Constant tension control device and method for macroalgae culture rope under variable load

Abstract

The invention provides a constant tension control device and method for a macroalgae culture rope under variable loads. The constant tension control device comprises a bottom plate, the bottom plate is provided with a first rope pulling machine used for maintaining tensioning of a breeding rope in the macroalgae harvesting process, a second rope pulling machine used for simulating the load force borne by the first rope pulling machine when the first rope pulling machine drags the breeding rope in the macroalgae harvesting process, and a rope releasing machine located between the first rope pulling machine and the second rope pulling machine and used for winding the breeding rope. A driving motor in the first rope pulling machine and a driving motor in the second rope pulling machine are connected with a PLC (Programmable Logic Controller); the land-based constant-tension experiment bench system has the beneficial effects that the land-based constant-tension experiment bench system is designed, the tension of the culture rope with macroalgae is kept relatively stable in a variable load state, or dragging is automatically paused when dragging is stuck, the condition that the culture rope is cut off by a cutter due to heaving caused by sudden disappearance of stress or is snapped due to excessive stress is avoided, and the service life of the culture rope is prolonged. And a reference basis is provided for marine practical application, and the large algae culture rope is ensured to be safe and not to be damaged in the dragging process.

Description

Technical Field

[0001] The present invention relates to the technical field of fishery equipment, and particularly to a constant tension control device and method for a large algae cultivation rope under variable loads. Background Art

[0002] Currently, when dragging the kelp seeding ropes onto the ship, a continuous kelp shearing device is used to separate the ropes from the kelp. The existing continuous kelp shearing device mainly consists of a front guiding roller, a lifting and conveying device, a shearing knife, a seedling rope traction device, a storage device for the ropes after harvesting, a conveying device for the kelp after cutting, and a kelp storage device, etc. During the dragging process, the shearing knife is used to automatically cut off the roots of the kelp attached to the ropes. In this process, it is necessary to ensure that the ropes attached with kelp are always kept taut and continuously dragged. However, during the continuous shearing and harvesting of kelp, affected by multiple factors such as ocean winds, waves, currents, and raft frames, the dragging speed and force of the kelp seedling ropes are likely to change greatly. If the tension of the seedling ropes is too large, it is easy to cause the ropes to break due to excessive stress or undergo plastic deformation; if the tension of the seedling ropes suddenly disappears, the catenary angle of the kelp seedling ropes near the shearing knife will suddenly increase, and it is extremely easy to be cut by the knife or jam the knife. Both of the above situations will lead to the interruption of harvesting and affect the service life of the cultivation ropes. Therefore, during the kelp harvesting process, it is necessary to keep the traveling speed of the kelp seedling ropes stable within a certain range and keep the ropes always taut to prevent the ropes from being damaged. Summary of the Invention

[0003] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a constant tension control device and method for a large algae cultivation rope under variable loads, which is used to solve the problems in the prior art that if the tension of the seedling ropes is too large, it is easy to cause the ropes to break due to excessive stress or undergo plastic deformation, and if the tension of the seedling ropes suddenly disappears, the catenary angle of the kelp seedling ropes near the shearing knife will suddenly increase, and it is extremely easy to be cut by the knife or jam the knife.

[0004] To achieve the above purpose and other related purposes, the present invention provides the following technical solutions:

[0005] A constant tension control device for a large algae cultivation rope under variable loads includes a bottom plate. On the bottom plate, there is a first rope pulling machine for maintaining the tension of the cultivation rope during the harvesting process of large algae, a second rope pulling machine for simulating the load force received by the first rope pulling machine when dragging the cultivation rope during the harvesting process of large algae, and a rope releasing machine located between the first rope pulling machine and the second rope pulling machine and used for winding the cultivation rope. There is also a supporting pulley slidably connected to the cultivation rope between the first rope pulling machine and the second rope pulling machine. At the top of the supporting pulley, there is a shearing knife for cutting off the large algae attached to the cultivation rope. Moreover, the drive motors of the first rope pulling machine and the second rope pulling machine are both connected to a PLC controller.

[0006] In one embodiment of the present invention, the first rope pulling machine includes a first base frame, a variable frequency motor, a first torque sensor and a first winch installed in sequence on the first base frame, the output shaft of the variable frequency motor is connected to the first output shaft of the first torque sensor through a first coupling, the second output shaft of the first torque sensor is connected to a first rotating shaft through a second coupling, the end of the first rotating shaft away from the first torque sensor is inserted into the first winch, and the first winch is provided with a first traction disc.

[0007] In one embodiment of the present invention, the second rope pulling machine includes a second base frame, a servo motor, a second torque sensor and a second winch installed in sequence on the second base frame, a second rotating shaft is connected to the output shaft of the servo motor, the end of the second rotating shaft away from the servo motor is connected to the first output shaft of the second torque sensor through a third coupling, the second output shaft of the second torque sensor is connected to a third rotating shaft through a fourth coupling, the end of the third rotating shaft away from the second torque sensor is inserted into the second winch, and a second traction disk is provided on the second winch.

