Intelligent control upper pressing and lower jacking positioning pin auxiliary device and method

Abstract

The present invention discloses an intelligent control upper pressing and lower jacking positioning pin auxiliary device and method, which relates to the field of automated assembly, including: a trajectory construction module for constructing a collision-free trajectory through pose deviation after grasping a workpiece in the rough positioning area; a deviation analysis module for triggering microscopic deviation analysis to output a trajectory compensation action and a positioning pin compensation action after transferring the workpiece into the vision working area; a positioning pin extension module for pre-extending the positioning pin on the fixture base by using the positioning pin compensation action during the process of clamping the workpiece and moving it to the force sense guiding area; a pressure parameter acquisition module for activating a force sensor to acquire the fitting pressure parameter after the workpiece is pre-fitted with the positioning pin; an auxiliary assembly module for performing three-force closed-loop optimization based on the fitting pressure parameter, outputting three-force dynamic control parameters, and performing fixture-assisted assembly of the workpiece. It solves the technical problem of low assembly accuracy existing in the existing fixture-assisted assembly of workpieces and achieves the technical effect of improving the assembly accuracy.

Description

Technical Field

[0001] The present application relates to the field of automated assembly, and in particular to an intelligently controlled upward-pressing and downward-pushing positioning pin auxiliary device and method. Background Art

[0002] In the field of modern industrial automated assembly, high-precision and high-efficiency jig-assisted assembly of workpieces is crucial to improving product quality and production efficiency. At present, the traditional positioning pin-assisted assembly method based on preset trajectory and simple force feedback is mainly used to solve the problem of jig-assisted assembly of workpieces. That is, the motion trajectory of the robot arm is planned first, and the force in the assembly process is sensed through simple force feedback to realize the assembly of the positioning pin and the workpiece. Since this method does not fully consider the collision risk during the movement of the robot arm, the planned trajectory may collide with the surrounding environment in actual operation, affecting the safety and efficiency of assembly; at the same time, simple force feedback is difficult to accurately obtain the microscopic deviation between the workpiece and the positioning pin, resulting in low assembly accuracy and unable to meet the increasingly high assembly requirements.

[0003] In the current related technologies, workpiece fixture-assisted assembly has the technical problem of low assembly accuracy. Summary of the invention

[0004] The present application provides an intelligently controlled upper-pressure and lower-lift positioning pin auxiliary device and method. After a robotic arm grabs the target workpiece in the rough positioning area, it constructs a collision-free trajectory through posture deviation analysis, transfers it to the visual working area, triggers micro-deviation analysis, outputs the trajectory and positioning pin compensation action, and drives the robotic arm to the force guidance area according to the corrected trajectory. The electric positioning pin is simultaneously pre-extended using the positioning pin compensation action. After the robotic arm and the positioning pin are pre-engaged, the engagement pressure parameters are collected, and the three-force closed-loop optimization is performed based on the parameters. The dynamic control parameters are output to assist the upper pressure mechanism, the lower lift structure and the electric positioning pin in linkage displacement, and complete the technical means such as fixture-assisted assembly, thereby achieving the technical effect of improving assembly accuracy.

[0005] The present application provides an intelligent control upper pressing and lower jacking positioning pin auxiliary device, including: a trajectory construction module, configured to construct a collision-free trajectory through pose deviation analysis after the robotic arm grabs a target workpiece in the rough positioning area; a deviation analysis module, configured to trigger microscopic deviation analysis after driving the robotic arm to transfer the target workpiece into the vision working area by using the collision-free trajectory, and output a trajectory compensation action and a positioning pin compensation action; a positioning pin extension module, configured to synchronously perform pre-extension of K electric positioning pins on the fixture base by using the positioning pin compensation action during the process of driving the robotic arm to clamp the target workpiece to the force sensing guiding area by using the collision-free trajectory corrected by the trajectory compensation action; a pressure parameter acquisition module, configured to activate a force sensor to acquire fitting pressure parameters after the robotic arm clamps the target workpiece into the force sensing guiding area and pre-fits with the K electric positioning pins; an auxiliary assembly module, configured to perform three-force closed-loop optimization according to the fitting pressure parameters, output three-force dynamic control parameters, and assist the linkage displacement of the upper pressing mechanism, the lower jacking structure and the K electric positioning pins to perform fixture-assisted assembly of the target workpiece.

[0006] In a possible implementation manner, the trajectory construction module includes: a macroscopic position point cloud data acquisition module, configured to trigger a line laser scanner to acquire macroscopic position point cloud data according to the grasping behavior of the robotic arm in the rough positioning area, where the macroscopic position point cloud data includes H groups of non-coplanar feature points of the workpiece and positioning pin point clouds; a rough positioning analysis module, configured to perform rough positioning analysis according to the macroscopic position point cloud data and output a 6-degree-of-freedom pose deviation; a collision-free trajectory construction module, configured to construct the collision-free trajectory according to the 6-degree-of-freedom pose deviation and then start the robotic arm to clamp and displace the workpiece.

[0007] In a possible implementation manner, the rough positioning analysis module includes: a workpiece CAD model calling module, configured to locally call the workpiece CAD model according to the workpiece ID of the target workpiece; a 6-degree-of-freedom pose deviation calculation module, configured to register the macroscopic position point cloud with the workpiece CAD model through the ICP algorithm and calculate the 6-degree-of-freedom pose deviation of the target workpiece relative to the fixture, where the 6-degree-of-freedom pose deviation is composed of a translation component and a rotation component.

[0008] In a possible implementation, the deviation analysis module includes: an image acquisition module, configured to synchronously activate a main-view camera and an auxiliary-view camera after the target workpiece enters the vision working area, and acquire a workpiece image and a positioning pin image; a feature matching module, configured to perform edge detection and feature matching on the workpiece image and the positioning pin image respectively, and identify the spatial positions of K target positioning holes on the target workpiece and the spatial positions of W electric positioning pins on the fixture, where W is a positive integer greater than K; a neighboring positioning pin matching module, configured to perform neighboring positioning pin matching for the K target positioning holes according to the spatial positions of the K positioning holes and the spatial positions of the W positioning pins, and obtain K hole-pin matching groups; a 6-degree-of-freedom micro deviation calculation module, configured to extract the K electric positioning pins from the K hole-pin matching groups, and calculate and output a 6-degree-of-freedom micro deviation according to the spatial positions of the K positioning holes and the spatial positions of the K electric positioning pins of the K electric positioning pins; an associated compensation and correction module, configured to perform associated compensation and correction according to the 6-degree-of-freedom micro deviation, and output the trajectory compensation action and the positioning pin compensation action.

[0009] In a possible implementation, the associated compensation and correction module includes: a 6-degree-of-freedom micro deviation decomposition module, configured to decompose the 6-degree-of-freedom micro deviation to obtain a translation deviation and a rotation deviation; a fitting end correction amount calculation module, configured to calculate a fitting end correction amount of the robotic arm according to the translation deviation; a gripping pose correction amount calculation module, configured to calculate a gripping pose correction amount of the robotic arm according to the rotation deviation, where the fitting end correction amount and the gripping pose correction amount constitute the trajectory compensation action; a positioning pin compensation calculation module, configured to perform positioning pin compensation calculation after correcting the 6-degree-of-freedom micro deviation according to the trajectory compensation action, and obtain the positioning pin compensation action.

[0010] In a possible implementation, the positioning pin compensation calculation module includes: a 6-degree-of-freedom residual deviation output module, configured to perform micro deviation correction fitting of the 6-degree-of-freedom micro deviation according to the trajectory compensation action, and output a 6-degree-of-freedom residual deviation; a positioning pin extension amount calculation module, configured to extract a planar deviation from the 6-degree-of-freedom residual deviation to calculate a positioning pin extension amount; a deflected pin rotation angle calculation module, configured to extract an angular deviation from the 6-degree-of-freedom residual deviation to calculate a deflected pin rotation angle, where the positioning pin extension amount and the deflected pin rotation angle constitute the positioning pin compensation action.

[0011] In a possible implementation, the auxiliary assembly module includes: a three-force balance condition calling module for locally calling the three-force balance condition; a three-force deviation solving module for solving the three-force deviation of the fitting pressure parameter according to the three-force balance condition and outputting initial three-force control parameters, where the initial three-force control parameters include the upper pressing pressure, the lower top supporting force, and the positioning pin contact force; a PID parameter tuning module for performing PID tuning of the initial three-force control parameters according to the real-time fitting pressure and the three-force deviation of the three-force balance condition during the process of driving the linkage displacement of the upper pressing mechanism, the lower top structure, and the K electric positioning pins by using the initial three-force control parameters.

[0012] In a possible implementation, the collision-free trajectory construction module includes: an obstacle three-dimensional grid map construction module for presetting a grid resolution and constructing an obstacle three-dimensional grid map according to the 6-degree-of-freedom pose deviation with the grid resolution as a constraint; a clamping behavior simulation module for simulating the clamping behaviors of the K alternative trajectories and outputting K joint acceleration sequences and K clamping end velocity sequences after searching for the K alternative trajectories in the obstacle three-dimensional grid map with collision-free as the search condition; a clamping stability fusion evaluation module for performing a clamping stability fusion evaluation based on the K joint acceleration sequences and the K clamping end velocity sequences and screening and positioning the collision-free trajectory according to the evaluation results.

