RU2269451C1 - Auto-pilot at estimation of angular velocity - Google Patents

Abstract

FIELD: shipbuilding; ship motion automatic control equipment.

SUBSTANCE: proposed auto-pilot includes course angle setter, rudder angle sensor, two antennae, satellite navigational system receiver, steering gear, integrator, differentiator and adder. It is additionally provided with angular velocity sensor, re-tuning unit, multiplier and running speed square sensor.

EFFECT: enhanced stability of ship in course; increased reserve of stability of closed control system.

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Description

The invention relates to shipbuilding, in particular to the field of automatic control of the movement of a sea vessel,

A device is known (AS USSR No. 460535), providing automatic deduction of the vessel at a given course. The stabilization of the course is carried out according to the gyrocompass, which is the main source of information about the direction of movement of the vessel. The signal of the current course and its derivative enter the input of the calculator (summing device), the input of which also receives the signal from the rudder angle sensor.

Considered autopilot has the following disadvantages:

- overloads the steering gear with developed sea waves;

- the heading angle signal generated by the gyrocompass is noisy, and during differentiation it is not possible to obtain the heading derivative signal with the required dynamic qualities, which excludes its use on ships that are unstable on course.

Also known is the “Automatic Vessel Traffic Control Equipment” (Russian patent No. 2221728, class B 63 H 25/04), which we adopted as a prototype, containing a directional adjuster, rudder angle sensor, the outputs of which are connected to a computer (summing amplifier) . To the calculator are also connected:

- signal from the output of the receiver of the satellite navigation system (SNA) track angle (PU));

- evaluation of the angular velocity signal, which is generated by the differentiator and the summing unit with an integrator, the output of which is connected through the summing unit to the input of the steering gear, the latter, deflecting the steering wheel, holds the vessel in a given direction of movement.

This equipment provides automatic control of the movement of a small vessel. Installation of equipment on large vessels does not provide the required accuracy of holding a large vessel in a given direction of movement, because reconstructing the signal derivative of the course angle to correct the signal estimate is not effective enough. Therefore, the developed estimate of the angular velocity of the vessel at the output of the integrator is far from real, and the use of the derivative of the heading signal for correction of the estimate, as shown by operating experience, is ineffective. (High dynamic qualities of the angular velocity signal of the vessel “ω” are especially important to ensure the necessary margin of stability of the closed system: “Auto steering - steering drive - ship”).

Thus, the considered equipment has the following disadvantages:

- the derivative of the course angle (ω = d / dt φ) is generated very noisy, which does not allow the use of this equipment on large sea vessels, and on river vessels that are unstable on course;

- restoration of the estimate of the angular velocity of the vessel (using a stationary non-tunable mathematical model of the vessel) is not effective, since the estimate obtained is far from real;

- due to interference with developed sea waves, even on steadily navigating marine vessels, overload of the steering drive is observed.

In the auto steering proposed by us, the above-mentioned disadvantages are eliminated.

The problem solved by the present invention is the creation of equipment for automatic control of the movement of the vessel, providing increased accuracy of stabilization of the vessel with the required safety margin of a closed control system. (An autopilot must work efficiently both on course-stable vessels, and on unstable on-course sea and river vessels). The problem is solved by developing a high-quality signal for estimating the angular velocity of the vessel (in dynamics).

An autopilot with an estimate of the angular velocity is proposed, comprising a directional angle adjuster, a rudder angle sensor, two antennas, a satellite navigation receiver, a steering gear, an integrator, a differentiator and an adder, the first input of which is connected to the output of the angle adjuster, to the first and second inputs of the receiver SNA is connected to the first and second antennas, the first output of the SNA receiver is connected to the second input of the adder, to the third input of which the output of the rudder angle sensor is connected, the output of the adder is connected to the input of the steering wheel th actuator, a fourth adder input connected to the output of the integrator, a first input of which is connected via a differentiator to the second output SNS receiver. Compared with the known autopilot, it additionally contains an angular velocity sensor, a tuning block, a multiplier and a square-speed sensor, the output of which is connected to the first input of the multiplier, to the second input of which the output of the rudder angle sensor is connected, the output of the multiplier is connected to the second input of the integrator, to the third the input of which the output of the angular velocity sensor is connected, the output of the integrator is connected to the fourth input of the integrator through the tuning block.