[0008] In one embodiment of the present invention, an electromagnetic clutch located on the side of the third coupling is provided on the end of the second rotating shaft close to the servo motor, and a pneumatic brake for providing damping torque is provided between the electromagnetic clutch and the third coupling. The pneumatic brake includes a pneumatic component installed on the second base frame and a brake disc mounted on the second rotating shaft.

[0009] A method for controlling the constant tension of a large algae cultivation rope under variable load based on the large algae cultivation rope constant tension control device under variable load is applied to a second rope pulling machine, and comprises the following steps: the second rope pulling machine is used to simulate the random change of force value during the large algae harvesting process, the large algae cultivation rope is subjected to the pressure of the traction disks on both sides in the gap of the second rope pulling machine, the large algae cultivation rope and the second traction disk on the second rope pulling machine have no relative sliding, the electromagnetic clutch is in a released state at this time, and the damping torque of the second rope pulling machine is only provided by the pneumatic brake.

[0010] In one embodiment of the present invention, the variable load curve is pre-set in the PLC controller or the required load force is manually set on the touch screen, and the corresponding pressure value is obtained according to the relationship between the theoretical load force and the pressure, and the converted pressure value is output through the model quantity to realize the proportional control of the pneumatic brake, thereby achieving the control of the output torque of the second rope pulling machine; wherein, when the set load force increases, the pressure increases, the pneumatic brake tightens, and the output force of the second winch increases; when the set load force decreases, the pneumatic brake relaxes, and the output force of the second winch decreases, thereby realizing the variable load simulation in the process of harvesting kelp.

[0011] In an embodiment of the present invention, obtaining the corresponding pressure value according to the relationship between the theoretical load force and the pressure includes: determining the relationship between the theoretical load force and the pressure according to the following formula: where P is the air pressure in the air cylinder of the pneumatic component; F 负载 is the load force; r2 is the radius of the second traction disc; r2' is the distance from the center of the culture rope to the arc of the second traction disc, and the theoretical calculation is approximately the radius of the culture rope; R is the radius of the air cylinder in the pneumatic component; u is the friction coefficient; S is the domain of the brake pad on the brake disc, S = S1 + S2 + S3; x and y take the center of the brake disc as the origin, the horizontal direction is the X-axis, and the vertical direction is the Y-axis.

[0012] In an embodiment of the present invention, when applied to the first rope pulling machine, it includes the following steps: the first rope pulling machine is used to maintain the tension of the culture rope during the actual harvesting process. When the first rope pulling machine drags the culture rope, in order to overcome the damping torque of the second rope pulling machine, the first rope pulling machine rotates. At this time, when the first rope pulling machine rotates, the first traction disc opens, and the large algae culture rope is sent out, so as to realize the dragging of the culture rope with a dragging force; wherein, the first rope pulling machine sets its tension force as a fixed value according to the required torque and the size of the winch.

[0013] In an embodiment of the present invention, the relationship between it and the dragging speed is dynamically adjusted through the PID control algorithm in the PLC controller. When the dragging force of the first rope pulling machine decreases, the speed increases; when the dragging force increases, the speed decreases, so as to keep the power relatively stable; and when the load force obtained by converting the value of the first torque sensor in the first rope pulling machine is less than the set value, through the adjustment of the PID control algorithm, the output torque of the frequency conversion motor is quickly increased; when the load force obtained by converting the value of the first torque sensor in the first rope pulling machine is greater than the set value, through the adjustment of the PID control algorithm, the output torque of the frequency conversion motor is reduced, so as to realize the constant tension control during the process of harvesting large algae.

[0014] In an embodiment of the present invention, dynamically adjusting the relationship between it and the dragging speed through the PID control algorithm in the PLC controller includes: the logic control program in the PLC controller adopts the PID control algorithm, through the proportional coefficient (K p ), integral coefficient (K i ) and differential coefficient (K d) The functional relationship of () is used to operate on the input deviation value, and the operation result is used to control the output; when a relatively large deviation step occurs in the feedback signal, the proportional link and the differential link work simultaneously to suppress the change in the feedback input brought about by this deviation step, and at the same time, an integral link is considered to be added to eliminate the residual error; the deviation value e(t) between the set value r(t) and the measured load force f(t) is used as the input signal, and its expression formula is as follows: e(t) = r(t) - f(t); PID control is to linearly combine the proportional, integral, and differential of e(t) to form a control quantity for control, and its output signal is: After Laplace transform, the transfer function of the PID controller is:

[0015] As described above, a constant tension control device and method for large algae cultivation ropes under variable loads according to the present invention have the following beneficial effects: The present invention obtains the corresponding pressure value according to the relationship between the theoretical load force and the pressure by presetting a variable load curve in the PLC controller or manually setting the required load force on the touch screen, and realizes the proportional control setting of the pneumatic brake in the second rope pulling machine by outputting the converted pressure value through the model quantity to set the required load force, so as to be able to simulate the random change of the force value during the large algae harvesting process. The tension of the first rope pulling machine is set as a fixed value. When the first rope pulling machine drags the cultivation ropes with different load forces, the relationship between it and the dragging speed is dynamically adjusted through the PID control algorithm in the PLC controller to realize the constant tension control during the large algae harvesting process, so as to solve the problems that the excessive tension of the cultivation rope is likely to cause the rope to break due to excessive force or plastic deformation, and the sudden disappearance of the tension of the cultivation rope will cause the catenary angle of the kelp seedling rope near the cutting knife to increase suddenly, which is extremely easy to be cut by the tool or jam the tool. During the large algae harvesting process, the traveling speed of the large algae cultivation rope is kept stable within the interval and the large algae cultivation rope is always kept in a tensioned state to prevent the large algae cultivation rope from being damaged. Brief Description of the Drawings

[0016] Figure 1 is a three-dimensional schematic diagram of the constant tension control device for large algae cultivation ropes under variable loads in the first embodiment of the present invention;

[0017] Figure 2 is a front view schematic diagram of the constant tension control device for large algae cultivation ropes under variable loads in the first embodiment of the present invention;

[0018] Figure 3 is a top view schematic diagram of the constant tension control device for large algae cultivation ropes under variable loads in the first embodiment of the present invention;

[0019] Figure 4It is a three-dimensional schematic diagram of the first rope pulling machine in the constant tension control device for large algae cultivation ropes under variable loads in the first embodiment of the present invention;

[0020] Figure 5 It is a cross-sectional schematic diagram of the first rope pulling machine in the constant tension control device for large algae cultivation ropes under variable loads in the first embodiment of the present invention;

[0021] Figure 6 It is a three-dimensional schematic diagram of the second rope pulling machine in the constant tension control device for large algae cultivation ropes under variable loads in the first embodiment of the present invention;

[0022] Figure 7 It is a cross-sectional schematic diagram of the second rope pulling machine in the constant tension control device for large algae cultivation ropes under variable loads in the first embodiment of the present invention;

[0023] Figure 8 It is a flow schematic diagram of the constant tension control method for large algae cultivation ropes under variable loads in the second embodiment of the present invention;

[0024] Figure 9 It is a schematic diagram of the integration interval of the brake disc in the constant tension control method for large algae cultivation ropes under variable loads in the second embodiment of the present invention;

[0025] Figure 10 It is a schematic diagram of the relationship between the theoretical torque and the pressure in the constant tension control method for large algae cultivation ropes under variable loads in the second embodiment of the present invention;

[0026] Figure 11 It is a schematic diagram of the relationship between the theoretical load force and the pressure in the constant tension control method for large algae cultivation ropes under variable loads in the second embodiment of the present invention;

[0027] Figure 12 It is a schematic diagram of the electrical control principle of the second rope pulling machine in the constant tension control method for large algae cultivation ropes under variable loads in the second embodiment of the present invention;

[0028] Figure 13 It is a constant tension logic control block diagram of the first rope pulling machine in the constant tension control method for large algae cultivation ropes under variable loads in the second embodiment of the present invention;

[0029] Figure 14 It is a principle block diagram of the constant tension PID control in the constant tension control method for large algae cultivation ropes under variable loads in the second embodiment of the present invention;

[0030] Figure 15 It is a principle block diagram of the joint debugging electrical control system of the first rope pulling machine and the second rope pulling machine in the constant tension control method for large algae cultivation ropes under variable loads in the second embodiment of the present invention.

[0031] Description of component numbers

[0032] 1. Bottom plate; 2. First rope pulling machine; 201. First chassis; 202. Variable-frequency motor; 203. First torque sensor; 204. First winch; 205. First coupling; 206. Second coupling; 207. First bearing seat; 208. First rotating shaft; 3. Support pulley; 4. Stripping cutter; 5. Cultivation rope; 6. Second rope pulling machine; 601. Second chassis; 602. Servo motor; 603. Second torque sensor; 604. Second winch; 605. Electromagnetic clutch; 606. Pneumatic brake; 607. Second bearing seat; 608. Third coupling; 609. Fourth coupling; 610. Third bearing seat; 611. Second rotating shaft; 612. Third rotating shaft; 7. Rope releasing machine; 8. First traction disc; 9. Second traction disc; 10. Pneumatic component; 11. Brake disc. Specific embodiments

