A constant force grinding device for fan blade surface and control method thereof

Abstract

The present invention relates to a constant force grinding device for the surface of a wind turbine blade, comprising a hoisting mechanism, a rotor adjustment unit, a suction cup unit, an overall support frame, a six-degree-of-freedom collaborative robot, a six-dimensional force sensor, a robot controller, and a constant force grinding unit; the present invention also relates to a constant force grinding control method: the six-degree-of-freedom collaborative robot controls the constant force grinding unit to grind according to a predetermined trajectory, and obtains a grinding force simulation signal; based on the grinding force simulation signal and the expected force signal, the force error is calculated as the input of the force controller; the force controller outputs a servo valve control quantity, and at the same time transmits the signal collected by the distance sensor to the robot controller, and then compensates through a posture compensation algorithm to achieve constant force grinding. Compared with the prior art, the present invention can achieve constant force control for grinding high-altitude wind turbine blades, reduce the risk of manual operation, improve the efficiency of high-altitude blade repair, and ensure grinding quality. Its reasonable structure makes it more suitable for mass production.

Description

Technical Field

[0001] The present invention relates to the technical field of power transmission engineering, and in particular to a constant-force grinding device for a fan blade surface and a control method thereof. Background Art

[0002] With the rapid development of the global economy, humanity's demand for energy continues to increase. In recent years, energy resources have become increasingly depleted and the environment has continued to deteriorate. Therefore, wind energy has seen sustained and rapid development around the world due to its environmentally friendly, low-carbon nature, short construction cycles, renewable nature, and low environmental requirements. As a clean and renewable energy source, wind energy has become increasingly popular and valued.

[0003] Wind turbines, the primary source of wind power today, are devices that convert wind energy into electricity. They occupy minimal land, pose little social risk, are environmentally friendly, and can be rapidly scaled up and industrialized. To date, they offer the highest economic returns among developed renewable energy sources.

[0004] Wind turbine equipment maintenance and repair are currently receiving significant attention, particularly for high-altitude blade repair, which currently relies primarily on manual labor. Manual repair of high-altitude wind turbine blades is a high-risk task, as they are often located at high altitudes, such as hills, coastlines, and high-rise buildings, where they can easily cause casualties or physical injury.

[0005] At present, it is a new trend to use robots for high-altitude repair to replace manual repair of wind turbine blades. Compared with manual repair of high-altitude blades, robot repair has the advantages of high safety, high efficiency, high precision, strong repeatability, and strong programmability. Through robot repair, not only can efficient, accurate and repeatable repair of wind turbine blades be achieved, but also the safety and work efficiency of workers can be improved, and maintenance costs can be reduced. There are also the following problems when grinding blades at high altitude: (1) The blades will swing slightly due to factors such as wind force. In this way, when the robot is grinding the damaged part of the blade, the end grinder will deviate from the surface area of ​​the wind turbine blade to be polished; (2) The pneumatic constant force device currently suitable for collaborative robots will overcut when encountering external force interference during the grinding process, and cannot meet the expected requirements.

[0006] Patent CN204584912U discloses a wind turbine blade grinding device, including a mobile platform, a guide rail and a manipulator placed on the mobile platform. The manipulator includes four articulated arms, a grinding wheel and a sensor. Each joint is connected to a joint motor. A rotating grinding wheel for grinding and an infrared sensor and a pressure sensor for detecting the position of the grinding wheel are installed at the end of the terminal articulated arm. The manipulator has good flexibility and high grinding efficiency, but it cannot solve technical problems such as overcutting when encountering external force interference, and cannot achieve constant force control. Summary of the Invention

[0007] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a constant force grinding device for the surface of a wind turbine blade and a control method thereof. The device is suitable for the shaping step in the repair process of high-altitude wind turbine blades. It has a simple structure and a lightweight design. Combined with the control method and the posture compensation algorithm, it can better maintain constant force control at the end during the grinding operation, thereby maintaining the stability of the blade grinding and laying a good foundation for subsequent repair operations.

