Contents
What is the resolution of servo motor?
Servo motor resolution is determined by feedback device of motor. I.e. 1000 PPR (pulses per revolution) quadrature encoder yields 1/4000 revolution resolution because 1000 PPR equals 4000 counts per revolution after standard 4X decoding.
Does servo use PWM?
Servos are controlled by sending an electrical pulse of variable width, or pulse width modulation (PWM), through the control wire. There is a minimum pulse, a maximum pulse, and a repetition rate. A servo motor can usually only turn 90° in either direction for a total of 180° movement.
Which encoder is used in servo motor?
The servo amplifier controls the rotation angle of the motor by checking whether it has moved to the target rotation angle. This method of control by using an encoder to detect the motor rotation speed and rotation angle is called feedback control (closed loop).
How to calculate PWM resolution for a servo motor?
Given that FCLK is known as well as FPWM, even PSC is now known. After we’ve found the PSC that maximizes PWM resolution, now plug all variables in the equation and solve for ARR. Last but not least, the servo motor’s minimum & maximum pulse width specs given in the datasheet.
What’s the minimum pulse width for a servo?
That’s a too accurate control signal for such an application and seems more like overkill but let’s continue. Suppose that our servo motor has a minimum pulse width of 0.6ms (for the 0° position) and a maximum pulse of 2.4ms (for the 180° position).
How is the angle of a servo motor determined?
Therefore, the PWM signal’s resolution dictates how fine can we adjust the servo motor’s angle. The range of the angle in degrees is from 0 up to 180 will get mapped to whatever values that produces a pulse width between Minimum_pulse and Maximum_Pulse and all depends on the PWM resolution itself.
How to generate PWM signal on STM32F103?
Probably the easiest solution is to use one of the timer which can generate PWM signals, like TIM1-3 on an STM32F103. For a modern digital servo the frame rate can go down to 5 ms or so, but for an old analog servo it should be 20 ms or 50 Hz.