USV full-speed rotary column stabilization control optimization method with energy self-adaptive adjustment

Abstract

The invention provides a USV full-speed rotary column stabilization control optimization method with self-adaptive energy adjustment aiming at the problem of high energy consumption at the full speed of a USV. The method comprises the following steps: firstly, establishing a rotary column lift force model and a USV nonlinear rolling model; secondly, an expected moment is calculated according to a PD controller; then, designing a navigational speed adaptive energy optimization strategy: in a low navigational speed stage, increasing a swing speed factor and a swing angle factor to compensate relative speed insufficiency, and introducing rolling angle normalization processing to reduce redundant energy consumption; in the medium navigational speed stage, the relation between the rotating speed and the swing speed is dynamically balanced through the expected moment, and energy loss caused by eddy current falling is restrained; in the high-speed stage, speed quadratic term factors are adopted to strengthen rotating speed response, the dynamic swing angle complies with the flow direction to reduce resistance, and mechanical swing power consumption is eliminated; and finally, calculating the rolling angle and the energy consumption after energy optimization. According to the method, full-speed energy consumption self-adaptive optimization is realized, the instantaneous energy consumption is remarkably reduced while the stabilization performance is maintained, and the cruising ability of the ship is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of unmanned system motion control technology, in particular to the USV roll reduction control technology suitable for full-speed operation, and more particularly to an energy self-adaptive adjustment USV full-speed spin column roll reduction control optimization method. BACKGROUND

[0002] With the vigorous development of ocean development, the operation capability of intelligent unmanned systems in the marine environment has become a key supporting technology. As the core carrier of marine unmanned systems, unmanned surface vehicles (USVs) are increasingly widely used in fields such as ocean monitoring, search and rescue, and surveying and mapping that rely on accurate hydrological data collection. When USVs navigate in complex hydrological environments, the roll motion caused by sea wave disturbance not only reduces their navigation stability and equipment operation accuracy, but also may cause autonomous decision-making failure or even capsizing risk, which poses a serious challenge to the reliability and endurance of unmanned systems.

[0003] As a key link of USV equipment and systems, efficient roll reduction control technology needs to be combined with artificial intelligence optimization operation system to achieve dynamic adjustment. Through real-time analysis of hydrological parameters, roll state and other data by the artificial intelligence optimization operation system, the roll reduction strategy under different speeds can be accurately adapted, the collaborative efficiency of equipment and systems can be improved, and thus the operation reliability of USVs in complex marine environments can be ensured, so it has become a key breakthrough point for USV research and development.

[0004] Spin column stabilizers achieve roll reduction based on the Magnus effect, and have become an important means of USV roll reduction due to their rapid response and compact structure. However, the existing spin column roll reduction control method has obvious limitations: first, the full-speed adaptability is insufficient, traditional methods mostly rely on a single rotation mode, and at low speed, the insufficient lift due to small relative speed leads to poor roll reduction effect; second, the energy consumption problem is prominent, and the control strategy is not optimized for different speed hydrodynamic characteristics, so fixed parameters are used regardless of high or low speed, resulting in energy waste and seriously restricting the endurance of USVs.

[0005] In view of the above, the present application aims to provide an energy self-adaptive adjustment USV full-speed spin column roll reduction control optimization method, which introduces a rotation-swing compound mode and designs energy optimization strategies by speed, to achieve effective roll reduction of USVs in the full-speed range, while significantly reducing energy consumption and improving their navigation stability and endurance.

[0006] In the paper "Simulation and analysis of Magnus rotating roll stabilizer at low speed", a PID controller is used to achieve roll reduction at low speed, and the hydrodynamic characteristics of the Magnus rotating wing are verified by CFD simulation. Although the effectiveness of roll reduction at low speed is confirmed, there are the following limitations: (1) The control strategy is single, only fixed parameter PID controller is used, and the control parameters are not adjusted dynamically according to the speed, and the roll reduction effect decreases significantly at high speed; (2) Energy optimization strategy is lacking: lack of energy optimization strategy for rotating column speed, swing speed and swing angle at low speed.

[0007] In the patent CN119535970A "USV rotating column roll reduction control system considering complex disturbance and motor dynamic characteristics", a Backstepping controller based on disturbance observer eliminating differential term and an MPC controller based on servo motor state feedback are proposed, which realize roll angle control and energy reduction through inner and outer loop cooperation; Although it performs well in disturbance compensation and motor dynamic optimization, there may be the following problems: (1) Speed adaptability limitation: the control strategy is not designed differently according to the speed, and at low speed, it depends on the high speed response of the servo motor, while at high speed, it does not explain how to solve the problem of dramatic increase of rotating column resistance, which may lead to energy imbalance at all speeds; (2) Energy optimization singularity: energy control only realizes control allocation optimization through MPC weight matrix, without establishing power component model of rotation, swing and angle adjustment, which cannot finely balance the relationship between roll reduction effect and energy consumption.