[0008] The purpose of the present invention can be achieved by the following technical solutions:

[0009] The present invention provides a constant force grinding device for the surface of a wind turbine blade, comprising: a constant force grinding unit, a six-dimensional force sensor, a six-degree-of-freedom collaborative robot, a robot controller, a hoisting mechanism, a suction cup unit, an overall support frame, and a rotor adjustment unit;

[0010] The hoisting mechanism is arranged on one side of the upper surface of the overall support frame, and is used to hoist the constant force grinding device to the vicinity of the high-altitude blade;

[0011] The six-degree-of-freedom collaborative robot is located on the other side of the upper surface of the overall support frame. The six-degree-of-freedom collaborative robot is used to control the constant force grinding unit to perform grinding operations according to a pre-set trajectory;

[0012] The suction cup unit is arranged on the lower surface of the overall support frame and is used to absorb the fan blades;

[0013] The rotor adjustment units are symmetrically arranged on both sides of the lower surface of the overall support frame for stability adjustment;

[0014] One end of the six-dimensional force sensor is connected to the end of the six-degree-of-freedom collaborative robot, and the other end is connected to the constant force grinding unit. The six-dimensional force sensor is used to obtain the grinding force analog signal of the constant force grinding unit, calculate the force error based on the grinding force analog signal and the expected force signal, and send the force error signal to the force controller. The force controller sends the force control amount signal to the constant force grinding unit and sends the signal collected from the constant force grinding unit to the robot controller;

[0015] The robot controller is located on the upper surface of the overall support frame and is used to receive the signal sent by the force sensor, calculate the end control amount through the posture compensation algorithm, and send the end control amount signal to the constant force grinding unit through the force controller for compensation.

[0016] Furthermore, the constant force grinding unit includes: an adaptive compliance unit, an adjustable hydraulic buffer unit, and a grinding motor. The adaptive compliance unit is fixed under the six-dimensional force sensor, the adjustable hydraulic buffer unit is fixed under the adaptive compliance unit, and the grinding motor is fixed under the adjustable hydraulic buffer unit.

[0017] Furthermore, the adaptive compliance unit includes an adaptive compliance unit upper cover, an adaptive compliance unit dust cover, a roller spline mechanism, a servo valve, a distance sensor, an adaptive compliance unit lower cover, a cylinder connecting plate, and a cylinder. The telescopic rod of the cylinder is connected to the cylinder connecting plate and the adaptive compliance unit lower cover in sequence. The distance sensor is fixed on the adaptive compliance unit lower cover, the transmission mechanism is fixed on the adaptive compliance unit upper cover, the transmission mechanism is fixedly connected to the cylinder connecting plate, the servo valve is fixedly connected to the cylinder connecting plate, and the servo valve receives an electrical signal from a control system as input and controls the movement of the actuator by adjusting the hydraulic flow.

[0018] When external force interferes during grinding, the six-dimensional force sensor obtains the grinding force analog signal and transmits it to the force controller. The force controller sends a control signal to the constant force grinding unit. At this time, the servo valve receives the control signal to control the cylinder to extend and retract, realizing adaptive and flexible control. At the same time, the signal collected by the distance sensor is transmitted to the robot controller to run the posture compensation algorithm.

[0019] Furthermore, the transmission mechanism is a roller spline mechanism.

[0020] Furthermore, the spline sleeve of the roller spline mechanism is fixed on the upper cover of the adaptive compliance unit, and the spline telescopic rod and the servo valve of the roller spline mechanism are fixedly connected to the cylinder connecting plate.

[0021] Furthermore, there are three transmission mechanisms.

