Cost Learning and Path Planning

Apr, 2014 - Apr, 2014

Team Members: Chao Liu

  • Built a route planner for the Penn Campus;
  • Selected a bag of features based on a high resolution aerial photograph and generate the training set by labelling the paths which are reasonable;
  • Implemented reinforcement learning method to learn the cost associated with each feature;
  • Used Dijkstra's algorithm to find the optimal path;

Simultaneous Localization and Mapping

Click to the project link

Mar, 2014 - Apr, 2014

Team Members: Chao Liu

  • Mapped the structure of an indoor environment using information from an IMU and LIDAR sensor on a mobile robot;
  • Pre-processed the data and used odometry measurements and yaw gyro readings to make 2D map;
  • Constructed the surrounding 2D map using a particle filter and occupancy grid algorithm with LIDAR sensor data;

PhanToM Robot Control System

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November 10, 2013 - December 20, 2013

Team Members: Chao Liu, Chenyang Zhu, Hanfei Sun

  • Designed a wearable device with EMG sensors(read muscle signals) and an IMU to measure the muscle activation and motion to control robots;
  • Designed a mobile robot with Omni-wheels and holonomic control;
  • Hacked a toy connon and placed it on the vechile robot;
  • Designed a circuit board with an IMU, an xBee and so on and a low-level PID controller for a quadrotor;
  • Controlled the vehicle robot to shoot the quadrotor by the wearable devices.

Yelp Rating Prediction

November 20, 2013 - December 10, 2013

Team Members: Chao Liu, Jianqiao Li, Shuotian Chen

  • Process user reviews with NLP methods to know more properties of the words;
  • Used Naïve Bayes, SVM and our own kernel to train the data and got a model.

Persona Robot

Click to the project link

July 2013 - August 2013

Team Members: Jay Davey, Chao Liu, Yanwei Du, Gabby, Uriah, Seethu, Chatty

  • Designed a infrared-based force sensor and associated PCB;
  • Implemented a servo controller for tablet-driven motors;
  • Designed PID controllers for the base motion and mast rotation with encoders.

M4 Peripheral Design -- mTouch

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February 2013 - March 2013

Team Members: Chao Liu

  • Used FT5306 controller for capacitive touchscreen;
  • designed the interface PCB and code for comminucation between STM32F373(Cortex-M4) and FT5306 via IIC;

Robutler

January 2013 - February 2013

Team Members: Chao Liu, Matthew Gus

  • Designed an automatic robot to deliver something from one room to another room;
  • Used 4 67:1 Metal Gearmotors and 4 Omni wheels to control the robot with holonomic control;
  • Designed a remote controller with mRF wireless module which enable the user to remotely control the robot;
  • Designed an arm and used a servo to control the arm to knock the door;

Low-cost Laser Range Finder

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December 2012 - June 2013

Team Members: Chao Liu, Bhargava Chaitanya

  • Designed a laser range finder which is a low-cost, very small, reliable and high-speed real-time device;
  • Simulated SCCB protocol on STM32F373 and configured the camera(OV7670) in Raw RGB mode with VGA resolution;
  • Made the Makefile to compile the inline assembly language and used inline assembly language to speed up the data processing;
  • Transmitted the data to the master device via SPI.

Robockey

Click to the project link

November 2012 - December 2012

Team Members: Chao Liu, Burke Kevin, Rui Zhang, Sehrawat Sukreeti

  • Competed in 3-on-3 hockey played by fully-automnomous robots;
  • Designed an algorithm to localize the robot itself in the rink with a Wii infrared camera which can take a photo of the 4 Fixed stars above the rink;
  • Implemented RF wireless communication modules to communicate with each other;
  • Designed PD controller to capture puck and move toward goad;
  • Integrated solenoid for "shooting".

PHANToM Haptics

November 2012 - December 2012

Team Members: Chao Liu, Bhargava Chatty, Dawei Wang

  • Designed a system that can make people feel an object with PHANToM(a device with joints, end-effector and encoders);
  • Simulated a ball and push the users out of the ball whenever they come inside, using a virtual spring mapping(the force should push them straight out of the ball, and the magnitude of the force should be proportional to their penetration depth);
  • Designed a system to output a viscous damping force that always acts to slow the user down(this force should act in the opposite direction to the user's velocity vector, and its magnitude should scale with the magnitude of their velocity vector);
  • Designed a filter to process the data from the encoders to make the system stable.

Puma Robot Control

October 2012 - November 2012

Team Members: Chao Liu, Chaoyi Huang, Jiali Shen

  • Calculated the forward kinematics and inverse kinematics of Puma 260 and make a kinematics program with Matlab which can calculate the position of the end-effector with 6 inputs(joint angles of 6 joints) and get the most suitable angles of 6 joints with the input(the position of the end-effector and the former angles of 6 joints);
  • Simulated the movement of Puma 260 in the Matlab and designed an algorithm to control the robot to draw a picture;
  • Controlled the real robot to draw the picture.

Acrobat

October 2012

Team Members: Chao Liu, Burke Kevin, Rui Zhang

  • Designed a robot which can be fully self-contained with only two coaxially-mounted wheels touching the ground;
  • Chose suitable motors(Pololu 47:1 25mm motor), acquired the position information of the robot with a gyro and an accelerometer(MPU6050) and Hall Effect Trans(SS494B);
  • Used Kalman Filter to process the data from the sensors and designed a PD controller to balance the robot.

Study of Rotor Shaft System Helth Monitor with Ultrasonic Guided Wave and Its Transducer

October 2011 - June 2012

Team Members: Chao Liu, Prof. Xiaoyu Wang, Prof. Daoshun Wang, Yanyan Yang

  • Applied ultrasonic guided-waves to detecting rotor systems to obtain the accurate testing data;
  • Chose microcontroller(ATmega32) and designed the circuit by Altium, including the counters(74177 & 74LS393), high speed storage device(W29C040), D/A transducer(DAC0832), DDS chip(AD9851), input keyboard(4×4) and display(12864);
  • Wrote programs to produce Ultrasonic Guided-Waves and control the input and output device.

Study on Non-Repair Dynamic Balance Device of Wheelsets in Vehicles

August 2012 - November 2011

Team Members: Chao Liu, Chao Zou, Dongju Wang, Zailin Ge

  • Ensure the dynamic balance via regulating the circumferential positions of the objects with a certain mass in the tapered groove which can avoid causing physical damage to the wheel, and extend life expectancy of wheel sets;
  • Designed and simulated testing apparatus by AutoCAD;
  • Chose piezoelectric accelerometers and established the algorithm and simulated the operation of trains;
  • Collected, filtered and amplified the signals and processed them by Visual Basic;
  • Tested the reliability of the device.

Skills and Expertise Support

Course Overview

2012 Fall

  • Foundation of Engineering Math I
  • Design of Mechatronic System
  • Introduction to Robotics

2013 Spring

  • Advanced Mechatronics
  • Design of Microelectromechanical System
  • Feedback Control Design and Analysis

2013 Fall

  • Machine Learning
  • Real Time Embedded System
  • Digital Signal Processing

2014 Spring

  • Learning in Robotics

Contact Me

Address: 3921 Pine St, Apt.2F, Philadelphia, PA
Telephone: (215)350-6662
Others: +86 186 4110 7546
E-mail:chao.liu0307@gmail.com

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