[0008] In the paper "Design and control characteristics of Magnus rotating roll stabilizer", the hydrodynamic characteristics and low speed roll reduction control of Magnus rotating roll stabilizer are focused on, the lift and drag characteristics are analyzed by CFD numerical simulation, the mathematical model is established, and the roll reduction effect is verified by PID controller; Although it is confirmed that there is obvious roll reduction effect at low speed, there are the following shortcomings: (1) Full speed strategy is lacking: control is limited to low speed, and swing stop strategy is not involved in medium and high speed speed, which leads to dramatic increase of resistance when speed is greater than 9kn; (2) Lack of energy optimization strategy: the paper does not explicitly mention energy optimization strategy, and there should be specific energy saving measures at each speed section. SUMMARY

[0009] To solve the problems of high energy consumption of the rotating column in the USV roll reduction process and insufficient roll reduction effect and energy optimization at different speeds, the application provides an energy self-adaptive adjustment USV full-speed rotating column roll reduction control optimization method, and particularly proposes an energy optimization strategy in different speed sections, aiming to solve the problem that the traditional method is difficult to balance roll reduction and energy consumption in the full-speed range. The core idea of the method is to establish a lift model and a nonlinear roll model based on the Magnus effect, extend the rotating-swing mode to the full speed, divide it into low, medium and high speed sections according to 6kn and 15kn, calculate the expected moment through PD control, and design different optimization strategies for different speeds: at low speed, the lift is enhanced by adjusting the swing angle, swing speed and rotation speed factor; at medium speed, the rotating and swinging relationship is balanced; at high speed, the swing is stopped to reduce the resistance, and an energy consumption model containing rotation, swing and angle adjustment power is established. Through the dynamic adaptation of the control strategy of the speed, the roll reduction effect is improved and the energy consumption is significantly reduced at full speed.

[0010] To achieve the above object, the application adopts the following specific technical solutions to solve it:

[0011] S1: a rotating column stabilizer lift model USV nonlinear roll model based on the Magnus effect is established, and a total roll reduction moment formula is derived;

[0012] S2: a full-speed roll reduction control algorithm is designed, the rotating-swing mode is extended to the full speed, divided into low, medium and high speed sections according to 6kn and 15kn, and a PD control law is designed to generate an expected moment;

[0013] S3: the energy optimization strategy is designed according to the speed section: at low speed, the parameters are adjusted by factors such as swing angle and swing speed; at medium speed, the rotating and swinging relationship is balanced; at high speed, the rotation speed is increased and the swing is stopped to reduce the resistance;

[0014] S4: an energy consumption calculation model containing rotation, swing and angle adjustment power is established, the roll angle and energy consumption after control are calculated by substituting the rotating column roll reduction parameters, and if the current time is less than the control time, S2 is returned to continue control.

[0015] The technical scheme of the method has the following characteristics:

[0016] S1 specifically includes the following steps:

[0017] S11: according to the Kutta-Joukowski theorem, the Magnus effect force F of the rotating column stabilizer in water under ideal conditions is:

[0018] F=4ρπ 2 r 2 lvn (33)

[0019] Wherein: p is the fluid density, r is the radius of the spin column stabilizer, l is the length of the spin column stabilizer, v is the incoming flow velocity, and n is the rotation speed of the spin column stabilizer;

[0020] S12: set the swing angle θ(t) of the spin column stabilizer as:

[0021]

[0022] Wherein: ω0 is the swing angular velocity of the spin column, τ is the swing limiting parameter and is related to the limited angle of the spin column, T is the swing period, t is the time, and β is the initial swing angle of the spin column;

[0023] S13: the theoretical lift calculation formula of the stabilizer is obtained as:

[0024]

[0025] Wherein: ω0 is the swing angular velocity of the spin column, and L is the span length of the spin column;

[0026] S14: the total roll-reducing torque actually generated by the two pairs of spin column stabilizers is:

[0027]

[0028] Wherein: K i is the roll-reducing torque generated by the i-th spin column stabilizer, F i is the lift generated by the i-th spin column stabilizer, r rw is the roll-reducing force arm of the spin column stabilizer;

[0029] S15: combined with formula (36), the nonlinear roll model of the USV is obtained as:

[0030]

[0031] Wherein: I x and ΔI x are the moment of inertia and additional inertia of the USV, φ is the roll angle, is the roll angular velocity, is the roll angular acceleration, B1, B2, C1, C2, and C3 are hull-related parameters, D is the displacement, h is the transverse metacentric height of the USV, and α f is the effective wave inclination angle.

[0032] S2 specifically comprises the following steps:

[0033] S21: the sailing speed is divided into three stages of low sailing speed, medium sailing speed, and high sailing speed, and the sailing speed segmentation is shown as follows:

[0034]

[0035] In the formula: step_1 is a low speed stage, step_2 is a medium speed stage, step_3 is a high speed stage, and v is the current speed;

[0036] S22: The wave force moment of the sine wave is taken as the disturbance moment of the USV, and the wave disturbance moment is expressed as follows:

[0037] wave_force = wave_amplitude*sin(wave_frequency*t) (39)

[0038] In the formula: wave_amplitude is the amplitude of the disturbance moment, and wave_frequency is the wave frequency;

[0039] S23: Initialize the ship state, set the total simulation time t1, and control the start time t2; before the control start time, let K c = 0, and calculate the roll angle of the USV under the action of the disturbance moment by formula (37);

[0040] S24: After the control time starts, according to the control law design, set the desired roll angle φ kd , and design the PD control law as follows:

[0041] e k =φ k -φ kd (40)

[0042] In the formula: e k is the roll angle error, is the derivative of the roll angle error, and M_desired is the desired control moment;

[0043] S25: In view of the high energy consumption problem of the fin stabilizer, after the PD controller outputs the desired moment, a differentiated optimization strategy is implemented according to the speed segmentation: the S31 strategy is used at low speed, the S32 strategy is used at medium speed, and the S33 strategy is used at high speed.

