RU2152637C1 - Motion control system for unmanned flying vehicle - Google Patents

Abstract

FIELD: automatic control systems. SUBSTANCE: each control channel of proposed control system includes autopilot, amplifier, control actuator, aerodynamic control member and AND logic gate. Each control channel is provided with additional control actuator and gas- dynamic control member connected in series; control channels are also provided with fault location unit. When fault is revealed by fault location unit, additional control actuator is connected, thus keeping the flying vehicle in kinematic trajectory of flight. EFFECT: enhanced reliability of keeping the flying vehicle in kinematic trajectory of flight. 2 dwg

Description

 The invention relates to the field of designing unmanned aerial vehicles having motion control systems with aerodynamic controls (rudders) and operating in abnormal operating conditions.

 It can be used in unmanned aerial vehicles operating in conditions of increased probability of failure of aerodynamic controls.

 The failure of the aerodynamic control means either its fixation in a certain position, regardless of the control signal, or its breakdown. Locking the steering wheel can be caused, for example, by a break in the communication line between the power steering and the steering gear. Damage to the steering wheel may occur due to its mechanical damage. By fault tolerance (or survivability) is meant the ability of the system to preserve some defining functions, with the possible complete or partial loss of other functions that characterize the operational state of the system (Ryabinin I.A. Main problems of survivability of technical systems. - L., Naval Academy, 1983 city, 27 pp.).

 Known control systems for the movement of an unmanned aerial vehicle using rudder-type rudders. Closest to the technical nature of the claimed device is the motion control system of an unmanned aerial vehicle US N 3807666 (B 64 C 13/18, 04/30/1974), selected as a prototype.

 Steering wheels belong to the aerodynamic control elements of the aircraft. The steering wheel is a metal plate of a certain shape, attached at one end to the axis of the steering gear. The drive is used to rotate the steering wheel in a neutral position. The signal for controlling the drive is supplied from an autopilot (or on-board digital computer complex), which is entrusted with the functions of controlling the movement of an unmanned aerial vehicle and stabilizing its position in space. The signal from the autopilot to the steering gear passes through the amplifier to bring it to the required power.

 The motion control system located on the unmanned aerial vehicle 1 (see Fig. 1) contains a serially connected amplifier 2, a steering gear 3 and an aerodynamic control element 4. A signal to rotate the aircraft at a certain angle in one of the stabilization planes is supplied from the corresponding output autopilot 5. The autopilot is designed to stabilize the device in space along three channels: yaw, pitch and roll. The motion control system includes all three channels. For simplicity of presentation and certainty, we will consider for consideration one of the channels of the motion control system — the pitch channel.

 At the input of the control system of the apparatus’s movement along the pitch channel, namely, at the input of the amplifier 2, a signal is output from the autopilot 5 output, designed to rotate the apparatus along the pitch angle. The signal is amplified by power in the amplifier 2 and fed to the steering gear 3. The steering gear, being mechanically connected to the aerodynamic control 4, turns it around at a given angle. The axis of the steering wheel passes through the body of the unmanned aerial vehicle 1. Deviation of the steering wheel at a certain angle causes the unmanned aerial vehicle 1 to turn in the direction of deviation of the steering wheel.

This traditional unmanned aerial vehicle movement control system has the following significant disadvantages due to its low fault tolerance, in particular, to mechanical damage:
1. The impact of mechanical damage on the steering organ is manifested in the form of a partial or complete loss of the steering surface of the steering wheel. A change in the area of the damaged rudder, for example, elevator, affects the appearance of disturbing moments in roll, yaw and pitch. The last moment, as a rule, cannot be compensated by the action of another fixed rudder, providing control over the given control channel of an unmanned aerial vehicle. Parry of the disturbing moment along the roll is not always provided by the aircraft stabilization system due to changes in the aerodynamic characteristics of the damaged rudder.

 2. In addition, the appearance of disturbance along one of the stabilization channels of an unmanned aerial vehicle (in this case, pitch) leads to a turn of the rocket in the stabilization plane in which the control is violated. Being uncompensated, the error in controlling an unmanned aerial vehicle in this channel increases even more, which leads to a positive feedback effect. As a result, for example, an unmanned aerial vehicle flying low above the sea surface is brought in without fulfilling the assigned task.

 3. When solving the problem of increasing the survivability of the steering control elements of the movement of an unmanned aerial vehicle, a need arises for solving a technical contradiction. The essence of the contradiction is as follows. On the one hand, the steering wheel must be present in order to control the movement of the unmanned aerial vehicle. On the other hand, the steering wheel should not be, since the presence of the steering wheel is a prerequisite for its possible mechanical damage and breakdowns.

 The technical result consists in increasing the likelihood of keeping an unmanned aerial vehicle on the kinematic flight path by parrying the change in the aerodynamic characteristics of the rudder that arose due to its damage.

