JPS6076499A - Method and device for controlling pitch of variable pitch propeller - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] This invention relates to pitch control of a variable pitch propeller,
This invention relates to pitch control of a variable pitch propeller that continuously maximizes propeller operating efficiency and continuously controls both the blade angle and the propeller rotation speed according to the operational status of the propeller.

Generally, aircraft propellers, helicopter rotors,
By adjusting the pitch of the rotor blades of marine propellers, industrial fans, and wind turbines, thrust, absorbed power, air volume, etc. can be easily controlled, and the performance characteristics can be significantly improved.

For example, in the case of aircraft, automatic pitch control of a variable pitch propeller includes constant speed control, which is a control method that automatically selects the blade angle to obtain a set constant rotation speed regardless of the applied power, or A typical example is beta (β) control, which is a control method that changes the thrust by manually changing the blade angle directly during ground travel.

This constant speed control method selects the set propeller rotation speed to be optimal in cruising conditions, so in operating conditions other than cruising conditions, such as during takeoff and climb, optimal propeller control is not necessarily carried out in terms of efficiency. It's hard to say that there are. For example, in the case of constant speed control, engine power and propeller absorption power are balanced by changing the blade angle in response to changes in the mechanism or engine power.
Optimum propeller efficiency can only be achieved under cruising conditions, which are the design flight conditions.

Furthermore, from the standpoint of resource conservation, aircraft, engines, etc. with excellent energy efficiency are desired in aircraft, and high-speed propellers with excellent energy efficiency are attracting particular attention, and various studies are being conducted. From this point of view as well, efficient propeller control is desperately needed.

Furthermore, the propeller control system must have a sufficiently stable transient response even under harsh conditions, and for this reason, the pitch conversion mechanism, which is the main element of propeller control, and its control must be maintained. This requires a control system that fully considers the detailed characteristics of the aircraft, engine, and propeller and their interrelationships, but until now, no pitch control for variable pitch propellers has been studied from this perspective. .

In view of the above-mentioned current situation, this invention aims at adaptive control of a propeller that realizes optimization of propeller operating conditions according to arbitrary flight conditions, and also aims at automatic pitch control that maximizes the operating efficiency of a variable pitch propeller. For the purpose of automatic pitch control, which controls the propeller to always operate at maximum efficiency in real-time response to changes in aircraft operating conditions, and to maintain sufficiently stable transients under any conditions. Aiming at a propeller control system with response,
Furthermore, the aim is automatic pitch control that can also control the multi-functions required of propellers, such as feathering and reversing.

That is, this invention calculates the optimal propeller operating conditions and propeller rotation speed (Nset) from performance data of a variable pitch propeller set in advance, based on the Matsuha number, altitude, total atmospheric pressure, and engine shaft output data during operation.
and the blade angle (βset), and further compare the current blade angle (β) and propeller rotation speed (N) to control the variable pitch mechanism and engine output to optimal propeller operating conditions. -N composite control is a pitch control method for a variable pitch propeller.

The present invention also provides a pitch control method for a variable pitch propeller, characterized in that β-N combined control and β direct control are selected by the pilot's selection. Temperature gauge, blade angle detector, propeller rotation speed detector, Matsuha number, altitude, full atmospheric air data, engine control device that controls output based on pilot commands and preset program charts, and variable pitch propeller. A means of storing propeller maximum efficiency operating conditions based on performance data of the engine control device, altitude, and total atmospheric temperature.

The propeller rotation speed (N
set) and the blade angle (βset); a propeller rotation speed correcting means for controlling the current propeller rotation speed according to the above-mentioned optimum propeller rotation speed (Nset); pitch correction means for controlling the blade angle of the propeller, and the blade angle and propeller rotation speed are continuously controlled based on the air data and engine shaft output data so as to always maintain optimum propeller operating conditions. This is a pitch control M device for a variable pinch propeller.

Specifically, the control device according to the present invention takes into account the pitch conversion mechanism and its control, which are the main elements of propeller control, and the detailed characteristics of the aircraft, engine, and propeller, and the interrelationships thereof, and uses a computer to This is a control device that integrates the control system between the propeller, the aircraft, and the engine, and maximizes the operational efficiency of the propeller so that it always operates at maximum efficiency in response to changes in the operating conditions of the aircraft in real time. By forming a data link with the flight controller, engine controller (FADEC), and air data computer for Matsuha's number, altitude, and atmosphere, and grasping the flight status in real time and combining it with the propeller performance data in memory, The propeller rotation speed is continuously controlled to find the optimum propeller rotation speed (N -5et), and the actual propeller rotation speed and blade angle obtained from the sensor are fed back to the computer, and the pitch, that is, the blade angle, is controlled via the actuator. The angle (β) is controlled to continuously maximize the operating efficiency of the propeller.

As described above, this invention performs β-N composite control, which is adaptive control, when controlling propeller efficiency, and since the propeller rotation speed is controlled to change, it is premised on the adoption of a free turbine engine.

In this invention, the speedometer, altimeter, and atmospheric thermometer are used to obtain air data indicating the flight condition of the aircraft, and are essential for determining the optimal operating conditions of the variable pitch propeller. It is also advisable to centrally process this data using one device.

