煤矿狭窄非结构化巷道中履带式机器人动态避障方法

Dynamic obstacle avoidance method for tracked robot in narrow unstructured coal mine roadways

  • 摘要: 现有机器人避障多依赖单一传感器,在非结构化、动态障碍物随机出现的复杂巷道环境中,存在障碍物标定误差较大、避障安全裕度不足等问题。针对上述问题,面向煤矿狭窄非结构化巷道,提出了一种基于多传感器感知与深度强化学习的履带式机器人动态避障方法。利用可见光波段的高分辨率成像与红外波段的热辐射敏感特性,感知巷道中低照度和高反光环境;引入Mean Shift算法对巷道中障碍物出现概率进行核密度估计,标定障碍物三维空间坐标,解决巷道狭窄导致的视角局限与遮挡问题;利用球体包络法构建障碍物三维空间坐标对应的安全势场边界,作为深度强化学习避障奖励值的约束条件,根据避障奖励值优化机器人避障行为,完成动态避障。实验结果表明:在高粉尘浓度、强光及弱光条件下,该方法感知结果中可见光图像和红外图像的跨模态结构相似性均值均高于55%,能精准感知巷道环境;对障碍物位置的标定结果与实际位置的最大误差仅为0.4 m;应用该方法的机器人在行进过程中与障碍物之间的最小距离大于安全阈值,无碰撞事件发生,具有足够的避障安全裕度。

     

    Abstract: Existing robot obstacle avoidance methods mostly rely on a single sensor, which leads to large obstacle calibration errors and insufficient safety margins in complex unstructured roadway environments where dynamic obstacles appear randomly. To address these problems, a dynamic obstacle avoidance method for tracked robots based on multi-sensor perception and deep reinforcement learning was proposed for narrow unstructured coal mine roadways. The high-resolution imaging capability in the visible spectrum and the sensitivity to thermal radiation in the infrared band were used to perceive roadway environments with low illumination and high reflectivity. The Mean Shift algorithm was introduced to perform kernel density estimation on the occurrence probability of obstacles in the roadway, and the three-dimensional spatial coordinates of obstacles were calibrated to overcome the limited field of view and occlusion caused by the narrow roadways. The spherical envelope method was used to construct the safety potential field boundary corresponding to the three-dimensional spatial coordinates of obstacles as the constraint condition for the obstacle avoidance reward in deep reinforcement learning, and the robot obstacle avoidance behavior was optimized according to the reward to achieve dynamic obstacle avoidance. Experimental results showed that under conditions of high dust concentration, strong light, and weak light, the mean of cross-modal structural similarity between the visible light images and the infrared images of the perceived results was higher than 55%, enabling accurate perception of the roadway environment. The maximum error between the calibrated obstacle position and the actual position was only 0.4 m. During movement, the minimum distance between the robot using the proposed method and obstacles was greater than the safety threshold, and no collision occurred, indicating a sufficient safety margin for obstacle avoidance.

     

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