A control system for an underwater dredging robot and a dredging method thereof

Abstract

The present invention discloses a control system for an underwater dredging robot and a dredging method thereof. The control system includes seven control subsystems, namely a hoisting control subsystem, a robotic arm control subsystem, an excavation control subsystem, a rotation control subsystem, a mud pump pipeline control subsystem, a high-pressure water flushing control subsystem, and a travel control subsystem. The control subsystems respectively control seven devices, namely a vehicle body, a robotic arm, a cutter, a rotation mechanism, a mud pump and pipeline, a high-pressure water flushing pump, and a crawler track, and respectively control the seven devices to perform seven equipment actions, namely vehicle body hoisting, robotic arm lifting and lowering, cutter rotation, cutter lateral movement, mud pump and pipeline transportation, high-pressure water flushing, and crawler track movement. The control system monitors and controls key parameters during the dredging process and provides parameter control methods for different abnormal operation conditions to ensure the safety, efficiency, and stability of the entire dredging operation.

Description

Technical Field

[0001] The present invention belongs to the technical field of dredging engineering, and in particular relates to a control system of an underwater dredging robot and a dredging method thereof. Background Art

[0002] CN113931246A discloses an underwater dredging robot for dredging hard soil, wherein the underwater dredging robot adopts a cutter and a mud pump to perform dredging operations. During the dredging operation, the control of the dredging robot mainly lies in coordinating the excavation output and the conveying volume.

[0003] During the excavation of sand, gravel and other soils, the soil particle size is fixed, that is, the size of the sand and gravel itself is irrelevant to the cutting process. However, during the excavation of hard soil, due to the particularity of hard soil, the control of parameters during the cutting process will directly affect the soil particle size. The soil particle size is in a changing state, making the operating parameters more complex and changeable, bringing new problems to the entire control system.

[0004] Therefore, it is necessary to provide a control system for an underwater dredging robot and a dredging method thereof in view of the particularity of operating parameters during hard soil excavation. Summary of the Invention

[0005] In order to overcome the above-mentioned deficiencies in the prior art, the present invention provides a control system for an underwater dredging robot and a dredging method thereof.

[0006] The technical solution adopted in the present invention is as follows:

[0007] A first aspect of the present invention provides a control system for an underwater dredging robot, the control system comprising seven control subsystems, namely, a hoisting control subsystem, a robotic arm control subsystem, an excavation control subsystem, a rotation control subsystem, a mud pump and pipeline control subsystem, a high-pressure water flushing control subsystem, and a travel control subsystem. The seven control subsystems respectively control seven devices, namely, a vehicle body, a robotic arm, a cutter, a rotation mechanism, a mud pump and pipeline, a high-pressure water flushing pump, and a crawler, and respectively control the corresponding seven devices to perform seven equipment actions, namely, vehicle body hoisting, robotic arm lifting and lowering, cutter rotation, cutter lateral movement, mud pump and pipeline transportation, high-pressure water flushing, and crawler movement.

[0008] The underwater dredging robot includes two core links in the dredging of hard soil: excavating the hard soil and transporting the hard soil. The robotic arm control subsystem, the excavation control subsystem, and the rotation control subsystem cooperate to control the auger to cut and stir the hard soil. The mud pump pipeline control subsystem controls the mud pump to suck up the cut hard soil together with the surrounding water and transport it out through the pipeline.

[0009] Among them, the robotic arm control subsystem, excavation control subsystem and rotation control subsystem cooperate to control the excavation output of hard soil, the particle size of the cut hard soil and the cutting force exerted on the auger; the excavation output is combined with the parameters of the mud pump and pipeline, namely the mud pump-flow characteristic curve, the mud pump speed, and the length and diameter of the pipeline to further calculate the slurry flow rate, delivery concentration and delivery flow in the pipeline. The delivery volume of the mud pump and pipeline simultaneously limits the excavation output of hard soil to avoid blockage.

[0010] Furthermore, during the excavation of hard soil, the robotic arm control subsystem controls the robotic arm to descend to increase the burial depth of the auger, thereby improving excavation output; the rotation control subsystem controls the rotation mechanism to increase the transverse movement speed of the auger, thereby improving excavation output.

[0011] Furthermore, the excavation control subsystem controls the rotation speed of the auger, and the rotation control subsystem controls the transverse speed of the auger. The two together control the particle size a of the hard soil cut down, which is calculated as follows:

[0012]

[0013] In formula (1), V s is the speed of the reamer's transverse movement, n is the reamer's rotational speed, and m is the number of rows of teeth on the reamer.

[0014] Furthermore, the head-flow characteristic curve of the mud pump is different when it runs at different speeds. According to the proportionality law, The mud pump pipeline control subsystem controls the mud pump to increase its rotation speed, thereby increasing the conveying flow in the pipeline.

