diff --git a/src/segway_rmp200.cpp b/src/segway_rmp200.cpp
index 41af963fd2f1c01befb1d129b8b59d4bb4e2396d..fc0f7143cabe777819e49f8f40f48e57ddd539fa 100755
--- a/src/segway_rmp200.cpp
+++ b/src/segway_rmp200.cpp
@@ -430,6 +430,13 @@ void CSegwayRMP200::command_thread(void)
       packet.data[15]=command[2];
       packet.data[16]=command[3];
     }
+    else
+    {
+      packet.data[13]=0x00;
+      packet.data[14]=0x00;
+      packet.data[15]=0x00;
+      packet.data[16]=0x00;
+    }
     this->access_command.exit();
     packet.data[17]=this->compute_checksum(&packet);
     try{