Angle-adjustable industrial robot mechanical arm tail end clamping method and system

Abstract

The invention provides an angle-adjustable industrial robot mechanical arm tail end clamping method and system. The angle-adjustable industrial robot mechanical arm tail end clamping method comprises the following steps that workpiece feature scanning is conducted; generating a clamping strategy; pre-positioning the clamping unit; self-adaptive closed clamping is carried out; dynamic locking and monitoring are carried out; carrying out real-time adjustment in the transfer process; accurate release is carried out; the clamping unit is replaced; a step of carrying out system self-calibration; and carrying out fault diagnosis and recovery. The invention provides a dynamic angle adjustment clamping method based on multi-sensor feedback, and solves the existing problems through the following core innovations: a double-axis angle adjustment mechanism: synchronously adjusting a pitch angle (alpha axis) and a yaw angle (beta axis) of a clamping jaw in an initial clamping stage, so that a clamping surface is adaptively attached to a curved surface of a workpiece; force-position mixed control is conducted, specifically, a pressure distribution sensor and a proximity sensor are combined, and the clamping angle and force are optimized in real time; the modular clamping unit supports rapid replacement of clamping plates and is compatible with special-shaped workpieces.

Description

Technical Field

[0001] This invention specifically relates to an adjustable-angle end-effector gripping method and system for industrial robot arms. Background Technology

[0002] The following challenges currently exist in the field of industrial processing technology:

[0003] Poor clamping adaptability: Traditional grippers (such as parallel two-finger structures) can only open and close along a fixed trajectory and cannot dynamically adjust the clamping angle according to the workpiece's geometry. For example, in bearing assembly scenarios, rigid grippers are prone to scratching curved workpiece surfaces or uneven clamping force, leading to detachment.

[0004] Insufficient compatibility with multiple workpieces: Existing technologies (such as CN215968829U) require custom-designed grippers for workpieces of different sizes, which is time-consuming and costly to replace. For example, cylindrical workpieces and irregularly shaped workpieces require separate clamping mechanisms, resulting in low versatility.

[0005] Lack of real-time adjustment capability: Pneumatic or lead screw driven grippers (such as CN21025617U) rely on preset programs and cannot dynamically correct angles during clamping. Lead screws are prone to wear over long-term use, leading to a decrease in positioning accuracy.

[0006] Risk of damage to precision workpieces: Rigid contact can easily damage thin-walled parts (such as 0.1mm thick circuit boards). Although existing flexible grippers (such as pneumatic soft grippers) reduce collisions, they lack force control and angle coordination mechanisms, and there is still a problem of excessive deformation.

[0007] In summary, this application proposes an adjustable-angle end-effector gripping method and system for industrial robots to solve the above-mentioned problems. Summary of the Invention

[0008] The purpose of this invention is to address the shortcomings of existing technologies by providing an adjustable-angle end-effector gripping method for industrial robot arms, which can effectively solve the aforementioned problems.

[0009] To achieve the above requirements, the technical solution adopted by the present invention is: to provide an adjustable-angle end effector gripping method for an industrial robot arm, the adjustable-angle end effector gripping method for an industrial robot arm comprising the following steps:

[0010] S1: Steps for performing workpiece feature scanning;

[0011] S2: Steps for generating the clamping strategy;

[0012] S3: Step for pre-positioning the clamping unit;

[0013] S4: Steps for adaptive closed clamping;

[0014] S5: Steps for dynamic locking and monitoring;

[0015] S6: Steps for real-time adjustment of the transfer process;

[0016] S7: Steps for precise release;

[0017] S8: Steps for replacing the clamping unit;

[0018] S9: Steps for performing system self-calibration;

[0019] S10: Steps for fault diagnosis and recovery.

[0020] Preferably, step S1 specifically includes:

[0021] The workpiece point cloud data is acquired by a 3D vision sensor to identify its geometric center, radius of curvature and surface material characteristics. During scanning, the end of the robotic arm moves in a circle around the workpiece. The laser rangefinder collects distance data and fits the three-dimensional model. If the workpiece is symmetrical, the maximum outer diameter section is extracted first; if it is an irregular part, the key clamping points are marked.

