An underwater dual-rotor multi-input multi-output control experimental platform

Abstract

The present invention discloses an underwater dual-rotor multi-input and multi-output control experimental platform, which belongs to the field of underwater unmanned helicopter control technology. The experimental platform includes: a transparent water tank, and two underwater thrusters (main rotor and tail rotor) arranged in the transparent water tank, a crossbeam, a connecting rod, a swinging head, an electrical control box, a vertical bearing seat, a rotating base, a support rod and a horizontal bearing seat. The experimental platform of the present invention is a high-order nonlinear complex underwater control system with strong cross-coupling, which is similar to an underwater helicopter in terms of motion control. In-depth research and practice can be carried out on this system for problems such as feedback linearization, decoupling control, real-time digital control, stability control, tracking control, and fuzzy logic control.

Description

Technical Field

[0001] The present invention relates to the technical field of underwater UAV control, and in particular to an underwater dual-rotor multi-input multi-output control experimental platform. Background Art

[0002] The Underwater Unmanned Helicopter (AUH), developed based on new principles and technologies, addresses key marine science and technology challenges, such as developing autonomous submersibles to enhance their maneuverability and diversify their operating modes. The AUH is a new type of unmanned underwater vehicle with strong stability and reliability, capable of operating from deep sea to offshore locations. It can hover at a fixed point, perform full-circle maneuvers, and perform free takeoff and landing in the ocean, as well as conduct round-trip operations between subsea workstations.

[0003] To save costs, laboratory rotor platforms are often used to simulate complex drone operations and test new control strategies. However, since there are currently few manufacturers developing such rotor control platform experimental devices and traditional dual-rotor multi-input multi-output systems basically do not involve control research on underwater unmanned helicopters, they cannot meet the requirements of underwater environmental control experiments and have their own limitations in analyzing the performance of underwater propellers and their rotors. Therefore, based on the traditional dual-rotor multi-input multi-output system experimental device, in order to simulate complex operations and test control strategies for underwater unmanned helicopters and reduce the cost of TRMS experiments and teaching in domestic universities, the inventors designed an underwater dual-rotor multi-input multi-output control experimental platform by studying the models and simulation cases of traditional dual-rotor multi-input multi-output systems and combining them with the requirements of current underwater environmental control experiments. Summary of the Invention

[0004] The purpose of the present invention is to provide an underwater dual-rotor multi-input multi-output control experimental platform to address the deficiencies of the above-mentioned prior art.

[0005] The technical solution adopted in the present invention is:

[0006] An underwater dual-rotor multi-input multi-output control experimental platform includes a transparent water tank, two underwater thrusters (main rotor and tail rotor), a crossbeam, a connecting rod, a swinging head, an electrical control box, a vertical bearing seat, a rotating base, a support rod and a horizontal bearing seat;

[0007] In the above technical solution, further, the two underwater thrusters are arranged at both ends of the crossbeam, wherein the main rotor is placed perpendicular to the horizontal axis of the crossbeam, and the tail rotor is placed parallel to the horizontal axis of the crossbeam;

[0008] Furthermore, the crossbeam is provided with a plurality of through holes (such as a design of two rows of symmetrical triangular holes) to reduce the fluid resistance encountered by the crossbeam when performing pitching motion underwater.

[0009] Furthermore, the swinging head and the crossbeam are connected and fixed into a whole through a connecting rod and vertical bearing seats arranged on both sides of the swinging head. The main rotor generates a vertical (along the Y axis) propulsion force so that the crossbeam can produce pitch motion in the vertical (XY) plane.

[0010] Furthermore, the vertical bearing seats on both sides are fixed to the rotating base by connecting bolts, and the rotating base is tightly fixed to the sleeve in the horizontal bearing seat through the support rod at the bottom thereof, and the tail rotor generates a lateral (along the Z axis) propulsion force so that the crossbeam can swing in the horizontal (XZ) plane;

[0011] Furthermore, the horizontal bearing seat is fixed by through holes around it and threaded holes on the boss on the inner bottom surface of the transparent water tank, so that the crossbeam of the underwater dual-rotor multi-input multi-output control experimental platform will not have any other form of movement posture except the pitch posture in the XY plane and the swing posture in the XZ plane during movement.