A significant novelty of the invention is:

- development of an estimate of the angular velocity of the vessel (Ω) using the model of angular motion of the vessel that is tunable during the voyage,

- the generation of the current angular velocity (to adjust the estimate) is carried out not only by differentiating the course angle signal, but also by using the angular velocity signal from the angular velocity sensor,

- the development of close to real estimates of the angular velocity of the vessel became possible due to the introduction of measurements of the angular motion of the vessel at the input: the angular velocity of the vessel from the angular velocity sensor and the derivative of the heading angle from the SNA receiver.

Functional diagram of the invention is shown in the drawing.

An autopilot with an estimate of the angular velocity contains a directional angle adjuster 1, a rudder shift sensor 2, two antennas 3, 4, a satellite navigation system (SNA) receiver 5, an adder 6, a steering gear 7, an integrator 8, a differentiator 9, a vessel angular velocity sensor ( ДУС) 10, factor 11, sensor of the square of the speed of the vessel 12, adjustment block 13. The control object of the vessel 14.

As an adjuster 1 and a rudder angle sensor 2, any analog (digital) commercially available converter of the angle of rotation into a signal with an accuracy of at least 0.5% can be used. Antennas 3, 4 are equipped with the SNS 5 receiver - of the “Volunteer” type (in our equipment, the receiver is supplemented with a second input for connecting the second antenna. Receiver 5 manufactured by the Japanese company Furuno Elektric Co.LTD. “Model SC-120” can also be used). Squared speed sensor An 8-state ship device with a quad connected to its output (you can use information about the speed of the vessel from the output of the SNA 5 receiver). The angular velocity sensor 10 of the DUS-6 type with a sensitivity of no worse than 0.005 g / s. The integrator 8, the differentiator 9, the multiplier 11 in the analog implementation are integrated circuits of type 140 - UD - 6. and 140 - UD - 8. (Differentiator 9 is an integrated circuit of type 140 - UD - 6 with a small leakage capacitor connected to the input Integrator 8 is an integrated microcircuit of type 140 - UD - 8. Squared speed sensor 12 is a ship's log with a squaring block at the output. Tuning block 13 is a set of manually switched resistors. The second antenna 4 can be used from an MRK type goniometer - 11 for satellite on igatsionnyh systems GLONASS and GPS, the development of the Research Institute of Radio Engineering of the Krasnoyarsk State Technical University. It is also possible the implementation of a digital autopilot on the serial microcontroller.

The equipment operates as follows.

The direction of movement of the vessel is set by the master of the direction angle 1. If this direction of movement of the vessel does not coincide with the current direction, then the signal “d / dt δ _rear ” will appear at the output of the adder 6 (depending on the type of steering machine instead of the signal “d / dt δ _rear ” a signal “δ _ed ” can be generated), which leads to a deviation of the rudder of the vessel by the steering gear 7, after which the vessel begins to turn to a given direction of movement. When the vessel reaches the specified direction of movement, the rudder feather will return to the balancing position.

Consider how the steering law of control is formed 7. A signal proportional to the current direction of the vessel — PU, is generated at the output of the SNA 5 receiver and fed to the second input of adder 6, the first input of which receives a signal from master 1 — the given direction of the vessel — PU _health At the output of the adder 6, a signal will be formed of the deviation of the vessel from a given direction of movement: Δ PU = PU-PU _building . The remaining two signals “δ, Ω”, fed to the input of the adder 6, are necessary to ensure a given accuracy of stabilization of the vessel, as well as to provide the required margin of stability of the closed-loop control system: “autopilot - steering gear - ship”. The signal "δ" comes from the rudder angle sensor 2, the signal for estimating the angular velocity of the vessel "Ω" comes from the output of the integrator 8. Thus, the following steering control law is formed:

d / dt δ _zd = K ₁ ΔPU + K ₂ Ω-K ₃ δ,

where d / dt δ _rear - the specified speed of the rudder,

Δ PU = PU-PU _rear - the error signal along the track angle,

 Ω is the estimate of the angular velocity signal of the vessel,

δ is the rudder angle,

K ₁ , K ₂ , K ₃ - regulation coefficients.

