Mechanical automatic material taking device for photovoltaic construction and control method

Abstract

The invention discloses a mechanical automatic material taking device for photovoltaic construction and a control method. The mechanical automatic material taking device comprises a vertical tower body, a rotation driving device is arranged at the bottom of the vertical tower body, and a first telescopic oil cylinder is arranged on the vertical tower body; a horizontal arm is connected to the top of the vertical tower body, a second telescopic oil cylinder is arranged on the horizontal arm, a vertical arm is arranged at the end of the horizontal arm, the bottom of the vertical arm is hinged to a connecting piece, the connecting piece is hinged to a photovoltaic panel suction cup, and a third telescopic oil cylinder and a pitching oil cylinder are installed on the vertical arm; a rotating motor is arranged on the photovoltaic panel suction cup; a swing motor is arranged on the connecting piece; a rotation angle monitoring sensor is connected to the rotation driving device, a tower body height monitoring sensor is arranged on the vertical tower body, a horizontal arm amplitude monitoring sensor is arranged on the horizontal arm, a vertical arm telescopic monitoring sensor is arranged on the vertical arm, and a suction cup rotation angle monitoring sensor is arranged on the rotation motor. And a side swing angle and pitching angle monitoring sensor is arranged on the photovoltaic panel suction cup.

Description

Technical Field

[0001] The invention relates to a mechanical automatic material taking device for photovoltaic construction, and in particular to a mechanical automatic material taking device for photovoltaic construction and a control method thereof. Background Art

[0002] With the rapid development of the photovoltaic industry, the construction of photovoltaic power stations has accelerated. During the construction process, problems such as high labor intensity, lack of personnel, poor working environment, and low work efficiency have gradually emerged. In the prior art, many mechanical equipment for installing photovoltaic panels have appeared; for example, patent CN202310757270.6 discloses a photovoltaic panel grasping manipulator with a detection device, the base of which is a multi-axis manipulator, and also includes a grasping component and a detection component, the grasping component includes a grasping plane; the detection device includes a sensor base, a sensor, and a sliding component; the detection end of the sensor is connected to the sliding component; the sliding component includes a fixed block and a moving shaft, the moving shaft can slide in the sliding groove of the fixed block, and the lower end of the moving shaft has a detection plane. However, the inclination angle of the grasping component of the device cannot be adjusted, and how to achieve precision adjustment is not disclosed;

[0003] Patent CN202322429782.8 also discloses a photovoltaic panel manipulator grasping device, including a frame, a sliding sleeve slidably installed on the frame, a side slide rail installed on the front of the sliding sleeve, a sliding block slidably installed inside the side slide rail, a second cylinder installed on the top of the sliding block, a first cylinder installed on the front of the side slide rail, the output end of the first cylinder is fixedly connected to the sliding block, and a grasping assembly is installed at the bottom of the output end of the second cylinder; the grasping assembly includes a hanging plate installed on the output end of the second cylinder, a bottom plate is provided below the hanging plate, side arms are installed at equal angles on the outside of the bottom plate, a sliding groove is provided inside the side arm, a first slider is slidably installed inside the sliding groove, a suction cup is installed at the bottom end of the first slider, a negative pressure pump is installed on the hanging plate, and each suction cup is connected to the negative pressure pump through a hose; similarly, the inclination angle of the grasping assembly of the device cannot be adjusted, and how to achieve precision adjustment is not disclosed. Summary of the invention