 The specified result is achieved by connecting additionally to each control channel of the system to the output of the amplifier through the first input of the logical element And and its output of the serial connection of the additional steering gear and gas-dynamic control. At the same time, the input of the auxiliary steering drive is connected to the output of the logical element AND, the output of which is connected to the input of the gas-dynamic control element. The input of the aerodynamic organ damage identification unit is connected to this body, and the output of the identification unit is connected to the autopilot input. The second output of the autopilot is connected to the second input of the logical element I.

 The resolution of this contradiction is achieved by introducing into each control channel an additional steering drive system and a gas-dynamic (jet) control. In this case, the jet, on the one hand, performs the functions of a motion control body, and, on the other hand, the jet is not subject to destruction from mechanical damage. Advantages and disadvantages of the system of jet control of movement and stabilization of an unmanned aerial vehicle are given in [2, clause 5.3. "Methods of connecting control moments", p. 50-51].

 The change in the surface of the aerodynamic control due to damage is recorded, and the value of the remaining undamaged wing area is measured using the input damage identification unit. Namely, in each channel of the unmanned aerial vehicle’s motion control system, a series-connected steering gear and a gas-dynamic control are additionally installed. The damage identification block of the aerodynamic control element is mechanically connected with this body and continuously generates an electrical signal about the size of the fixed rudder area, which is fed to the autopilot input to which this control channel corresponds.

 In autopilot, the intact rudder area is compared with a certain threshold value. When the remaining intact rudder area exceeds the stability threshold of the aircraft, the autopilot generates a command to switch to the backup control unit. The command to activate the backup unit of the motion control system is supplied from the additional output of the autopilot through the AND gate, and the signal from the amplifier output is sent to the other input of the specified element.

 Comparative analysis with the prototype shows that the inventive device is characterized by the presence of new units - an additional steering gear with a gas-dynamic control, a logical element And, and an identification block of damage to the aerodynamic control. Thus, the claimed device meets the criterion of "novelty."

 Comparison of the proposed solution with other technical solutions shows that the introduction into the inventive device of the damage identification unit of the aerodynamic control element necessary for measuring the intact area of this body, as well as additional series-connected steering gear with the gas-dynamic control element, along with the logical element And, through which the autopilot includes a backup motion control unit, provides an increased likelihood of unmanned aerial vehicle retention on the unit to cinematically predetermined path within the allowable error is damaged aerodynamic steering controls. This allows us to conclude that the technical solution meets the criterion of "inventive step".

 The invention is illustrated by figures.

 In FIG. 1 is a structural diagram of a control channel in one of the stabilization planes for an existing unmanned aerial vehicle movement control system.

 In FIG. 2 presents a structural diagram of a control channel in one of the stabilization planes for the inventive motion control system of an unmanned aerial vehicle.

 The inventive device - a control system for the movement of an unmanned aerial vehicle - contains (in Fig. 2 shows one of the identical construction channels of the motion control) unmanned aerial vehicle 1, amplifier 2, steering gear 3, mechanically connected to the aerodynamic control 4, steering gear 6, mechanically connected to the gas-dynamic control 7, the input of the damage identification unit 8 of the aerodynamic control 4 is mechanically connected to the aerodynamic control 4, and the output of the electric unit 8 it is electrically connected to the input of the autopilot 5. The first input of the logical element And 9 is connected to the output of the amplifier 2, and its second input is connected to the additional output of the autopilot 5, the output of the logic element 9 is connected to the input of the steering gear 6.

 The serial connection of the amplifier 2, the steering gear 3 and the aerodynamic control 4 together with the autopilot 5 form the main motion control system of the unmanned aerial vehicle 1. On the other hand, the serial connection of the amplifier 2, the logic element 9, the steering gear 6 and the gas-dynamic control 7 form in conjunction with the damage identification unit 8 of the aerodynamic control element 4 and autopilot 5, a backup control system for the movement of an unmanned aerial vehicle arata 1.

 The device operates as follows. Suppose that during the flight of an unmanned aerial vehicle the aerodynamic control 4 (steering wheel) fails. Failure is caused, for example, by mechanical damage to the steering wheel, expressed in that part of the steering wheel breaks off.

 The reduction in the area of the rudder leads to a change in its basic aerodynamic characteristic — a partial derivative of the lift coefficient of the aircraft with respect to the angle of deviation of the end rudder [2, p. 176].

