A ROV depth and attitude decoupling control method based on spatial surface depth

Abstract

The application discloses a ROV depth and attitude decoupling control method based on spatial surface depth. The method comprises the following steps: establishing a depth model of a four-axis vertical propeller unmanned remote control submarine; inputting a centroid depth and an attitude angle, and outputting a vertical propeller depth; establishing a decoupling control model; inputting an actual vertical propeller depth and a target depth, and outputting a vertical propeller input control quantity, so as to realize independent closed-loop control of the vertical propeller. The application converts the coupling control of the depth and the attitude angle of the ROV into independent control of the depth of each vertical propeller of the ROV, effectively reduces the coupling of the control process, guarantees the stability of the control system, reduces the depth and attitude angle tracking error of the ROV, and greatly improves the control performance of the depth and attitude angle of the ROV.

Description

TECHNICAL FIELD

[0001] The application relates to an ROV depth and attitude decoupling control method, relates to the ROV control field, and particularly relates to an ROV depth and attitude decoupling control method based on spatial surface depth. BACKGROUND

[0002] The ROV is widely applied to the exploration and development of the sea due to sufficient power, high efficient information transmission rate and high safety. In order to make the ROV better adapt to the sea operation task, the depth and attitude control precision of the ROV needs to be improved. At present, the depth and attitude control method of the ROV mainly adopts the superposition control idea, that is, three groups of input control quantities are obtained by respectively performing closed loop control operation on the depth, roll angle and pitch angle of the ROV, each group of control quantity covers the control signals of all the propellers, and then the three groups of input control quantities are superposed to control the rotating speed of each propeller. The method is relatively simple and direct, but the control process is strongly coupled, for example, the control of the attitude angle will interfere with the control of the depth, and it is difficult to meet the requirements of the complex and accurate depth and attitude control of the ROV. SUMMARY

[0003] In order to solve the problems in the background art, the application provides an ROV depth and attitude decoupling control method based on spatial surface depth. The application realizes the accurate control of the overall depth and attitude angle of the ROV by adjusting the depth of each vertical propeller of the ROV, and improves the underwater operation ability of the ROV.

[0004] The technical scheme adopted by the application is:

[0005] The ROV depth and attitude decoupling control method based on spatial surface depth provided by the application comprises:

[0006] Step 100: a depth model of a four-axis vertical propeller unmanned remote control submersible (ROV) is established; the actual centroid depth and the actual attitude angle of the ROV are obtained, the actual centroid depth and the actual attitude angle of the ROV are input into the depth model, the depth model outputs the actual depth of each vertical propeller of the ROV; the target centroid depth and the target attitude angle of the ROV are input into the depth model, and the depth model outputs the target depth of each vertical propeller of the ROV.

[0007] Step 200: establishing a decoupling control model of the four-axial vertical propeller unmanned remotely operated vehicle (ROV); inputting actual depth and target depth of each vertical propeller of the unmanned remotely operated vehicle (ROV) into the decoupling control model, and outputting input control quantity of each vertical propeller of the unmanned remotely operated vehicle (ROV) from the decoupling control model, so as to realize independent closed-loop control on each vertical propeller of the unmanned remotely operated vehicle (ROV) respectively.

[0008] In step 1, the depth model of the four-axial vertical propeller unmanned remotely operated vehicle (ROV) is specifically as follows:

[0009] Depth1 = z1 + Depth

[0010] Depth2 = z2 + Depth

[0011] Depth3 = z3 + Depth

[0012] Depth4 = z4 + Depth

[0013] Wherein, Depth1, Depth2, Depth3 and Depth4 respectively represent the depth of the first, second, third and fourth vertical propellers of the unmanned remotely operated vehicle (ROV); z1, z2, z3 and z4 respectively represent the Z-axis coordinates of the first, second, third and fourth vertical propellers of the unmanned remotely operated vehicle (ROV) in the world coordinate system; and Depth represents the centroid depth of the unmanned remotely operated vehicle (ROV).

