A clamping positioning calibration control system of AGV multi-degree-of-freedom mechanical arm

Abstract

The application discloses a clamping positioning calibration control system of an AGV multi-degree-of-freedom mechanical arm and relates to the technical field of numerical control machining automation.The system comprises a workpiece centering module, a docking reference module, a coupling connection module, a synchronous conveying module and a workpiece handover module.The workpiece centering module controls the multi-degree-of-freedom mechanical arm to transfer a workpiece to a self-centering tool and coarsely centers the workpiece.The docking reference module controls the integrated end effector of the multi-degree-of-freedom mechanical arm to adsorb the workpiece and release the clamping of the self-centering tool, so that a docking reference posture is obtained.The coupling connection module controls the CNC machine tool spindle and the integrated end effector to complete rigid coaxial connection.The synchronous conveying module controls the CNC machine tool spindle and the multi-degree-of-freedom mechanical arm to perform synchronous movement, so that the workpiece is conveyed to a fixed adsorption tool.The workpiece handover module releases the workpiece after adsorbing the fixed workpiece and controls the CNC machine tool spindle and the integrated end effector to separate, so that workpiece handover is completed.The application realizes seamless closed-loop handover of the workpiece from mobile end coarse centering to fixed end spindle reference positioning.

Description

Technical Field

[0001] This invention relates to the field of CNC machining automation technology, specifically a clamping, positioning, calibration, and control system for an AGV multi-degree-of-freedom robotic arm. Background Technology

[0002] In the field of precision CNC machining, as the manufacturing industry evolves towards greater flexibility and automation, utilizing AGVs equipped with multi-degree-of-freedom robotic arms for automated loading and unloading of CNC machine tools has become a core technological path for building intelligent production lines. This technology aims to replace manual labor or fixed robotic arms, enabling high-degree-of-freedom transfer and clamping of workpieces between the hopper and the machine tool. In current mainstream loading and unloading solutions, after a regular AGV arrives at the machine tool station, it relies entirely on its onboard robotic arm to directly grab the workpiece from the pallet. Leveraging the AGV's own docking accuracy and the robotic arm's repeatability, the workpiece is placed within the fixture on the machine tool's worktable, with the positioning reference provided by the robotic arm's end effector throughout the process.

[0003] However, the existing technical solutions still have the following drawbacks: First, there are multiple sources of positioning error that accumulate at each level. The initial eccentricity of the incoming workpiece, the docking error of the AGV, and the absolute positioning error of the robotic arm joints are superimposed, resulting in a final clamping accuracy that is usually above ±0.1mm. Second, there is a fundamental mismatch in the positioning reference system. The existing solutions completely abandon the spindle reference of the CNC machine tool itself, which has a precision of up to the micrometer level, and instead rely on the lower precision of the moving robotic arm as the final positioning reference, which is like using a low-precision tool to calibrate a high-precision instrument. In addition, there is a risk of separation during process execution. The step-by-step operation of the robotic arm unloading and the tooling suction is in an unconstrained state at the moment of handover, which can easily cause slight secondary offset, impact, or deformation of the workpiece, resulting in a complete loss of control over the centering accuracy. Therefore, how to overcome the problems of large cumulative error, mismatch of positioning reference and accuracy breakpoint in the handover process in the existing technology, and realize the leap from millimeter level to micrometer level in workpiece loading and unloading positioning accuracy, so as to improve the processing yield of automated production line and the reliability of unmanned operation, is the problem we need to solve. To this end, we now provide a clamping positioning calibration control system for AGV multi-degree-of-freedom robotic arm. Summary of the Invention

[0004] The purpose of this invention is to provide a clamping, positioning, calibration, and control system for a multi-degree-of-freedom AGV robotic arm.

[0005] The objective of this invention can be achieved through the following technical solution: a gripping, positioning, calibration, and control system for an AGV multi-degree-of-freedom robotic arm, comprising:

[0006] The workpiece centering module is used to control the multi-degree-of-freedom robotic arm to grasp the workpiece and transfer the workpiece to the self-centering fixture set on the AGV body. The self-centering fixture clamps the workpiece to complete the coarse centering.

[0007] The docking reference module is used to control the integrated end effector of the multi-degree-of-freedom robotic arm to adsorb the workpiece that has been coarsely centered, and to release the clamping of the self-centering fixture to obtain the docking reference posture.

[0008] The coupling connection module is used to control the CNC machine tool spindle to dock and couple with the standard tool holder integrated on the integrated end effector in the docking reference posture, so as to complete the rigid coaxial connection.