[0022] Preferably, step S2 specifically includes:

[0023] Based on the output of S1, the optimal clamping pattern is matched from the policy library:

[0024] The cylinder adopts "double-point contact + tangential clamping", and the clamping angle α is initially set to 5°–10° deflection of the workpiece's cut surface perpendicular to the line.

[0025] Thin-walled parts adopt "surface contact + low-pressure closed loop", with initial clamping force ≤1N and α angle dynamic tracking of workpiece deformation;

[0026] The irregular body adopts "multi-point envelope + adaptive locking", and the fitting angle is adjusted in 10° segments along the β axis.

[0027] Preferably, step S3 specifically includes:

[0028] The α / β axis servo motors are driven to align the normal of the clamping plate with the curvature center of the target clamping point on the workpiece. The β axis rotation range is ±90°, used to compensate for the positional error of the robotic arm's end effector; the α axis tilt angle range is 0°–45°, used to optimize the pressure distribution on the contact surface; a proximity sensor monitors the distance between the clamping plate and the workpiece in real time, with a threshold set to 2mm.

[0029] Preferably, step S4 specifically includes:

[0030] The two clamping plates move toward each other at a speed of 5 mm / s, simultaneously performing angle fine-tuning and flexible buffering.

[0031] For fine-tuning of the angle, the piezoelectric thin film sensor provides feedback on the contact pressure distribution. If the pressure on one side is greater than 20% of the average, then the β-axis is compensated in reverse by 0.5°.

[0032] Flexible buffers absorb the initial contact impact, preventing rigid collisions.

[0033] Preferably, step S5 specifically includes:

[0034] Clamping force is applied according to material grade: 20–50 N for metal parts, and 5–15 N for plastic parts. The clamping plate position is locked when the pressure sensor detects the target threshold. If oil stains are present on the workpiece surface, the α angle is increased to 15°–20° to improve anti-slip capability.

[0035] Preferably, step S6 specifically includes:

[0036] A six-axis inertial sensor monitors the workpiece acceleration. If the vibration amplitude is greater than 0.5g, the clamping force is increased by 10% and the α-axis is triggered to compensate for the vibration phase angle. If the vibration continues to exceed the limit, the safety brake is activated to adsorb the workpiece.

[0037] Preferably, step S7 specifically includes:

[0038] The clamping plate detaches in two stages. First, it is loosened at a speed of 2mm / s to a gap of 1mm, and paused for 0.5 seconds to confirm the stability of the workpiece. Then, it is fully opened to a safe distance, and the proximity sensor verifies the detachment status. If it is stuck, the β-axis oscillates ±3° to break the static electricity.

[0039] Preferably, step S8 specifically includes:

[0040] Press the latches on the side wall of the clamping plate to release the mechanical lock on the guide rod. When a new clamping plate is inserted, the magnetic encoder automatically identifies the type and loads the preset parameter library;

[0041] Preferably, step S9 specifically includes: performing the following before the daily task: zeroing the α / β axis, setting and clearing the pressure sensor, calibrating the 3D vision calibration board, writing the compensation value into the historical database, and predicting the wear trend of the component.

[0042] Step S10 specifically includes:

[0043] When the force sensor data conflicts with the displacement data, a three-level response is triggered:

[0044] Primary: The elastic element is pre-compressed to release the rebound force;

[0045] Intermediate: β-axis reciprocating motion 5° to break through the bottleneck;

[0046] Advanced: Unlock the electromagnetic brake when power is off.

[0047] An adjustable-angle end-effector gripping system for an industrial robot arm is provided, using any of the aforementioned adjustable-angle end-effector gripping methods for industrial robot arms.