[0033] The following specific examples illustrate the embodiments of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0034] The first embodiment of the present invention relates to a constant tension control device for large algae cultivation ropes under variable loads, that is, a land-based constant tension test bench system. Please refer to Figures 1 to 3 , which includes a bottom plate 1. On the bottom plate 1, there is a first rope pulling machine 2 for maintaining the tension of the cultivation rope 5 during the harvesting process of large algae, a second rope pulling machine 6 for simulating the load force received by the first rope pulling machine 2 when dragging the cultivation rope 5 during the harvesting process of large algae, and a rope releasing machine 7 located between the first rope pulling machine 2 and the second rope pulling machine 6 and used for winding the cultivation rope 5. There is also a support pulley 3 slidably connected to the large algae cultivation rope 5 between the first rope pulling machine 2 and the second rope pulling machine 6. At the top of the support pulley 3, there is a stripping cutter 4 for cutting off the large algae attached to the cultivation rope 5. And the drive motors in both the first rope pulling machine 2 and the second rope pulling machine 6 are connected to the PLC controller, that is, the variable-frequency motor 202 and the servo motor 602 in the following text; it should be noted that the present invention also includes measuring devices such as high-speed cameras; also, the winch structures in the first rope pulling machine 2 and the second rope pulling machine 6 can refer to the patent (2023107894042), and the specific structure of the rope releasing machine 7 can refer to the patent (2022100476101).

[0035] As Figure 4 and Figure 5As shown in the figure, the first rope pulling machine 2 includes a first chassis 201, a variable frequency motor 202, a first torque sensor 203, and a first winch 204 that are sequentially installed on the first chassis 201. An encoder is provided in the variable frequency motor 202. The output shaft of the variable frequency motor 202 is connected to the first output shaft of the first torque sensor 203 through a first coupling 205. A first rotating shaft 208 is connected to the second output shaft of the first torque sensor 203 through a second coupling 206. The end of the first rotating shaft 208 away from the first torque sensor 203 is inserted into the first winch 204. A first traction disc 8 is provided on the first winch 204. A first bearing seat 207 is further provided on the first chassis 201 between the second coupling 206 and the first winch 204. The first rotating shaft 208 is inserted into the first bearing seat 207.

[0036] As Figure 6 and Figure 7 As shown in the figure, the second rope pulling machine 6 includes a second chassis 601, a servo motor 602, a second torque sensor 603, and a second winch 604 that are sequentially installed on the second chassis 601. A second rotating shaft 611 is connected to the output shaft of the servo motor 602. The end of the second rotating shaft 611 away from the servo motor 602 is connected to the first output shaft of the second torque sensor 603 through a third coupling 608. A third rotating shaft 612 is connected to the second output shaft of the second torque sensor 603 through a fourth coupling 609. The end of the third rotating shaft 612 away from the second torque sensor 603 is inserted into the second winch 604. A second traction disc 9 is provided on the second winch 604. It should be noted that a pressing block is provided on the traction disc, and the pressing block plays a role in pressing the aquaculture rope 5. For details, please refer to the patent (2023107894042);

[0037] An electromagnetic clutch 605 is provided on the end of the second rotating shaft 611 close to the servo motor 602 on the side of the third coupling 608. The electromagnetic clutch 605 is installed on the second rotating shaft 611 through a clutch connection flange. An air brake 606 for providing damping torque is provided between the electromagnetic clutch 605 and the third coupling 608. The air brake 606 includes a pneumatic component 10 installed on the second chassis 601 and a brake disc 11 sleeved on the second rotating shaft 611. A brake pad is provided between the pneumatic component 10 and the brake disc 11. A second bearing seat 607 is further provided on the second chassis 601 between the air brake 606 and the third coupling 608. The second rotating shaft 611 is inserted into the first bearing seat 607. A third bearing seat 610 is further provided on the second chassis 601 between the fourth coupling 609 and the second winch 604. The third rotating shaft 612 is inserted into the third bearing seat 610.

[0038] Specifically, the purpose of the present invention is to provide a large algae culture rope constant tension control device under variable load, which can prevent the culture rope from being cut or pulled off by a cutter due to the change of force during offshore operation, and can accurately measure the swaying speed and angle of the kelp rope under different stress states during the movement of the rope, so as to provide a reference basis for practical application at sea and ensure that the kelp seedling rope is safe and not damaged during the dragging process; the working principle of the present invention is: the culture rope 5 is sent from the right side by the rope release machine 7, and after passing through the second rope pulling machine 6, the culture rope 5 has a certain tension, and the tension source is provided by the second rope pulling machine 6, and the second rope pulling machine 6 is used to pull the rope between the support pulley 3 and the second rope pulling machine 6. The rope pulling machine 6 is set to be 4-5 meters long in the middle (this is because the length of kelp is about 4-5 meters. When cutting, the kelp and the breeding rope 5 need to be in a relatively vertical state to prevent the rotating knife from cutting the shoulder of the kelp and affecting its quality. A kelp is hung on the breeding rope 5 every 5 cm. A single kelp weighs about 2.5 kg. Therefore, the load on this 5-6 meter rope is about 200-250 kg, and it is in a falling arc under stress). The first rope pulling machine 2 on the left is driven by a variable frequency motor 202. A torque sensor is installed between the variable frequency motor 202 and the first rope pulling machine 2 to facilitate the measurement of dynamic torque when pulling the rope. For details, please refer to Figures 1 to 3 .

