Safety-Critical Centralized Nonlinear MPC for Cooperative Payload Transportation by Two Quadrupedal Robots
Ruturaj S. Sambhus, Yicheng Zeng, Kapi Ketan Mehta, Jeeseop Kim, Kaveh Akbari Hamed
TLDR
A safety-critical NMPC framework enables two quadrupedal robots to cooperatively transport payloads, ensuring collision avoidance.
Key contributions
- Develops a safety-critical centralized NMPC for cooperative payload transport by two quadrupeds.
- Models the robot-payload system as a discrete-time nonlinear DAE, capturing coupled dynamics.
- Employs CBF-based NMPC to enforce collision avoidance for both robots and the payload.
- Validated on Unitree Go2 robots in cluttered environments with uncertainties and disturbances.
Why it matters
This paper advances cooperative robotics by presenting a robust NMPC framework for multi-quadruped payload transport. Its safety-critical design, validated on hardware, enables reliable operation in complex, uncertain environments.
Original Abstract
This paper presents a safety-critical centralized nonlinear model predictive control (NMPC) framework for cooperative payload transportation by two quadrupedal robots. The interconnected robot-payload system is modeled as a discrete-time nonlinear differential-algebraic system, capturing the coupled dynamics through holonomic constraints and interaction wrenches. To ensure safety in complex environments, we develop a control barrier function (CBF)-based NMPC formulation that enforces collision avoidance constraints for both the robots and the payload. The proposed approach retains the interaction wrenches as decision variables, resulting in a structured DAE-constrained optimal control problem that enables efficient real-time implementation. The effectiveness of the algorithm is validated through extensive hardware experiments on two Unitree Go2 platforms performing cooperative payload transportation in cluttered environments under mass and inertia uncertainty and external push disturbances.
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