[0014] The world coordinate system is specifically established with the centroid of the unmanned remotely operated vehicle (ROV) as the coordinate origin, with the projection of the longitudinal axis of the unmanned remotely operated vehicle (ROV) carrier pointing to the head direction in the horizontal plane of the origin as the X-axis, with the vertical downward direction as the Z-axis, and with the Y-axis being perpendicular to the XOZ plane and satisfying the right-hand rule.

[0015] The Z-axis coordinates of the first, second, third and fourth vertical propellers of the unmanned remotely operated vehicle (ROV) in the world coordinate system are specifically as follows:

[0016]

[0017]

[0018]

[0019]

[0020] Wherein, L x , L y and L zRepresent the X0, Y0, and Z0 coordinates of the first vertical propeller of the remotely operated vehicle (ROV) in the carrier coordinate system; ψ and These represent the pitch and roll angles of an unmanned remotely operated vehicle (ROV), which are the attitude angles of the ROV.

[0021] Obtain the attitude angle of the ROV And the centroid depth, where θ is the heading angle and ψ is the pitch angle. The roll angle is given; the carrier coordinates of the first vertical propeller in the first quadrant of the carrier coordinate system are [L]. x L y L z ] T The world coordinates [x1, y1, z1] of vertical propeller 1 are obtained by analyzing the attitude angle. T The details are as follows:

[0022]

[0023] The ROV's vertical propellers are symmetrically distributed. The world coordinates of the second vertical propeller, which is symmetrical to the first vertical propeller about the X-axis, are [x2, y2, z2]. T The world coordinates of the third vertical propeller, which is symmetrical to the first vertical propeller about the Y-axis, are [x3, y3, z3]. T The world coordinates of the fourth vertical propeller, which is symmetrical to the first vertical propeller about the origin, are [x4, y4, z4]. T It satisfies the following relationship:

[0024]

[0025] z3=z1+2L x sin(ψ)

[0026]

[0027] The aforementioned carrier coordinate system is specifically established with the centroid of the ROV as the origin, the longitudinal axis pointing towards the head as the X0 axis, the transverse axis pointing to the right of the head's forward direction as the Y0 axis, and the direction pointing towards the bottom of the carrier as the Z0 axis. The first vertical propeller of the ROV is located in the first quadrant of the carrier coordinate system. The second vertical propeller is symmetrical about the X0 axis, the third vertical propeller is symmetrical about the Y0 axis, and the fourth vertical propeller is symmetrical about the center of the origin of the carrier coordinate system.

[0028] The depth sensor and the electronic compass are mounted at the center of the shell of the unmanned remotely operated vehicle (ROV), the actual centroid depth of the unmanned remotely operated vehicle (ROV) is obtained according to the depth sensor, and the actual attitude angle of the unmanned remotely operated vehicle (ROV) is obtained according to the electronic compass.

[0029] In the step 200, the decoupling control model of the unmanned remotely operated vehicle (ROV) with four vertical propellers is specifically as follows:

[0030] U1(s) = [DEPTH t1 (s) - DEPTH r1 (s)] G1(s)

[0031] U2(s) = [DEPTH t2 (s) - DEPTH r2 (s)] G2(s)

[0032] U3(s) = [DEPTH t3 (s) - DEPTH r3 (s)] G3(s)

[0033] U4(s) = [DEPTH t4 (s) - DEPTH r4 (s)] G4(s)

[0034] wherein U1(s), U2(s), U3(s) and U4(s) represent the input control quantity of the first, second, third and fourth vertical propellers of the unmanned remotely operated vehicle (ROV) in the form of Laplace transform, s represents a complex frequency; DEPTH t1 (s), DEPTH t2 (s), DEPTH t3 (s) and DEPTH t4 (s) represent the target depth of the first, second, third and fourth vertical propellers of the unmanned remotely operated vehicle (ROV) in the form of Laplace transform, DEPTH r1 (s), DEPTH r2 (s), DEPTH r3 (s) and DEPTH r4 (s) represent the actual depth of the first, second, third and fourth vertical propellers of the unmanned remotely operated vehicle (ROV) in the form of Laplace transform, and G1(s), G2(s), G3(s) and G4(s) represent the transfer function of the closed-loop controller of the first, second, third and fourth vertical propellers of the unmanned remotely operated vehicle (ROV), respectively. The closed-loop controller can be specifically a PID controller.

