Multi-track wafer handling robot and control method

Abstract

The present application relates to the technical field of wafers, in particular to a multi-track wafer carrying manipulator and control method, which adopts a mechanical arm assembly and an end effector to execute actions, wherein the mechanical arm assembly comprises three execution arms connected in turn; the end effector is installed at the end position of the execution arm farthest from the base, and the method is as follows: S1: setting a safety area so that the multiple execution arms are always in the safety area during movement; S2: iteratively setting the coordinates of each point from the boundary to the center in the safety area, and generating a safety link; S3: in a safety link, the end effector always faces the station position, and the center of the end effector moves along the safety link, and the angles a, b, c between the adjacent execution arms of each point and the angle d between the execution arm and the end effector are calculated; S4: traversing optimization is performed on the distance C in step S3, and the optimal C value is found; S5: the optimal time is obtained according to the optimal C value.

Description

Technical Field

[0001] This invention relates to the field of wafer handling technology, and in particular to a multi-track wafer handling robot and its control method. Background Technology

[0002] In the semiconductor manufacturing industry, wafer handling is a crucial step, permeating multiple wafer fabrication processes such as photolithography, etching, and deposition. As the fundamental material for semiconductor chip manufacturing, wafers possess extremely high value and precision; their surface flatness, cleanliness, and other parameters have a decisive impact on chip performance and quality. Therefore, during wafer handling, it is essential to ensure extremely high precision and stability, avoiding any factors that could damage the wafer, such as collisions, vibrations, and contamination.

[0003] In semiconductor manufacturing workshops, production equipment is laid out compactly, leaving very limited space for wafer handling robots to operate. Traditional three-way robots have significant limitations in handling wafers within this confined space. When wafer retrieval needs to be performed in a narrow space, existing robotic arms have the following drawbacks:

[0004] First, a dual-arm robotic arm is used. In order to meet the requirements of long-distance wafer picking and placing, each arm is set to be relatively long (i.e., the center distance is large). However, if the arm is too long, it will cause interference with the surrounding compartments when the robotic arm adjusts its posture and position. If the arm is shortened to avoid collision with the interference position, the purpose of long-distance wafer picking and placing cannot be met.

[0005] Secondly, with the use of a three-arm robotic arm, the weight at the front end accumulates as the number of arms increases, leading to excessive load. During handling, this excessive weight can cause the robotic arm's front end to sag. This sagging severely affects the robotic arm's positioning accuracy, preventing the wafer from being accurately placed at the target location and thus impacting subsequent processing steps. Summary of the Invention

[0006] The purpose of this invention is to provide a multi-track wafer handling robot and its control method to solve the problem of inefficient wafer handling in narrow spaces in the prior art.

[0007] The technical solution of the present invention is: a control method for a multi-track wafer handling robot, which uses a robot arm assembly and an end effector to perform actions. The robot arm assembly includes three sequentially rotatably connected execution arms, which are, from the base to the end effector, a forearm, a middle arm, and a forearm. The end effector is installed at the end of the execution arm furthest from the base and is configured to rotate around the connection point.

[0008] The method is as follows:

[0009] S1: Safety Zone Setting: Multiple actuators remain within the safety zone during movement;

[0010] S2: Trajectory planning: Iterate the coordinates of each point from the boundary to the center within the safe area and generate a safe link;

[0011] S3: End effector path planning: In a safe link, the end effector always faces the site location and moves the center of the end effector along the safe link. Calculate the angles a, b, c between adjacent actuator arms and the angle d between the forearm and the end effector at each point;

[0012] S4: Calculation of the optimal C value: Iterate and optimize the distance C in step S3, and find the optimal C value;

[0013] S5: Obtain the optimal time based on the optimal C value: When the maximum speed, maximum acceleration, and maximum acceleration of the end effector are greater than the threshold, the total time increases by 50%; when the maximum speed, maximum acceleration, and maximum acceleration of the end effector are less than the threshold, the total time decreases by 50%.

[0014] Preferably, step S2 includes the following sub-steps:

[0015] S2.1: Obstacle Boundary Iteration: Set three boundary obstacle endpoints as P1, Q1, and R1, and iterate from P1, Q1, and R1 towards the origin O at intervals of 5mm.