[0013] In a possible implementation, the clamping stability fusion evaluation module includes: a clamping end velocity constraint matching module for matching the clamping end velocity constraint according to the mass characteristics of the target workpiece; a joint acceleration limit extraction module for retrieving and extracting the joint acceleration limit according to the robot arm ID; an acceleration deviation rate acquisition module for traversing the first joint acceleration sequence by using the joint acceleration limit to obtain the acceleration deviation rates of Q acceleration deviation nodes; a weighted fusion module for weighted-fusing the acceleration deviation rates of the Q acceleration deviation nodes according to the adjacent time differences of the Q acceleration deviation nodes and outputting a first deviation feature; a second deviation feature output module for, by analogy, evaluating the first clamping end velocity sequence by using the clamping end velocity and outputting a second deviation feature; a first stability coefficient output module for weighted-fusing the first deviation feature and the second deviation feature by using a preset stability weight and outputting a first stability coefficient; a collision-free trajectory screening module for, by analogy, performing a clamping stability fusion evaluation of the K alternative trajectories, outputting K stability coefficients, and sorting the K alternative trajectories in ascending order according to the K stability coefficients to screen the collision-free trajectory.

[0014] The present application also provides an intelligent control method for assisting upper pressing and lower jacking positioning pins, including: after the robotic arm grasps the target workpiece in the rough positioning area, constructing a collision-free trajectory through pose deviation analysis; after driving the robotic arm to transfer the target workpiece into the vision working area by using the collision-free trajectory, triggering microscopic deviation analysis and outputting trajectory compensation actions and positioning pin compensation actions; during the process of driving the robotic arm to clamp the target workpiece to the force sensing guiding area by using the collision-free trajectory corrected by the trajectory compensation actions, synchronously using the positioning pin compensation actions to pre-extend K electric positioning pins on the fixture base; after the robotic arm clamps the target workpiece into the force sensing guiding area and pre-fits with the K electric positioning pins, activating the force sensor to collect the fitting pressure parameters; performing three-force closed-loop optimization based on the fitting pressure parameters, outputting three-force dynamic control parameters, and assisting the linkage displacement of the upper pressing mechanism, the lower jacking structure and the K electric positioning pins to perform fixture-assisted assembly of the target workpiece.

[0015] It is intended to propose an intelligent control device and method for assisting upper pressing and lower jacking positioning pins through the present application. The trajectory construction module is used to construct a collision-free trajectory through pose deviation analysis after the robotic arm grasps the target workpiece in the rough positioning area. The deviation analysis module is used to trigger microscopic deviation analysis and output trajectory compensation actions and positioning pin compensation actions after driving the robotic arm to transfer the target workpiece into the vision working area by using the collision-free trajectory. The positioning pin extension module is used to synchronously use the positioning pin compensation actions to pre-extend K electric positioning pins on the fixture base during the process of driving the robotic arm to clamp the target workpiece to the force sensing guiding area by using the collision-free trajectory corrected by the trajectory compensation actions. The pressure parameter acquisition module is used to activate the force sensor to collect the fitting pressure parameters after the robotic arm clamps the target workpiece into the force sensing guiding area and pre-fits with the K electric positioning pins. The assisted assembly module is used to perform three-force closed-loop optimization based on the fitting pressure parameters, output three-force dynamic control parameters, and assist the linkage displacement of the upper pressing mechanism, the lower jacking structure and the K electric positioning pins to perform fixture-assisted assembly of the target workpiece. The technical effect of improving the assembly accuracy is achieved. Brief Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments of the present invention will be briefly introduced below. Flowcharts are used in the present application to illustrate the operations performed by the devices according to the embodiments of the present application. It should be understood that the operations in the front or below do not necessarily need to be executed precisely in sequence. On the contrary, according to the need, they can be executed in reverse order or simultaneously. At the same time, other operations can also be added to these processes, or one or several steps of operations can be removed from these processes.

[0017] Figure 1 It is a schematic structural diagram of an intelligent control device for assisting upper pressing and lower jacking positioning pins provided by an embodiment of the present application.

[0018] Figure 2 Schematic flow diagram of the intelligent control method for the upper pressing and lower jacking positioning pin assistance provided by the embodiments of the present application.

[0019] Explanation of reference numerals: Trajectory construction module 10, deviation analysis module 20, positioning pin extension module 30, pressure parameter acquisition module 40, auxiliary assembly module 50. Detailed implementation manners

[0020] The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented according to the content of the description. And in order to make the above and other purposes, features and advantages of the present application more obvious and understandable, the following specifically gives the detailed implementation manners of the present application.

[0021] In order to make the purpose, technical solution and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings. The described embodiments should not be regarded as limitations of the present application. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present application.

[0022] In the following description, "some embodiments" are involved, which describe a subset of all possible embodiments. However, it can be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments, and can be combined with each other without conflict. The terms "first\second" involved are only used to distinguish similar objects and do not represent a specific order for the objects. The terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, device, product or server including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or modules not clearly listed or inherent to these processes, methods, products or devices. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present application belongs. The terms used herein are only for the purpose of describing the embodiments of the present application.

[0023] The embodiments of the present application provide an intelligent control upper pressing and lower jacking positioning pin assistance device, as Figure 1 shown, the device includes:

[0024] A trajectory construction module 10, configured to construct a collision-free trajectory through pose deviation analysis after the robotic arm grabs a target workpiece in the rough positioning area.

[0025] Specifically, first, the robotic arm grasps the target workpiece in the rough positioning area (where the distance between the workpiece and the fixture is greater than 50 mm but less than or equal to 100 mm). This area is to ensure that there is enough distance between the workpiece and the fixture when the robotic arm grasps the workpiece, avoiding collisions during the grasping process. After grasping the target workpiece, through pose deviation analysis, the deviation between the actual position and the preset position of the workpiece is calculated. For example, the current position and pose information of the workpiece are obtained through a line laser scanner and compared with the preset standard position and pose to calculate the deviation value.

[0026] According to the result of the pose deviation analysis, combined with the kinematic model of the robotic arm (a mathematical model that describes the relationship between the positions and poses of the joints of the robotic arm and the position and pose of the end effector, used to calculate the motion parameters of the robotic arm), a collision-free trajectory from the current position of the robotic arm to the vision working area is constructed using a path planning algorithm (such as the sampling-based PRM algorithm or the optimization-based CHOMP algorithm). This trajectory is used to enable the robotic arm to avoid all obstacles during movement, safely transfer the target workpiece to the vision working area, and prepare for micro deviation analysis.

[0027] For example, assume that the position coordinates of the target workpiece in the rough positioning area are (x1, y1, z1), and the pose is (α1, β1, γ1), and the preset standard position coordinates are (x0, y0, z0), and the pose is (α0, β0, γ0). After obtaining the coordinates of the feature points of the workpiece through the vision sensor, the pose deviation is calculated as Δx = x1 - x0, Δy = y1 - y0, Δz = z1 - z0, Δα = α1 - α0, Δβ = β1 - β0, Δγ = γ1 - γ0. Using the PRM algorithm, the configuration space of the robotic arm is divided into multiple regions, 1000 sample points are randomly sampled to generate a connectivity graph. A path from the initial configuration of the robotic arm to the target configuration is searched in the connectivity graph. This path passes through 10 key nodes, and each node corresponds to a specific position and pose of the robotic arm. The path is decomposed into 10 motion segments, and the motion parameters (such as speed, acceleration) of each motion segment are calculated by the motion controller to ensure that the robotic arm does not collide with the surrounding environment during movement.

[0028] In a possible implementation, the trajectory construction module 10 includes: a macro position point cloud data acquisition module, which is used to trigger the line laser scanner to collect macro position point cloud data according to the grasping behavior of the robotic arm in the rough positioning area, where the macro position point cloud data includes H groups of non-coplanar feature points of the workpiece and positioning pin point clouds; a rough positioning analysis module, which is used to perform rough positioning analysis according to the macro position point cloud data and output a 6-degree-of-freedom pose deviation; a collision-free trajectory construction module, which is used to construct the collision-free trajectory according to the 6-degree-of-freedom pose deviation and then start the robotic arm to clamp and displace the workpiece.

[0029] Specifically, when the robotic arm performs a grasping action in the rough positioning area (where the workpiece is more than 50 mm but less than or equal to 100 mm away from the fixture), it triggers the line laser scanner to collect macroscopic position point cloud data. The line laser scanner generates point cloud data of the workpiece surface and the positioning pins on the fixture by emitting laser beams and receiving reflected light. These point cloud data include non-coplanar feature points of H groups of workpieces and the point cloud information of the positioning pins. The non-coplanar feature points are used to determine the spatial position and orientation of the workpiece, and the point cloud of the positioning pins is used to determine the preset assembly position of the workpiece. The collected point cloud data is transmitted to the data processing unit for preliminary filtering and noise reduction to remove possible interference points and noise.

