optimize support for lite6, add specific ReadMe

ReadMe.md

@@ -1,6 +1,9 @@
 For simplified Chinese version: [简体中文版](./ReadMe_cn.md)    
+For UFACTORY Lite 6 users, make sure you have followed the instructions before chapter 4.7 on this page, then switch to [ReadMe for other UFACTORY models](./ReadMe_others.md).  
 
 ## Important Notice:
+  Topic "**xarm_cgpio_states**" has been renamed to "**controller_gpio_states**".  
+
   After using xArm C++ SDK as sub-module, the use of **/xarm/set_tool_modbus** service has been modified, compared with old version, the redundant '***0x09***' byte in response data has been ***removed***！  
   Due to robot communication data format change, ***early users*** (xArm shipped ***before June 2019***) are encouraged to ***upgrade*** their controller firmware immediately to drive the robot normally in future updates as well as to use newly developed functions. Please contact our staff to get instructions of the upgrade process. The old version robot driver can still be available in ***'legacy'*** branch, however, it will not be updated any more.   
 

ReadMe_others.md

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+# Important Notice:
+This ReadMe is for new(Lite 6) and future UFACTORY product models other than xArm series. Here use "lite6" as example.  
+
+If you have used "xarm_ros" for xArm series before, the main differences for new UFACTROY models are:  
+
+* Default namespace has changed from `xarm` to `ufactory`;  
+
+* Robot full-state report topic name has changed from `xarm_states` to `robot_states`;   
+
+
+# 1. Simulations
+
+## 1.1 Simple Rviz visualization:  
+```bash
+$ roslaunch xarm_description lite6_rviz_display.launch
+```
+The robot model will appear in Rviz window and "joint state publisher" panel can be used to adjust the posture of that robot.  
+
+
+## 1.2 Load robot model in Gazebo environment:
+```bash
+$ roslaunch xarm_gazebo lite6_beside_table.launch [add_gripper:=true] [add_vacuum_gripper:=true] 
+```
+Gazebo will be launched and virtual robot will be mounted on a table, `add_gripper` and `add_vacuum_gripper` are optional arguments. However, only one end tool should be installed.  
+
+## 1.3 Moveit simulation:
+
+### Without Gazebo:
+```bash
+$ roslaunch lite6_moveit_config demo.launch [add_gripper:=true] [add_vacuum_gripper:=true]
+```
+### With Gazebo:
+In the first terminal, run:
+```bash
+$ roslaunch xarm_gazebo lite6_beside_table.launch [add_gripper:=true] [add_vacuum_gripper:=true] 
+```
+Then in another terminal:
+```bash
+$ roslaunch lite6_moveit_config lite6_moveit_gazebo.launch [add_gripper:=true] [add_vacuum_gripper:=true] 
+```
+In this way, the simulated robot in gazebo can execute planned trajectory generated by Moveit. 
+
+
+# 2. Controlling Real Robot
+
+# 2.1 ROS service control:
+First bring up the UFACTORY ros driver:
+```bash
+$ roslaunch xarm_bringup lite6_server.launch robot_ip:=192.168.1.xxx (your robot IP)
+```
+Then, please refer to [xarm_api/xarm_msgs part](https://github.com/xArm-Developer/xarm_ros#57-xarm_apixarm_msgs), the conceptsm provided services or messages are all the same except the **default namespace for non-xArm series** is `ufactory` rather than `xarm`. For example, to call the service of enabling all joints:
+```bash
+$ rosservice call /ufactory/motion_ctrl 8 1
+```
+All the xArm services (joint/cartesian motion, velocity motion, servo motions, etc) including [mode operations](https://github.com/xArm-Developer/xarm_ros#6-mode-change) can be directly used on new models like Lite 6, just replace previous namespace `/xarm` with `/ufactory`. 
+
+# 2.2 Moveit control:
+First make sure the robot and controller box are powered on, then execute:
+```bash
+$ roslaunch lite6_moveit_config realMove_exec.launch robot_ip:=192.168.1.xxx [add_gripper:=true] [add_vacuum_gripper:=true]
+```
+`add_gripper` and `add_vacuum_gripper` are optional available arguments if you have installed UFACTORY provided tool accessory. Only one end tool shall be installed. Below is the network diagram from `rqt_graph` output:
+![uf_moveit_rqt_graph](./doc/uf_moveit_rqt_graph.png)