The blade angle detector and the propeller rotation speed detector are essential for obtaining the actual blade angle per rotation speed and compensating it by comparing it with the calculated optimum value, but the configuration of the detector is based on the known Any device can be used, for example, a magnetic or optical encoder or tacho generator can be used to determine the propeller rotation speed, and a magnetic or optical absolute encoder can be used to determine the blade angle.

The engine control device performs output control based on air data, pilot commands, and preset program charts. Various known control devices can be used, and the rotation speed during operation is adjusted to the optimum propeller rotation speed set by the calculation means. The propeller rotation speed correction means for controlling the engine may be arranged within this engine control device.

The propeller maximum efficiency operating conditions shall be based on the theoretical and actual performance data of the variable pitch propeller, as well as the performance and characteristics of the engine used, and shall be taken into consideration to fully fulfill the various functions required of the aircraft and propeller. Based on calculations and experiments, we have determined the conditions under which the operational efficiency of the variable pitch propeller is always maximized under various aircraft running and flight conditions, such as taxiing, take-off, climbing, cruising, maximum level flight, approach, and reverse. , is set in advance,
Such conditions need to be stored in storage means that is the same as or separate from the calculation means.

The means for calculating the optimum propeller operating conditions is the Matsuha number from the engine control device or from a separate device.

The propeller rotation speed (Nset) and the blade angle (
βset ), and the calculation means may be of any type, configuration, or device.

Propeller rotation speed correction means for controlling the current propeller rotation speed according to the optimum propeller rotation speed (Nset);
The pitch correction means for controlling the blade angle during operation according to the above-mentioned optimum blade angle (βset) may be configured as a separate device for feedback control or may be the same computer, for example, correcting the propeller rotation speed. Various configurations are available, such as correction of the blade angle within the engine control device or signal control to the servo motor drive variable pitch mechanism. Based on the above air data and engine shaft output data, the optimum propeller operating conditions are always maintained. Any configuration that can continuously control the blade angle and propeller rotation speed is sufficient.

The present invention will be described in detail below based on a flowchart showing pitch control of a variable pitch propeller according to the present invention shown in FIG. 1 of the embodiment.

Here, an example will be described in which a propeller control unit (PCU) is used, which incorporates a storage means for the propeller maximum efficiency operating conditions, a calculation means for the optimum propeller operating conditions, and a correction means for the propeller rotation speed and blade angle.

The Matsuha number (Mn), altitude (H), and total atmospheric height ('C) are input to the air data computer from each measuring instrument, and the air data is input to the engine control (e.g.
FADEC;full au-hority di
digital electronic Control+
) is output.

The FADEC calculates engine control parameters, feeds back actual engine output, and controls the output via an actuator. In addition, in the cockbit, output control is performed by a power setting command according to the setting angle of the power lever operated by the pilot, and the PCU
Output control is performed according to the thrust data and the optimum propeller rotation speed signal based on the propeller rotation speed correction command. Also,
Needless to say, the cockbit displays the control status by FADEC, thrust, propeller rotation speed, air data, etc.

The PCU obtains information on the Matsuha number (Mn), altitude (H), total atmospheric pressure (°C), and engine shaft power (E, 5HP) from the air data computer on the aircraft side through FADEC. The memory circuit contains various information about the aircraft, taking into account the theoretical and actual performance data of the variable pitch propeller, the performance and characteristics of the engine used, and the various functions required of the aircraft and propeller. driving and flight conditions, i.e.
Based on calculations and experiments, the propeller maximum efficiency operating conditions are stored in advance to determine the conditions under which the operating efficiency of the variable pitch propeller is always at its maximum during taxiing, take-off, climbing, cruising, maximum level flight, approach, reverse, etc. Based on this condition and the above information, the propeller rotation speed (N) and blade angle (β), which are the optimal propeller operating conditions during operation, are calculated, and the current blade angle (β signal) determined by the blade angle detector is calculated. ) and the current propeller rotation speed determined by the propeller rotation speed detector (
N signal) is fed back and compared with the calculated optimum conditions, and the control correction signals Thrust and propeller rotation speed (N) are output to the FADEC and Cockbit display system. Target blade angle (
βset ) is output to the servo motor driver, which is the actuator of the variable pitch mechanism.

12- Also, the PCU receives the feathering command from the pilot,
It is configured to be able to immediately control the output to the FADEC and variable pitch mechanism when an aircraft function command is issued, such as a reverse command. It also has a limiter that checks and prevents overspeed, and controls the control status of the PCU. It is also configured to self-diagnose and display it on the cockbit.

The above control system determines the optimal propeller operating conditions and propeller rotation speed (N-set) based on the performance data of the variable pitch propeller set in advance, based on the Matsuha number, altitude, total atmospheric pressure, and engine shaft output data during operation. Calculate the blade angle (βset) and further calculate the current blade angle (
By comparing the variable pitch mechanism and engine output to the optimum propeller operating conditions by comparing the The propeller can always operate at maximum efficiency by responding to changes in real time.

