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Ki and Kp adjust how quickly the motor current matches what you are inputting via the accelerator. Different values will affect the response and will cause oscillations and a feeling of jerkiness if they don't match the motor and system voltage.
t-pos-gain and t-pwm gain adjust the sensitivity of the accelerator. The equation in the code is:
Throttle = throttle_input * t-pos-gain / 8 - PWM * t-pwm-gain / 8
Because PWM is essentially related to vehicle speed, the default setting of 8 and 0 (for t-pos-gain and t-pwm-gain, respectively) mean that the output current will always be equal to the throttle input. Changing the settings to 16 and 0 would make the throttle twice as sensitive since the code will multiply the throttle input by a factor of 2.
Increasing the value of t-pwm-gain will cause the throttle to decrease as the vehicle speeds up and has the effect of making the throttle less sensitive at higher speeds. This is useful for applications that require high amps at low speed and less sensitive throttle at higher speeds. Settings of 16 and 8 would make the throttle twice as sensitive at low speeds; the throttle will become less sensitive as the vehicle speed (and PWM) increase. If PWM were to go to its max, the throttle would return to normal sensitivity. A setting of 16 and 12 would have a similar effect, but the throttle would be at normal sensitivity at 66% PWM and only half sensitivity at 100% PWM.
c-rr defines how quickly the throttle responds to controller input. Higher values create a more responsive feel while lower values are smoother and more gradual.
The table below includes controller settings for various applications. These are all settings that are changeable via serial cable and terminal software. Use this information to help tune your controller - Once it's working well, add your data to the table!
|N||UserName||Pack Voltage||Motor Brand/Model||Vehicle Weight||Kp||Ki||t-pos-gain||t-pwm-gain||c-rr||Comments|
|1||Joe||144V||Impulse 9||3750 lb||2||20||17||9||6||Very smooth 100% of the time. Throttle settings have a very natural feel|
|2||Adam||36V||GE 6"||1125 lb||300||150||8||0||6||Very smooth 100% of the time. A side note, This is a direct drive golf cart.|
|3||Chris||48V (maybe upgrade to higher in future)||?? (Pulled off Scrapped Fork Truck; tag was unreadable)||?? lb||???||???||?||?||?||Just finished building controller, still collaborating for my EV Motorcycle|
|4||Mike||96V||ADC L91-4003||3000 lb||6||50||17||9||15||Very smooth now: after building my controller I ran on the settings installed by Paul i.e. 2, 160, 0, 0, 6. New setting have removed the lag time at start off to a smoother, linear performance, i.e. 0-40 MPH 12 seconds at new settings. 2,500 miles and counting.|
|5||Greg||144V||Impulse 9||2200 lb||2||11||17||0||6||I started with Joe's settings, but it felt a bit to lively, probably due to my car being much lighter. The weight is an estimate, still need to get it weighed.|