[0009] The synchronous conveying module is used to control the CNC machine tool spindle and the multi-degree-of-freedom robotic arm to move synchronously, conveying the workpiece and attaching it to a fixed adsorption fixture set on the CNC machine tool worktable.

[0010] The workpiece handover module is used to control the integrated end effector to release the workpiece after the fixed adsorption fixture adsorbs and fixes the workpiece, and to control the CNC machine tool spindle to separate from the standard tool holder, thereby completing the workpiece handover.

[0011] Furthermore, the workpiece centering module controls the multi-degree-of-freedom robotic arm to grasp the workpiece and transfer it to a self-centering fixture mounted on the AGV body. The process of the self-centering fixture clamping the workpiece includes:

[0012] The multi-degree-of-freedom robotic arm is controlled to adsorb workpieces in a tray via the integrated end effector;

[0013] The multi-degree-of-freedom robotic arm is controlled to transfer the workpiece to the clamping area of ​​the self-centering tooling;

[0014] The integrated end effector is controlled to depressurize and release the workpiece, and the self-centering fixture is triggered to perform a clamping action. The clamping action is to complete the coarse centering by the self-centering fixture synchronously supporting the inner wall of the workpiece from the outside.

[0015] Furthermore, the process by which the docking reference module controls the integrated end effector of the multi-degree-of-freedom robotic arm to adsorb the workpiece that has completed coarse centering and release the clamping of the self-centering fixture to obtain the docking reference posture includes:

[0016] The multi-degree-of-freedom robotic arm is controlled to descend, so that the integrated end effector fits against the workpiece that has been coarsely centered, and the negative pressure adsorption is activated to lock the workpiece.

[0017] Control the self-centering tool to release and retract to the safe position;

[0018] The position information of each axis encoder of the multi-degree-of-freedom robotic arm is read, and the current posture is locked as the docking reference posture.

[0019] Furthermore, the docking reference posture is an posture in which the center of the workpiece, the center of the standard tool holder integrated on the integrated end effector, and the reference center of the self-centering tooling are aligned.

[0020] Furthermore, the coupling connection module controls the CNC machine tool spindle to dock and couple with the standard tool holder integrated on the integrated end effector, which is in the docking reference posture, to complete the rigid coaxial connection process, including:

[0021] Obtain the AGV arrival signal and control the CNC machine tool spindle to move to the waiting docking position directly above the fixed adsorption fixture;

[0022] Control the CNC machine tool spindle to feed downward along the Z-axis, so that its tapered hole is completely in contact with the tapered surface of the standard tool holder at the end of the multi-degree-of-freedom robotic arm carrying the workpiece;

[0023] The puller inside the CNC machine tool spindle is controlled to tighten and lock the standard tool holder to complete a rigid coaxial connection.

[0024] Furthermore, the coupling connection module also includes:

[0025] The synchronous communication submodule is used to enable the encoder of the CNC machine tool spindle to establish synchronous following communication with the encoder of the multi-degree-of-freedom robot arm after the rigid coaxial connection is established.

[0026] Furthermore, the synchronous conveying module controls the CNC machine tool spindle and the multi-degree-of-freedom robotic arm to move synchronously, and the process of conveying and attaching the workpiece to the fixed adsorption fixture set on the CNC machine tool worktable includes:

[0027] Based on the synchronous follow communication, the CNC machine tool spindle and the multi-degree-of-freedom robotic arm perform synchronous Z-axis downward feed in a real-time speed and displacement matching manner, so that the lower surface of the workpiece slowly adheres to the fixed adsorption fixture until the negative pressure detection of the fixed adsorption fixture reaches a preset threshold, and it is determined that the workpiece is adsorbed and fixed.

[0028] Furthermore, after the workpiece is adsorbed and fixed by the fixed adsorption fixture, the workpiece transfer module controls the integrated end effector to release the workpiece and controls the CNC machine tool spindle to separate from the standard tool holder, completing the workpiece transfer process, which includes:

[0029] After determining that the workpiece has been adsorbed and fixed, the integrated end effector is controlled to depressurize and cut off the gas supply to release the workpiece;

[0030] The puller inside the CNC machine tool spindle is released, and the CNC machine tool spindle is raised to separate from the standard tool holder.

