Virtual Model Control for Suppressing Vibrations in Wheeled Quadruped Robots Traversing Speed Bumps

This paper explores the use of Virtual Model Control (VMC) to suppress vibrations in a Wheeled Quadruped Robot (WQR) as it traverses speed bumps. The WQR combines the mobility of wheels with the flexibility of legged movement, facing challenges in maintaining stability and minimizing vibrations during such maneuvers. To address these issues, a VMC strategy inspired by vehicle passive suspension principles is developed and applied. The WQR’s center of mass coordinates relative to its body coordinate system are calculated, and specific VMC stiffness is assigned for the front legs and hind legs based on these coordinates. As the WQR traverses speed bumps, the VMC control parameters are dynamically adjusted according to the roll and pitch angles measured by an Inertial Measurement Unit (IMU) mounted on the WQR’s torso. Simulation results confirm the effectiveness of the proposed method, showing significant reductions in vibration amplitudes compared to a fixed joint angle control strategy. This study advances control techniques for WQRs, enhancing their performance and stability in real-world applications. Future work will focus on optimizing VMC parameters and extending this approach to more complex terrains and dynamic scenarios.