A visual perception-based parallel engraving robot and a control method thereof

Abstract

The application relates to a visual perception-based parallel engraving robot and a control method thereof, which comprises a frame support, a parallel mechanism and a work platform, the parallel mechanism comprises four driving branches, an intermediate constraint branch and a moving platform, the first and third driving branches in the parallel mechanism are completely identical and comprise a linear module sliding table, a rotary pair and a Hooke joint, one end of the linear module sliding table is connected with the rotary pair, and the other end is connected with the moving platform through the Hooke joint; the second and fourth driving branches are completely identical and comprise a Hooke joint, a servo electric cylinder and a rotary pair, one end of the servo electric cylinder is connected with the frame, and the other end is connected with the moving platform; the intermediate constraint branch chain comprises two rotary pairs and a sliding device and is sequentially connected with the frame and the moving platform through the rotary pairs. The application is fused through redundant driving, force-position hybrid control, visual perception and sliding mode control, effectively reduces the vibration phenomenon, improves the system precision and robustness, and has a wide application prospect.

Description

Technical Field

[0001] This invention relates to parallel robots, visual perception technology, and sliding mode control technology, specifically to a visual perception-based parallel carving robot and its control method for machining high-precision complex curved surface parts. Background Technology

[0002] With the rapid development of industrial automation and intelligent manufacturing technologies, engraving robots are being used more and more widely in the field of precision manufacturing, especially parallel robots. Parallel robots, due to their superior rigidity, high precision, and strong load-bearing capacity, have become important tools in high-precision engraving, cutting, and machining tasks. However, existing engraving robot systems, whether based on serial or parallel structures, still face technical challenges such as difficulty in precision control, adjustment of the relative position of the workpiece and tool, and susceptibility to vibration and errors during machining.

[0003] In the field of parallel robots, some research has focused on improving robot accuracy and adaptability by introducing visual perception technology, particularly visual feedback-based control methods. Existing parallel robot systems utilize cameras and image recognition technology to monitor the relative position between the tool and workpiece in real time, dynamically adjusting the robot's trajectory through closed-loop control. The system analyzes errors by extracting image features and edge information, and corrects the robot's position promptly. However, existing visual perception systems are typically limited to static position measurement and image recognition, and remain insufficient for precise control during dynamic machining processes, failing to effectively address complex three-dimensional spatial errors and external disturbances. Therefore, although some visual perception systems have been applied to carving robots, they generally suffer from the problems of relying on a single visual input and lacking comprehensive real-time perception of the dynamic environment.

[0004] To overcome the shortcomings of existing technologies, this invention proposes a parallel carving robot based on a visual perception sensor and its control method. This method can acquire the position information and attitude parameters of the moving platform in real time. By introducing a robust sliding mode control algorithm, the system can effectively resist the influence of external disturbances and uncertainties, while effectively suppressing chatter during processing. This significantly improves the working accuracy of the parallel carving robot, especially in dynamic processing and complex environments, where it exhibits higher robustness and adaptability, thus overcoming the limitations of existing technologies in dynamic precision control and environmental perception. Summary of the Invention

[0005] This invention provides a vision-based parallel carving robot and its control method. It aims to significantly improve carving accuracy and processing efficiency by introducing vision-based perception technology to acquire motion parameters of the moving platform in real time and dynamically monitor and optimize the robot's motion trajectory and tool position during the carving process. This invention not only overcomes the accuracy problems caused by measurement errors of traditional sensors but also provides real-time feedback on dynamic processing and corrects errors in real time, effectively improving the stability and robustness of workpiece processing. By introducing a sliding mode control algorithm, the system's resistance to external disturbances and uncertainties is enhanced, and chatter during processing is suppressed, ensuring the sustainability of high-precision carving. This invention is implemented using the following technical solutions:

[0006] A vision-based parallel carving robot, characterized by comprising a frame support, a parallel mechanism, and a work platform, wherein an industrial camera is mounted on the frame support, and the parallel mechanism comprises four drive branches, an intermediate constraint branch, and a moving platform. The first and third drive branches each include a linear module slide, a revolute joint, a support body, and a Hooke hinge. The linear module slide includes a servo motor, a motor bracket, a coupling, a ball screw, a bearing, a bearing housing, a socket, a guide rail, and a slider. The Hooke hinge includes a T-shaft, a bearing, a nut, and a retaining ring. The linear module slide, fixed to the frame support, is connected to one end of the support body via a revolute joint. The other end is connected to the moving platform via a Hooke joint. The second and fourth drive branches include a Hooke joint, a servo electric cylinder, and a rotary joint. The Hooke joint includes a T-shaft, a bearing, a nut, and a snap ring. The upper end of the servo electric cylinder is connected to the Hooke joint fixed on the frame, and the other end is connected to the moving platform via a rotary joint. The intermediate constraint branch includes two rotary joints and a sliding device. One end of the sliding device is connected to the frame support via a rotary joint, and the other end is connected to the moving platform via a rotary joint. The rotation axes of the two rotary joints connected by the sliding device are perpendicular. The moving platform includes an engraving head and a servo motor. The working platform includes a two-degree-of-freedom moving slide rail, an engraving table, and a vise.

[0007] The aforementioned parallel carving robot based on visual perception is characterized in that: the second rotation axis of the Hooke joint of the first driving branch and the third driving branch is parallel to the x-axis of the fixed coordinate system o-xyz and parallel to the rotation axis of the revolute joint; the second driving branch and the fourth driving branch are characterized in that the second rotation axis of the Hooke joint is parallel to the y-axis of the fixed coordinate system o-xyz and parallel to the rotation axis of the revolute joint.

[0008] The aforementioned parallel carving robot based on visual perception is characterized in that: the intermediate constraint branch is located in the middle of the moving platform, the rotation axis of the rotary joint connected to the frame base is parallel to the rotation axis of the rotary joint of the first driving branch and the third driving branch, and the rotation axis of the rotary joint connected to the moving platform is parallel to the rotation axis of the rotary joint of the second driving branch and the fourth driving branch.

[0009] A control method for a parallel carving robot based on vision perception, characterized in that: applied to the above-mentioned parallel carving robot, the control method includes the following steps:

[0010] (1) Establishing kinematic equations based on the closed vector method of geometric loops:

[0011]

[0012] In the formula, d i b represents the linear displacement of the driving branch. i R is the position vector of the hinge point of the kinematic pair in the fixed coordinate system, and R represents the rotation matrix of the moving coordinate system relative to the fixed coordinate system. α and β represent the Euler angles of the transformation of the moving coordinate system about the fixed coordinate system. The inverse kinematics equations of the parallel carving robot are expressed as:

[0013]

[0014] The above equation establishes a mapping equation characterizing the pose parameters of the drive joint and the moving platform in the operational space, where z represents the displacement of the origin of the moving platform coordinate system relative to the fixed coordinate system, and satisfies the constraint equations:

[0015]

[0016] In the formula, y represents the position information of the origin of the moving platform coordinate system in the y-direction;

[0017] (2) By differentiating the kinematic equations with respect to time, we can obtain the velocity characterizing the driving joint. Independent pose parameters of the moving platform Velocity mapping equation:

[0018]

[0019] In the formula, J0 is the speed Jacobian matrix of the parallel carving robot;

[0020] (3) Differentiate the above equation with respect to time to establish the acceleration of the driving joint. Independent pose parameters of the moving platform The acceleration mapping equation is:

[0021]

[0022] (4) Based on the principle of virtual work and d'Alembert's principle, a dynamic model of the parallel carving robot is constructed to obtain the mapping representation of the dynamic equations in the operating space:

[0023]

[0024] In the formula, For external forces on the operating space dynamic platform, Let be the positive definite inertia matrix of the system. The system's Coriolis force and centrifugal force matrices are given. The generalized force matrix of the system;

[0025] By utilizing the duality between the velocity Jacobian matrix and the force Jacobian matrix, the dynamic equations for driving the joint space are established:

[0026]

[0027] In the formula,

[0028] (5) The position and orientation of the carving robot's moving platform are obtained based on the visual perception sensor, and the position and orientation tracking error in the operating space is set as follows: The speed tracking error is ,and

[0029]

[0030] In the formula, and The expected state and speed of the operating space dynamic platform parameters, and For actual state and speed;

[0031] Define the degree of freedom synchronization error as:

[0032]

[0033] In the formula, H(t) is the mapping matrix characterizing the tracking error and synchronization error, and N is the number of degrees of freedom of the mechanism.

[0034] Taking into account both trajectory tracking error and degree-of-freedom synchronization error, the cross-coupling error and velocity are defined as follows:

[0035]

[0036] In the formula, P and Q are positive definite matrices;

[0037] Set the reference speed of the moving platform and reference acceleration Defined as:

[0038]

[0039] Define the sliding surface function and its derivative as follows:

[0040]

[0041] The sliding mode controller design consists of three parts, the first part being the dynamic compensation term:

[0042]

[0043] Y represents a known n×r regression matrix. Represents an r×1 vector of unknown parameters;

[0044] The second part is the mixed error compensation term:

[0045]

[0046] The third part is the robustness aspect:

[0047]

[0048] In the formula Indicates robust control terms, There are three behavioral patterns;

[0049] Ultimately, based on the requirements for system stability and precision control, a sliding mode control method under upper bound constraints was adopted, and the mathematical model of the sliding mode controller was designed as follows:

[0050]

[0051] A control method for a parallel carving robot based on visual perception is characterized in that: the first driving branch, the second driving branch and the third driving branch use position as the input to the driving joint, and the fourth driving branch uses force as the input to the joint.

[0052] Compared with the prior art, the present invention has the following advantages: (1) The combination of redundant drive and force-position hybrid control effectively reduces the chatter phenomenon in the processing process and improves the processing accuracy and stability. The redundant drive also optimizes the internal force distribution of the drive chain, enhancing the flexibility and adaptability of the system; (2) The structural design is simple. The load and weight distribution are optimized by fewer degrees of freedom and good symmetry, improving the load-bearing capacity, response speed and accuracy; (3) Based on the data fusion of visual perception sensors, the position and posture of the moving platform are obtained in real time. The sliding mode controller is used to improve the working accuracy of the end effector, enhancing the robustness and intelligence of the system; (4) It is suitable for high-precision engraving, personalized customization, small batch production and industrial automation, and has a wide range of application prospects. Attached Figure Description

[0053] Figure 1 This is a schematic diagram of the overall structure of a parallel carving robot based on visual perception according to the present invention.

[0054] Figure 2 This is a schematic diagram of the first and third drive branches of a parallel carving robot based on visual perception according to the present invention.

[0055] Figure 3 This is a schematic diagram of the second and fourth drive branches of a parallel carving robot based on visual perception according to the present invention.

[0056] Figure 4 This is a schematic diagram of the intermediate constraint branch structure of a parallel carving robot based on visual perception according to the present invention.

[0057] Figure 5 This is a schematic diagram of the dynamic platform structure of a parallel carving robot based on visual perception according to the present invention.

[0058] Figure 6 This is a schematic diagram of the working platform and moving slide rail structure of a parallel carving robot based on vision perception according to the present invention.

[0059] Figure 7 This is a flowchart of a parallel carving robot control method based on visual perception according to the present invention.

[0060] in:

[0061] Figure 1 In the middle: 1. First drive branch; 2. Second drive branch; 3. Third drive branch; 4. Fourth drive branch; 5. Intermediate constraint branch; 6. Moving platform; 7. Working platform; 8. Moving slide rail; 9. Frame support;

[0062] Figure 2 In the middle: 10. Servo motor; 11. Motor support; 12. Revolute joint; 13. Support body; 14. Hooke's joint; 15. Bearing support; 16. Ball screw; 17. Slider; 18. Coupling; 19. Slide rail;

[0063] Figure 3 Chinese: 20. Electric cylinder; 21. Electric actuator; 22. Rotary joint; 23. Servo motor; 24. Hooke joint;

[0064] Figure 4 In Chinese: 25. Telescopic rod; 26. Revolute joint; 27. Passive prismatic joint; 28. Revolute joint;

[0065] Figure 5 51. Engraving head support; 52. Engraving head; 53. Servo motor;

[0066] Figure 6 61. Vise; 62. Engraving platform; 63. Servo motor; 64. Moving slide rail. Detailed Implementation

[0067] To further understand the visual perception-based parallel carving robot and its control method provided by the present invention, the present invention will be specifically described below with reference to the accompanying drawings and detailed embodiments. The present invention is not limited to the embodiments.

[0068] Figure 1 This is a schematic diagram of the overall structure of a parallel carving robot based on visual perception according to the present invention, including a frame support 9, a movable slide rail 8, a working platform 7, a moving platform 6 for mounting the carving head, and a first drive branch 1, a second drive branch 2, a third drive branch 3, and a fourth drive branch 4 connecting the moving and fixed platforms; the key feature is that the connection points of the four drive branches and the fixed platform 7 are evenly distributed at the vertices of a regular quadrilateral, and the hinge points of the kinematic pairs connecting the moving platform 6 for mounting the spindle head and the four drive branches are evenly distributed at the vertices of the regular quadrilateral.