[0015] Furthermore, the delivery concentration in the pipeline is controlled at 11-17%.

[0016] Furthermore, the combined speed of the traverse speed of the reamer and the linear speed of the reamer tooth tip is the soil particle speed, and the linear speed of the reamer tooth tip = 2πR*n, where n is the reamer rotation speed and R is the reamer radius; the upper limit of the soil particle speed is 30% of the suction port flow rate. The specific formula is as follows:

[0017] V 土粒速度 ≤30%V 吸口流速 (2)

[0018] V 吸口流速 =Q 输送流量 / S 吸口面积 (3)

[0019] In formula (3), S 吸口面积 is the suction area of ​​the pipe suction port inside the reamer, S 吸口面积 is a constant.

[0020] Furthermore, the delivery concentration in the pipeline is combined with the soil particle size, and the critical flow velocity is calculated through an empirical formula, and the slurry flow rate in the pipeline is 1.1-1.5 times the critical flow velocity; at the same time, the reamer is driven by an electric motor or a hydraulic motor, and the cutting force of the reamer is limited by the structural strength. The maximum allowable value of the power of the reamer is the rated power of the motor or hydraulic motor.

[0021] Furthermore, during the dredging process of the underwater dredging robot, the slurry flow rate, conveying concentration, soil particle speed and auger power in the pipeline are monitored. Under abnormal working conditions, the auger speed, auger lateral movement speed, robotic arm lifting and lowering and mud pump speed are regulated by the excavation control subsystem, rotation control subsystem, robotic arm control subsystem and mud pump pipeline control subsystem respectively to ensure that the entire dredging operation is carried out safely, efficiently and stably.

[0022] Furthermore, different control methods are adopted in the following five situations:

[0023] (1) When the slurry flow rate is less than 1.1*critical flow rate and the delivery concentration is high, the slurry pump control subsystem is used to increase the speed of the slurry pump to quickly increase the slurry flow rate. Then, the rotary control subsystem is used to reduce the speed of the auger to reduce the soil particle size and the critical flow rate. At the same time, the excavation output is also reduced, thereby reducing the delivery concentration.

[0024] (2) When the slurry flow rate is less than 1.1*critical flow rate and the delivery concentration is low, the excavation control subsystem is used to increase the auger speed and reduce the soil particle size. At the same time, it is necessary to avoid the auger power exceeding its maximum allowable value, calculate the soil particle velocity, and avoid it exceeding the upper limit of the soil particle velocity to avoid a large amount of omission.

[0025] (3) When the slurry flow rate is greater than 1.5*critical flow rate and the delivery concentration is high, the mud pump pipeline control subsystem is used to reduce the speed of the mud pump to reduce energy waste; secondly, the excavation control subsystem is used to reduce the speed of the auger and the power of the auger, further reducing energy consumption while meeting the dredging requirements; finally, the rotation control subsystem is used to reduce the speed of the auger's transverse movement to reduce the delivery concentration and avoid a sudden increase in concentration and pipe blockage.

[0026] (4) When the slurry flow rate is greater than 1.5*critical flow rate and the delivery concentration is low, the slewing control subsystem is used to increase the speed of the auger's transverse movement to increase the excavation output. However, it is necessary to prevent the auger's power from exceeding its maximum allowable value, and to calculate the soil particle velocity and prevent it from exceeding the upper limit of the soil particle velocity to avoid a large amount of omissions. Secondly, the manipulator control subsystem is used to control the manipulator arm to descend and increase the burial depth of the auger to increase the excavation output. If the slurry flow rate is still high after the delivery concentration is increased, the third situation is used for control.

[0027] (5) When the auger power suddenly increases due to the sudden hardening of the soil, the slewing control subsystem is used to reduce the lateral speed of the auger, and the excavation control subsystem is used to increase the auger speed within the allowable power range of the auger. The soil particle speed is calculated and prevented from exceeding the upper limit of the soil particle speed to avoid a large amount of omission.

[0028] A second aspect of the present invention provides a dredging method using an underwater dredging robot, characterized in that it comprises the following steps:

[0029] ① Prepare the vehicle: Start the auger, mud pump, and high-pressure water pump in sequence; set the auger speed and mud pump speed according to the soil hardness and required excavation depth, adjust the mechanical arm to bury the auger in the soil, and adjust it to the appropriate working height and angle;

[0030] ② Horizontal sweeping: After the preparatory work is completed, dredging begins. The operating parameters are optimized according to the soil conditions. Based on the matching relationship between excavation output and conveying volume, the slewing mechanism is controlled to rotate horizontally to the left or right at a certain rotation speed. The slewing mechanism drives the auger to move horizontally. At the same time, the auger rotates to gradually cut off the hard soil. The cut soil blocks are pumped away by the mud pump. At this time, the four equipment actions of auger rotation, high-pressure water flushing, mud pump conveying, and auger horizontal movement are carried out simultaneously.