[0048] The advantages of this adjustable-angle industrial robot end-effector gripping method are as follows:

[0049] Improved versatility: Adaptable to regular / irregularly shaped workpieces with diameters of 5–200mm, reducing the cost of custom grippers by more than 50%;

[0050] Precision assurance: Dynamic angle adjustment accuracy ±0.1°, force control resolution 0.01N, and workpiece damage rate reduced to 0.5%;

[0051] Efficiency optimization: Clamping posture self-adjustment time <0.2 seconds, production line changeover time reduced from 30 minutes to 2 minutes;

[0052] Easy maintenance: The modular design allows for live replacement of clamping units, reducing downtime by 80%. Attached Figure Description

[0053] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, use the same reference numerals to denote the same or similar parts. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0054] Figure 1 A schematic flowchart of an adjustable-angle industrial robot end effector gripping method according to an embodiment of this application is shown. Detailed Implementation

[0055] To make the objectives, technical solutions and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and specific embodiments.

[0056] In the following description, references to "an embodiment," "an embodiment," "an example," "example," etc., indicate that the described embodiment or example may include a particular feature, structure, characteristic, property, element, or limitation, but not every embodiment or example necessarily includes that particular feature, structure, characteristic, property, element, or limitation. Furthermore, the repeated use of the phrase "an embodiment according to this application," while possibly referring to the same embodiment, does not necessarily refer to the same embodiment.

[0057] For simplicity, certain technical features known to those skilled in the art are omitted in the following description.

[0058] According to one embodiment of this application, an adjustable-angle end effector gripping method for an industrial robot arm is provided, such as... Figure 1 As shown, it includes the following steps:

[0059] S1: Steps for performing workpiece feature scanning;

[0060] S2: Steps for generating the clamping strategy;

[0061] S3: Step for pre-positioning the clamping unit;

[0062] S4: Steps for adaptive closed clamping;

[0063] S5: Steps for dynamic locking and monitoring;

[0064] S6: Steps for real-time adjustment of the transfer process;

[0065] S7: Steps for precise release;

[0066] S8: Steps for replacing the clamping unit;

[0067] S9: Steps for performing system self-calibration;

[0068] S10: Steps for fault diagnosis and recovery.

[0069] According to one embodiment of this application, step S1 of the adjustable-angle industrial robot end effector gripping method specifically includes:

[0070] Workpiece point cloud data is acquired using a 3D vision sensor to identify its geometric center, radius of curvature, and surface material characteristics. During scanning, the end effector of the robotic arm moves in a circle around the workpiece (radius 30–50 cm), and a laser rangefinder collects distance data and fits it to a 3D model. If the workpiece is symmetrical (such as a bearing), the largest outer diameter section is extracted first; if it is an irregularly shaped part (such as an engine connecting rod), key clamping points (such as the center of gravity projection surface) are marked.

[0071] According to one embodiment of this application, step S2 of the adjustable-angle industrial robot end effector gripping method specifically includes:

[0072] Based on the output of S1, the optimal clamping pattern is matched from the policy library:

[0073] The cylinder adopts "double-point contact + tangential clamping", and the clamping angle α is initially set to 5°–10° deflection of the workpiece's cut surface perpendicular to the line.

[0074] Thin-walled parts adopt "surface contact + low-pressure closed loop", with initial clamping force ≤1N and α angle dynamic tracking of workpiece deformation;

[0075] The irregular body adopts "multi-point envelope + adaptive locking", and the fitting angle is adjusted in 10° segments along the β axis.

[0076] According to one embodiment of this application, step S3 of the adjustable-angle industrial robot end effector gripping method specifically includes:

[0077] The α / β axis servo motors (accuracy 0.01°) are driven to align the normal of the clamping plate with the center of curvature of the target clamping point on the workpiece. The β axis rotation range is ±90° to compensate for end-effector pose errors; the α axis tilt angle range is 0°–45° to optimize the pressure distribution on the contact surface. A proximity sensor monitors the distance between the clamping plate and the workpiece in real time, with a threshold set at 2mm.

[0078] According to one embodiment of this application, step S4 of the adjustable-angle industrial robot end effector gripping method specifically includes:

[0079] The two clamping plates move toward each other at a speed of 5 mm / s, simultaneously performing angle fine-tuning and flexible buffering.

