港科大 | LiDAR端到端四足机器人全向避障系统 (宇树G1/Go2+PPO)

Core Viewpoint - The article discusses the Omni-Perception framework developed by a team from the Hong Kong University of Science and Technology, which enables quadruped robots to navigate complex dynamic environments by directly processing raw LiDAR point cloud data for omnidirectional obstacle avoidance [2][4]. Group 1: Omni-Perception Framework Overview - The Omni-Perception framework consists of three main modules: PD-RiskNet perception network, high-fidelity LiDAR simulation tool, and risk-aware reinforcement learning strategy [4]. - The system takes raw LiDAR point clouds as input, extracts environmental risk features using PD-RiskNet, and outputs joint control signals, forming a complete closed-loop control [5]. Group 2: Advantages of the Framework - Direct utilization of spatiotemporal information avoids information loss during point cloud to grid/map conversion, preserving precise geometric relationships from the original data [7]. - Dynamic adaptability is achieved through reinforcement learning, allowing the robot to optimize obstacle avoidance strategies for previously unseen obstacle shapes [7]. - Computational efficiency is improved by reducing intermediate processing steps compared to traditional SLAM and planning pipelines [7]. Group 3: PD-RiskNet Architecture - PD-RiskNet employs a hierarchical risk perception network that processes near-field and far-field point clouds differently to capture local and global environmental features [8]. - The near-field processing uses farthest point sampling (FPS) to reduce data density while retaining key geometric features, and employs gated recurrent units (GRU) to capture local dynamic changes [8]. - The far-field processing uses average down-sampling to reduce noise and extract spatiotemporal features from distant environments [8]. Group 4: Reinforcement Learning Strategy - The obstacle avoidance task is modeled as an infinite horizon discounted Markov decision process, with state space including the robot's kinematic information and historical LiDAR point cloud sequences [10]. - The action space directly outputs target joint positions, allowing the policy to learn the mapping from raw sensor inputs to control signals without complex inverse kinematics [11]. - The reward function incorporates obstacle avoidance and distance maximization rewards to encourage the robot to seek open paths while penalizing deviations from target speeds [13][14]. Group 5: Simulation and Real-World Testing - The framework was validated against real LiDAR data collected using the Unitree G1 robot, demonstrating high consistency in point cloud distribution and structural integrity between simulated and real data [21]. - The Omni-Perception tool showed significant advantages in rendering efficiency, maintaining linear growth in rendering time as the number of environments increased, unlike traditional methods which exhibited exponential growth [22]. - In various tests, the framework achieved a 100% success rate in static obstacle scenarios and demonstrated superior performance in dynamic environments compared to traditional methods [26][27].