[0022] Furthermore, the adjustable hydraulic buffer unit includes: a buffer upper cover, a buffer dust cover, a buffer lower cover, and an adjustable hydraulic buffer. One end of the adjustable hydraulic buffer is fixedly connected to the buffer upper cover, and the other end is fixedly connected to the buffer lower cover, and is arranged in the buffer dust cover. The adjustable hydraulic buffer is used to control the impact and vibration of the object during movement, and uses the damping characteristics of the liquid to slow down or eliminate the impact and vibration generated during the movement of the object. During grinding operations, if a large impact is suddenly received, the adjustable hydraulic buffer in the adjustable hydraulic buffer unit plays the most direct buffering role to prevent overcutting. At the same time, it can effectively protect the robot to prevent the joints from being greatly impacted and thus damaging the collaborative robot.

[0023] Furthermore, the grinding motor includes: a grinding motor housing, a motor, a motor shaft, a connector, and a grinding head. The motor is arranged in the grinding motor housing, and the motor is connected to the connector and the grinding head in sequence through the motor shaft.

[0024] The present invention also provides a method for controlling constant-force grinding of a fan blade surface, comprising the following steps:

[0025] S1: The rotor adjustment unit and the suction cup unit adsorb the entire fan blade surface constant force grinding device onto the fan blade. After the fan blade surface constant force grinding device is fixed on the high-altitude fan blade, the six-degree-of-freedom collaborative robot grinds the blade area to be polished according to the pre-set trajectory;

[0026] S2: The six-dimensional force sensor obtains the grinding force analog signal of the constant force grinding unit;

[0027] S3: The six-dimensional force sensor calculates the grinding force error and error change value based on the current expected force signal and the collected force simulation signal, and uses it as the input signal of the force controller;

[0028] S4: The force controller sends the force control signal to the constant force grinding unit. The force controller outputs the servo valve control signal. The servo valve controls the cylinder to perform telescopic movement. At the same time, the signal collected by the distance sensor is transmitted to the robot controller. The robot controller receives the signal sent by the force sensor, calculates the end control signal through the posture compensation algorithm, and sends the end control signal to the constant force grinding unit through the force controller for compensation to achieve constant force grinding.

[0029] The algorithm flow of the posture compensation algorithm in S4 is as follows:

[0030] The constant force grinding device is installed at the center point of the robot tool, and the coordinate system {t1} is established at the center point of the grinding motor. h2 is the distance from the end of the constant force grinding unit to the center point of the grinding motor, and h1 is the distance from the center point of the robot tool to the center point of the grinding motor. The cylinder contracts and the adjustable distance of the cylinder is Z. f , h1 follows Z f , which is expressed as:

[0031] h1=f(Z f )=Z f +a,0≤Z f ≤bwhere a and b are constants.

[0032] The transformation from the TCP coordinate system {tcp} to the center point of the grinding motor is a translation transformation, expressed as:

[0033]

[0034] When the cylinder is compressed, h1 changes ΔZ f When , the coordinates are expressed as:

[0035]

[0036] The posture compensation algorithm determines whether it is necessary to perform the compensation based on the size of the displacement deviation. The judgment method is as follows:

[0037] Assume that the blade grinding path based on the blade coordinate system {obj} is generated by a constant force grinding device, T obj The target posture of the blade to be polished by the constant force polishing device is T obj The target position T2 of the constant force grinding device in the world coordinate system is converted by coordinate transformation and compared with the current feedback position of the constant force grinding device. Through motion planning, the motion control amount D of the end point can be obtained. When the cylinder displacement is small, let ΔZ f =0, then the terminal control amount is:

[0038] D=D1=[d x ,d y ,d z ,δ x ,δ y ,δ z ] T .

[0039] When the cylinder displacement is large, ΔZ f ≠0, the deviation value is transmitted to the robot controller to compensate the end position. By compensating the Z axis, the end control amount is:

[0040] D=D2=[d x ,d y ,d z +ΔZ f ,δ x ,δ y ,δ z ] T .

[0041] Since the differential motion of the end point of the constant force grinding unit and the differential motion of each joint can be expressed as:

[0042] D=JD θ , so, D θ =J -1 D.

[0043] Thereby achieving constant force grinding of the fan blade surface.