[0031] ③Shift: Keep the three actions of reamer rotation, high-pressure water flushing and mud pumping running continuously, and control the crawler to make the whole vehicle move forward; at this time, the four actions of reamer rotation, high-pressure water flushing, mud pumping and crawler movement are performed simultaneously;

[0032] ④Completion: Repeat the above operation process to complete the dredging of the next section.

[0033] The beneficial effects of the control system of the underwater dredging robot and the dredging method thereof of the present invention are as follows:

[0034] This invention proposes an automatic control system for underwater dredging robots for the first time. By leveraging this technology, it automates underwater dredging operations, improving dredging efficiency and reducing labor costs while ensuring equipment safety. The control system for underwater dredging robots addresses the complexities of operational parameter analysis caused by variations in particle size during hard soil transport. By monitoring and controlling key parameters during the dredging process and providing methods for controlling these parameters under various abnormal operating conditions, the system ensures the safety, efficiency, and stability of the entire dredging operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is the control system diagram of the underwater dredging robot.

[0036] Figure 2 This is the control flow chart for hard soil excavation and transportation of underwater dredging robot.

[0037] Figure 3 Schematic diagram of the cross section of the reamer cutting process.

[0038] Figure 4 This is the matching diagram of the mud pump pipeline transportation system.

[0039] Figure 5 This is the working concentration curve of the mud pump pipeline transportation system.

[0040] Figure 6 This is the working flow curve of the mud pump pipeline transportation system.

[0041] Figure 7 This is a diagram of the control method for dredging operations of an underwater dredging robot. DETAILED DESCRIPTION

[0042] The following clearly and completely describes the technical solutions in the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0043] Example 1: A control system for an underwater dredging robot for dredging hard soil

[0044] The present invention discloses a control system for an underwater dredging robot for dredging hard soil. Figure 1 As shown, the control system includes seven control subsystems, namely, a hoisting control subsystem, a robotic arm control subsystem, an excavation control subsystem, a rotation control subsystem, a mud pump pipeline control subsystem, a high-pressure water flushing control subsystem and a walking control subsystem. The control subsystems respectively control seven devices, namely, the vehicle body, the robotic arm, the reamer, the rotation mechanism, the mud pump and pipeline, the high-pressure water flushing pump, and the crawler, and respectively control the corresponding seven devices to perform seven equipment actions, namely, vehicle body hoisting, robotic arm lifting and lowering, reamer rotation, reamer transverse movement, mud pump and pipeline transportation, high-pressure water flushing and crawler movement.

[0045] The hard soil excavation and transportation control process of the underwater dredging robot is as follows Figure 2 As shown, the underwater dredging robot includes two core links in the dredging of hard soil: excavating hard soil and transporting hard soil. The robotic arm control subsystem, the excavation control subsystem and the rotation control subsystem cooperate to control the auger to cut and stir the hard soil. The mud pump pipeline control subsystem controls the mud pump to suck up the cut hard soil together with the surrounding water and transport it out through the pipeline.

[0046] The robotic arm control subsystem, excavation control subsystem, and rotation control subsystem collaboratively control the excavation output of hard soil, the particle size of the cut hard soil, and the cutting force applied to the auger. This excavation output is combined with the parameters of the mud pump and pipeline, namely the mud pump-flow characteristic curve, mud pump speed, and the length and diameter of the pipeline, to further calculate the slurry flow rate, delivery concentration, and delivery flow rate within the pipeline. The delivery volume of the mud pump and pipeline also limits the excavation output of hard soil to prevent clogging. In summary, the hard soil delivery capacity and hard soil excavation capacity influence and restrict each other.

[0047] In addition to excavation and transportation, a comprehensive analysis of four key aspects is required: overall layout, structural design and strength verification, power matching, and anti-overturning capability. Each element works together to form an organic whole, creating a complete dredging robot capable of dredging hard soil.

[0048] Preferably, in order to smoothly transport hard soil, the mud pump should use a slurry pump with strong flow capacity and high head, the pipeline should use a steel wire hose with a smooth inner wall, moderate diameter and sufficient strength, and the pipeline should be arranged reasonably to minimize local head loss.

[0049] The following analysis uses an underwater dredging robot as an example to analyze its control system during the excavation and transportation of hard soil. It also provides control methods for various abnormal operating conditions to ensure the safety, efficiency, and stability of the entire dredging operation. The auger used in this underwater dredging robot has a diameter of 300 mm and the conveying pipe has a diameter of 100 mm.