[0044] S3 specifically includes the following steps:

[0045] S31: Energy optimization strategy design at low speed;

[0046] At low speed, due to the low relative speed, it cannot generate enough lift to resist the disturbance moment, so it is necessary to increase the swing speed and swing angle of the fin to generate a larger relative speed and thus generate a larger resisting moment to offset the roll; at the same time, due to the different effects of different speeds on the fin, the swing angle factor, swing speed factor, rotation speed factor and speed factor are designed as follows at low speed:

[0047] angle_factor = min(1, (a1 + (1 - a1)(φ k / typical_angle)) (42)

[0048] wherein a1 is an angle influence coefficient at low speed, typical_angle is a typical large roll threshold, φ k is a roll angle;

[0049] Since a large swing angle is needed at low speed, a1 is selected in the range of [0.7, 0.75]; by introducing the typical large roll threshold for normalization, the swing speed can be maintained to resist roll, and the swing speed can also be appropriately reduced to reduce energy consumption;

[0050] sway_factor = min(1, (b1 + (1 - b1)(φ k / typical_angle)) (43)

[0051] wherein b1 is a sway influence coefficient at low speed;

[0052] Sway speed is the most important factor affecting the lift of the rotating column at low speed; the sway speed is selected to be larger than the angle, so b1 is selected in the range of [0.8, 0.9]; by introducing the typical large roll threshold for normalization, the sway speed can be maintained to resist roll, and the sway speed can also be appropriately reduced to reduce energy consumption;

[0053] rpm_factor = max(c1, (1 - c1)(φ k / typical_angle)) (44)

[0054] wherein c1 is a rotation speed influence coefficient at low speed;

[0055] At low speed, the rotation speed is smaller than the sway speed and the angle in reducing roll; the rotation speed factor is designed to be small at low speed, but in order to maintain the basic rotation speed to resist roll, one of the two small terms is selected to maintain the rotation speed;

[0056] speed_factor = 1 + d1v (45)

[0057] wherein v is the current speed, and d1 is a low speed influence coefficient;

[0058] After the swing angle factor, the sway factor, the rotation speed factor and the speed factor are established, they are multiplied by the swing angle, the sway speed and the rotation speed, and finally the swing angle, the sway speed and the rotation speed at low speed are designed as follows:

[0059] angle = min(max_angle, pre_angle * angle_factor * speed_factor) (46)

[0060] sway = min(max_sway, pre_sway * sway_factor * speed_factor) (47)

[0061] rpm = min(max_rpm, pre_rpm * rpm_factor * speed_factor) (48)

[0062] wherein max_angle is a maximum angle limit, max_sway is a maximum sway limit, max_rpm is a maximum rpm limit, pre_angle is a current angle, pre_sway is a current sway, pre_rpm is a current rpm;

[0063] After the energy optimization strategy at low speed is executed, step S4 is continued to be executed;

[0064] S32: Energy optimization strategy design at medium speed;

[0065] Since the sway and the angle at medium speed are not the main factors affecting the generated resistance moment, the efficiency of the lift generated by rotation is higher than that of the vortex shedding when the swing is in motion. However, the speed at medium speed cannot completely separate from the swing to generate relative speed, so the focus of the control at medium speed is focused on balancing the relationship between rotation and swing. Based on this, the sway factor, the angle factor, the rpm factor and the speed factor at medium speed are designed as follows:

[0066] sway_fator = min(1, abs(M_desired / Single_column)) (49)

[0067] wherein M_desired is the desired moment generated by the PD controller, and Single_column is the maximum moment generated by a single rotating column;

[0068] At medium speed, compared with the large sway at low speed, the relative size of the sway factor controlled by the expected moment calculated by the PD controller; both can better respond to the rolling situation, and can also reduce the sway of the rotating column as much as possible to balance the relationship between the rotation speed and the sway;

[0069] angle_fator = max(b2, (1-b2) sway_factor) (50)

[0070] Wherein: b2 is an angle adjustment parameter, sway_factor is a sway influence factor;

[0071] For the swing angle of the rotating column, the vortex shedding caused by the swing at medium speed has gradually shown its influence on the lift of the rotating column; Therefore, the influence of the swing factor on the angle is fully considered in the formula, so as to better coordinate the relationship between rotation and swing;

[0072] rpm_factor = min(1, abs(M_desired / Single_column)) (51)

[0073] Wherein: M_desired is the desired moment generated by the PD controller, Single_column is the maximum moment generated by the single rotating column;

[0074] Compared with low speed, the rotation of the rotating column has a more obvious influence on the lift fluctuation of the rotating column, and the desired moment based on the PD controller is used to increase the rotation speed; Both can adjust the rotation speed to maintain the effect of reducing the rolling angle, and can also reduce energy consumption by selecting the relative minimum value of the two numbers;

[0075] speed_factor = 1 + d2v (52)

[0076] Wherein: v is the current speed, d2 is the medium speed influence coefficient;

[0077] After the establishment of the swing angle factor, the swing speed factor, the rotation speed factor and the speed factor, multiply them by the swing angle, the swing speed and the rotation speed, and finally the swing angle, the swing speed and the rotation speed at medium speed are designed as follows:

[0078] sway = min(max_sway, pre_angle*sway_factor*speed_factor) (53)

[0079] angle = min(max_angle, pre_sway*angle_factor*speed_factor) (54)

[0080] rpm = min(max_rpm, pre_rpm + rpm_factor*m*speed_factor) (55)

[0081] Wherein: m is a compensation rotation speed factor;

[0082] After the energy optimization strategy at medium speed is executed, step S4 is continued;

[0083] S33: Energy optimization strategy design at high speed;

[0084] At high speed, the relative velocity between the rotating column and the sea wave is enough, so the control focus of the current stage should be focused on improving the rotating speed, stopping the swing of the rotating column, fixing the angle of the rotating column to adapt to the direction of the USV to reduce resistance; the speed factor, the rotating speed factor, the rotating speed, the swing speed and the swing angle are designed as follows at high speed:

[0085] speed_factor = 1 + d3v 2 (56)

[0086] In the formula: v is the current speed, d3 is the high speed influence coefficient;

[0087] At high speed, the influence of speed on lift is more obvious, so the quadratic term of speed is introduced to better match the nonlinear growth characteristics of resistance with speed;

