Control method for controlling a yaw angle and a roll angle of a vertical take-off aircraft

Abstract

A control method for controlling a yaw angle γ.sub.z and a roll angle γ.sub.x of a vertical take-off aircraft comprising at least two drive groups arranged in opposite side regions of the aircraft so as to be spaced apart from a fuselage of the aircraft is presented. Each drive group comprises at least one first drive unit. The first drive unit is arranged so as to be spaced apart from the fuselage to pivot about a pivot angle α into a horizontal flight position and a vertical flight position.

Claims

1. A control method for controlling a yaw angle (γ.sub.z) and a roll angle (γ.sub.x) of a vertical take-off aircraft (1), the vertical take-off aircraft (1) comprising a fuselage, two wings arranged on opposite sides of the fuselage, each wing having an upper wing surface and a lower wing surface, and two drive groups (3) arranged in opposite side regions of the aircraft (1) so as to be spaced apart from the fuselage, wherein each drive group (3) comprises a first drive unit (4, 5) and a second drive unit (6, 7), wherein the first drive unit (4, 5) and the second drive unit (6, 7) are each arranged so as to pivot about a pivot angle (α) between a horizontal flight position and a vertical flight position, wherein in the horizontal flight position the first drive units (4,5) are arranged above the upper wing surface and the second drive units (6,7) are arranged below the lower wing surface, wherein in the vertical flight position the first drive units are arranged in front of the wings and the second drive units are arranged behind the wings, the method comprising: adapting power generated by each of the drive units (4, 5, 6, 7) in order to reach a predetermined target yaw angle (w.sub.γ.sub.z) and a predetermined target roll angle (w.sub.γ.sub.x); determining, in a determination step, a first yaw control parameter (g.sub.1) and a second yaw control parameter (g.sub.2) as well as a first roll control parameter (r.sub.1) and a second roll control parameter (r.sub.2), wherein the first yaw control parameter (g.sub.1) and the first roll control parameter (r.sub.1) are vertical control parameters for reaching the target yaw angle (w.sub.γ.sub.z) and the target roll angle (w.sub.γ.sub.x) in the vertical flight position, wherein the second yaw control parameter (g.sub.2) and the second roll control parameter (r.sub.2) are horizontal control parameters for reaching the target yaw angle (w.sub.γ.sub.z) and the target roll angle (w.sub.γ.sub.x) in the horizontal flight position; determining, in a subsequent superimposing step, an actuation parameter for each drive unit (4, 5, 6, 7) by a superimposing rule from the vertical control parameters and the horizontal control parameters based on the pivot angle (α); and setting a power of the drive units (4, 5, 6, 7) taking into account the actuation parameters.

2. The control method according to claim 1, wherein the second yaw control parameter (g.sub.2) is determined based on the first yaw control parameter (g.sub.1) by multiplication by a yaw factor.

3. The control method according to claim 1, wherein the second roll control parameter (r.sub.2) is determined based on the first roll control parameter (r.sub.1) by multiplication by a roll factor.

4. The control method according to claim 1, wherein, in the determination step, an actual yaw angle (y.sub.γ.sub.z) and an actual roll angle (y.sub.γ.sub.x) are determined, and wherein the control parameters are each determined by a control algorithm starting from the target yaw angle (w.sub.γ.sub.z) and the target roll angle (w.sub.γ.sub.x) as well as the actual yaw angle (y.sub.γ.sub.z) and the actual roll angle (y.sub.γ.sub.x).

5. The control method according to claim 4, wherein the first yaw control parameter (g.sub.1) is determined based on the target yaw angle (w.sub.γ.sub.z) and the actual yaw angle (y.sub.γ.sub.z) using a first yaw control algorithm (PD.sub.2).

6. The control method according to claim 5, wherein the second yaw control parameter (g.sub.2) is determined based on the target yaw angle (w.sub.γ.sub.z) and the actual yaw angle (y.sub.γ.sub.z) using a second yaw control algorithm (PD.sub.4).

7. The control method according to claim 4, wherein the first roll control parameter (r.sub.1) is determined based on the target roll angle (w.sub.γ.sub.x) and the actual roll angle (y.sub.γ.sub.x) using a first roll control algorithm (PD.sub.1).

8. The control method according to claim 7, wherein the second roll control parameter (r.sub.2) is determined based on the target roll angle (w.sub.γ.sub.x) and the actual roll angle (y.sub.γ.sub.x) using a second roll control algorithm (PD.sub.3).

9. The control method according to claim 5, wherein the first yaw control parameter (g.sub.1) is determined based on the target yaw angle (w.sub.γ.sub.z) and the actual yaw angle (y.sub.γ.sub.z) using a first yaw control algorithm (PD.sub.2), wherein the second yaw control parameter (g.sub.2) is determined based on the target yaw angle (w.sub.γ.sub.z) and the actual yaw angle (y.sub.γ.sub.z) using a second yaw control algorithm (PD.sub.4), wherein the first roll control parameter (r.sub.1) is determined based on the target roll angle (w.sub.γ.sub.x) and the actual roll angle (y.sub.γ.sub.x) using a first roll control algorithm (PD.sub.1), wherein the second roll control parameter (r.sub.2) is determined based on the target roll angle (w.sub.γ.sub.x) and the actual roll angle (y.sub.γ.sub.x) using a second roll control algorithm (PD.sub.3), and wherein at least one of the first yaw control algorithm (PD.sub.2), the second yaw control algorithm (PD.sub.4), the first roll control algorithm (PD.sub.1), or the second roll control algorithm (PD.sub.3) is a linear controller having a P or PD proportion.

