A structural design method based on 360° rotating robot

Abstract

The present invention provides a structural design method based on a 360° rotating robot, which is applied to the 360° rotating robot. The structural design method includes: selecting and determining the arm length and joint motion range of the robot according to the workspace and load capacity; performing kinematic modeling; determining the driving scheme according to the relationship between the attribute constant of the robot and the driving torque of the robot joint; using SolidWorks to establish a three-dimensional model of the robot, and based on the dynamic simulation and verification of SolidWorks, making an overall design scheme for the robot; using SolidWorks finite element simulation analysis to perform lightweight design on the key components of the robot. The robot designed by the structural design method based on the 360° rotating robot of the present invention has an all-round rotation capability, can move and operate flexibly in any direction, realizes the comprehensive optimization of the robot structure and performance improvement, not only improves the work efficiency and reliability of the robot, but also reduces the production cost and energy consumption, and achieves the effect of high speed and high precision.

Description

Technical Field

[0001] The present invention relates to the technical field of robot structure design, and in particular to a structure design method based on a 360-degree rotating robot. Background Art

[0002] With the rapid development and progress of artificial intelligence technology, the intelligence of robots has become the ultimate goal of the development of modern robots. With the continuous improvement of the development speed of robots, the scope of application has also been continuously expanded, and many types of robots have emerged, such as operating robots, information robots, mobile robots, etc. The continuous development of robots has provided a lot of convenience for our lives, but also put forward more stringent requirements on the technologies involved. This requires continuous innovation and exploration of technical robots, and then adapt to the specific needs of the rapid development of robots. The emergence of SCARA robots has led to an unprecedented breakthrough in the development of the intelligent robot industry. Compared with previous robots, it is simpler to operate and more flexible. It quickly occupied a place in the market. So far, SCARA robots are still being developed and optimized.

[0003] However, the current traditional SCARA robots still have shortcomings in terms of speed, precision, weight, moment of inertia, rotation ability, system integration and reliability, and it is impossible to obtain high-speed, high-precision and lightweight robots, which needs further improvement. Summary of the invention

[0004] Based on this, in order to solve the problem that the current traditional SCARA robot still has deficiencies in speed, precision, weight, moment of inertia, rotation ability, system integration and reliability, and cannot obtain a high-speed, high-precision and lightweight robot, the purpose of the present invention is to provide a structural design method based on a 360° rotating robot, and its specific technical solution is as follows:

[0005] A structural design method based on a 360° rotating robot is applied to the 360° rotating robot. The 360° rotating robot comprises a base, an upper arm and a lower arm. One end of the upper arm is rotatably connected to the base via a first joint, and one end of the lower arm is rotatably connected to an end of the upper arm away from the first joint via a second joint. A first motor and a first reducer are arranged in the first joint, and a second motor and a second reducer are arranged in the second joint. The structural design method comprises:

[0006] Determine the robot's arm length and joint motion range based on the workspace and load capacity;

[0007] Perform kinematic modeling;

[0008] Determine the drive scheme selection based on the relationship between the robot's attribute constants and the robot's joint drive torque;

[0009] Use SolidWorks to build a 3D model of the robot, and make an overall design plan for the robot based on the dynamic simulation and verification of SolidWorks;

[0010] SolidWorks finite element simulation analysis is used to carry out lightweight design of key components of the robot.

[0011] Furthermore, the specific method for kinematic modeling is as follows: set the end of the upper arm to A, set the end of the lower arm to B, take the first joint as the coordinate origin O, establish a Cartesian coordinate system, the x-axis coordinate of B is the sum of the projections of vector OA and vector AB on the x-axis, and the y-axis coordinate of B is the sum of the projections of vector OA and vector AB on the y-axis. The kinematic equation is as follows:

[0012]

[0013] The kinematic equations can be rearranged to:

[0014]

[0015] Wherein, L1 is the arm length of the upper arm, and L2 is the arm length of the lower arm;

[0016] According to the modeling of the above kinematic inverse solution, given the data of L1 and L2, the kinematic equation gives the coordinates of the end B in the Cartesian coordinate system, the joint angle parameters of the branch chain are deduced, and the motion state of the upper arm and the lower arm is determined.

