Difference between revisions of "Controllers"

From Bike Wiki
Jump to navigation Jump to search
(Front Motor Controller)
(Front Motor Controller)
Line 8: Line 8:
 
===Front Motor Controller===
 
===Front Motor Controller===
 
*The front motor controller works to minimize the angle between the current steer angle (δ) and the commanded steer angle (δ<sub>c</sub>).
 
*The front motor controller works to minimize the angle between the current steer angle (δ) and the commanded steer angle (δ<sub>c</sub>).
*Currently (Spring 2018), the front motor controller is PD (Proportional-Derivative)
+
*Currently (Spring 2018), the front motor controller is PD (Proportional-Derivative) controller. Specifically,
controller. Specifically,
 
 
total_error = k<sub>p</sub>(δ<sub>c</sub> − δ) + k<sub>d</sub>d/dt(δ<sub>c</sub> − δ).
 
total_error = k<sub>p</sub>(δ<sub>c</sub> − δ) + k<sub>d</sub>d/dt(δ<sub>c</sub> − δ).
 
*total_error is converted into a direction (DIR) and a magnitude (motor_output).
 
*total_error is converted into a direction (DIR) and a magnitude (motor_output).

Revision as of 23:45, 27 March 2019

Intro

  • The control algorithms on our bicycle are separated into three cascaded controllers. The output of one controller is input to another controller.
  • In order from high level to low level:
  1. Navigation controller, which tries to follow a desired path
  2. Balance controller, which tries to achieve a desired lean angle (φd) and desired steer angle (δd). For straight line balance (no navigation), this controller attempts to achieve φd = 0 and δd = 0. In this position, the bicycle is balanced (upright and steered straight ahead).
  3. Front motor controller, which controls front wheel angle (δ).
  • Using cascaded controllers allows us to develop each controller semi-independently.

Front Motor Controller

  • The front motor controller works to minimize the angle between the current steer angle (δ) and the commanded steer angle (δc).
  • Currently (Spring 2018), the front motor controller is PD (Proportional-Derivative) controller. Specifically,

total_error = kpc − δ) + kdd/dt(δc − δ).

  • total_error is converted into a direction (DIR) and a magnitude (motor_output).

Balance Controller

Euler Integrator