[0035] All vertical propellers of the ROV are closed-loop controlled with the target value of the target depth of the vertical propeller and the actual value of the actual depth of the vertical propeller, so as to obtain the input control quantity of each vertical propeller, and finally make the attitude angle and the centroid depth of the ROV close to and reach the target value.

[0036] The beneficial effects of the present application are:

[0037] The present application converts the coupled control of the depth and the attitude angle of the ROV into the independent control of the depth of each vertical propeller of the ROV, effectively reduces the coupling of the control process, guarantees the stability of the control system, reduces the tracking error of the depth and the attitude angle of the ROV, and greatly improves the control performance of the depth and the attitude angle of the ROV. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 is a comparison schematic diagram of the ROV carrier coordinate system and the world coordinate system;

[0039] Figure 2 is a schematic diagram of target depth and attitude solving principle;

[0040] Figure 3 is a general structure diagram of the ROV depth and attitude decoupling control method based on spatial surface depth proposed by the present application. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail in combination with the drawings. The description introduces the specific embodiments consistent with the principles of the present application by way of examples but not by limitation, and the description of the embodiments is sufficiently detailed to enable those skilled in the art to practice the present application, other embodiments can be used and the structure of each element can be changed and / or replaced without departing from the scope and spirit of the present application. Therefore, the following detailed description should not be understood in a limiting sense.

[0042] As shown in Figure 3 the ROV depth and attitude decoupling control method based on spatial surface depth of the present application comprises:

[0043] Step 100: establishing a depth model of a four-axis vertical propeller unmanned remote control submersible ROV; obtaining the actual centroid depth and the actual attitude angle of the unmanned remote control submersible ROV, inputting the actual centroid depth and the actual attitude angle of the unmanned remote control submersible ROV into the depth model, and the depth model outputting the actual depth of each vertical propeller of the unmanned remote control submersible ROV; inputting the target centroid depth and the target attitude angle of the unmanned remote control submersible ROV into the depth model, and the depth model outputting the target depth of each vertical propeller of the unmanned remote control submersible ROV.

[0044] In Step 1, the depth model of the four vertical propellers of the unmanned remotely operated vehicle ROV is as follows:

[0045] Depth1 = z1 + Depth

[0046] Depth2 = z2 + Depth

[0047] Depth3 = z3 + Depth

[0048] Depth4 = z4 + Depth

[0049] wherein Depth1, Depth2, Depth3 and Depth4 represent the depths of the first, second, third and fourth vertical propellers of the unmanned remotely operated vehicle ROV respectively; z1, z2, z3 and z4 represent the Z-axis coordinates of the first, second, third and fourth vertical propellers of the unmanned remotely operated vehicle ROV in the world coordinate system respectively; and Depth represents the centroid depth of the unmanned remotely operated vehicle ROV.

[0050] As shown in Figure 1 , the world coordinate system is established with the centroid of the unmanned remotely operated vehicle ROV as the coordinate origin, with the projection of the longitudinal axis of the unmanned remotely operated vehicle ROV carrier pointing to the head direction in the horizontal plane where the origin is located as the X-axis, with the vertically downward direction as the Z-axis, and with the Y-axis being perpendicular to the XOZ plane and satisfying the right-hand rule.

[0051] The Z-axis coordinates of the first, second, third and fourth vertical propellers of the unmanned remotely operated vehicle ROV in the world coordinate system are as follows:

[0052]

[0053]

[0054]

[0055]

[0056] wherein L x , L y and L z represent the X0-axis, Y0-axis and Z0-axis coordinates of the first vertical propeller of the unmanned remotely operated vehicle ROV in the carrier coordinate system respectively; and ψ and represent the pitch angle and roll angle of the unmanned remotely operated vehicle ROV respectively, i.e., the attitude angle of the unmanned remotely operated vehicle ROV.