[0016] S2.2: SBPLX Optimization:

[0017] set up The SBPLX numerical optimization algorithm was used to obtain P1...P n Q1...Q n R1...R n Location link;

[0018] S2.2.1: Calculate the projection points M of the next point P(i+1) and the three obstacles:

[0019] ;

[0020] A1, A2, A3, A4: The coordinates of the four corners of the first obstacle;

[0021] B1, B2, B3, B4: The coordinates of the four corners of the second obstacle;

[0022] C1, C2, C3, C4: The coordinates of the four corners of the third obstacle;

[0023] : Coefficient, with a value range of [0,1];

[0024] S2.2.2: Using the SBPLX numerical optimization algorithm, optimize the angle of the next point relative to the previous point to maximize the minimum distance from the above 5 points to P(i+1), thus obtaining P1...P n Q1...Q n R1...R n Location link;

[0025] S2.3: Using a quadratic polynomial, perform local curve fitting on the above-mentioned location links, project the points onto the curve, and obtain a smooth safe link curve.

[0026] Preferably, step S3 includes the following steps:

[0027] S3.1: Among the three links above, select P. i P j Q i Q j R i R j The link containing the nearest point to the origin O;

[0028] S3.2: First, teach or design the coordinates (x, y) and posture Y of the forearm end, and when the distance between the forearm end and the forearm end is C, the calculation formulas for each angle are as follows:

[0029] ;

[0030] ;

[0031] ;

[0032] ;

[0033] a: The angle between the forearm and the x-axis;

[0034] b: The angle between the forearm and the midarm;

[0035] c: The angle between the midarm and forearm;

[0036] d: Angle between the forearm and the end effector;

[0037] W: The distance between the coordinates (x, y) of the forearm end and the origin O;

[0038] B: Length of forearm, midarm, and forearm.

[0039] Preferably, step S4 includes the following steps:

[0040] S4.1: Set the initial value C=B, and import the value of C into the second derivatives corresponding to a, b, and c, so that the ratio of the corresponding second derivatives to a constant is equal, and calculate the root mean square error of each ratio;

[0041] S4.2: Use the CGAL geometric algorithm to determine whether there is a collision with an obstacle. If there is a collision, return the maximum value; if there is no collision, return the mean square error.

[0042] S4.3: Utilize the COBYLA numerical optimization algorithm to automatically find the optimal C value.

[0043] A multi-track wafer handling robot includes:

[0044] A base and a Z-axis mounting component penetrating the base, wherein the Z-axis mounting component has a mounting plane perpendicular to the Z-axis;

[0045] The robotic arm assembly includes three sequentially rotatably connected actuators, with their front ends mounted and fixed on the mounting plane, and having an applied locking force;

[0046] At least one end effector is mounted at the end of the actuator arm furthest from the base and configured to rotate about the connection point;

[0047] A collar structure is provided between the base and the Z-axis mounting component to limit the droop of the end of the robotic arm assembly.

[0048] Preferably, the actuator arm, from the base to the end effector, consists of a forearm, a middle arm, and a forearm; the forearm, middle arm, forearm, and end effector each have an independent drive mechanism.

[0049] Preferably, the forearm is equipped with a first drive mechanism, and the output end of the first drive mechanism is fixedly connected to the Z-axis mounting component;

[0050] The middle arm is equipped with a second drive mechanism, which is distributed within the Z-axis mounting component and the forearm.

[0051] The forearm is equipped with a third drive mechanism, which is distributed within the middle arm;

[0052] The end effector is equipped with a fourth drive mechanism and is distributed within the forearm.

[0053] Preferably, the first drive mechanism, the second drive mechanism, the third drive mechanism and the fourth drive mechanism all adopt a combination of servo motor and conveyor belt;

[0054] The servo motor of the first drive mechanism is configured outside the actuator arm and the Z-axis mounting component;

[0055] The servo motor of the second drive mechanism is configured within the Z-axis mounting component;

[0056] The servo motors in the third and fourth drive mechanisms are located on the side of the middle arm and forearm, respectively, near the front end.

[0057] Preferably, two sets of the end effector are provided, which in turn correspond to two sets of the fourth drive mechanism;

[0058] The two sets of servo motors of the fourth drive mechanism are distributed along the width direction of the forearm and connected to the integrated reducer via a conveyor belt. The two sets of reducers are distributed along the length direction of the forearm, and the output end of the reducer is also connected to the input end of the end effector via a conveyor belt.

[0059] Preferably, a plurality of locking members are provided between the forearm and the Z-axis mounting member. The plurality of locking members are arranged in a ring and a mechanical preload is applied to eliminate or reduce the assembly gap at the connection between the forearm and the Z-axis mounting member, so as to suppress the tilting of the forearm caused by the force generated by the weight of the forearm and its end effector.

