Thanks everyone for your replies. I’ve learned a lot of useful knowledge and practical experience here.
Following the AMC procedures, I tested the motor thrust using a thrust test bench. I input throttle, PWM, voltage, current and thrust data into the spreadsheet in the corrected version of AMC, but the corrected thrust curve failed to generate.
I then imported the same data into the original ArduPilot Wiki Spreadsheet, which successfully generated both the real test thrust and corrected thrust curves. However, I had to set MOT_THST_EXPO = 0.01 to get the corrected thrust to fit my measured thrust data.
According to the official Wiki, the recommended MOT_THST_EXPO value is 0.66 for hobby-grade multicopters with 15-inch propellers.
This makes me wonder if my ESC already provides excellent linear compensation by design, which allows MOT_THST_EXPO = 0.01 to match the measured thrust curve perfectly — or if I made a mistake during the testing and configuration process.
Additionally, I noticed a work-in-progress tool called Thrust Expo in the ArduPilot Web Tool. After entering my throttle percentage, PWM, voltage, current and thrust readings into this tool, I got the same result:
with MOT_THST_EXPO = 0.01, the red reference curve aligns almost perfectly with the blue measured thrust curve.
I would like to ask for your advice:
Does this mean my ESC and motor combination has exceptionally linear thrust response? Or is there an error in my test method?
From what I know, 0.01 is an extremely low and unusual setting for thrust exponent. For T-MOTOR Flame series ESCs, the official recommended MOT_THST_EXPO value is 0.25.
My thrust test bench operates with a PWM range from 1000 to 2000. It only allows a minimum throttle increment of 1%, with the throttle adjustable and recorded once per second.
I set the test to ramp the PWM from 1000 to 2000, increasing the throttle by 1% every second and logging the thrust value at the same interval. As a result, the curve is generated from only 100 data points in total. I’m not sure if this resolution is sufficient and adequate enough.