CN106557088A - A ship heading controller based on event trigger mechanism and its control method - Google Patents

Abstract

The invention discloses a ship course controller based on an event trigger mechanism and a control method thereof, wherein the controller comprises a reference module, a trigger module and a controlled module, the trigger module comprises a calculation unit, a comparison unit and an instruction unit, and the controlled module comprises a control unit, a digital-to-analog conversion unit, a PWM signal output unit, an execution mechanism, a controlled unit, an analog-to-digital conversion unit and a data processing unit; the trigger module is respectively connected with the output end of the reference module, the output end of the controlled unit in the controlled module and the input end of the control unit in the controlled module. The invention not only reduces the calculation and update burden of the ship course control system on the control signal, avoids the high-frequency state switching of the ship steering device and the high-frequency friction of control parts, but also reduces the energy consumption in the ship navigation, thereby realizing the economic navigation. The invention adopts a state feedback control algorithm, so that the control parameters are easier to set and the control efficiency is higher.

Description

A ship heading controller based on event trigger mechanism and its control method

technical field

The invention relates to a course controller of a large ship whose selected ship model is a NOMOTO model, in particular to a ship course controller based on an event trigger mechanism.

Background technique

As an important performance index for evaluating ship course control strategies, high efficiency and energy saving have attracted widespread attention in recent years. As the core component of ship course control, the course controller determines the overall performance of ship course control. The heading controller has become an emerging research hotspot in the field of ship motion control. Most of the existing ship heading controllers have the following problems in the design process: most of them are designed based on the discrete-time control strategy with a fixed sampling frequency, and there are high-frequency state switching between the controller and the actuator, that is, the control signal is controlled at each sampling moment. In the actual sea navigation process, the sampling rate of the controller often depends on the sea environment, and the execution rate of the controller mostly depends on the state of the ship itself, that is, the ship's heading, coordinate position and speed. Therefore, the traditional discrete The time control method will not only increase the calculation burden of the controller, the wear and tear of the actuator and unnecessary energy consumption, but also shorten the service life of the controller. The efficiency and energy saving of the heading controller need to be further improved.

Contents of the invention

In order to solve the above-mentioned problems existing in the prior art, the present invention is to design an event-triggered ship course based on an event-triggered mechanism with less energy consumption, less computational burden, fewer execution times, and a longer service life, while achieving efficient control and avoiding component wear and tear. A controller and its control method.

In order to achieve the above object, the technical solution of the present invention is as follows: a ship heading controller based on an event trigger mechanism, including a reference module, a trigger module and a controlled module, and the trigger module includes a calculation unit, a comparison unit and an instruction unit, The controlled module includes a control unit, a digital-to-analog conversion unit, a PWM signal output unit, an actuator, a controlled unit, an analog-to-digital conversion unit and a data processing unit; The output end of the controlled unit in the control module is connected with the input end of the control unit in the controlled module;

The output end of the control unit is sequentially connected to the input end of the control unit after being connected in series with the digital-to-analog conversion unit, PWM signal output unit, actuator, controlled unit, analog-to-digital conversion unit and data processing unit, and the entire controlled module constitutes A closed-loop control system;

The input end of the calculation unit is respectively connected to the output end of the reference module and the output end of the controlled unit in the controlled module, and the output end of the calculation unit is connected to the input end of the control unit in the controlled module through the comparison unit and the instruction unit ;

The reference module transmits the obtained reference data to the trigger module;

The controlled unit feeds back the obtained real-time data to the trigger module and the analog-to-digital conversion unit;

The trigger module calculates the state deviation and trigger function between the controlled module and the reference module according to the reference data output by the reference module and the real-time data fed back by the controlled unit, and simultaneously judges and issues a trigger command;

The control unit, according to the trigger instruction issued by the trigger module, performs state feedback control adjustment and outputs a control signal according to the output data of the data processing unit;

The digital-to-analog conversion unit sends the control signal output by the control unit to the PWM signal output unit after digital-to-analog conversion;

The PWM signal output unit generates a corresponding PWM waveform according to the output data of the digital-to-analog conversion unit to control the actuator;

The executive mechanism converts the electric pulse signal into an angular displacement or a linear displacement according to the PWM waveform pulse, drives the steering device, and controls the course of the ship;

The analog-to-digital conversion unit performs analog-to-digital conversion on the feedback data of the controlled unit and sends it to the data processing unit;

The data processing unit compares the output data of the analog-to-digital conversion unit with the planned course, and outputs the control input signal of the control unit.

Further, the reference module and the controlled module have the same state space model, both are equipped with a state feedback digital signal conditioner, and the state feedback digital signal conditioner uses the same ship model with the same design parameters, Namely the NOMOTO model.