[0044] Compared with the prior art, the present invention has the following advantages:

[0045] (1) The present invention designs a constant force grinding device, obtains real-time grinding signals through a force sensor, and combines a force controller with a posture compensation algorithm to achieve constant force control during grinding, thereby improving the quality of blade grinding.

[0046] (2) The present invention adds an adjustable hydraulic buffer device to the constant force grinding device, which can play a buffering role between the grinding motor and the adaptive compliance device when subjected to a large impact to prevent overcutting. At the same time, it can effectively protect the robot to prevent the joints from being greatly impacted and thus damaging the collaborative robot.

[0047] (3) The present invention improves the efficiency of blade grinding, ensures the quality of blade grinding, improves and saves costs, and replaces manual labor in dangerous high-altitude blade grinding work.

[0048] (4) Simple structure and lightweight design. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a structural schematic diagram of a constant force grinding device for the surface of a wind turbine blade.

[0050] Figure 2 This is a structural diagram of the constant force grinding unit.

[0051] Figure 3 Schematic diagram of the structure of the adaptive compliance unit.

[0052] Figure 4 This is the exploded view of the adaptive compliant element.

[0053] Figure 5 It is a structural diagram of the adjustable hydraulic buffer unit.

[0054] Figure 6 This is a schematic diagram of the structure of the grinding motor.

[0055] Figure 7 The schematic diagram of the control method.

[0056] Figure 8 This is the flowchart of the posture compensation algorithm.

[0057] Reference numerals: 1. Constant force grinding unit; 2. Six-dimensional force sensor; 3. Six-degree-of-freedom collaborative robot; 4. Robot controller; 5. Hoisting mechanism; 6. Suction cup unit; 7. Overall support frame; 8. Rotor adjustment unit; 1-1. Adaptive compliance unit; 1-2. Adjustable hydraulic buffer unit; 1-3. Grinding motor; 1-1-1. Adaptive compliance unit cover; 1-1-2. Adaptive compliance unit dust cover; 1-1-3. Roller spline mechanism; 1-1 -4, servo valve; 1-1-5, distance sensor; 1-1-6, adaptive compliance unit lower cover; 1-1-7, cylinder connecting plate; 1-1-8, cylinder; 1-2-1, buffer upper cover; 1-2-2, buffer dust cover; 1-2-3, buffer lower cover; 1-2-4, adjustable hydraulic buffer; 1-3-1, grinding motor housing; 1-3-2, motor; 1-3-3, motor shaft; 1-3-4, connector; 1-3-5, grinding head. DETAILED DESCRIPTION

[0058] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms, and other features not explicitly described in this technical solution are considered common technical features disclosed in the prior art.

[0059] Example 1

[0060] like Figure 1 As shown, this example provides a constant force grinding device for the surface of a wind turbine blade, including: a constant force grinding unit 1, a six-dimensional force sensor 2, a six-degree-of-freedom collaborative robot 3, a robot controller 4, a lifting mechanism 5, a suction cup unit 6, an overall support frame 7, and a rotor adjustment unit 8.

[0061] The upper surface of the overall support frame 7 is provided with a robot controller 4, a six-degree-of-freedom collaborative robot 3, and a lifting mechanism 5, and the lower surface of the overall support frame 7 is provided with a suction cup unit 6 and a rotor adjustment unit 8; one end of the six-dimensional force sensor 2 is connected to the six-degree-of-freedom collaborative robot 3, and the other end of the six-dimensional force sensor 2 is connected to the constant force grinding unit 1.