[0012] Furthermore, a groove is provided on the top of the swinging head for embedding an electrical control box, wherein the electrical control box mainly integrates a position sensor, a motor speed regulating device, a data acquisition card, a wireless transmission chip and a power supply.

[0013] In addition, the blades of the two underwater propellers described in the present invention can adopt any hydrodynamic shape that generates vertical / lateral thrust.

[0014] The beneficial effects of the present invention are:

[0015] The underwater dual-rotor multi-input multi-output control experimental platform provided by the present invention can perform verification experiments on the control method of the underwater propeller and the algorithm for adjusting parameters, as well as comparative analysis of actual control effects while meeting the requirements of underwater environment control experiments.

[0016] The experimental platform of this invention is a complex, high-order nonlinear underwater control system with strong cross-coupling, similar to an underwater helicopter in terms of motion control. This system allows for in-depth research and practical application on issues such as feedback linearization, decoupling control, real-time digital control, stability control, tracking control, and fuzzy logic control.

[0017] The experimental platform of the present invention can compare the propulsion efficiency and speed regulation performance of the underwater thruster and its propeller by obtaining and analyzing the waveform of the beam position in real time under the conditions of consistent experimental environment, control method and parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the overall structure diagram of the underwater dual-rotor multi-input multi-output control experimental platform provided by the present invention;

[0019] Figure 2 A top view (a) and a longitudinal cross-sectional view (b) of the crossbeam of the underwater dual-rotor multi-input multi-output control experimental platform provided by the present invention;

[0020] Figure 3 Three views of the swinging head of the underwater dual-rotor multi-input multi-output control experimental platform provided by the present invention, (a), (b) and (c) are the front view, left view and top view respectively;

[0021] Figure 4 These are the simulation results of the 2-DOF PID control system of the underwater dual-rotor multi-input multi-output control experimental platform, where (a) is the pitch channel and (b) is the yaw channel. DETAILED DESCRIPTION

[0022] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0023] like Figure 1 The figure shows an underwater dual-rotor multi-input and multi-output control experimental platform of the present invention, which includes a transparent water tank 1, two underwater thrusters (main rotor 9 and tail rotor 2), a beam 8, a connecting rod 7, a swinging head 5, an electrical control box 6, a vertical bearing seat 10, a rotating base 3, a support rod 4 and a horizontal bearing seat 11; the beam is designed with two symmetrical rows of symmetrical triangular holes, and the longitudinal section through the center of the beam 8 has a horizontal circular hole that completely passes through on both sides; the two underwater thrusters main rotor 9 and tail rotor 2 are symmetrically fixed at both ends of the beam 8 by connecting bolts, the main rotor 9 is placed perpendicular to the horizontal axis of the beam 8, and the tail rotor 2 is placed parallel to the horizontal axis of the beam 8.

[0024] like Figure 2 As shown, the longitudinal section of the center of the swinging head 5 also has a horizontal circular hole completely passing through on both sides. The swinging head 5 and the crossbeam 8 are connected and fixed into a whole through a connecting rod and the vertical bearing seats 10 on both sides.

[0025] like Figure 3 As shown, an electrical control box 6 is embedded in the top of the swinging ram, and the through holes at the upper left and lower right corners of the electrical control box 6 are respectively assembled and fixed with the threaded holes at the upper left and lower right corners in the groove at the top of the swinging ram 5 by connecting bolts.

[0026] The vertical bearing seats 10 on both sides are fixed to the rotating base 3 by connecting bolts. The rotating base 3 is tightly fixed to the sleeve in the horizontal bearing seat 11 through the support rod 4 at its bottom. The horizontal bearing seat 11 is positioned by connecting bolts through the through holes around it and the threaded holes on the boss on the inner bottom surface of the transparent water tank 1.

[0027] The blades of the two underwater propellers can adopt any hydrodynamic shape that generates vertical / lateral thrust.