[0017] Furthermore, for the driving torque T required by the first joint and the second joint, the driving torque T is calculated when the first motor and the second motor run at the maximum angular velocity, and the calculation formula is as follows:

[0018] T=J* ;

[0019] From the parallel axis theorem we can get:

[0020] J=J G1 +m1L1 2 +J G2 +m2L2 2 ;

[0021] Among them J G1 is the moment of inertia of the boom about its center of gravity axis, J G2 is the moment of inertia of the forearm around its center of gravity axis, m1 is the weight of the boom, m2 is the weight of the forearm, L1 is the length of the boom, and L2 is the length of the forearm.

[0022] Furthermore, a flange sleeve is arranged in the first joint, and a bearing is arranged in the flange sleeve as a rotating support. The flange sleeve includes an outer flange and an inner flange. The outer flange is fixedly connected to the base, and the inner flange is connected to the upper arm.

[0023] Furthermore, after using SolidWorks to establish a three-dimensional model of the robot, the constraints are set, the SolidWorks motion plug-in is started, the motor drive parameters are set to the inner flange of the first joint, and 26 seconds is used as an acceleration and deceleration cycle. From the 1st second to the 11th second, the first joint is moved from 0 to the maximum angular velocity. After maintaining for 4 seconds, the angular velocity of the first joint is gradually reduced to 0 from the 15th second to the 25th second. After setting the motor parameters, the calculation and simulation are started, and the correctness of the selection of the core components of the robot is verified using the SolidWorks motion plug-in.

[0024] Furthermore, the specific steps of lightweight design of key robot components using SolidWorks finite element simulation analysis include:

[0025] Strength verification of robot joint seat;

[0026] Robot modal analysis: Analyze the first five natural frequencies of the robot;

[0027] Strength check and optimization design of the boom and forearm. Use the topology module in SolidWorks to perform topology optimization on the boom. Use the built-in quality assessment function in SolidWorks to compare the model after topology optimization with the model before topology optimization.

[0028] Robot whole machine strength check: set the whole machine mesh division for the robot.

[0029] Furthermore, the specific method for strength verification of the robot joint seat is as follows: perform static stress analysis on the external flange, first mesh the external flange, then apply a load of 1000N to the second joint, fix the bottom surface of the external flange, and then perform static stress analysis on the external flange.

[0030] Furthermore, the specific method for strength verification and optimization design of the upper arm and the lower arm is as follows: adopt a free meshing method, with tetrahedron as the main meshing method, fix the connecting surface of the flange in the first joint, apply a load of 1000N to the second joint of the upper arm, and perform static stress analysis.

[0031] Furthermore, the structural design method includes prototype manufacturing, and the accuracy of the robot is controlled by tolerance design.

[0032] Furthermore, the flange sleeve is designed by utilizing an interference fit method.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows: the structural design method based on the 360° rotating robot of the present invention determines the arm length and joint motion range of the robot according to the working space and load capacity, and the method can ensure that the robot operates efficiently on the specified working platform; through kinematic modeling, the position and posture of the robot at different joint angles can be accurately described, providing a solid theoretical basis for subsequent path planning and motion control; the driving scheme is determined according to the relationship between the robot's attribute constants and the joint driving torque, which can ensure that the robot can achieve efficient use of energy while meeting the work requirements, and the reasonable selection of the types and parameters of the motor and reducer can reduce energy consumption and improve the reliability and service life of the system; the three-dimensional modeling of the robot is carried out using three-dimensional modeling software such as SolidWorks, which can not only In order to intuitively display the appearance and structure of the robot, the overall design scheme of the robot can be verified and optimized through dynamic simulation and verification, which is helpful to discover and solve potential problems in the design stage and reduce subsequent production and debugging costs. The lightweight design of the key components of the robot through finite element simulation analysis can reduce the overall weight of the robot while ensuring the structural strength and rigidity, which can not only improve the robot's motion performance, but also reduce energy consumption and cost; the robot designed by the structural design method based on the 360° rotating robot of the present invention has all-round rotation ability, can move and operate flexibly in any direction, realizes the comprehensive optimization of the robot structure and performance improvement, not only improves the robot's work efficiency and reliability, but also reduces production costs and energy consumption, and achieves high speed and high precision effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention may be further understood from the following description in conjunction with the accompanying drawings, in which the components are not necessarily drawn to scale, but emphasis is placed on illustrating the principles of the embodiments, and in different views, the same reference numerals designate corresponding parts.