[0088] rpm_factor = min(1, a3*abs(M_desired / Single_column)) (57)

[0089] In the formula: a3 is the rotating speed gain coefficient at high speed;

[0090] The rotating speed of the rotating column is adjusted with the change of the desired torque, and the rotating speed gain coefficient is introduced to increase the rotating speed of the rotating column;

[0091] rpm = n + rpm_factor*pre_rpm*speed_facor (58)

[0092] In the formula: n is the rotating speed compensation factor;

[0093] sway = 0 (59)

[0094] At high speed, the rotating speed is the most critical factor for generating lift, and the rotating speed compensation factor is introduced to better generate lift when the swing speed is 0;

[0095] angle = min(max_angle, pri_angle*speed_factor) (60)

[0096] In the formula: pri_angle is the fixed initial swing angle at high speed;

[0097] The initial swing angle is fixed, and the speed factor is introduced to better make the direction of the rotating column better adapt to the direction of the sea wave to reduce resistance;

[0098] After executing the energy optimization strategy at high speed, step S4 is continued.

[0099] S4 specifically includes the following steps:

[0100] S41: The energy consumption calculation is divided into three parts of rotating power component, swinging power component and angle adjustment power, which are as follows:

[0101] power_rotation=a*(rpm / d) 3 (61)

[0102] power_sway=b*sway 2 (62)

[0103] power_angle=c*abs(angle) (63)

[0104] In the formula: a is the rotating power coefficient, b is the swinging power coefficient, c is the angle adjustment power coefficient, and d is the speed reference coefficient;

[0105] S42: The energy consumption characteristics of the rotating column are quantitatively characterized by the power parameter; according to formulas (39), (40) and (41), the total power calculation formula is as follows:

[0106] power=(power_rotation+power_sway+power_angle)*cyl_num (64)

[0107] In the formula: cyl_num is the total number of rotating columns;

[0108] S43: The specific parameters of the actuator are brought into formula (64), so that the energy consumption after control can be obtained; the specific parameters of the actuator are brought into formula (35) and combined with formula (37), so that the roll angle after control can be calculated;

[0109] S44: If the current time is less than the control time, step 2 is continued.

[0110] The present application has the following beneficial effects:

[0111] 1. The present application enhances the relative flow velocity of the rotating column and the water flow and improves the lift generation efficiency by designing the swing angle factor and the swing speed factor, combining with the typical large roll threshold normalization processing in the low speed section; in terms of energy consumption optimization, the low energy consumption swing angle adjustment strategy is preferred, and the swing speed is dynamically adjusted through the swing speed factor to reduce the redundant energy consumption. Experiments show that the roll reduction effect in the low speed section is improved by 7.7% compared with the traditional PD control, and the instantaneous energy consumption is reduced by 43.1%.

[0112] 2. This patent takes the PD controller expected torque as the benchmark in the medium speed range, designs a dynamic balance mechanism for swing speed, swing angle and rotation speed, suppresses redundant swing through swing speed factor, strengthens rotational lift through rotation speed factor, and weakens swing angle to reduce eddy current loss; optimally matches torque demand and actuator parameters to avoid double high energy consumption of rotation and swing. Experiments show that the roll reduction effect in the medium speed range is improved by 13.5% compared with the traditional PD control, and the instantaneous energy consumption is reduced by 41.2%.

[0113] 3. This patent adopts the strategy of fixing the swing angle and stopping the swing in the high speed range, strengthens the rotation speed response through the square term of the speed factor to utilize the Magnus effect to dominate the lift, and fixes the swing angle to reduce the wave making resistance in the direction of the flow; the energy consumption is avoided by the swing mechanism. Experiments show that the roll reduction effect in the high speed range is improved by 28.2% compared with the traditional PD control, and the instantaneous energy consumption is reduced by 37.9%. BRIEF DESCRIPTION OF DRAWINGS

[0114] Figure 1 is a general technical flowchart;

[0115] Figure 2 is a schematic diagram of the Magnus effect;

[0116] Figure 3 is a schematic diagram of a ship roll model with two pairs of spin column stabilizers;

[0117] Figure 4 is a comparison chart of roll reduction at low speed;

[0118] Figure 5 is a comparison chart of instantaneous energy consumption at low speed;

[0119] Figure 6 is a comparison chart of roll reduction at medium speed;

[0120] Figure 7 is a comparison chart of instantaneous energy consumption at medium speed;

[0121] Figure 8 is a comparison chart of roll reduction at high speed;

[0122] Figure 9 is a comparison chart of instantaneous energy consumption at high speed. DETAILED DESCRIPTION

[0123] To make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, an energy self-adaptive adjustment USV full-speed spin column roll reduction control optimization method is designed as follows, and its flowchart is shown in Figure 1 The method comprises the following steps:

[0124] S1: Establish a spin column stabilizer lift model based on the Magnus effect and a USV nonlinear roll model, and derive a total roll reduction torque formula, the process is as follows:

[0125] S11: The rotating column stabilizer is installed on the two sides of the ship body as a cylindrical rotor wing. Its working principle is based on the Magnus effect, as shown in Figure 2 According to the Kutta-Joukowski theorem, the Magnus effect force F that the rotating column stabilizer receives in the water under ideal conditions is:

[0126] F = 4prrlvn (65) 2 r 2 lvn (65)

[0127] In the formula: p is the fluid density, r is the radius of the rotating column stabilizer, l is the length of the rotating column stabilizer, v is the incoming flow velocity, and n is the rotating speed of the rotating column stabilizer;

[0128] S12: The swing angle θ (t) of the rotating column stabilizer is set as:

[0129]

[0130] In the formula: ω0 is the swing angular velocity of the rotating column, τ is the swing limiting parameter and is related to the limited angle of the rotating column, T is the swing period, t is the time, and β is the initial swing angle of the rotating column;

[0131] S13: The theoretical lift calculation formula of the stabilizer is obtained as:

[0132]

[0133] In the formula: ω0 is the swing angular velocity of the rotating column, and L is the span length of the rotating column;

[0134] S14: A USV is sailing in a fixed direction, and two pairs of rotating column stabilizers are symmetrically installed on the two sides of the ship body. The roll direction of the ship body is as shown in Figure 3 The sailing speed v is the relative incoming flow velocity of the USV and the sea water, and F i is the lift generated by the i-th rotating column stabilizer. Therefore, the total roll reduction moment actually generated by the two pairs of rotating column stabilizers is:

[0135]

[0136] In the formula: K i is the roll reduction moment generated by the i-th rotating column stabilizer, F i is the lift generated by the i-th rotating column stabilizer, r rw is the roll reduction arm of the rotating column stabilizer;

[0137] S15: Combined with formula (68), the nonlinear roll model of the USV is obtained as:

[0138]

[0139] where I x and ΔI x is the moment of inertia of the USV and the added mass, φ is the roll angle, is the roll angular velocity, is the roll angular acceleration, B1, B2, C2, C3 are hull related parameters, D is the displacement, h is the roll metacentric height of the USV, α f is the effective wave inclination.

[0140] S2: Design the roll reduction control algorithm at full speed, extend the roll- pitch mode to full speed, divide it into low, medium and high speed sections according to 6kn and 15kn, and design the PD control law to generate the expected moment, which includes the following sub-steps:

[0141] S21: Divide the speed into low, medium and high speed stages, and the speed segmentation is as follows:

[0142]

[0143] where step_1 is the low speed stage, step_2 is the medium speed stage, step_3 is the high speed stage, and v is the current speed;

[0144] S22: For the convenience of observing the roll reduction effect and simplifying the calculation, the sine wave is used as the disturbance of the ship, and the wave moment of the sine wave is used as the disturbance moment of the USV, and the wave disturbance moment is expressed as follows:

[0145] wave_force = wave_amplitude*sin(wave_frequency*t) (71)

[0146] where wave_amplitude is the amplitude of the disturbance moment, and wave_frequency is the wave frequency;

[0147] S23: Initialize the ship state, set the total simulation time t1, and set the control start time t2; before the control start time, let K c = 0, calculate the roll angle of the USV only under the disturbance moment by equation (69);

[0148] S24: After the control time starts, according to the control law design, set the expected roll angle φ kd , and design the PD control law as follows:

[0149] e k = φ k -φ kd (72)

[0150]

[0151] wherein: e k is the roll angle error, is the roll angle error derivative, and M_desired is the desired control moment;

[0152] S25: In view of the high energy consumption problem of the rotating column roll stabilization, after the PD controller outputs the desired moment, a differentiated optimization strategy is implemented according to the speed segmentation: the S31 strategy is adopted at low speed, the S32 strategy is adopted at medium speed, and the S33 strategy is adopted at high speed.

[0153] S3: Energy optimization strategies are designed according to the speed segmentation: at low speed, the parameters are adjusted by factors such as swing angle and swing speed; at medium speed, the relationship between rotation and swing is balanced; at high speed, the rotation speed is increased and the swing is stopped to reduce resistance;

[0154] S31: Energy optimization strategy design at low speed;

[0155] At low speed, because the relative speed is too low, it cannot generate enough lift to resist the disturbance moment, so it is necessary to increase the swing speed and swing angle of the rotating column to generate greater resistance moment to offset the roll; at the same time, because different speeds have different effects on the rotating column; therefore, at low speed, the swing angle factor, swing speed factor, rotation speed factor and speed factor are designed as follows:

[0156] angle_fator=min(1,(a1+(1-a1)(φ k / typical_angle)) (74)

[0157] wherein: a1 is the angle influence coefficient at low speed, typical_angle is the typical large roll threshold, and φ k is the roll angle;

[0158] Because a large swing angle is needed at low speed, the value of a1 is taken in the range of [0.7, 0.75]; by introducing the typical large roll threshold, normalization processing is carried out, which can not only maintain a large swing speed to resist roll, but also appropriately reduce the swing speed to reduce part of the energy consumption;

[0159] sway_fator=min(1,(b1+(1-b1)(φ k / typical_angle)) (75)

[0160] wherein: b1 is the swing speed influence coefficient at low speed, and φ

[0161] The swing speed is the most important factor that restricts the lift of the rotating column at low speed. The swing speed is selected to be larger than the angle, and thus the value of b1 is selected in the range of [0.8, 0.9]. The typical large roll threshold is introduced for normalization, so that the large swing speed can resist the roll, and the swing speed can be appropriately reduced to reduce energy consumption.

[0162] rpm_factor = max(c1, (1-c1)(φ k / typical_angle)) (76)

[0163] In the formula, c1 is the rotation speed influence coefficient at low speed.

[0164] At low speed, the rotation speed is smaller than the swing speed and the swing angle in terms of the roll reduction effect. The rotation speed factor is designed to be small at low speed, but in order to maintain the basic rotation speed to resist the roll, one of the two small terms is selected to maintain the rotation speed.

[0165] speed_factor = 1+d1v (77)

[0166] In the formula: v is the current speed, and d1 is the low speed influence coefficient.

[0167] After the swing angle factor, the swing speed factor, the rotation speed factor and the speed factor are established, they are multiplied by the swing angle, the swing speed and the rotation speed, and finally the swing angle, the swing speed and the rotation speed at low speed are designed as follows:

[0168] angle = min(max_angle, pre_angle*angle_factor*speed_factor) (78)

[0169] sway = min(max_sway, pre_sway*sway_factor*speed_factor) (79)

[0170] rpm = min(max_rpm, pre_rpm*rpm_factor*speed_factor) (80)

[0171] In the formula: max_angle is the maximum angle limit, max_sway is the maximum swing speed limit, max_rpm is the maximum rotation speed limit, pre_angle is the current angle, pre_sway is the current swing speed, and pre_rpm is the current rotation speed.

[0172] After the energy optimization strategy at low speed is executed, step S4 is continued to be executed.

[0173] S32: Energy optimization strategy design at medium speed.

[0174] Since the swing speed and the swing angle under the medium speed are not the main factors affecting the generation of the resistance moment, the efficiency of the lift generated by rotation is higher relative to the vortex shedding of the swing in motion; However, the speed of the medium speed cannot completely separate from the swing to generate relative speed, so the focus of control under the medium speed is on balancing the relationship between rotation and swing; Based on this, the swing speed factor, the swing angle factor, the rotation speed factor and the speed factor are designed under the medium speed as follows:

[0175] sway_fator=min(1,abs(M_desired / Single_column)) (81)

[0176] In the formula: M_desired is the expected moment generated by the PD controller, Single_column is the maximum moment generated by a single rotating column;

[0177] Under the medium speed, compared with the large swing speed under the low speed, the relative size of the swing speed factor controlled by the expected moment calculated by the PD controller; It can better respond to the rolling situation, and it can also reduce the swing speed of the rotating column as much as possible to balance the relationship between rotation speed and swing speed;

[0178] angle_fator=max(b2,(1-b2)*sway_factor) (82)

[0179] In the formula: b2 is the angle adjustment parameter, and sway_factor is the swing speed influence factor;

[0180] For the swing angle of the rotating column, the vortex shedding caused by the swing under the medium speed has gradually appeared on the lift of the rotating column; Therefore, the influence of the swing factor on the angle is fully considered in the formula, so as to better coordinate the relationship between rotation and swing;

[0181] rpm_factor=min(1,abs(M_desired / Single_column)) (83)

[0182] In the formula: M_desired is the expected moment generated by the PD controller, Single_column is the maximum moment generated by a single rotating column;

[0183] Compared with low speed, the rotation of the rotating column is more obvious for the lift fluctuation of the rotating column, and the expected moment based on the PD controller is used to improve the rotation speed; It can adjust the rotation speed with the rolling angle to maintain the anti-rolling effect, and it can also reduce energy consumption by selecting the relative minimum value of the two numbers;

[0184] speed_factor=1+d2v (84)

[0185] wherein v is the current speed, and d2 is the medium speed influence coefficient;

[0186] After the establishment of the swing angle factor, swing speed factor, rotation speed factor and speed factor, they are multiplied by the swing angle, swing speed and rotation speed. The final swing angle, swing speed and rotation speed design under medium speed are as follows:

[0187] sway = min(max_sway, pre_angle * sway_factor * speed_factor) (85)

[0188] angle = min(max_angle, pre_sway * angle_factor * speed_factor) (86)

[0189] rpm = min(max_rpm, pre_rpm + rpm_factor * m * speed_factor) (87)

[0190] wherein m is the compensation rotation speed factor;

[0191] After the energy optimization strategy under medium speed is executed, step S4 is continued to be executed;

[0192] S33: Energy optimization strategy design under high speed;

[0193] Under high speed, the relative speed between the rotating column and the sea wave is sufficient, so the control focus of the current stage should be focused on improving the rotation speed, stopping the swing of the rotating column, and fixing the angle of the rotating column to conform to the USV travel direction to reduce resistance; The speed factor, rotation speed factor, rotation speed, swing speed and swing angle design under high speed are as follows:

[0194] speed_factor = 1 + d3v 2 (88)

[0195] wherein v is the current speed, and d3 is the high speed influence coefficient;

[0196] Under high speed, the speed has a more obvious influence on the lift, so the quadratic term of the speed is introduced to better match the nonlinear growth characteristics of the resistance with the speed;

[0197] rpm_factor = min(1, a3 * abs(M_desired / Single_column)) (89)

[0198] wherein a3 is the rotation speed gain coefficient under high speed;

[0199] With the change of the desired torque to adjust the rotation speed of the column, the rotation speed gain factor is introduced to increase the rotation speed of the column;

[0200] rpm = n + rpm_factor * pre_rpm * speed_facor (90)

[0201] In the formula: n is the compensation rotation speed factor;

[0202] Sway = 0 (91)

[0203] At high speed, the rotation speed is the most critical factor for generating lift, and in the case of sway speed = 0, the rotation speed compensation factor is introduced to better generate lift;

[0204] Angle = min(max_angle, pri_angle * speed_factor) (92)

[0205] In the formula: pri_angle is the fixed initial swing angle at high speed;

[0206] The fixed initial swing angle is introduced to better make the column direction better meet the sea wave direction and reduce resistance;

[0207] After the energy optimization strategy at high speed is executed, step S4 is continued.

[0208] S4: Establish an energy consumption calculation model containing rotation, swing, and angle adjustment power, substitute the roll angle and energy consumption calculated by the column roll reduction parameter control, and if the current time is less than the control time, return to S2 to continue control;

[0209] S41: The energy consumption calculation is divided into rotation power component, swing power component and angle adjustment power three parts, as follows:

[0210] power_rotation = a * (rpm / d) 3 (93)

[0211] power_sway = b * sway 2 (94)

[0212] power_angle = c * abs(angle) (95)

[0213] In the formula: a is the rotation power coefficient, b is the swing power coefficient, c is the angle adjustment power coefficient, and d is the rotation speed reference coefficient;

[0214] S42: The energy consumption characteristics of the column are quantitatively represented by the power parameters; according to formulas (39), (40) and (41), the total power calculation formula is as follows:

[0215] power = (power_rotation + power_sway + power_angle) * cyl_num (96)

[0216] In the formula: cyl_num is the total number of rotating columns;

[0217] S43: The specific parameters of the actuator are brought into formula (96) to obtain the energy consumption after control; the specific parameters of the actuator are brought into formula (67) and combined with formula (69) to calculate the roll angle after control;

[0218] S44: If the current time is less than the control time, continue to perform step 2.

