επειδη βλεπω μια συγχυση με τα 4khz ειναι το πιο απλο πραγμα κατεβαστε το betaflight 2,6,0 και βαλτε εκει που εχω στην εικονα το κοκκινο στα 250 kai 4000 και ετοιμος και θα δειτε την μαγεια να γινεται, απλα συνιστω λιγο πιο κατω το P για να μην ειναι σαν σπαστικο το τετρα .
δουλεει σε naze 32 πολυ ανετα και αν θελετε να το κανετε ελενχο γραψτε στο CLI status kai enter και θα δειτε οτι ο επεξεργαστης δουλευει στο 11% το οποιο ειναι super.
μην τρομαξετε αν το τετρακοπτερο στην πρωτη οθονη δεν δουλευει ειναι νορμαλ απο τη στιγμη που αυτοματα κλεινει το accelerometer.
καλες τουμπες
4Khz
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DeanGDFpvracingGR
- Δημοσιεύσεις: 23
- Εγγραφή: Τετ Δεκ 16, 2015 11:12 pm
4Khz
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- betaflight.png (171.19 KiB) 4660 προβολές
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hok
- Δημοσιεύσεις: 1777
- Εγγραφή: Παρ Αύγ 14, 2015 1:22 am
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Re: 4Khz
https://oscarliang.com/best-looptime-flight-controller/
Adriel Perkins shared this article with us where he explained what FC looptime is and whether faster looptime is really better for you. He also talks about ESC refresh rate which is equally important.
With all the new technologies coming out every day in the FPV multirotor world, it’s really hard to keep up. “Looptime” and “refresh rate” are one of the concepts being discussed a lot in the FPV community, with regards to the FC and ESC.
The Different Looptime in Firmware
Today, the four main flight controller firmware are Betaflight, Cleanflight, Raceflight, and the KISS FC firmware. Each firmware can run at a different looptime.
Some of these firmware can operate from 1khz (1000us looptime) all the way up to 8khz (125us looptime). (There are already talks about running 32KHz in Raceflight)
For example in the latest Betaflight, it’s possible to run 8Khz on it though most people tend to run 4khz (250us looptime). The KISS FC runs 1khz (1000us looptime).
But does faster refresh rate (lower looptime) make a difference? Is faster better on paper or is it actually better in real world?
To understand this we first need to understand what looptime’s are. There are two looptimes every pilot has to know about: 1. the flight controller (FC) looptime, and 2. the electronic speed controllers (ESC) looptime.
The FC looptime is basically the time it takes the FC to complete a PID loop and send the PWM signal out to the ESC’s.
The ESC’s have their own looptime. The ESC looptime is how fast it can pick up the PWM signal. The ESC’s looptime should be lower than the looptime of the FC, so that it can pick up data more quickly than the FC can provide, that gives the ESC time to write them to the motors. If the ESC looptime is much faster, the old values will be written to the motors a number of times before getting new data from the FC.
Most ESC’s now run Oneshot125 which is essentially reading inputs from the FC at a looptime of 125us to 250us. Today’s flight controllers (depending on hardware) can run anywhere between 1000us and 125us looptime to get data, run it through the PID control loop, and send it to the ESC.
Don’t get confused about looptime and refresh rate in this article, they mean the same thing, just in different unit: looptime is measured in us (micro second), and refresh rate is measured in Hz.
1000us = 1khz
500us = 2khz
250us = 4khz
125us = 8khz
Oneshot125, Oneshot42, and MultiShot Relation to FC Looptime
When changing the looptime in the FC you must be aware of the protocol on the ESC as well.
As mentioned, Oneshot125 looptime protocol is between 250us and 125us. Likewise, Oneshot42 is between 84us and 42us and Multishot is between 25us and 5us. Oneshot125 can be run on almost all ESC’s with Blheli installed. Oneshot42 is specific to the KISS ESCs at the moment, and Multishot can only be run well on F39X Silabs ESCs such as the DYS XM20A.
It is preferred if your ESC protocol is slightly faster than the looptime of your FC, however the opposite does not hold true. If your FC is running at a faster looptime than your ESC, then the ESC will get behind in its data and can overload the ESC.
This is why Oneshot125 does not work with 8kHz looptime on the FC, 8kHz can cause the Oneshot125 ESC’s to get behind if the ESCs are picking up the signal at the 250us trailing edge of the PWM signal (see below diagram).
lead-trail-edge-pwm-looptime
Likewise, if the multirotor is at full throttle, there won’t be any gap in the PWM signal between the leading and trailing edges so the throttle would be a straight line which will cause issues with reading and writing the PWM data.
Therefore when running Oneshot125, it’s not recommended to run anything above 3.8khz refresh rate on the FC, in order to create a small gap which allows the ESCs to identify the signal properly. (Invalid signal can cause ESC shut-down)
With ESC’s capable of running Multishot, this isn’t really an issue. This is something to be aware of when selecting your FC looptime/refresh rate.
In Practice
In practice the faster the looptime is, particularly with the ESC looptimes (Oneshot125, Oneshot42, Multishot), the higher state of tune you’re able to have. This makes the quad feel more responsive and more locked in. With FC looptimes, the same can be said. However, it’s only marginally different and can allow for some undesired effects to happen. Though it allows your state of tune to increase it is much harder to be able to notice it, especially if you already have a properly tuned multirotor.
The most important thing to note though is that in practice, the lower looptimes on the FC, control loop tend to have the filters turned off, this allows all additional noise to pass through. Most flight controllers have what is called a low-pass filter (LPF). The LPF allows only low frequencies to pass through, while filtering out high frequencies. The purpose of the filter is to reduce excessive noise caused by vibrations thereby making the desired signal more easily readable. (The downside of the filters is adding delay)
Therefore, with lower looptime your quad can also be “noisier”, and the flight controller isn’t always reading the best data as the noise can interfere with the values going through the PID control loop. The added noise gets worse on less rigid frames. It can make tuning harder, and in extreme cases even cause crashes due to noise overload.
At the end of the day though, what looptime you can/should run boils down to:
your hardware and firmware (frame rigidity, ESC, FC)
which looptime you feel more comfortable flying with (you might have better result with tuning with one than another given your current setup)
With most of the current mini quad frames and software/hardware technology I would say that 1khz or 2khz is the most reliable looptime to use. If you have a high quality, extremely rigid frame then you likely can run any of the frequencies fairly well.
Be aware that flying either 1khz or 8khz isn’t going to make you a worse/better pilot. Only practice and tuning is going to do that. I personally fly the KISS flight controller which runs at 1khz. With the tune I have the quad feels as locked in as I want it to be. That is my personal preference. I’ve also tried 4khz on the Cyclone on a 4 inch quadcopter and found that despite the noise that was generated (though not bad) the quadcopter felt very locked in and fun to fly.
Adriel Perkins shared this article with us where he explained what FC looptime is and whether faster looptime is really better for you. He also talks about ESC refresh rate which is equally important.
With all the new technologies coming out every day in the FPV multirotor world, it’s really hard to keep up. “Looptime” and “refresh rate” are one of the concepts being discussed a lot in the FPV community, with regards to the FC and ESC.
The Different Looptime in Firmware
Today, the four main flight controller firmware are Betaflight, Cleanflight, Raceflight, and the KISS FC firmware. Each firmware can run at a different looptime.
Some of these firmware can operate from 1khz (1000us looptime) all the way up to 8khz (125us looptime). (There are already talks about running 32KHz in Raceflight)
For example in the latest Betaflight, it’s possible to run 8Khz on it though most people tend to run 4khz (250us looptime). The KISS FC runs 1khz (1000us looptime).
But does faster refresh rate (lower looptime) make a difference? Is faster better on paper or is it actually better in real world?
To understand this we first need to understand what looptime’s are. There are two looptimes every pilot has to know about: 1. the flight controller (FC) looptime, and 2. the electronic speed controllers (ESC) looptime.
The FC looptime is basically the time it takes the FC to complete a PID loop and send the PWM signal out to the ESC’s.
