I am a robotics researcher and interested to develop practical and human-centered technology through robotics and AI to change the world for good. My research interest mainly includes whole body control, dynamics control, Supernumerary robotic limb, humanoid and quadruped locomotion. Below is my background:
2024 Associate Professor, Sun Yat-sen University.
2022-2023 Assistant Director, Intelligent Autonomous Driving Center, HKUST, GZ.
2021 PostDoc, Massachusetts Institute of Technology. With Prof. Harry Asada
2019~2020 PostDoc, University of Science and Technology of China
2014~2018 PhD, State Key Laboratory of Robotics and System, HIT
With Prof. Shuguo Wang & Prof. Yili Fu
2016~2018 Visiting Scholar, Stanford Robotics Lab, Stanford University. With Prof. Oussama Khatib
Feb~May 2017 Short-term visitor, Human Centered Robotics Lab, UT Austin. With Prof. Luis Sentis
2012~2014 M.A., State Key Laboratory of Robotics and System, HIT
Sep~Dec 2010 Exchange student, ME Dept, The University of Hong Kong
2008~2012 B.E., Honor School, HIT
I designed a 50 kg electrically-actuated quadruped robot, Kirin, seeking to leverage the payload carrying capability. Kirin is an characterized with prismatic quasi-direct-drive (QDD) leg. This mechanism greatly augments the payload carrying capability. This study presents several design principles for the payload-carrying-oriented quadruped robots, including the mechanical design, actuator parameters selection, and locomotion control method. The theoretical analysis implies that the lifting task tends to be a bottleneck for the existing robots with the articulated knee joints. By using prismatic QDD leg, the payload carrying capability of Kirin is enhanced greatly. To demonstrate Kirin’s payload carrying capability, in preliminary experiment, up to 125 kg payload lifting in static stance and 50 kg payload carrying in dynamic trotting are tested. Whole body compliance with payload carrying is also demonstrated. Theoretically, Kirin is design to be able to carry more than 500 kg.
To accomplish autonomous locomotion navigation in complex environments, spinning is a fundamental yet indispensable functionality for legged robots. However, spinning behaviors of quadruped robots on uneven terrain often exhibit position drifts. Motivated by this problem, this study presents an algorithmic method to enable accurate spinning motions over uneven terrain and constrain the spinning radius of the center of mass (CoM) to be bounded within a small range to minimize the drift risks. A modified spherical foot kinematics representation is proposed to improve the foot kinematic model and rolling dynamics of the quadruped during locomotion. A CoM planner is proposed to generate a stable spinning motion based on projected stability margins. Accurate motion tracking is accomplished with linear quadratic regulator (LQR) to bind the position drift during the spinning movement.
Since Mar 2020 through Dec 2020, I collaborated with Prof. Harry Asada on Supernumerary Robotic Limb (SuperLimb). As shown in the figures, we studied a control method to regulate the supporting forces of SuperLimb in overhead tasks through sEMG signals and whole body kinematics and dynamics control framework. This research work has been published in IEEE ASME/AIM workshop. Another submission is currently under review for RA-L and ICRA 2021.
Since Jan 2019 through Aug 2019, I worked on CoM and CoP trajectory estimation based on integration of wearable visual odometry and walking model. Visual odometry device is worn in the front chest and provides CoM estimation. CoP is estimated through optimization derived from walking model. This study is published on IEEE-TASE.
Since Aug 2019 to present, I built a quadruped robot. It is for my hobby. I designed the mechanical structure and 3D-printed most parts. I customerized QDD motor for the joints. I am pretty curious how stable the four-legged locomotion can be.
At current stage, a preliminary test is conducted for swing phase. Position control is set in the outer loop. Video shows that swing leg can track accurate trajectory. Compliance contact with ground is to be tested for GRF regulation.
Since 2012 through 2016 (during my master and PhD), I designed and built three biped robot platforms, which were supported by funding from national science foundation. I finished my PhD research in biped robot system design and whole-body operational space control.
The robots in the left and middle figures have 12 DoFs for 3D walking experiment. The right one is a planar robot with SEA joint for quasi-passive stable walking experiment purpose. The height of hip joint of all these robots is around 0.8 m (roughly human size). Walking gait based on LIPM and MPC was tested in experiment as shown in YouTube. Angular momentum, especially for yaw axis, is also integrated in control framework.
Please find more, including simulation videos, on my YouTube channel :
https://www.youtube.com/channel/UCan7uslmleVZzJPavKcO7oA?view_as=subscriber
Since Feb 2017 through May 2017, I worked with Prof. Luis Sentis on the hierarchical control structure, where Whole-Body Operational Space (WBOS) controller works in the middle level for biped locomotion. WBOS is able to decouple various tasks and provide analytical solution (so that real-time computation) to inverse dynamics with the single or double feet contact constraints. In high level, prismatic inverted pendulum model is explored for CoM trajectory planning.
Since May 2018 through Aug 2018, I built a wheeled robot with active-driven yaw axis. The robot is able to turn at zero radius. Suspension structure is integrated in the robot.
The platform aims on research of terrain perception using visual odometry and 3D SLAM.