[0060] Compared with the prior art, the advantages of the present invention are:

[0061] (1) By calculating the minimum distance from 5 points to P(i+1) to the maximum, and using a quadratic polynomial, a safety link curve is fitted, and the angle values ​​of a, b, c, and d are calculated, so that the robot arm does not collide with the three obstacle avoidance zones during the movement.

[0062] (2) Construct constraints on the second derivatives of C with respect to four angles a, b, c, and d, thereby obtaining the optimal value of C, which satisfies the condition of minimizing the root mean square error without colliding with obstacles, making the motion trajectory more stable, making it easier to accurately control the position of the end effector, and reducing its vibration.

[0063] (3) Based on the design of the three-way robot, the end effector can pick up and put away wafers at a distance. However, the longer the end effector extends, the greater the droop of its end. By adding a collar, a good support can be provided, improving mechanical stability and effectively limiting the droop of the end of the robot arm assembly. Furthermore, by applying a locking force to the front end of the robot arm assembly, the deformation of the connection caused by the torque can be overcome, and the collar can also be effectively protected.

[0064] (4) Abandoning the traditional three-arm robot design where the length of the robotic arm decreases step by step from the base to the gripping end, the robot adopts three robotic arms of equal length and independent drive systems. Each robotic arm is equipped with an independent drive device, which gives each execution arm the ability to independently adjust motion parameters. This greatly improves the robot's motion flexibility, makes the trajectory more varied, and can adapt to complex and varied wafer gripping scenarios. The equal-length execution arms provide a regular and symmetrical basis for motion trajectory planning, which is convenient for establishing mathematical models, accurately calculating position and posture, planning smooth and efficient motion trajectories, achieving real-time precise control, reducing interference and collisions, avoiding the risk of long arm collisions through compact design, achieving complete decoupling of motion, and improving the operational flexibility and multi-arm collaborative stability in a limited space.

[0065] (5) Each drive mechanism is reasonably arranged, and the servo motors are all arranged at the front end of the corresponding execution arm to overcome the sagging problem of the end effector to the greatest extent. In the fourth drive mechanism inside the forearm, two sets of servo motors are distributed along the width direction of the forearm and an integrated reducer is used to minimize the space occupancy of the fourth drive mechanism, thereby reducing the center distance of the forearm. Since each execution arm is of equal length, it can be easily moved in a narrow space, avoiding interference with external equipment.

[0066] (6) The drive mechanism adopts belt drive, which ensures smooth power transmission. When encountering load changes or short-term impacts, the elastic deformation of the belt can absorb some energy, reduce impact, ensure the rotational stability of the end effector, and avoid vibration during wafer handling. At the same time, the long span of the belt is changed to a short span through the intermediate pulley, which reduces the elastic elongation of the belt under force and suppresses the end vibration caused by belt deformation. Furthermore, the transmission ratio can be easily adjusted by changing the diameter of the intermediate pulley, and the rotational speed and torque of the end effector can be flexibly adjusted according to different wafer handling requirements to better adapt to various working conditions. Attached Figure Description

[0067] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0068] Figure 1 This is a flowchart of a control method for a multi-track wafer handling robot according to the present invention;

[0069] Figure 2 This is a schematic diagram showing the state of the robotic arm in its initial position according to the present invention;

[0070] Figure 3 This is a schematic diagram showing the state of the robotic arm in the ready position according to the present invention;

[0071] Figure 4 This is a schematic diagram showing the state of the robotic arm in the grasping position according to the present invention;

[0072] Figure 5This is a graph showing the acceleration of the robotic arm described in this invention within 1 second versus time.

[0073] Figure 6 This is a schematic diagram of the structure of a multi-track wafer handling robot according to the present invention;

[0074] Figure 7 This is a schematic diagram of the internal structure of the forearm described in this invention;

[0075] Figure 8 This is a top view of a multi-track wafer handling robot according to the present invention;

[0076] Figure 9 This is a partial cross-sectional view of the base and the first driving mechanism described in this invention;

[0077] Figure 10 This is a side view of a multi-track wafer handling robot according to the present invention.