[0057] The attitude angle and the centroid depth Depth of the ROV are obtained, wherein θ is the heading angle, ψ is the pitch angle, The roll angle is given; the carrier coordinates of the first vertical propeller in the first quadrant of the carrier coordinate system are [L]. x L y L z ] T The world coordinates [x1, y1, z1] of vertical propeller 1 are obtained by analyzing the attitude angle. T The details are as follows:

[0058]

[0059] The ROV's vertical propellers are symmetrically distributed. The world coordinates of the second vertical propeller, which is symmetrical to the first vertical propeller about the X-axis, are [x2, y2, z2]. T The world coordinates of the third vertical propeller, which is symmetrical to the first vertical propeller about the Y-axis, are [x3, y3, z3]. T The world coordinates of the fourth vertical propeller, which is symmetrical to the first vertical propeller about the origin, are [x4, y4, z4]. T It satisfies the following relationship:

[0060]

[0061] z3=z1+2L x sin(ψ)

[0062]

[0063] like Figure 1 As shown, the carrier coordinate system is specifically established with the centroid of the ROV as the origin, the longitudinal axis pointing towards the head as the X0 axis, the transverse axis pointing to the right of the head's forward direction as the Y0 axis, and the direction pointing towards the bottom of the carrier as the Z0 axis. The first vertical propeller of the ROV is located in the first quadrant of the carrier coordinate system. The second vertical propeller is symmetrical about the X0 axis, the third vertical propeller is symmetrical about the Y0 axis, and the fourth vertical propeller is symmetrical about the center of the origin of the carrier coordinate system.

[0064] In step 100, a depth sensor and an electronic compass are installed at the center of the hull of the unmanned remotely operated vehicle (ROV). The actual centroid depth of the ROV is obtained based on the depth sensor, and the actual attitude angle of the ROV is obtained based on the electronic compass.

[0065] Step 200: a decoupling control model of the quad-rotor vertical propeller unmanned remotely operated vehicle (ROV) is established; actual depths and target depths of each vertical propeller of the unmanned remotely operated vehicle (ROV) are input into the decoupling control model, and the decoupling control model outputs input control quantities of each vertical propeller of the unmanned remotely operated vehicle (ROV), so as to realize independent closed-loop control of each vertical propeller of the unmanned remotely operated vehicle (ROV) respectively.

[0066] In step 200, the decoupling control model of the quad-rotor vertical propeller unmanned remotely operated vehicle (ROV) is as follows:

[0067] U1(s) = [DEPTH t1 (s) - DEPTH r1 (s)] G1(s)

[0068] U2(s) = [DEPTH t2 (s) - DEPTH r2 (s)] G2(s)

[0069] U3(s) = [DEPTH t3 (s) - DEPTH r3 (s)] G3(s)

[0070] U4(s) = [DEPTH t4 (s) - DEPTH r4 (s)] G4(s)

[0071] Wherein, U1(s), U2(s), U3(s) and U4(s) represent input control quantities of the first, second, third and fourth vertical propellers of the unmanned remotely operated vehicle (ROV) in the form of Laplace transformation, and s represents complex frequency; DEPTH t1 (s), DEPTH t2 (s), DEPTH t3 (s) and DEPTH t4 (s) represent target depths of the first, second, third and fourth vertical propellers of the unmanned remotely operated vehicle (ROV) in the form of Laplace transformation; DEPTH r1 (s), DEPTH r2 (s), DEPTH r3 (s) and DEPTH r4 (s) represent actual depths of the first, second, third and fourth vertical propellers of the unmanned remotely operated vehicle (ROV) in the form of Laplace transformation; and G1(s), G2(s), G3(s) and G4(s) represent transfer functions of closed-loop controllers of the first, second, third and fourth vertical propellers of the unmanned remotely operated vehicle (ROV) respectively. The closed-loop controller can be a PID controller.