[0050] Example 2: Analysis of the control system of the underwater dredging robot during excavation of hard soil

[0051] (1) Relationship between the auger rotation speed and auger transverse speed and soil particle size

[0052] The cross-sectional diagram of the reamer cutting process is shown in Figure 2. Figure 3 As shown in the figure, the cutting trajectory of all the teeth on the reamer rotates one circle. Each trajectory line is equivalent to the previous trajectory line translated in the cutting direction by the same length, that is, the cutting thickness. If the cutting thickness is a, it can be expressed by the formula:

[0053]

[0054] In formula (1), m is the number of rows of teeth on the reamer, Figure 3 Where m is 6; n is the reamer speed r / min; a is in m; V s is the traverse speed of the reamer in m / s.

[0055] The present invention has found in experiments that the soil particles formed after the hard soil is cut are closely related to the shape of the blade teeth. In the present invention, most of the soil particles are in the form of sheets with the same width as the blade teeth, and the thickness is basically the same as the cutting thickness. The broken soil initially cut off is basically in the form of strips. After being transported through the grid, mud pump and pipeline, the soil strips break. When observed from the pipeline outlet, the soil particles still retain a certain size and are irregular blocks. The blocks are basically still of thickness a. The particle size of the actual transported soil can be considered to be a. The smaller the soil particle size a, that is, the smaller the thickness of the soil layer cut by a single blade tooth, the smaller the cutting force, and the smaller the soil particles formed after the hard soil is cut, the more conducive to inhalation and transportation.

[0056] (2) The relationship between the reamer speed, the lifting and lowering of the robotic arm (i.e., the reamer burial depth), the reamer lateral movement speed, and the cutting force

[0057] Referring to the cutting force calculation method in the reference "Analysis of Cutter Head Loads of Cutter Suction Dredger Based on Two-Dimensional Cutting Theory", the three-dimensional force acting on the entire cutter during the excavation process is calculated by combining the cutter speed, the lifting and lowering of the robotic arm (i.e., the cutter burial depth), the speed of the cutter's lateral movement, and the soil cohesion. On this basis, the cutting torque, cutting power, and excavation output of the cutter at different times are obtained, and the calculation results change dynamically over time.

[0058] The accuracy of the calculation method was verified by the test of reamer cutting hard soil. The experimental results are shown in Table 1 below.

[0059] Table 1: Test results of reamer cutting hard soil

[0060]

[0061] Furthermore, the above method is used to calculate the force, cutting torque, cutting power, excavation output, and soil particle size of the auger carried by the underwater dredging robot under typical preset working conditions (specific conditions include soil cohesion, auger traverse speed, auger speed, and auger burial depth). The specific conditions are shown in Table 2. In the following calculation, the soil cohesion is 150 kPa and the number of tooth rows on the auger used is 6.

[0062] Table 2: Calculation results of the reamer mathematical model for typical preset working conditions

[0063]

[0064] The rotation of the reamer controlled by the excavation control subsystem is usually driven by an electric motor or a hydraulic motor. In the process of desilting hard soil, the reamer is subjected to large cutting force due to the hard soil. In order to reduce the soil particle size and ensure the excavation output, the reamer speed is often high, which brings a large load to the reamer. Therefore, the cutting force of the reamer is often limited by the structural strength. In the present invention, the maximum allowable value of the reamer power is the rated power of the electric motor or hydraulic motor.

[0065] (3) The relationship between the speed of the traverse of the cutter and the lifting and lowering of the mechanical arm (i.e., the depth of the cutter buried) and the excavation output

[0066] During the excavation of hard soil, the manipulator control subsystem controls the manipulator to descend, the auger burial depth increases, and the excavation output improves, as shown in working conditions 3 and 4 in Table 2 above; the auger lateral movement speed of the rotation control subsystem increases, and the excavation output improves, as shown in working conditions 1 and 2 in Table 2 above.

[0067] (4) Maximum allowable value of soil particle velocity

[0068] In the present invention, a pipe suction port is provided on the inner side of the reamer, which can better suck the mixed slurry into the pipe and reduce the amount of leakage. However, due to the influence of the traverse speed of the reamer and the rotation speed of the reamer, the soil particles cut off follow the reamer teeth and obtain the soil particle speed to be thrown out of the reamer. The soil particle speed is the combined speed of the traverse speed of the reamer and the linear speed of the reamer tooth tip. In order to reduce the amount of leakage, the soil particle speed needs to be much smaller than the suction port flow rate, generally not exceeding 30% of the suction port flow rate. The specific formula is as follows:

[0069] V 绞刀齿尖线速度 =2πR*n 绞刀转速 (2)

[0070]

[0071] V 土粒速度 ≤30%V 吸口流速 (4)

[0072] V 吸口流速 =Q 输送流量 / S 吸口面积 (5)

[0073] In formula (2), R is the radius of the cutter; in formula (5), S 吸口面积 is a constant.