A ship heading controller based on an event trigger mechanism and a control method thereof, comprising the following steps:

1, reference module transmits the reference data that obtains to trigger module, and described reference data comprises under the given situation of plan heading P1, the reference heading data A1 of gyrocompass output, the reference yaw rate A2 of speed measuring instrument output and The reference rudder angle A3 output by the rudder angle indicator; in order to facilitate computer simulation and ship motion controller design, a linear ship motion mathematical model, namely the NOMOTO model, is used in the reference module, taking the servo mechanism of the steering gear into consideration, and expressed as The column vector composed of the reference data A1～A3 output by the reference module is the state variable x _r (t), and the overall state space model of the reference module is simplified as

y _r (t) = Cx _r (t) + Du _r (t)

in

Here, t represents the sampling time of the computer, and A, B, C and D represent the system matrix, input matrix, output matrix and state transition matrix of the reference module under the state space model respectively, and they are all designs related to the internal structure of the reference module Parameters, u _r (t) is the input of the reference module, here refers to the planned heading P1, y _r (t) is the output of the reference module, here refers to the reference heading A1 output by the reference module, K _s and T _s respectively Represents the time gain and time constant of the reference module, these two parameters are closely related to the gyration and tracking of the ship, T _E and K _E represent the steering gear time constant and steering gear control gain of the reference module, respectively;

II. The calculation unit in the trigger module calculates the state deviation θ(t) between the controlled module and the reference module and the trigger function V( θ(t)), the real-time data B1～B3 refers to the course B1, yaw rate B2 and rudder angle B3 output by the controlled unit in the controlled module under the given situation of the planned course P1;

θ(t)=x(t)-x _r (t)

That is, the state deviation between the controlled module and the reference module, where:

x(t)=[ψ(t)r(t)δ(t)] ^T

Represents the state variable of the controlled module, ψ(t), r(t), δ(t) represent heading B1, yaw rate B2 and rudder angle B3 respectively;

V(θ(t))＝θ(t) ^T Pθ(t)

is the trigger function, where P is the solution of the Lyapunov equation of the controlled module;

The comparison unit compares the trigger function V(θ(t)) and its threshold ρ at each sampling moment;

The command unit judges the update time of the control unit according to the comparison result of the comparison unit and gives a trigger command. Whenever the trigger function V(θ(t)) reaches the set threshold ρ, that is, when the trigger time is reached, the command unit sends The control unit issues an instruction to update the control signal, and when the trigger function V(θ(t)) does not reach the set threshold ρ, that is, when the trigger time is not reached, the instruction unit does not issue an update instruction to the control unit, and the output control of the control unit The signal will not be updated at this moment, and the control signal at the previous trigger moment will always remain unchanged;

III. The control unit performs state feedback adjustment on the output data of the data processing unit according to the trigger instruction issued by the trigger module and outputs a control signal. Since the closed-loop pole is the basis for evaluating the performance of the closed-loop system, the closed-loop pole of the controlled module is at frequency The position of the S-plane in the frequency domain is closely related to the stability and dynamic performance of the controlled module. Here, the closed-loop pole of the controlled module is arranged on the left half-plane of S in the frequency domain as the principle to complete the state feedback digital signal adjustment in the control unit. The basic design of the device, the specific adjustment method is

in, is the control signal output by the control unit in the controlled module, t _k is the trigger moment, that is, the moment when the trigger function V(θ(t)) reaches the set threshold ρ, k=1,2,3..., A, B and C The meaning and specific form of are the same as the reference module, they are also the design parameters of the controlled module, K is the feedback gain matrix, J is the correction matrix, ψ _m (t) is the planned course P1 of the controlled module;

The pole configuration principle is as follows: by feedbacking the three states of heading B1, yaw rate B2 and rudder angle B3 of the controlled unit in the controlled module, the closed-loop pole of the entire controlled module is configured on the left half of the S plane , considering the five aspects of adjustment time, overshoot, steady-state error, rise time, and delay time, adjust the position of the closed-loop pole of the controlled module on the left half plane of S to realize the design of the control performance of the controlled module;

The configuration method of the pole is: adjust the three parameters in the feedback gain matrix K=[K ₀ , K ₁ , K ₂ ] to realize the configuration of the position of the closed-loop pole of the controlled module, where K ₀ is the feedback gain of heading B1, and K ₁ is the feedback gain of the yaw rate B2, K ₂ is the feedback gain of the rudder angle B3, thus the output of the control unit is obtained In addition, according to the characteristics of the trigger control, It is updated only at the triggering time t _k , and maintains between two triggering times [t _k ,t _k+1 ) remain unchanged, i.e.

