JPH0680097A - Attitude control method for underwater running body - Google Patents

Abstract

PURPOSE:To enable rapid attitude angle alteration in posture control of an underwater running body and also proper stability at a desired value. CONSTITUTION:An underwater running body is provided with a differentiator 1, a subtractor 5, a main rudder angle decision section 2 for deciding roughly a rudder angle, in the vicintity of an desired value in attitude control and a fine adjustment streerage speed decision section 3, an integrator 4 and an adder 6 for rapid decision of desired attitude angle and steerage speed command value decision for holding a desired value. A main rudder angle betam as an output of the main rudder angle decision section 2 and a fine adjustment rudder angle betas as the integration of an output of the fine adjustment steerange speed decision section are added together, so that a final rudder angle command beta is outputted to a steerage mechanism.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an attitude control method for an underwater vehicle, and more particularly to an attitude control method for an underwater vehicle that has a built-in pouring / drainage tank and controls the attitude of an underwater vehicle traveling underwater. Regarding

[0002]

2. Description of the Related Art Conventionally, any one of the methods shown in FIGS. 6A to 6C has been used as the attitude control method for an underwater vehicle such as a submarine ship.

FIG. 6A shows a general PID control method in which the attitude angle θ by the attitude angle sensor and the target attitude angle θc are input to obtain the steering angle command β.

FIG. 6B shows the posture angle θ as the target posture angle θc.
To attitude angle deviation Δθ (= θc−θ) and attitude angular velocity dθ
/ Dt is calculated, fuzzy inference determined by the created control rule and membership function is performed, and the steering angle itself to be determined is also determined.

FIG. 6 (C) uses the same input as in FIG. 6 (B), and instead of the rudder angle to be taken, the fuzzy inference is performed on the increment value such as "increase by several degrees" or "decrease by several degrees". The steering angle to be taken is determined by integrating the output at time t.

[0006]

Each of the conventional attitude control systems for underwater vehicles shown in FIG. 6 has the following problems.

The PID control system shown in FIG. 6A basically has a proportional gain Kp, when the posture angle is horizontal.
Since the integral gain Ki and the differential gain Kd are determined, the optimum gain is not obtained when controlling a large attitude angle.
In the worst case, there is a problem that the control becomes impossible.

This is because each gain of the PID control system is determined on the assumption that the controlled object is linear, and the assumption at the time of design is not satisfied due to the nonlinearity at a large attitude angle. is there.

In the fuzzy control system shown in FIG. 6B, if the control rule and membership function are well determined, the target value can be reached quickly. However, underwater navigation when a large attitude angle is taken. It is difficult to determine the rudder angle for canceling the effect of the restoring moment acting on the running body by a rule, and the rudder angle for canceling the restoring moment largely changes depending on the target attitude angle. Deviation) is large.

Further, if there is a front-rear unbalance moment that changes depending on the tank liquid amount of the water pouring / draining tank of the underwater vehicle, it is necessary to steer to cancel this front-rear unbalance moment, and the rudder angle is the tank state or There is a problem that it is difficult to make a rule because it changes depending on speed.

Further, the method shown in FIG. 6C is a method considering the influence of the restoring moment and the unbalance moment described above. However, this method is rather used when maintaining the posture. Is effective, but when designing with parameters for maintaining the posture (membership function etc.), there was a problem that the response becomes slow when changing the posture angle.

On the contrary, if the design is made with the parameters for changing the posture angle, the initial arrival near the target value becomes faster, but it becomes oscillatory near the target value and the stability for holding the target deteriorates. There was a problem. That is, in the case of FIG. 6C, there is a problem that it is difficult to determine a parameter that simultaneously satisfies the responsiveness and the steady characteristic.

The object of the present invention is to solve the above-mentioned problems,
Providing an attitude control method for underwater vehicles that can quickly reach the target attitude angle and can reduce the steady-state deviation to zero even if the attitude angle is large, and the control algorithm is easy to develop and maintainability is high. To do.

[0014]

The attitude control system for an underwater vehicle according to the present invention includes a attitude angle change rudder angle inference for fuzzy inference of a rudder angle corresponding to a change in the attitude angle of the underwater vehicle, and a target attitude angle. To defeat the rudder in the opposite direction to prevent overshoot before reaching the target angle, and to deduce the rudder angle for fuzzy inference of the rudder rudder and the attitude angle holding rudder angle for fuzzy inference of the rudder angle to roughly maintain the attitude angle. The inference results of the three types of steering amounts obtained by the three types of inference of inference are output in the form of membership functions, and these inference results are integrated into one membership function and then defuzzified. The main rudder angle determining means for determining the main rudder angle as the steering amount, and the fine rudder for correcting the deviation from the target value when the attitude angle is almost the target value to give the required rudder angle command. Adjustment Angle a as input and attitude angle deviation and speed by adding to the main steering angle determined by the fuzzy inference has a configuration in which a fine adjustment steering angle determining means for the steering angle command.