[0035] Figure 1 It is a schematic diagram of the overall structural design of a 360° rotating robot according to an embodiment of the present invention;

[0036] Figure 2 is a partial structural cross-sectional view of a 360° rotating robot according to an embodiment of the present invention;

[0037] Figure 3 It is a structural schematic diagram of a flange sleeve according to an embodiment of the present invention;

[0038] Figure 4 It is a flow chart of a structural design method based on a 360° rotating robot according to an embodiment of the present invention;

[0039] Figure 5is a schematic diagram of a robot establishing a Cartesian coordinate system according to an embodiment of the present invention;

[0040] Figure 6 is a data schematic diagram of the first joint angular velocity according to an embodiment of the present invention;

[0041] Figure 7 is a schematic diagram of motion simulation result data of a first joint according to an embodiment of the present invention;

[0042] Figure 8 is a data schematic diagram of the second joint angular velocity according to an embodiment of the present invention;

[0043] Fig. 9 is a schematic diagram of motion simulation result data of a second joint according to an embodiment of the present invention;

[0044] Fig.10 is a schematic diagram of mesh division results of the first joint outer flange according to an embodiment of the present invention;

[0045] Fig.11 is a schematic diagram of the meshing quality of a large arm according to an embodiment of the present invention;

[0046] Fig.12 It is a schematic diagram of the displacement results of the static stress analysis of the upper arm according to an embodiment of the present invention;

[0047] Fig.13 is a schematic diagram of stress distribution results of static stress analysis of a large arm according to an embodiment of the present invention;

[0048] Fig.14 is a schematic diagram of the result of topological optimization of a large arm according to an embodiment of the present invention;

[0049] Fig.15 It is a schematic diagram of the static stress analysis results of the 360° rotating robot described in one embodiment of the present invention.

[0050] Description of reference numerals:

[0051] 1. Base; 2. Upper arm; 3. Lower arm; 4. First joint; 5. Second joint; 6. First motor; 7. First reducer; 8. Second motor; 9. Second reducer; 10. Working platform; 11. Electric slip ring; 12. Flange sleeve; 13. Outer flange; 14. Inner flange. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with its embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not limit the adsorption scope of the present invention.

[0053] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0055] The “first” and “second” in the present invention do not represent specific quantities and orders, but are merely used to distinguish names.

[0056] like Figure 1-Figure 4 As shown, a structural design method based on a 360° rotating robot in one embodiment of the present invention is applied to the 360° rotating robot. The 360° rotating robot includes a base 1, an upper arm 2 and a lower arm 3. One end of the upper arm 2 is rotatably connected to the base 1 through a first joint 4, and one end of the lower arm 3 is rotatably connected to an end of the upper arm 2 away from the first joint 4 through a second joint 5. A first motor 6 and a first reducer 7 are provided in the first joint 4, and a second motor 8 and a second reducer 9 are provided in the second joint 5. The structural design method includes:

[0057] S1. Determine the robot's arm length and joint motion range based on the workspace and load capacity. In this embodiment, the robot's working platform 10 is an optical vibration isolation table of 1200mm×1200mm. The key technical parameters for selecting the robot's arm length include the workspace and load capacity. The workspace is not only related to the size of each rod and the rotation angle range of each joint, but also to the overall structure of the robot. The workspace must prevent both self-interference and singularity. The robot's arm span radius is determined by the workspace to be 600mm, the arm length of the upper arm 2 is 300mm, and the arm length of the lower arm 3 is 300mm. To meet the requirements of the workspace, the motion range of the first joint 4 is 360°, and the motion range of the second joint 5 is 360°.

[0058] S2. Perform kinematic modeling.