[0069] Furthermore, Figure 2 This is a schematic diagram of the first and third drive branches of a parallel carving robot based on visual perception according to the present invention. The first drive branch 1 and the third drive branch 3 have the same structure, including a linear module slide, a rotary joint, and a Hooke joint. The linear module slide includes: a servo motor 10, a motor support 11, a rotary joint 12, a support body 13, a Hooke joint 14, a bearing support 15, a ball screw 16, a slider 17, a coupling 18, and a slide rail 19. The rotation axis of the rotary joint 12 connecting the drive branch to the support body 13 is parallel to the x-axis in the fixed coordinate system o-xyz and parallel to the second rotation axis of the Hooke joint 14. It is fixed to the moving platform 6 through a connecting flange.

[0070] Furthermore, Figure 3 This is a schematic diagram of the second and fourth drive branches of a parallel carving robot based on vision perception according to the present invention. The second drive branch 2 and the fourth drive branch 4 have the same structure, including a Hooke joint, a servo electric cylinder and a rotary joint; the servo electric cylinder includes a servo motor 23, an electric cylinder 20 and an electric push rod 21; the rotary joint 22 of the drive branch is parallel to the y-axis of the fixed coordinate system o-xyz and parallel to the second rotation axis of the Hooke joint 24, and the rotary joint 22 is connected to the moving platform 6 equipped with the spindle head.

[0071] Furthermore, Figure 4This is a schematic diagram of the intermediate constraint branch structure of a parallel carving robot based on visual perception according to the present invention. The intermediate constraint branch 5 includes a revolute joint connected to the top frame, a sliding device, and a revolute joint connected to the moving platform. The upper end of the intermediate constraint branch 5 is connected to the frame support through a revolute joint 28. The rotation axis of the revolute joint 28 is parallel to the rotation axis of the revolute joints of the first and third driving branches, and parallel to the x-axis in the fixed coordinate system o-xyz. The lower end of the intermediate constraint branch 5 is located in the middle of the moving platform and connected to the moving platform through a revolute joint 26. The rotation axis of the revolute joint 26 is parallel to the rotation axis of the revolute joints of the second and fourth driving branches, and parallel to the y-axis in the fixed coordinate system o-xyz.

[0072] Furthermore, the first rotation axis of the Hooke's joint 14 in the first drive branch 1 is collinear with the first rotation axis of the Hooke's joint 14 in the third drive branch; the first rotation axis of the Hooke's joint 24 in the second drive branch 2 is collinear with the first rotation axis of the Hooke's joint 24 in the fourth drive branch 4; the revolute joint 12 in the first drive branch 1 is parallel to the revolute joint 12 in the third drive branch 3; and the revolute joint 22 in the second drive branch 2 is parallel to the revolute joint 22 in the fourth drive branch 4. One end of the first drive branch 1 and the third drive branch 3 are connected to the linear module slide table via the revolute joint 12 and vertically fixed to the frame support 9; the other end is connected to the moving platform 6 via the Hooke's joint 14. One end of the second drive branch 2 and the fourth drive branch 4 are connected to the frame support 9 via the Hooke's joint 24; and the other end is connected to the moving platform via the revolute joint 22. The four drive branches are symmetrically distributed at the four vertices of the moving platform.

[0073] Furthermore, Figures 5-6 This is a schematic diagram of the moving platform structure of a parallel carving robot based on vision perception according to the present invention. The moving platform includes a carving head support 51, a carving head 52, and a servo motor 53. The working platform and the moving slide rail include a vise 61, a carving platform 62, a servo motor 63, and a moving slide rail 64.