[0062] The entire constant force grinding device for the surface of the wind turbine blade is brought to the vicinity of the high-altitude blade through the lifting mechanism 5, and the entire constant force grinding device for the surface of the wind turbine blade is adsorbed on the wind turbine blade in combination with the rotor adjustment unit 8 and the suction cup unit 6. The constant force grinding unit 1 is then controlled by the six-degree-of-freedom collaborative robot 3 to perform grinding operations according to a predetermined trajectory. One end of the six-dimensional force sensor 2 is connected to the end of the six-degree-of-freedom collaborative robot 3, and the other end is connected to the constant force grinding unit 1. The six-dimensional force sensor 2 is used to obtain the grinding force analog signal of the constant force grinding unit 3, calculate the force error according to the grinding force analog signal and the expected force signal, and send the force error signal to the force controller. The force controller sends the force control signal to the constant force grinding unit 1, and sends the signal collected from the constant force grinding unit 1 to the robot controller 4.

[0063] The robot controller 4 is arranged on the upper surface of the overall support frame 7, and is used to receive the signal sent by the force sensor, calculate the end control amount through the posture compensation algorithm, and send the end control amount signal to the constant force grinding unit 1 through the force controller for compensation.

[0064] like Figure 2 As shown, the constant force grinding unit 1 includes: an adaptive compliance unit 1-1, an adjustable hydraulic buffer unit 1-2, and a grinding motor 1-3. The adaptive compliance unit 1-1 is fixed below the six-axis force sensor 2, the adjustable hydraulic buffer unit 1-2 is fixed below the adaptive compliance unit 1-1, and the grinding motor 1-3 is fixed below the adjustable hydraulic buffer unit 1-2.

[0065] like Figure 3 、 Figure 4 As shown, the adaptive compliance unit 1-1 includes an adaptive compliance unit upper cover 1-1-1, an adaptive compliance unit dust cover 1-1-2, a roller spline mechanism 1-1-3, a servo valve 1-1-4, a distance sensor 1-1-5, an adaptive compliance unit lower cover 1-1-6, a cylinder connecting plate 1-1-7, and a cylinder 1-1-8. The telescopic rod of cylinder 1-1-8 is connected to the cylinder connecting plate 1-1-7 and the adaptive compliance unit lower cover 1-1-6 in sequence. The distance sensor 1-1-5 is fixed to the adaptive compliance unit lower cover 1-1-6. There are three roller spline mechanisms 1-1-3. The spline sleeve of the roller spline mechanism 1-1-3 is fixed to the adaptive compliance unit upper cover 1-1-1. The spline telescopic rod of the roller spline mechanism 1-1-3 and the servo valve 1-1-4 are fixedly connected to the cylinder connecting plate 1-1-7.

[0066] When external force interferes during grinding, the six-dimensional force sensor 2 obtains the grinding force analog signal and transmits it to the force controller. The force controller sends a control signal to the constant force grinding unit 1. At this time, the servo valve 1-1-4 receives the control signal to control the cylinder 1-1-8 to extend and retract, realizing adaptive and flexible control. At the same time, the signal collected by the distance sensor 1-1-5 is transmitted to the robot controller 4 for the posture compensation algorithm to run.

[0067] like Figure 5 As shown, the adjustable hydraulic buffer unit 1-2 includes: a buffer upper cover 1-2-1, a buffer dust cover 1-2-2, a buffer lower cover 1-2-4, and an adjustable hydraulic buffer 1-2-3. One end of the adjustable hydraulic buffer 1-2-3 is fixedly connected to the buffer upper cover 1-2-1, and the other end is fixedly connected to the buffer lower cover 1-2-4, and is located in the buffer dust cover 1-2-2.

[0068] During grinding operations, if a large impact is suddenly applied, the adjustable hydraulic buffer 1-2-3 in the adjustable hydraulic buffer unit 1-2 plays the most direct buffering role to prevent overcutting. At the same time, it can effectively protect the robot to prevent the joints from being greatly impacted and thus damaging the collaborative robot.

[0069] like Figure 6 As shown, the grinding motor 1-3 includes a grinding motor housing 1-3-1, a motor 1-3-2, a motor shaft 1-3-3, a connector 1-3-4, and a grinding head 1-3-5. The motor 1-3-2 is disposed within the grinding motor housing 1-3-1 and is connected to the connector 1-3-4 and the grinding head 1-3-5 in sequence via the motor shaft 1-3-3.