[0059] The robot in this embodiment is a two-link mechanism in series, and the first joint 4 and the second joint 5 are driven by rotational motion, so that the end of the robot reaches a specified position to complete a predetermined task, such as Figure 5 As shown, the specific method for kinematic modeling is as follows:

[0060] S21. Set the end of the upper arm 2 to A, and the end of the lower arm 3 to B. Take the first joint 4 as the coordinate origin O, and establish a Cartesian coordinate system. The x-axis coordinate of B is the sum of the projections of vector OA and vector AB on the x-axis. The y-axis coordinate of B is the sum of the projections of vector OA and vector AB on the y-axis. The kinematic equation is as follows:

[0061]

[0062] The kinematic equations can be rearranged to:

[0063] Among them, L1 is the arm length of the upper arm 2, and L2 is the arm length of the lower arm 3.

[0064] S22. Based on the modeling of the above kinematic inverse solution, given the data of L1 and L2, the coordinates of the end B in the Cartesian coordinate system are given by the geometric formula, the joint angle parameters of the branch chain are deduced, and the motion states of the upper arm 2 and the lower arm 3 are determined.

[0065] S3. Determine the drive scheme selection based on the relationship between the robot's attribute constants and the robot's joint drive torque.

[0066] In this embodiment, the robot needs to have a higher load-bearing capacity and a higher rigidity robot arm. According to the actual research working conditions and reference to the relevant parameter indicators of the SCARA robot, the core design indicators of the robot in this embodiment are shown in Table 1.

[0067] Table 1 Core indicators of robot design

[0068]

[0069] As a preferred embodiment of the present invention, it may also have the following additional technical features: for the driving torque T required by the first joint 4 and the second joint 5, the driving torque T is calculated when the first motor 6 and the second motor 8 run to the maximum angular velocity, and the calculation formula is as follows:

[0070] T=J* ;

[0071] From the parallel axis theorem we can get:

[0072] J=J G1 +m1L1 2 +J G2 +m2L2 2 ;

[0073] Among them J G1 is the moment of inertia of the arm 2 around its center of gravity axis, J G2 is the moment of inertia of the forearm 3 around its center of gravity axis, m1 is the weight of the upper arm 2, m2 is the weight of the forearm 3, L1 is the arm length of the upper arm 2, and L2 is the arm length of the forearm 3.

[0074] Because J G1 and J G2 The moments of inertia of the upper arm 2 and the lower arm 3 around their respective centroid axes are negligible. The initial forms of the upper arm 2 and the lower arm 3 are designed as entities with semicircles at both ends. The center moments of the two circles are the center moments of the joints. In this embodiment, the diameter of the semicircle is 136 mm, the height of the entity is 70 mm, and the volume is 3756537.5 mm 3 .

[0075] Specifically, in this embodiment, the primary material of the boom 2 is 45# steel, which has a density of 7850kg / m 3 ,The material of small arm 3 is 7075 aluminum alloy, and its density is 2800kg / m 3 , according to the density calculation formula: ρ = mV, we can solve: the mass of the upper arm 2 m1 = 29.5kg, the mass of the lower arm 3 m2 = 10.1kg, and substitute the mass of the upper arm 2 m1 and the mass of the lower arm 3 m2 into the formula J = J G1 +m1L1 2 +J G2 +m2L2 2 , and we get: J = 3.56 kg·m 2 ; Starting torque of the first joint 4: T=J* =22.35 N·m.

[0076] Because there will be a certain amount of mechanical loss due to the movement of parts during the actual driving process, and in order to improve the redundancy performance of the robot, assuming 30N·m, the safety factor is taken as 2, and the minimum torque output by the first reducer 7 is 60N·m. Taking the above factors into consideration, the first joint 4 uses the FB90-30-P0 planetary reducer produced by Li Ming in Taiwan, China, and its performance parameters are shown in Table 2. The second joint 5 is similar to the first joint 4, and the time required for the arm 3 to start to the maximum angular velocity is the same, and the safety factor is 2. The second reducer 9 finally chooses the SB90-30-P0 planetary reducer produced by Li Ming in Taiwan, China, and its performance parameters are shown in Table 3.