[0039] The second embodiment of the present invention relates to a method for controlling the constant tension of a macroalgae cultivation rope under variable load, the process is as follows: Figure 8 As shown, the details are as follows:

[0040] Step 101, the second rope pulling machine 6 is used to simulate the random change of force value during the large algae harvesting process. The large algae cultivation rope 5 is subjected to the pressure of the traction discs on both sides in the gap of the second rope pulling machine 6. There is no relative sliding between the large algae cultivation rope 5 and the second traction disc 9 on the second rope pulling machine 6. At this time, the electromagnetic clutch 605 is in a released state, and the damping torque of the second rope pulling machine 6 is only provided by the pneumatic brake 606.

[0041] Specifically, the variable load curve preset in the PLC controller or the required load force manually set on the touch screen is used according to the Figure 11 The conversion relationship between the theoretical load force and the pressure is used to obtain the pressure value, and the converted pressure value is output through the model quantity to realize the proportional control of the pneumatic brake 606, thereby achieving the control of the output torque of the second rope pulling machine 6. When the set load force increases, the pressure increases, the pneumatic brake 606 tightens, and the output force of the second winch 604 increases; when the set load force decreases, the pneumatic brake 606 relaxes, and the output force of the second winch 604 decreases, realizing the variable load simulation in the process of harvesting kelp. The control method is as follows: Figure 12 shown.

[0042] More specifically, 1. The process of calculating the relationship between the theoretical load capacity and pressure is as follows: The second towing rope machine 6 (which plays a load-bearing role) simulates and provides the load during kelp harvesting. The load is provided by the frictional force between the brake disc 11 and the pneumatic component 10. The theoretical diagram is as shown in Figure 9 and its calculation formula is:

[0043] F f = 4πR 2 Pμ (1);

[0044] Among them, F f is the frictional force exerted by the pneumatic component 10 on the brake disc 11, in N; R is the radius of the pneumatic cylinder in the pneumatic component 10, in m (the radius of the pneumatic cylinder in the pneumatic component 10 is 50 mm, that is, 0.05 m); P is the air pressure in the pneumatic cylinder of the pneumatic component 10, in Mpa (the normal maximum air pressure is 0.6 Mpa, and it can reach 0.7 Mpa in experiments); μ is the friction coefficient (0.3 - 0.4, taking 0.3);

[0045]

[0046] Among them, T f is the load torque provided by the brake disc 11, in N·m; F f ' is the frictional force per unit area of the brake pad, in N, that is S A is the contact area between the brake pad and the brake disc 11, in m 2 (about 3775.10 mm2, that is, 0.0037751 m2); S is the domain of the brake pad on the brake disc 11, S = S1 + S2 + S3, and x1, x2, y1, y2, y3 are 0.039, -0.039, -0.078, -0.09325, -0.10875 respectively;

[0047] That is, T f = 7.5130×10 -4 P. According to Figure 10 it can be seen that by controlling the air pressure to control the torque of the brake disc 11, and then through the torque and the radius of the traction disc, the theoretical load capacity of the culture rope 5 can be obtained. The formula is:

[0048]

[0049] Among them, F_load is the load generated by the rope during the simulated harvesting process, in N; r2 is the radius of the second traction disc 9, in m (about 110 mm, that is, 0.11 m); r2' is the distance from the center of the culture rope 5 to the arc of the second traction disc 9, and the theoretical calculation is approximately the radius of the culture rope 5, in m (in the actual operation process, the culture rope 5 may not be attached to the traction disc), that is Assume that r2 is approximately 7 - 9 mm, that is, 0.007 - 0.009 m. At this time, F 负载 ≈6.4214×10 -3 P to 6.3134×10 -3 P. Based on this, we get Figure 11 , according to Figure 11 , from the perspective of , the error brought by r2' is very small, and the minimum of 0.7 Mpa can reach 450.96 kg, which can reach the load at the time of harvesting;

[0050] By reverse - deducing according to formulas (1), (2), and (3), the relationship between the air pressure P and the traction force F can be obtained:

[0051]

[0052] Among them, according to formula (4), for loads of 50 kg, 100 kg, and 200 kg, the air pressures required for the pneumatic brake 606 are approximately 0.0763 - 0.0776 Mpa, 0.1526 - 0.1552 Mpa, and 0.3052 - 0.3104 Mpa respectively;

[0053] 2. The process of calculating the relationship between speed and rotational speed is as follows: The torque and rotational speed on the traction disc can be obtained according to the torque meter, and the theoretical speed formula of the rope is obtained, that is:

[0054] v = n(r + r') (5)

