Flexible screwing method and device for bolt

Abstract

The invention discloses a flexible screwing method and device for a bolt. The device comprises a controller, a screwing module, a visual positioning assembly and a torque feedback assembly, and real-time pose data of a bolt head are obtained through the visual positioning assembly; according to the real-time pose data, a locking assembly is called to be embedded into the bolt head, twisting operation is executed, and torque real-time data corresponding to the twisting operation is obtained through a torque feedback assembly; according to the torque real-time data and the compliance control strategy, a torque adjusting instruction is issued to a twisting adjusting assembly so as to adjust torque output of the twisting assembly; and skipping to execute the step of acquiring the real-time pose data of the bolt head through the visual positioning assembly until the twisting operation is finished. The automation level and the operation efficiency of operation are improved, and meanwhile, the risk of manual operation is greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of bolt rotation, and particularly to a compliant rotation method and rotation device for bolts. Background Art

[0002] With the acceleration of the industrialization process and the increasing demand for electricity, the construction and maintenance of key infrastructures such as substations have become particularly important. In these facilities, bolt connection, as a common mechanical connection method, the quality of its rotation is directly related to the stability and safety of the equipment. However, in special environments such as high-voltage electric fields and narrow spaces, traditional bolt rotation technologies face many challenges.

[0003] Traditional bolt rotation technologies mainly rely on manual or semi-automatic equipment for operation, and these methods have limitations in terms of accuracy, efficiency, and safety. Especially in high-voltage electric fields, manual operation is not only inefficient but also poses a great safety risk. During manual operation, arc discharge may be triggered due to accidental contact with high-voltage equipment, resulting in equipment damage or personal injury, and even serious safety accidents may occur. At the same time, these devices often lack sufficient compliance and adaptability and are difficult to cope with complex and changeable working environments. Summary of the Invention

[0004] The present invention provides a solution to the technical problem that traditional bolt rotation technologies mainly rely on manual or semi-automatic equipment for operation and have low compliance and adaptability in high-voltage electric fields or complex and changeable environments.

[0005] A compliant rotation device for bolts provided by the present invention includes a controller, a rotation module, a vision positioning component, and a torque feedback component;

[0006] The rotation module includes a locking component, a connecting component, and a rotation adjustment component connected in sequence, and is used to respond to the torque adjustment instruction issued by the controller through the rotation adjustment component, and adjust the output torque of the locking component through the connecting component;

[0007] The torque feedback component is sleeved on the connecting component and is used to collect the real-time torque data generated by the locking component during the rotation action in real time and upload it to the controller;

[0008] The vision positioning component is installed on the rotation adjustment component and is used to obtain the real-time pose data of the bolt head and upload it to the controller;

[0009] The controller is used to call the locking component to fit onto the bolt head according to the real-time pose data, and generate a torque adjustment instruction and issue it to the rotation adjustment component according to the real-time torque data and the compliant control strategy.

[0010] Optionally, it further includes a bidirectional sleeve and an operating rod;

[0011] The operating rod is connected to the twisting adjustment assembly through the bidirectional sleeve, and is used to provide a position that can be held.

[0012] Optionally, it further includes a robotic arm;

[0013] The operating rod is detachably connected to the power output end of the robotic arm, so as to move the twisting module through the robotic arm.

[0014] Optionally, the locking assembly includes a locking sleeve and a flexible connecting piece;

[0015] The locking sleeve is provided with an internal hexagonal structure matching the shape of the bolt head and is fixedly connected to the connecting assembly, and is used to fit with the outer edge of the bolt head;

[0016] The flexible connecting piece is sleeved on the connecting assembly and is used to absorb the axial force and / or lateral force generated by the twisting action.

[0017] Optionally, the connecting assembly includes a bidirectional connecting rod and a transmission fixing piece;

[0018] One end of the bidirectional connecting rod is connected to the locking sleeve, and the other end is fitted into the transmission fixing piece;

[0019] The transmission fixing piece is accommodated in the twisting adjustment assembly and is used to transmit the output power of the twisting adjustment assembly to the locking assembly along the bidirectional connecting rod.