[0078] The components include: 1. Base; 2. Z-axis mounting component; 21. Mounting plane; 3. Robotic arm assembly; 31. Execution arm; 311. Forearm; 312. Middle arm; 313. Forearm; 4. End effector; 5. Collar structure; 6. Drive mechanism; 61. First drive mechanism; 62. Second drive mechanism; 63. Third drive mechanism; 64. Fourth drive mechanism; 7. Reducer; 8. Tensioner wheel; 9. Locking component; 10. Lifting module. Detailed Implementation

[0079] The present invention will be further described in detail below with reference to specific embodiments:

[0080] like Figure 2-4 As shown, the robotic arm has three positions during its movement: an initial position, a ready position, and a gripping position. When the robotic arm transitions from the initial position to the ready position, the end effector aligns with the wafer storage location. During wafer placement and removal, multiple wafer storage areas are provided around the robotic arm, collectively forming its movement area. In this embodiment, a first obstacle, a second obstacle, and a third obstacle are provided, which together form a T-shaped area for the robotic arm's movement. To prevent collisions between the robotic arm and the obstacle avoidance area and to ensure stability during movement, the following steps are employed.

[0081] like Figure 1 As shown, step S1: Setting the safe zone:

[0082] By setting a rectangular safety zone, the robot arm is ensured to remain within this zone throughout the entire process from the initial position to the ready position, avoiding collisions with obstacles. Even in extreme positions, the actuator arm and end effector remain within the safety zone and will not collide with obstacles.

[0083] Step S2: Trajectory Planning

[0084] Obstacle boundary iteration: Iterating from the three obstacle endpoints P1, Q1, R1 towards the origin O with a step size of 5mm, a discrete point set is generated. Safe path points are selected by calculating the minimum distance M of the projection of each point onto the sides of the three obstacles; subsequently, the SBPLX numerical optimization algorithm is used to optimize and obtain P1...P n Q1...Q n R1...R n Three links at different locations are used, and a quadratic polynomial is used to locally fit the discrete points to generate a smooth, secure link curve.

[0085] During the SBPLX optimization process, according to Calculate the coordinates of the next point, call the SBPLX numerical optimization algorithm to find the angle of the next point relative to the previous point, i.e., P(i+1) relative to P(i), and obtain the minimum distance M between P(i+1) and the three obstacles. The formula for calculating M is as follows:

[0086] ;

[0087] A1, A2, A3, A4: The coordinates of the four corners of the first obstacle;

[0088] B1, B2, B3, B4: The coordinates of the four corners of the second obstacle;

[0089] C1, C2, C3, C4: The coordinates of the four corners of the third obstacle;

[0090] : Coefficients, with values ​​ranging from [0,1]; P1...P is obtained by calling the SBPLX numerical optimization algorithm. n Q1...Q n R1...R n Based on the three location links above, calculate the link with the smallest distance from the origin O to the nearest point among the three location links, and select this location link as the trajectory path.

[0091] Step S3: End effector path planning

[0092] like Figure 5 As shown, P1...P n Taking the position link as an example, the center of the end effector is from the origin O to P. i During the movement, the center of the end effector moves along the curve of the safety link. Within 1 second, based on the coordinates (x, y) of the forearm end effector and the distance C (the straight-line distance between the forearm end effector and the forearm end effector), the angles of each joint are calculated using the following formula:

[0093] ;

[0094] ;

[0095] ;

[0096] ;

[0097] a: The angle between the forearm and the x-axis;

[0098] b: The angle between the forearm and the midarm;

[0099] c: The angle between the midarm and forearm;

[0100] d: Angle between the forearm and the end effector;

[0101] W: The distance between the coordinates (x, y) of the forearm end and the origin;

[0102] B: Length of forearm, midarm, and forearm;

[0103] Y: The angle between the end effector and the x-axis.

[0104] The mathematical relationship between a, b, c, d and C is obtained through the above calculation formula. By continuously optimizing the value of C, each value of C corresponds to different values ​​of a, b, c, d, thus enabling the determination of the position of each actuator arm and end effector.

[0105] Step S4: Iterate through and optimize C in step S3, and find the optimal value of C;

[0106] Taking the second derivative with respect to angles a, b, and c, we obtain the following second derivative with respect to C;

[0107] ;

[0108] ;

[0109] ;

[0110] Construct the following relation as the optimal solution for C.

[0111] ;in, All values ​​are constants and are calculated based on the design specifications using the rated torque of the drive mechanism (i.e., motor) corresponding to each actuator arm. The second derivative of each angle is the angular acceleration. When all ratios are equal, the robot arm has the best stability during movement. Therefore, different constant values ​​are set to make the above formula true, thus achieving the optimal C value.