[0219] In this way, under the action of the above-mentioned PD control method combined with the energy optimization strategy, the roll of the USV can be reduced, and the energy consumption of the USV during navigation can also be reduced. The functions of roll reduction and energy consumption reduction of the USV at full speed are realized. In order to embody the beneficial effects of the present patent, under the action of sinusoidal disturbance, the roll reduction effect and instantaneous energy consumption at different speeds are simulated to verify the beneficial effects.

[0220] Figure 4 The roll reduction comparison simulation results under the action of sinusoidal superimposed wave disturbance at low speed are shown. It can be seen that, compared with the traditional PD control method which controls the roll angle within ±7.9 deg, the control method designed in the present patent can control the roll angle within ±5.91 deg, which improves the roll reduction effect by 7.7% and improves the stability of the system.

[0221] Figure 5 The instantaneous energy consumption comparison simulation results under the action of sinusoidal wave disturbance at low speed are shown. It can be seen that, compared with the traditional PD control method, the control method designed in the present patent can reduce the instantaneous energy consumption by 43.1% at low speed compared with the traditional control method, which improves the endurance of the USV at low speed.

[0222] Figure 6 The roll reduction comparison simulation results under the action of sinusoidal superimposed wave disturbance at medium speed are shown. It can be seen that, compared with the traditional PD control method which controls the roll angle within ±7.35 deg, the control method designed in the present patent can control the roll angle within ±5.44 deg, which improves the roll reduction effect by 13.5% and improves the stability of the system.

[0223] Figure 7 The instantaneous energy consumption comparison simulation results under the action of sinusoidal wave disturbance at medium speed are shown. It can be seen that, compared with the traditional PD control method, the control method designed in the present patent can reduce the instantaneous energy consumption by 41.2% at low speed compared with the traditional control method.

[0224] Figure 8 The roll reduction simulation results under high speed sinusoidal wave disturbance are shown. It can be seen that compared with the traditional PD control method which controls the roll angle within ±7.92 deg, the control method of the patent can control the roll angle within ±3.92 deg, which improves the roll reduction efficiency by 28.2% and improves the stability of the system.

[0225] Figure 9 The instantaneous energy consumption simulation results under high speed sinusoidal wave disturbance are shown. It can be seen that compared with the traditional PD control method, the control method of the patent can reduce the instantaneous energy consumption by 37.9% at low speed compared with the traditional control method.

[0226] In summary, the control method has slightly improved roll reduction effect compared with the traditional control method, but has obvious optimization in energy consumption, especially in medium and high speed. Under the control strategy of the patent, for the USV running at full speed, the roll reduction effect is improved compared with the traditional method, and the energy consumption is obviously reduced in terms of instantaneous energy consumption, which greatly improves the endurance of the USV at different speeds.

[0227] The above specific embodiments further illustrate the purposes, technical solutions and advantages of the present application. The above examples are only used to illustrate the technical solutions of the present application, and are not intended to limit the protection scope of the present application. Those skilled in the art should understand that any modification or equivalent replacement of the technical solutions of the present application is included in the protection scope of the present application.