[0070] This example also provides a control method for constant force grinding of the fan blade surface, such as Figure 7 As shown, the following steps are included:

[0071] S1: The rotor adjustment unit 8 and the suction cup unit 6 adsorb the entire fan blade surface constant force grinding device onto the fan blade. After the fan blade surface constant force grinding device is fixed on the high-altitude fan blade, the six-degree-of-freedom collaborative robot 3 grinds the blade area to be polished according to the pre-set trajectory;

[0072] S2: The six-dimensional force sensor 2 obtains the grinding force analog signal of the constant force grinding unit 1;

[0073] S3: The six-dimensional force sensor 2 calculates the grinding force error and error change value based on the current expected force signal and the collected force simulation signal, and uses it as the input signal of the force controller;

[0074] S4: The force controller sends the force control quantity signal to the constant force grinding unit 1. The force controller outputs the servo valve control quantity. The servo valve 1-1-4 controls the cylinder 1-1-8 to perform telescopic movement. At the same time, the signal collected by the distance sensor 1-1-5 is transmitted to the robot controller 4. The robot controller 4 receives the signal sent by the force sensor, calculates the end control quantity through the posture compensation algorithm, and sends the end control quantity signal to the constant force grinding unit 1 through the force controller for compensation to achieve constant force grinding.

[0075] like Figure 8 As shown in the figure, the algorithm flow of the posture compensation algorithm is as follows:

[0076] The constant force grinding device is installed at the center point of the robot tool, and the coordinate system {t1} is established at the center point of the grinding motor 1-3. h2 is the distance from the end of the constant force grinding unit 1 to the center point of the grinding motor 1-3, and h1 is the distance from the center point of the robot tool to the center point of the grinding motor 1-3. The cylinder 1-1-8 is retracted, and the adjustable distance of the cylinder 1-1-8 is Z f , h1 follows Z f , which is expressed as:

[0077] h1=f(Z f )=Z f +a,0≤Z f ≤bwhere a and b are constants.

[0078] The transformation from the TCP coordinate system {tcp} to the center point of the grinding motor 1-3 is a translation transformation, expressed as:

[0079]

[0080] When cylinder 1-1-8 is compressed, h1 changes ΔZ f When , the coordinates are expressed as:

[0081]

[0082] The posture compensation algorithm determines whether it is necessary to perform the compensation based on the size of the displacement deviation. The judgment method is as follows:

[0083] Assume that the blade grinding path based on the blade coordinate system {obj} is generated by a constant force grinding device, T obj The target posture of the blade to be polished by the constant force polishing device is T obj The target position T2 of the constant force grinding device in the world coordinate system is converted by coordinate transformation and compared with the current feedback position of the constant force grinding device. Through motion planning, the motion control amount D of the end point can be obtained. When the displacement of cylinder 1-1-8 is small, let ΔZ f =0, then the terminal control amount is:

[0084] D=D1=[d x ,d y ,d z ,δ x ,δ y ,δ z ] T .

[0085] When the displacement of cylinder 1-1-8 is large, ΔZ f ≠0, the deviation value is transmitted to the robot controller 4 to compensate the end position. By compensating the Z axis, the end control amount is:

[0086] D=D2=[d x ,d y ,d z +ΔZ f ,δ x ,δ y ,δ z ] T .

[0087] Since the differential motion of the end point of the constant force grinding unit 1 and the differential motion of each joint can be expressed as:

[0088] D=JD θ , so, D θ =J -1 D.

[0089] Thereby achieving constant force grinding of the fan blade surface.

[0090] The above description of the embodiments is intended to facilitate understanding and use of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention, without departing from the scope of the present invention, should be within the scope of protection of the present invention.

