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Path planning is a very important step for mobile smart vehicles in complex environments. Sampling based planners such as the Probabilistic Roadmap Method (PRM) have been widely used for smart vehicle applications. However, there exist some shortcomings, such as low efficiency, low reuse rate of the roadmap, and a lack of guidance in the selection of sampling points. To solve the above problems, we designed a pseudo-random sampling strategy with the main spatial axis as the reference axis. We optimized the generation of sampling points, removed redundant sampling points, set the distance threshold between road points, adopted a two-way incremental method for collision detections, and optimized the number of collision detection calls to improve the construction efficiency of the roadmap. The key road points of the planned path were extracted as discrete control points of the Bessel curve, and the paths were smoothed to make the generated paths more consistent with the driving conditions of vehicles. The correctness of the modified PRM was verified and analyzed using MATLAB and ROS to build a test platform. Compared with the basic PRM algorithm, the modified PRM algorithm has advantages related to speed in constructing the roadmap, path planning, and path length.

Various navigation tasks involving dynamic scenarios require mobile robots to meet the requirements of a high planning success rate, fast planning, dynamic obstacle avoidance, and shortest path. PRM (probabilistic roadmap method), as one of the classical path planning methods, is characterized by simple principles, probabilistic completeness, fast planning speed, and the formation of asymptotically optimal paths, but has poor performance in dynamic obstacle avoidance. In this study, we use the idea of hierarchical planning to improve the dynamic obstacle avoidance performance of PRM by introducing D* into the network construction and planning process of PRM. To demonstrate the feasibility of the proposed method, we conducted simulation experiments using the proposed PRM-D* (probabilistic roadmap method and D*) method for maps of different complexity and compared the results with those obtained by classical methods such as SPARS2 (improving sparse roadmap spanners). The experiments demonstrate that our method is non-optimal in terms of path length but second only to graph search methods; it outperforms other methods in static planning, with an average planning time of less than 1 s, and in terms of the dynamic planning speed, our method is two orders of magnitude faster than the SPARS2 method, with a single dynamic planning time of less than 0.02 s. Finally, we deployed the proposed PRM-D* algorithm on a real vehicle for experimental validation. The experimental results show that the proposed method was able to perform the navigation task in a real-world scenario.

In recent years, enormous advancement has taken place in biomedical engineering, which has paved the way for robot-assisted surgery in various complex surgical procedures. In robotic surgery, the reinforcement-based Temporal Difference (TD) based approach through assistive approaches has tremendous potential. Probabilistic Roadmap (PR) can be used for recognition of the path to the region of interest without any obstacles and, Inverse Kinematics (IK) approach can be used for the accurate approximation of the pixel space to the real-time workspace. Our proposed system would be more effective in approximating the path length, depth evaluation, and less invasive contact force sensor. This article presents a robust algorithm that would assist in robotic surgery for censorious surgeries in real-time. For working on such soft tissues, software-driven procedures and algorithms must be more precise in choosing the optimal path for reaching out to the procedural region. The statistical analysis has proven that the proposed approach would be outperforming under favorable learning rate, discount factor, and the exploration factor.

Global path planning using roadmap (RM) path-planning methods including Voronoi diagram (VD), rapidly exploring random trees (RRT), and probabilistic roadmap (PRM) has gained popularity over the years in robotics. These global path-planning methods are usually combined with other path-planning techniques to achieve collision-free robot control to a specified destination. However, it is unclear which of these methods is the best choice to compute the efficient path in terms of path length, computation time, path safety, and consistency of path computation. This article reviewed and adopted a comparative research methodology to perform a comparative analysis to determine the efficiency of these methods in terms of path optimality, safety, consistency, and computation time. A hundred maps of different complexities with obstacle occupancy rates ranging from 50.95% to 78.42% were used to evaluate the performance of the RM path-planning methods. Each method demonstrated unique strengths and limitations. The study provides critical insights into their relative performance, highlighting application-specific recommendations for selecting the most suitable RM method. These findings contribute to advancing robot path-planning techniques by offering a detailed evaluation of widely adopted methods.

In unmanned aerial vehicle (UAV)-aided wireless sensor networks (UWSNs), a UAV is employed as a mobile sink to gather data from sensor nodes. Incorporating UAV helps prolong the network lifetime and avoid the energy-hole problem faced by sensor networks. In emergency applications, timely data collection from sensor nodes and transferal of the data to the base station (BS) is a prime requisite. The timely and safe path of UAV is one of the fundamental premises for effective UWSN operations. It is essential and challenging to identify a suitable path in an environment comprising various obstacles and to ensure that the path can efficiently reach the target point. This paper proposes a hybrid path planning (HPP) algorithm for efficient data collection by assuring the shortest collision-free path for UAV in emergency environments. In the proposed HPP scheme, the probabilistic roadmap (PRM) algorithm is used to design the shortest trajectory map and the optimized artificial bee colony (ABC) algorithm to improve different path constraints in a three-dimensional environment. Our simulation results show that the proposed HPP outperforms the PRM and conventional ABC schemes significantly in terms of flight time, energy consumption, convergence time, and flight path.

The development in Multi-Robot Systems (MRS) has become one of the most exploited fields of research in robotics in recent years. This is due to the robustness and versatility they present to effectively undertake a set of tasks autonomously. One of the essential elements for several vehicles, in this case, Unmanned Aerial Vehicles (UAVs), to perform tasks autonomously and cooperatively is trajectory planning, which is necessary to guarantee the safe and collision-free movement of the different vehicles. This document includes the planning of multiple trajectories for a swarm of UAVs based on 3D Probabilistic Roadmaps (PRM). This swarm is capable of reaching different locations of interest in different cases (labeled and unlabeled), supporting of an Emergency Response Team (ERT) in emergencies in urban environments. In addition, an architecture based on Robot Operating System (ROS) is presented to allow the simulation and integration of the methods developed in a UAV swarm. This architecture allows the communications with the MavLink protocol and control via the Pixhawk autopilot, for a quick and easy implementation in real UAVs. The proposed method was validated by experiments simulating building emergences. Finally, the obtained results show that methods based on probability roadmaps create effective solutions in terms of calculation time in the case of scalable systems in different situations along with their integration into a versatile framework such as ROS.