[0030] For example, assume that the point cloud data collected by the line laser scanner in the rough positioning area includes non-coplanar feature points of H = 5 groups of workpieces and the point cloud information of the positioning pins on the fixture. These feature points are distributed in different parts of the workpiece, and the point cloud of the positioning pins reflects the preset assembly position of the workpiece. After the collected point cloud data is filtered, the noise points generated due to ambient light interference or scanner self-error are removed, and the effective feature points and the point cloud of the positioning pins are retained.

[0031] Match the collected macroscopic position point cloud data (including the feature points of the workpiece and the point cloud of the positioning pins on the fixture) with the preset standard point cloud model. The standard point cloud model is pre-generated according to the design parameters of the workpiece and the positions of the positioning pins on the fixture, and contains the ideal feature points of the workpiece and the preset positions of the positioning pins. Through the point cloud matching algorithm (such as the Iterative Closest Point algorithm ICP), calculate the deviation between the actual position and orientation of the workpiece and the preset position of the positioning pins on the fixture. The output result is a 6-degree-of-freedom pose deviation, including translational deviations in three directions (Δx, Δy, Δz) and rotational deviations in three directions (Δα, Δβ, Δγ). Analyze the calculated 6-degree-of-freedom pose deviation to determine whether the deviation is within the allowable range. If the deviation is too large, it is necessary to readjust the grasping position of the robotic arm or re-collect the point cloud data.

[0032] For example, assume that the pose deviation calculated by the point cloud matching algorithm is: Δx = 10 mm, Δy = 5 mm, Δz = 8 mm, Δα = 0.5°, Δβ = 0.3°, Δγ = 0.2°. These deviation values reflect the difference between the actual position and orientation of the workpiece and the preset position of the positioning pins on the fixture. If the preset allowable deviation range is that the translational deviation does not exceed 15 mm and the rotational deviation does not exceed 1°, then the currently calculated deviation is within the allowable range, and the subsequent trajectory construction process can continue.

[0033] According to the 6-DOF pose deviation output by the rough positioning analysis module, combined with the kinematic model of the robotic arm, a collision-free trajectory from the current position of the robotic arm to the preset position of the positioning pin on the fixture is constructed using a path planning algorithm (such as the PRM or CHOMP algorithm) to safely move the workpiece to the preset position of the positioning pin on the fixture, preparing for subsequent micro deviation analysis and precise positioning. The generated trajectory is optimized to ensure that the robotic arm avoids all obstacles during movement and moves smoothly and efficiently. The optimization process includes adjusting parameters such as the smoothness, speed, and acceleration of the trajectory. After the collision-free trajectory is constructed, the robotic arm is activated to grip the workpiece and move it to the preset position of the positioning pin on the fixture according to the planned trajectory.

[0034] In a possible implementation, the rough positioning analysis module includes: a workpiece CAD model calling module for locally calling the workpiece CAD model according to the workpiece ID of the target workpiece; a 6-DOF pose deviation calculation module for registering the macro position point cloud with the workpiece CAD model through the ICP algorithm and calculating the 6-DOF pose deviation of the target workpiece relative to the fixture, where the 6-DOF pose deviation consists of a translation component and a rotation component.

[0035] Specifically, using the workpiece ID as an index, the CAD model of the corresponding workpiece is retrieved from the locally stored CAD model library. For example, if the workpiece ID is "Part_001", the system will call the CAD model file associated with this ID. The CAD model contains the ideal geometric shape and feature point information of the workpiece and is the basis for pose deviation calculation.

[0036] The collected macro position point cloud data is downsampled and filtered to reduce the computational amount and improve the registration accuracy. The processed point cloud data is registered with the CAD model. The ICP algorithm (point cloud matching algorithm) iteratively calculates the nearest point pairs between the point cloud data and the CAD model and minimizes the distance between them to obtain the best match. The final transformation matrix is obtained through the ICP algorithm, and the translation component and rotation component are extracted from the final transformation matrix as the 6-DOF pose deviation. These deviation values reflect the difference between the actual position and orientation of the workpiece and the preset position of the positioning pin on the fixture.

[0037] In a possible implementation, the collision-free trajectory construction module includes: an obstacle three-dimensional grid map construction module, configured to preset a grid resolution, and construct an obstacle three-dimensional grid map according to the 6-degree-of-freedom pose deviation with the grid resolution as a constraint; a gripping behavior simulation module, configured to simulate the gripping behaviors of the K alternative trajectories after obtaining the K alternative trajectories by searching in the obstacle three-dimensional grid map with collision-free as the search condition, and output K joint acceleration sequences and K gripping end velocity sequences; a gripping stability fusion evaluation module, configured to perform a gripping stability fusion evaluation based on the K joint acceleration sequences and the K gripping end velocity sequences, and screen and locate the collision-free trajectory according to the evaluation result.

[0038] Specifically, a predefined grid resolution is set, for example, 1 cm³, to divide the working space into small three-dimensional grid cells. According to the 6-degree-of-freedom pose deviation of the workpiece and the surrounding environment information (including other devices, tools, and possible obstacles), the positions and shapes of the obstacles in the working space are mapped into the three-dimensional grid map. Each grid cell is marked as "obstacle-free" or "obstacle", thus forming a detailed obstacle distribution map. With the grid resolution as a constraint, a balance between the accuracy of the map and the computational efficiency is ensured. A higher resolution can provide more accurate obstacle information but increases the computational amount; a lower resolution has the opposite effect.

[0039] For example, assume that the preset grid resolution is 1 cm³ and the working space is 1 m³ (100 cm × 100 cm × 100 cm), then the entire working space is divided into 1,000,000 grid cells. According to the 6-degree-of-freedom pose deviation of the workpiece (Δx = 10 mm, Δy = 5 mm, Δz = 8 mm, Δα = 0.5°, Δβ = 0.3°, Δγ = 0.2°) and the surrounding environment information, the positions and shapes of the obstacles are mapped into the grid map. For example, the devices and tools around the robotic arm are marked as "obstacle" grid cells.

[0040] With collision-free as the search condition, search for possible collision-free trajectories in the obstacle three-dimensional grid map. Use path planning algorithms (such as the A* algorithm, RRT algorithm, etc.) to search for multiple alternative trajectories from the current position of the robotic arm to the target position (the positioning pin on the fixture). Assume that K alternative trajectories are searched. Simulate the gripping behaviors of each alternative trajectory, and calculate the joint acceleration sequence and the gripping end velocity sequence of the robotic arm on each trajectory. These sequences reflect the dynamic characteristics of the robotic arm when performing the gripping task. Output K joint acceleration sequences and K gripping end velocity sequences to provide data support for the gripping stability evaluation.

[0041] For example, assume that K = 5 alternative trajectories are searched. The clamping behavior is simulated for each trajectory, and the following results are obtained: Trajectory 1: joint acceleration sequence [a1, a2, ..., a N , clamping end velocity sequence [v1, v2, ..., v N ; Trajectory 2: joint acceleration sequence [a1', a2', ..., a N '], clamping end velocity sequence [v1', v2', ..., v N '];... Trajectory 5: joint acceleration sequence [a1'''', a2'''', ..., a N '''], clamping end velocity sequence [v1'''', v2'''', ..., v N '''].

[0042] Define the evaluation criteria for clamping stability, such as the smoothness of joint acceleration, the uniformity of clamping end velocity, the smoothness of the trajectory, etc. These criteria can be adjusted and optimized according to the actual application scenario. Conduct a comprehensive evaluation of the joint acceleration sequences and clamping end velocity sequences of the K alternative trajectories. By methods such as weighted average and fuzzy logic, multiple evaluation indicators are fused into a comprehensive score. According to the comprehensive score, select the trajectory with the highest score as the final collision-free trajectory for the motion control of the robotic arm.

[0043] For example, assume that the following evaluation criteria are defined: smoothness of joint acceleration (weight 0.4), uniformity of clamping end velocity (weight 0.3), smoothness of the trajectory (weight 0.3). Conduct a comprehensive evaluation of the 5 alternative trajectories, and the following comprehensive scores are obtained: Trajectory 1: comprehensive score 0.75; Trajectory 2: comprehensive score 0.80; Trajectory 3: comprehensive score 0.65; Trajectory 4: comprehensive score 0.70; Trajectory 5: comprehensive score 0.85; According to the comprehensive score, select Trajectory 5 with the highest score as the final collision-free trajectory.

[0044] In a possible implementation manner, the clamping stability fusion evaluation module includes: a clamping end velocity constraint matching module, configured to match the clamping end velocity constraint according to the mass characteristics of the target workpiece; a joint acceleration limit extraction module, configured to retrieve and extract the joint acceleration limit according to the robot arm ID; an acceleration deviation rate acquisition module, configured to traverse the first joint acceleration sequence by using the joint acceleration limit to obtain Q acceleration deviation rates of Q acceleration deviation nodes; a weighted fusion module, configured to perform weighted fusion on the Q acceleration deviation rates according to the adjacent time differences of the Q acceleration deviation nodes and output a first deviation feature; a second deviation feature output module, configured to take the clamping end velocity to evaluate the first clamping end velocity sequence by analogy and output a second deviation feature; a first stability coefficient output module, configured to perform weighted fusion on the first deviation feature and the second deviation feature by using a preset stability weight and output a first stability coefficient; a collision-free trajectory screening module, configured to perform the clamping stability fusion evaluation on the K alternative trajectories by analogy, and after outputting K stability coefficients, arrange the K alternative trajectories in ascending order according to the K stability coefficients to screen the collision-free trajectories.