Claims

1. A constant force grinding device for the surface of a fan blade, characterized in that: include: Constant force grinding unit (1), six-dimensional force sensor (2), six-degree-of-freedom collaborative robot (3), robot controller (4), lifting mechanism (5), suction cup unit (6), overall support frame (7), rotor adjustment unit (8); The hoisting mechanism (5) is provided on one side of the upper surface of the overall support frame (7), and the hoisting mechanism (5) is used to hoist the constant force grinding device near the high-altitude blade; The six-degree-of-freedom collaborative robot (3) is arranged on the other side of the upper surface of the overall support frame (7), and the six-degree-of-freedom collaborative robot (3) is used to control the constant-force grinding unit (1) to perform grinding operations according to a preset trajectory; The suction cup unit (6) is provided on the lower surface of the overall support frame (7) and is used for adsorbing the fan blades; The rotor adjustment unit (8) is symmetrically arranged on both sides of the lower surface of the overall support frame (7) and is used to adjust the stability of the constant force grinding device; One end of the six-dimensional force sensor (2) is connected to the end of the six-degree-of-freedom collaborative robot (3), and the other end is connected to the constant-force grinding unit (1). The six-dimensional force sensor (2) is used to obtain a grinding force analog signal of the constant-force grinding unit (1), calculate a force error based on the grinding force analog signal and a desired force signal, and send the force error signal to a force controller. The force controller sends a force control amount signal to the constant-force grinding unit (1), and sends the signal collected from the constant-force grinding unit (1) to the robot controller (4); The constant force grinding unit (1) comprises: an adaptive compliance unit (1-1), an adjustable hydraulic buffer unit (1-2), and a grinding motor (1-3); the adaptive compliance unit (1-1) is fixed below the six-dimensional force sensor (2); the adjustable hydraulic buffer unit (1-2) is fixed below the adaptive compliance unit (1-1); and the grinding motor (1-3) is fixed below the adjustable hydraulic buffer unit (1-2); The adaptive compliance unit (1-1) comprises an adaptive compliance unit upper cover (1-1-1), an adaptive compliance unit dust cover (1-1-2), a roller spline mechanism (1-1-3), a servo valve (1-1-4), a distance sensor (1-1-5), an adaptive compliance unit lower cover (1-1-6), a cylinder connecting plate (1-1-7), and a cylinder (1-1-8); the telescopic rod of the cylinder (1-1-8) is sequentially connected to the cylinder connecting plate (1-1-7) and the adaptive compliance unit lower cover (1-1-6); the distance sensor (1-1-5) is fixed to the adaptive compliance unit lower cover (1-1-6); a transmission mechanism is fixed to the adaptive compliance unit upper cover (1-1-1); the transmission mechanism is fixedly connected to the cylinder connecting plate (1-1-7); and the servo valve (1-1-4) is fixedly connected to the cylinder connecting plate (1-1-7); The robot controller (4) is arranged on the upper surface of the overall support frame (7), and is used to receive the signal sent by the force sensor, calculate the end control amount through the posture compensation algorithm, and send the end control amount signal to the constant force grinding unit (1) through the force controller for compensation; The specific process of the posture compensation algorithm includes: A coordinate system {t1} is established at the center point of the grinding motor (1-3), wherein h2 is the distance from the end of the constant force grinding unit (1) to the center point of the grinding motor (1-3), h1 is the distance from the center point of the robot tool to the center point of the grinding motor (1-3), the cylinder (1-1-8) is contracted, and the adjustable distance of the cylinder (1-1-8) is Z f , h1 follows Z f , which is expressed as: h1=f(Z f )=Z f +a,0≤Z f ≤b, where a and b are constants; The transformation from the TCP coordinate system {tcp} to the center point of the grinding motor (1-3) is a translation transformation, which is expressed as: When the cylinder (1-1-8) is compressed, h1 changes by ΔZ f When , the coordinates are expressed as: Before the posture compensation algorithm is executed, the size of the displacement deviation is used to determine whether the posture compensation algorithm is needed. The judgment method is as follows: Assume that the blade grinding path based on the blade coordinate system {obj} is generated by a constant force grinding device, T obj The target posture of the blade to be polished by the constant force polishing device is T obj The target position T2 of the constant force grinding device in the world coordinate system is converted into the coordinate transformation, and compared with the current feedback position of the constant force grinding device, the motion control amount D of the end point is obtained through motion planning; when the displacement of the cylinder (1-1-8) is small, ΔZ f =0, then the terminal control amount is: D=D1=[d x ,d y ,d z ,d x ,d y ,d z ] T ; When the displacement of the cylinder (1-1-8) is large, ΔZ f ≠0, the deviation value is transmitted to the robot controller (4) to compensate the terminal posture. By compensating the Z axis, the terminal control amount is: D=D2=[d x ,d y ,d z +ΔZ f ,d x ,d y ,d z ] T ; D θ =J -1 D; Thereby achieving constant force grinding of the fan blade surface.