[0020] Optionally, the twisting adjustment assembly includes a twisting sleeve, a power module and an elastic activity mechanism;

[0021] The power module is installed in the twisting sleeve, and the power output shaft is connected to the transmission fixing piece, and is used to respond to the torque adjustment instruction and adjust the output torque of the locking assembly;

[0022] The elastic activity mechanism is installed at the other end of the twisting sleeve and is used to provide a pre-tightening force and an activity angle to keep the locking assembly in continuous contact with the bolt head.

[0023] Optionally, the elastic activity mechanism includes an activity joint group, an adjustment spring and a spring fixing piece;

[0024] The adjustment spring is sleeved on the outside of the activity joint group, one end is connected to the outside of the twisting sleeve, and the other end is limited by the spring fixing piece;

[0025] The activity joint group includes at least two activity joints connected by pin joints to provide multiple activity angles for the twisting sleeve.

[0026] Optionally, the visual positioning component is a binocular camera, and the torque feedback component is a six-axis force sensor.

[0027] The present invention also provides a compliant screwing method for bolts, which is characterized in that it is applied to a controller in the compliant screwing device for bolts as described in any one of the above, and the method includes:

[0028] Obtaining real-time pose data of the bolt head through the visual positioning component;

[0029] Invoking the locking component to fit to the bolt head according to the real-time pose data and performing a screwing operation, and obtaining real-time torque data corresponding to the screwing operation through the torque feedback component;

[0030] Issuing a torque adjustment instruction to the screwing adjustment component according to the real-time torque data and the compliant control strategy to adjust the torque output of the screwing component;

[0031] Jumping to execute the step of obtaining the real-time pose data of the bolt head through the visual positioning component until the screwing operation ends.

[0032] Optionally, issuing a torque adjustment instruction to the screwing adjustment component according to the real-time torque data and the compliant control strategy includes:

[0033] Inputting the real-time torque data into an impedance control model to determine a position correction amount;

[0034] Correcting the current position by using the position correction amount to obtain a corrected position;

[0035] Determining a joint torque according to the corrected position and the current position, and issuing a torque adjustment instruction to the screwing adjustment component according to the joint torque;

[0036] The impedance control model is:

[0037]

[0038] Wherein, is the position correction amount, is the inertia matrix, is the damping matrix, is the stiffness matrix, is the real-time torque data.

[0039] It can be seen from the above technical solutions that the present invention has the following advantages:

[0040] The present invention provides a compliant rotation device and a rotation method for bolts. The device includes a controller, a rotation module, a visual positioning component, and a torque feedback component. The rotation module includes a locking component, a connection component, and a rotation adjustment component connected in sequence, and is used to respond to the torque adjustment instruction issued by the controller through the rotation adjustment component, and adjust the output torque of the locking component through the connection component. The torque feedback component is sleeved on the connection component and is used to collect the real-time torque data generated by the locking component during the rotation action in real time and upload it to the controller. The visual positioning component is installed on the rotation adjustment component and is used to obtain the real-time pose data of the bolt head and upload it to the controller. The controller is used to call the locking component to fit onto the bolt head according to the real-time pose data, and generate a torque adjustment instruction and send it to the rotation adjustment component according to the real-time torque data and the compliant control strategy. Through the collaborative work of the above components, efficient, precise, and safe bolt tightening operations are realized in a high-voltage electric field and a narrow space environment. The design of the present invention fully considers the particularity of the working environment. By integrating advanced sensors, actuators, and control algorithms, the automation level and working efficiency of the operation are improved, and at the same time, the risk of manual operation is greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0042] Figure 1 It is a schematic structural diagram of a compliant rotation device for bolts provided by an embodiment of the present invention;

[0043] Figure 2 It is a three-view drawing of a compliant rotation device for bolts provided by an embodiment of the present invention;

[0044] Figure 3 It is a schematic diagram of the installation position of a drain wire bolt in an embodiment of the present invention;

[0045] Figure 4 It is a working scene diagram of a drain wire disassembly and assembly robot provided by an embodiment of the present invention;

[0046] Figure 5 It is a connection schematic diagram of an operating rod connected to a robotic arm in an embodiment of the present invention;

[0047] Figure 6 It is a step flow chart of a compliant rotation method for bolts provided by an embodiment of the present invention.