[0031] Control the multi-degree-of-freedom robotic arm to lift and exit the machining area of ​​the CNC machine tool.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention uses a workpiece centering module to perform a first-stage coarse centering of the gripped workpiece using a self-centering fixture set on the AGV body, eliminating the original placement deviation of the incoming workpiece and the positional error introduced by the robotic arm gripping, so that the center of the workpiece coincides with the on-board reference, significantly improving the system's tolerance to upstream multi-source errors; after the AGV is in place, the coupling connection module controls the CNC machine tool spindle to dock with the standard tool holder in the docking reference posture, forming a rigid coaxial connection of "spindle-tool holder-workpiece", switching the workpiece positioning reference from the less precise robotic arm. The CNC machine tool spindle, achieving micron-level precision, fundamentally overcomes the positioning accuracy bottleneck caused by datum mismatch in traditional solutions. Through a synchronous conveying module, the CNC machine tool spindle and robotic arm move synchronously, conveying the workpiece without impact and fitting it to a fixed suction fixture. This ensures the workpiece remains constrained by the rigid coaxial connection throughout the placement process, completely eliminating secondary offsets and impacts caused by the workpiece's momentary unconstrained state in traditional step-by-step "feeding-suction" operations. This ensures the final positioning accuracy is entirely determined by the spindle datum, thereby improving the final clamping and positioning accuracy of AGV loading and unloading to the micron level. This invention achieves a seamless closed-loop transfer of the workpiece from coarse centering at the moving end to spindle datum positioning at the fixed end, solving the problem that traditional AGV loading and unloading solutions cannot meet precision machining requirements due to datum mismatch and separation during transfer. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0034] Figure 1 This is a schematic diagram of the present invention. Detailed Implementation

[0035] like Figure 1 As shown, a gripping, positioning, calibration, and control system for an AGV multi-degree-of-freedom robotic arm includes:

[0036] The workpiece centering module is used to control the multi-degree-of-freedom robotic arm to grasp the workpiece and transfer the workpiece to the self-centering fixture set on the AGV body. The self-centering fixture clamps the workpiece to complete the coarse centering.

[0037] The docking reference module is used to control the integrated end effector of the multi-degree-of-freedom robotic arm to adsorb the workpiece that has been coarsely centered, and to release the clamping of the self-centering fixture to obtain the docking reference posture.

[0038] The coupling connection module is used to control the CNC machine tool spindle to dock and couple with the standard tool holder integrated on the integrated end effector in the docking reference posture, so as to complete the rigid coaxial connection.

[0039] The synchronous conveying module is used to control the CNC machine tool spindle and the multi-degree-of-freedom robotic arm to move synchronously, conveying the workpiece and attaching it to a fixed adsorption fixture set on the CNC machine tool worktable.

[0040] The workpiece handover module is used to control the integrated end effector to release the workpiece after the fixed adsorption fixture adsorbs and fixes the workpiece, and to control the CNC machine tool spindle to separate from the standard tool holder, thereby completing the workpiece handover.

[0041] In this embodiment, the hardware architecture mainly includes an AGV on-board unit, a CNC machine tool supporting unit, and a central control and interaction center.

[0042] The AGV on-board unit includes an AGV body, a multi-degree-of-freedom robotic arm integrated on the AGV body, and a self-centering fixture fixedly mounted on the AGV body's working platform. This self-centering fixture adopts a three-jaw pneumatic internal support structure. Its core components include a rotary clamping cylinder, a crank connecting seat, three symmetrically arranged transmission cranks, three sets of guide rails, and three cylindrical jaws. The crank connecting seat evenly distributes the output torque of the rotary clamping cylinder to the three sets of transmission cranks, driving the three jaws to move radially synchronously on their respective guide rails. The geometric center of the self-centering fixture, i.e., its reference center, has been precisely calibrated using a laser interferometer and the robotic arm base coordinate system.

[0043] Meanwhile, an integrated end effector is rigidly connected to the end flange of the multi-degree-of-freedom robotic arm. This integrated end effector is formed by machining two parts in one piece: the upper part is an HSK standard tool holder that matches the CNC spindle interface, and the lower part is an adsorption end face with a vacuum cavity, i.e., the end adsorption assembly. Its key feature is that the coaxiality error between the conical axis of the HSK standard tool holder and the central axis of the lower adsorption end face is strictly guaranteed to be within 0.005mm during the manufacturing process.

[0044] The CNC machine tool supporting unit includes a CNC machine tool body, whose spindle is equipped with a standard HSK broaching mechanism with adjustable tension; and a fixed adsorption fixture set on the CNC machine tool worktable. The adsorption plane of the fixed adsorption fixture is strictly perpendicular to the Z-axis movement direction of the machine tool spindle, and the geometric center of its adsorption surface is coaxial with the spindle rotation center with a coaxiality error of no more than 0.002mm, serving as the final positioning reference for workpiece machining.

[0045] The central control and interaction center is the core for realizing multi-device collaboration, and it communicates with the AGV on-board unit and the CNC machine tool supporting unit respectively. It consists of a central control PLC and an industrial Ethernet switch, which are connected to the AGV motion controller, the robotic arm controller and the CNC numerical control center respectively via the EtherCAT protocol. The central control and interaction center is responsible for handling signal interlocking, event triggering and timing logic. For example, the next synchronous motion command will only be allowed to be executed after the AGV arrival signal, the robotic arm posture ready signal and the CNC spindle ready signal are received simultaneously.

[0046] In this embodiment, the integrated end effector, the HSK standard tool holder, and the fixed adsorption fixture together constitute a precision positioning transfer chain. The integrated end effector is the key interface connecting the movable AGV working end to the fixed CNC high-precision reference end. The integrated HSK standard tool holder employs a 1:10 short conical surface and end face dual positioning structure, ensuring million-times high repeatability accuracy when connected to the spindle. The adsorption surface of the fixed adsorption fixture is precision ground, with a flatness of [missing information]. Better than within the range This provides a near-ideal reference plane for the final placement of the workpiece.

[0047] It should be further explained that, in the specific implementation process, the workpiece centering module controls the multi-degree-of-freedom robotic arm to grasp the workpiece and transfer the workpiece to a self-centering fixture set on the AGV body. The self-centering fixture clamps the workpiece to complete the coarse centering process, which includes:

[0048] The multi-degree-of-freedom robotic arm is controlled to adsorb workpieces in a tray via the integrated end effector;

[0049] The multi-degree-of-freedom robotic arm is controlled to transfer the workpiece to the clamping area of ​​the self-centering tooling;

[0050] The integrated end effector is controlled to depressurize and release the workpiece, and the self-centering tooling is triggered to perform a clamping action. The clamping action is the coarse centering completed by the self-centering tooling synchronously supporting the inner wall of the workpiece from the outside.

[0051] Specifically, after the AGV autonomously navigates to the raw material pallet station, the central control center issues a loading command. The multi-degree-of-freedom robotic arm moves above the pallet, and the bottom surface of its integrated end effector aligns with a ring-shaped workpiece to be processed. The end-effector adsorption component is activated, reducing the absolute pressure in the vacuum chamber to a set threshold, for example, approximately 41 kPa. The formula for calculating the vacuum adsorption force is: ;in, This is the difference between the atmospheric pressure outside the end-adsorption assembly and the absolute pressure inside the vacuum chamber of the end-adsorption assembly. The effective adsorption area is the actual area of ​​contact between the end-effector and the surface of the workpiece. After the sensor detects that the negative pressure has reached the target, the robotic arm is raised, carrying the workpiece to a position directly above the self-centering fixture of the AGV body. According to the pre-calibrated coordinates, the robotic arm descends vertically, placing the workpiece onto the centering platform of the self-centering fixture, ensuring that the inner hole of the workpiece is roughly fitted into the three jaws of the self-centering fixture in the contracted state. At this time, the integrated end effector depressurizes and cuts off the air supply, releasing the workpiece and raising it upwards to avoid collisions.

[0052] Subsequently, the central control center triggers the self-centering fixture's action, activating the rotary clamping cylinder and outputting a preset torque value. Through the crank connecting seat and transmission crank, this drives the three jaws to synchronously expand radially outward along the guide rail. The jaws, with their cylindrical surface design, achieve line contact with the inner wall of the annular workpiece, automatically aligning and clamping the workpiece from the inside. During this process, the radial displacement difference between any two jaws is constrained by the mechanical structure itself to within 0.01mm, thus completing coarse centering. At this point, the geometric center axis of the workpiece is forcibly corrected to coincide with the reference center of the self-centering fixture, denoted as point [point number missing]. The workpiece centering module solves the problem of the original placement deviation of the workpiece on the pallet and the position fluctuation introduced by the robotic arm during grasping.