[0074] Figure 7 This is a flowchart of a vision-based parallel carving robot control method according to the present invention. Its characteristic is that, applied to the aforementioned parallel carving robot, the control method includes the following steps:

[0075] (1) Establishing kinematic equations based on the closed vector method of geometric loops:

[0076]

[0077] In the formula, d i b represents the linear displacement of the driving branch. i R is the position vector of the hinge point of the kinematic pair in the fixed coordinate system, and R represents the rotation matrix of the moving coordinate system relative to the fixed coordinate system. α and β represent the Euler angles of the transformation of the moving coordinate system about the fixed coordinate system. The inverse kinematics equations of the parallel carving robot are expressed as:

[0078]

[0079] The above equation establishes a mapping equation characterizing the pose parameters of the drive joint and the moving platform in the operational space, where z represents the displacement of the origin of the moving platform coordinate system relative to the fixed coordinate system, and satisfies the constraint equations:

[0080]

[0081] In the formula, y represents the position information of the origin of the moving platform coordinate system in the y-direction;

[0082] (2) By differentiating the kinematic equations with respect to time, we can obtain the velocity characterizing the driving joint. Independent pose parameters of the moving platform Velocity mapping equation:

[0083]

[0084] In the formula, J0 is the speed Jacobian matrix of the parallel carving robot;

[0085] (3) Differentiate the above equation with respect to time to establish the acceleration of the driving joint. Independent pose parameters of the moving platform The acceleration mapping equation is:

[0086]

[0087] (4) Based on the principle of virtual work and d'Alembert's principle, a dynamic model of the parallel carving robot is constructed to obtain the mapping representation of the dynamic equations in the operating space:

[0088]

[0089] In the formula, For external forces on the operating space dynamic platform, Let be the positive definite inertia matrix of the system. The system's Coriolis force and centrifugal force matrices are given. The generalized force matrix of the system;

[0090] By utilizing the duality between the velocity Jacobian matrix and the force Jacobian matrix, the dynamic equations for driving the joint space are established:

[0091]

[0092] In the formula,

[0093] (5) The position and orientation of the carving robot's moving platform are obtained based on the visual perception sensor, and the position and orientation tracking error in the operating space is set as follows: The speed tracking error is ,and

[0094]

[0095] In the formula, and The expected state and speed of the operating space dynamic platform parameters, and For actual state and speed;

[0096] Define the degree of freedom synchronization error as:

[0097]

[0098] In the formula, H(t) is the mapping matrix characterizing the tracking error and synchronization error, and N is the number of degrees of freedom of the mechanism.

[0099] Taking into account both trajectory tracking error and degree-of-freedom synchronization error, the cross-coupling error and velocity are defined as follows:

[0100]

[0101] In the formula, P and Q are positive definite matrices;

[0102] Set the reference speed of the moving platform and reference acceleration Defined as:

[0103]

[0104] Define the sliding surface function and its derivative as follows:

[0105]

[0106] The sliding mode controller design consists of three parts, the first part being the dynamic compensation term:

[0107]

[0108] Y represents a known n×r regression matrix. Represents an r×1 vector of unknown parameters;

[0109] The second part is the mixed error compensation term:

[0110]

[0111] The third part consists of the robustness terms that ensure the control system can still operate stably under the uncertainty of unknown parameters and external disturbances:

[0112]

[0113] In the formula Indicates robust control terms, There are three behavioral patterns;

[0114] Ultimately, based on the requirements for system stability and precision control, a sliding mode control method under upper bound constraints was adopted, and the mathematical model of the sliding mode controller was designed as follows:

[0115]

[0116] Furthermore, according to claim 4, the control method for a parallel carving robot based on visual perception is characterized in that: the first driving branch, the second driving branch and the third driving branch use position as the input to the driving joint, and the fourth driving branch uses force as the input to the joint.

[0117] The embodiments of the parallel carving robot based on vision perception and its control method of the present invention are not intended to limit the present invention. Based on the content disclosed in the present invention, those skilled in the art can also implement it in other specific ways without departing from the present invention, and all of them fall within the protection scope of the present invention.