[0048] Reference numerals: 1, rotation module; 2, vision positioning component; 3, torque feedback component; 11, locking component; 12, connection component; 13, rotation adjustment component; 4, bidirectional sleeve; 5, operating rod; 6, robotic arm; 111, locking sleeve; 112, flexible connecting piece; 121, bidirectional connecting rod; 122, transmission fixing piece; 131, rotation sleeve; 132, movable joint group; 133, adjusting spring. Detailed implementation manners

[0049] An embodiment of the present invention provides a compliant rotation method and device for bolts, which are used to solve the technical problems that traditional bolt rotation technologies mainly rely on manual or semi-automatic devices for operation, and have low compliance and adaptability in high-voltage electric fields or complex and changeable environments.

[0050] In order to make the invention objectives, features, and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0051] Please refer to Figure 1 and Figure 2 , Figure 1 which is a schematic structural diagram of a compliant rotation device for bolts provided by an embodiment of the present invention. Figure 2 which is a three-view drawing of a compliant rotation device for bolts provided by an embodiment of the present invention.

[0052] A compliant rotation device for bolts provided by the present invention includes a controller, a rotation module 1, a vision positioning component 2, and a torque feedback component 3;

[0053] The rotation module 1 includes a locking component 11, a connection component 12, and a rotation adjustment component 13 that are connected in sequence, and is used to respond to the torque adjustment instruction issued by the controller through the rotation adjustment component 13, and adjust the output torque of the locking component 11 through the connection component 12;

[0054] The torque feedback component 3 is sleeved on the connection component 12, and is used to collect the real-time torque data generated by the locking component 11 during the rotation action in real time and upload it to the controller;

[0055] The vision positioning component 2 is installed on the rotation adjustment component 13, and is used to obtain the real-time pose data of the bolt head and upload it to the controller;

[0056] A controller is configured to call the locking component 11 to fit onto the bolt head according to the real-time pose data, and generate a torque adjustment command based on the real-time torque data and the compliance control strategy, and send the command to the rotation adjustment component 13.

[0057] The rotation action refers to the action of tightening (increasing the tightness) or loosening (decreasing the tightness) a bolt.

[0058] In this embodiment, the compliant rotation of the bolt is achieved through modular design. Each component forms a closed-loop control system through mechanical connection and electrical signal interaction. Specifically, the compliant rotation device of the bolt may include a controller, a rotation module 1, a visual positioning component 2, and a torque feedback component 3. Among them, the controller, as the core signal processing part of the device, controls the position where the locking component 11 fits onto the bolt head according to the real-time pose data uploaded by the visual positioning component 2 to perform the rotation action. At the same time, after the torque feedback component 3 collects the real-time torque data, a torque adjustment command is generated in combination with the compliance control strategy and sent to the rotation adjustment component 13 to adjust the torque output. The rotation module 1 includes a locking component 11, a connection component 12, and a rotation adjustment component 13. The rotation adjustment component 13 responds to the torque adjustment command and transmits the power through the connection component 12 to adjust the output torque of the locking component 11. The visual positioning component 2 is installed on the outer wall of the rotation adjustment component 13 and communicates with the controller. Through its built-in camera and positioning functions, it can obtain the real-time pose data of the bolt head in real time, providing a data basis for the subsequent fitting of the locking component 11. The torque feedback component 3 is sleeved in the middle of the connection component 12 and is close to the locking component 11. When the locking component 11 performs the rotation action, it can collect the real-time torque data of the locking component 11 in real time and upload it to the controller. For example, the strain gauge force measurement principle can be adopted to monitor the axial forces and torque data in each axis of the three-dimensional coordinate system at a certain sampling frequency.

[0059] As Figure 3 shown, Figure 3 This is a schematic diagram of the installation position of the drain wire bolt in the embodiment of the present invention.

