🤖 AI Summary
This work addresses the challenges of pose drift and control instability in large-scale mobile robots operating on loose, slippery terrain due to insufficient traction. To this end, a four-module cooperative framework is proposed, integrating stereo-vision-based pose estimation, high-order nonlinear model predictive control (NMPC), a deep neural network-based low-level controller, and a logarithmic barrier-based safety monitoring mechanism. The approach uniquely combines high-order NMPC with a learning-based low-level controller and introduces a logarithmic safety barrier, achieving system-wide safety and exponential stability of actuators through synchronized multi-rate heterogeneous module coordination. Experimental validation on a 6,000-kg dual electro-hydrostatic actuation platform demonstrates that the method enables low-latency, high-precision pose tracking and full-stack safety guarantees under severe slippage conditions.
📝 Abstract
A large-scale mobile robot (LSMR) is a high-order multibody system that often operates on loose, unconsolidated terrain, which reduces traction. This paper presents a comprehensive navigation and control framework for an LSMR that ensures stability and safety-defined performance, delivering robust operation on slip-prone terrain by jointly leveraging high-performance techniques. The proposed architecture comprises four main modules: (1) a visual pose-estimation module that fuses onboard sensors and stereo cameras to provide an accurate, low-latency robot pose, (2) a high-level nonlinear model predictive control that updates the wheel motion commands to correct robot drift from the robot reference pose on slip-prone terrain, (3) a low-level deep neural network control policy that approximates the complex behavior of the wheel-driven actuation mechanism in LSMRs, augmented with robust adaptive control to handle out-of-distribution disturbances, ensuring that the wheels accurately track the updated commands issued by high-level control module, and (4) a logarithmic safety module to monitor the entire robot stack and guarantees safe operation. The proposed low-level control framework guarantees uniform exponential stability of the actuation subsystem, while the safety module ensures the whole system-level safety during operation. Comparative experiments on a 6,000 kg LSMR actuated by two complex electro-hydrostatic drives, while synchronizing modules operating at different frequencies.