CN105259903A - Method for designing aircraft automatic flight control system rolling attitude control structure based on signal flow graphs - Google Patents

Abstract

The invention discloses a method for designing an aircraft automatic flight control system rolling attitude control structure based on signal flow graphs. The method comprises the steps of firstly approximately separating local signal flow graphs of a Dutch roll motion mode and a rolling motion mode from a general signal flow graph of aircraft lateral motions; secondly, selecting a forward channel with the minimum number of integrators to act as a control transmission channel of each mode, and determining an optimal feedback loop so as to improve damping and natural frequency characteristics; and finally, configuring the determined feedback control loop to the general signal flow graph of the lateral motions, and determining a lateral rolling attitude control structure. The method disclosed by the invention overcomes a defect that an automatic flight control system rolling attitude optimal control structure cannot be determined because a feedback control loop is selected according to design experience in the prior art.

Description

Aircraft based on signal flow diagram automatic flight control system roll attitude control structure method for designing

Technical field

The present invention relates to flight control system design, particularly a kind of aircraft based on signal flow diagram automatic flight control system roll attitude control structure method for designing.

Background technology

The control of aircraft automatic flight control system roll attitude is the interior control loop of aircraft sideway movement, and is the basic controller of side direction flight tracking control.Roll attitude controls should be able to effectively improve inherent damping characteristic, particularly improves the damping characteristic of Dutch roll motion, stablizes helical motion, and improves inherent characteristic by Handling Quality Requirements, and creates conditions for outer control loop; Reduce the impact that disturbing influence mainly reduces fitful wind; Stabilized flight attitude, or control the roll angle as flight track control variable; Suppress the sideslip etc. in curved flight.The purpose of design of roll attitude controller mainly alleviates the burden of driver, simplifies outer control loop, improves system linearity characteristic, and reduce system " effective order ".

The engineering primary design of aircraft automatic flight control system controller, in full flight envelope, normally choose some working points linearization and decoupling zero process are carried out to aircraft Nonlinear Equations of Motion, and then choose feedback control loop according to design experiences, determine the basic structure of controller.But airplane motion exists a large amount of spendable state variable and manipulated variable, be only difficult to select best controller general structure by design experiences.Such as, in calm situation, have 12 observable state variables and output variable in sideway movement, and at least possess yaw rudder and aileron two manipulated variables, this just may have 24 backfeed loops.If all mix wave filter to these loops, so, design about 48 even more controling parameters, from engineering viewpoint, this is actual is impossible.In addition, such full-state feedback structure can make the reliability of controller greatly reduce.Therefore, degree backfeed loop number being restricted to absolute demand should be managed.

Signal flow diagram describes the relation between Model in Time Domain (i.e. state equation) and frequency-domain model (i.e. transport function), is convenient to carry out flight characteristics analysis and determine controller architecture.Signal flow diagram illustrates the physical process of airplane motion in a diagram form vividerly.First, available signal flow graph discusses inherent characteristic and transmission characteristic, namely studies separate equation parameter to the impact of stability, maneuverability and ornamental.Secondly, the possibility of further reduced equation should be pointed out with signal flow diagram.Finally, the available method similar to signal flow diagram " inner feedback loop " estimates the effect of external feedback, thus designs better controller architecture.

In the prior art, although made many restrictions hypothesis and through linearization process, airplane motion equation is still quite complicated.For controller primary design, assessment determines that rational controller architecture is most important.So, by process flow diagram approximation method, reduced equation group and transport function are highly significant further again, physical relation can be understood better like this, reduce the complex nature of the problem and calculate and consume, be divided into Partial controll task (single control loop) the drawn game portion index of quality, CONTROLLER DESIGN by easy stages.

Some special boundary condition (handling the limit, elastic free degree, reliability etc.) on aircraft do not allow to use high ride gain, if the gain of the transmission channel of corresponding objects is higher, then the gain of controller just may be less, because the product of both, namely the effect of loop gain to controller has decisive influence.In addition, the delay comprised in target transfer function is less, controls simpler.Therefore, in order to implement effective control, should select in whole working range that steady-state gain is large, as far as possible without the transmission channels of delayed response, both can directly be determined by signal flow diagram.

Summary of the invention

For solving the problem, the invention provides a kind of aircraft based on signal flow diagram automatic flight control system roll attitude control structure method for designing.