[0004] In order to solve the technical problems existing in the prior art, the purpose of the present invention is to provide a mechanical automatic material taking device and a control method for photovoltaic construction.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] In the first aspect, the present invention provides a mechanical automatic material-grabbing device for photovoltaic construction, comprising a vertical tower body, a rotary drive device is arranged at the bottom of the vertical tower body, and a first telescopic cylinder is arranged on the vertical tower body; a horizontal arm is connected to the top of the vertical tower body, a second telescopic cylinder is arranged on the horizontal arm, a vertical arm is arranged at the end of the horizontal arm, the bottom of the vertical arm is hinged with a connecting piece, the connecting piece is hinged with the photovoltaic panel suction cup, and a third telescopic cylinder and a pitch cylinder are installed on the vertical arm; a rotating motor is arranged on the photovoltaic panel suction cup; a swing motor is arranged on the connecting piece; a rotation angle monitoring sensor is connected to the rotary drive device, a tower height monitoring sensor is arranged on the vertical tower body, a horizontal arm amplitude monitoring sensor is arranged on the horizontal arm, a vertical arm telescopic monitoring sensor is arranged on the vertical arm, and a suction cup rotation angle monitoring sensor is arranged on the rotary motor; and a side swing angle and pitch angle monitoring sensor are arranged on the photovoltaic panel suction cup.

[0007] As a further technical solution, the first telescopic oil cylinder comprises at least two stages of telescopic oil cylinders, and a first stage of telescopic oil cylinder drives a section of the tower body.

[0008] As a further technical solution, the second telescopic cylinder includes at least two stages of telescopic cylinders, and a first stage of the telescopic cylinder drives a horizontal arm.

[0009] As a further technical solution, the third telescopic cylinder includes at least two stages of telescopic cylinders, and a first stage of the telescopic cylinder drives a vertical arm.

[0010] As a further technical solution, the rotation angle monitoring sensor adopts an encoder.

[0011] As a further technical solution, the tower height monitoring sensor adopts a pull-wire sensor.

[0012] As a further technical solution, the horizontal arm amplitude monitoring sensor adopts a pull-wire sensor.

[0013] As a further technical solution, the vertical arm telescopic monitoring sensor adopts a pull-wire sensor.

[0014] As a further technical solution, a laser sensor is also provided on the photovoltaic panel suction cup for real-time detection of the distance between the suction cup and the photovoltaic panel.

[0015] As a further technical solution, the roll angle and pitch angle monitoring sensor adopts an LCA-T sensor.

[0016] As a further technical solution, the rotation angle monitoring sensor, tower height monitoring sensor, horizontal arm amplitude monitoring sensor, vertical arm telescopic monitoring sensor, laser sensor, and side swing angle and pitch angle monitoring sensors are all connected to a PLC controller, and the PLC controller controls the slewing drive device, the first telescopic cylinder, the second telescopic cylinder, the third telescopic cylinder, the pitch cylinder, the swing motor, and the rotating motor.

[0017] In a second aspect, the present invention is based on the above-mentioned mechanical automatic material taking device for photovoltaic construction, and further provides a method for controlling the mechanical automatic material taking device for photovoltaic construction using a PLC controller as follows:

[0018] Step 1, determine the photovoltaic panel assembly placement coordinates;

[0019] Step 2, detecting the current posture and position of the mechanical automatic material taking device according to the rotation angle monitoring sensor, tower height monitoring sensor, horizontal arm amplitude monitoring sensor, vertical arm telescopic monitoring sensor, laser sensor, and side swing angle and pitch angle monitoring sensor;

[0020] Step 3, the PLC controller compares the data collected in step 2 with the coordinates of step 1, and then drives the rotary drive device, the first telescopic cylinder, the second telescopic cylinder, the third telescopic cylinder, the pitch cylinder, the swing motor, and the rotating motor to perform corresponding actions according to the difference to achieve the grabbing of the photovoltaic panel assembly.

[0021] The beneficial effects of the present invention are as follows:

[0022] The mechanical automatic material-grabbing device for photovoltaic construction proposed in the present invention adopts a cantilever frame structure, that is, a rotary drive device is arranged at the bottom of the vertical tower body; the vertical tower body is arranged on the rotary drive device, and the top of the vertical tower body is connected with a horizontal arm; a vertical arm is arranged at the end of the horizontal arm, the bottom of the vertical arm is hinged with a connecting piece, the connecting piece is hinged with the photovoltaic panel suction cup, and a third telescopic cylinder and a pitch cylinder are installed on the vertical arm; a rotating motor is arranged on the photovoltaic panel suction cup; a swing motor is arranged on the connecting piece; large-height and long-range operations can be realized, and its operating range can basically cover the spatial installation requirements of most photovoltaic projects. At the same time, in this grabbing device, since the adjustment of the suction cup's subtle posture is close to the photovoltaic panel, the adjustment of the subtle posture movement does not rely on the root support system and the horizontal arm, so the force arm of the robot movement is very short, and there is basically no suction cup vibration. The suction cup clamp of the present invention has the functions of pitching, swinging and planar rotation. With the lifting and retracting movements of the tower body, horizontal arm and vertical arm, the posture of the suction cup can be adjusted to any angle, so that the suction cup clamp and the photovoltaic panel assembly can be perfectly aligned. Since the adjustment of the suction cup's subtle posture is close to the photovoltaic bracket, the movement adjustment does not rely on the support system and horizontal arm at the root, the force arm of the movement is very short, and there is basically no vibration of the suction cup. At the same time, the present invention firstly makes a rough adjustment to the position of the suction cup clamp through the vertical tower body, horizontal arm and vertical arm, and then adjusts the suction cup through the pitch cylinder, swing motor and rotation The motor fine-tunes the position of the suction cup to ensure the accuracy of construction; at the same time, the present invention is connected with a rotation angle monitoring sensor on the rotary drive device, a tower height monitoring sensor is arranged on the vertical tower body, a horizontal arm amplitude monitoring sensor is arranged on the horizontal arm, a vertical arm telescopic monitoring sensor is arranged on the vertical arm, and a suction cup rotation angle monitoring sensor is arranged on the rotating motor; a side swing angle and pitch angle monitoring sensor is arranged on the photovoltaic panel suction cup; the position of each driving component is detected by each sensor, and then in conjunction with the PLC control system, accurate grasping of the photovoltaic panel assembly is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0024] Figure 1 It is a structural schematic diagram of the automatic material taking device of the present invention;

[0025] Figure 2 It is a schematic diagram of the sensor installation position of the automatic material taking device of the present invention;

[0026] Figure 3 It is a schematic diagram of the control principle of the PLC control system;

[0027] Figure 4 : Sensor signal input schematic diagram;

[0028] Figure 5 :Control signal output control principle Figure 1 ;

[0029] Figure 6 :Control signal output control principle Figure 2 ;

[0030] Figure 7 : Schematic diagram of solenoid valve control switching;

[0031] In the figure: 1. GAS encoder; 2. WL300 pull-wire sensor; 3: WL300 pull-wire sensor; 4: WL200 pull-wire sensor; 5. GAS encoder; 6: laser sensor; 7: LCA-T sensor;

[0032] 11. Rotary hydraulic motor; 12. First-level tower body telescopic cylinder; 13. Second-level tower body telescopic cylinder; 14. First-level horizontal arm telescopic cylinder; 15. Second-level horizontal arm telescopic cylinder; 16. Vertical telescopic cylinder; 17. Suction cup pitch cylinder; 18. Suction cup swing motor; 19. Suction cup rotation motor; 20 tower body, 21 horizontal arm, 22 vertical arm, 23 connecting parts; 24 photovoltaic panel suction cup. DETAILED DESCRIPTION

[0033] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0034] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless otherwise explicitly stated in the present invention, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "include" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof;

[0035] For the convenience of description, if the words "up", "down", "left" and "right" appear in the present invention, they only indicate that they are consistent with the up, down, left and right directions of the drawings themselves, and do not limit the structure. They are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0036] Terminology explanation section: The terms "install", "connect", "connect", "fixed" and the like in the present invention should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral whole; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two elements, or an interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0037] As introduced in the background technology, there are deficiencies in the prior art. In order to solve the above technical problems, the present invention proposes a mechanical automatic material taking device and a control method for photovoltaic construction.

