Minor changes to execute to algorithm to go downstairs.

darwin_controller/include/darwin_controller_impl.h

@@ -716,7 +716,10 @@ namespace darwin_controller
     void DarwinController<HardwareInterface>::stairs_startCallback(const humanoid_common_msgs::humanoid_stairsGoalConstPtr& goal)
     {
       ROS_INFO("CDarwinSim : start climbing stairs ");
-      stairs_start();
+      if(goal->up)
+        stairs_start(0x01);
+      else
+        stairs_start(0x00);
     }
 
   template <class HardwareInterface>