[0074] Example 3: Analysis of the control system of the underwater dredging robot during the transportation of hard soil

[0075] (1) Critical flow velocity and slurry flow velocity in the pipeline

[0076] The critical flow velocity is calculated using the standard formula (JTS 181-5-2012), which is as follows:

[0077] V c =(90C V ) 1 / 3 ·g 1 / 4 ·D 1 / 2 ·ω 1 / 2 ·d m -1 / 4 (6)

[0078] Formula (6), V c -critical flow rate; C v - slurry concentration, g-gravitational acceleration; d m is the soil particle diameter, ω is the sediment particle settling velocity, and the Wushui formula is used for calculation:

[0079]

[0080] In formula (7), ν is the kinematic viscosity coefficient, which is 10 -6 m 2 / s; g-gravitational acceleration, take 9.8m / s 2 ; γ s - transported solid particle density, the object used in this invention is mainly soil, take 2650kg / m 3 ; γ w - Bulk density of the transport medium, in this invention it is mainly water, take 1000kg / m 3 .

[0081] The critical velocity is proportional to the soil particle size (i.e., the diameter of the soil particles). Because hard soil has larger particle sizes and different properties from conventional sand and stone, the critical velocity calculated using empirical formulas can be used as a reference. The slurry flow rate needs to be appropriately increased, preferably 1.1-1.5 times the critical velocity.

[0082] (2) Mud pump and pipeline matching calculation

[0083] Calculate the friction loss according to Wilson's friction loss calculation formula. The specific formula is as follows:

[0084]

[0085] In formula (8), I m - slurry friction loss; I W -Friction loss of clean water; γ m - solid particle density; γ w - water density; C vd - slurry concentration; V m - Slurry flow rate.

[0086] Taking a pipeline with a diameter of 100 mm, a row spacing (i.e., a length of the pipeline) of 100 mm, and a row height of 5 m as an example for analysis, the friction loss is calculated by formula (8), and then the relationship curve of pipeline head loss-flow rate is calculated based on the friction loss. It is then matched with the head-flow characteristic curve of the mud pump. As the conveying concentration increases, the mud pump head gradually decreases, while the pipeline head loss gradually increases. The intersection of the two curves is the working point at that concentration, as shown in Figure 1. Figure 4Connect the working points to form a curve, and get the working curve with one-to-one correspondence between concentration, flow rate and head, as shown in Figure 5 and Figure 6 As shown by Figure 6 It can be seen that the working flow after matching is 40-120m 3 / h, that is, the flow rate is 1.42-4.25m / s. And the delivery flow rate should be higher than 1.3 times the critical flow rate calculated by formula (6) (taking 1.3 times as an example), so the delivery flow rate should be higher than 2.1m / s, that is, the flow rate is higher than 60m 3 / h, by Figure 5 It can be seen that the corresponding concentration is 22%. Therefore, under this working condition, the conveying concentration range is 0-22%, and the conveying flow range is 60-120m 3 / h.

[0087] In summary, in actual operations, for the selected mud pump and pipeline system, there is an appropriate conveying concentration range and conveying flow range in the process of conveying hard soil. Within this range, the smooth progress of the conveying process can be guaranteed without clogging.

[0088] For the underwater dredging robot of the present invention, the delivery concentration within the pipeline should be controlled at 11-17% to avoid pipe blockage and low production. Furthermore, for the selected mud pump, the appropriate pipeline length and diameter can be selected based on the operating curve, depending on the requirements of a wide delivery concentration range and moderate flow rate.

[0089] (3) The relationship between the speed of the mud pump and the delivery flow in the pipeline

[0090] The head-flow characteristic curve of the mud pump is different when it runs at different speeds. According to the proportional law, The mud pump pipeline control subsystem controls the mud pump to increase its rotation speed, thereby increasing the conveying flow in the pipeline.

[0091] Example 4: Control method used by the control system of the underwater dredging robot under abnormal working conditions

[0092] The above analysis demonstrates that the underwater dredging robot's ability to excavate and transport hard soils influences and limits each other. During the dredging process, the underwater dredging robot monitors the slurry flow rate and transport concentration within the pipeline, as well as the velocity of soil particles and the power of the auger. Under abnormal operating conditions, the excavation control subsystem, the rotation control subsystem, the robotic arm control subsystem, and the dredge pump pipeline control subsystem regulate the auger speed, traverse speed, robotic arm elevation, and dredge pump speed, ensuring the entire dredging operation is carried out safely, efficiently, and stably.

[0093] Different control methods are adopted in the following five situations, as follows:

[0094] (1) If the slurry flow rate is less than 1.1*critical flow rate and the delivery concentration is high, there is a risk of pipe blockage. The slurry pump speed should be increased through the slurry pump control subsystem to quickly increase the slurry flow rate. Secondly, the auger traverse speed should be reduced through the rotation control subsystem to reduce the soil particle size, reduce the critical flow rate, reduce the excavation output, and thus reduce the delivery concentration.