[0112] S4.1: Set the initial value C=B, and import the value of C into the second derivatives corresponding to a, b, and c, and calculate the corresponding second derivatives and... The mean square error of the ratio;

[0113] S4.2: Use a triangular facet data structure to represent the 3D contours of the forearm, mid-arm, forearm, end effector, and obstacles. Then use the CGAL algorithm to determine whether the triangular facet sets intersect and whether there is a collision with an obstacle. If there is a collision, return the maximum value; if there is no collision, return the mean square error.

[0114] S4.3: Utilize the COBYLA numerical optimization algorithm to automatically find the optimal C value.

[0115] S5: Obtain the optimal time based on the optimal C value: When the maximum speed, maximum acceleration, and maximum acceleration of the end effector are greater than the threshold, increase the total time required for each actuator arm and end effector to run to the corresponding position by 50%. When the maximum speed, maximum acceleration, and maximum acceleration of the end effector are less than the threshold, decrease the total time required for each actuator arm and end effector to run to the corresponding position by 50%, until the maximum speed, maximum acceleration, and maximum acceleration are all within the threshold range.

[0116] like Figures 6-10 As shown, a multi-track wafer handling robot includes a base 1, a Z-axis mounting component 2, a robotic arm assembly 3, an end effector 4, and a collar structure 5. The base 1 serves as the fundamental support component of the entire robot, securely mounted on a lifting module 10, and moves up or down with the lifting module 10 to adjust the overall height of the robot, adapting to wafer handling operations at different heights. The robotic arm assembly 3 is composed of multiple actuator arms 31 connected in sequence, each with a certain degree of rotational freedom. Through the relative rotational coordination between the actuator arms 31, the robot can flexibly extend and retract in multiple directions. An end effector 4, a wafer clamping device, is installed at the end of the actuator arm 31 furthest from the base 1, directly contacting the wafer and lifting it from its bottom.

[0117] Since the end effector 4 is installed at the end of the robotic arm assembly 3 and is far from the base 1, each end effector 4 needs to be equipped with a separate drive mechanism 6 to meet its complex action requirements such as grasping and rotation. However, this layout leads to a significant increase in the front-end load, making the end of the robotic arm a concentrated area of ​​inertial mass. When the robotic arm moves or frequently starts and stops, the excessive inertial force at the front end will cause elastic vibration. Especially in the process of handling ultra-thin and brittle materials such as wafers, it may cause wafer edge damage or surface particle contamination, which seriously affects the semiconductor manufacturing yield. Therefore, in this embodiment, the Z-axis mounting component 2 has a mounting plane 21 perpendicular to the Z-axis, and the front end of the robotic arm assembly 3 is fixed on the mounting plane 21. A space is provided between the robotic arm assembly 3 and the Z-axis mounting component 2. There are several locking components 9 arranged in a ring. By applying a mechanical preload, the robotic arm assembly 3 generates a downward force at its front end to eliminate or reduce the assembly gap at the connection between the robotic arm assembly 3 and the Z-axis mounting component 2. At the same time, a collar structure 5 is installed between the base 1 and the Z-axis mounting component 2 to effectively eliminate or significantly reduce the original assembly gap at the connection between the two. In actual operation, if there is an assembly gap between the robotic arm assembly 3 and the Z-axis mounting component 2, the robotic arm assembly 3 is prone to tilting, which affects the stability of the end effector. Therefore, by generating a downward force on the robotic arm assembly 3 and reducing the gap between the base 1 and the Z-axis mounting component 2, the droop of the end effector of the robotic arm assembly 3 is reduced.

