2018-10-13 星期六

The high level of English is a standard for a top student.

1. If you smile, even if you’re in a bad mood, it will immediately improve your mood.

2. True mastery of any skill takes a lifetime. ​​​​

3. What do you think of the traffic in your city

Well, I think it's terrible, especially during rush hours. The traffic could get so heavy, everywhere would be jammed. You won’t be able to turn around or turn back. But I guess I can’t complain because I think our situation is way better than the situations in bigger cities such as Beijing and Shanghai. After all, my city is, what we call, a second-tier city or even a third-tier city, depending on where you're sitting. In addition, the government has been working on it. We have built express ways and the subway to alleviate the problems and I believe things will pick up.

4. Vanity and pride are different things, though the words are often used synonimously. A person may be proud without being vain. vanity to what we would have others think of us.

5. You may never be good enough for some people, but you will always be the best for those who deserve you.

6. Life is too short to worry about what others say or think about you. So have fun and give them something to talk about.

7. I am always doing that which I can not do, in order that I may learn how to do it. 

8. Everyone has his own direction to pursue, do not be taken away from the rhythm, to restart a section of the road before you must do a construction of their own hearts, whether the future is better or worse, is just another day. Will there be no end to the end? We are always on the road.

9. Love has made me see things in a different way

10. Direction is much more important to speed.

11. Living is to change the world. Is there any other reason?

12. Language is the medium of affective communication and information transfer.

paper

 1. ROS based service robot platform (https://ieeexplore.ieee.org/document/8384644)

(https://sci-hub.tw/10.1109/iccar.2018.8384644)

Abstract:

The substitution of a human factor by an affordable low-cost robotic system has been increasing recently.(background) The reason being, the robot is expected to do less errors than a human does and does not have a will of its own. This paper proposes a service robot platform that is capable of mapping, localizing itself and navigating in an indoor environment and is best suited for structured environment with static obstacles. The approach used for mapping is a ROS package which is a ROS wrapper of Real Time Appearance Based Mapping with the help of a low cost RGB-D camera, the Microsoft Kinect XBOX 360 with a turtlebot robot model for visualization. RTAB-Map takes into account loop closure in real time constraints with a memory management technique which makes the mapping process independent of time and size. Once the mapping is done and the 2D projection of the map is obtained of our real indoor environment of the lab, the simulation of the autonomous navigation of the robot model to the desired location is done on Gazebo. For the navigation to happen successfully, Adaptive Monte Carlo Localization is used for localizing the turtlebot model in the map. The simulation results were visualized using rviz and were found to be satisfactory.

Gazebo Tutorials

1. Make a model (http://gazebosim.org/tutorials?tut=build_model&cat=build_robot)

2. Make a Mobile Robot （http://gazebosim.org/tutorials?tut=build_robot&cat=build_robot）

1. mkdir -p ~/.gazebo/models/my_robot

2. gedit ~/.gazebo/models/my_robot/model.config

3. gedit ~/.gazebo/models/my_robot/model.sdf

 

3. Model structure and requirements （http://gazebosim.org/tutorials?tut=model_structure&cat=build_robot）

4. Building a world （http://gazebosim.org/tutorials?tut=build_world&cat=build_world#AddingModelfromtheModelDatabase）

Terminology

• World: The term used to describe a collection of robots and objects (such as buildings, tables, and lights), and global parameters including the sky, ambient light, and physics properties.
• Static: Entities marked as static (those having the <static>true</static> element in SDF), are objects which only have collision geometry. All objects which are not meant to move should be marked as static, which is a performance enhancement.
• Dynamic: Entities marked as dynamic (either missing the <static> element or setting false in SDF), are objects which have both inertia and a collision geometry.

5. Modifying a world （http://gazebosim.org/tutorials/?tut=modifying_world）

6. Visibility layers （http://gazebosim.org/tutorials?tut=visual_layers&cat=build_robot）

7. Inertial parameters of triangle meshes （http://gazebosim.org/tutorials?tut=inertia&cat=build_robot）

8. Make an animated model (actor) （http://gazebosim.org/tutorials?tut=actor&cat=build_robot）（amazing!）

Overview

 

This tutorial explains how to use Gazebo's "actors" to create scripted animations.

 

Animations are useful if you want to have entities following predefined paths in simulation without being affected by the physics engine. This means they won't fall due to gravity or collide with other objects, for example. They will, however, have a 3D visualization which can be seen by RGB cameras, and 3D meshes which can be detected by GPU based depth sensors.

 

The tutorial explains in detail how to create open-loop trajectories which don't interact with the rest of the simulation. Towards the end, we will take a quick look at an example plugin which controls animations based on feedback from the environment.

Skeleton animation, which is relative motion between links in one model:

Motion along a trajectory, which carries all of the actor's links around the world, as one group:

Both types of motions can be combined to achieve a skeleton animation which moves in the world:

 

 ROS Robot instance -Turtlebot  (https://zhuanlan.zhihu.com/p/35822939)