[0045] Specifically, according to the mass characteristics of the target workpiece (such as weight, size, etc.), a suitable clamping end velocity constraint is matched. Different workpiece mass characteristics require different clamping velocities to ensure the stability and safety of the clamping process. By using the mass characteristic parameters of the workpiece (such as weight, size, etc.) as input, the corresponding clamping end velocity constraint is retrieved from a preset database. For example, for a heavier workpiece, a lower clamping velocity is required to ensure stability.

[0046] For example, assume that the mass characteristics of the target workpiece are: weight 10 kg, size 500 mm × 300 mm × 200 mm. The system retrieves the matching clamping end velocity constraint from the database according to these parameters: the maximum velocity does not exceed 100 mm / s.

[0047] According to the robot arm ID, the joint acceleration limit of the robot arm is retrieved and extracted. Different robot arm models have different joint acceleration limits to ensure the motion safety and stability of the robot arm. By using the robot arm ID as an index, the joint acceleration limit of the corresponding robot arm is retrieved from the robot arm parameter database stored locally.

[0048] For example, assume that the robot arm ID is "Robot_001", and the system retrieves the joint acceleration limit of this robot arm from the database: the maximum accelerations of joints 1 to 6 are 50 rad / s², 40 rad / s², 30 rad / s², 20 rad / s², 15 rad / s², and 10 rad / s² respectively.

[0049] Using the retrieved joint acceleration limit, traverse the first joint acceleration sequence (corresponding to the first alternative trajectory) to calculate the Q acceleration deviation rates of Q acceleration deviation nodes. The acceleration deviation rate reflects the deviation degree between the actual acceleration and the limit acceleration. Specifically, traverse the first joint acceleration sequence, and for each time point, calculate the difference between the actual acceleration and the joint acceleration limit, that is, the acceleration deviation rate. The formula is: acceleration deviation rate = (actual acceleration - limit acceleration) / limit acceleration. Record the nodes with acceleration deviation rates greater than or equal to the preset threshold as acceleration deviation nodes.

[0050] For example, assume that the first joint acceleration sequence is: [30rad / s², 45rad / s², 55rad / s², 60rad / s², 40rad / s²], and the joint acceleration limit is 50rad / s². Traverse this sequence to calculate the acceleration deviation rate: At the 1st time point: (30 - 50) / 50 = -0.4; At the 2nd time point: (45 - 50) / 50 = -0.1; At the 3rd time point: (55 - 50) / 50 = 0.1; At the 4th time point: (60 - 50) / 50 = 0.2; At the 5th time point: (40 - 50) / 50 = -0.2. Assume that the preset acceleration deviation rate threshold is 0.1, then the 3rd and 4th time points are acceleration deviation nodes, and the corresponding acceleration deviation rates are 0.1 and 0.2 respectively.

[0051] According to the adjacent time differences of the Q acceleration deviation nodes, weighted fusion of the Q acceleration deviation rates is performed to output the first deviation feature. Weighted fusion takes into account the time factor to more accurately reflect the impact of acceleration deviation. Specifically, calculate the adjacent time differences of each acceleration deviation node (i.e., the time interval between adjacent deviation nodes). Weight the acceleration deviation rate according to the adjacent time difference. The formula is: weighted deviation rate = acceleration deviation rate × (1 / adjacent time difference). Add up all the weighted deviation rates to obtain the first deviation feature.

[0052] For example, assume Q = 2 acceleration deviation nodes, the acceleration deviation rates are 0.1 and 0.2 respectively, and the adjacent time differences are 0.5s and 1.0s respectively. Calculate the weighted deviation rate: For the 1st deviation node: 0.1 × (1 / 0.5) = 0.2; For the 2nd deviation node: 0.2 × (1 / 1.0) = 0.2; The first deviation feature = 0.2 + 0.2 = 0.4.

[0053] Using the clamping end velocity constraint, evaluate the first clamping end velocity sequence (corresponding to the first alternative trajectory) and output the second deviation feature. The second deviation feature reflects the deviation degree between the actual value and the constraint value of the clamping end velocity. Specifically, traverse the first clamping end velocity sequence, and for each time point, calculate the difference between the actual velocity and the clamping end velocity constraint, that is, the velocity deviation rate. The formula is: velocity deviation rate = (actual velocity - velocity constraint) / velocity constraint. Weight and fuse all the velocity deviation rates to obtain the second deviation feature.

[0054] Using the preset stability weight, weight and fuse the first deviation feature and the second deviation feature, and output the first stability coefficient. The stability coefficient reflects the clamping stability of the trajectory. For example, the weight of the acceleration deviation feature is 0.6, and the weight of the velocity deviation feature is 0.4. Calculate the stability coefficient. The formula is: stability coefficient = first deviation feature × weight 1 + second deviation feature × weight 2.

[0055] Repeat the above evaluation process for each alternative trajectory to obtain K stability coefficients. Arrange the K stability coefficients in ascending order, and select the trajectory with the smallest stability coefficient as the final collision-free trajectory.

[0056] The deviation analysis module 20 is used to trigger the microscopic deviation analysis after using the collision-free trajectory to drive the robotic arm to transfer the target workpiece into the vision working area, and output the trajectory compensation action and the positioning pin compensation action.

[0057] Specifically, the vision working area refers to the area for high-precision vision detection, which is equipped with a high-precision vision system, such as a binocular stereo vision camera or a 3D laser scanner. When the robotic arm transfers the target workpiece to the vision working area, use the high-precision vision system (such as a binocular stereo vision camera or a 3D laser scanner) to perform microscopic deviation detection on the workpiece. For example, the binocular stereo vision camera takes images of the workpiece from different angles through two cameras, and uses the parallax principle to calculate the three-dimensional point cloud data on the surface of the workpiece.

[0058] Compare the detected actual position and posture of the workpiece with the preset standard position and posture, and calculate the microscopic deviation. For example, through the point cloud matching algorithm, align the actual point cloud with the standard point cloud, calculate the deviation value of each point, and thus obtain the overall deviation of the workpiece.

[0059] According to the microscopic deviation, use the inverse kinematics algorithm to calculate the trajectory compensation action of the robotic arm and the compensation action of the positioning pin. For example, if the workpiece is offset by Δx in the x direction, the end of the robotic arm needs to move -Δx in the x direction for compensation; at the same time, according to the offset amount of the workpiece, calculate the length compensation value that the positioning pin needs to extend.

[0060] For example, assume that the vision system in the vision workspace detects that the target workpiece is offset by 2 mm in the x direction, 1 mm in the y direction, 0.5 mm in the z direction, and rotated by 0.1 degrees about the x axis, 0.2 degrees about the y axis, and 0.3 degrees about the z axis in terms of attitude. The deviation analysis module 20 calculates through the inverse kinematics algorithm that the end of the robotic arm needs to move -2 mm in the x direction, -1 mm in the y direction, -0.5 mm in the z direction, and simultaneously rotate -0.1 degrees about the x axis, -0.2 degrees about the y axis, and -0.3 degrees about the z axis as the trajectory compensation action. For the positioning pin compensation action, assume that the initial extended length of the positioning pin is L0, and the additional extended length ΔL of the positioning pin is calculated according to the offset of the workpiece. For example, if the workpiece is offset by 0.5 mm in the z direction, the positioning pin needs to be additionally extended by 0.5 mm, that is, ΔL = 0.5 mm.

[0061] In a possible implementation manner, the deviation analysis module 20 includes: an image acquisition module, configured to synchronously activate the main perspective camera and the auxiliary perspective camera after the target workpiece enters the vision workspace, and acquire the workpiece image and the positioning pin image; a feature matching module, configured to perform edge detection and feature matching on the workpiece image and the positioning pin image respectively, and identify the K spatial positions of the K target positioning holes on the target workpiece and the W spatial positions of the W electric positioning pins on the fixture, where W is a positive integer greater than K; a neighboring positioning pin matching module, configured to perform neighboring positioning pin matching of the K target positioning holes according to the K spatial positions of the positioning holes and the W spatial positions of the W positioning pins, and obtain K hole-pin matching groups; a 6-degree-of-freedom micro deviation calculation module, configured to extract the K electric positioning pins from the K hole-pin matching groups, and calculate and output a 6-degree-of-freedom micro deviation according to the K spatial positions of the positioning holes and the K spatial positions of the K electric positioning pins; and an associated compensation correction module, configured to perform associated compensation correction according to the 6-degree-of-freedom micro deviation, and output the trajectory compensation action and the positioning pin compensation action.