IV, the digital-to-analog conversion unit sends the control signal output by the control unit to the PWM signal output unit after digital-to-analog conversion;

V. The PWM signal output unit generates a corresponding PWM waveform according to the output data of the digital-to-analog conversion unit to control the actuator;

VI. The actuator converts the electrical pulse signal into angular displacement or linear displacement according to the PWM waveform pulse, drives the rudder device, and controls the ship's course;

VII, the controlled unit feeds back the state of the three ships, the course B1, the yaw rate B2, and the steering gear angle B3, to the trigger module and the analog-to-digital conversion unit in real time;

VIII, the analog-to-digital conversion unit sends the feedback data of the controlled unit to the data processing unit after analog-to-digital conversion;

IX. The data processing unit compares the output data of the analog-to-digital conversion unit with the planned heading, and gives the control input signal of the control unit.

Compared with the prior art, the present invention has the following beneficial effects:

1. By adopting the ship course controller based on the event trigger mechanism, the present invention not only reduces the calculation and update burden of the ship course control system on the control signal, avoids the high-frequency state switching of the ship steering device and the high-frequency friction of the control parts, At the same time, the energy consumption in the navigation of the ship is also reduced, thereby realizing economical navigation, which is also the biggest advantage of the course control method in the present invention;

2. The present invention can realize the convenient adjustment of heading control precision by adjusting the threshold ρ of the trigger function V(θ(t)); secondly, the three parameters K ₀ , K ₁ and K ₂ in the feedback gain matrix K are respectively related to the three parameters of the ship. Therefore, another advantage of this method compared with the traditional heading control method is that the physical meaning of the control parameters is more intuitive and clear, and the parameter setting is relatively simple and easy.

3. The control unit part of the controlled module of the present invention mainly adopts the state feedback control algorithm instead of the PID control algorithm. Compared with the PID control, the control parameters of this control method are easier to set and the control efficiency is higher. Secondly, the present invention adopts The control method of output reference is proposed, that is, the design of the control unit in the trigger module and the controlled module is carried out with reference to the navigation data of the reference module, so as to realize the purpose of economic navigation.

Description of drawings

Fig. 1 is a schematic structural diagram of an embodiment of the present invention.

Fig. 2 is a diagram of the simulation results of heading tracking of the reference module of the present invention.

Fig. 3 is a simulation result diagram of the heading tracking of the controlled module of the present invention.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings.

The ship course controller based on the event trigger mechanism of the present invention is shown in FIG. 1 , and the simulation results of its control performance verification are shown in FIG. 3 . The mathematical model of the ship heading is ψ _m represents the ideal system performance of the ship heading, that is, the planned heading P1, where ψ _r =15[sign(sin(2πt/500))+1] is the command input signal, its value varies from 0° to 30°, and the period It is 500 seconds. In the simulation process, the sampling time is selected as t _s =0.1 second, and the simulation time is selected as t=800 seconds. It can be seen that the number of triggers of the heading controller without the event trigger mechanism is 8000 times, and the control signal is carried out 8000 times of calculation and update, and 8000 times of state switching of the actuator.

From the simulation results in Figure 2-3, it can be seen that the ship heading controller and its control method based on the event-triggered mechanism can achieve better results than those without the trigger mechanism in terms of response speed, smoothness, output stability, and dynamic performance. At the same time, as shown in Table 1, the number of updates of the ship heading controller based on the event trigger mechanism is significantly reduced, and the threshold value ρ of the trigger function is very small, that is, the control accuracy is higher At this time, the number of updates of the controller still does not exceed 3000 times. Compared with the 8000 times of triggering of the heading controller without a trigger mechanism, the former is more energy-saving and efficient, which not only reduces the calculation burden of the system and the energy consumption of the ship during navigation, but also The number of updates of the control signal and the number of state switching of the actuator are reduced. It can be seen that the ship heading controller based on the event trigger mechanism has high control accuracy and strong practicability. At the same time, it has potential application value for realizing economical navigation.

Table 1 The update times of the ship heading controller based on the event trigger mechanism

The present invention adopts the method of state feedback pole configuration in the control unit, and designs a state feedback controller. Compared with the previous PID control method, the parameters of the course controller designed here are easier to set and the physical meaning is more intuitive and clear. Secondly, , referring to the reference module, a trigger mechanism and corresponding trigger module are designed to realize economic heading through trigger control; here, the number of triggers or the number of calculation updates of the control unit depends on whether the heading control performance of the ship meets the requirements and the conditions for stable sailing Whether it is satisfied or not, when the ship sails stably according to the given requirements, the control signal remains constant without calculation and update, thereby reducing the calculation burden of the controller, reducing the state switching of the actuator and unnecessary wear of parts, and saving energy. At the same time, the service life of the ship is extended, and economical sailing is finally realized.

