To accomplish adaptive robots, we leverage mechanical design, novel materials, biological principles, and dynamic control to guide our design. Currently, we are working in the following three main areas: 1) soft robots; 2) flying robots; 3) reconfigurable robots.
Soft robots are new types of robots with deformable bodies and muscle-like actuators, which are fundamentally different from traditional robots with rigid links and motor-based actuators. We are currently working on the following issues in soft robots:
- New actuation methods for soft robots: twisted-and-coiled actuators (TCAs)
- Enable fast and strong motion with bistable/multistable mechanisms
- Shape morphing for soft robots: move and hold to another configuration
- Pawlowski, Ben, Jiefeng Sun, Jing Xu, Yingxiang Liu, and Jianguo Zhao. “Modeling of Soft Robots Actuated by Twisted-and-Coiled Actuators.” IEEE/ASME Transactions on Mechatronics (2018).
- Sun, Jiefeng, Ben Pawlowski, and Jianguo Zhao. “Embedded and Controllable Shape Morphing with Twisted-and-Coiled Actuators.” IEEE/RSJ International Conference on Intelligent Robots and Systems, 2018.
- Abbas, Ali, and Jianguo Zhao. “A physics based model for twisted and coiled actuator.” In Robotics and Automation (ICRA), 2017 IEEE International Conference on, pp. 6121-6126. IEEE, 2017.
Although aerial robots are widely used for various civilian and military applications, they suffer universally from a limited airborne time (less than one hour) due to the low aerodynamic efficiency and high energy consumption. To address this problem, perching onto objects (e.g., walls, power lines, or ceilings) will significantly extend aerial robots’ functioning time as they can save or even harvest energy after perching, while also maintaining a desired altitude and orientation for surveillance or monitoring.
This project aims to enable perching capabilities for palm-size flying robots by integrating both computational and mechanical intelligence. For computational intelligence, we are using onboard vision systems to estimate the required parameters (e.g., time -to-contact) for perching. For mechanical intelligence, we are developing compliant legs enabled by bistable mechanisms for effectively attaching to desired objects.
- Zhang, Haijie, Bo Cheng, and Jianguo Zhao. “Optimal trajectory generation for time-to-contact based aerial robotic perching.” Bioinspiration & biomimetics 14, no. 1 (2019): 016008.
- Zhang, Haijie, and Jianguo Zhao. “Bio-inspired vision based robot control using featureless estimations of time-to-contact.” Bioinspiration & biomimetics 12, no. 2 (2017): 025001.
Most of traditional robots can only use its body parts for a specific function, limited by the fixed mechanical design. However, it would be interesting to leverage the same structure for different functions, especially for small-scale robots owing to their limited sizes and weights. In this project, we aim to investigate how to embed variable stiffness material into mechanical mechanisms to enable stiffness-controllable joints. Such a strategy can change the configuration of the mechanisms to generate different trajectories.
- Sun, Jiefeng, and Jianguo Zhao. “An Adaptive Walking Robot with Reconfigurable Mechanisms using Shape Morphing Joints”, Accepted to IEEE Robotics and Automation Letters, 2019.
- DeMario, Anthony, and Jianguo Zhao. “Development and Analysis of a Three-Dimensional Printed Miniature Walking Robot With Soft Joints and Links.” Journal of Mechanisms and Robotics 10, no. 4 (2018): 041005.