Robot.set_value(device, param) for Lowcar Devices

Servo Controller

Servo Controller sets a value associated with the device and param specified.

The device being specified is a Servo.

param for a Servo:

  • "servo0"
  • "servo1"

Changing values for the servo spins the servo to an angle based on the value entered. The values -1 and 1 each refer to the maximum position of the servo in one direction. For example, if we described our minimum position to be 0°, and our maximum to be 180°, then 1 would set the servo to 180°, -1 would set the servo to 0°, and -0.5 would set it to be 45°.

Sample Usage:

# sets the current angle of servo0 to 180°
Robot.set_value(servo_id, "servo0", 1)

KoalaBear

KoalaBear sets a value associated with the device and param specified.

The device being specified is a YogiBear.

parameters for a YogiBear:

Motor A

  • "velocity_a"
  • "deadband_a"
  • "invert_a"
  • "pid_enabled_a"
  • "pid_kp_a"
  • "pid_ki_a"
  • "pid_kd_a"
  • "enc_a"

Motor B

  • "velocity_b"
  • "deadband_b"
  • "invert_b"
  • "pid_enabled_b"
  • "pid_kp_b"
  • "pid_ki_b"
  • "pid_kd_b"
  • "enc_b"

Motor control is handled through changing the values of "velocity_a" and "deadband_a".

  • "velocity" which sets a float from -1 to 1 which describes the direction the motor is turning and it's power.
  • "deadband" which sets the threshold that velocity must pass before a change is made to "velocity"

The encoder's value can be set using the "enc" parameter. Setting the "enc" count allows for someone to change the number of ticks recorded from the encoder.

PiD Control includes:

  • "pid_kp", "pid_ki", and "pid_kd" parameters which set the proportional, integral, and derivative coefficients on the motor controller. Each of these values have to be above zero.
  • "pid_enabled" parameter sets whether or not pid is enabled for a motor.

Sample Usage:

# sets the current speed of Motor A to max speed
Robot.set_value(motor_id, "velocity_a", 1)