[0053] After coarse centering is completed, the corrected positional relationship needs to be transferred and locked to the end effector of the robotic arm. It should be further explained that, in the specific implementation process, the docking reference module controls the integrated end effector of the multi-degree-of-freedom robotic arm to adsorb the workpiece that has completed coarse centering and release the clamping of the self-centering fixture to obtain the docking reference posture. This process includes:

[0054] The multi-degree-of-freedom robotic arm is controlled to descend, so that the integrated end effector fits against the workpiece that has been coarsely centered, and the negative pressure adsorption is activated to lock the workpiece.

[0055] Control the self-centering tool to release and retract to the safe position;

[0056] The position information of the encoders of each axis of the multi-degree-of-freedom robotic arm is read, and the current posture is locked as the docking reference posture; the docking reference posture is the posture in which the center of the workpiece, the center of the standard tool holder integrated on the integrated end effector, and the reference center of the self-centering tooling are aligned.

[0057] Specifically, the central control center controls the multi-degree-of-freedom robotic arm to slowly descend again. The guide sleeve set on the side of the integrated end effector is precisely matched with the corresponding positioning pin on the self-centering tooling to provide physical guidance for the secondary gripping. When the bottom surface of the integrated end effector is completely in contact with the upper surface of the workpiece, the descent stops, the vacuum generator is restarted, negative pressure is established, and the workpiece is firmly adsorbed on the bottom of the integrated end effector.

[0058] After successful adsorption confirmation, the central control center first sends a release command to the self-centering tooling; the rotary clamping cylinder rotates in the opposite direction, driving the three jaws to retract radially in sync and return to a safe position, completely releasing the constraint on the workpiece; at this time, the workpiece is supported only by the robotic arm through the integrated end effector at a single point;

[0059] Subsequently, the central control and interaction center synchronously reads the absolute encoder values ​​of the six joints of the multi-degree-of-freedom robotic arm via the EtherCAT bus to obtain the joint space vector of the current end effector pose. This refers to a set of joint angle data that uniquely describes the current posture of the robotic arm; subsequently, the robotic arm controller calls its internally preset forward kinematics model to convert the above... The model is used as input to calculate a homogeneous transformation matrix in Cartesian space that describes the current pose of the robotic arm's end effector. The matrix This precisely represents the center of the workpiece, the center of the cone surface of the HSK standard tool holder, and the reference center of the self-centering fixture established during the previous coarse centering. The physical pose of the three elements being coaxial;

[0060] Finally, the central control center sends a command to the robotic arm controller to obtain the calculated pose matrix. Corresponding joint space vector This state is defined as the docking reference posture and stored in memory. All subsequent precision docking movements will be fine-tuned based on this posture to ensure that the established coaxial relationship is not disrupted during movement. For example, the subsequent action of feeding the HSK standard tool holder into the CNC spindle in the coupling module will be locked in this position. Using it as a reference, fine-tuning is performed by superimposing only the Z-axis translational motion on it to ensure that the established coaxial relationship is not disrupted during the movement.

[0061] After completing the baseline preparation of the AGV on-board unit, the docking phase begins. It should be further explained that, in the specific implementation process, the coupling connection module controls the CNC machine tool spindle to dock with the standard tool holder integrated on the integrated end effector, which is in the aforementioned docking baseline posture, to complete the rigid coaxial connection process, including:

[0062] Upon receiving the AGV arrival signal, control the CNC machine tool spindle to move to the waiting docking position directly above the fixed adsorption fixture;

[0063] Specifically, the AGV, equipped with a robotic arm and workpiece maintaining a docking reference posture, automatically travels to the predetermined docking station in front of the CNC machine tool. The AGV uses a lidar sensor on its vehicle to scan a reflector mounted on the side of the machine tool, precisely locking its stopping position, with the final stopping accuracy controlled within a certain range. Within; then, the AGV sends a "position signal" to the central control center; the central control center then sends a command to the CNC control center to control the CNC machine tool spindle to perform a zero-return action, and then quickly moves to the pre-programmed "waiting docking position", which is located directly above the fixed adsorption fixture; at the same time, the fixed adsorption fixture on the CNC machine tool table turns on the vacuum pump in advance to pre-pump, so that the air path is in a ready state;

[0064] The CNC machine tool spindle is controlled to feed downward along the Z-axis, so that its tapered hole is completely in contact with the tapered surface of the standard tool holder at the end of the multi-degree-of-freedom robotic arm carrying the workpiece; the Z-axis is a linear motion axis defined by the CNC machine tool worktable plane as a reference, in which the spindle moves up and down in the vertical direction;

[0065] Control the puller inside the CNC machine tool spindle to tighten and lock the standard tool holder to complete the rigid coaxial connection;