[0077] Table 2 FB90-30-P0 planetary reducer performance parameters

[0078]

[0079] Table 3 SB90-30-P0 planetary reducer performance parameters

[0080]

[0081] The motor for the first joint 4 is the Yaskawa SGM7A-10AFA61 AC servo motor, and the motor for the second joint 5 is the Yaskawa SGM7A-08AFA61 AC servo motor. The performance parameters are shown in Table 4.

[0082] Table 4 SGM7A AC servo motor performance parameters

[0083]

[0084] As a preferred embodiment of the present invention, it may also have the following additional technical features: in order to realize the turnover of the first joint 4 and improve the space utilization, the first joint 4 reducer and the first joint 4 motor are placed in the base, and in order to improve the joint stiffness, a flange sleeve 12 is provided in the first joint 4, and a bearing is provided in the flange sleeve 12 as a rotating support, and the flange sleeve 12 includes an outer flange 13 and an inner flange 14, the outer flange 13 is fixedly connected to the base 1, and the inner flange 14 is connected to the upper arm 2. The axial load and radial load are mainly carried by the intermediate bearing, and the bearing uses the Japanese NSK6012-VV bearing with a rated dynamic load Cr of 29.5KN, and adopts a double bearing design to provide a more stable support for the robot arm. Similarly, in this embodiment, the second joint 5 is provided with the flange sleeve 12 used for the first joint 4 to connect the upper arm 2 and the lower arm 3.

[0085] In addition, in this embodiment, the first motor 6 and the second motor 8 use Yaskawa SGM7A series AC servo motors, which have high precision, fast response, and high torque, and are widely used in the robotics industry; since the upper arm 2 and the lower arm 3 in this embodiment require a high stiffness, a planetary reducer is set in the first joint 4 and the second joint 5.

[0086] In order to transmit the power of the output shaft of the reducer to the connecting flange, a locking sleeve is used to connect the flange and transmit the output torque of the reducer. The working principle of the locking sleeve is to tighten the high-strength bolts between the inner ring and the shaft to produce pressure and friction between the containing surfaces to achieve load transmission. It is a keyless connection device suitable for high-load occasions, especially for alternating torque. It has high centering accuracy, convenient installation and disassembly, high strength, stable and reliable connection, and can ensure that the equipment is not damaged when overloaded. EUX18 locking sleeves produced by China Yiheda are selected at the first joint 4 of the big arm 2, and EUX18 locking sleeves produced by China Yiheda are also selected at the second joint 5 of the small arm 3. The maximum allowable torque of this type of locking sleeve is 290N·m, which meets the working characteristics of the robot at high speed and heavy load.

[0087] In order to realize the rotation of the first joint 4 and the second joint 5, the electrical wiring problem of the second motor 8 needs to be solved. An electric slip ring 11 is required to realize the electrical connection between the rotating body and the fixed structure. This embodiment selects the Yaskawa servo motor special slip ring produced by China Moflun, model MSE2025-01-S06-VC. Each group of motors has two cables in and out, namely a power cable (4 cores × 10A) and an encoder control cable (6 cores with shielding), with a rated voltage of 0-440VAC / VDC and an output torque of 0.3N·m.

[0088] S4. Use SolidWorks to build a 3D model of the robot, and make an overall design plan for the robot based on the dynamic simulation and verification of SolidWorks;

[0089] The specific steps are as follows, but not limited to:

[0090] S41. Build an assembly and use SolidWorks to build a 3D model of the robot;

[0091] S42, set up constraints;

[0092] S43, start the SolidWorks motion plug-in;

[0093] S44, setting the motor drive parameters to the inner flange 14 of the first joint 4, with 26 seconds as an acceleration and deceleration cycle, from the 1st second to the 11th second, the first joint 4 moves from 0 to the maximum angular velocity, and after maintaining for 4 seconds, the angular velocity of the first joint 4 is gradually reduced to 0 from the 15th second to the 25th second;

[0094] S45. After setting the motor parameters, start the calculation simulation and use the SolidWorks motion plug-in to verify the correctness of the selection of the robot's core components.

[0095] S46, analysis results. In this embodiment, the data curve of the angular velocity of the first joint 4 is Figure 6 As shown in the figure, after setting the motor parameters, the simulation is started. The results are as follows Figure 7 As shown in the figure, the maximum starting torque is 25.6N·m, which is close to the above calculation result.

