in un articolo avevo letto le differenti velocità di segnale tra una pwm e un sbus, avevano fatto due calcoli su quanta strada un mezzo ad una determinata velocità ( mi sembra di ricordare 80km/h) faceva in più o in meno. il risultato mi ha lasciato un po a bocca aperta, era superiore al metro...
se trovo il post con i dati lo metto qui...
edit: trovato , la differenza era tra sbus e ppm:
Delay
According to Gurus on RCGroups, CPPM and PWM both have around 60ms-80ms delay, and SBUS only have 10ms-20ms delay.
Actually, the delay with PPM is defined by the signal width, which is 18ms (or 27ms in the new firmware which fixed the 8 channel issue). But because the way Cleanflight deals with PPM signal, a 3 points average (or 4 points previously) is used to calculate the PPM input (to prevent signal frame glitches), this causes more delay (3x18ms or 3x27ms).
50ms improvement might not sound like a lot, but it definitely helps! For example for looptime of 1000, each control loop takes 1ms to complete. By going SBUS your quad can react to your stick command 50 control loops earlier. Less delay in RC input will make your quad much more responsive.
BanniUK commented in my post on Multicopter International, he asked how far can the quad travel in that delay period? Very interesting question!
Lets say if your quad is going at 100Km/hr (about 62 MPH) which is 27.8m/s, in 50ms of delay, your quad can travel 1.39 meters which is about 4.5 feet! Wow
se trovo il post con i dati lo metto qui...
edit: trovato , la differenza era tra sbus e ppm:
Delay
According to Gurus on RCGroups, CPPM and PWM both have around 60ms-80ms delay, and SBUS only have 10ms-20ms delay.
Actually, the delay with PPM is defined by the signal width, which is 18ms (or 27ms in the new firmware which fixed the 8 channel issue). But because the way Cleanflight deals with PPM signal, a 3 points average (or 4 points previously) is used to calculate the PPM input (to prevent signal frame glitches), this causes more delay (3x18ms or 3x27ms).
50ms improvement might not sound like a lot, but it definitely helps! For example for looptime of 1000, each control loop takes 1ms to complete. By going SBUS your quad can react to your stick command 50 control loops earlier. Less delay in RC input will make your quad much more responsive.
BanniUK commented in my post on Multicopter International, he asked how far can the quad travel in that delay period? Very interesting question!
Lets say if your quad is going at 100Km/hr (about 62 MPH) which is 27.8m/s, in 50ms of delay, your quad can travel 1.39 meters which is about 4.5 feet! Wow
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