test the stiffness performance of the robot.

2. The method according to claim 1, wherein: In step S5, the torsion angle of the continuum robot arm is obtained by the following formula: : ； in, Represents the position vector of the first optical target sphere and the second optical target sphere before twisting, Represents the position vector of the first optical target sphere and the second optical target sphere after twisting.

3. The method according to claim 1, wherein: In step S5, based on the torsion angle The torsional performance of the continuum manipulator is tested by the following formula: ； Among them, Q represents the torsion resistance of the continuum manipulator, Indicates torque.

4. The method according to claim 1, wherein: In step S50, the displacement value of the first optical target sphere is obtained by the following formula: : ； in, Indicates the first position information of the first optical target ball before being pulled. Indicates the second position information of the second optical target sphere after being pulled.

5. The method according to claim 1, wherein: In step S60, according to the displacement value The stiffness performance of the continuum manipulator is tested by the following formula: ； Where K represents the stiffness performance of the continuum manipulator, Indicates displacement The amount of pulling force required.

6. A device for implementing the method for testing the mechanical properties of a continuum robot according to claim 1, comprising: A base, wherein a support platform is arranged on the base, and a first fixed pulley and a second fixed pulley are arranged at both ends of the support platform; The device also includes a cable and a dynamometer, one end of the cable is connected to the target ball seat, and the other end of the cable is guided to the dynamometer via a first fixed pulley and a second fixed pulley.

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