Hi,
The acceleration data will be used to calculate the velocity. Then I'll add the EPA roll-down drag coefficients to calculate the total force on the car and eventually the vehicle HP (kW). This will be for both chill and standard modes.
Bob Wilson
ps. Those 'down spikes' are the end of the maximum acceleration runs. I targeted 80 mph as my ending speed because the car sounds an excessive speed alarm at 90 mph. Yes, I could have disabled the speed alarm but earlier GPS measured runs showed 80 mph was adequate to our goals.
I'm using a Gulf Coast Data Concepts, Human Activity Monitor:
Each data file has 16,000 data samples covering about 5 minutes which puts a significant load on the OpenSource spreadsheet. Somewhat arbitrary, I used 500 counts, 500/4096 ~= 12.2% G, to trim the non-acceleration elements reducing the samples to 2,185 which was easily handled by the spreadsheet.
- Standard Range Plus Model 3 (version 19.16.2)
- SOC ~75%, 15 mi (24 km) warm-up
- 3711 (empty weight) + 250 (driver) + 15 (EVSE, patch kit) ~= 3976 lbs (8,747 kg)
- 77F (25C)
- asphalt road surface
- wind 0 mph, 9:09 PM (21:09) CST
The acceleration data will be used to calculate the velocity. Then I'll add the EPA roll-down drag coefficients to calculate the total force on the car and eventually the vehicle HP (kW). This will be for both chill and standard modes.
Bob Wilson
ps. Those 'down spikes' are the end of the maximum acceleration runs. I targeted 80 mph as my ending speed because the car sounds an excessive speed alarm at 90 mph. Yes, I could have disabled the speed alarm but earlier GPS measured runs showed 80 mph was adequate to our goals.
I'm using a Gulf Coast Data Concepts, Human Activity Monitor:
Code:
;Title, http://www.gcdataconcepts.com, X16-MPU-ham, ADXL345, MPU-9250
;Version, 1191, Build date, Nov 15 2016, SN:CCDC3016B4874F1
;Start_time, 2019-06-05, 21:09:12.423
;Temperature, -999.00, deg C, Vbat, 4174, mv
;MPU SR, 200,Hz, Accel sens, 4096,counts/g, Gyro sens, 16,counts/dps, Mag SR, 10,Hz, Mag sens, 1666,counts/mT
;Deadband, 50, counts
;DeadbandTimeout, 0,sec
;Time, Ax, Ay, Az, Gx, Gy, Gz, Mx, My, Mz
0.004486,-170,1156,-4192,5,-54,-1
0.018432,96,1210,-3916,-21,-20,-9,-311,-383,-506
0.038421,-396,1242,-4240,-20,-34,0
0.058410,-370,1302,-4166,-25,-13,-8
0.078399,680,1450,-4722,-17,-10,-7,-304,-371,-506
0.098419,-384,1138,-4572,-18,-18,0
0.118408,-584,1142,-4106,-8,1,-7
0.138397,124,978,-3978,7,15,-8
0.158386,250,1096,-4122,16,1,-5
0.178406,-640,1222,-4154,17,-12,3,-296,-387,-514- Time - seconds from start of data file. Use the header to get the 'real time' clock and date.
- Ax - side to side acceleration
- Ay - front to rear acceleration
- Az - top to bottom, gravity, which we use to scale 1 G
- Gx - rotation about the door axis
- Gy - rotation about the front to rear axis
- Gz - rotation around a vertical axis
- Mx - magnetic field along door axis
- My - magnetic field along front to rear axis
- Mz - magnetic field along the vertical axis
Each data file has 16,000 data samples covering about 5 minutes which puts a significant load on the OpenSource spreadsheet. Somewhat arbitrary, I used 500 counts, 500/4096 ~= 12.2% G, to trim the non-acceleration elements reducing the samples to 2,185 which was easily handled by the spreadsheet.