[0118] like Figure 10As shown, traditional three-way robotic arms often adopt a structural design in which the length of the robotic arm decreases step by step from the base 1 to the end effector 4. Although this structure can expand the end-effector's operating range and increase stability to some extent, it has significant drawbacks in a limited space. The long robotic arm is prone to interference with surrounding equipment due to its large rotation radius, which leads to limited angle adjustment and reduced end-effector positioning accuracy. At the same time, the robotic arms are linked together through a rigid transmission mechanism, resulting in highly coupled motion. The inertial force generated when a single robotic arm moves will be transmitted to other robotic arms through the transmission chain, causing overall vibration and interfering with the stability of collaborative operation. Therefore, this application employs three equally long actuator arms 31, which are, in sequence from the base 1 to the end effector 4, a forearm 311, a middle arm 312, and a forearm 313. Through the relative rotational cooperation between the forearm 311, the middle arm 312, and the forearm 313, the manipulator can flexibly extend and retract in multiple directions. The forearm 311 is equipped with a first drive mechanism 61, and the output end of the first drive mechanism 61 is fixedly connected to the Z-axis mounting component 2. The middle arm 312 is equipped with a second drive mechanism 62, distributed within the Z-axis mounting component 2 and the forearm 311. The forearm 313 is equipped with a third drive mechanism 62. The drive mechanism 63 is located within the middle arm 312, and the end effector 4 is equipped with a fourth drive mechanism 64 located within the forearm 313. Each actuator arm 31 has the ability to independently adjust its motion parameters according to actual needs through its independent drive mechanism 6. When gripping wafers at different heights or angles, each actuator arm 31 can independently adjust its extension length or rotation angle through its own drive mechanism 6, greatly improving the flexibility of the robot's movement and enabling it to adapt to complex and varied wafer gripping scenarios. Furthermore, the equal-length actuator arms 31 provide a more regular and symmetrical basis for motion trajectory planning. When the robot performs spatial movements, the equal-length actuator arms 31 make it easier to establish mathematical models, accurately calculate the position and posture of each actuator arm 31 at different times, and thus plan a smoother and more efficient motion trajectory. According to the planned trajectory, the movement of each robotic arm 31 can be controlled in real time and with precision, reducing interference and collisions during the movement process. The compact design avoids the risk of collisions with long arms and achieves complete decoupling of movement, ensuring that each robotic arm can adjust its posture independently and precisely, significantly improving the operational flexibility and collaborative stability of multiple robotic arms in a limited space.

[0119] Specifically, there are two sets of end effectors 4, which in turn correspond to two sets of fourth drive mechanisms 64. The servo motors of the two sets of fourth drive mechanisms 64 are distributed along the width direction of the forearm 313 and connected to the integrated reducer 7 via a conveyor belt. The two sets of reducers 7 are distributed along the length direction of the forearm 313. The output end of the reducer 7 is also connected to the input end of the end effector 4 via a conveyor belt. By replacing the traditional reducer 7 with the integrated reducer 7, and by arranging the servo motors of the fourth drive mechanism 64 along the width direction, the overall length of the forearm 313 is reduced, the overall weight of the robotic arm assembly 3 is reduced, and the stability of the robotic arm assembly 3 is improved.

[0120] In addition, such as Figure 8 As shown, the drive end of the servo motor of the fourth drive mechanism 64, the output end of the reducer 7, and the input end of the end effector 4 form a multi-stage belt drive structure through a closed belt loop. When the fourth drive mechanism 64 is started, the drive end of the servo motor drives the reducer 7 to rotate through the friction of the belt. The reducer 7 then transmits power to the input shaft of the end effector 4 through another belt, realizing rotational drive. By splitting a single long-span belt into two short-span transmissions, namely the short span between the servo motor of the fourth drive mechanism 64 and the reducer 7, and the short span between the reducer 7 and the end effector 4, the elastic elongation of the belt under stress is significantly reduced, effectively suppressing the end vibration caused by belt deformation.

[0121] Furthermore, the first drive mechanism 61, the second drive mechanism 62, the third drive mechanism 63, and the fourth drive mechanism 64 all adopt a combination of servo motors and conveyor belts. During power transmission, when encountering load changes or brief impacts, the conveyor belt can undergo a certain degree of elastic deformation, absorbing some energy and reducing the impact on the fourth drive mechanism 64 and the end effector 4. This makes power transmission smoother, helps ensure the stability of the end effector 4 during rotation, and avoids wafer wobbling during wafer handling due to unstable power transmission, thus improving the quality and reliability of wafer handling. Compared with other transmission methods, such as gear transmission, which may require more space to arrange gear sets, belt transmission can achieve efficient power transmission in a limited space. This is beneficial for the miniaturization and integration design of robotic arms, adapting to working environments with high equipment space requirements, such as semiconductor production lines. By changing the diameter of the intermediate pulley, the transmission ratio between the power output end and the input shaft of the end effector 4 can be easily adjusted.

[0122] In practical applications, the servo motor of the first drive mechanism 61 is configured outside the execution arm 31 and the Z-axis mounting component 2; the servo motor of the second drive mechanism 62 is configured inside the Z-axis mounting component 2; the servo motors in the third drive mechanism 63 and the fourth drive mechanism 64 are respectively located on the side closer to the front end of the middle arm 312 and the forearm 313, so that the servo motor of each drive mechanism 6 is installed closer to the side of the base 1, thereby bringing the overall center of the robotic arm assembly 3 closer to the base 1, improving the stability of the robotic arm assembly 3, and thus reducing the droop of the end effector 4.

