Method for controlling an aircraft, control device for an aircraft and aircraft with such a control device
A method for controlling an aircraft, in particular a VTOL multirotor aircraft, in which flight influencing units of the aircraft a) are supplied with control commands via a first/control channel from a first computer (COM), which control commands originate or are derived from a pilot input (PE), and b) the control commands are monitored by a second/monitoring channel and a second computer (MON), which checks whether the control commands are suitable for a given physical state of the aircraft and the pilot input, c) the second computer determines whether a current navigation state of the aircraft coincides with the pilot input, which has been transformed into a desired navigation state of the aircraft, preferably by the second computer, within a prescribed deviation, and d) a control signal for controlling the aircraft is generated in dependence on a determination result of step c).
1. A method for controlling an aircraft ( 1 ), by which flight influencing units ( 2 . 1 , . . . , 2 .N) of the aircraft ( 1 ) are controlled, the method comprising:
a) supplying the flight influencing units with control commands (SB) via a first channel from a first computer (COM), the control commands (SB) originate from or are derived from a pilot input (PE),
b) monitoring the control commands (SB) by a second channel and a second computer (MON), the second computer (MON) checking whether the control commands (SB) are suitable for a given physical state of the aircraft ( 1 ) and the pilot input (PE),
c) determining by the second computer (MON) whether a current navigation state of the aircraft ( 1 ) coincides with the pilot input (PE), the pilot input (PE) having been transformed into a desired navigation state of the aircraft ( 1 ) within a prescribed deviation, and checking, by a reverse control assignment, whether the control commands (SB) during an activation of the flight influencing units ( 2 . 1 , . . . , 2 .N) of the aircraft ( 1 ) lead to a first force/moment vector τ Cmd for the aircraft ( 1 ) which is suitable for the given physical state of the aircraft ( 1 ), by at least one of:
i) comparing the first force/moment vector, derived from the control commands (SB), with a second force/moment vector τ MON , said second force/moment vector being determined independently of the first force/moment vector,
ii) checking for the first force/moment vector whether at least one of an axis or an amount of a torque contained in the first force/moment vector lies within a prescribed tolerance interval, or
iii) checking for the first force/moment vector whether the first force/moment vector coincides with the pilot input (PE) within the prescribed deviation; and,
d) generating a control signal or an adapted control signal for controlling the aircraft ( 1 ) in dependence on a determination result of the determining in step c) and a checking result of steps i) to iii).
2. The method as claimed in claim 1 , wherein, in step c), at least one of the following navigation state attributes of a navigation state is checked:
a position in flight;
rotational speeds;
change in rates of rotation;
speed with respect to at least one of air or ground;
altitude; or
acceleration.
3. The method as claimed in claim 1 , wherein the first force/moment vector τ Cmd , derived from the control commands (SB), is given by the relationship:
τ
Cmd
=
(
m
_
1
b
m
_
2
b
⋯
m
_
N
b
f
_
1
b
f
_
2
b
⋯
f
_
N
b
)
︸
K
·
(
Ω
1
2
Ω
2
2
⋮
Ω
N
2
)
︸
Ω
with a matrix K, elements m (moment) and f (force) being given by a configuration of the aircraft ( 1 ) and the flight influencing units ( 2 . 1 , . . . , 2 .N), and with a setpoint output value vector Ω with the control commands (SB) of the first computer (COM) for the flight influencing units ( 2 . 1 , . . . , 2 .N).
4. The method as claimed in claim 1 , wherein, in step c) a plurality of checking/comparison methods are respectively used in order to obtain a corresponding plurality of checking/comparison results, said plurality of checking/comparison results are subsequently respectively weighted and then combined with one another in order to obtain at least one of a combined determination result or a combined checking result for use in step d).
5. The method as claimed in claim 4 , wherein each checking/comparison method from the plurality of checking/comparison methods is assigned at least a first weighting factor and at least a second weighting factor, the first weighting factor and the second weighting factor are combined to form an overall weighting factor for said each checking/comparison method, and an associated checking/comparison result is weighted with said overall weighting factor.