[0038] In a typical embodiment of the present invention, Figure 1 As shown, the mechanical automatic material-retrieving device for photovoltaic construction disclosed in this embodiment includes a vertical tower body 20, a rotary drive device is arranged at the bottom of the vertical tower body 20, and the rotation angle of the tower body 20 in the horizontal plane is controlled. A first telescopic oil cylinder is arranged on the vertical tower body 20, and the first telescopic oil cylinder performs the telescopic movement of the tower body 20 in the vertical direction; a horizontal arm 21 is connected to the top of the vertical tower body 20, a second telescopic oil cylinder is arranged on the horizontal arm 21, and a vertical arm 22 is arranged at the end of the horizontal arm 21, and the bottom of the vertical arm 22 is hinged to a connecting member 23, and the connecting member 23 is hinged to the photovoltaic panel suction cup 24, and a third telescopic oil cylinder and a suction cup pitch cylinder are installed on the vertical arm 22; the third telescopic oil cylinder performs the height adjustment of the vertical arm 22 Adjustment; the suction cup pitch cylinder 17 adjusts the pitch angle of the suction cup; a suction cup rotating motor 19 is arranged on the photovoltaic panel suction cup 24, and the suction cup rotating motor 19 controls the suction cup plane rotation angle; a suction cup swing motor 18 is arranged on the connecting piece 23, and the suction cup swing motor 18 controls the left and right swing angle of the suction cup; a rotation angle monitoring sensor is connected to the rotary drive device, a tower body 20 height monitoring sensor is arranged on the vertical tower body 20, a horizontal arm amplitude monitoring sensor is arranged on the horizontal arm 21, a vertical arm telescopic monitoring sensor is arranged on the vertical arm 22, and a suction cup rotation angle monitoring sensor is arranged on the suction cup rotating motor 19; a side swing angle and pitch angle monitoring sensor are arranged on the photovoltaic panel suction cup 24.

[0039] As a further technical solution, the first telescopic cylinder includes at least two stages of telescopic cylinders, and the first-stage telescopic cylinder drives a tower body 20. The tower body 20 disclosed in this embodiment includes three tower bodies 20. The first tower body 20 is fixed, and the second tower body 20 is telescoped up and down under the action of the telescopic cylinder 12 of the first tower body 20; the third tower body 20 is telescoped up and down in the second tower body 20 under the action of the telescopic cylinder 13 of the second tower body 20.

[0040] As a further technical solution, the second telescopic oil cylinder includes at least two telescopic oil cylinders, and the first telescopic oil cylinder drives a horizontal arm. The horizontal arm disclosed in this embodiment includes three sections, the first horizontal arm is fixed, the second horizontal arm is telescopic in the horizontal direction under the action of the first horizontal arm telescopic oil cylinder 14; the third horizontal arm is telescopic in the horizontal direction within the second horizontal arm under the action of the second horizontal arm telescopic oil cylinder 15.

[0041] As a further technical solution, the third telescopic cylinder includes a first-level vertical telescopic cylinder 16. The vertical arm disclosed in this embodiment includes two sections. The first vertical arm is fixed, and the second vertical arm is telescopic in the vertical direction under the action of the first-level vertical telescopic cylinder 16.

[0042] As a further technical solution, the above-mentioned rotary drive device adopts an existing rotary hydraulic motor 11 to control the rotation angle of the tower body 20 .

[0043] As a further technical solution, the rotation angle monitoring sensor adopts a GAS encoder 1. The GAS encoder 1 installed on the rotary hydraulic motor 11 is used to detect the rotation angle value of the tower body 20 in real time, and the GAS encoder 5 installed on the suction cup rotation motor 19 is used to detect the suction cup rotation angle value in real time.

[0044] As a further technical solution, the tower body 20 height monitoring sensor adopts a WL300 wire sensor 2 for real-time detection of the tower body 20 height value.

[0045] As a further technical solution, the horizontal arm amplitude monitoring sensor adopts the WL300 wire sensor 3, which is used to detect the horizontal arm amplitude value in real time.

[0046] As a further technical solution, the vertical arm telescopic monitoring sensor adopts a WL200 wire sensor 4 for real-time detection of the vertical arm telescopic value.