[0095] (2) If the slurry flow rate is less than 1.1*critical flow rate and the delivery concentration is low, the delivery efficiency is extremely low and stratified flow is likely to have formed. This is mainly caused by the large soil particle size. Therefore, the auger speed should be increased through the excavation control subsystem to reduce the soil particle size, rather than increasing the mud pump speed through the mud pump pipeline control subsystem first. Otherwise, the concentration will be further reduced, causing the system to always be in an inefficient working state. At the same time, it is necessary to avoid the auger power exceeding its maximum allowable value, and calculate the soil particle velocity and avoid it exceeding the upper limit of the soil particle velocity to avoid a large amount of omission.

[0096] (3) If the slurry flow rate is greater than 1.5*critical flow rate and the delivery concentration is high, it is likely that the transported soil particles are easy to transport. First, the mud pump speed should be reduced through the mud pump pipeline control subsystem to reduce energy waste; secondly, the auger speed should be reduced through the excavation control subsystem, which can reduce the auger power and further reduce energy consumption while meeting the dredging requirements; finally, the auger transverse movement speed can be appropriately reduced through the rotation control subsystem to appropriately reduce the delivery concentration and avoid the sudden increase in concentration and the occurrence of pipe blockage;

[0097] (4) If the slurry flow rate is higher than 1.5*critical flow rate and the delivery concentration is low, it is mainly because the excavation output is low at this time. First, the traverse speed of the auger should be increased through the rotation control subsystem to increase the output. However, it is necessary to avoid the auger power exceeding its maximum allowable value, and calculate the soil particle speed and avoid it exceeding the upper limit of the soil particle speed to avoid a large amount of omissions. Secondly, the manipulator control subsystem can be used to appropriately control the descent of the manipulator to increase the burial depth of the auger to increase the excavation output. If the slurry flow rate is still high after the delivery concentration is increased, it can be regulated according to the third situation.

[0098] (5) If the auger power suddenly increases, this is most likely due to the sudden hardening of the soil. The slewing control subsystem should be used to reduce the auger's lateral speed, and the excavation control subsystem should be used to increase the auger's rotation speed within the auger's power allowable range. The soil particle speed should be calculated and avoided to exceed the upper limit of the soil particle speed to avoid a large amount of omission.

[0099] Example 5: Dredging method based on the control system of the underwater dredging robot

[0100] The specific dredging method of the underwater dredging robot for dredging hard soil under the above control system is as follows. Before dredging construction, parameters that constrain or select the dredging process are set. The parameters include excavation performance, conveying performance, and walking performance. The specific settings are shown in Table 3.

[0101] Table 3: Performance parameters

[0102]

[0103] (1) Transport the entire robot system to the designated operation area, and place the water drive and control parts on the ship deck; connect to the 380V power supply, take waterproof measures, and ensure the safety of electricity and oil; and arrange the control platform;

[0104] (2) Place the underwater robot in the dredging site through the lifting frame, start the power supply, observe the underwater situation, and control the underwater robot to move to the target soil;

[0105] (3) Carry out dredging operations. The dredging control methods are as follows: Figure 7 shown.

[0106] ① Prepare the vehicle: first start the necessary equipment, and start the auger (speed 40r / min), mud pump (maximum speed), and high-pressure water pump (maximum speed) in sequence until the mud pipe discharges clean water; according to the soil hardness and the required excavation depth, set the auger speed and mud pump speed (for hard soil with a soil cohesion of 100kPa, the auger speed is set to 60r / min, the mud pump speed is temporarily turned to the maximum, and the high-pressure water pump is turned to the maximum), adjust the robotic arm so that the auger is buried in the soil, and adjust to the appropriate working height (adjustable range is 0-1.3m) and angle (the auger is controlled by a two-joint robotic arm, so the same height can have different inclination angles, and the distance between the auger and the vehicle body rotation center is also different, that is, the rotation radius is different, and the adjustable range is 1.8-2.5m, so it can be flexibly adjusted according to the soil distribution).

[0107] ② Horizontal sweeping: After the preparatory work is completed, silt removal begins. The operating parameters are optimized according to the soil conditions. Based on the matching relationship between excavation output and conveying volume, the slewing mechanism is controlled to rotate horizontally to the left or right at a certain rotation speed. The slewing mechanism drives the auger to move horizontally. At the same time, the auger rotates to gradually cut off the hard soil. The cut soil blocks are pumped away by the mud pump. The auger excavation volume and pipeline conveying volume under different operating parameter combinations are shown in Table 4, where the suction coefficient is the ratio of the suction volume to the actual excavation volume, and the soil cutting coefficient is the ratio of the actual excavation volume to the theoretical excavation volume.