[0055] Among them, v is the speed of the aquaculture rope 5, m / s; n is the rotational speed of the shaft, rpm; r is the radius of the traction disc, m; r' is the distance between the arc of the traction disc and the center of the aquaculture rope 5, m;

[0056] 3. The process of calculating the relationship between the load and torque of the first rope - pulling machine 2 is as follows: The relationship formula between the load and torque of the first rope - pulling machine 2 is the same as formula (3), that is:

[0057] T1 = F 负载 (r1 + r1') (6)

[0058] Among them, T1 is the torque of the first torque sensor 203, N·m; r1 is the radius of the traction disc of the first rope - pulling machine 2, m; r1' is the distance between the arc of the first traction disc 8 and the center of the aquaculture rope 5, m.

[0059] Step 102, the first rope - pulling machine 2 is used to keep the aquaculture rope 5 taut during the actual harvesting process. When the first rope - pulling machine 2 drags the aquaculture rope 5, in order to overcome the damping torque of the second rope - pulling machine 6, the first rope - pulling machine 2 rotates. At this time, when the first rope - pulling machine 2 rotates, the first traction disc 8 opens, and the large - scale algal aquaculture rope 5 is sent out, so as to realize the dragging of the aquaculture rope 5 with a dragging force. Among them, the first rope - pulling machine 2 sets its tension force as a fixed value according to the required torque and the size of the winch.

[0060] Specifically, the first rope pulling machine 2 is used to keep the aquaculture rope 5 taut during the actual harvesting process, prevent the aquaculture rope 5 from sagging too much and being damaged by the harvesting tool, and prevent the aquaculture rope 5 from being too tight and causing the rope to break or the vehicle to stop due to overload; the cable traction device adopted eliminates the torque change caused by cable laying, and sets its tension force as a fixed value according to the required torque and winch size;

[0061] Currently, the tensile force range of the aquaculture rope 5 is ≤3000N. Therefore, the limit tensile force set for the first rope pulling machine 2 is 3000N. When the damping required pulling force of the second rope pulling machine 6 is greater than 3000N, the first rope pulling machine 2 maintains the set maximum tension force and works. At this time, an error will also be reported, indicating abnormal work and requiring manual intervention; when the damping required pulling force of the second rope pulling machine 6 is less than 3000N, under the detection of the torque sensor of the first rope pulling machine 2, the relationship between it and the pulling speed is dynamically adjusted through the PLC controller. The speed setting of the present invention is ≤12m / min. When the pulling force decreases, the speed increases; when the pulling force increases, the speed decreases to keep the power relatively stable; at the same time, the torque sensor detects and outputs torque and rotational speed in real time, records the rope pulling force and pulling speed, and the high-speed camera records the sagging angle of the rope under different pulling forces.

[0062] More specifically, constant torque means keeping the motor driving torque constant, that is, it is required to increase the PWM duty cycle to 100% at the fastest speed and keep it constant, that is, constant maximum torque control; the load characteristics are as follows: (1) when the load increases, the rotational speed will decrease and the current will increase; (2) when the load decreases, the rotational speed will increase and the current will decrease;

[0063] When the load force obtained by converting the value of the torque sensor in the first rope pulling machine 2 is less than the set value, the output torque of the variable-frequency motor 202 is quickly increased through the adjustment of the PID control algorithm; when the load force obtained by converting the value of the torque sensor in the first rope pulling machine 2 is greater than the set value, the output torque of the variable-frequency motor 202 is reduced through the adjustment of the PID control algorithm to achieve constant tension control during the process of harvesting large algae. For details, please refer to Figure 13 ;

[0064] The logic control program in the PLC controller adopts the PID algorithm, and operates on the input deviation value through the functional relationship of the proportional coefficient (K p ), integral coefficient (K i ), and differential coefficient (K d ), and uses the operation result to control the output; when there is a relatively large deviation step in the feedback signal, the proportional link and the differential link work simultaneously to suppress the change in the feedback input caused by this deviation step; at the same time, an integral link is considered to eliminate the residual error. The control principle block diagram is as Figure 14As shown in the figure. The deviation value e(t) between the set value r(t) and the measured load force f(t) is used as the input signal, and its expression formula is as follows: e(t) = r(t) - f(t); PID control forms the control quantity through linear combination of the proportional, integral, and differential of e(t) for control, and its output signal is: After Laplace transform, the transfer function of the PID controller is:

[0065] Simulation of instability: The pneumatic brake 606 has no pressure at all, the second drag rope machine 6 loses damping, the first drag rope machine 2 is detected by the torque sensor. The system drag force is too low and the instantaneous drag speed is too high. The system automatically starts the protection measures. The electromagnetic clutch 605 engages, and the servo motor 602 rotates in reverse to provide a certain torque to the second drag rope machine 6. At the same time, the speed of the variable-frequency motor 202 of the first drag rope machine 2 decreases, the drag speed decreases, and the drag force decreases, keeping the aquaculture rope 5 in a relatively taut state. At the same time, the torque sensor detects and outputs torque and speed in real time, records the rope drag force and drag speed, and the high-speed camera records the pendulum angle and time of the rope under different drag forces, and records the system response time.