[0047] As a further technical solution, a laser sensor 6 is also provided on the photovoltaic panel suction cup 24 for detecting the distance between the suction cup and the photovoltaic panel in real time.

[0048] As a further technical solution, the roll angle and pitch angle monitoring sensor adopts LCA-T sensor 7.

[0049] As a further technical solution, the rotation angle monitoring sensor, tower height monitoring sensor, horizontal arm amplitude monitoring sensor, vertical arm telescopic monitoring sensor, laser sensor 6, and side swing angle and pitch angle monitoring sensors are all connected to a PLC controller, and the PLC controller controls the slewing drive device, the first telescopic cylinder, the second telescopic cylinder, the third telescopic cylinder, the pitch cylinder, the suction cup swing motor 18, and the suction cup rotation motor 19.

[0050] The method of controlling the mechanical automatic material taking device for photovoltaic construction using the PLC controller is as follows:

[0051] Step 1, determine the photovoltaic panel assembly placement position coordinates (these coordinates are determined in advance and can be written into the PLC controller in advance);

[0052] Step 2, detecting the current posture and position of the mechanical automatic material taking device according to the rotation angle monitoring sensor, tower height monitoring sensor, horizontal arm amplitude monitoring sensor, vertical arm telescopic monitoring sensor, laser sensor 6, and side swing angle and pitch angle monitoring sensors;

[0053] In step 3, the PLC controller compares the data collected in step 2 with the coordinates of step 1, and then drives the rotary drive device, the first telescopic cylinder, the second telescopic cylinder, the third telescopic cylinder, the pitch cylinder, the suction cup swing motor 18, and the suction cup rotation motor 19 to perform corresponding actions according to the difference to achieve the grasping of the photovoltaic panel assembly.

[0054] More specifically, the PLC controller communicates wirelessly with a wireless remote controller, and also includes a signal amplifier and an electro-hydraulic proportional valve; the remote controller is used to send command signals and control the photovoltaic construction machinery to complete various actions through manual operation; the PLC controller receives input information from various sensors, processes the logic program, and then outputs a control signal; the signal amplifier is used to amplify the 4-20mA control signal output by the PLC and convert it into a drive control signal for the electro-hydraulic proportional valve; the electro-hydraulic proportional valve is an actuator for controlling the flow rate of the hydraulic cylinder; the hydraulic cylinder drives each mechanism to operate and realize the automatic material picking function; the wire encoder, rotary encoder, azimuth sensor and other components are used to detect the current position of the suction cup and provide feedback signals to the PLC system.

[0055] In this new type of application, the PLC can automatically identify the current position of the suction cup. When the "automatic material picking" control signal is sent through the remote control, the PLC outputs the control signal after internal logic operation processing. After amplification processing, each actuator is driven to operate, guiding the suction cup to automatically return to the material storage position, and automatically stop after the photovoltaic panel is sucked, preparing for the next work cycle.

[0056] This equipment uses a remote control to operate each action mechanism of the equipment. When using the automatic material collection function, the remote control gives the "automatic material collection" signal command, and the control circuit automatically switches the line, and the equipment performs automatic material collection control. To realize the self-positioning material collection function, it is necessary to first determine the material placement position coordinates (we call it the zero point coordinates) and then determine the tower body rotation angle, tower body height, horizontal arm amplitude, vertical arm position, suction cup pitch angle, rotation angle, side swing angle and other parameters.

[0057] When the suction cup is in any other position, some or all of the above parameters will change in value. Through the PLC logic processing function, the current value of each parameter is compared with the zero point coordinate value to obtain the difference between the current position and the zero point coordinate. When the automatic material picking instruction is issued, the PLC system will automatically determine the direction of the coordinate difference reduction and continuously output the control signal of each mechanism to control the operation of each mechanism until it returns to the coordinate zero point position and stops.

[0058] Finally, it should be noted that relational terms such as first and second are merely used to distinguish one entity or operation from another entity or operation, but do not necessarily require or imply any actual relationship or order between these entities or operations.