[0062] Specifically, after the target workpiece enters the vision workspace, the main perspective camera and the auxiliary perspective camera are synchronously activated to acquire the workpiece image and the positioning pin image. The main perspective camera and the auxiliary perspective camera are respectively installed at different positions in the vision workspace to obtain multi-perspective images of the workpiece and the positioning pin. When the robotic arm moves the target workpiece to the vision workspace, the two cameras are triggered to synchronously acquire images. The main perspective camera is mainly responsible for acquiring the image of the workpiece, and the auxiliary perspective camera is mainly responsible for acquiring the image of the positioning pin on the fixture. For example, acquire the main perspective image facing the positioning hole of the workpiece and the auxiliary perspective image of the fixture positioning pin at a 45-degree skew.

[0063] Edge detection and feature matching are respectively performed on the workpiece image and the positioning pin image to identify the spatial positions of the K target positioning holes on the target workpiece and the spatial positions of the W electric positioning pins on the jig. Among them, an edge detection algorithm, such as Canny edge detection, is used to extract the edge information in the image. A feature matching algorithm, such as SIFT, SURF or ORB, is used to identify and match the positioning holes on the workpiece and the positioning pins on the jig. Based on the matching results, the spatial positions of each positioning hole and positioning pin are determined.

[0064] According to the spatial positions of the K target positioning holes and the spatial positions of the W electric positioning pins, adjacent positioning pin matching for the K target positioning holes is performed to obtain K hole-pin matching groups. Specifically, the distance between each positioning hole and all positioning pins is calculated. The nearest positioning pin is selected for each positioning hole to form a hole-pin matching group. If there are multiple positioning pins with similar distances to a certain positioning hole, the nearest positioning pin can be selected, or the selection can be made according to other rules (such as preferentially selecting the positioning pins that have been pre-extended).

[0065] For example, assume that the distance between the first positioning hole and the first positioning pin is the closest, the distance between the second positioning hole and the second positioning pin is the closest, and the distance between the third positioning hole and the third positioning pin is the closest. The matching results are: hole-pin matching group 1: the first positioning hole and the first positioning pin; hole-pin matching group 2: the second positioning hole and the second positioning pin; hole-pin matching group 3: the third positioning hole and the third positioning pin.

[0066] After extracting the K electric positioning pins from the K hole-pin matching groups, based on the spatial positions of the K target positioning holes and the spatial positions of the K electric positioning pins, the 6-degree-of-freedom micro deviation is solved and output. Specifically, for each hole-pin matching group, the spatial position deviation between the positioning hole and the corresponding positioning pin is calculated. Using the least squares method or other optimization algorithms, the deviations of multiple hole-pin matching groups are combined to solve the 6-degree-of-freedom micro deviation of the target workpiece relative to the jig (including translational deviations in three directions and rotational deviations in three directions).

[0067] In addition, the SVD decomposition can be used to calculate the 6-DOF microscopic deviation. Specifically, taking the first set of hole-pin matching groups (for example, the first positioning hole and the first positioning pin) as the reference, a local coordinate system is established. Assuming that the spatial position of the first positioning hole is P1 and the spatial position of the first positioning pin is Q1, the origin of the local coordinate system can be set at P1, and the direction vector can be determined by Q1−P1. For each set of hole-pin matching groups, the relative pose transformation matrix between the positioning hole and the positioning pin is calculated. All relative pose transformation matrices are converted into homogeneous coordinate forms, and an overall transformation matrix is constructed. The SVD decomposition is performed on the overall transformation matrix, and based on the results of the SVD decomposition, the optimal pose transformation matrix is calculated. If the importance of different matching groups is considered, different weights can be assigned to each relative pose transformation matrix, and then the weighted average transformation matrix is calculated. The final 6-DOF microscopic deviation can be solved through the weighted average transformation matrix.

[0068] Based on the 6-DOF microscopic deviation, correlation compensation and correction are performed, and the trajectory compensation action and the positioning pin compensation action are output. Specifically, according to the calculated 6-DOF microscopic deviation, the trajectory compensation action of the robotic arm is calculated to adjust the motion trajectory of the robotic arm so that the target workpiece can be more accurately aligned with the positioning pin. At the same time, the compensation action of the positioning pin is calculated to adjust the position and pose of the positioning pin to better match the positioning hole of the target workpiece. The compensated trajectory and the positioning pin action instructions are output for use by subsequent modules.

[0069] For example, assume that the compensation actions calculated according to the microscopic deviation are as follows: Trajectory compensation action: The robotic arm moves 0.5 mm in the x direction, 0.3 mm in the y direction, and 0.2 mm in the z direction; rotates 0.1° around the x axis, 0.05° around the y axis, and 0.08° around the z axis. Positioning pin compensation action: The first positioning pin extends 0.2 mm in the z direction; the second positioning pin extends 0.1 mm in the y direction; the third positioning pin extends 0.15 mm in the x direction.

[0070] In a possible implementation manner, the correlation compensation and correction module includes: a 6-DOF microscopic deviation decomposition module for decomposing the 6-DOF microscopic deviation to obtain a translational deviation and a rotational deviation; a fitting end correction amount calculation module for calculating the fitting end correction amount of the robotic arm according to the translational deviation; a gripping pose correction amount calculation module for calculating the gripping pose correction amount of the robotic arm according to the rotational deviation, where the fitting end correction amount and the gripping pose correction amount constitute the trajectory compensation action; and a positioning pin compensation calculation module for performing positioning pin compensation calculation after correcting the 6-DOF microscopic deviation according to the trajectory compensation action to obtain the positioning pin compensation action.

[0071] Specifically, the translational components (Δx, Δy, Δz) and rotational components (Δα, Δβ, Δγ) are extracted from the 6-degree-of-freedom microscopic deviation. The translational components represent the translational deviation of the target workpiece in space, and the rotational components represent the rotational deviation of the target workpiece in space.

[0072] The translational deviation is converted into the correction amount of the end effector of the robotic arm. The correction amount represents the distance that the end of the robotic arm needs to move in space to compensate for the translational deviation. The calculation formula for the correction amount is: fitting end correction amount = (Δx × safety factor, Δy × safety factor, Δz + anti-collision margin). Among them, a safety factor (less than 1) is introduced to reduce the correction amount and avoid the robotic arm from moving too fast or too violently; an anti-collision margin (a positive value) is added to ensure that the robotic arm has enough space in the Z direction to avoid collisions. The rotational deviation is converted into the clamping pose correction amount of the end effector of the robotic arm. The correction amount represents the angle that the end of the robotic arm needs to rotate in space to compensate for the rotational deviation. The calculation formula for the correction amount is: clamping pose correction amount = (Δα × rotational attenuation coefficient, Δβ × rotational attenuation coefficient, Δγ × rotational attenuation coefficient). Among them, a rotational attenuation coefficient (less than 1) is introduced to reduce the rotational correction amount and avoid the robotic arm from rotating excessively, thereby improving the stability and reliability of the correction.

[0073] According to the fitting end correction amount and the clamping pose correction amount, the position and pose of the target workpiece are corrected. The deviation between the corrected target workpiece and the positioning pin is recalculated. According to the corrected deviation, the compensation action of the positioning pin is calculated, including the extension length and direction adjustment of the positioning pin.

[0074] In a possible implementation manner, the positioning pin compensation calculation module includes: a 6-degree-of-freedom residual deviation output module, which is used to perform microscopic deviation correction fitting of the 6-degree-of-freedom microscopic deviation according to the trajectory compensation action and output the 6-degree-of-freedom residual deviation; a positioning pin extension amount calculation module, which is used to extract the planar deviation from the 6-degree-of-freedom residual deviation to calculate the positioning pin extension amount; a deviation pin rotation angle calculation module, which is used to extract the angular deviation from the 6-degree-of-freedom residual deviation to calculate the deviation pin rotation angle, where the positioning pin extension amount and the deviation pin rotation angle constitute the positioning pin compensation action.

[0075] Specifically, after the robotic arm performs the trajectory compensation action, the deviation between the target workpiece and the positioning pin is recalculated. The least squares method, SVD decomposition or other optimization algorithms are used to fit the corrected deviation to obtain the 6-degree-of-freedom residual deviation (including the translational residual deviation in three directions and the rotational residual deviation in three directions).

[0076] Extract the translational residual deviation in the six-degree-of-freedom residual deviation. Calculate the extension amount of each positioning pin according to the translational residual deviation. The extension amount represents the distance that the positioning pin needs to extend to compensate for the translational residual deviation. Extract the rotational residual deviation in the six-degree-of-freedom residual deviation. Calculate the rotation angle of the biasing pin according to the rotational residual deviation. The rotation angle represents the angle that the positioning pin needs to rotate to compensate for the rotational residual deviation.

[0077] The positioning pin extension module 30 is used to pre-extension the K electric positioning pins on the fixture base synchronously by using the positioning pin compensation action during the process of the robotic arm gripping the target workpiece and moving it to the force sense guiding area along the collision-free trajectory corrected by the trajectory compensation action.