In the attitude control system for an underwater vehicle of the present invention, the attitude angle rudder angle inference is based on the difference between the desired target attitude angle of the underwater vehicle and the attitude angle obtained by the attitude angle sensor. The deviation and the speed acquired by the speed sensor are inferred as inputs, and the rudder steering angle inference and the attitude angle holding rudder angle inference are the attitude obtained from the attitude angle deviation and the attitude angle of the underwater vehicle. The configuration is such that the inference is made with the angular velocity and the input.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention. In the embodiment shown in FIG. 1, a differentiator 1, a subtractor 5 and a main steering angle determining unit 2 as main steering angle determining means for determining a main steering angle as a steering amount, and a steering amount are finely adjusted. A fine adjustment steering speed determination unit 3, an integrator 4 and an adder 6 are provided as fine adjustment steering angle determination means for determining a fine adjustment steering angle for adding the main steering angle to the main steering angle.

Next, the operation of this embodiment will be described.

In the embodiment shown in FIG. 1, the attitude angle θ acquired from the attitude angle sensor of the underwater vehicle, the speed V acquired from the speed sensor, and the target attitude angle θc are input to control the attitude angle. The steering angle command β given to the steering system is output.

The attitude angle θ is input to the differentiator 1 to obtain the attitude angular velocity dθ / dt, and the target attitude angle θc
It is used to calculate the attitude angle deviation Δθ (= θc −θ) in combination with.

Posture angular velocity dθ / obtained by differentiator 1
dt is input to the main rudder angle determining unit 2 to determine the main rudder angle βm as the rudder angle together with the attitude angle deviation Δθ and the speed V. Further, the attitude angle deviation Δθ and the speed V are used to determine the fine adjustment steering speed dβs / dt necessary for obtaining the fine adjustment angle for performing the fine adjustment in the vicinity of the target attitude angle. Input to 3.

The fine adjustment steering speed dβs / dt output from the fine adjustment steering speed determination unit 3 is input to the integrator 4, and the fine adjustment steering angle βs is output by the integration processing.

The finely adjusted rudder angle βs is added to the main rudder angle βm output from the main rudder angle determiner 2 to obtain the final rudder angle command β.
(= Βm + βs) is obtained.

Next, the operations of the main rudder angle determination unit 2 and the fine adjustment steering speed determination unit 3 which are the main parts of the present invention will be described.

The main rudder angle determining section 2 is a part for deciding the main rudder angle for roughly approaching the target attitude angle when the amount of change in the attitude angle is large, and corresponds to, for example, an operation in which a person roughly performs steering. To do.

The main rudder angle determination unit 2 is arranged to change the attitude angle deviation Δθ,
The main steering angle βm is determined by fuzzy inference using the posture angular velocity dθ / dt and the speed data V as input values.

As shown in FIG. 2, the main rudder angle determining unit 2 approaches the target attitude angle to some extent with the attitude angle changing rudder angle inferring unit 7 which fuzzy infers the rudder angle corresponding to the attitude angle change. Corresponding to the case where the target rudder angle inference unit 8 for fuzzy reasoning of the rudder angle corresponding to the case where the rudder is steered in the opposite direction to prevent the overshooting against the target attitude angle and the target attitude angle is held The steering angle inference unit 9 for inferring the steering amount is composed of three kinds of steering angle inference units, and the inference result of the steering amount corresponding to each scene is expressed in the form of a membership function (hereinafter referred to as MF). Output.

These output conclusions MF are output to the conclusion integrating unit 10 and are combined into one conclusion MF.

The conclusion MF put together into one is an MF that represents the final steering angle inference result in the main steering angle determination unit 2 and cannot be used for control as it is, so it is input to the defuzzification unit 11. After the center of gravity is calculated, the main steering angle β
Converted to m and output.

The fine adjustment steering speed determiner 3 determines the fine adjustment steering speed for obtaining the fine adjustment angle for correcting the deviation from the target value when the posture angle is almost the target value. As shown in FIG. 4, using the attitude angle deviation Δθ and the speed V as inputs, the fine adjustment steering speed dβs / dt is fuzzy inferred by the fine adjustment steering speed inference unit 12 as in the main steering angle determination unit 3, and the conclusions are integrated. After the conclusions are integrated by the phasing unit 13, the defuzzification unit 14 calculates and calculates the center of gravity. However, the rules for inference are different.

Next, the rules of each inference unit will be described.

Examples of the rules of the main steering angle determination unit 2 are shown in FIGS. 3 (A) to 3 (D). In addition, the fine adjustment steering speed inference unit 3
An example of the rule is shown in FIG.

