SWhegPro3 Wheel-Leg Transformable Robot
- Role -
- Lead Student Researcher, ROMA Lab
- Date -
- October 24, 2024
- Stack —
- Wheel-Leg Robot, Mechanical Design, Locomotion, ROS, MATLAB
A four-module mobile robot with transformable three-impeller wheels for robust stair climbing across varied dimensions.
Research question
Wheeled robots are efficient on flat ground but struggle on discontinuous terrain, while legged robots gain mobility at the cost of complexity and efficiency. SWhegPro3 explores a compact middle ground: each wheel can expand into a three-impeller leg for indoor stair climbing and retract for normal rolling.
My contribution
I independently developed the SWhegPro3 platform as an undergraduate researcher and first author. My work covered:
- Mechanical design, assembly, and iteration of the four-module robot.
- Selection and optimization of wheel geometry and wheelbase for common stair dimensions.
- MATLAB modeling and simulation of stair-climbing kinematics and front-rear wheel phase behavior.
- ROS-based system integration, gait-control experiments, and performance analysis.
- Preparation of the ROBIO 2023 paper and the broader field-transportation study.
Design and control
The transformable modules use self-locking electric push rods instead of a gear or tendon transmission. The resulting triangular support structure holds its geometry under load, while slip rings provide power and signals to actuators mounted on the rotating wheels.
Kinematic optimization produced a 510 mm wheelbase for the target stair geometry. Simulation also showed that four modules avoided the redundant high-frequency motion observed in a six-wheel configuration. During stair climbing, the front wheels provide the main drive and the rear wheels assist under torque limits; the expandable rim geometry can be adjusted for different stair dimensions.
Results
The completed robot climbed stairs spanning approximately 15 to 32 degrees, reached a maximum climbing speed of 1.8 steps per second, and carried a 7 kg payload in testing. The work led to a first-author paper at IEEE ROBIO 2023 and a 2024 arXiv paper on robust wheel-leg field transportation robots.
Publications
- H. Wang, S. Wang, C. Dai, and Z. Jia, “SWhegPro3: A Three-Impeller Wheel-Leg Transformable Robot with Variable Robust Adaptability to Stair Dimensions,” IEEE ROBIO, 2023.
- H. Wang et al., “Ubiquitous Field Transportation Robots with Robust Wheel-Leg Transformable Modules,” arXiv:2410.18507, 2024.