[0108] At this point, the four equipment actions of auger rotation, high-pressure water flushing, mud pumping, and auger lateral movement are executed simultaneously. The default maximum swing angle of the auger is plus or minus 30 degrees, with a limit switch, and the swing angle can be modified according to excavation requirements. At the same time, the auger is monitored in real time during construction for any indestructible walls and pile foundations on both sides of the vehicle body to avoid collisions during rotation. The direction of rotation is observed for obstacles, the swing angle is monitored, and before reaching the maximum angle, the auger is decelerated and moved horizontally in the opposite direction to change the excavation height.

[0109] Table 4: Table of reamer excavation volume and pipeline transportation volume under different operating parameter combinations

[0110]

[0111] After cutting a layer of soil, keep the auger, high-pressure water pump, and mud pump running continuously, adjust the mechanical arm, and change the vertical position of the auger (the parameters still follow Table 4), cutting layer by layer from top to bottom, and so on, until the excavation is completed. At this time, the four equipment actions of auger rotation, high-pressure water flushing, mud pump transportation, and mechanical arm lifting are carried out simultaneously;

[0112] ③ Shift: Keep the three actions of auger rotation, high-pressure water flushing and mud pumping running continuously, control the crawler tracks to make the entire vehicle body move forward at a very slow speed (0-1km / h) for a short distance, allowing climbing dredging at a maximum angle of 30°. At this time, the four actions of auger rotation, high-pressure water flushing, mud pumping and crawler movement are performed simultaneously.

[0113] ④Completion: Repeat the above operation process to complete the dredging of the next section.

[0114] (4) For wider soils, after completing a trench according to the above steps, the robot needs to return to its original path, and pay attention to the recovery of each pipe system;

[0115] (5) Move the robot to the undrained soil and continue the dredging operation until all the soil is cleared, and then lift the robot out;

[0116] (6) Clean dirt and debris and perform maintenance on the robot.

[0117] The control system designed to run on the main PLC system can remotely control all equipment on site. Each control subsystem can observe the real-time working status of the robot underwater by opening the computer construction interface, and can also perform actions such as adding and drawing background files of the construction area.

[0118] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention are included in the scope of protection of the present invention.

Claims

1. A control system for an underwater dredging robot, characterized in that: The control system includes seven control subsystems, namely, a hoisting control subsystem, a mechanical arm control subsystem, an excavation control subsystem, a rotation control subsystem, a mud pump pipeline control subsystem, a high-pressure water flushing control subsystem, and a travel control subsystem. The seven control subsystems respectively control seven devices, namely, the vehicle body, the mechanical arm, the reamer, the rotation mechanism, the mud pump and pipeline, the high-pressure water flushing pump, and the crawler, and respectively control the corresponding seven devices to perform seven equipment actions, namely, vehicle body hoisting, mechanical arm lifting and lowering, reamer rotation, reamer transverse movement, mud pump and pipeline transportation, high-pressure water flushing, and crawler movement; The underwater dredging robot includes two core links in the dredging of hard soil: excavating the hard soil and transporting the hard soil. The robotic arm control subsystem, the excavation control subsystem, and the rotation control subsystem cooperate to control the auger to cut and stir the hard soil. The mud pump pipeline control subsystem controls the mud pump to suck up the cut hard soil together with the surrounding water and transport it out through the pipeline. The robotic arm control subsystem, excavation control subsystem, and rotation control subsystem collaboratively control the excavation output of hard soil, the particle size of the cut hard soil, and the cutting force applied to the auger. The excavation output is combined with the parameters of the mud pump and pipeline, namely the mud pump-flow characteristic curve, mud pump speed, and the length and diameter of the pipeline, to further calculate the slurry flow rate, delivery concentration, and delivery flow rate within the pipeline. The delivery volume of the mud pump and pipeline simultaneously limits the excavation output of hard soil to avoid clogging. The excavation control subsystem controls the rotation speed of the auger, and the rotation control subsystem controls the transverse speed of the auger. Together, the two control the particle size of the hard soil cut down. , the calculation formula is as follows: In formula (1), is the traverse speed of the reamer, n is the rotation speed of the reamer, m The number of rows of teeth on the reamer.

2. The control system of the underwater dredging robot according to claim 1, characterized in that: During the excavation of hard soil, the manipulator control subsystem controls the manipulator to descend to increase the burial depth of the auger, thereby improving the excavation output; the rotation control subsystem controls the rotation mechanism to increase the transverse movement speed of the auger, thereby improving the excavation output.

3. The control system of the underwater dredging robot according to claim 2, characterized in that: The head-flow characteristic curve of the mud pump is different when it runs at different speeds. According to the proportional law, The mud pump pipeline control subsystem controls the mud pump to increase its rotation speed, thereby increasing the delivery flow in the pipeline.

4. The control system of the underwater dredging robot according to claim 3, characterized in that: The delivery concentration in the pipeline is controlled at 11-17%.