[0123] Furthermore, such as Figure 7 As shown, a tensioning wheel 8 is also provided on the transmission path between the reducer 7 and the end effector 4, and its position can be adjusted according to actual needs. When the fourth drive mechanism 64 is started, the servo motor of the fourth drive mechanism 64 starts to rotate, and drives the reducer 7 to rotate through the friction of the conveyor belt. The reducer 7 then transmits the power to the input shaft of the end effector 4 through the belt. During this process, the tensioning wheel 8 adjusts the tension of the conveyor belt by adjusting its position to ensure that the conveyor belt is always in a suitable tension state, so as to transmit the power to the end effector 4 stably and efficiently, and drive the end effector 4 to rotate.

[0124] In a belt drive system, insufficient belt tension reduces friction between the belt and the power output end, intermediate pulley, and input shaft of the end effector 4, leading to slippage. The tensioning pulley 8 effectively adjusts the belt tension, ensuring it remains at a suitable tension. This increases friction between the belt and the pulleys, preventing slippage and ensuring the stable and reliable transmission of power from the fourth drive mechanism 64 to the end effector 4, allowing it to rotate at a predetermined speed and torque. Furthermore, appropriate belt tension reduces elastic slippage during transmission, minimizing transmission errors. Elastic slippage causes uneven power transmission, resulting in fluctuations in the rotational speed of the end effector 4. The tensioning pulley 8, by adjusting the tension, makes the belt transmission smoother, reducing fluctuations, improving transmission accuracy, and preventing vibration of the end effector 4.

[0125] The above embodiments are merely illustrative of the technical concept and features of the present invention, intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and should not be construed as limiting the scope of protection of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of the present invention is defined by the appended claims rather than the foregoing description, and thus all changes falling within the meaning and scope of the equivalents of the claims are intended to be included within the present invention.

Claims

1. A control method of a multi-track wafer handling robot, characterized by, The mechanical arm assembly and the end effector are used to perform actions, wherein the mechanical arm assembly comprises three sequentially rotating connected execution arms, the execution arms are sequentially forearm, middle arm and small arm from the base to the end effector; the end effector is installed at the end position of the execution arm farthest from the base, and is configured to be able to rotate around the connection; The method is as follows: S1: safety area setting: the three execution arms are always in the safety area during movement; S2: trajectory planning: iteratively calculate the coordinates of each point from the boundary to the center in the safety area, and generate a safety link; from the three obstacle end points P1, Q1, R1 to the origin O, a discrete point set is generated; By calculating the minimum distance M of the projection of each point on the three obstacle sides, the safety path points are screened; P1...P n , Q1...Q n , R1...R n three different position links, and a quadratic polynomial is used for local fitting of the discrete points to generate a smooth safety link curve; S3: end effector path planning: in a safe link, the end effector is always towards the station position, and the center of the end effector is moved along the safe link, the angles a, b, c between each point and the adjacent arm, and the angle d between the forearm and the end effector are calculated; select P i P j , Q i Q j , R i R j The link where the point closest to the origin O is located; when the coordinates (x, y) and the attitude Y of the forearm end are taught or designed in advance, and the distance between the forearm end and the forearm end is C, the calculation formula of each angle is as follows: ; ; ; ; a: the angle between the forearm and the x-axis; b: the angle between the forearm and the middle arm; c: the angle between the middle arm and the small arm; d: the angle between the small arm and the end effector; W: the distance between the small arm end coordinates (x, y) and the origin O; B: the length of the small arm, middle arm and forearm; S4: optimal C value calculation: traverse optimization is performed on the distance C in step S3, and the optimal C value is found; S5: optimal time according to optimal C value: when the maximum speed, maximum acceleration and maximum jerk of the end effector are greater than the threshold value, the total time increases by 50%, and when the maximum speed, maximum acceleration and maximum jerk of the end effector are less than the threshold value, the total time decreases by 50%.