[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A mechanical automatic material taking device for photovoltaic construction, characterized in that: It comprises a vertical tower body, a slewing drive device is arranged at the bottom of the vertical tower body, and a first telescopic oil cylinder is arranged on the vertical tower body; a horizontal arm is connected to the top of the vertical tower body, a second telescopic oil cylinder is arranged on the horizontal arm, a vertical arm is arranged at the end of the horizontal arm, the bottom of the vertical arm is hinged with a connecting piece, the connecting piece is hinged with the photovoltaic panel suction cup, and a third telescopic oil cylinder and a pitching oil cylinder are installed on the vertical arm; a rotating motor is arranged on the photovoltaic panel suction cup; a swinging motor is arranged on the connecting piece; a rotation angle monitoring sensor is connected to the slewing drive device, a tower body height monitoring sensor is arranged on the vertical tower body, a horizontal arm amplitude monitoring sensor is arranged on the horizontal arm, a vertical arm telescopic monitoring sensor is arranged on the vertical arm, and a suction cup rotation angle monitoring sensor is arranged on the slewing motor; a side swing angle and pitch angle monitoring sensor are arranged on the photovoltaic panel suction cup.

2. The mechanical automatic material taking device for photovoltaic construction as claimed in claim 1, characterized in that: The first telescopic oil cylinder comprises at least two stages of telescopic oil cylinders, and a first stage of telescopic oil cylinder drives a section of the tower body.

3. The mechanical automatic material taking device for photovoltaic construction as claimed in claim 1, characterized in that: The second telescopic oil cylinder comprises at least two stages of telescopic oil cylinders, and a first stage of the telescopic oil cylinder drives a horizontal arm.

4. The mechanical automatic material taking device for photovoltaic construction as claimed in claim 1, characterized in that: The third telescopic oil cylinder comprises a first-stage telescopic oil cylinder, and the first-stage telescopic oil cylinder drives a vertical arm.

5. The mechanical automatic material taking device for photovoltaic construction as claimed in claim 1, characterized in that: The rotation angle monitoring sensor adopts an encoder.

6. The mechanical automatic material taking device for photovoltaic construction as claimed in claim 1, characterized in that: The tower height monitoring sensor, the horizontal arm amplitude monitoring sensor, and the vertical arm telescopic monitoring sensor all adopt pull-wire sensors.

7. The mechanical automatic material taking device for photovoltaic construction as claimed in claim 1, characterized in that: A laser sensor is also provided on the photovoltaic panel suction cup for detecting the distance between the suction cup and the photovoltaic panel in real time.

8. The mechanical automatic material taking device for photovoltaic construction as claimed in claim 1, characterized in that: The roll angle and pitch angle monitoring sensors use LCA-T sensors.

9. The mechanical automatic material taking device for photovoltaic construction as claimed in claim 1, characterized in that: The rotation angle monitoring sensor, tower height monitoring sensor, horizontal arm amplitude monitoring sensor, vertical arm telescopic monitoring sensor, laser sensor, and side swing angle and pitch angle monitoring sensors are all connected to the PLC controller, and the PLC controller controls the slewing drive device, the first telescopic oil cylinder, the second telescopic oil cylinder, the third telescopic oil cylinder, the pitch oil cylinder, the swing motor, and the rotating motor.

10. The control method of the mechanical automatic material taking device for photovoltaic construction according to claim 9, characterized in that: as follows: Step 1, obtaining the location coordinates of the photovoltaic panel assembly; Step 2, detecting the current posture and position of the mechanical automatic material taking device according to the rotation angle monitoring sensor, tower height monitoring sensor, horizontal arm amplitude monitoring sensor, vertical arm telescopic monitoring sensor, laser sensor, and side swing angle and pitch angle monitoring sensor; Step 3, the PLC controller compares the data collected in step 2 with the coordinates of step 1, and then drives the rotary drive device, the first telescopic cylinder, the second telescopic cylinder, the third telescopic cylinder, the pitch cylinder, the swing motor, and the rotating motor to perform corresponding actions according to the difference to achieve the grabbing of the photovoltaic panel assembly.

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