[0060] In this embodiment, after the drain wire is connected to the fitting, the drain wire clamp adopts a double-bolt symmetric rotation structure. When it is necessary to perform a rotation operation on the bolt after fitting the bolt to the nut, the visual positioning component 2 is started for this operation area, that is Figure 3Locate the position of the drainage wire clamp therein, identify the contour and position of the bolt head, mainly obtain the real-time pose data of the bolt head and upload it to the controller. The controller calls the locking component 11 to fit onto the bolt head. At the same time, through the camera calibration algorithm, convert the pixel coordinates into three-dimensional coordinates (X, Y, Z, θx, θy, θz) in the robot coordinate system to generate a rotation path. After starting the rotation operation, the torque feedback component 3 collects the real-time torque data generated by the rotation action of the locking component 11 in real time and uploads it to the controller. The controller calculates the position correction amount according to the real-time torque data combined with the compliant control strategy, generates a torque adjustment instruction and issues it to the rotation adjustment component 13. The output torque of the locking component 11 is adjusted through the connection component 12 until the rotation action is completed.

[0061] In addition, for the disassembly and assembly actions in the disassembly and assembly working conditions, the same can be achieved through the above method. The direction of its output torque is opposite to the rotation action, and the embodiments of the present invention do not limit this.

[0062] In this embodiment, through the integration of sensors, actuators and control algorithms, the real-time monitoring and precise control of the bolt rotation process are realized. This device can adapt to changing working environments, accurately identify the bolt position through the vision positioning system, and combine the torque feedback and compliant control strategies to ensure efficient and safe operation in complex environments. The rotation method combines vision positioning, torque feedback and compliant control strategies. The integration of these technologies enables the device to perform multi-directional actions and complete the whole process of disassembly and assembly of the drainage wire in a narrow space.

[0063] Optionally, the device further includes a two-way sleeve 4 and an operating rod 5;

[0064] The operating rod 5 is connected to the rotation adjustment component 13 through the two-way sleeve 4 to provide a position that can be held.

[0065] In the embodiment of the present invention, the operating rod 5 is connected to the rotation adjustment component 13 through the two-way sleeve 4 to provide a position that can be held for the user or for connecting other devices. In addition, the two-way sleeve 4 belongs to an auxiliary component, and different types, materials and lengths of operating rods 5 can be replaced to adapt to different working conditions. There are hole positions for connecting to the robotic arm 6 on the operating rod 5, and the device can be connected to the end of the robotic arm 6 through the connecting hole positions.

[0066] Further, the device further includes a robotic arm 6;

[0067] The operating rod 5 is detachably connected to the power output end of the robotic arm 6 to move the rotation module 1 through the robotic arm 6.

[0068] As Figure 4 shown, Figure 4 shows an operation scenario diagram of a drainage wire disassembly and assembly robot provided by the embodiment of the present invention.

[0069] In this embodiment, the operating rod 5 can be connected to the power output end of the robotic arm 6, and the end pose of the robotic arm 6 can be adjusted according to the real-time pose data through the communication connection between the controller and the robotic arm 6.

[0070] As Figure 5 shown, Figure 5 Fig. shows a schematic connection diagram of the operating rod 5 accessing the robotic arm 6 in an embodiment of the present invention.

[0071] In this embodiment, after the vision positioning component 2 is started, the Figure 4 substation drainage line clamp in is scanned to identify the bolt head features (such as hexagonal contour, central position). The pixel coordinates are converted into three-dimensional coordinates (X, Y, Z, θx, θy, θz) in the robot coordinate system through the camera calibration algorithm to generate a screwing path. If the bolt position deviation is detected (such as deviation > 0.5 mm), the controller calculates the position correction amount Δx through the impedance control model and drives the robotic arm 6 to adjust the end pose until the screwing action is completed.

[0072] Optionally, the locking assembly 11 includes a locking sleeve 111 and a flexible connecting piece 112;

[0073] The locking sleeve 111 is provided with an internal hexagonal structure matching the shape of the bolt head and is fixedly connected to the connecting assembly 12 for fitting with the outer edge of the bolt head;

[0074] The flexible connecting piece 112 is sleeved on the connecting assembly 12 for absorbing the axial force and / or lateral force generated by the screwing action.

[0075] In this embodiment, the locking sleeve 111 ensures that the bolt head can be firmly locked during the screwing process through the internal hexagonal structure to prevent slippage. At the same time, the flexible connecting piece 112 is sleeved on the connecting assembly 12 to absorb the axial force and / or lateral force generated by the screwing action, so as to reduce the impact on the bolt and this device and improve the smoothness of the screwing process.