[0078] Specifically, according to the positioning pin compensation action generated by the deviation analysis module 20, the K electric positioning pins on the fixture base are controlled to pre-extension by the positioning pin drive controller (such as a servo motor controller). For example, the extension length of each positioning pin is determined by the rotation angle of the servo motor, and the rotation of the servo motor is precisely controlled by the pulse control signal, so as to realize the extension action of the positioning pin.

[0079] While the robotic arm grips the target workpiece and moves along the corrected collision-free trajectory, the positioning pin extension module 30 is synchronously controlled with the movement of the robotic arm. For example, through the PLC (Programmable Logic Controller) or industrial bus communication technology, the movement state of the robotic arm is synchronized with the extension state of the positioning pin in real time to ensure that the two actions are coordinated.

[0080] For example, assume that there are 4 electric positioning pins (K = 4) on the fixture base. After the positioning pin extension module 30 receives the compensation action instruction from the deviation analysis module 20, it controls the 4 positioning pins to extend respectively through the servo motor controller. If the initial extension length of the positioning pin is 10mm, according to the compensation action instruction, the first positioning pin needs to extend an additional 0.5mm, the second positioning pin needs to extend an additional 0.3mm, the third positioning pin needs to extend an additional 0.4mm, and the fourth positioning pin needs to extend an additional 0.2mm. The servo motor controller calculates the rotation angle that each servo motor needs to rotate according to these compensation values, and drives the servo motor through the pulse signal to make the positioning pin reach the pre-extension state. When the robotic arm grips the target workpiece and moves along the corrected collision-free trajectory, the positioning pin extension module 30 communicates with the movement controller of the robotic arm through the PLC. For example, when the robotic arm moves a preset distance (such as 10mm), the positioning pin extension module 30 adjusts the extension speed and length of the positioning pin according to the current position and speed of the robotic arm to ensure that the positioning pin has completed the pre-extension action when the robotic arm reaches the force sense guiding area.

[0081] The pressure parameter acquisition module 40 is used to activate the force sensor to acquire the fitting pressure parameters after the robotic arm grips the target workpiece and enters the force sensing guidance area and pre-fits with K electric positioning pins.

[0082] Specifically, the force sensing guidance area refers to the area where the robotic arm moves the target workpiece to make initial contact and fit with the positioning pins. In this area, the force sensor starts to work and acquires the pressure parameters during the fitting process in real time. A high-precision force sensor (such as a six-axis force sensor) is installed at the end of the robotic arm or on the positioning pins to acquire the pressure parameters during the fitting process in real time. The six-axis force sensor can simultaneously measure three components of force (F x , F y , F z ) and three components of torque (M x , M y , M z ). This kind of sensor can provide comprehensive force and torque information for precise control of the assembly process.

[0083] When the robotic arm grips the target workpiece and enters the force sensing guidance area and pre-fits with K electric positioning pins, the force sensor starts to acquire the fitting pressure parameters. At this time, the movement speed of the robotic arm will decrease to ensure the accuracy and safety of the fitting process. The force sensor converts the acquired pressure parameters (F x , F y , F z , M x , M y , M z ) into electrical signals and transmits them to the control computer through a data acquisition card (DAQ). The data acquisition card is used to convert the analog signals output by the sensor into digital signals for processing and analysis.

[0084] The acquired signals contain noise and need to be filtered. For example, a low-pass filter can be used to remove high-frequency noise and retain the low-frequency effective signals. In addition, the signals can also be amplified or normalized for better analysis and use of these data.

[0085] The acquired pressure parameters are fed back to the control module in real time for the three-force closed-loop optimization process. These parameters can reflect the contact force and torque between the workpiece and the positioning pins and provide a basis for adjusting the actions of the robotic arm and the positioning pins.

[0086] For example, assume that a six-axis force sensor is installed at the end of the robotic arm to measure the force and torque when the workpiece contacts the positioning pins. At the same time, a small force sensor is also installed on each positioning pin to measure the reaction force when the positioning pin contacts the workpiece. When the robotic arm grips the target workpiece and enters the force sensing guidance area and pre-fits with the positioning pins, the pressure parameters acquired by the force sensor are as follows: F x= 10 N (force in the x - direction), F y = 5 N (force in the y - direction), F z = 20 N (force in the z - direction), M x = 0.5 Nm (torque about the x - axis), M y = 0.3 Nm (torque about the y - axis), M z = 0.2 Nm (torque about the z - axis). The acquired signals are filtered through a low - pass filter (cut - off frequency is 10 Hz) to remove high - frequency noise. Then, the signals are amplified by 10 times for clearer observation of small changes. The acquired pressure parameters are transmitted to the control computer in real - time for three - force closed - loop optimization. For example, if the pressure in the F z direction exceeds a preset threshold (such as 25 N), the system will automatically adjust the downward pressure of the robotic arm to avoid over - squeezing the workpiece.

[0087] The auxiliary assembly module 50 is used to perform three - force closed - loop optimization based on the fitting pressure parameters, output three - force dynamic control parameters, and assist the linkage displacement of the upper pressing mechanism, the lower jacking structure, and K electric positioning pins for jig - assisted assembly of the target workpiece.

[0088] Specifically, the three - force closed - loop optimization means dynamically adjusting the actions of the upper pressing mechanism, the lower jacking structure, and the electric positioning pins according to the pressure parameters collected in real - time through a closed - loop control algorithm to ensure that the force and torque are within the preset range. Receive the real - time pressure parameters from the pressure parameter acquisition module 40, which reflect the contact force and torque between the workpiece and the positioning pins. Use a closed - loop control algorithm (such as the PID control algorithm) to optimize the actions of the upper pressing mechanism, the lower jacking structure, and the electric positioning pins in real - time. The closed - loop control algorithm dynamically adjusts the actions of each actuator according to the pressure parameters collected in real - time to ensure that the force and torque are within the preset range. According to the results of the optimization algorithm, generate dynamic control parameters, including the downward pressure of the upper pressing mechanism, the thrust of the lower jacking structure, the telescopic length of the positioning pins, etc. These parameters are updated in real - time to adapt to the dynamic changes during the assembly process. Convert the dynamic control parameters into specific control signals and send them to the drive controllers of the upper pressing mechanism, the lower jacking structure, and the electric positioning pins. For example, generate a pulse signal to control the rotation angle of the servo motor, thereby adjusting the telescopic length of the positioning pins. For example, if it is detected that the pressure in the F z direction is too large, the system will automatically reduce the downward pressure of the upper pressing mechanism; if the F x or F yIf there is a pressure imbalance in a certain direction, the system will adjust the thrust direction and magnitude of the lower jacking structure. The linkage control of the upper pressing mechanism, the lower jacking structure, and the electric positioning pins is achieved through a controller (such as a PLC or a motion controller). Ensure that the actions of these actuators are coordinated to complete the precise assembly of the target workpiece. The real-time data transmission and synchronous control between the actuators are realized by using industrial bus communication technologies (such as EtherCAT or Profibus). Ensure that during the assembly process, the actions of each mechanism can be precisely coordinated.

[0089] In an embodiment of the present application, after the robotic arm grabs the target workpiece in the rough positioning area, a collision-free trajectory is constructed through pose deviation analysis, and it is transferred to the vision working area to trigger micro deviation analysis, output the trajectory and the positioning pin compensation action. When driving the robotic arm to the force sensing guidance area according to the corrected trajectory, the electric positioning pins are pre-extended synchronously with the positioning pin compensation action. After the robotic arm is pre-embedded with the positioning pins, the fitting pressure parameters are collected, and based on these parameters, a three-force closed-loop optimization is performed to output dynamic control parameters to assist the linkage displacement of the upper pressing mechanism, the lower jacking structure, and the electric positioning pins, and complete fixture-assisted assembly and other technical means, achieving the technical effect of improving the assembly accuracy.

[0090] In a possible implementation manner, the auxiliary assembly module 50 includes: a three-force balance condition calling module for locally calling the three-force balance condition; a three-force deviation solving module for solving the three-force deviation of the fitting pressure parameters according to the three-force balance condition and outputting initial three-force control parameters, where the initial three-force control parameters include the upper pressing pressure, the lower jacking support force, and the positioning pin contact force; a PID parameter tuning module for performing PID parameter tuning on the initial three-force control parameters according to the real-time fitting pressure and the three-force deviation of the three-force balance condition during the process of driving the linkage displacement of the upper pressing mechanism, the lower jacking structure, and the K electric positioning pins.

[0091] Specifically, the preset three-force balance conditions are called from the local database. These conditions include the balance relationship between the upper pressing pressure, the lower jacking support force, and the positioning pin contact force, ensuring that during the assembly process, the forces on the target workpiece in all directions reach a balanced state. The three-force balance condition can be represented as a mathematical model, for example: F 上压 +F 下顶 + =0, where F 上压 is the pressure applied by the upper pressing mechanism, F 下顶 is the support force applied by the lower jacking structure, is the contact force of the i-th positioning pin.

