casainho said:
So I see (sumtorque/PAS) as an average or integral. If user pedals 1 impulse per second -> PAS = 1; max of torque pulse / 1 = max of torque pulse. If pedals 2 pulses per second, PAS = 2; (max of torque pulse * 2) / 2 = max of torque pulse -- assuming max of torque pulse equal in the 2 pulses.
I think I have to explain this in detail.
You get several PAS Pulses with one crank revolution. How many pulses you get depends on your system. With a normal PAS disk from the common corversion kits you can easily count the number of magnets that are placed in the disk (normally something about 8 till 12 magnets). With the various Torque-Sensors, there are much more PAS pulses e.g. 16 or even 32 pulses per crank revolution.
In my code the number of PAS-Pulses per crank revoltion is defined in the main.h
Code:
#define NUMBER_OF_PAS_MAGS 16 //16 for sensor from BMSBattery, 32 for Sempu-Sensor
With each PAS-pulse detected (by the PAS-Pin Interrupt), the torque at the crank is read in (in a single AD-conversion) and stored into an array that has the length of "NUMBER_OF_PAS_MAGS"
Code:
...
ui8_temp = adc_read_throttle (); //read in recent torque value
...
ui16_torque[ui8_torque_index]= (uint8_t) map (ui8_temp , ADC_THROTTLE_MIN_VALUE, ADC_THROTTLE_MAX_VALUE, 0, SETPOINT_MAX_VALUE);
then all values in the array are added to get the value sumtorque, that stands for the average torque at the crank within one crank revolution.
Code:
ui16_sum_torque = 0;
for(a = 0; a < NUMBER_OF_PAS_MAGS; a++) { // sum up array content
ui16_sum_torque+= ui16_torque[a];
}
The value "PAS" is the duration between two PAS-Pulses. The faster you turn the crank, the lower PAS gets. So the cadence is proportional to 1/PAS.
The "PAScounter" is incremented each fast loop run (15,625 kHz). With each PAS interrupt the PAS value is set to the PASCounter value und the PAS Counter gets resetted.
Code:
if (ui8_PAS_Flag == 1) //ui8_PAS_Flag is set by the PAS-Pin interrupt routine
{
ui16_PAS=ui16_PAS_Counter; //save recent cadence
ui16_PAS_Counter=0; //reset PAS Counter
ui8_PAS_Flag =0; //reset interrupt flag
So you have the information for an average torque at the crank and the information of the duration between two PAS-Pulses and you can calculate the already known function
Code:
ui32_setpoint=(fummelfaktor*sumtorque)/PAS; //calculate setpoint
as you can read from the word "
fummelfaktor" this factor is not physically derived but set by trial and error, yet :wink: .
. (Do not ever, I mean never-ever, use Germany company Hermes for getting anything shipped. Ever.)