Claims

1. A vision-based parallel carving robot, comprising a frame support, a parallel mechanism, and a working platform, characterized in that: An industrial camera is mounted on the frame support. The parallel mechanism includes four drive branches, an intermediate constraint branch, and a moving platform. The first and third drive branches include a linear module slide, a revolute joint, a support body, and a Hooke hinge. The linear module slide includes a servo motor, a motor bracket, a coupling, a ball screw, a bearing, a bearing housing, a nut, a guide rail, and a slider. The Hooke hinge includes a T-shaft, a bearing, a nut, and a retaining ring. The linear module slide, fixed to the frame support, is connected to one end of the support body via a revolute joint, and the other end of the support body is connected to the moving platform via the Hooke hinge. The second and fourth drive branches include a Hooke hinge, a servo electric cylinder, and a revolute joint. The Hooke hinge includes a T-shaft, a bearing, a nut, and a retaining ring. The upper end of the servo electric cylinder is connected to the Hooke hinge fixed to the frame, and the other end is connected to the moving platform via a revolute joint. The intermediate constraint branch includes two revolute joints and a sliding device. One end of the device is connected to the frame support via a revolute joint, and the other end is connected to the moving platform via a revolute joint. The rotation axes of the two revolute joints connected by the sliding device are perpendicular. The moving platform includes an engraving head and a servo motor. The working platform includes a two-degree-of-freedom sliding rail, an engraving table, and a vise. The second rotation axis of the Hooke joint of the first and third driving branches is parallel to the x-axis of the fixed coordinate system o-xyz and parallel to the rotation axis of the revolute joint in its driving branch. The second rotation axis of the Hooke joint of the second and fourth driving branches is parallel to the y-axis of the fixed coordinate system o-xyz and parallel to the rotation axis of the revolute joint in its driving branch. The intermediate constraint branch is located in the middle of the moving platform. The rotation axis of the revolute joint connected to the frame support is parallel to the rotation axes of the revolute joints of the first and third driving branches. The rotation axis of the revolute joint connected to the moving platform is parallel to the rotation axes of the revolute joints of the second and fourth driving branches.

2. A control method for a parallel carving robot based on vision perception, characterized in that: When the parallel carving robot of claim 1 is referenced, its control method includes the following steps: (1) Establishing kinematic equations based on the closed vector method of geometric loops: In the formula, d i b represents the linear displacement of the driving branch. i R is the position vector of the hinge point of the kinematic pair in the fixed coordinate system, and R represents the rotation matrix of the moving coordinate system relative to the fixed coordinate system. α and β represent the Euler angles of the transformation of the moving coordinate system about the fixed coordinate system. The inverse kinematics equations of the parallel carving robot are expressed as: The above equation establishes a mapping equation characterizing the pose parameters of the drive joint and the moving platform in the operational space, where z represents the displacement of the origin of the moving platform coordinate system relative to the fixed coordinate system, and satisfies the constraint equations: In the formula, y represents the position information of the origin of the moving platform coordinate system in the y-direction; (2) By differentiating the kinematic equations with respect to time, we can obtain the velocity characterizing the driving joint. Independent pose parameters of the moving platform Velocity mapping equation: In the formula, J0 is the speed Jacobian matrix of the parallel carving robot; (3) Differentiate the above equation with respect to time to establish the acceleration of the driving joint. Independent pose parameters of the moving platform The acceleration mapping equation is: (4) Based on the principle of virtual work and d'Alembert's principle, a dynamic model of the parallel carving robot is constructed to obtain the mapping representation of the dynamic equations in the operating space: In the formula, For external forces on the operating space dynamic platform, Let be the positive definite inertia matrix of the system. The system's Coriolis force and centrifugal force matrices are given. The generalized force matrix of the system; By utilizing the duality between the velocity Jacobian matrix and the force Jacobian matrix, the dynamic equations for driving the joint space are established: In the formula, (5) The position and orientation of the carving robot's moving platform are obtained based on the visual perception sensor, and the position and orientation tracking error in the operating space is set as follows: The speed tracking error is ,and In the formula, and The expected state and speed of the operating space dynamic platform parameters, and For actual state and speed; Define the degree of freedom synchronization error as: In the formula, H(t) is the mapping matrix characterizing the tracking error and synchronization error, and N is the number of degrees of freedom of the mechanism. Taking into account both trajectory tracking error and degree-of-freedom synchronization error, the cross-coupling error and velocity are defined as follows: In the formula, P and Q are positive definite matrices; Set the reference speed of the moving platform and reference acceleration Defined as: Define the sliding surface function and its derivative as follows: The sliding mode controller design consists of three parts, the first part being the dynamic compensation term: Y represents a known n×r regression matrix. Represents an r×1 vector of unknown parameters; The second part is the mixed error compensation term: The third part is the robustness aspect: In the formula Indicates robust control terms, There are three behavioral patterns; Ultimately, based on the requirements for system stability and precision control, a sliding mode control method under upper bound constraints was adopted, and the mathematical model of the sliding mode controller was designed as follows: 。 3. The control method for a parallel carving robot based on vision perception according to claim 2, characterized in that: The first, second, and third drive branches use position as the input to drive the joint, while the fourth drive branch uses force as the input to the joint.

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