[0092] Using the real-time pressure data collected by the chimeric pressure sensor and combining with the three-force balance condition, calculate the current three-force deviation. Solve the initial three-force control parameters, including the upper pressing force, the lower top supporting force, and the positioning pin contact force, through an optimization algorithm (such as the least squares method). During the process of driving the linkage displacement of the upper pressing mechanism, the lower top structure, and K electric positioning pins by using the initial three-force control parameters, use a PID controller to dynamically adjust the initial three-force control parameters. The PID controller adjusts the upper pressing force, the lower top supporting force, and the positioning pin contact force according to the deviation between the real-time chimeric pressure and the three-force balance condition.

[0093] In the above text, reference is made to Figure 1 The intelligent control upper pressing and lower top positioning pin auxiliary device according to the embodiments of the present invention is described in detail. Next, reference will be made to Figure 2 Describe the intelligent control upper pressing and lower top positioning pin auxiliary method according to the embodiments of the present invention.

[0094] The intelligent control upper pressing and lower top positioning pin auxiliary method according to the embodiments of the present invention is used to solve the technical problem of low assembly accuracy existing in the existing workpiece fixture auxiliary assembly, and achieve the technical effect of improving the assembly accuracy.

[0095] The intelligent control upper pressing and lower top positioning pin auxiliary method includes: after the robotic arm grabs the target workpiece in the rough positioning area, construct a collision-free trajectory through pose deviation analysis; after using the collision-free trajectory to drive the robotic arm to transfer the target workpiece into the vision working area, trigger micro deviation analysis and output trajectory compensation actions and positioning pin compensation actions; during the process of using the collision-free trajectory corrected by the trajectory compensation actions to drive the robotic arm to grip the target workpiece and move to the force sense guidance area, synchronously use the positioning pin compensation actions to pre-extend K electric positioning pins on the fixture base; after the robotic arm grips the target workpiece and enters the force sense guidance area and pre-chimerizes with the K electric positioning pins, activate the force sensor to collect chimeric pressure parameters; perform three-force closed-loop optimization based on the chimeric pressure parameters, output three-force dynamic control parameters, assist the linkage displacement of the upper pressing mechanism, the lower top structure, and the K electric positioning pins, and perform fixture-assisted assembly of the target workpiece.

[0096] Among them, after the robotic arm grabs the target workpiece in the rough positioning area and constructs a collision-free trajectory through pose deviation analysis, it can further include: according to the grasping behavior of the robotic arm in the rough positioning area, trigger a line laser scanner to collect macroscopic position point cloud data, where the macroscopic position point cloud data includes H groups of non-coplanar feature points of the workpiece and positioning pin point cloud; perform rough positioning analysis based on the macroscopic position point cloud data and output a 6-degree-of-freedom pose deviation; after constructing the collision-free trajectory according to the 6-degree-of-freedom pose deviation, start the robotic arm to grip the workpiece and move.

[0097] Among them, for rough positioning analysis based on the macro position point cloud data and outputting the 6-degree-of-freedom pose deviation, it may further include: locally calling the workpiece CAD model according to the workpiece ID of the target workpiece; registering the macro position point cloud and the workpiece CAD model through the ICP algorithm, and calculating the 6-degree-of-freedom pose deviation of the target workpiece relative to the fixture, where the 6-degree-of-freedom pose deviation is composed of a translation component and a rotation component.

[0098] Among them, after using the collision-free trajectory to drive the robotic arm to transfer the target workpiece into the vision working area, triggering micro deviation analysis and outputting the trajectory compensation action and the positioning pin compensation action, it may further include: after the target workpiece enters the vision working area, synchronously activating the main-view camera and the auxiliary-view camera to collect the workpiece image and the positioning pin image; respectively performing edge detection and feature matching on the workpiece image and the positioning pin image to identify the spatial positions of K target positioning holes on the target workpiece and the spatial positions of W electric positioning pins on the fixture, where W is a positive integer greater than K; according to the spatial positions of the K target positioning holes and the spatial positions of the W electric positioning pins, performing adjacent positioning pin matching for the K target positioning holes to obtain K hole-pin matching groups; after extracting the K electric positioning pins from the K hole-pin matching groups, according to the spatial positions of the K target positioning holes and the spatial positions of the K electric positioning pins of the K electric positioning pins, calculating and outputting the 6-degree-of-freedom micro deviation; performing associated compensation correction based on the 6-degree-of-freedom micro deviation and outputting the trajectory compensation action and the positioning pin compensation action.

[0099] Among them, for performing associated compensation correction based on the 6-degree-of-freedom micro deviation and outputting the trajectory compensation action and the positioning pin compensation action, it may further include: decomposing the 6-degree-of-freedom micro deviation to obtain a translation deviation and a rotation deviation; calculating the fitting end correction amount of the robotic arm according to the translation deviation; calculating the clamping pose correction amount of the robotic arm according to the rotation deviation, where the fitting end correction amount and the clamping pose correction amount constitute the trajectory compensation action; after correcting the 6-degree-of-freedom micro deviation according to the trajectory compensation action, performing positioning pin compensation calculation to obtain the positioning pin compensation action.

[0100] Among them, after correcting the 6-degree-of-freedom micro deviation according to the trajectory compensation action and performing positioning pin compensation calculation to obtain the positioning pin compensation action, it may further include: performing micro deviation correction fitting of the 6-degree-of-freedom micro deviation according to the trajectory compensation action and outputting the 6-degree-of-freedom residual deviation; extracting the plane deviation from the 6-degree-of-freedom residual deviation to calculate the positioning pin extension amount; extracting the angular deviation from the 6-degree-of-freedom residual deviation to calculate the deflection pin rotation angle, where the positioning pin extension amount and the deflection pin rotation angle constitute the positioning pin compensation action.

[0101] Among them, based on the fitting pressure parameter, a three-force closed-loop optimization is performed to output three-force dynamic control parameters, which assist the linkage displacement of the upper pressing mechanism, the lower jacking structure, and the K electric positioning pins to perform the jig-assisted assembly of the target workpiece. It may further include: locally invoking the three-force balance condition; solving the three-force deviation of the fitting pressure parameter according to the three-force balance condition to output initial three-force control parameters, where the initial three-force control parameters include the upper pressing force, the lower jacking support force, and the positioning pin contact force; during the process of driving the linkage displacement of the upper pressing mechanism, the lower jacking structure, and the K electric positioning pins by using the initial three-force control parameters, perform PID tuning of the initial three-force control parameters according to the real-time fitting pressure and the three-force deviation of the three-force balance condition.

[0102] Among them, after constructing the collision-free trajectory according to the 6-degree-of-freedom pose deviation, starting the displacement of the robot arm clamping the workpiece may further include: presetting a grid resolution, and constructing a three-dimensional grid map of obstacles according to the 6-degree-of-freedom pose deviation with the grid resolution as a constraint; taking collision-free as the search condition, searching for K alternative trajectories in the three-dimensional grid map of obstacles, simulating the clamping behaviors of the K alternative trajectories, and outputting K joint acceleration sequences and K clamping end velocity sequences; performing a clamping stability fusion evaluation based on the K joint acceleration sequences and K clamping end velocity sequences, and screening and positioning the collision-free trajectory according to the evaluation results.

[0103] Among them, performing a clamping stability fusion evaluation based on the K joint acceleration sequences and K clamping end velocity sequences, and screening and positioning the collision-free trajectory according to the evaluation results may further include: matching the clamping end velocity constraint according to the mass characteristics of the target workpiece; retrieving and extracting the joint acceleration limit according to the robot arm ID; traversing the first joint acceleration sequence by using the joint acceleration limit to obtain Q acceleration deviation rates of Q acceleration deviation nodes; weighted-fusing the Q acceleration deviation rates according to the adjacent time differences of the Q acceleration deviation nodes to output a first deviation feature; and so on, evaluating the first clamping end velocity sequence by using the clamping end velocity to output a second deviation feature; weighted-fusing the first deviation feature and the second deviation feature by using a preset stability weight to output a first stability coefficient; and so on, performing a clamping stability fusion evaluation of the K alternative trajectories, outputting K stability coefficients, and then arranging the K alternative trajectories in ascending order according to the K stability coefficients to screen the collision-free trajectory.

[0104] The intelligent control upper pressing and lower jacking positioning pin auxiliary device provided by the embodiments of the present invention can execute the intelligent control upper pressing and lower jacking positioning pin auxiliary method provided by any embodiment of the present invention, and has the corresponding functional modules and beneficial effects for executing the method.

[0105] Although the present application makes various references to certain modules in the apparatus according to embodiments of the present application, however, any number of different modules can be used and run on the user terminal and / or server. The various units and modules included are only divided according to functional logic, but are not limited to the above division as long as the corresponding functions can be achieved. In addition, the specific names of the functional units are only for the convenience of mutual distinction and do not limit the protection scope of the present invention.