Let us consider how the estimation of the angular velocity of the vessel “Ω” is formed. For a sufficiently wide class of vessels, the mathematical model of angular motion can be represented as

where Ω ₁ , d / dt Ω ₁ is the angular velocity of the vessel and its derivative,

δ is the rudder angle,

K ₁₁ = const, K ₁₃ = f (v) = KV ² ,

V is the speed of the ship.

The solution of equation (1) is implemented at the output of the integrator 8, because the fourth input of the integrator receives the signal of the angular velocity of the vessel, which comes in the form of negative feedback from the output of the integrator through the adjustment unit 13, and the second input receives the signal of the angle of the rudder, multiplied by the square of the speed. At the output of the integrator 8, a signal for estimating the angular velocity of the vessel “Ω” is generated, which may differ significantly from the current value of the angular velocity of the vessel. To maximize the approximation of the estimate to the actual smoothed value of the signal of the angular velocity of the vessel, the correction signal derivative of the course angle “ω ₁ ” is introduced to the first input of the integrator, and the signal of the angular velocity of the vessel generated by the TLS ohm - 10 is introduced to the third input:

where Ω, d / dt Ω is the estimate of the angular velocity of the vessel and its derivative,

δ is the rudder angle,

K ₁₁ = f (vessel load, trim angle), K ₁₂ = const., K ₁₃ = f (v) = KV ² , K ₁₄ = const.

V is the speed of the ship.

Features of the development of the signal of the course angle (φ).

High accuracy of measuring the angle of rotation of the vessel can be achieved by adding a second antenna - an auxiliary antenna, also located on the vessel with a rigidly fixed distance between the two antennas. This will allow us to determine the heading angle φ using the interferometric principle (see Cohen. C. E. Attitude determination. Global Positioning System. Theory and - Applications, American Institute of Aeronautics and Astronautics, Washington., C. - 1996, Vol.II. Chapter 19. - P.519-538.). Its essence is to measure the phase difference of the carrier frequency for signals received from satellites on diversity antennas. These differences, due to the unequal distance to the satellites of the two antennas, contain information about the angle between the direction to the satellites and the vector formed between the two antennas. Using data on the angles between the directions to several satellites and two antennas, with their known location on the ship, the problem of determining the angle of course is solved. Similar systems are currently developed and used in aviation (Graas FV ... Interferometric GPS flight reference autoland system: Flight test results. Navigation, USA-1994, Vol.41, X2 1. - P.57-82.) heading angle measurement is mainly determined by the ratio of the total error of the measurement of the phase shift, expressed in units of length, to the distance between the antennas - the length of the base. According to the IEEE Aerospace and Electronic Systems Society Las Vegas, Nevada. April 11-15, PLANS 94. - 1994. - P.806-812 accuracy ranges from 0.02-0.3 gr. with the base between the antennas L = 40-1 m.

The given accuracy of measuring the course angle significantly exceeds the accuracy of generating the course angle by commercially available gyrocompasses. (The track angle when using positional-speed information used in the receiver of the Volunteer Navigation System and other similar systems is also measured much more roughly). Using an auxiliary (second) antenna in our equipment, it is possible to develop a high-quality current course angle φ.

The simulation of the above laws (1, 3) confirmed the possibility of obtaining highly efficient equipment for the automatic control of the vessel’s movement both in terms of the accuracy of stabilization of the vessel at a given ground angle and in terms of the stability margin of a closed system.

Claims (1)

An autopilot with an estimate of the angular velocity, comprising a directional angle adjuster, a rudder angle sensor, two antennas, a satellite navigation system receiver, a steering gear, an integrator, a differentiator and an adder, the first input of which is connected to the output of the angle adjuster to the first and second inputs of the satellite receiver of the navigation system, the first and second antennas are connected, the first output of the satellite navigation system receiver is connected to the second input of the adder, to the third input of which the output of the angle sensor the steering tabs, the adder output is connected to the input of the steering gear, the fourth adder input is connected to the integrator output, the first input of which is connected via a differentiator to the second output of the satellite navigation system receiver, characterized in that it further comprises an angular velocity sensor, a tuning unit, a multiplier and a square sensor speed, the output of which is connected to the first input of the multiplier, to the second input of which the output of the rudder angle sensor is connected, the output of the multiplier is connected to the second input of the integ torus, to the third input of which the output of the angular velocity sensor is connected, the output of the integrator is connected to the fourth input of the integrator through the tuning block.