diff --git a/robomaster_pi/conn_vel.py b/robomaster_pi/conn_vel.py
index 96ef07915004714dc4e1ee5e9858d1ff59d393a6..49e2b8d32807afc35042348dbbef1890fdf6b7e6 100644
--- a/robomaster_pi/conn_vel.py
+++ b/robomaster_pi/conn_vel.py
@@ -32,7 +32,7 @@ class vel_from_ros_node(Node):
         self.get_vel_from_ros_ = self.create_subscription(Twist, "/cmd_vel", self.pose_callback, 10)
 
 
-    def check_connection():
+    def check_connection(args):
         print("ja")
         self.response = self.isConnected()
         if(self.response != True):