From ec79b2f8c86265baaeddc008bb2de0fc7e7e3bdc Mon Sep 17 00:00:00 2001
From: Dennis Mannhart <dennis@yuneecresearch.com>
Date: Mon, 19 Feb 2018 10:53:15 +0100
Subject: [PATCH] ControlMath: don't consider sign when vector length is 0

---
 src/modules/mc_pos_control/Utility/ControlMath.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/modules/mc_pos_control/Utility/ControlMath.cpp b/src/modules/mc_pos_control/Utility/ControlMath.cpp
index 6fa4cc0884..cfc987002c 100644
--- a/src/modules/mc_pos_control/Utility/ControlMath.cpp
+++ b/src/modules/mc_pos_control/Utility/ControlMath.cpp
@@ -154,7 +154,7 @@ void constrainPIDu(matrix::Vector3f &u, bool stop_I[2], const float Ulimits[2],
 		 * since we do not know better. (no direction given)
 		 */
 		if (u.length() < 0.0001f) {
-			u = matrix::Vector3f(0.0f, 0.0f, math::sign(u(2)) * Ulimits[1]);
+			u = matrix::Vector3f(0.0f, 0.0f, -Ulimits[1]);
 
 		} else {
 			u = u.normalized() * Ulimits[1];