2. The control method of a multi-track wafer handling robot according to claim 1, wherein: Step S2 includes the following sub-steps: S2.1: obstacle boundary iteration: set three boundary obstacle end points as P1, Q1 and R1, respectively, and iteratively calculate from P1, Q1 and R1 to the origin O with a spacing of 5mm; S2.2: SBPLX optimization: Set , call SBPLX numerical optimization algorithm to get the position links of P1...P n , Q1...Q n , R1...R n ; S2.2.1: calculate the next point P(i+1) and the projection point M of the three obstacles: ； A1, A2, A3, A4: four corner coordinates of the first obstacle; B1, B2, B3, B4: four corner coordinates of the second obstacle; C1, C2, C3, C4: four corner coordinates of the third obstacle; : coefficient, value range [0, 1] S2.2.2: Using SBPLX numerical optimization algorithm, the angle between the next point and the previous point is optimized to maximize the minimum distance from the above 5 points to P(i+1), and P1...P n , Q1...Q n , R1...R n position link; S2.3: using a quadratic polynomial, locally curve fitting is performed on the above position link, the points are projected onto the curve, and a smooth safety link curve is obtained.

3. The control method of a multi-track wafer handling robot according to claim 2, wherein: Step S4 includes the following steps: S4.1: set the initial value C=B, and import the C value into the second derivative of a, b and c, so that the corresponding second derivatives are equal to a constant, and calculate the mean square error of each ratio; S4.2: use CGAL geometric algorithm to judge whether it collides with the obstacle, if it collides, return the maximum value, if it does not collide, return the mean square error; S4.3: use COBYLA numerical optimization algorithm to automatically find the optimal C value.

4. A multi-track wafer handling robot for use in a method of controlling a multi-track wafer handling robot as claimed in any one of claims 1 to 3, characterized in that It includes: The base (1) and the Z-axis mounting member (2) penetrating through the base (1), the Z-axis mounting member (2) has a mounting plane (21) perpendicular to the Z-axis; The mechanical arm assembly (3) comprises three sequentially rotating connected execution arms (31), the front end is carried and fixed on the mounting plane (21), and has an applied locking force; At least one end effector (4) is installed at the end position of the execution arm (31) farthest from the base (1) and is configured to be able to rotate around the connection; Wherein, the base (1) and the Z-axis mounting (2) are provided with a shaft ring structure (5) to limit the sag of the end of the mechanical arm assembly (3).

5. The multi-track wafer handling robot of claim 4, wherein: The execution arm (31) is sequentially a forearm (311), a middle arm (312) and a small arm (313) from the base (1) to the end effector (4); the forearm (311), the middle arm (312), the small arm (313) and the end effector (4) each have an independent driving mechanism (6).

6. The multi-track wafer handling robot of claim 5, wherein: The forearm (311) is provided with a first driving mechanism (61), and the output end of the first driving mechanism (61) is fixedly connected with the Z-axis mounting (2); The middle arm (312) is provided with a second driving mechanism (62) and is distributed in the Z-axis mounting (2) and the forearm (311); The small arm (313) is provided with a third driving mechanism (63) and is distributed in the middle arm (312); The end effector (4) is provided with a fourth driving mechanism (64) and is distributed in the small arm (313).

7. The multi-track wafer handling robot of claim 6, wherein: The first driving mechanism (61), the second driving mechanism (62), the third driving mechanism (63) and the fourth driving mechanism (64) each adopt a combination of a servo motor and a transmission belt; The servo motor of the first driving mechanism (61) is arranged outside the execution arm (31) and the Z-axis mounting (2); The servo motor of the second driving mechanism (62) is arranged in the Z-axis mounting (2); The servo motors in the third driving mechanism (63) and the fourth driving mechanism (64) are respectively arranged in the middle arm (312) and the small arm (313) close to the front end.

8. The multi-track wafer handling robot of claim 7, wherein: The end effector (4) is provided with two groups, and correspondingly has two groups of the fourth driving mechanism (64); The servo motors of the two groups of the fourth driving mechanism (64) are distributed along the width direction of the small arm (313) and are connected with integrated reducers (7) through transmission belts, the two groups of reducers (7) are distributed along the length direction of the small arm (313), and the output end of the reducer (7) is also connected with the input end of the end effector (4) through a transmission belt.

9. The multi-track wafer handling robot as set forth in claim 4, further comprising: A plurality of locking members (9) are arranged between the forearm (311) and the Z-axis mounting (2), the plurality of locking members (9) are annularly distributed, and mechanical pre-tightening force is applied to eliminate or reduce the assembly gap at the connection between the forearm (311) and the Z-axis mounting (2), so as to inhibit the inclination of the forearm (311) caused by the force generated by the self-weight of the small arm (313) and the end effector (4) thereof.

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