[0072] All vertical propellers of the ROV are closed-loop controlled respectively with the target value of the target depth of the vertical propeller and the actual value of the actual depth of the vertical propeller, so as to obtain the input control amount of each vertical propeller, and finally make the attitude angle and the centroid depth of the ROV close to and reach the target value.

[0073] As shown in Figure 1 , the carrier coordinate system changes with the carrier attitude and heading, the centroid of the ROV is taken as the coordinate origin, the longitudinal axis of the carrier points to the head direction as the X0 axis, the transverse axis of the carrier points to the right side direction of the carrier as the Y0 axis, and the direction pointing to the bottom of the carrier as the Z0 axis, the angle of rotation along the X0 axis is the roll angle, the angle of rotation along the Y0 axis is the pitch angle, and the angle of rotation along the Z0 axis is the heading angle. The X axis in the world coordinate system is always in the horizontal plane, the direction is consistent with the projection of the head direction of the ROV in the horizontal plane, the Z axis is perpendicular to the horizontal plane downward, and the Y axis direction is 90° clockwise rotation of the X axis direction.

[0074] As shown in Figure 2 , when the target depth and attitude solving step is executed, the z t1 , z t2 , z t3 , z t4 of the target world coordinate of each vertical propeller is the target depth of the vertical propeller relative to the centroid of the ROV, and the target centroid depth Depth t of the ROV is the target depth of the centroid of the ROV relative to the sea level. The target world coordinate of the vertical propeller can be obtained through the target attitude angle solving of the ROV, and then the target depth z t1、 z t2 , z t3 , z t4 of each vertical propeller relative to the centroid of the ROV is added to the target depth Depth t of the centroid of the ROV relative to the sea level, so as to obtain the target depth Depth t1 , Depth t2 , Depth t3 , Depth t4 of each vertical propeller relative to the sea level.

[0075] As shown in Figure 3As shown, in the execution of the ROV depth and attitude decoupling control method based on spatial surface depth proposed by the application, first, the target depth and attitude calculation step is performed, and the target depth of the four vertical propellers is calculated according to the target centroid depth and target attitude angle of the ROV obtained; then, the vertical propeller positioning is performed, the actual attitude angle measured by the electronic compass and the actual centroid depth measured by the depth gauge installed near the centroid of the ROV are obtained, and then the actual depth of the four vertical propellers is calculated; finally, the vertical propeller depth independent closed loop control is performed, an independent closed loop controller is constructed for the four vertical propellers, the calculated target depth of the vertical propeller is taken as the target value, the calculated actual depth of the vertical propeller is taken as the actual value input into the closed loop controller, the input control amount of the four vertical propellers is obtained respectively, and the rotation speed of the four vertical propellers is controlled to adjust the four vertical propellers to the target depth, so as to finally act on the depth and attitude change of the ROV.

Claims

1. A method for decoupling control of ROV at fixed depth and attitude based on spatial plane depth, characterized in that, include: Step 100: Establish a depth model of the quadcopter vertical propeller-driven remotely operated vehicle (ROV); Obtain the actual centroid depth and actual attitude angle of the ROV. Input the actual centroid depth and actual attitude angle of the ROV into the depth model. The depth model outputs the actual depth of each vertical propeller of the ROV. Input the target centroid depth and target attitude angle of the ROV into the depth model. The depth model outputs the target depth of each vertical propeller of the ROV. Step 200: Establish a decoupled control model for a quadcopter vertical propeller ROV; input the actual depth and target depth of each vertical propeller of the ROV into the decoupled control model, and output the input control quantities of each vertical propeller of the ROV, thereby realizing independent closed-loop control of each vertical propeller of the ROV.

