Renamed some variables to clarify functionality.

ArduCopter/Attitude.pde

@@ -269,38 +269,28 @@ get_rate_yaw(int32_t target_rate)
 static int16_t
 get_nav_throttle(int32_t z_error)
 {
-	//static int16_t old_output = 0;
-	int16_t rate_error = 0;
+	int16_t z_rate_error = 0;
+	int16_t z_target_speed = 0;
 	int16_t output = 0;
 
 	// convert to desired Rate:
-	rate_error 		= g.pi_alt_hold.get_p(z_error);
-	rate_error 		= constrain(rate_error, -250, 250);
+	z_target_speed 		= g.pi_alt_hold.get_p(z_error);
+	z_target_speed 		= constrain(z_target_speed, -250, 250);
 
 	// limit error to prevent I term wind up
 	z_error 		= constrain(z_error, -400, 400);
 
 	// compensates throttle setpoint error for hovering
-	int16_t iterm = g.pi_alt_hold.get_i(z_error, .02);
+	int16_t i_hold 	= g.pi_alt_hold.get_i(z_error, .02);
 
 	// calculate rate error
-	rate_error 		= rate_error - climb_rate;
-
-	// hack to see if we can smooth out oscillations
-	//if(rate_error < 0)
-	//	rate_error = rate_error >> 1;
+	z_rate_error 	= z_target_speed - climb_rate;
 
 	// limit the rate
-	output =  constrain(g.pid_throttle.get_pid(rate_error, .02), -80, 120);
-
-	// light filter of output
-	//output = (old_output + output) / 2;
-
-	// save our output
-	//old_output  = output;
+	output =  constrain(g.pid_throttle.get_pid(z_rate_error, .02), -80, 120);
 
 	// output control:
-	return output + iterm;
+	return output + i_hold;
 }
 
 // Keeps old data out of our calculation / logs