The ESC’s have their own looptime. The ESC looptime is how fast it can pick up the PWM signal. The ESC’s looptime should be lower than the looptime of the FC, so that it can pick up data more quickly than the FC can provide, that gives the ESC time to write them to the motors. If the ESC looptime is much faster, the old values will be written to the motors a number of times before getting new data from the FC.
Most ESC’s now run Oneshot125 which is essentially reading inputs from the FC at a looptime of 125us to 250us. Today’s flight controllers (depending on hardware) can run anywhere between 1000us and 125us looptime to get data, run it through the PID control loop, and send it to the ESC.
Don’t get confused about looptime and refresh rate in this article, they mean the same thing, just in different unit: looptime is measured in us (micro second), and refresh rate is measured in Hz.
1000us = 1khz
500us = 2khz
250us = 4khz
125us = 8khz
Oneshot125, Oneshot42, and MultiShot Relation to FC Looptime
When changing the looptime in the FC you must be aware of the protocol on the ESC as well.
As mentioned, Oneshot125 looptime protocol is between 250us and 125us. Likewise, Oneshot42 is between 84us and 42us and Multishot is between 25us and 5us. Oneshot125 can be run on almost all ESC’s with Blheli installed. Oneshot42 is specific to the KISS ESCs at the moment, and Multishot can only be run well on F39X Silabs ESCs such as the DYS XM20A.
It is preferred if your ESC protocol is slightly faster than the looptime of your FC, however the opposite does not hold true. If your FC is running at a faster looptime than your ESC, then the ESC will get behind in its data and can overload the ESC.
This is why Oneshot125 does not work with 8kHz looptime on the FC, 8kHz can cause the Oneshot125 ESC’s to get behind if the ESCs are picking up the signal at the 250us trailing edge of the PWM signal (see below diagram).
lead-trail-edge-pwm-looptime
Likewise, if the multirotor is at full throttle, there won’t be any gap in the PWM signal between the leading and trailing edges so the throttle would be a straight line which will cause issues with reading and writing the PWM data.
Therefore when running Oneshot125, it’s not recommended to run anything above 3.8khz refresh rate on the FC, in order to create a small gap which allows the ESCs to identify the signal properly. (Invalid signal can cause ESC shut-down)
With ESC’s capable of running Multishot, this isn’t really an issue. This is something to be aware of when selecting your FC looptime/refresh rate.
In Practice
In practice the faster the looptime is, particularly with the ESC looptimes (Oneshot125, Oneshot42, Multishot), the higher state of tune you’re able to have. This makes the quad feel more responsive and more locked in. With FC looptimes, the same can be said. However, it’s only marginally different and can allow for some undesired effects to happen. Though it allows your state of tune to increase it is much harder to be able to notice it, especially if you already have a properly tuned multirotor.
The most important thing to note though is that in practice, the lower looptimes on the FC, control loop tend to have the filters turned off, this allows all additional noise to pass through. Most flight controllers have what is called a low-pass filter (LPF). The LPF allows only low frequencies to pass through, while filtering out high frequencies. The purpose of the filter is to reduce excessive noise caused by vibrations thereby making the desired signal more easily readable. (The downside of the filters is adding delay)
Therefore, with lower looptime your quad can also be “noisier”, and the flight controller isn’t always reading the best data as the noise can interfere with the values going through the PID control loop. The added noise gets worse on less rigid frames. It can make tuning harder, and in extreme cases even cause crashes due to noise overload.
At the end of the day though, what looptime you can/should run boils down to:
your hardware and firmware (frame rigidity, ESC, FC)
which looptime you feel more comfortable flying with (you might have better result with tuning with one than another given your current setup)
With most of the current mini quad frames and software/hardware technology I would say that 1khz or 2khz is the most reliable looptime to use. If you have a high quality, extremely rigid frame then you likely can run any of the frequencies fairly well.
Be aware that flying either 1khz or 8khz isn’t going to make you a worse/better pilot. Only practice and tuning is going to do that. I personally fly the KISS flight controller which runs at 1khz. With the tune I have the quad feels as locked in as I want it to be. That is my personal preference. I’ve also tried 4khz on the Cyclone on a 4 inch quadcopter and found that despite the noise that was generated (though not bad) the quadcopter felt very locked in and fun to fly.
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hokdog
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