[0028] The working process of the experimental platform of the present invention is as follows:

[0029] The angles between the beam 8 and the horizontal and vertical axes of the transparent water tank's spatial coordinate system are called the pitch and yaw angles, respectively. By controlling the rotation rates of the main rotor 9 and tail rotor 2, the hydrodynamic forces generated around the two rotors are altered. These forces work together to achieve real-time control of the beam 8's pitch and yaw angles. The position of the beam 8 is measured by the pitch and yaw angles. When their expected values ​​are discontinuous signals and serve as input commands to the control platform, the beam 8 can be stabilized at any desired position within the angular range (in which case the drone can remain in a hovering state). When their expected values ​​are continuous signals, the beam 8 can be controlled to track any desired trajectory that conforms to the rules (in which case the drone can move along the predetermined trajectory). The real-time pitch and yaw angles of the beam 8 (actual position), as well as their angular variations, are measured by the electrical control box 8 and fed back to the controller as outputs of the underwater dual-rotor multi-input multi-output control experimental platform, forming a complete closed-loop control system.

[0030] Under the conditions of consistent experimental environment, control methods and parameters, the waveform of the beam position can be obtained in real time and analyzed to compare the propulsion efficiency and speed regulation performance of the underwater thruster and its rotor.

[0031] like Figure 4 The simulation results for the 2-DOF PID control system of the control experimental platform of the present invention are shown. As can be seen from the figure, when the signals for setting the desired pitch and yaw angles of the underwater dual-rotor multi-input multi-output control experimental platform are continuous values ​​that change over time, the control experimental platform PID control system of the present invention can enable the underwater dual-rotor system to achieve trajectory tracking and complete tracking control functions.

Claims

1. An underwater dual-rotor multi-input multi-output control experimental platform, characterized in that: The invention comprises a transparent water tank (1), two underwater propellers, a crossbeam (8), a connecting rod (7), a swinging head (5), a vertical bearing seat (10), a rotating base (3), a supporting rod (4) and a horizontal bearing seat (11); the two underwater propellers are a main rotor (9) and a tail rotor (2); the main rotor (9) is placed perpendicular to the horizontal axis of the crossbeam (8), and the tail rotor (2) is placed parallel to the horizontal axis of the crossbeam (8); the horizontal bearing seat (11) is arranged at the bottom of the transparent water tank (1); The longitudinal section of the center of the swinging head (5) is provided with a horizontal circular hole completely passing through on both sides; The longitudinal section of the center of the crossbeam (8) has a horizontal circular hole completely passing through on both sides; the connecting rod (7) is used to connect the crossbeam (8), the swinging head (5) and the vertical bearing seats (10) provided on both sides of the swinging head (5) into a whole, and the whole is fixed on the rotating base (3) so that the crossbeam can generate pitching motion in the vertical plane; The rotating base (3) is tightly fitted and fixed to the sleeve in the horizontal bearing seat (11) via the support rod (4) at the bottom thereof, so that the crossbeam (8) can swing in the horizontal plane; When the main rotor (9) and the tail rotor (2) are in motion, the center of the crossbeam (8) is used as the coordinate origin, so that the crossbeam (8) can produce a pitching attitude in the vertical plane and a swinging attitude in the horizontal plane; The crossbeam (8) is provided with a plurality of through holes for reducing the fluid resistance encountered by the crossbeam when performing pitching motion underwater.

2. The underwater dual-rotor multi-input multi-output control experimental platform according to claim 1 is characterized in that: The vertical bearing seat (10) is fixed on the rotating base (3) by connecting bolts.

3. The underwater dual-rotor multi-input multi-output control experimental platform according to claim 1 is characterized in that: The top of the swinging head (5) is provided with a groove for embedding an electrical control box (6); the electrical control box (6) is used to realize the following functions: real-time position detection, data acquisition, motor speed regulation, wireless data transmission and power supply.

4. The underwater dual-rotor multi-input multi-output control experimental platform according to claim 1, characterized in that: The horizontal bearing seat (11) is fixed to the bottom of the transparent water tank (1) by connecting bolts, so that the crossbeam (8) of the underwater dual-rotor multi-input multi-output control experimental platform can only move in the vertical plane and the horizontal plane during the movement process.

5. The underwater dual-rotor multi-input multi-output control experimental platform according to claim 1, characterized in that: The blades of the two underwater propellers can adopt any hydrodynamic shape that generates vertical / lateral thrust.

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