The present invention is not limited to this embodiment, and any equivalent ideas or changes within the technical scope disclosed in the present invention are listed in the protection scope of the present invention.

Claims (3)

1. A ship course controller based on an event trigger mechanism is characterized in that: the device comprises a reference module, a triggering module and a controlled module, wherein the triggering module comprises a calculating unit, a comparing unit and an instruction unit, and the controlled module comprises a control unit, a digital-to-analog conversion unit, a PWM signal output unit, an executing mechanism, a controlled unit, an analog-to-digital conversion unit and a data processing unit; the trigger module is respectively connected with the output end of the reference module, the output end of the controlled unit in the controlled module and the input end of the control unit in the controlled module;

the output end of the control unit is connected with the digital-to-analog conversion unit, the PWM signal output unit, the actuating mechanism, the controlled unit, the analog-to-digital conversion unit and the data processing unit in series in sequence and then connected to the input end of the control unit, and the whole controlled module forms a closed-loop control system;

the input end of the computing unit is respectively connected with the output end of the reference module and the output end of the controlled unit in the controlled module, and the output end of the computing unit is connected to the input end of the control unit in the controlled module through the comparison unit and the instruction unit;

the reference module transmits the obtained reference data to the trigger module;

the controlled unit feeds back the obtained real-time data to the triggering module and the analog-to-digital conversion unit;

the triggering module calculates the state deviation and triggering function of the controlled module and the reference module according to the reference data output by the reference module and the real-time data fed back by the controlled unit, and judges and sends a triggering instruction at the same time;

the control unit performs state feedback control adjustment according to the trigger instruction sent by the trigger module and the output data of the data processing unit and outputs a control signal;

the digital-to-analog conversion unit is used for performing digital-to-analog conversion on the control signal output by the control unit and then sending the control signal to the PWM signal output unit;

the PWM signal output unit generates a corresponding PWM waveform according to the output data of the digital-to-analog conversion unit and controls the actuating mechanism;

the actuating mechanism converts the electric pulse signal into angular displacement or linear displacement according to the PWM waveform pulse, drives the steering device and controls the course of the ship;

the analog-to-digital conversion unit performs analog-to-digital conversion on the feedback data of the controlled unit and then sends the feedback data to the data processing unit;

and the data processing unit compares the output data of the analog-to-digital conversion unit with the planned course and outputs a control input signal of the control unit.

2. The ship heading controller based on the event trigger mechanism as claimed in claim 1, wherein: the reference module and the controlled module have the same state space model, both are provided with state feedback digital signal regulators, and the state feedback digital signal regulators use the same ship model with the same design parameters, namely a NOMOTO model.

3. A ship course controller based on an event trigger mechanism and a control method thereof are characterized in that: the method comprises the following steps:

I. the reference module transmits the obtained reference data to the trigger module, wherein the reference data comprises reference heading data A1 output by the electric compass, reference heading angular speed A2 output by the tachometer and reference rudder angle A3 output by the rudder angle indicator under the condition that the planned heading P1 is given; in order to facilitate computer simulation and design of a ship motion controller, a linear ship motion mathematical model, namely a NOMOTO model is used in a reference module, a steering engine servo mechanism is taken into consideration, and a column vector consisting of reference data A1-A3 output by the reference module is taken as a state variable x_r(t) simplifying the state space model of the entire reference module to

${\stackrel{\·}{x}}_r\left(t\right)={\mathrm{Ax}}_r\left(t\right)+{\mathrm{Bu}}_r\left(t\right)$

y_r(t)＝Cx_r(t)+Du_r(t)

Wherein

$A=\left[\begin{array}{ccc}0& 1& 0\\ 0& -\frac{1}{T_s}& \frac{K_s}{T_s}\\ 0& 0& -\frac{1}{T_E}\end{array}\right],B=\left[\begin{array}{c}0\\ 0\\ \frac{K_E}{T_E}\end{array}\right],C=\left[\begin{array}{ccc}1& 0& 0\end{array}\right],D=0$