[0066] Furthermore, the main principle of the constant tension and variable load joint adjustment electric control system for mainly jointly regulating the first drag rope machine 2 and the second drag rope machine 6 is as follows: 1. Edit the control programs of the PLC and the touch panel; 2. Start the variable-frequency motor 202 without load (the air compressor has no air pressure, that is, the brake disc 11 has no load) to make the first drag rope machine 2 and the second drag rope machine 6 operate stably. At this time, the first torque sensor 203 and the second torque sensor 603 can detect the starting torque of the first winch 204 and the second winch 604; 3. Input the load value on the touch panel, and after the operation of the PLC, control the air compressor to input the corresponding air pressure, so that the brake disc 11 outputs the corresponding load torque to act on the second winch 604, and the real torque is fed back to the PLC through the second torque sensor 603 to make a micro-adjustment to the air compressor; 4. At the same time, the first winch 204 is subjected to load, the torque value output by the first torque sensor 203 becomes larger and is fed back to the PLC, and the PLC controls the variable-frequency motor to increase the output torque. For details, please refer to Figure 15 。

[0067] In summary, the present invention designs a land-based constant tension test bench system, which realizes the relative stability of the tension of the aquaculture rope with finished kelp under variable load conditions, or automatically pauses the drag when the drag is stuck, avoiding the pendulum of the aquaculture rope 5 being cut by the tool due to the sudden disappearance of the force or being pulled off due to excessive force. At the same time, the device can accurately measure the pendulum speed and angle of the aquaculture rope 5 under different stress states during the movement process of the aquaculture rope 5, providing a reference basis for actual offshore applications and ensuring the safety of the aquaculture rope 5 during the dragging process without damage.

[0068] The above embodiments are only illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. All equivalent modifications or changes made by those with ordinary knowledge in the technical field to which the present invention pertains without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A constant tension control device for large algae cultivation rope under variable load, characterized in that: The invention comprises a bottom plate (1), on which a first rope-pulling machine (2) for maintaining the tension of a cultivation rope (5) during the harvesting of large algae is provided, a second rope-pulling machine (6) for simulating the load force applied to the cultivation rope (5) when the first rope-pulling machine (2) drags the cultivation rope (5) during the harvesting of large algae, and a rope-releasing machine (7) located between the first rope-pulling machine (2) and the second rope-pulling machine (6) and for winding up the cultivation rope (5), a supporting pulley (3) slidably connected to the cultivation rope (5) is further provided between the first rope-pulling machine (2) and the second rope-pulling machine (6), a cutting knife (4) for cutting off large algae attached to the cultivation rope (5) is provided at the top end of the supporting pulley (3), and the driving motors in the first rope-pulling machine (2) and the second rope-pulling machine (6) are both connected to a PLC controller.

2. The constant tension control device for large algae cultivation rope under variable load according to claim 1, characterized in that: The first rope pulling machine (2) comprises a first base frame (201), a variable frequency motor (202) mounted on the first base frame (201), a first torque sensor (203) and a first winch (204) in sequence, the output shaft of the variable frequency motor (202) being connected to the first output shaft of the first torque sensor (203) via a first coupling (205), the second output shaft of the first torque sensor (203) being connected to a first rotating shaft (208) via a second coupling (206), the end of the first rotating shaft (208) away from the first torque sensor (203) being inserted into the first winch (204), and the first winch (204) being provided with a first traction disc (8).

3. The constant tension control device for large algae cultivation rope under variable load according to claim 1, characterized in that: The second rope pulling machine (6) comprises a second base frame (601), a servo motor (602) mounted on the second base frame (601) in sequence, a second torque sensor (603) and a second winch (604); the output shaft of the servo motor (602) is connected to a second rotating shaft (611); the end of the second rotating shaft (611) away from the servo motor (602) is connected to the first output shaft of the second torque sensor (603) via a third coupling (608); the second output shaft of the second torque sensor (603) is connected to a third rotating shaft (612) via a fourth coupling (609); the end of the third rotating shaft (612) away from the second torque sensor (603) is inserted into the second winch (604); and the second winch (604) is provided with a second traction disc (9).

4. The constant tension control device for large algae cultivation rope under variable load according to claim 3, characterized in that: An electromagnetic clutch (605) located on the side of the third coupling (608) is provided on the end of the second rotating shaft (611) close to the servo motor (602), and a pneumatic brake (606) for providing damping torque is provided between the electromagnetic clutch (605) and the third coupling (608). The pneumatic brake (606) includes a pneumatic component (10) installed on the second base frame (601) and a brake disc (11) mounted on the second rotating shaft (611).