[0080] For fine-tuning of the angle, the piezoelectric thin film sensor (resolution 0.1 kPa) provides feedback on the contact pressure distribution. If the pressure on one side is greater than 20% of the average, then the β-axis is compensated in reverse by 0.5°.

[0081] Flexible buffer, elastic element (stiffness coefficient 50N / mm) absorbs the initial contact impact and avoids rigid collision.

[0082] According to one embodiment of this application, step S5 of the adjustable-angle industrial robot end effector gripping method specifically includes:

[0083] Clamping force is applied according to material grade: 20–50 N for metal parts, 5–15 N for plastic parts. The clamping plate position is locked when the pressure sensor detects the target threshold. If oil stains are present on the workpiece surface (coefficient of friction <0.1), the α angle is increased to 15°–20° to improve anti-slip capability.

[0084] According to one embodiment of this application, step S6 of the adjustable-angle industrial robot end effector gripping method specifically includes:

[0085] The six-axis inertial sensor monitors the workpiece acceleration. If the vibration amplitude is greater than 0.5g (such as when the robotic arm stops suddenly), the clamping force is increased by 10% and the α-axis is triggered to compensate for the vibration phase angle. If the vibration continues to exceed the limit, the safety brake is activated to adsorb the workpiece.

[0086] According to one embodiment of this application, step S7 of the adjustable-angle industrial robot end effector gripping method specifically includes:

[0087] The clamping plate detaches in two stages. First, it is loosened at a speed of 2mm / s to a gap of 1mm, and paused for 0.5 seconds to confirm the stability of the workpiece. Then, it is fully opened to a safe distance, and the proximity sensor verifies the detachment status. If it is stuck (such as by vacuum adsorption), the β-axis oscillates ±3° to break the static electricity.

[0088] According to one embodiment of this application, step S8 of the adjustable-angle industrial robot end effector gripping method specifically includes:

[0089] Press the latches on the side wall of the clamping plate to release the mechanical lock on the guide rod. When a new clamping plate is inserted, the magnetic encoder automatically identifies the type and loads the preset parameter library (such as the anti-slip coefficient of the rubber pad).

[0090] Step S9 specifically includes: Before each daily task, the following steps are performed: zeroing the α / β axes, setting and zeroing the pressure sensors, and calibrating the 3D vision calibration board. Compensation values ​​are written to the historical database to predict component wear trends.

[0091] Step S10 specifically includes:

[0092] When the force sensor data conflicts with the displacement data (e.g., the clamping plate jams), a three-level response is triggered:

[0093] Primary: The elastic element is pre-compressed to release the rebound force;

[0094] Intermediate: β-axis reciprocating motion 5° to break through the bottleneck;

[0095] Advanced: Unlock the electromagnetic brake when power is off.

[0096] According to one embodiment of this application, an adjustable-angle industrial robot end effector gripping system is provided, using any of the above-described adjustable-angle industrial robot end effector gripping methods.

[0097] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A method for end-effector gripping of an industrial robot with an adjustable angle, characterized in that, Includes the following steps: S1: Steps for performing workpiece feature scanning; S2: Steps for generating the clamping strategy; S3: Step for pre-positioning the clamping unit; S4: Steps for adaptive closed clamping; S5: Steps for dynamic locking and monitoring; S6: Steps for real-time adjustment of the transfer process; S7: Steps for precise release; S8: Steps for replacing the clamping unit; S9: Steps for performing system self-calibration; S10: Steps for fault diagnosis and recovery.

2. The adjustable-angle industrial robot end effector gripping method according to claim 1, characterized in that, Step S1 specifically includes: The workpiece point cloud data is acquired by a 3D vision sensor to identify its geometric center, radius of curvature and surface material characteristics. During scanning, the end of the robotic arm moves in a circle around the workpiece. The laser rangefinder collects distance data and fits the three-dimensional model. If the workpiece is symmetrical, the maximum outer diameter section is extracted first; if it is an irregular part, the key clamping points are marked.