2. The ROV fixed-depth and fixed-attitude decoupling control method based on spatial plane depth according to claim 1, characterized in that: In step 1, the depth model of the quadcopter vertical propeller-driven remotely operated vehicle (ROV) is as follows: Depth1=z1+Depth Depth2=z2+Depth Depth3=z3+Depth Depth4=z4+Depth Where Depth1, Depth2, Depth3, and Depth4 represent the depths of the first, second, third, and fourth vertical propellers of the ROV, respectively; z1, z2, z3, and z4 represent the Z-axis coordinates of the first, second, third, and fourth vertical propellers of the ROV in the world coordinate system, respectively; and Depth represents the centroid depth of the ROV.

3. The ROV fixed-depth and fixed-attitude decoupling control method based on spatial surface depth according to claim 2, characterized in that: The world coordinate system is specifically established with the centroid of the ROV as the origin, the projection of the ROV's longitudinal axis pointing towards its head onto the horizontal plane at the origin as the X-axis, the vertically downward direction as the Z-axis, and the Y-axis perpendicular to the XOZ plane and satisfying the right-hand rule.

4. The ROV fixed-depth and fixed-attitude decoupling control method based on spatial plane depth according to claim 2, characterized in that: The Z-axis coordinates of the first, second, third, and fourth vertical propellers of the aforementioned remotely operated vehicle (ROV) in the world coordinate system are as follows: Among them, L x L y and L z Represent the X0, Y0, and Z0 coordinates of the first vertical propeller of the remotely operated vehicle (ROV) in the carrier coordinate system; ψ and These represent the pitch and roll angles of an unmanned remotely operated vehicle (ROV), which are the attitude angles of the ROV.

5. The ROV fixed-depth and fixed-attitude decoupling control method based on spatial surface depth according to claim 4, characterized in that: The aforementioned carrier coordinate system is specifically established with the centroid of the ROV as the origin, the longitudinal axis pointing towards the head as the X0 axis, the transverse axis pointing to the right of the head's forward direction as the Y0 axis, and the direction pointing towards the bottom of the carrier as the Z0 axis. The first vertical propeller of the ROV is located in the first quadrant of the carrier coordinate system. The second vertical propeller is symmetrical about the X0 axis, the third vertical propeller is symmetrical about the Y0 axis, and the fourth vertical propeller is symmetrical about the center of the origin of the carrier coordinate system.

6. The ROV fixed-depth and fixed-attitude decoupling control method based on spatial plane depth according to claim 1, characterized in that: In step 100, a depth sensor and an electronic compass are installed at the center of the hull of the unmanned remotely operated vehicle (ROV). The actual centroid depth of the ROV is obtained based on the depth sensor, and the actual attitude angle of the ROV is obtained based on the electronic compass.

7. The ROV fixed-depth and fixed-attitude decoupling control method based on spatial plane depth according to claim 1, characterized in that: In step 200, the decoupled control model of the quadcopter vertical propeller-driven remotely operated vehicle (ROV) is as follows: U1(s)=[DEPTH t1 (s)-DEPTH r1 (s)]G1(s) U2(s)=[DEPTH t2 (s)-DEPTH r2 (s)]G2(s) U3(s)=[DEPTH t3 (s)-DEPTH r3 (s)]G3(s) U4(s)=[DEPTH t4 (s)-DEPTH r4 (s)]G4(s) Where U1(s), U2(s), U3(s), and U4(s) represent the Laplace transform input control quantities of the first, second, third, and fourth vertical propellers of the remotely operated vehicle (ROV), respectively, and s represents the complex frequency; DEPTH t1 (s), DEPTH t2 (s), DEPTH t3 (s) and DEPTH t4 (s) represent the target depth in the Laplace transform form of the first, second, third, and fourth vertical propellers of the remotely operated vehicle (ROV), respectively. r1 (s), DEPTH r2 (s), DEPTH r3 (s) and DEPTH r4 G(s) represents the actual depth in the Laplace transform form of the first, second, third, and fourth vertical propellers of the ROV, and G1(s), G2(s), G3(s), and G4(s) represent the transfer functions of the closed-loop controllers of the first, second, third, and fourth vertical propellers of the ROV, respectively.

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