[0096] Similarly, in this embodiment, using the above method, the motion simulation result of the driving motor of the second joint 5 is as follows: Figure 8-Figure 9As shown, the maximum starting torque is 3.7 N·m, and the second motor 8 and the second reducer 9 of the second joint 5 meet the design requirements. In summary, the motion plug-in of SolidWorks is used to verify the feasibility of the above overall design. The maximum starting torque is within the allowable torque range of the reducer and the motor, which verifies the correctness of the selection of the core components of the robot and meets the design requirements.

[0097] S5. Use SolidWorks finite element simulation analysis to perform lightweight design on key components such as the robot (flange sleeve 12, upper arm 2, and lower arm 3). Use the topology module in SolidWorks to perform topological optimization on upper arm 2. Use the built-in quality assessment function of SolidWorks to compare the upper arm 2 model after topological optimization with the model before topological optimization.

[0098] The robot's upper arm 2, base, and joint flange are made of 45# steel; in order to reduce the mass of the forearm 3 and ensure the strength and rigidity of the forearm 3 and improve the movement performance of the forearm 3, the forearm 3 is made of 7075 aluminum alloy.

[0099] The specific steps in S5 include, but are not limited to, the following:

[0100] S51. Strength check of robot joint seat.

[0101] Static stress analysis is performed on the external flange 13. The external flange 13 is first meshed. The results are as follows: Fig.10 As shown in the figure, the Jacobian ratio is a commonly used parameter to evaluate the quality of the mesh. It is often used to evaluate the elements with mid-nodes. Fig.10 It can be obtained that the Jacobian ratio of the bearing seat mesh division does not exceed 16, and the mesh division quality is good. Then, a load of 1000N is applied to the second joint 5, the bottom surface of the outer flange 13 is fixed, and then a static stress analysis is performed on the outer flange 13. From the analysis results, it can be obtained that the joint outer flange 13 does not have excessive displacement deformation, the stress is uniform and far less than the allowable stress, and the strength requirements are met.

[0102] S52. Robot modal analysis: Analyze the first five natural frequencies of the robot.

[0103] In this embodiment, the fifth-order natural frequency of the first five natural frequencies of the robot is analyzed and shown in Table 5 below. By analyzing the fifth-order natural frequency, it can be obtained that the SCARA robot itself will not cause resonance, and the overall vibration performance of the robot is good, but the fixed installation should avoid external high-frequency vibration sources.

[0104] Table 5

[0105]

[0106] In Cartesian coordinate system, the first to fifth order modal vibration shapes of SCARA robot are described as follows:

[0107] (1) The first-order vibration mode is the bending vibration of the small arm 3 and the large arm 2 along the X-axis;

[0108] (2) The second-order vibration mode is characterized by torsional swing of the small arm 3 and the large arm 2 along the Z axis;

[0109] (3) The third-order vibration mode is manifested as bending vibration of the lower arm 3 and the upper arm 2 along the second joint 5X axis;

[0110] (4) The fourth-order vibration mode is manifested as the torsional swing of the lower arm 3 and the upper arm 2 along the Z axis of the second joint 5;

[0111] (5) The fifth-order vibration mode is manifested as the torsional swing of the lower arm 3 and the upper arm 2 along the Y-axis.

[0112] S53, strength verification and optimization design of upper arm 2 and lower arm 3.

