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searchwing-flight-124 [2019/12/26 04:03] beckmanf added quotes |
searchwing-flight-124 [2019/12/27 10:06] (current) beckmanf [Results / TODO] added fuselage |
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| The last waypoint was landing. After that waypoint was active, the plane lost altitude and then probably stalled and crashed near the street. | The last waypoint was landing. After that waypoint was active, the plane lost altitude and then probably stalled and crashed near the street. | ||
| - | ==== Analysis Landing ==== | + | ==== Landing Analysis ==== |
| When the current waypoint is set to the last "Land" waypoint at 10:40:11, the target altitude is set to 0m. | When the current waypoint is set to the last "Land" waypoint at 10:40:11, the target altitude is set to 0m. | ||
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| Friedrich Beckmann (25.12.2019) | Friedrich Beckmann (25.12.2019) | ||
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| + | ==== Control Analysis ==== | ||
| + | |||
| + | During turns the aircraft sometimes lost quite some altitude. Looking at the logs there is some instance where the control was critical. | ||
| + | |||
| + | | {{::swfl124-controllerstability-1.png|Roll and Pitch problems in turn}} | | ||
| + | | Fig. 4: Roll and Pitch problems in turn | | ||
| + | |||
| + | Figure 4 shows the roll and pitch problems during a turn. The target roll angle is -40° but the actual roll angle is -90°. The target pitch is +15° and the actual pitch is -40°. This is a critical control situtation. | ||
| + | |||
| + | | {{::swfl124-controllerstability-2.png|Altitude and speed loss in turn}} | | ||
| + | | Fig. 5: Altitude and speed loss in turn | | ||
| + | |||
| + | As a result there is an altitude loss of 12m versus the target altitude of 50m and the speed decreases to 9 m/s in the following recovery phase. | ||
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| + | My guess is that the controller settings of PIDP, PIDR and the NAV controller is too aggressive resulting in controller instability and possible control loss under certain circumstances. I suggest a less aggressive control strategy which may result in path following errors but more stable flight behaviour. We can improve controller settings during extensive flight tests later. | ||
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| ==== Results / TODO ==== | ==== Results / TODO ==== | ||
| + | * The new milled fuselage does not seem to show problems during flight. However, the turn behavior of the aircraft was not ideal. Is this related to the fuselage? Not clear, probably controller / wind related. | ||
| * Every non-standard parameter setting should have an exact explanation why we set this. If you don't know what the parameter exactly means: **DO NOT CHANGE THE PARAMETER** | * Every non-standard parameter setting should have an exact explanation why we set this. If you don't know what the parameter exactly means: **DO NOT CHANGE THE PARAMETER** | ||
| * We should reestablish the non-standard parameter list in the gitlab and wiki | * We should reestablish the non-standard parameter list in the gitlab and wiki | ||