FIG. 3A shows an example of a posture angle changing rudder angle inference rule, where the number of rules N1 is 11. See also FIG.
(B) shows an example of a rudder rudder angle inference rule.
2 is 4. Further, FIG. 3C shows an example of the attitude angle holding steering angle inference rule, and the rule number N3 is 5.
Further, (D) of FIG. 3 shows the meaning of the L level used in (A) to (C) of FIG.

Now, the inference rules will be described by taking, for example, FIG. 1-No. 4 indicates the following contents, respectively.

No. 1: IFΔθ = PM and dθ
/ Dt = PL, THEN βm = NS (If the attitude angle deviation is positive and medium and the attitude angular velocity is positively large, make the main steering angle small and negative.) Or No. 2: IFΔθ = NM and dθ / dt =
NL, THEN βm = PS (If the attitude angle deviation is negative and medium and the attitude angular velocity is negative, set the main rudder angle small and positive.) Or No. 3: IFΔθ = PM and dθ / dt =
PM, THEN βm = ZR (If the attitude angle deviation is positive and medium and the attitude angular velocity is positive and medium, set the main steering angle to almost 0.) or No. 4: IFΔθ = NM and dθ / dt =
NM, THEN βm = ZR (If the attitude angle deviation is negative and medium and the attitude angular velocity is negative and medium, set the main steering angle to approximately 0.) The same applies to the rules of other inference units including FIG. Therefore, detailed description of each item is omitted.

[0036]

As described above, according to the present invention, it is possible to quickly reach the vicinity of the target attitude angle by determining the main rudder angle for determining the rough rudder angle. By performing the above, since there is a command to turn the steering until the posture angle deviation disappears even if the posture angle is large, the steady-state deviation can be made zero.

Further, since the fuzzy inference is used for determining the main steering angle and the fine adjustment steering angle, the know-how about steering can be easily incorporated in the language expression, and the control algorithm can be easily developed and maintainability is high. There is an effect that.

[Brief description of drawings]

FIG. 1 is a flock diagram of an embodiment of the present invention.

FIG. 2 is a block diagram of a main steering angle determination unit 2 in FIG.

FIG. 3 is a diagram showing an inference rule example of a posture angle change rudder angle inference unit 7 in FIG. 2 (A), a diagram showing an inference rule example of a steering rudder angle inference unit 8 in FIG. It is a figure (C) which shows the example of the inference rule of the part 9, and a figure (D) which shows and shows the label content.

FIG. 4 is a block diagram of a fine adjustment steering speed determination unit 3 in FIG.

5 is a diagram showing an inference rule example of a fine adjustment steering speed determination unit 3 in FIG.

FIG. 6 is a functional block diagram (A) showing a first example of a conventional attitude control system, a functional block diagram (B) showing a second example, and a functional block diagram (C) showing a third example.

[Explanation of symbols]

 1 Differentiator 2 Main rudder angle determination unit 3 Fine adjustment steering speed determination unit 4 Integrator 5 Subtractor 6 Adder 7 Attitude angle change rudder angle inference unit 8 Target rudder angle inference unit 9 Attitude angle holding rudder angle inference unit 10 Conclusion Integration part 11 Defuzzification part 12 Fine adjustment steering speed inference part 13 Conclusion Integration part 14 Defuzzification part

Claims (2)

[Claims] 1. A posture angle change rudder angle inference for fuzzy inference of a rudder angle corresponding to a change in posture angle of an underwater vehicle, and steering in the opposite direction to prevent overshoot before reaching a target posture angle. Inference results of three types of steering amounts obtained by three types of fuzzy inference: a rudder rudder angle inference for fuzzy inference of a rudder and an attitude angle holding rudder angle inference for fuzzy inference of a rudder angle for roughly maintaining the attitude angle Are output in the form of membership functions, and these inference results are integrated into one membership function and then defuzzified to determine the main steering angle as the steering amount. The determination means and the finely adjusted rudder angle for correcting the deviation from the target value to give the required rudder angle command when the attitude angle is almost at the target value are obtained by fuzzy reasoning by inputting the attitude angle deviation and the speed. An attitude control system for an underwater vehicle, comprising: a finely adjusted rudder angle determining means for obtaining a rudder angle command by adding to the main rudder angle. 2. The attitude angle rudder angle inference inputs the attitude angle deviation of the difference between the target attitude angle of the underwater vehicle and the attitude angle acquired by the attitude angle sensor, and the speed acquired by the speed sensor. And that the rudder rudder angle inference and the attitude angle holding rudder angle inference are inferred with the attitude angle deviation of the underwater vehicle and the attitude angular velocity obtained from the attitude angle as inputs. The attitude control system for an underwater vehicle according to claim 1, which is characterized in that.