[0066] Specifically, after the central control center confirms that the AGV, robotic arm, and CNC are all in a safe interlock state, it initiates the core docking program; the robotic arm, in a locked state... Based on the orientation, the tool is translated upwards in Cartesian space, bringing the HSK standard toolholder at its end directly below the CNC spindle while keeping the tapered surface of the HSK standard toolholder vertically upwards. Then, the CNC control center controls the spindle at an extremely low feed rate, such as... The CNC spindle descends slowly along the Z-axis; its inner taper hole first contacts the tapered surface of the HSK standard tool holder. Guided by the tapered surface, the two automatically align. When the gap between the spindle end face and the HSK standard tool holder flange end face reaches a preset value, the disc spring inside the spindle drives the pull claw to firmly tighten the pull stud of the HSK standard tool holder. The tightening force reaches a preset threshold. At this point, a rigid coaxial connection without any play, namely the "spindle-tool holder-workpiece" chain, is officially established; the positioning reference has been completely switched from the robotic arm to the CNC machine tool spindle.

[0067] It should be noted that the coupling connection module further includes:

[0068] The synchronous communication submodule is used to enable the encoder of the CNC machine tool spindle to establish synchronous following communication with the encoder of the multi-degree-of-freedom robot arm after the rigid coaxial connection is established.

[0069] Specifically, the central control center sends configuration instructions to both the CNC numerical control center and the multi-degree-of-freedom robotic arm controller. The instructions clearly define: the Z-axis of the CNC machine tool spindle is set as the main motion axis, and the real-time position value fed back by its encoder is used as the synchronization reference; the Z-axis motion of the robotic arm end effector in its workpiece coordinate system is set as the slave motion axis, and it moves synchronously with the main motion axis.

[0070] The central control interaction center establishes a synchronous data mapping table internally, establishing a periodic data mapping relationship between the address of the CNC spindle Z-axis position register and the address of the corresponding workpiece coordinate system Z-axis instruction register in the robotic arm controller, thus determining the synchronous execution mechanism. The specific implementation of this data mapping is as follows: the central control interaction center polls the CNC control center at a fixed communication cycle to read the actual position value of the spindle Z-axis. After reading the latest position, the central control interaction center writes this position value as the target position instruction into the Z-axis position instruction register of the multi-degree-of-freedom robotic arm controller within the same communication cycle. Upon receiving the new target position instruction, the robotic arm controller immediately drives its Z-axis motor to move to the instructed position. Therefore, the real-time position of the robotic arm Z-axis always remains consistent with the real-time position of the spindle Z-axis, and the following error between the two is controlled within a preset safety threshold, for example... Physically, it achieves millisecond-level synchronous following motion between the end effector of the robotic arm and the CNC spindle.

[0071] After the positioning reference is switched from the robotic arm to the CNC machine tool spindle, the workpiece needs to be placed on the fixed adsorption fixture without disturbance. It should be further explained that, in the specific implementation process, the synchronous conveying module controls the CNC machine tool spindle and the multi-degree-of-freedom robotic arm to move synchronously, conveying the workpiece without impact and fitting it onto the fixed adsorption fixture set on the CNC machine tool worktable. This process includes:

[0072] Based on the synchronous follow communication, the CNC machine tool spindle and the multi-degree-of-freedom robotic arm perform synchronous Z-axis downward feed in a real-time speed and displacement matching manner, so that the lower surface of the workpiece slowly adheres to the fixed adsorption fixture until the negative pressure detection of the fixed adsorption fixture reaches a preset threshold, and it is determined that the workpiece is adsorbed and fixed.

[0073] Specifically, the central control center simultaneously sends synchronous motion commands to both the CNC control center and the robotic arm controller; these commands set a common target displacement. This refers to the vertical distance from the current workpiece position to the surface required for it to adhere to the fixed adsorption fixture; this distance has been precisely measured and programmed in advance. The movement of the CNC spindle along the Z-axis and the Z-axis movement of the end effector of the multi-degree-of-freedom robotic arm in the workpiece coordinate system are at the same speed and magnitude. With the same acceleration for downward feed, the relative velocity between the two in the Z-direction is zero.