Next, in the propeller control system described above, a second control block diagram for realizing β-N composite control will be described.
This will be explained based on the diagram.

The PCU contains Matsuha number (Mn) as flight status information.
, total atmosphere (℃), altitude (H) 1 mechanism (■), engine shaft output (ES) IP) are input, and based on this, the optimal propeller rotation speed (Nset), efficiency (η), and optimal blade angle are input. (βset) is calculated, the propeller rotation speed of the controlled object detected by the detector is sampled with an appropriately selected sample width, and fed back into the digital filter as a discrete time series, and the target propeller rotation speed (
A manipulated variable series is output for each sample width based on the deviation from The propeller rotation speed changes as the blade angle changes and is controlled to the target value.

In Figure 2, PNP is absorbed horsepower, ΔM is torque, ω
is angular velocity, n is rps, N is r4, Wf is fuel flow, J is advance radio, Thrust is thrust, DR
AG indicates aircraft resistance.

The propeller control using the β-N composite control described in detail above allows direct β control and β-N composite control to be freely selected, as shown in the propeller control mode selection flowchart shown in Figure 3. Various required functions, feathering, pitch lock, reverse,
It is also possible to create a propeller control system that takes into consideration the selection of factors such as the above and the response in the event of failure, thereby achieving safety and high efficiency under all operating conditions.

Next, in order to evaluate the effect of propeller control using β-N combined control according to the present invention, we will examine the propeller operating conditions of conventional constant speed control and β-N combined control for a current turboprop engine (63E 6O-19). A comparison was made. The flight conditions at this time were: altitude 0.5000ft, 10
000ft, 15000ft, mechanism 50-160m, engine output 25001-IP.

The obtained results are shown in the propeller operating state comparison in FIG. 4 and the propeller efficiency comparison in FIGS. 5 and 6. Figure 4 shows
The horizontal axis represents the advance radio, and the vertical axis represents the power coefficient, and the operational states of the propellers are plotted and compared in a group of propeller efficiency curves.

Figures 5 and 6 show the mechanism on the horizontal axis and the propeller efficiency on the vertical axis. In the cruising range, there is no difference in efficiency between either control method, but in the low speed range, the β-N combined control method It can be seen that the propeller efficiency is up to 5% higher. It has been reported that the area other than the cruise area in a flight mission accounts for about 32% for a 475 nautical mile mission and about 12% for a 1500 nautical mile mission, so the β-N combined control method is highly effective for short-range missions.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a flow chart showing pitch control of a variable pitch propeller according to the present invention, and FIG. 2 is a block diagram showing digital control according to the present invention. FIG. 3 is a flowchart showing propeller control mode selection in which β-N composite control according to the present invention is selectable. FIG. 4 is a graph comparing propeller operating conditions between conventional constant speed control and β-N combined control according to the present invention, in which the horizontal axis shows the advance radio and the vertical axis shows the power coefficient. Figures 5 and 6 are graphs comparing propeller efficiency. The horizontal axis shows the mechanism and the vertical axis shows efficiency. In the graphs, ○ is for β-N combined control, and ★ is for conventional constant speed control. In the case of control,
Figure 5 is for altitude O. Figure 6 shows the case at an altitude of 5000ft. Applicant Japan Aerospace Industries Association Applicant Sumitomo Precision Industries Co., Ltd.

Claims (1)

[Claims] 1. Optimum propeller operating conditions, propeller rotation speed (Nset) and blades are determined from performance data of a variable pitch propeller set in advance, based on data on the Matsuha number, altitude, full atmosphere, and engine shaft output during operation. The variable pitch mechanism is characterized in that the angle (βset) is calculated and further compared with the current blade angle (β) and propeller rotation speed (N) to control the variable pitch mechanism and propeller rotation speed to optimal propeller operating conditions. Propeller pitch control method. 2. Optimal propeller operating conditions, propeller rotation speed ( Nset>
The blade angle (βset) is calculated, and compared with the current blade angle (β) and propeller rotation speed (N), it is possible to select the variable pitch mechanism and the control that controls the propeller rotation speed for the optimal propeller operating conditions. A pitch control method for a variable pitch propeller, characterized in that: 3 Speedometer, altimeter, atmospheric wetness meter, blade angle detector, propeller rotation speed detector, Matsuha number, altitude,
An engine control device that performs output control based on air data of the entire atmosphere, pilot commands, and a preset program chart, storage means for maximum efficiency operating conditions based on performance data of the variable pitch propeller, and a Matsuha number from the engine control device. a calculation means for calculating the propeller rotation speed (Nset) and blade angle (βset) of the optimum propeller operating condition based on the altitude, total atmospheric temperature, engine shaft output data and the maximum efficiency operating condition of the propeller; and the above-mentioned optimum propeller rotation. The propeller rotation speed correction means controls the current propeller rotation speed according to the number (Nset), and the pitch correction means controls the current blade angle according to the above-mentioned optimum blade angle (βset). A pitch control device for a variable pitch propeller that continuously controls the blade angle and propeller rotation speed based on export force data to always maintain optimal propeller operating conditions.