где c $\genfrac{}{}{0ex}{}{\text{α}}{\text{y1из.кp}}$ - коэффициент нормальной силы изолированного корпуса;
Kδ₀ - коэффициент интерференции;
n - относительная эффективность органа управления;
S_II -площадь неповрежденного аэродинамического органа управления - консолей рулей;
S - характерная площадь летательного аппарата;

относительная площадь руля;
k_т - коэффициент торможения потока в области задних несущих поверхностей (рулей).

where c $\genfrac{}{}{0ex}{}{\text{α}}{\text{y1iz.kp}}$ - coefficient of normal force of the insulated body;
Kδ ₀ is the interference coefficient;
n is the relative efficiency of the governing body;
S _{II - the} area of the intact aerodynamic control body - steering consoles;
S is the characteristic area of the aircraft;

relative rudder area;
k _t - drag coefficient of the flow in the area of the rear bearing surfaces (rudders).

Then the lift generated by the steering wheel is
(Y ₁ ) _II = c $\genfrac{}{}{0ex}{}{\text{δII}}{\text{y1}}$ • q _II • S _II , (2)
where q _II = k _t • q is the average velocity head in the rudder region.

 A decrease in the area of one of the rudders leads to a corresponding decrease in its normal force and the pitch moment developed by this force. As a result, the longitudinal and transverse balancing of the aircraft are disrupted, which, in turn, leads to an uncontrolled turn of the unmanned aerial vehicle in pitch and roll. It should be borne in mind that a slight reduction in rudder area can save an unmanned aerial vehicle within its areas of longitudinal and lateral stability.

 However, there is such a boundary reduction in the area of the rudder that takes the aircraft beyond its stability areas. Loss of stability in the event of a flight, for example, of an unmanned aerial vehicle at a low altitude above the earth or sea surface, can lead to an impact of the aircraft on it. A blow entails the loss of an aircraft and, as a result, failure to fulfill a task.

 Damage identification unit 8 measures the value of the undamaged area of the aerodynamic steering wheel 4 and transmits it in the form of an electric signal to that input of the autopilot 5, which corresponds to the pitch control channel of the unmanned aerial vehicle.

 Autopilot 5 determines the nature of the failure of the aerodynamic control: open circuit in the control system or damage to the steering wheel. An open circuit is recorded in autopilot 5 with a functioning aerodynamic steering wheel, as evidenced by the signal from the damage identification unit of the aerodynamic control element 8 and the absence of reaction of the aircraft 1 to the steering control signal 4.

 The fact of damage to the aerodynamic control element 4 is recorded by the damage identification unit 8. The autopilot 5 determines whether the resulting damage to the steering wheel 4 unmanned aerial vehicle 1 beyond the boundaries of the areas of longitudinal and lateral stability. In the case of significant damage to the steering wheel 4, the autopilot 5 sends a command to the second input of the AND 9 logic element to connect the signal from the output of the amplifier 2 to the backup block of the motion control system.

 Thus, the inclusion of a backup gas-dynamic unit 7 for controlling the movement of an unmanned aerial vehicle allows you to fend off the reduction in the area of the aerodynamic rudder 4 by applying a certain lateral force of the gas-dynamic rudder 7. Due to this redundancy, the aircraft operates within the stability areas and maintains control properties, which allows you to keep the device at a kinetically set trajectories within the margin of error.

 For the claimed device, the probability of keeping the unmanned aerial vehicle on a kinematically specified flight path with the failure of the aerodynamic control is significantly higher than that of the prototype, which is a significant advantage that can dramatically increase the flight safety of unmanned aerial vehicles and ensure the aircraft fulfills its task.

 In order to evaluate the effectiveness of the invention, a digital simulation of the flight of an unmanned aerial vehicle was carried out by the method of statistical tests. During the flight of the device, damage was made to one or several of the four aerodynamic controls. On average, the intact area of each of the aerodynamic rudders was about 80-90%. After measuring the remaining intact area of the aerodynamic rudders, they were backed up by connecting gas-dynamic bodies. Moreover, the gas-dynamic organs during the further flight of the aircraft were no longer damaged.

 The introduction of the proposed motion control system for an unmanned aerial vehicle made it possible to increase the probability of an aircraft approaching a target from 0.7 to 0.9. If the value of the intact area of each of the aerodynamic wheels is reduced from 0.9 to 0.5, then the effectiveness of the proposed control system will increase even more.

 The inventive device is implemented at the technical proposal level and can find application in both manned and unmanned aerial vehicles, for which failures of steering controls are critical.

Claims (1)

 Aircraft motion control system, each control channel of which in one of the stabilization planes contains an autopilot, the first output of which is connected through an amplifier to the input of the steering gear, while the output of the steering gear is connected to the input of the aerodynamic control element, as well as AND logic element, characterized in that an additional steering gear and a gas-dynamic control element are connected in series to each control channel, as well as a damage identification unit, the input of which connected to the output of the aerodynamic control element, and the output connected to the input of the autopilot, the second output of which and the output of the amplifier are connected to the first and second inputs of the logical element And, the output of the logical element And is connected to the input of the additional steering gear.

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