[0106] The above specific embodiments do not constitute a limitation on the protection scope of the present application. Those skilled in the art should understand that various modifications, combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present application shall be included within the protection scope of the present application. In some cases, the actions or steps recited in the present application can be executed in a different order than in the embodiments and still achieve the desired result. Additionally, the processes depicted in the drawings do not necessarily require the specific order or sequential order shown to achieve the desired result. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

Claims

1. The intelligent control upper pressing and lower jacking positioning pin auxiliary device is characterized in that, Including: A trajectory construction module, which is used to construct a collision-free trajectory through pose deviation analysis after the robotic arm grasps the target workpiece in the rough positioning area; A deviation analysis module, which is used to trigger microscopic deviation analysis after driving the robotic arm to transfer the target workpiece into the vision working area by using the collision-free trajectory, and output a trajectory compensation action and a positioning pin compensation action; A positioning pin extension module, which is used to synchronously pre-extension K electric positioning pins on the fixture base by using the positioning pin compensation action during the process of driving the robotic arm to grip the target workpiece to the force sense guidance area by using the collision-free trajectory corrected by the trajectory compensation action; A pressure parameter acquisition module, which is used to activate the force sensor to acquire the fitting pressure parameter after the robotic arm grips the target workpiece and enters the force sense guidance area and pre-fits with the K electric positioning pins; An auxiliary assembly module, which is used to perform three-force closed-loop optimization based on the fitting pressure parameter, output three-force dynamic control parameters, and assist the linkage displacement of the upper pressing mechanism, the lower jacking structure and the K electric positioning pins to perform the fixture-assisted assembly of the target workpiece.

2. The intelligent control upper pressing and lower jacking positioning pin auxiliary device according to claim 1, characterized in that, The trajectory construction module includes: A macro position point cloud data acquisition module, which is used to trigger a line laser scanner to acquire macro position point cloud data according to the grasping behavior of the robotic arm in the rough positioning area, wherein the macro position point cloud data includes H sets of non-coplanar feature points of the workpiece and the positioning pin point cloud; A rough positioning analysis module, which is used to perform rough positioning analysis according to the macro position point cloud data and output a 6-degree-of-freedom pose deviation; A collision-free trajectory construction module, which is used to construct the collision-free trajectory according to the 6-degree-of-freedom pose deviation and then start the displacement of the robotic arm gripping the workpiece.

3. The intelligent control upper pressing and lower jacking positioning pin auxiliary device according to claim 2, characterized in that, The rough positioning analysis module includes: A workpiece CAD model calling module, which is used to locally call the workpiece CAD model according to the workpiece ID of the target workpiece; A 6-degree-of-freedom pose deviation calculation module, which is used to register the macro position point cloud and the workpiece CAD model through the ICP algorithm, and calculate the 6-degree-of-freedom pose deviation of the target workpiece relative to the fixture, wherein the 6-degree-of-freedom pose deviation is composed of a translation component and a rotation component.

4. The intelligent control upper pressing and lower jacking positioning pin auxiliary device according to claim 1, characterized in that, The deviation analysis module includes: An image acquisition module, which is used to synchronously activate the main view camera and the auxiliary view camera to acquire the workpiece image and the positioning pin image after the target workpiece enters the vision working area; A feature matching module, which is used to perform edge detection and feature matching on the workpiece image and the positioning pin image respectively, and identify the K positioning hole spatial positions of the K target positioning holes on the target workpiece and the W positioning pin spatial positions of the W electric positioning pins on the fixture, wherein W is a positive integer greater than K; A neighboring positioning pin matching module, which is used to perform neighboring positioning pin matching of the K target positioning holes according to the K positioning hole spatial positions and the W positioning pin spatial positions to obtain K hole-pin matching groups; A 6-degree-of-freedom microscopic deviation calculation module, which is used to extract the K electric positioning pins from the K hole-pin matching groups, and calculate and output a 6-degree-of-freedom microscopic deviation according to the K positioning hole spatial positions and the K positioning pin spatial positions of the K electric positioning pins. The associated compensation and correction module is used to perform associated compensation and correction based on the 6-DOF micro deviation, and output the trajectory compensation action and the positioning pin compensation action.

5. The intelligent control upper pressing and lower jacking positioning pin auxiliary device according to claim 4, wherein The associated compensation and correction module includes: A 6-DOF micro deviation decomposition module, which is used to decompose the 6-DOF micro deviation to obtain a translation deviation and a rotation deviation; A fitting end correction amount calculation module, which is used to calculate the fitting end correction amount of the robotic arm according to the translation deviation; A clamping pose correction amount calculation module, which is used to calculate the clamping pose correction amount of the robotic arm according to the rotation deviation. Among them, the fitting end correction amount and the clamping pose correction amount constitute the trajectory compensation action; A positioning pin compensation calculation module, which is used to perform positioning pin compensation calculation after correcting the 6-DOF micro deviation according to the trajectory compensation action to obtain the positioning pin compensation action.

6. The intelligent control upper pressing and lower jacking positioning pin auxiliary device according to claim 5, wherein, The positioning pin compensation calculation module includes: A 6-DOF residual deviation output module, which is used to perform micro deviation correction fitting of the 6-DOF micro deviation according to the trajectory compensation action and output the 6-DOF residual deviation; A positioning pin extension amount calculation module, which is used to extract the plane deviation from the 6-DOF residual deviation to calculate the positioning pin extension amount; A bias pin rotation angle calculation module, which is used to extract the angle deviation from the 6-DOF residual deviation to calculate the bias pin rotation angle. Among them, the positioning pin extension amount and the bias pin rotation angle constitute the positioning pin compensation action.

7. The intelligent control upper pressing and lower jacking positioning pin auxiliary device according to claim 1, characterized in that, The auxiliary assembly module includes: A three-force balance condition calling module, which is used to locally call the three-force balance condition; A three-force deviation solving module, which is used to solve the three-force deviation of the fitting pressure parameter according to the three-force balance condition and output the initial three-force control parameters. Among them, the initial three-force control parameters include the upper pressing pressure, the lower supporting force, and the positioning pin contact force; A PID parameter tuning module, which is used to perform PID parameter tuning of the initial three-force control parameters according to the real-time fitting pressure and the three-force deviation of the three-force balance condition during the process of driving the linkage displacement of the upper pressing mechanism, the lower supporting structure, and the K electric positioning pins by using the initial three-force control parameters.

8. The intelligent control upper pressing and lower jacking positioning pin auxiliary device according to claim 2, characterized in that The collision-free trajectory construction module includes: An obstacle three-dimensional grid map construction module, which is used to preset the grid resolution and construct an obstacle three-dimensional grid map according to the 6-DOF pose deviation with the grid resolution as a constraint; A clamping behavior simulation module, which is used to simulate the clamping behaviors of the K alternative trajectories after searching for the K alternative trajectories in the obstacle three-dimensional grid map with collision-free as the search condition, and output K joint acceleration sequences and K clamping end velocity sequences; A clamping stability fusion evaluation module, which is used to perform clamping stability fusion evaluation according to the K joint acceleration sequences and the K clamping end velocity sequences, and screen and locate the collision-free trajectory according to the evaluation results.

9. The intelligent control upper pressing and lower jacking positioning pin auxiliary device according to claim 8, wherein, The clamping stability fusion evaluation module includes: A clamping end velocity constraint matching module, which is used to match the clamping end velocity constraint according to the mass characteristics of the target workpiece; A joint acceleration limit extraction module, which is used to retrieve and extract the joint acceleration limit according to the robotic arm ID; An acceleration deviation rate acquisition module, configured to traverse a first joint acceleration sequence by using the joint acceleration limit, so as to obtain Q acceleration deviation rates of Q acceleration deviation nodes; A weighted fusion module, configured to perform weighted fusion on the Q acceleration deviation rates according to the adjacent time differences of the Q acceleration deviation nodes, and output a first deviation feature; A second deviation feature output module, configured to, by analogy, evaluate a first gripper end velocity sequence by using the gripper end velocity, and output a second deviation feature; A first stability coefficient output module, configured to perform weighted fusion on the first deviation feature and the second deviation feature by using a preset stability weight, and output a first stability coefficient; A collision-free trajectory screening module, configured to, by analogy, perform a gripper stability fusion evaluation on the K alternative trajectories, and after outputting K stability coefficients, arrange the K alternative trajectories in ascending order according to the K stability coefficients, so as to screen the collision-free trajectories.

10. An intelligent control method for the upper pressing and lower jacking positioning pin, characterized in that, The method is implemented by an intelligent control upper pressing and lower jacking positioning pin auxiliary device according to any one of claims 1-9, and the device includes: After the robotic arm grabs a target workpiece in the rough positioning area, a collision-free trajectory is constructed through pose deviation analysis; After using the collision-free trajectory to drive the robotic arm to transfer the target workpiece into the vision working area, micro deviation analysis is triggered, and a trajectory compensation action and a positioning pin compensation action are output; During the process of driving the robotic arm to grip the target workpiece to the force sense guidance area by using the collision-free trajectory corrected by the trajectory compensation action, the positioning pin compensation action is synchronously used to pre-extend K electric positioning pins on the fixture base; After the robotic arm grips the target workpiece and enters the force sense guidance area and pre-engages with the K electric positioning pins, a force sensor is activated to collect the engagement pressure parameter; According to the engagement pressure parameter, three-force closed-loop optimization is performed, three-force dynamic control parameters are output, and the linkage displacement of the upper pressing mechanism, the lower jacking structure, and the K electric positioning pins is assisted to perform fixture-assisted assembly of the target workpiece.

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