In the context of predicting pedestrian trajectories for indoor mobile robots, it is crucial to accurately measure the distance between indoor pedestrians and robots. This study aims to address this requirement by extracting pedestrians as regions of interest and mitigating issues related to inaccurate depth camera distance measurements and illumination conditions. To tackle these challenges, we focus on an improved version of the H-GrabCut image segmentation algorithm, which involves four steps for segmenting indoor pedestrians. Firstly, we leverage the YOLO-V5 object recognition algorithm to construct detection nodes. Next, we propose an enhanced BIL-MSRCR algorithm to enhance the edge details of pedestrians. Finally, we optimize the clustering features of the GrabCut algorithm by incorporating two-dimensional entropy, UV component distance, and LBP texture feature values. The experimental results demonstrate that our algorithm achieves a segmentation accuracy of 97.13% in both the INRIA dataset and real-world tests, outperforming alternative methods in terms of sensitivity, missegmentation rate, and intersection-over-union metrics. These experiments confirm the feasibility and practicality of our approach. The aforementioned findings will be utilized in the preliminary processing of indoor mobile robot pedestrian trajectory prediction and enable path planning based on the predicted results.
Lung cancer is the leading cause of cancer deaths worldwide. Although several lung cancer diagnostic methods are available for lung nodule biopsy, there are limitations in terms of accuracy, safety, and invasiveness. Transbronchial needle aspiration (TBNA) is a common method for diagnosing and treating lung cancer that involves a robot-assisted medical flexible needle moving along a curved three-dimensional trajectory, avoiding anatomical barriers to achieve clinically meaningful goals in humans. Inspired by the puncture angle between the needle tip and the vessel in venipuncture, we suggest that different orientations of the medical flexible needle puncture path affect the cost of the puncture trajectory and propose an effective puncture region based on the optimal puncture direction, which is a strategy based on imposing geometric constraints on the search space of the puncture direction, and based on this, we focused on the improved implementation of RCS*. Planning within the TBNA-based lung environment was performed using the rapidly exploring random tree (RRT), resolution-complete search (RCS), and RCS* (a resolution-optimal version of RCS) within an effective puncture region. The experimental results show that the optimal puncture direction corresponding to the lowest cost puncture trajectory is consistent among the three algorithms and RCS* is more efficient for planning. The experiments verified the feasibility and practicality of our proposed minimum puncture angle and puncture effective region and facilitated the study of the puncture direction of flexible needle puncture.
Percutaneous puncture has become one of the most widely used minimally invasive techniques in clinical practice due to its advantages of low trauma, quick recovery and easy operation. However, incomplete needle tip movement, tissue barriers and complex distribution of sensitive organs make it difficult to balance puncture accuracy and safety. To this end, this paper proposes a new puncture path planning algorithm for flexible needles, which integrates gravitational guidance, bi-directional adaptive expansion, optimal node selection based on the A* algorithm, and path optimization strategies, with Bi-Rapid-Research Random Trees (Bi-RRTs) at its core, to significantly improve obstacle avoidance capability and computational efficiency. The simulation results of 2D and 3D complex scenes in MATLAB show that compared with the traditional RRT algorithm and Bi-RRT algorithm, the GBOPBi-RRT algorithm achieves significant advantages in terms of path length, computation time and node size. In particular, in the 3D environment, the GBOPBi-RRT algorithm shortens the planning path by 43.21% compared with RRT, 27.47% compared with RRT* and 30.33% compared with Bi-RRT, which provides a reliable solution for efficient planning of percutaneous puncture with flexible needles.
Legged robots are particularly well-suited for navigating terrains that are inaccessible to wheeled robots, which has led to a significant increase in their applications in recent years. However, many existing control approaches still struggle to achieve generalization in diverse and unstructured environments. In this work, we introduce the MSD training framework for general and agile locomotion of legged robots through a multi-skill distillation approach. First, expert policies are trained for different terrains. Then, using the DAgger algorithm, these expert skills are distilled into a single deployable policy. The proposed policy integrates depth images as exteroceptive observations, enabling agile navigation across diverse and unstructured terrains. Finally, deployment on the MagicDog-W robot validates the policy’s capability to achieve robust and flexible locomotion in challenging environments.