PID tuning profile
P = The present (proportional)
I = The Past (integral)
D = The Future (derivative / damping) !Dangerous
P : Proportional
The P-term controls how accurately the aircraft tracks your inputs (Often referred to as locked-in). Higher values result in better tracking, but can cause an overshoot if the P is too high compared to the D term. P term is like a spring.
The P term determines the strength of the correction the flight controller will input to follow the given directions. A locked-in feeling comes from a higher P term. Higher P higher stiffness, lower P, softer control.
On the other hand, a too high P-term can induce vibrations and oscillations, when the aircraft tries to over-correct.
I : Integral
The I term determines how the aircraft holds the drones positioning in space against external forces. This setting will be seen easily in how your aircraft reacts in free fall. It is like a stiffness slider. If you notice your drone moving in flight when you don’t give any input, make The I term higher.
A too high I term will make your aircraft feel like it’s heavy and unresponsive (too much constraints). In extreme cases, a high I term can cause oscillations. When your I term is too low, your aircraft will feel like it’s sliding and slipping.
When using high I gain, use anti-gravity, it allows the high I term to only be active under throttle punches, and lower when cruising.
D : Derivative (Dangerous)
The D term is the dampening in any direction applied to the equation. It attenuates the effect of prop wash, wind or bounces. More D term helps dampen and reduce over corrections caused by P term and Feed Forward.
Do not use D term to tune out noise, High frequency noise can cause motors to heat up and burn out. D term is very sensitive to gyro noise and that should be tuned out with filters before increasing D term. The D term is like a shock absorber for your aircraft, but magnifies high frequency gyro noise.
A too low D term will induce bounces in movements, making fast movements, prop wash and free falling to be less predictable and induce vibration in the footage and fpv feed. An excessive D term will also cause the aircraft to feel mushy.
A low pass filter is absolutely necessary on the D term to remove high frequency noise.
D min
D min is the minimum value for the derivative, which allows the aircraft to fly at a lower D term when relaxed and the set D term when flying acro.
Feed Forward
Feed forward is a variable that enables sharper response (As P term does) depending on the speed of your sticks. Faster the sticks move, the more feed forward you get. This makes your aircraft more responsive in high speed maneuvers. The advantage of feed forward is that it doesn’t induce oscillations like a high P term does. A high Feed Forward rate can induce overshoots in quick movements. You can also utilize ff_boost to help the motor spin up speed, and make the effects of feed forward smoother.
PID tuning
Here’s the summary of what PID tuning is :
Raise P till quad is "sharp"
Raise D till it's soft enough
Raise I till control becomes loose (slow response)
if oscillation is fast, reduce D
if oscillation is slow, raise D (or lower P)
Sliders
The new betaflight configurator also makes tuning easier by incorporating sliders in the PID tab. They have a brief explanation along with the value. This is based on the stock betaflight PIDs.
In summary, PID tuning is a crucial aspect of drone flight performance that significantly influences how well an aircraft responds to pilot inputs and external conditions. The three components of PID—Proportional (P), Integral (I), and Derivative (D)—each play distinct roles in stabilizing flight:
P (Proportional): Determines the accuracy of control inputs. A higher P-value enhances responsiveness but may lead to oscillations if set too high.
I (Integral): Maintains the drone's position against external forces. While a higher I-value improves stability, it can result in sluggishness if overly increased.
D (Derivative): Functions as a dampening mechanism to prevent overcorrection from the P term. However, excessive D can lead to unresponsive handling and potential damage from high-frequency noise.
Understanding and fine-tuning these parameters is essential for achieving optimal flight characteristics. By carefully adjusting the PID settings, pilots can create a more stable and responsive flying experience, ultimately enhancing both performance and enjoyment in the drone flying hobby.