For achieving the above object, the technical scheme that the present invention takes is:

Aircraft based on a signal flow diagram automatic flight control system roll attitude control structure method for designing, comprises the steps:

S1, respectively choose r, β, p, φ be aircraft side to movement-state, ζ, ξ be aircraft side to motion control amount, each quantity of state configures an integrator, according to aircraft side to motion state equation

Determine the differential expressions of r, β, p, φ quantity of state, i.e. each integrator input signal, form the overall signal flow graph of aircraft sideway movement;

In formula, be respectively yaw rate, yaw angle, angular velocity in roll and the roll angle derivative to the time, N _r, N _β, N _pbe respectively the derivative of yawing to yaw rate, yaw angle and angular velocity in roll, L _r, L _β, L _pbe respectively the derivative of rolling moment to yaw rate, yaw angle and angular velocity in roll, Y _βfor side force is to the derivative of yaw angle, g is acceleration of gravity, V ₀for air speed, ξ, ζ are respectively aileron movement angle and control surface steering angle, N _ξ, N _ζbe respectively the derivative of yawing to aileron movement angle and control surface steering angle, Y _ξ, Y _ζbe respectively the derivative of side force to aileron movement angle and control surface steering angle, L _ξ, L _ζbe respectively the derivative of rolling moment to aileron movement angle and control surface steering angle;

S2, with r, β for quantity of state, ζ is input quantity, selects that the transmission channel of late effect in total signal flow diagram minimum (integrator is minimum) is approximate isolates aircraft sideway movement typical case Dutch roll mode signal flow diagram, and its state equation form is

$\left[\begin{array}{c}\stackrel{\·}{r}\\ \mathrm{\β}\end{array}\right]=\left[\begin{array}{cc}{N}_r& N_{\mathrm{\β}}\\ -1& Y_{\mathrm{\β}}\end{array}\right]\left[\begin{array}{c}r\\ \mathrm{\β}\end{array}\right]+\left[\begin{array}{c}{N}_{\mathrm{\ξ}}\\ 0\end{array}\right]\mathrm{\ξ};$

S3, from Dutch roll mode signal flow diagram, select uniquely can to improve the feedback control loop N of yaw rate to control surface steering angle of Dutch roll mode damping characteristic _r, selection uniquely can improve the feedback control loop N of yaw angle to control surface steering angle of Dutch roll mode characteristic frequency _β;

S4, be respectively quantity of state and input quantity with p, φ and ξ, select the transmission channel of late effect minimum (integrator is minimum) in total signal flow diagram to be similar to and isolate aircraft sideway movement typical case rolling movement mode signals flow graph, its state equation form is

$\left[\begin{array}{c}\stackrel{\·}{p}\\ \mathrm{\φ}\end{array}\right]=\left[\begin{array}{cc}Lp& 0\\ 1& 0\end{array}\right]\left[\begin{array}{c}p\\ \mathrm{\φ}\end{array}\right]+\left[\begin{array}{c}L\mathrm{\ξ}\\ 0\end{array}\right]\mathrm{\ξ};$

S5, from rolling movement mode signals flow graph, select uniquely can to improve the feedback control loop L of angular velocity in roll to aileron movement angle of rolling movement modal damping characteristic _p, selection uniquely can improve the feedback control loop L of roll angle to aileron movement angle of spiral mode stability _φ;

S6, be configured at original system by being similar to the feedback control loop that Dutch roll mode and rolling mode selects according to side direction simultaneously, and make yaw angle instruction be always 0, to reduce the coupling of Dutch roll mode and rolling movement mode; Make the input that roll angle instruction controls as automatic flight control system inner looping.

The present invention has following beneficial effect:

By equations turned to motion linearization for aircraft side be the obvious signal flow diagram of physical significance, be similar to from resultant signal flow graph and isolate Dutch roll mode of motion and rolling movement mode, and then the passage selecting integrator minimum is each Model control passage, and determine that feedback control amount is to configure corresponding backfeed loop, thus determine the general structure of side direction roll attitude controller, overcome in prior art and choose according to design experiences the deficiency that feedback control loop causes determining automatic flight control system roll attitude Optimal Control structure.

Accompanying drawing explanation

The signal flow diagram of Typical Aircraft sideway movement kinetic linearity state equation in Fig. 1 embodiment of the present invention;

Aircraft sideway movement typical case's Dutch roll mode and rolling mode approximate signal signal flow diagram in Fig. 2 embodiment of the present invention;

In Fig. 3 embodiment of the present invention, aircraft sideway movement typical case roll attitude controls general structure signal flow diagram.

Embodiment

In order to make objects and advantages of the present invention clearly understand, below in conjunction with embodiment, the present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, be not intended to limit the present invention.