2. A constant force grinding device for the surface of a wind turbine blade according to claim 1, characterized in that: The transmission mechanism is a roller spline mechanism (1-1-3).

3. A constant force grinding device for the surface of a fan blade according to claim 2, characterized in that: The spline sleeve of the roller spline mechanism (1-1-3) is fixed on the upper cover (1-1-1) of the adaptive compliance unit, and the spline telescopic rod and the servo valve (1-1-4) of the roller spline mechanism (1-1-3) are both fixedly connected to the cylinder connecting plate (1-1-7).

4. A constant force grinding device for the surface of a wind turbine blade according to claim 1, characterized in that: There are three transmission mechanisms.

5. A constant force grinding device for the surface of a wind turbine blade according to claim 1, characterized in that: The adjustable hydraulic buffer unit (1-2) comprises: a buffer upper cover (1-2-1), a buffer dust cover (1-2-2), a buffer lower cover (1-2-3), and an adjustable hydraulic buffer (1-2-4); one end of the adjustable hydraulic buffer (1-2-4) is fixedly connected to the buffer upper cover (1-2-1), and the other end is fixedly connected to the buffer lower cover (1-2-3), and is arranged in the buffer dust cover (1-2-2).

6. A constant force grinding device for the surface of a wind turbine blade according to claim 1, characterized in that: The grinding motor (1-3) comprises: a grinding motor housing (1-3-1), a motor (1-3-2), a motor shaft (1-3-3), a connector (1-3-4), and a grinding head (1-3-5); the motor (1-3-2) is arranged in the grinding motor housing (1-3-1); and the motor (1-3-2) is connected to the connector (1-3-4) and the grinding head (1-3-5) in sequence through the motor shaft (1-3-3).

7. A method for constant force grinding of a fan blade surface using the grinding device according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1: The entire fan blade surface constant force grinding device is brought to the vicinity of the high-altitude blade by a hoisting mechanism, the rotor adjustment unit (8) and the suction cup unit (6) adsorb the entire fan blade surface constant force grinding device on the fan blade, and after the fan blade surface constant force grinding device is fixed on the high-altitude fan blade, the six-degree-of-freedom collaborative robot (3) performs a grinding operation on the blade area to be polished according to a preset trajectory; S2: obtaining a grinding force analog signal of the constant force grinding unit (1) through a six-dimensional force sensor (2); S3: Calculate the grinding force error and error change value based on the current expected force signal and the collected force simulation signal through the six-dimensional force sensor (2), and use it as the input signal of the force controller; S4: The force control amount signal is sent to the constant force grinding unit (1) through the force controller, and the output of the force controller is the control amount of the servo valve (1-1-4) of the constant force grinding unit (1). The servo valve (1-1-4) controls the cylinder (1-1-8) of the constant force grinding unit (1) to perform telescopic movement. At the same time, the signal collected by the distance sensor (1-1-5) of the constant force grinding unit (1) is transmitted to the robot controller (4). The robot controller (4) receives the signal sent by the force sensor, calculates the end control amount through the posture compensation algorithm, and sends the end control amount signal to the constant force grinding unit (1) through the force controller for compensation, so as to achieve constant force grinding.

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