10. The control method according to claim 1, wherein, in the superimposing step, the vertical control parameters and the horizontal control parameters are each multiplied by a drive-unit-specific and pivot-angle-specific evaluation function and the actuation parameters for each drive unit (4, 5, 6, 7) are determined by a linear combination of the vertical control parameters multiplied by the drive-unit-specific and pivot-angle-specific evaluation function and the horizontal control parameters multiplied by the drive-unit-specific and pivot-angle-specific evaluation function.

11. The control method according to claim 10, wherein the evaluation function of the vertical control parameters is the cosine of the pivot angle (α) and wherein the evaluation function of the horizontal control parameters is the sine of the pivot angle (α).

12. The control method according to claim 11, wherein the yaw angle (γ.sub.z) and the roll angle (γ.sub.x) are defined in a clockwise manner about a vertical axis and a longitudinal axis, respectively, of the aircraft (1), wherein, in the superimposing step, a first actuation parameter (AP.sub.1) of a first drive unit (4) arranged to the left of the longitudinal axis in a plan view of the aircraft is calculated according to the following model:
AP.sub.1=cos(α).Math.r.sub.1+cos(α).Math.g.sub.1−sin(α).Math.r.sub.2+sin(α).Math.g.sub.2, wherein, in the superimposing step, a second actuation parameter (AP.sub.2) of a first drive unit (5) arranged to the right of the longitudinal axis in a plan view of the aircraft is calculated according to the following model:
AP.sub.2=−cos(α).Math.r.sub.1−cos(α).Math.g.sub.1+sin(α).Math.r.sub.2−sin(α).Math.g.sub.2, wherein, in the superimposing step, a third actuation parameter (AP.sub.3) of a second drive unit (6) arranged to the left of the longitudinal axis in a plan view of the aircraft is calculated according to the following model:
AP.sub.3=cos(α).Math.r.sub.1−cos(α).Math.g.sub.1+sin(α).Math.r.sub.2+sin(α).Math.g.sub.2, wherein, in the superimposing step, a fourth actuation parameter (AP.sub.4) of a second drive unit (7) arranged to the right of the longitudinal axis in a plan view of the aircraft is calculated according to the following model:
AP.sub.4=−cos(α).Math.r.sub.1+cos(α).Math.g.sub.1−sin(α).Math.r.sub.2−sin(α).Math.g.sub.2.

13. The control method according to claim 12, wherein power actuation values (u.sub.1, u.sub.2, u.sub.3, u.sub.4) of the drive units (4, 5, 6, 7), by which the drive units (4, 5, 6, 7) are actuated, are calculated as follows, taking into account a power requirement variable (F) and a pitch parameter (n), in order to generate a desired power of the drive units (4, 5, 6, 7):
u.sub.1=F−n+AP.sub.1,
u.sub.2=F−n+AP.sub.2,
u.sub.3=F+n+AP.sub.3,
u.sub.4=F+n+AP.sub.4.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The FIGURE schematically shows a vertical take-off aircraft.

DETAILED DESCRIPTION

[0032] The FIGURE schematically shows a vertical take-off aircraft 1. The aircraft 1 comprises two drive groups 3 arranged on opposite wings 2 of the aircraft 1, each drive group 3 comprising a first drive unit 4, 5 and a second drive unit 6, 7. The first drive unit 4, 5 and the second drive unit 6, 7 are each arranged on the wing 2 so as to pivot about a pivot angle α into a horizontal flight position and a vertical flight position. In the FIGURE, the drive units 4, 5, 6, 7 are in the horizontal flight position. The first drive units 4, 5 are arranged on the wings 2 above an upper wing surface 8 and the second drive units 6, 7 are arranged on said wings below a lower wing surface 9. When the drive units 4, 5, 6, 7 are pivoted into the vertical flight position, the first drive units 4, 5 and the second drive units 6, 7 are arranged in front of and behind the wings 2 in the horizontal flight direction. A yaw angle γ.sub.z, a roll angle γ.sub.x and a pitch angle γ.sub.y are defined in a clockwise manner about a vertical axis, a longitudinal axis and a transverse axis, respectively, of the aircraft 1.

[0033] The drive units 4, 5, 6, 7 each comprise rotors. The rotors of the first drive unit 4 and the second drive unit 7 rotate anti-clockwise and the rotors of the first drive unit 5 and the second drive unit 6 rotate clockwise.

[0034] In order to control the yaw angle γ.sub.z and the roll angle γ.sub.x, in a determining step of a control method, first and second yaw and roll control parameters g.sub.1, g.sub.2, r.sub.1, r.sub.2 are first determined starting from a predetermined target yaw angle w.sub.γ.sub.z and a predetermined target roll angle w.sub.γ.sub.x by means of linear controllers PD.sub.1, PD.sub.2, PD.sub.3, and PD.sub.4. Actuation parameters u.sub.1, u.sub.2, u.sub.3, u.sub.4 are then determined for each drive unit 4, 5, 6, 7 in a superimposing step from the roll control parameters g.sub.1, g.sub.2, r.sub.1, r.sub.2. In the FIGURE, the determination of the actuation parameter u.sub.1 for the first drive unit 4 is shown by way of example. The determination takes place on the basis of the above-described formulas 1 to 8.