[0113] The free meshing method is adopted, the meshing is mainly based on tetrahedron, the connection surface of the flange 14 in the first joint 4 is fixed, and a load of 1000N is applied to the second joint 5 of the upper arm 2 to perform static stress analysis. Fig.11 As shown, it is a schematic diagram of the overall meshing quality of the boom 2 in this embodiment. The overall meshing quality of the boom 2 is good. The connection surface of the flange 14 in the first joint 4 is fixed, and a load of 1000N is applied to the second joint 5 of the boom 2. Static analysis is performed, and the displacement results are shown as follows: Fig.12 The stress distribution results are shown in Fig.13 As shown. The maximum deformation of the boom 2 under the maximum static load is 0.023mm, which occurs at the second joint 5 at the end of the boom 2. The maximum yield stress of the boom 2 is 530MPa. Under this load, the maximum stress is 5.9MPa, and it will not yield. Since the boom 2 is an important component connecting the forearm 3 and the base, the boom 2 not only bears the effects of the forearm 3, the end actuator, and the load, but also bears the torque of the motor. The quality of its mechanical properties will indirectly affect the positioning accuracy of the end working axis through the forearm 3. At the same time, the excessive weight of the boom 2 will also cause start-stop shocks and affect the performance of the entire machine. The topology module in SolidWorks is used to perform topological optimization on the boom 2. In order to ensure sufficient strength and stiffness, the weight reduction target is set to 30%. The results are shown in the figure. Fig.14 As shown, in other embodiments, in order to ensure a certain strength, a reinforcing rib can also be designed in the middle. Through the built-in quality assessment function of SolidWorks, the model of the boom 2 after topology optimization is compared with the model before topology optimization. The specific changes of the mass and moment of inertia of the boom 2 before and after topology optimization are shown in Table 6.

[0114] Table 6

[0115]

[0116] It can be seen from the table that after topology optimization, the mass of arm 2 is reduced by 7.879 kg, a year-on-year decrease of 37.3%; the moment of inertia is reduced by 0.446 kg· m², a year-on-year decrease of 49.2%.

[0117] Similarly, the structure of the forearm 3 is optimized using the above method. The specific changes of the mass and moment of inertia of the forearm 3 before and after the topological optimization are shown in Table 7.

[0118] Table 7

[0119]

[0120] After optimization, the mass of forearm 3 was reduced by 2.704kg, and the mass decreased by 27.8%; the moment of inertia was reduced by 0.123kg, and the moment of inertia decreased by 28.4%.

[0121] S54, robot whole machine strength check: set the whole machine grid division for the robot;

[0122] Specifically, in this embodiment, the robot is set to have a whole machine grid. Since the deformation of each joint and component in actual work will accumulate at the end of the forearm 3, a load of 250N is applied to it. The maximum Jacobian point number of the static stress analysis of the robot is 5.4, which meets the accuracy requirements.

[0123] From the analysis, the results are as follows Fig.15 As shown, except for the large displacement of the forearm 3, the upper arm 2 and the base maintain a small displacement deformation, and the maximum deformation of the flange at the end of the forearm 3 is 0.093mm. Therefore, the robot structure designed in this embodiment has high rigidity and meets the strength requirements of the design working conditions.

[0124] As a preferred embodiment of the present invention, it may also have the following additional technical features: the structural design method includes S6, prototype production, the accuracy of the robot is controlled by tolerance design, and the feasibility of the method is verified to a certain extent by making a prototype.

[0125] In method S6, the tolerance design method includes S61, designing the flange sleeve 12 by using the interference fit method. In this embodiment, the bearing model of the flange sleeve 12 of the upper arm 2 joint is 6012-VV, the outer diameter is 95mm, and the size of the inner hole of the outer flange 13 and the bearing is designed. The base shaft system is used, and the fitting tolerance is designed to be P7 / h6. The maximum interference of the hole is -0.002, and the minimum interference is -0.059.

[0126] In this embodiment, according to the relevant design indicators of the robot, the motor, reducer and other core components of the upper arm 2 and the lower arm 3 are selected, and the robot three-dimensional model is established using Solid Works to complete the overall design. The feasibility of the motor and reducer selection is simulated and verified from the perspective of dynamics using the Motion plug-in of Solid Works. After verifying the feasibility of the drive scheme, the overall structure is designed, the structure of the remaining components is determined, and the overall design is completed. In order to make the robot lightweight, the finite element analysis plug-in of Solid Works is used to perform static stress analysis and topological optimization on the upper arm 2 and the lower arm 3, and complete the overall weight reduction, so that the overall moment of inertia is reduced, so that the robot can move at high speed. Finally, the prototype is made, and the accuracy of the robot is controlled by tolerance design.

[0127] In the description of the above embodiments, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, "several" and "multiple" mean more than one, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" and "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0128] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction between the combinations of these technical features, they should be considered to be within the scope recorded in this specification.

