Stable yuntai core is to allow each axis motor generates the twist appropriate upwards, yuntai motor, to offset the relative to a stable platform on the direction of movement. So for such a control model, the input is the platform attitude itself relative to the external frame of reference (General is gravity)Change, is the control motor output (Control platform attitude change)。 So to form closed-loop, system will perceive its axial upward attitude change. For cost reasons, multi-purpose mems gyroscope and accelerometer (Angular velocity and acceleration feedback change, after fusion knowable posture change)。
of course Angle encoder can also (Feedback on changes in the Angle of each axis upward, equivalent euler Angle), but more expensive, and large size. Now know the control object and feedback, the next thing to do is through the control algorithm, such as pid closed-loop control. In order to achieve stable, easy to get, we need to get the stable platform of relative gravity posture change & other; Lock & throughout; To zero, so the object of the closed loop is obviously platform attitude changes in relative gravity direction difference Error (Can be perspective, also can not Angle, mathematics of posture sensor data processing method has a quaternion, dongguan dc brushless motor, the direction cosine matrix, euler angles and so on, point of view, the essence is a kind of equivalent)。 Insert here, the vast majority of static electricity are need to keep on open yuntai platform for a period of time, is actually use the time calibration gravity direction, avoid force effect on the accelerometer and gyroscope. So obviously, for a single axis (X/y/z axis), using pid complete closed-loop control object is: the Output = Kp * Error + Ki * & sum; The Error + Kd * dError/dt other two axis in the same way.
in general is the Output to the motor PWM (Adjust the motor speed indirectly control the output torque), if you have the brush motor with motor driver chip control, software part it so far (But the word of brushless didn't! )。 But if you're going to take a half bridge/full drive, also need to know about the motor/half bridge bridge driving circuit, and brushless motor drive mode. Namely with three-phase electric circuit, MCU brushless motor, the principle of electronic governor. Just say so many, brushless motor drive part and filling holes in the future. When it comes to this step in fact already very mindless, yuntai this kind of thing is not very complicated.
