TIM output PWM control motor
PS: For all chip ports, the maximum withstand voltage is 5V to
turn on the PWM wave, and set a waveform as the output of the PWM wave. 300 is set to 100, the speed will be changed from 111 to 30rpm
PID algorithm
Why is there a PID algorithm?
- The physique of the motor cannot be the same
- The same pwm is added to multiple motors, how to maintain the same speed
- External force, load change problem
- Closed-loop control of motor speed, speed measurement -> error calculation -> pwm adjustment
Disadvantages: There is no clear optimization criterion, and the debugging is basically based on experience.
Proportional (P) control: Strength value
Integral (I) control: Response speed
Differential (D) control: When the target value is reached, the inertia overshoot is suppressed
For example: set the speed to 50 rpm, then use the PID algorithm code as follows:
Dead zone control
Q1 and Q2, or Q3 and Q4 cannot be turned on directly, or they will be burned.
There is a reaction time when the transistor is turned on and off, which causes the motor to not turn over instantaneously.
- If it is judged that the current speed rpm_cur and the incoming demand speed pwm have opposite signs, it means that a reverse rotation is required.
- Turn off the pwm wave first
- Then turn the in1 and in2 pins on the motor drive chip off and then on.
- The pwm wave has no negative value, so a pwm = -pwm operation is required