[0129] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A structural design method based on a 360° rotating robot, applied to a 360° rotating robot, the 360° rotating robot comprising a base, an upper arm and a lower arm, one end of the upper arm being rotatably connected to the base via a first joint, one end of the lower arm being rotatably connected to an end of the upper arm away from the first joint via a second joint, a first motor and a first reducer being arranged in the first joint, a second motor and a second reducer being arranged in the second joint, a flange sleeve being arranged in the first joint, a bearing being arranged in the flange sleeve as a rotating support, the flange sleeve comprising an outer flange and an inner flange, the outer flange being fixedly connected to the base, the inner flange being connected to the upper arm, characterized in that, The structural design method comprises: Determine the robot's arm length and joint motion range based on the workspace and load capacity; Kinematic modeling is performed as follows: set the end of the upper arm to A, set the end of the lower arm to B, take the first joint as the coordinate origin O, establish a Cartesian coordinate system, the x-axis coordinate of B is the sum of the projections of vector OA and vector AB on the x-axis, and the y-axis coordinate of B is the sum of the projections of vector OA and vector AB on the y-axis. The kinematic equation is as follows: The kinematic equations can be rearranged to: Wherein, L1 is the arm length of the upper arm, and L2 is the arm length of the lower arm; According to the modeling of the above kinematic inverse solution, given the data of L1 and L2, the kinematic equation gives the coordinates of the end B in the Cartesian coordinate system, and the joint angle parameters of the branch chain are deduced to determine the motion state of the upper arm and the lower arm; Determine the drive scheme selection according to the relationship between the robot's attribute constant and the robot joint driving torque; for the driving torque T required for the first joint and the second joint, the first motor and the second motor are operated to the maximum angular velocity When calculating the driving torque T, the calculation formula is as follows: T=J* ; From the parallel axis theorem we can get: J=J G1 +m1L1 2 +J G2 +m2L2 2 ; Among them J G1 is the moment of inertia of the boom about its center of gravity axis, J G2 is the moment of inertia of the forearm around its center of gravity axis, m1 is the weight of the boom, m2 is the weight of the forearm, L1 is the length of the boom, and L2 is the length of the forearm; Use SolidWorks to build a 3D model of the robot, and make an overall design plan for the robot based on the dynamic simulation and verification of SolidWorks; Use SolidWorks finite element simulation analysis to perform lightweight design on key components of the robot; the specific steps include: Strength verification of robot joint seat; Robot modal analysis: Analyze the first five natural frequencies of the robot; Strength check and optimization design of the boom and forearm. Use the topology module in SolidWorks to perform topology optimization on the boom. Use the built-in quality assessment function in SolidWorks to compare the model after topology optimization with the model before topology optimization. Robot whole machine strength check: set the whole machine mesh division for the robot.

2. The method according to claim 1, characterized in that After using SolidWorks to build the robot's three-dimensional model, set the constraints, start the SolidWorks motion plug-in, set the motor drive parameters to the inner flange of the first joint, use 26 seconds as an acceleration and deceleration cycle, and make the first joint move from 0 to the maximum angular velocity from the 1st second to the 11th second. After maintaining for 4 seconds, the angular velocity of the first joint is gradually reduced to 0 from the 15th second to the 25th second. After setting the motor parameters, start the calculation and simulation, and use the SolidWorks motion plug-in to verify the correctness of the selection of the robot's core components.

3. The method according to claim 1, characterized in that The specific method for strength verification of the robot joint seat is as follows: static stress analysis is performed on the external flange, the external flange is first meshed, a load of 1000N is applied to the second joint, the bottom surface of the external flange is fixed, and then static stress analysis is performed on the external flange.

4. The method according to claim 1, characterized in that: The specific method for strength verification and optimization design of the upper arm and the lower arm is as follows: adopt a free meshing method, meshing mainly based on tetrahedrons, fix the connecting surface of the flange in the first joint, apply a load of 1000N to the second joint of the upper arm, and perform static stress analysis.

5. The method according to claim 1, characterized in that The structural design method includes prototype manufacturing and controlling the accuracy of the robot through tolerance design.

6. The method according to claim 5, characterized in that The flange sleeve is designed using the interference fit method.

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