krassi-simeonov / stm32_simplefoc_inlinecurrentsense

Port of the SimpleFOC code to STM32 environment. (Original code here: https://github.com/simplefoc/Arduino-FOC/tree/v2.1)

STM32_SimpleFOC_InlineCurrentSense

[UPDATE 30/06/21]: Added support for AS5048A position sensor.

Port of the SimpleFOC code to STM32 environment. (Original code here: https://github.com/simplefoc/Arduino-FOC/tree/v2.1)

Current hardware used:

• Nucleo-H743ZI2, caution board number is: MB1364, which means the correct user manual is: https://www.st.com/resource/en/user_manual/dm00499160-stm32h7-nucleo144-boards-mb1364-stmicroelectronics.pdf
• SimpleFOCShield v2.0.2
• Motor: low resistance (39mOhm phase resistance) D5065 with 7 pole pairs
• Motor: gimbal iPower GM2804 with AS5048A encoder

SimpleFOCShield is configured with the following connections:

Signal	Arduino pin name	STM32 pin name	Function
PWM A	9 (**broken off, see below)	PE14	TIM1(CH4)
PWM B	5	PE11	TIM1(CH2)
PWM C	6	PE9	TIM1(CH1)
Enable	8	PF3	GPIO_Output
Encoder A	3	PE13	GPIO_EXTI3
Encoder B	2	PG14	GPIO_EXTI14
Encoder Idx	11	PB5	GPIO_EXTI5
Phase A	A0	PA3	ADC1_INP15
Phase B	A2	PC3_c	ADC3_INP1
SCK (CLK to SPI slave)	D13	PA5	SPI1_CLK
MISO	D12	PA6	SPI1_MISO
MOSI	n/a (*** can't use D11)	PA7	SPI1_MOSI
CS (chip select)	D10	PD14	SPI1_CS
Range	(3.3V)	n/a	n/a
Enable 8V regulator	(true)	n/a	n/a

** In order to route the TIM1(CH4) PWM signal which is configure to be output onto pin PE14 of the STM board, pin 9 on the SimpleFOC shield is removed and a jumper lead is used to Arduino pin D4 to Arduino pin D9.

*** On Arduino SPI for MOSI would be D11. In our setup EncoderIdx uses this pin. So we route SPI1 MOSI to PA7 of STM32H743 chip instead. For this to work we need to remove the D11 pin from SimpleFOC shield - in the same way we broke off pin9.

Issues:

• [Resolved] phase current measurement is not accurate, hence cannot use true FOC
  • current limit has to be set ~1-2Amps, and the PID parameters of the Q/D current loops need to be adjusted to accommodate a low-resistance motor. Table included here records working values.

Improvements to be made:

• avoid pulse_counter overflow. Count number of rotations, and keep pulse_counter between 0 - CPR

• switch to dedicated timer hardware for encoder pulse count. Requires hardware signal re-routing

• implement cogging torque measurements in voltage mode

Unresolved questions:

• operating in FOC position control, encoder pulse counter does not increment properly when motor is externally pushed out of position. Hence, motor can be successfully pushed away from target position set point. Would expect this not to happen
• regeneration support
• bandwidth of control loop - probably affects the maximum update position rate

TODO:

• simulate motion of engine under external combustion torques with pre-defined position changes
• update enclosure design to fit onto motor shaft.