5. The control system of the underwater dredging robot according to claim 4, characterized in that: The combined speed of the traverse speed of the cutter and the linear speed of the cutter tooth tip is the soil particle speed. The linear speed of the cutter tooth tip = 2πR*n, where n is the cutter rotation speed and R is the cutter radius. The upper limit of the soil particle speed is 30% of the suction port flow rate. The specific formula is as follows: In formula (3), is the suction area of ​​the pipe suction port inside the reamer, is a constant.

6. The control system of the underwater dredging robot according to claim 5, characterized in that: The critical flow velocity is calculated by combining the delivery concentration and soil particle size in the pipeline through an empirical formula, and the slurry flow rate in the pipeline is 1.1-1.5 times the critical flow velocity; at the same time, the reamer is driven by an electric motor or a hydraulic motor, and the cutting force of the reamer is limited by the structural strength. The maximum allowable value of the power of the reamer is the rated power of the electric motor or hydraulic motor.

7. The control system of the underwater dredging robot according to claim 6, characterized in that: During the dredging process of the underwater dredging robot, the slurry flow rate, conveying concentration, soil particle speed and auger power in the pipeline are monitored. Under abnormal working conditions, the excavation control subsystem, rotation control subsystem, robotic arm control subsystem and mud pump pipeline control subsystem are used to regulate the auger speed, auger lateral movement speed, robotic arm lifting and lowering and mud pump speed to ensure that the entire dredging operation is carried out safely, efficiently and stably.

8. The control system of the underwater dredging robot according to claim 7, characterized in that: Different control methods are used in the following five situations: (1) When the slurry flow rate is less than 1.1*critical flow rate and the delivery concentration is high, the slurry pump control subsystem is used to increase the speed of the slurry pump to quickly increase the slurry flow rate. Then, the rotary control subsystem is used to reduce the speed of the auger to reduce the soil particle size and the critical flow rate. At the same time, the excavation output is also reduced, thereby reducing the delivery concentration. (2) When the slurry flow rate is less than 1.1*critical flow rate and the delivery concentration is low, the excavation control subsystem is used to increase the auger speed and reduce the soil particle size. At the same time, it is necessary to avoid the auger power exceeding its maximum allowable value, calculate the soil particle velocity, and avoid it exceeding the upper limit of the soil particle velocity to avoid a large amount of omission. (3) When the slurry flow rate is greater than 1.5*critical flow rate and the delivery concentration is high, the mud pump pipeline control subsystem is used to reduce the speed of the mud pump to reduce energy waste; secondly, the excavation control subsystem is used to reduce the speed of the auger and the power of the auger, further reducing energy consumption while meeting the dredging requirements; finally, the rotation control subsystem is used to reduce the speed of the auger's transverse movement to reduce the delivery concentration and avoid a sudden increase in concentration and pipe blockage. (4) When the slurry flow rate is greater than 1.5*critical flow rate and the delivery concentration is low, the slewing control subsystem is used to increase the speed of the auger's transverse movement to increase the excavation output. However, it is necessary to prevent the auger's power from exceeding its maximum allowable value, and to calculate the soil particle velocity and avoid it from exceeding the upper limit of the soil particle velocity to avoid a large amount of omissions. Secondly, the manipulator control subsystem is used to control the manipulator arm to descend and increase the burial depth of the auger to increase the excavation output. If the slurry flow rate is still high after the delivery concentration is increased, the third situation is used for control. (5) When the auger power suddenly increases due to the sudden hardening of the soil, the slewing control subsystem is used to reduce the traverse speed of the auger, and the excavation control subsystem is used to increase the auger speed within the allowable power range of the auger. The soil particle speed is calculated and prevented from exceeding the upper limit of the soil particle speed to avoid a large amount of omission.

9. A dredging method based on the control system of the underwater dredging robot according to claims 1 to 8, characterized in that: The following steps are involved: ① Prepare the vehicle: Start the auger, mud pump, and high-pressure water pump in sequence; set the auger speed and mud pump speed according to the soil hardness and required excavation depth, adjust the mechanical arm to bury the auger in the soil, and adjust it to the appropriate working height and angle; ② Horizontal sweeping: After the preparatory work is completed, dredging begins. The operating parameters are optimized according to the soil conditions. Based on the matching relationship between excavation output and conveying volume, the slewing mechanism is controlled to rotate horizontally to the left or right at a certain rotation speed. The slewing mechanism drives the auger to move horizontally. At the same time, the auger rotates to gradually cut off the hard soil. The cut soil blocks are pumped away by the mud pump. At this time, the four equipment actions of auger rotation, high-pressure water flushing, mud pump conveying, and auger horizontal movement are carried out simultaneously. ③Shift: Keep the three actions of reamer rotation, high-pressure water flushing and mud pumping running continuously, and control the crawler to make the whole vehicle move forward; at this time, the four actions of reamer rotation, high-pressure water flushing, mud pumping and crawler movement are performed simultaneously; ④Completion: Repeat the above operation process to complete the dredging of the next section.

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