Embodiments provide a kind of aircraft based on signal flow diagram automatic flight control system roll attitude control structure method for designing, comprise the steps:

S1, respectively choose r, β, p, φ be aircraft side to movement-state, ζ, ξ be aircraft side to motion control amount, each quantity of state configures an integrator, according to aircraft side to motion state equation

Determine the differential expressions of r, β, p, φ quantity of state, i.e. each integrator input signal, form the overall signal flow graph (as shown in Figure 1) of aircraft sideway movement;

In formula, be respectively yaw rate, yaw angle, angular velocity in roll and the roll angle derivative to the time, N _r, N _β, N _pbe respectively the derivative of yawing to yaw rate, yaw angle and angular velocity in roll, L _r, L _β, L _pbe respectively the derivative of rolling moment to yaw rate, yaw angle and angular velocity in roll, Y _βfor side force is to the derivative of yaw angle, g is acceleration of gravity, V ₀for air speed, ξ, ζ are respectively aileron movement angle and control surface steering angle, N _ξ, N _ζbe respectively the derivative of yawing to aileron movement angle and control surface steering angle, Y _ξ, Y _ζbe respectively the derivative of side force to aileron movement angle and control surface steering angle, L _ξ, L _ζbe respectively the derivative of rolling moment to aileron movement angle and control surface steering angle;

S2, with r, β for quantity of state, ζ is input quantity, select the transmission channel of late effect minimum (integrator is minimum) in total signal flow diagram to be similar to and isolate aircraft sideway movement typical case's Dutch roll mode signal flow diagram (as shown in Figure 2), its state equation form is

$\left[\begin{array}{c}\stackrel{\·}{r}\\ \mathrm{\β}\end{array}\right]=\left[\begin{array}{cc}{N}_r& N_{\mathrm{\β}}\\ -1& Y_{\mathrm{\β}}\end{array}\right]\left[\begin{array}{c}r\\ \mathrm{\β}\end{array}\right]+\left[\begin{array}{c}{N}_{\mathrm{\ξ}}\\ 0\end{array}\right]\mathrm{\ξ};$

S3, from Dutch roll mode signal flow diagram, select uniquely can to improve the feedback control loop N of yaw rate to control surface steering angle of Dutch roll mode damping characteristic _r, selection uniquely can improve the feedback control loop N of yaw angle to control surface steering angle of Dutch roll mode characteristic frequency _β;

S4, be respectively quantity of state and input quantity with p, φ and ξ, select the transmission channel of late effect minimum (integrator is minimum) in total signal flow diagram to be similar to and isolate aircraft sideway movement typical case's rolling movement mode signals flow graph (as shown in Figure 2), its state equation form is

$\left[\begin{array}{c}\stackrel{\·}{p}\\ \mathrm{\φ}\end{array}\right]=\left[\begin{array}{cc}Lp& 0\\ 1& 0\end{array}\right]\left[\begin{array}{c}p\\ \mathrm{\φ}\end{array}\right]+\left[\begin{array}{c}L\mathrm{\ξ}\\ 0\end{array}\right]\mathrm{\ξ};$

S5, from rolling movement mode signals flow graph, select uniquely can to improve the feedback control loop L of angular velocity in roll to aileron movement angle of rolling movement modal damping characteristic _p, selection uniquely can improve the feedback control loop L of roll angle to aileron movement angle of spiral mode stability _φ;

S6, be configured at original system by being similar to the feedback control loop that Dutch roll mode and rolling mode selects according to side direction simultaneously, and make yaw angle instruction be always 0, to reduce the coupling of Dutch roll mode and rolling movement mode; Make the input that roll angle instruction controls as automatic flight control system inner looping.

This concrete enforcement is according to the correlativity of the quantity of state of sideway movement and lateral movement characteristics, be divided into Dutch roll mode of motion (quantity of state r, β and signal transmission passage thereof) and rolling movement mode (quantity of state p, φ and signal transmission passage thereof) two parts by approximate for aircraft sideway movement overall signal flow graph, the reduced form of its state equation is respectively:

$\left[\begin{array}{c}\stackrel{\·}{r}\\ \mathrm{\β}\end{array}\right]=\left[\begin{array}{cc}{N}_r& N_{\mathrm{\β}}\\ -1& Y_{\mathrm{\β}}\end{array}\right]\left[\begin{array}{c}r\\ \mathrm{\β}\end{array}\right]+\left[\begin{array}{c}{N}_{\mathrm{\ξ}}\\ 0\end{array}\right]\mathrm{\ξ}$

$\left[\begin{array}{c}\stackrel{\·}{p}\\ \mathrm{\φ}\end{array}\right]=\left[\begin{array}{cc}Lp& 0\\ 1& 0\end{array}\right]\left[\begin{array}{c}p\\ \mathrm{\φ}\end{array}\right]+\left[\begin{array}{c}L\mathrm{\ξ}\\ 0\end{array}\right]\mathrm{\ξ}$

For Dutch roll mode of motion and rolling movement mode two parts approximate signal flow graph, be all the control channel of respective mode from controlled quentity controlled variable to the transmission channel of quantity of state integrator minimum number (late effect is minimum) in selection signal flow diagram, thus the single input realizing each mode control.