Autonomous exploration in unknown environments is a fundamental problem for the practical application of unmanned ground vehicles (UGVs). However, existing exploration methods face difficulties when directly applied to UGVs due to limited sensory coverage, conservative exploration strategies, inappropriate decision frequencies, and the non-holonomic constraints of wheeled vehicles. In this paper, we present IB-PRM, a hierarchical planning method that combines Incremental B-splines with a probabilistic roadmap, which can support rapid exploration by a UGV in complex unknown environments. We define a new frontier structure that includes both information-gain guidance and a B-spline curve segment with different arrival orientations to satisfy the non-holonomic constraint characteristics of UGVs. We construct and maintain local and global graphs to generate and store filtered frontiers. By jointly solving the Traveling Salesman Problem (TSP) using these frontiers, we obtain the optimal global path traversing feasible frontiers. Finally, we optimize the global path based on the Time Elastic Band (TEB) algorithm to obtain a smooth, continuous, and feasible local trajectory. We conducted comparative experiments with existing advanced exploration methods in simulation environments of different scenarios, and the experimental results demonstrate that our method can effectively improve the efficiency of UGV exploration.

Optimum path planning is a fundamental necessity for the successful functioning of a mobile robot in industrial applications. This research work investigates the application of the artificial bee colony (ABC) approach, probabilistic roadmap (PRM) method, and evolutionary programming (EP) algorithm to tackle the issue of single and multi-robot path planning in partially known or unknown industrial complex environments. Conventional techniques depend on external factors such as delay of information from one bee's stage to another for selecting neighbour food points. Due to this, its efficiency is comparatively low and might result in longer runtimes. To address these challenges, a novel hybrid framework based on ABC-PRM-EP has been introduced. Firstly, a suboptimal initial feasible path is attained by a new framework (ABC-PRM) within the mobile robot sensor detection range. Then, EP performs refinement of that attained suboptimal path to provide a short and optimum path. Also, a multi-robot collaboration strategy has been introduced based on the concept of hold-up. A number of comparative studies have been conducted in three different test scenarios with different complexity to validate the proposed framework efficiency and performance. Different performance indices such as path length (m), smoothness (rad), collision safety value, success rate, processing time (s), and convergence speed have been measured to validate the effectiveness of the proposed framework. The comparative analysis obtained from these test scenarios indicates that the proposed framework outperforms conventional ABC, ABC-EP and HPSO-GWO-EA, while performing path planning.

In order to enhance performance of robot systems in the manufacturing industry, it is essential to develop motion and task planning algorithms. Especially, it is important for the motion plan to be generated automatically in order to deal with various working environments. Although PRM (Probabilistic Roadmap) provides feasible paths when the starting and goal positions of a robot manipulator are given, the path might not be smooth enough, which can lead to inefficient performance of the robot system. This paper proposes a motion planning algorithm for robot manipulators using a twin delayed deep deterministic policy gradient (TD3) which is a reinforcement learning algorithm tailored to MDP with continuous action. Besides, hindsight experience replay (HER) is employed in the TD3 to enhance sample efficiency. Since path planning for a robot manipulator is an MDP (Markov Decision Process) with sparse reward and HER can deal with such a problem, this paper proposes a motion planning algorithm using TD3 with HER. The proposed algorithm is applied to 2-DOF and 3-DOF manipulators and it is shown that the designed paths are smoother and shorter than those designed by PRM.

An indispensable feature of a modern intelligent robot is its capability to plan short and safe motions in the presence of obstacles in its workspace, which is highly important for industrial manipulators in charge of automatic picking and placing, welding, painting, etc. On the other hand, collision-free motion planning of serial manipulators becomes exponentially hard with the increase of number of joints, and so efficient methods like sampling-based ones are vastly used for most real-world problems. In this paper, we propose a new variation of sampling-based methods called semi-lazy probabilistic roadmap (SLPRM) for motion planning of industrial manipulators, which benefits from the advantages of the basic probabilistic roadmap (PRM) and lazy-PRM (LPRM) methods. Unlike the exhaustive and zero collision-checking policies implemented respectively in PRM and LPRM, the SLPRM collision-checks random configurations for only m terminal links (i.e., from end-effector backwards) of the manipulator in the roadmap construction phase. As a result, on one hand, the roadmap construction time reduces compared with PRM due to less collision checks, and on the other hand, query times decrease compared with LPRM due to a better quality of the initial roadmap. A central decision in SLPRM is to properly determine the value of m , which has a direct effect on its speed. For this purpose, a new parameter tuning approach based on a combination of Shannon’s Entropy and VIKOR methods is implemented to determine the best values for m and all other parameters of the algorithm. The proposed method has been tested and implemented in simulated and real workspace scenarios for an RV-E3J Mitsubishi industrial manipulator robot, and the results showed that the mean planning time of the SLPRM was shorter compared with that of the PRM and LPRM. To make the algorithm resilient and robust to internal faults and environmental variations such as positional errors, joint failures, and obstacle displacements, we have also proposed the resilient and robust SLPRM, which through concentrated sampling and roadmap-amending procedures, can handle unexpected failures and changes.