[0076] Optionally, the connecting assembly 12 includes a bidirectional connecting rod 121 and a transmission fixing piece 122;

[0077] One end of the bidirectional connecting rod 121 is connected to the locking sleeve 111, and the other end is fitted into the transmission fixing piece 122;

[0078] The transmission fixing piece 122 is accommodated in the screwing adjustment assembly 13 for transmitting the output power of the screwing adjustment assembly 13 to the locking assembly 11 along the bidirectional connecting rod 121.

[0079] In this embodiment, the combination of the bidirectional connecting rod 121 and the transmission fixing member 122 forms the transmission component of the device, and its design allows torque to be transmitted in two directions, ensuring the effective transmission of the screwing force. At the same time, the transmission fixing member 122 is accommodated in the screwing sleeve 131 of the screwing adjustment assembly 13, and its central position is connected to the power output shaft of the power module to ensure the stable connection between the screwing adjustment assembly 13 and the bidirectional connecting rod 121.

[0080] Further, the screwing adjustment assembly 13 includes a screwing sleeve 131, a power module, and an elastic movable mechanism;

[0081] The power module is installed in the screwing sleeve 131, and the power output shaft is connected to the transmission fixing member 122, and is used to respond to the torque adjustment instruction and adjust the output torque of the locking assembly 11;

[0082] The elastic movable mechanism is installed at the other end of the screwing sleeve 131, and is used to provide a pre-tightening force and a movable angle to maintain the continuous contact between the locking assembly 11 and the bolt head.

[0083] In this embodiment, the screwing adjustment assembly 13 is the core component for realizing the bolt screwing function. Its power module can be an electric motor, etc., which is connected to the transmission fixing member 122 through the power output shaft, and then the screwing assembly is selected to realize the tightening or loosening of the bolt. Taking the screwing action as tightening, when the actual torque < the target value, a positive torque instruction is output to increase the speed and tighten; when the actual torque is close to the target value, it is switched to the low-speed mode (such as 0.1 r / s) to avoid overshoot. When the torque curve is stable within the range of ±5% of the target value and lasts for 2 seconds, it is determined that the tightening is completed, and at this time, the power output of the power module is stopped.

[0084] In addition, the elastic movable structure is installed at the other end of the screwing sleeve 131, that is, the section where the transmission fixing member 122 is not installed, so that the pre-tightening force of the spring can be adjusted according to the actual working requirements to maintain the contact with the bolt head. At the same time, the elastic movable member provides a certain movable angle, so that a certain angular deflection can be formed between the subsequent operating rod 5 and the screwing sleeve 131 to adapt to the screwing requirements at different angles in a complex environment.

[0085] Further, the elastic movable mechanism includes a movable joint group 132, an adjusting spring 133, and a spring fixing member;

[0086] The adjusting spring 133 is sleeved on the outside of the movable joint group 132, one end is connected to the outside of the screwing sleeve 131, and the other end is limited by the spring fixing member;

[0087] The movable joint group 132 includes at least two movable joints connected by pins to provide multiple movable angles for the screwing sleeve 131.

[0088] In this embodiment, the movable joint group 132 includes at least two movable joints connected by pins, and the pins can adjust the damping during joint movement to allow the operating rod 5 to rotate with a certain damping. The adjusting spring 133 is connected between the screwing sleeve 131 and the spring fixing member to ensure the stability of the pre-tightening force of the spring through the spring fixing member, and at the same time facilitate the installation and disassembly of the adjusting spring 133.

[0089] Optionally, the visual positioning component 2 is a binocular camera, and the torque feedback component 3 is a six-axis force sensor.

[0090] A binocular camera is an imaging system that simulates human binocular vision. It consists of two cameras (left camera and right camera) placed in parallel. By synchronously acquiring two-dimensional images of the same scene, it calculates the three-dimensional spatial information (depth, distance, position, etc.) of the object using the parallax principle. Its core function is to restore the three-dimensional structure of the scene from two-dimensional images.