[0074] During the movement, the central control interaction center polls and reads the actual Z-axis position values ​​fed back by the CNC numerical control center and the multi-degree-of-freedom robotic arm controller at a fixed communication cycle of 1kHz, and compares them; if any position following error exceeds a preset synchronization threshold, for example... The motion is immediately stopped and an alarm is triggered to prevent the workpiece from being stretched or squeezed and deformed. This synchronous motion control ensures that the entire rigidly connected "spindle-tool holder-workpiece" assembly moves smoothly downward as a whole. The lower surface of the workpiece slowly and evenly approaches the adsorption plane of the fixed adsorption fixture.

[0075] Once the lower surface of the workpiece is fully in contact with the adsorption plane of the fixed adsorption fixture, the CNC spindle and robotic arm immediately stop feeding. At this point, the high-precision vacuum pressure sensor in the air circuit of the fixed adsorption fixture detects a sharp drop in pressure that stabilizes below a set threshold, for example, an absolute pressure below 21 kPa, and continues to do so. If the workpiece is reliably adsorbed, the final positioning is completed. At this point, the final positional accuracy of the workpiece is no longer affected by any cumulative error of the AGV and the robotic arm. It is entirely determined by the high-precision assembly datum of the machine tool spindle and the fixed adsorption fixture. Its planar fit and center coaxiality both reach the micron level.

[0076] After determining that the workpiece is adsorbed and fixed, separation from the integrated end effector is achieved. It should be further explained that, in the specific implementation process, after the workpiece is adsorbed and fixed by the fixed adsorption fixture, the workpiece transfer module controls the integrated end effector to release the workpiece and controls the CNC machine tool spindle to separate from the standard tool holder, completing the workpiece transfer process including:

[0077] After determining that the workpiece has been adsorbed and fixed, the integrated end effector is controlled to depressurize and cut off the gas supply to release the workpiece;

[0078] The puller inside the CNC machine tool spindle is released, and the CNC machine tool spindle is raised to separate from the standard tool holder.

[0079] Control the multi-degree-of-freedom robotic arm to lift and exit the machining area of ​​the CNC machine tool;

[0080] Specifically, after the central control center receives the signal that the fixed adsorption fixture has "adsorbed in place," it executes a strict timing logic. First, a release command is sent to the integrated end effector, the end adsorption component is cut off and connected to the atmosphere, and the pressure in the vacuum chamber inside the actuator returns to normal pressure, instantly releasing the upper adsorption constraint on the workpiece. This action occurs after the fixed adsorption fixture has firmly adsorbed the workpiece, ensuring that there is no risk of zero-degree-of-freedom loss of control of the workpiece at the moment of handover.

[0081] Subsequently, the central control center sends instructions to the CNC control center to activate the hydraulically or pneumatically driven tool release device inside the CNC machine tool spindle. This device overcomes the force of the disc spring, causing the pull jaws to open and release the pull stud of the HSK standard tool holder. Then, the CNC spindle moves at rapid traverse speed as follows: It rises upward along the Z-axis, completely separating from the HSK standard tool holder;

[0082] Finally, the central control center sends a retreat command to the multi-degree-of-freedom robotic arm; the robotic arm, maintaining its posture with the integrated end effector, smoothly exits from the machine tool's processing area along a pre-planned safe path; after the robotic arm has completely exited and reached a safe position, the CNC machine tool closes the protective door, starts the processing program, and grinds or mills the precisely positioned workpiece; thus, a complete, high-precision automated loading and unloading cycle is completed.

[0083] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any modifications or equivalent substitutions made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A gripping, positioning, calibration, and control system for a multi-degree-of-freedom AGV robotic arm, characterized in that, include: The workpiece centering module is used to control the multi-degree-of-freedom robotic arm to grasp the workpiece and transfer the workpiece to the self-centering fixture set on the AGV body. The self-centering fixture clamps the workpiece to complete the coarse centering. The docking reference module is used to control the integrated end effector of the multi-degree-of-freedom robotic arm to adsorb the workpiece that has been coarsely centered, and to release the clamping of the self-centering fixture to obtain the docking reference posture. The coupling connection module is used to control the CNC machine tool spindle to dock and couple with the standard tool holder integrated on the integrated end effector in the docking reference posture, so as to complete the rigid coaxial connection. The synchronous conveying module is used to control the CNC machine tool spindle and the multi-degree-of-freedom robotic arm to move synchronously, conveying the workpiece and attaching it to a fixed adsorption fixture set on the CNC machine tool worktable. The workpiece handover module is used to control the integrated end effector to release the workpiece after the fixed adsorption fixture adsorbs and fixes the workpiece, and to control the CNC machine tool spindle to separate from the standard tool holder, thereby completing the workpiece handover.