In Dutch roll mode of motion and rolling movement mode signals transmission channel, all have and only have unique angular velocity quantity of state (r and p) can in order to improve the damping characteristic of respective mode.Therefore, can determine that yaw rate r to control surface steering angle ζ, angular velocity in roll p are to aileron movement angle ξ two feedback control loops, to improve each modal damping characteristic.

After determining that yaw rate r to control surface steering angle ζ feedback control loop improves feedback control loop as damping, in Dutch roll mode of motion signal transmission passage, only surplus quantity of state β can be used for improving Dutch roll mode of motion frequency characteristic.Thus, determine yaw angle β to control surface steering angle ζ feedback control loop, to improve Dutch roll mode of motion frequency characteristic.

After determining that angular velocity in roll p improves feedback control loop to aileron movement angle ξ feedback control loop as damping, in rolling movement mode signals transmission channel, only surplus quantity of state φ can be used for realizing the control of side direction roll attitude, and stablizes helical motion.Thus, determine that roll angle φ is to aileron movement angle ξ feedback control loop, control to realize side direction roll attitude, and stablize helical motion.

If yaw angle is always β=0, from signal flow diagram, Dutch roll mode is to the coupling L of rolling movement mode _βto eliminate completely, thus, determine that yaw angle instruction is always 0.

The feedback control loop determined more than comprehensive and yaw angle instruction, can determine aircraft automatic flight control system side direction roll attitude controller general structure completely.

The above is only the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, under the premise without departing from the principles of the invention; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.

Claims (1)

1., based on an aircraft automatic flight control system roll attitude control structure method for designing for signal flow diagram, it is characterized in that, comprise the steps:

S1, respectively choose r, β, p, φ be aircraft side to movement-state, ζ, ξ be aircraft side to motion control amount, each quantity of state configures an integrator, according to aircraft side to motion state equation

Determine the differential expressions of r, β, p, φ quantity of state, i.e. each integrator input signal, form the overall signal flow graph of aircraft sideway movement;

In formula, be respectively yaw rate, yaw angle, angular velocity in roll and the roll angle derivative to the time, N _r, N _β, N _pbe respectively the derivative of yawing to yaw rate, yaw angle and angular velocity in roll, L _r, L _β, L _pbe respectively the derivative of rolling moment to yaw rate, yaw angle and angular velocity in roll, Y _βfor side force is to the derivative of yaw angle, g is acceleration of gravity, V ₀for air speed, ξ, ζ are respectively aileron movement angle and control surface steering angle, N _ξ, N _ζbe respectively the derivative of yawing to aileron movement angle and control surface steering angle, Y _ξ, Y _ζbe respectively the derivative of side force to aileron movement angle and control surface steering angle, L _ξ, L _ζbe respectively the derivative of rolling moment to aileron movement angle and control surface steering angle;

S2, with r, β for quantity of state, ζ is input quantity, selects that the transmission channel of late effect in total signal flow diagram minimum (integrator is minimum) is approximate isolates aircraft sideway movement typical case Dutch roll mode signal flow diagram, and its state equation form is

S3, from Dutch roll mode signal flow diagram, select uniquely can to improve the feedback control loop N of yaw rate to control surface steering angle of Dutch roll mode damping characteristic _r, selection uniquely can improve the feedback control loop N of yaw angle to control surface steering angle of Dutch roll mode characteristic frequency _β;

S4, be respectively quantity of state and input quantity with p, φ and ξ, select the transmission channel of late effect minimum (integrator is minimum) in total signal flow diagram to be similar to and isolate aircraft sideway movement typical case rolling movement mode signals flow graph, its state equation form is

S5, from rolling movement mode signals flow graph, select uniquely can to improve the feedback control loop L of angular velocity in roll to aileron movement angle of rolling movement modal damping characteristic _p, selection uniquely can improve the feedback control loop L of roll angle to aileron movement angle of spiral mode stability _φ;

S6, be configured at original system by being similar to the feedback control loop that Dutch roll mode and rolling mode selects according to side direction simultaneously, and make yaw angle instruction be always 0, to reduce the coupling of Dutch roll mode and rolling movement mode; Make the input that roll angle instruction controls as automatic flight control system inner looping.