5. A method for controlling the constant tension of a macroalgae cultivation rope under variable load based on the constant tension control device for macroalgae cultivation rope under variable load according to any one of claims 1 to 4, characterized in that: Applied to the second rope pulling machine (6), comprising the following steps: The second rope pulling machine (6) is used to simulate the random change of force value during the large algae harvesting process. The large algae cultivation rope (5) is subjected to the pressure of the traction discs on both sides in the gap of the second rope pulling machine (6). There is no relative sliding between the large algae cultivation rope (5) and the second traction disc (9) on the second rope pulling machine (6). At this time, the electromagnetic clutch (605) is in a released state, and the damping torque of the second rope pulling machine (6) is only provided by the pneumatic brake (606).

6. A method for controlling constant tension of a large algae cultivation rope under variable load according to claim 5, characterized in that: By using the variable load curve pre-set in the PLC controller or manually setting the required load force on the touch screen, the corresponding pressure value is obtained according to the relationship between the theoretical load force and the pressure, and the converted pressure value is output through the model quantity to realize the proportional control of the pneumatic brake (606), thereby achieving the control of the output torque of the second rope pulling machine (6); wherein, when the set load force increases, the pressure increases, the pneumatic brake (606) is tightened, and the output force of the second winch (604) increases; when the set load force decreases, the pneumatic brake (606) is relaxed, and the output force of the second winch (604) decreases, thereby realizing the variable load simulation in the process of harvesting kelp.

7. A method for controlling constant tension of a large algae cultivation rope under variable load according to claim 6, characterized in that: The corresponding pressure value is obtained according to the relationship between the theoretical load force and the pressure, including: The relationship between theoretical load force and pressure is determined according to the following formula: Wherein, P is the air pressure of the air cylinder in the pneumatic component (10); F load is the load force; r2 is the radius of the second traction disc (9); r2' is the distance from the center of the breeding rope (5) to the arc of the second traction disc (9), which is theoretically calculated to be approximately the radius of the breeding rope (5); R is the radius of the air cylinder in the pneumatic component (10); μ is the friction coefficient; S is the definition domain of the brake pad on the brake disc (11), S=S1+S2+S3; x and y are with the center of the brake disc (11) as the origin, the horizontal direction is the X axis, and the vertical direction is the Y axis.

8. The method for controlling the constant tension of a large algae cultivation rope under variable load according to claim 5, characterized in that: Applied to a first rope pulling machine (2), comprising the following steps: The first rope pulling machine (2) is used to maintain the tension of the cultivation rope (5) during the actual harvesting process. When the first rope pulling machine (2) pulls the cultivation rope (5), in order to overcome the damping torque of the second rope pulling machine (6), the first rope pulling machine (2) is rotated. At this time, when the first rope pulling machine (2) rotates, the first traction disk (8) opens to send out the large algae cultivation rope (5), thereby achieving the cultivation rope (5) being dragged with a dragging force; wherein, the first rope pulling machine (2) sets its tensioning force to a fixed value according to the required torque and the size of the winch.

9. A method for controlling constant tension of a large algae cultivation rope under variable load according to claim 8, characterized in that: The relationship between the PLC controller and the dragging speed is dynamically adjusted by the PID control algorithm in the PLC controller. When the dragging force of the first rope-pulling machine (2) decreases, the speed increases, and when the dragging force increases, the speed decreases, thereby maintaining a relatively stable power. When the load force obtained after the numerical value conversion of the first torque sensor (203) in the first rope-pulling machine (2) is less than the set value, the output torque of the variable frequency motor (202) is rapidly increased by adjusting the PID control algorithm. When the load force obtained after the numerical value conversion of the first torque sensor (203) in the first rope-pulling machine (2) is greater than the set value, the output torque of the variable frequency motor (202) is reduced by adjusting the PID control algorithm, thereby achieving constant tension control during the process of harvesting large algae.

10. A method for controlling constant tension of a large algae cultivation rope under variable load according to claim 9, characterized in that: The dynamic adjustment of the relationship between the dragging speed and the dragging speed by the PID control algorithm in the PLC controller includes: The logic control program in the PLC controller adopts the PID control algorithm, through the proportional coefficient (K p )、Integral coefficient (K i ) and differential coefficient (K d ) is used to calculate the input deviation value, and the calculation result is used to control the output; when the feedback signal has a relatively large deviation step, the proportional link and the differential link work at the same time to suppress the feedback input change caused by this deviation step, and at the same time consider adding an integral link to eliminate the residual error; The deviation value e(t) between the set value r(t) and the measured load force f(t) is used as the input signal, and its expression formula is as follows: e(t)=r(t)-f(t); PID control is to control the proportion, integration and differentiation of e(t) through linear combination to form the control quantity, and its output signal is: After Laplace transform, the transfer function of the PID controller is:

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