[0091] A six-axis force sensor is a sensor that can simultaneously measure the force (Fx, Fy, Fz) and three-dimensional torque (Mx, My, Mz) in three-dimensional space, with a total of 6 degrees of freedom (3 force components + 3 torque components). Its core function is to convert the force on the mechanical structure into an electrical signal, which is used in scenarios such as robot contact force perception, precision assembly, and human-robot collaboration safety protection.

[0092] In an embodiment of the present invention, a compliant screwing device for bolts is provided, including a controller, a screwing module, a visual positioning component, and a torque feedback component; the screwing module includes a locking component, a connecting component, and a screwing adjustment component connected in sequence, and is used to respond to the torque adjustment instruction issued by the controller through the screwing adjustment component, and adjust the output torque of the locking component through the connecting component; the torque feedback component is sleeved on the connecting component and is used to collect the real-time torque data generated by the locking component during the screwing action in real time and upload it to the controller; the visual positioning component is installed on the screwing adjustment component and is used to obtain the real-time pose data of the bolt head and upload it to the controller; the controller is used to call the locking component to fit onto the bolt head according to the real-time pose data, and generate a torque adjustment instruction and send it to the screwing adjustment component according to the real-time torque data and the compliant control strategy. Through the collaborative work of the above components, efficient, precise, and safe bolt tightening operations are achieved in high-voltage electric field and narrow space environments. The design of the present invention fully considers the particularity of the operating environment, and improves the automation level and operating efficiency of the operation by integrating advanced sensors, actuators, and control algorithms, while greatly reducing the risk of manual operation.

[0093] Please refer to Figure 6 , Figure 6 which shows the step flow chart of a compliant screwing method for bolts provided by an embodiment of the present invention.

[0094] An embodiment of the present invention provides a compliant rotation method for bolts, which is applied to a controller in a compliant rotation device for bolts as described in any of the above embodiments. The method includes:

[0095] Step 601, obtaining real-time pose data of the bolt head through a vision positioning component;

[0096] The real-time pose data refers to data such as the real-time rotation position and three-dimensional position of the bolt head.

[0097] Step 602, calling a locking component to fit onto the bolt head according to the real-time pose data and performing a rotation operation, and obtaining real-time torque data corresponding to the rotation operation through a torque feedback component;

[0098] Step 603, issuing a torque adjustment instruction to a rotation adjustment component according to the real-time torque data and a compliant control strategy to adjust the torque output of the rotation component;

[0099] In this embodiment, during the execution of the robot trajectory in an unstructured environment, uncertainties in the dynamic parameters of the system body and deviations in the environmental geometric features will cause abnormal contact forces to be generated at the end effector. Therefore, the traditional Cartesian space position servo control mode has a large force tracking error under such working conditions. Real-time contact force feedback and force control technologies have become an indispensable part of the robot's contact operation in an unstructured environment. Even in a known environment, real-time contact force feedback and force control can significantly improve the intelligence and robustness of the robot system. Therefore, by combining the feedback of real-time torque data with a compliant control strategy, a torque adjustment instruction is generated and issued to the rotation adjustment component to adjust the torque output of the rotation component.

[0100] In an example of the present invention, step 603 may include the following sub-steps:

[0101] Inputting the real-time torque data into an impedance control model to determine a position correction amount;

[0102] Using the position correction amount to correct the current position to obtain a corrected position;

[0103] Determining joint torques according to the corrected position and the current position, and issuing a torque adjustment instruction to the rotation adjustment component according to the joint torques;

[0104] The impedance control model is:

[0105]

[0106] Among them, is the position correction amount, is the inertia matrix, is the damping matrix, is the stiffness matrix, It is real-time torque data.

[0107] In this embodiment, when the compliant twisting device is connected to the robotic arm and there is a difference between the measured real-time torque data and the desired contact force, the real-time torque data is input into the impedance control model to determine the position correction amount, and then the current position is corrected according to the position correction amount to obtain the corrected position. :

[0108]

[0109] Among them, is the desired position.

[0110] Then, the corresponding joint torque is determined according to the corrected position and the current position, and a torque adjustment instruction is sent to the twisting adjustment component according to the joint torque.