Claims

1. An energy self-adaptive adjusting USV full-speed fin stabilizer control optimization method, characterized in that, Comprising the following steps: S1: Establishing a Magnus effect-based spin column stabilizer lift model USV nonlinear roll model, and deriving the total roll-reducing torque formula; S11: According to the Kutta-Joukowski theorem, the Magnus effect force F experienced by the spin column stabilizer in water under ideal conditions is: F = 4pπ 2 r 2 lvn (1) Where: ρ is the fluid density, l is the length of the spin column stabilizer, r is the radius of the spin column stabilizer, v is the flow velocity, and n is the spin column stabilizer rotation speed; S12: Set the swing angle θ(t) of the spin column stabilizer as: Where: ω0 is the swing angular velocity of the spin column, τ is the swing limiting parameter and is related to the limited angle of the spin column, T is the swing period, t is the time, and β is the initial swing angle of the spin column; S13: The theoretical lift calculation formula of the stabilizer is obtained as: Where: ω0 is the swing angular velocity of the spin column, and L is the span of the spin column; S14: Total stabilizing moment K actually generated by the two pairs of spin stabilizers c is: where: K i is the righting moment produced by the ith spin fin stabilizer, F i is the lift produced by the ith spin fin stabilizer, r rw is the righting lever of the spin fin stabilizer; S15: Combined with formula (4), the USV nonlinear roll model is obtained as: where I x and ΔI x is the moment of inertia of the USV and the added mass, φ is the roll angle, is the roll angular velocity, is the roll angular acceleration, B1, B2, C1, C2, C3 are hull related parameters, D is the displacement, h is the roll metacentric height of the USV, α f is the effective wave inclination angle; S2: Designing a full-speed roll-reducing control algorithm, expanding the rotation-swing mode to full speed, dividing into low, medium and high speed sections according to 6kn and 15kn, and designing a PD control law to generate the expected torque; S21: Divide the speed into low, medium and high speed stages, and the speed segmentation is as follows: Where: step_1 is the low speed stage, step_2 is the medium speed stage, step_3 is the high speed stage, and v is the current speed; S22: Take the sinusoidal wave force as the disturbance torque of the USV, and the wave disturbance torque is expressed as: wave_force = wave_amplitude*sin(wave_frequency*t) (7) Where: wave_amplitude is the disturbance torque amplitude, and wave_frequency is the wave frequency; S23: initialize the ship state, set the total simulation time t1, control the start time t2; let K c = 0 before the control start time, calculate the roll angle of the USV under the action of the disturbance moment by formula (5); S24: After the control time starts, set the desired roll angle φ according to the control law design kd The PD control law is designed as follows: where: e k is the roll angle error, is the roll angle error derivative, and M_desired is the desired control moment. S25: In view of the high energy consumption problem of the spin column roll-reducing, after the PD controller outputs the expected torque, different optimization strategies are implemented according to the speed segmentation: S31 strategy is adopted for low speed, S32 strategy is adopted for medium speed, and S33 strategy is adopted for high speed; S3: Designing an energy optimization strategy according to the speed segmentation: adjust the parameters such as swing angle and swing speed for low speed; balance the rotation and swing relationship for medium speed; increase the rotation speed and stop the swing to reduce the resistance for high speed; S31: Design of energy optimization strategy for low speed; The swing angle factor, swing speed factor, rotation speed factor and speed factor are designed as follows for low speed: angle_fator = min(l, (a1 + (1 - a1) (φ k / typical_angle)) (10) wherein: a1 is an angle influence coefficient at low speed, typical_angle is a typical large roll threshold, φ k is the roll angle; sway_fator = min(l, (bl + (1 - bl)(φ k / typical_angle)) (11) Where: b1 is the swing speed influence coefficient under low speed; rpm_factor = max(c1, (1 - c1)(φ k / typical_angle)) (12) Where: c1 is the rotation speed influence coefficient under low speed; speed_factor=1+d1v (13) Where: v is the current speed, and d1 is the low speed influence coefficient; The final swing angle, swing speed and rotation speed under low speed are designed as follows: angle=min(max_angle,pre_angle*angle_factor*speed_factor) (14) sway=min(max_sway,pre_sway*sway_factor*speed_factor) (15) rpm = min(max_rpm, pre_rpm * rpm_factor * speed_factor) (16) where max_angle is the maximum angle limit, max_sway is the maximum sway speed limit, max_rpm is the maximum rotation speed limit, pre_angle is the current angle, pre_sway is the current sway speed, pre_rpm is the current rotation speed; After the energy optimization strategy at low speed is executed, step S4 is continued to be executed; S32: Energy optimization strategy design at medium speed; At medium speed, the sway speed factor, the angle factor, the rotation speed factor and the speed factor are designed as follows: sway_factor = min(1, abs(M_desired / Single_column)) (17) where M_desired is the desired torque generated by the PD controller, and Single_column is the maximum torque generated by a single column; angle_factor = max(b2, (1-b2) * sway_factor) (18) where b2 is an angle adjustment parameter, and sway_factor is a sway speed influence factor; rpm_factor = min(1, abs(M_desired / Single_column)) (19) where M_desired is the desired torque generated by the PD controller, and Single_column is the maximum torque generated by a single column; speed_factor = 1 + d2v (20) where v is the current speed, and d2 is a medium speed influence coefficient; Finally, the angle, the sway speed and the rotation speed at medium speed are designed as follows: sway = min(max_sway, pre_angle * sway_factor * speed_factor) (21) angle = min(max_angle, pre_sway * angle_factor * speed_factor) (22) rpm = min(max_rpm, pre_rpm + rpm_factor * m * speed_factor) (23) where m is a rotation speed compensation factor; After the energy optimization strategy at medium speed is executed, step S4 is continued to be executed; S33: Energy optimization strategy design at high speed; At high speed, the speed factor, the rotation speed factor, the rotation speed, the sway speed and the angle are designed as follows: speed_factor = 1 + d3v 2 (24) where v is the current speed, and d3 is a high speed influence coefficient; rpm_factor = min(1, a3 * abs(M_desired / Single_column)) (25) where a3 is a rotation speed gain coefficient at high speed; rpm = n + rpm_factor * pre_rpm * speed_facor (26) where n is a rotation speed compensation factor; sway = 0 (27) angle = min(max_angle, pri_angle * speed_factor) (28) wherein: pri_angle is the fixed initial swing angle at high speed; The fixed initial swing angle is introduced to introduce the speed factor to better make the rotating column direction better match the sea wave direction to reduce the resistance; After the energy optimization strategy at high speed is executed, step S4 is continued to be executed; S4: An energy consumption calculation model containing rotating, swinging, and angle adjustment power is established, and the roll angle and energy consumption after the rotating column roll reduction parameter calculation control are substituted. If the current time is less than the control time, step S2 is returned to continue to control; S41: The energy consumption calculation is divided into three parts: rotating power component, swinging power component, and angle adjustment power. The specific contents are as follows: power_rotation = a * (rpm / d) 3 (29) power_sway = b * sway 2 (30) power_angle = c * abs(angle) (31) wherein: a is the rotating power coefficient, b is the swinging power coefficient, c is the angle adjustment power coefficient, and d is the speed reference coefficient; S42: The energy consumption characteristics of the rotating column are quantitatively represented by the power parameter. According to formulas (29), (30), and (31), the total power calculation formula is as follows: power = (power_rotation + power_sway + power_angle) * cyl_num (32) wherein: cyl_num is the total number of rotating columns; S43: The specific parameters of the actuator are substituted into formula (32), and the energy consumption after control can be obtained. The specific parameters of the actuator are substituted into formula (3) and combined with formula (5), and the roll angle after control can be calculated. S44: If the current time is less than the control time, step 2 is continued to be executed.

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