3. The adjustable-angle industrial robot end effector gripping method according to claim 1, characterized in that, Step S2 specifically includes: Based on the output of S1, the optimal clamping pattern is matched from the policy library: The cylinder adopts "double-point contact + tangential clamping", and the clamping angle α is initially set to 5°–10° deflection of the workpiece's cut surface perpendicular to the line. Thin-walled parts adopt "surface contact + low-pressure closed loop", with initial clamping force ≤1N and α angle dynamic tracking of workpiece deformation; The irregular body adopts "multi-point envelope + adaptive locking", and the fitting angle is adjusted in 10° segments along the β axis.

4. The adjustable-angle industrial robot end effector gripping method according to claim 1, characterized in that, Step S3 specifically includes: The α / β axis servo motors are driven to make the normal of the clamping plate coincide with the curvature center of the workpiece target clamping point. The β axis rotation range is ±90°, which is used to compensate for the positional error of the robotic arm end effector. The α axis tilt angle range is 0°–45°, which is used to optimize the pressure distribution on the contact surface. The proximity sensor monitors the distance between the clamping plate and the workpiece in real time, with a threshold set to 2mm.

5. The adjustable-angle industrial robot end effector gripping method according to claim 1, characterized in that, Step S4 specifically includes: The two clamping plates move toward each other at a speed of 5 mm / s, simultaneously performing angle fine-tuning and flexible buffering. For fine-tuning of the angle, the piezoelectric thin film sensor provides feedback on the contact pressure distribution. If the pressure on one side is greater than 20% of the average, then the β-axis is compensated in reverse by 0.5°. Flexible buffers absorb the initial contact impact, preventing rigid collisions.

6. The adjustable-angle industrial robot end effector gripping method according to claim 1, characterized in that, Step S5 specifically includes: Clamping force is applied according to material grade: 20–50N for metal parts and 5–15N for plastic parts. When the pressure sensor detects the target threshold, the clamping plate position is locked. If there are oil stains on the workpiece surface, the α angle is increased to 15°–20° to improve the anti-slip capability.

7. The adjustable-angle industrial robot end effector gripping method according to claim 1, characterized in that, Step S6 specifically includes: A six-axis inertial sensor monitors the workpiece acceleration. If the vibration amplitude is greater than 0.5g, the clamping force is increased by 10% and the α-axis is triggered to compensate for the vibration phase angle. If the vibration continues to exceed the limit, the safety brake is activated to adsorb the workpiece.

8. The adjustable-angle end-effector gripping method for an industrial robot arm according to claim 1, characterized in that, Step S7 specifically includes: The clamping plate detaches in two stages. First, it is loosened at a speed of 2mm / s to a gap of 1mm, and paused for 0.5 seconds to confirm the stability of the workpiece. Then, it is fully opened to a safe distance, and the proximity sensor verifies the detachment status. If it is stuck, the β-axis oscillates ±3° to break the static electricity.

9. The adjustable-angle industrial robot end effector gripping method according to claim 1, characterized in that, Step S8 specifically includes: Press the latches on the side wall of the clamping plate to release the mechanical lock on the guide rod. When a new clamping plate is inserted, the magnetic encoder automatically identifies the type and loads the preset parameter library; Step S9 specifically includes: performing the following before the daily task: α / β axis zeroing, pressure sensor zeroing, 3D vision calibration plate calibration, compensation value writing to historical database, and predicting component wear trend. Step S10 specifically includes: When the force sensor data conflicts with the displacement data, a three-level response is triggered: Primary: The elastic element is pre-compressed to release the rebound force; Intermediate: β-axis reciprocating motion 5° to break through the bottleneck; Advanced: Unlock the electromagnetic brake when power is off.

10. An adjustable-angle end effector gripping system for an industrial robot arm, characterized in that, The adjustable-angle end effector gripping method for an industrial robot arm as described in any one of claims 1 to 9.

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