[0111] In addition, the joint torque can also be calculated in the following way:

[0112]

[0113] Among them, is the joint torque, is the acceleration vector of the desired position, is the virtual mass matrix, is the virtual damping matrix, is the velocity vector of the desired position, is the velocity vector of the actual position, is the virtual stiffness matrix, is the desired position, is the actual position vector, is the contact force vector in the real-time torque data.

[0114] Step 604: Jump to and execute the step of obtaining the real-time pose data of the bolt head through the vision positioning component until the twisting operation ends.

[0115] In another example of the present invention, when an external force acts on the end of the robot, the robot dynamics equation is expressed as:

[0116] (1)

[0117] Among them represents the displacements of the respective joints of the articulated robot, is the joint angular velocity, is the joint acceleration, is the robot inertia matrix. represents the robot centrifugal force and Coriolis force matrix; is the gravity vector of each link of the robot. is the driving force (moment) of the robot joint; is an n-dimensional robot Jacobian matrix that realizes the mutual conversion between the robot joint speed and the robot end speed, represents the dimension of the operation space; is the n-dimensional force / torque vector acting on the robot end. For forward dynamics, if is invertible, then we can obtain

[0118] (2)

[0119] where , , respectively represent the generalized coordinate vector, velocity, and acceleration. represents the inverse matrix of the inertia matrix in the joint space, represents the Coriolis force and centripetal force coupling matrix, represents the gravity matrix, represents the friction term, represents the force exerted by the robot end effector on the outside, represents the Jacobian matrix of the end effector, represents the joint driving force in the generalized coordinates.

[0120] To solve the dynamics in the Cartesian space, equation (1) is rewritten in the following form:

[0121] (3)

[0122] If the analytical Jacobian is used in the Cartesian space, then,

[0123] (4)

[0124] Taking the derivative of equation (4) gives:

[0125] (5)

[0126] Substituting equation (3) into equation (5) gives:

[0127] (6)

[0128] Rewriting (6) as:

[0129] (7)

[0130] Considering the control law in equation (7) as:

[0131] (8)

[0132] In the compliance control strategy of the present invention, torque-based impedance control is adopted. The name of impedance control comes from the relationship between voltage and current in a circuit, that is, assuming force is equivalent to voltage, velocity is equivalent to current, and mechanical impedance is equivalent to electrical impedance. The impedance control model of the robotic arm can be equivalent to a second-order mass-damping-spring system, the environmental dynamics model is represented by a spring system, and the contact model between the robotic arm and the environment can be divided into three stages: free movement, instant contact, and stable contact. And torque-based impedance control does not require a position controller, but directly outputs joint torques. Therefore, rewriting Equation (8) gives

[0133] (9)

[0134] Substituting (4) into Equation (7), we can get

[0135] (10)

[0136] Substituting the above equation into (2), we can get:

[0137] (11)

[0138] where is the virtual mass, is the parameter matrix given by the controller, is related to the specific task and expected characteristics, and has no direct relationship with the robot itself.

[0139] Let , we can get

[0140] (12)

[0141] Taking the Laplace transform of Equation (18), we can get:

[0142] (13)

[0143] If is a constant force, using the final value theorem for , we can get the final stable state:

[0144] (14)

[0145] Let

[0146] (15)

[0147] to obtain the torque-based impedance control model,

[0148] In this embodiment, a high-precision vision positioning system is used to accurately position the bolt. By using image processing technology, the position of the bolt can be quickly identified, providing accurate initial data for subsequent screwing operations. Subsequently, the torque feedback system monitors the torque changes in real time during the bolt screwing process to ensure that the torque can be adjusted in a timely manner during the screwing operation to meet specific process requirements. Based on these real-time feedback data, the compliant control strategy automatically adjusts the posture and force of the robotic arm to ensure the smoothness and accuracy of the bolt screwing process, thus avoiding over-tightening or under-tightening. Finally, the screwing device automatically adjusts the sleeve angle according to the data of the vision positioning system and the torque feedback system to achieve automatic screwing and loosening of the bolt, improving the operation efficiency and reliability.

[0149] Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working processes of the above-described devices and modules can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0150] In several embodiments provided by the present invention, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the modules is only a logical function division, and there may be other division methods in actual implementation. For example, multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces, and the indirect couplings or communication connections of the devices or modules can be in electrical, mechanical or other forms.