Here, t represents the sampling time of the computer, A, B, C and D represent the system matrix, input matrix, output matrix and state transition matrix of the reference module under the state space model, which are the design parameters related to the internal structure of the reference module, respectively, u_r(t) is the input to the reference module, referred to herein as the planned heading P1, y_r(t) is the output of the reference module, which is referred to herein as the reference heading A1, K of the reference module output_sAnd T_sRespectively representing the time gain and time constant of the reference module, which are closely related to the gyrating and tracking properties of the ship, T_EAnd K_ERespectively representing a steering engine time constant and a steering engine control gain of the reference module;

II. The calculating unit in the triggering module calculates state deviation theta (t) and a triggering function V (theta (t)) of the controlled module and the reference module according to reference data A1-A3 output by the reference module and real-time data B1-B3 fed back by the controlled unit, wherein the real-time data B1-B3 refer to a heading B1, a heading angular speed B2 and a rudder angle B3 output by the controlled unit in the controlled module under the condition that a planned heading P1 is given;

θ(t)＝x(t)-x_r(t)

i.e. the state deviation of the controlled module from the reference module, wherein:

x(t)＝[ψ(t) r(t) (t)]^T

the state variables psi (t), r (t) and (t) representing the controlled module respectively represent a heading direction B1, a heading angular speed B2 and a rudder angle B3;

V(θ(t))＝θ(t)^TPθ(t)

is a trigger function, where P is the solution of the controlled module Lyapunov equation;

the comparison unit compares the trigger function V (theta (t)) and the threshold value rho thereof at each sampling moment;

the instruction unit judges the updating time of the control unit according to the comparison result of the comparison unit and gives a trigger instruction, when the trigger function V (theta (t)) reaches the set threshold value rho, namely the trigger time, the instruction unit sends a control signal updating instruction to the control unit, and when the trigger function V (theta (t)) does not reach the set threshold value rho, namely the trigger time, the instruction unit does not send the updating instruction to the control unit, the control signal output by the control unit is not updated at the time, and the control signal of the previous trigger time is always kept unchanged;

and III, the control unit performs state feedback regulation on output data of the data processing unit and outputs a control signal according to a trigger instruction sent by the trigger module, and the position of the closed-loop pole of the controlled module in an S plane in a frequency domain is closely related to the stability and the dynamic performance of the controlled module because the closed-loop pole is the basis for evaluating various performances of a closed-loop system, wherein the basic design of a state feedback digital signal regulator in the control unit is completed by using the principle that the closed-loop pole of the controlled module is configured in an S left half plane in the frequency domain, and the specific regulation method is that

Wherein,for control signals output by control units in the controlled module, t_kFor the triggering time, that is, the time when the triggering function V (θ (t)) reaches the set threshold ρ, K is 1,2,3 …, A, B and C, and the meaning and the specific form are the same as those of the reference module, which are also the design parameters of the controlled module, K is the feedback gain matrix, J is the correction matrix, ψ is_m(t) is the planned heading P1 for the controlled module;

the configuration principle of the extreme points is as follows: the method comprises the steps that three states of a heading B1, a heading angular velocity B2 and a rudder angle B3 of a controlled unit in a controlled module are fed back, a closed loop pole of the whole controlled module is configured on the left half part of an S plane, and the position of the closed loop pole of the controlled module on the left half plane of the S plane is adjusted to realize the design of the control performance of the controlled module in consideration of adjusting time, overshoot, steady-state error, rising time and delay time;

the configuration method of the pole comprises the following steps: adjusting feedback gain matrix K ═ K₀,K₁,K₂]The three parameters in (1) realize the configuration of the position of the closed loop pole of the controlled module, wherein K₀Feedback gain for heading B1, K₁For the feedback gain of yaw rate B2, K₂Is the feedback gain of the steering angle B3, thereby obtaining the output of the control unitIn addition, according to the characteristics of the trigger control,only at the triggering time t_kThe update is performed with two triggering times t_k,t_k+1) Is maintained betweenRemain unchanged, i.e.

IV, the digital-to-analog conversion unit performs digital-to-analog conversion on the control signal output by the control unit and then sends the control signal to the PWM signal output unit;

v, PWM the signal output unit generates corresponding PWM waveform according to the output data of the D/A conversion unit to control the actuator;

VI, the executing mechanism converts the electric pulse signal into angular displacement or linear displacement according to the PWM waveform pulse, drives the steering device and controls the ship course;

VII, the controlled unit feeds the states of three ships, namely a heading B1, a heading angular velocity B2 and a steering engine rudder angle B3, back to the triggering module and the analog-digital conversion unit in real time;

VIII, the analog-to-digital conversion unit performs analog-to-digital conversion on the feedback data of the controlled unit and then sends the feedback data to the data processing unit;

and IX, the data processing unit compares the output data of the analog-to-digital conversion unit with the planned heading and gives a control input signal of the control unit.