pbio/drivebase: Update changed control settings.

New control settings were introduced in the previous commit, so drive
bases must get appropriate values too or we get undefined behavior.

Now we can also drop the "hack" of dividing the proportional gain by
four, which was originally done to make drivebases run smoother at low
speeds. This is now accomplished by handling low speed in the controllers
explicitly.

Author: laurensvalk

lib/pbio/src/drivebase.c

@@ -63,13 +63,16 @@ static void drivebase_adopt_settings(pbio_control_settings_t *s_distance, pbio_c
     s_distance->deceleration = pbio_int_math_min(s_left->deceleration, s_right->deceleration) * 3 / 4;
 
     // Use minimum PID of both motors, to avoid overly aggressive control if
-    // one of the two motors has much higher PID values. For proportional
-    // control, take a much lower gain. Drivebases don't need it, and it makes
-    // for a smoother ride.
-    s_distance->pid_kp = pbio_int_math_min(s_left->pid_kp, s_right->pid_kp) / 4;
+    // one of the two motors has much higher PID values.
+    s_distance->pid_kp = pbio_int_math_min(s_left->pid_kp, s_right->pid_kp);
     s_distance->pid_kd = pbio_int_math_min(s_left->pid_kd, s_right->pid_kd);
 
-    // Integral control is not necessary since there is constant external
+    // Use the same thresholds for reduced proportional gain.
+    s_distance->pid_kp_low_pct = pbio_int_math_min(s_left->pid_kp_low_pct, s_right->pid_kp_low_pct);
+    s_distance->pid_kp_low_error_threshold = pbio_int_math_min(s_left->pid_kp_low_error_threshold, s_right->pid_kp_low_error_threshold);
+    s_distance->pid_kp_low_speed_threshold = pbio_int_math_min(s_left->pid_kp_low_speed_threshold, s_right->pid_kp_low_speed_threshold);
+
+    // Integral control is not necessary since there is no constant external
     // force to overcome that wouldn't be done by proportional control.
     s_distance->pid_ki = 0;