2. The gripping, positioning, calibration, and control system for an AGV multi-degree-of-freedom robotic arm according to claim 1, characterized in that, The workpiece centering module controls the multi-degree-of-freedom robotic arm to grasp the workpiece and transfer it to a self-centering fixture mounted on the AGV body. The process of the self-centering fixture clamping the workpiece includes: The multi-degree-of-freedom robotic arm is controlled to adsorb workpieces in a tray via the integrated end effector; The multi-degree-of-freedom robotic arm is controlled to transfer the workpiece to the clamping area of ​​the self-centering tooling; The integrated end effector is controlled to depressurize and release the workpiece, and the self-centering fixture is triggered to perform a clamping action. The clamping action is to complete the coarse centering by the self-centering fixture synchronously supporting the inner wall of the workpiece from the outside.

3. The gripping, positioning, calibration, and control system for an AGV multi-degree-of-freedom robotic arm according to claim 1, characterized in that, The process by which the docking reference module controls the integrated end effector of the multi-degree-of-freedom robotic arm to adsorb the workpiece that has been coarsely centered and release the clamping of the self-centering fixture to obtain the docking reference posture includes: The multi-degree-of-freedom robotic arm is controlled to descend, so that the integrated end effector fits against the workpiece that has been coarsely centered, and the negative pressure adsorption is activated to lock the workpiece. Control the self-centering tool to release and retract to the safe position; The position information of each axis encoder of the multi-degree-of-freedom robotic arm is read, and the current posture is locked as the docking reference posture.

4. The gripping, positioning, calibration, and control system for an AGV multi-degree-of-freedom robotic arm according to claim 3, characterized in that, The docking reference posture is the posture in which the center of the workpiece, the center of the standard tool holder integrated on the integrated end effector, and the reference center of the self-centering tooling are aligned.

5. The gripping, positioning, calibration, and control system for an AGV multi-degree-of-freedom robotic arm according to claim 1, characterized in that, The coupling connection module controls the CNC machine tool spindle to dock and couple with the standard tool holder integrated on the integrated end effector, which is in the docking reference posture, to complete the rigid coaxial connection process, including: Obtain the AGV arrival signal and control the CNC machine tool spindle to move to the waiting docking position directly above the fixed adsorption fixture; Control the CNC machine tool spindle to feed downward along the Z-axis, so that its tapered hole is completely in contact with the tapered surface of the standard tool holder at the end of the multi-degree-of-freedom robotic arm carrying the workpiece; The puller inside the CNC machine tool spindle is controlled to tighten and lock the standard tool holder to complete a rigid coaxial connection.

6. The gripping, positioning, calibration, and control system for an AGV multi-degree-of-freedom robotic arm according to claim 5, characterized in that, The coupling connection module further includes: The synchronous communication submodule is used to enable the encoder of the CNC machine tool spindle to establish synchronous following communication with the encoder of the multi-degree-of-freedom robot arm after the rigid coaxial connection is established.

7. The gripping, positioning, calibration, and control system for an AGV multi-degree-of-freedom robotic arm according to claim 6, characterized in that, The synchronous conveying module controls the CNC machine tool spindle and the multi-degree-of-freedom robotic arm to move synchronously, and the process of conveying the workpiece and attaching it to the fixed adsorption fixture set on the CNC machine tool worktable includes: Based on the synchronous follow communication, the CNC machine tool spindle and the multi-degree-of-freedom robotic arm perform synchronous Z-axis downward feed in a real-time speed and displacement matching manner, so that the lower surface of the workpiece slowly adheres to the fixed adsorption fixture until the negative pressure detection of the fixed adsorption fixture reaches a preset threshold, and it is determined that the workpiece is adsorbed and fixed.

8. The gripping, positioning, calibration, and control system for an AGV multi-degree-of-freedom robotic arm according to claim 1, characterized in that, After the workpiece transfer module has attracted and fixed the workpiece using the fixed adsorption fixture, it controls the integrated end effector to release the workpiece and controls the CNC machine tool spindle to separate from the standard tool holder, thus completing the workpiece transfer process. After determining that the workpiece has been adsorbed and fixed, the integrated end effector is controlled to depressurize and cut off the gas supply to release the workpiece; The puller inside the CNC machine tool spindle is released, and the CNC machine tool spindle is raised to separate from the standard tool holder. Control the multi-degree-of-freedom robotic arm to lift and exit the machining area of ​​the CNC machine tool.

Images