[0151] As mentioned above, the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A compliant rotation device for a bolt, characterized in that It includes a controller, a screwing module, a visual positioning component, and a torque feedback component; The screwing module includes a locking component, a connecting component, and a screwing adjustment component connected in sequence, and is used to respond to the torque adjustment instruction issued by the controller through the screwing adjustment component, and adjust the output torque of the locking component through the connecting component; The torque feedback component is sleeved on the connecting component and is used to collect the real-time torque data generated by the locking component during the screwing action in real time and upload it to the controller; The visual positioning component is installed on the screwing adjustment component and is used to obtain the real-time pose data of the bolt head and upload it to the controller; The controller is used to call the locking component to fit to the bolt head according to the real-time pose data, and generate a torque adjustment instruction and issue it to the screwing adjustment component according to the real-time torque data and the compliant control strategy.

2. The device according to claim 1, characterized in that, It further includes a bi-directional sleeve and an operating rod; The operating rod is connected to the screwing adjustment component through the bi-directional sleeve and is used to provide a position that can be held.

3. The device according to claim 2, wherein It further includes a robotic arm; The operating rod is detachably connected to the power output end of the robotic arm to move the screwing module through the robotic arm.

4. The device according to claim 1, characterized in that, The locking component includes a locking sleeve and a flexible connecting piece; The locking sleeve is provided with an internal hexagonal structure matching the shape of the bolt head and is fixedly connected to the connecting component, and is used to fit with the outer edge of the bolt head; The flexible connecting piece is sleeved on the connecting component and is used to absorb the axial force and / or lateral force generated by the screwing action.

5. The device according to claim 1, wherein The connecting component includes a bi-directional connecting rod and a transmission fixing piece; One end of the bi-directional connecting rod is connected to the locking sleeve, and the other end is fitted to the transmission fixing piece; The transmission fixing piece is accommodated in the screwing adjustment component and is used to transmit the output power of the screwing adjustment component to the locking component along the bi-directional connecting rod.

6. The device according to claim 5, characterized in that, The screwing adjustment component includes a screwing sleeve, a power module, and an elastic activity mechanism; The power module is installed in the screwing sleeve, and the power output shaft is connected to the transmission fixing piece, and is used to respond to the torque adjustment instruction and adjust the output torque of the locking component; The elastic activity mechanism is installed at the other end of the screwing sleeve and is used to provide a pre-tightening force and an activity angle to keep the locking component in continuous contact with the bolt head.

7. The device according to claim 6, characterized in that, The elastic activity mechanism includes an activity joint group, an adjustment spring, and a spring fixing piece; The adjustment spring is sleeved on the outside of the activity joint group, one end is connected to the outside of the screwing sleeve, and the other end is limited by the spring fixing piece; The activity joint group includes at least two activity joints connected by pins to provide multiple activity angles for the screwing sleeve.

8. The device according to claim 1, characterized in that, The visual positioning component is a binocular camera, and the torque feedback component is a six-axis force sensor.

9. A compliant screwing method for a bolt, characterized in that, For the controller in the compliant screwing device for bolts as described in any one of claims 1-8, the method includes: Obtaining the real-time pose data of the bolt head through the visual positioning component; Call the locking component according to the real-time pose data to fit into the bolt head and perform a twisting operation, and obtain the real-time torque data corresponding to the twisting operation through the torque feedback component; According to the real-time torque data and the compliance control strategy, issue a torque adjustment instruction to the twisting adjustment component to adjust the torque output of the twisting component; Jump to execute the step of obtaining the real-time pose data of the bolt head through the vision positioning component until the twisting operation ends.

10. The method according to claim 9, characterized in that, The issuing of the torque adjustment instruction to the twisting adjustment component according to the real-time torque data and the compliance control strategy includes: Input the real-time torque data into the impedance control model to determine the position correction amount; Use the position correction amount to correct the current position to obtain the corrected position; Determine the joint torque according to the corrected position and the current position, and issue a torque adjustment instruction to the twisting adjustment component according to the joint torque; The impedance control model is: Among them, is the position correction amount, is the inertia matrix, is the damping matrix, is the stiffness matrix, is the real-time data of the moment.

Images