6. The method as claimed in claim 5 , wherein the first weighting factor and the second weighting factor for said each checking/comparison method are multiplied by one another.
7. The method as claimed in claim 5 , wherein the first weighting factor is a severity weighting factor, which indicates how severe a fault that is detected by a given checking/comparison method is for the aircraft ( 1 ) or control thereof.
8. The method as claimed in claim 5 , wherein the second weighting factor is a confidence weighting factor, which indicates how accurately a fault that is detected by a given checking/comparison method is quantitatively specified for the aircraft ( 1 ) or control thereof.
9. The method as claimed in claim 4 , wherein a sum is formed from the plurality of weighted checking/comparison results in order to obtain the combined checking result for use in step d).
10. The method as claimed in claim 4 , wherein the plurality of checking/comparison methods are chosen from a group comprising the following methods:
frequency analysis;
Kalman filters;
CBIT and PBIT results;
out-of-range assessments; or
expected values from models.
11. A controller ( 4 ) for an aircraft ( 1 ), the controller comprising:
a first computer (COM) with a first channel, the first computer (COM) is configured for supplying flight influencing units ( 2 . 1 , . . . , 2 .N) of the aircraft ( 1 ) via the first channel with control commands (SB) from the first computer (COM), the control commands (SB) originate from or are derived from a pilot input (PE), and
a second channel and a second computer (MON), the second computer (MON) is configured to monitor the first computer (COM), wherein the second computer (MON) is configured to check whether the control commands (SB) are suitable for a given physical state of the aircraft ( 1 ) and the pilot input (PE),
the second computer (MON) is configured to determine whether a current navigation state of the aircraft ( 1 ) coincides with the pilot input (PE), wherein the pilot input (PE) has been transformed into a desired navigation state of the aircraft ( 1 ) within a prescribed deviation, and the second computer (MON) is also configured to generate and output a control signal for controlling the aircraft ( 1 ) in dependence on a determination result of the determination;
wherein the second computer (MON) is also configured to check by a reverse control assignment whether the control commands (SB) during an activation of the flight influencing units ( 2 . 1 , . . . , 2 .N) of the aircraft ( 1 ) lead to a first force/moment vector which is suitable for the given physical state of the aircraft ( 1 ), in that the second computer (MON) is configured to at least one of:
i) compare the first force/moment vector, derived from the control commands (SB), with a second force/moment vector, said second force/moment vector is determined independently of the first force/moment vector,
ii) check for the first force/moment vector whether an axis and/or an amount of a torque contained in the first force/moment vector lies within a prescribed tolerance interval, or
iii) check for the first force/moment vector whether the first force/moment vector coincides with the pilot input (PE) within the prescribed deviation; and
the second computer (MON) is configured to generate and output an adapted control signal for controlling the aircraft ( 1 ) in dependence on a checking result according to i) to iii).
12. The controller ( 4 ) as claimed in claim 11 , wherein the second computer (MON) is further configured to use a plurality of checking/comparison methods in order to obtain a corresponding plurality of checking/comparison results, said plurality of checking/comparison results are subsequently respectively weighted and then combined with one another in order to generate at least one of a combined determination result or a combined checking result and output to generate at least one of the control signal or the adapted control signal.
13. The controller ( 4 ) as claimed in claim 11 , wherein the controller is configured to check at least one of the following navigation state attributes of a navigation state:
a position in flight;
rotational speeds;
change in rates of rotation;
speed with respect to at least one of air or ground;
altitude; or
acceleration.
14. The aircraft ( 1 ) comprising the flight influencing units ( 2 . 1 , . . . , 2 .N) and the controller ( 4 ) as claimed in claim 11 , said controller ( 4 ) is operatively connected to the flight influencing units ( 2 . 1 , . . . , 2 .N) and configured to send the control commands (SB) to the flight influencing units ( 2 . 1 , . . . , 2 .N).
15. The aircraft of claim 14 , wherein the aircraft is a multirotor aircraft and the flight influencing units are electrically driven drive units.