Design of a Control System for a Wheeled-Legged Amphibious Robot Based on Super-Helical Sliding Mode Control.

Introduction

🌞 Aims:

  1. Design and production of physical prototypes of wheeled-legged robot.
  2. Design a effective balance control algorithm based for the designed wheeled-legged robot.

📝 Advisor: Prof. Yifei Wu

📅 Duration: Feb. 2023 - Mar. 2023

Contributions

  1. Conducted forward and inverse kinematics analysis of the robot using the D-H method, and established kinematic and dynamic models considering joint center of mass constraints.
  2. Designed a super-helical sliding mode balance controller based on the robot modeling results, and verified the balance algorithm through simulations in Simulink.
  3. Designed and developed the robot’s hardware circuitry. Built an air-ground integrated experimental prototype of the robot.

Conclusion

Concluded that the designed balance controller quickly converges to the desired position or speed, exhibits strong disturbance rejection during air-to-ground transitions, and maintains robustness when the robot’s height changes.

Outcomes

  1. A patent (A Wheel-Legged Air-Ground Integrated Robot Based On Super-Spiral Sliding Form.)
  2. An experimental prototype of the robot

Project Showcase

Conceptual diagram of the robot design:


Hardware circuitry for the robot’s wheel leg section:

The designed amphibious air-ground robot:



Mathematical model of the robot

The balancing of the robot involves only position and inclination control.

Using $x$ and $\phi$ represent the position and inclination of the robot, $C_l$ and $C_r$ represent the left and right motor torque, we can get the mathematical model of the robot as following

(More details are coming soon …)

Partial simulation results:

The targst position is 1m and the initial inclination is $\frac{\pi}{4}$:

The targst velocity is 1m/s and the initial inclination is $\frac{\pi}{4}$:

The immunity is tested by equating the instant of air-ground mode switching to a perturbation signal: