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We introduce ProbLP, a probabilistic local planner, for safe navigation of an autonomous robot in dynamic, unknown, continuous, and cluttered environments. We combine the proposed reactive planner with an existing global planner and evaluate the hybrid in challenging simulated environments. The experiments show that our method achieves a 77% reduction in collisions over the straight-line local planner...
Follow the Gap Method (FGM) is a safety-focused geometric obstacle avoidance algorithm for local navigation. In this method, the largest gap around the robot is selected and the robot moves towards a goal point considering the largest gap and minimum distance to obstacle. One of the drawbacks of the method is the extension of the path which sometimes happens unnecessarily. Another drawback comes from...
A covering path generation algorithm is developed to generate a lengthwise pattern based on a polygon describing the outer boundary and obstacles (polygon holes) of a geographical area. The algorithm is applied to an autonomous lawn-care robot for application to large grass turfs, for example golf-courses, which require structured and precise cutting patterns. The geographical polygon is recorded...
This paper focus on the leader-follower control theory how to fits the Metro UTO (Unattended Train Operation) requirements. The core study of the paper concentrates on the practicability of the leader-follower control, which base on the ATO (Automatic Train Operation) and ATP (Automatic Train Protection) subsystems' monitoring and controlling in Metro. Firstly, the introduction of the paper's backgrounds...
Conventional path planning algorithms compute a single path through the configuration space. There is no guarantee that a physical robot will be able to track the trajectory while avoiding collisions, particularly in the presence of environmental perturbations and errors in the process model. Sequential composition combines planning and control by computing a sequence of controllers to execute rather...
We present a framework for online coordinated obstacle avoidance with formal safety guarantees. Such a formally verified trajectory planner can be used in shared human-robot workspaces to guarantee safety. The obstacle avoidance is based on estimation of the human occupancy on two different time scales. A long-term plan is created based on a probabilistic task representation, learned by demonstration,...
In this paper, we present a new robotic uterine positioner for total laparoscopic hysterectomy. The robot is designed to actively position the patient's uterus during surgery, a lengthy and tedious task that is traditionally performed by a human assistant. Safety is simply the most important concern when developing robots for surgical purposes; we address this concern in the design of our robot from...
This paper aims to reduce the number of occurrences of accidents during reinforcement learning(RL). RL is a powerful tool for autonomous acquisition of behavior without knowledge of dynamics of environment. However, because conventional algorithms require huge number of experiences of taking action to learn its goodness, the robots can not avoid having accidents during learning process. Such accidents...
A failsafe control strategy is presented for online safety certification of robot movements in a collaborative workspace with humans. This approach plans, predicts and uses formal guarantees on reachable sets of a robot arm and a human obstacle to verify the safety and feasibility of a trajectory in real time. The robots considered are serial link robots under Computed Torque schemes of control. We...
We consider the problem of coordinating a collection of robots at an intersection area taking into account dynamical constraints due to actuator limitations. We adopt the coordination space approach, which is standard in multiple robot motion planning. Assuming the priorities between robots are assigned in advance and the existence of a collision-free trajectory respecting those priorities, we propose...
This paper treats the safety issues in coordinated transportation of an object via multiple Unmanned Aerial Vehicles with Manipulator Systems (UAVMS); in particular, the case of obstacle avoidance is considered. The proposed paradigm is based on the so-called Null-Space-based Behavioral (NSB) control approach, that allows to achieve multiple tasks simultaneously. Two different scenarios of bar transportation...
The vision-based mechanisms that pedestrians in social groups use to navigate in dynamic environments, avoiding obstacles and each others, have been subject to a large amount of research in social anthropology and biological sciences. We build on recent results in these fields to develop a novel fully-distributed algorithm for robot local navigation, which implements the same heuristics for mutual...
The area of robotic surgical systems has to deal with several important safety aspects to ensure that the patient and the Operating Room staff are safe. A robotic surgical system has to fulfill specific safety requirements and to ensure that the system reacts like its specification. To this end, a verification process is necessary. In this paper an architecture for robotic surgery is modeled using...
This research develops a new graph-map method for autonomous car-like mobile robots based on variable-resolution division of space. Unlike conventional roadmaps, which include position information only, the proposed graph-map also includes orientation information of the car-like robot. In this manner, the robot is able to plan a path in detail. The orientation information of each node is not a fixed...
This paper addresses the problem of navigating a mobile robot with a limited field-of-view in a unknown dynamic environment. In such a situation, absolute motion safety, i.e. such that no collision will ever take place whatever happens, is impossible to guarantee. It is therefore settled for a weaker level of motion safety dubbed passive motion safety: it guarantees that, if a collision takes place,...
For reasoning about the safety of a robot system, it is sufficient to pretend the robot to reach an Inevitable Collision Sate (ICS). Otherwise, there exists no future trajectory which can avoid a collision. The usage of ICS is limited due to its computational complexity. One reason for this is, that the ICS computation cannot be done separately for each obstacle. Hence, ICS needs to be recomputed...
When collaboration between human users and robots involves physical interaction, the importance of the safety issue arises. We propose a method to transfer to robots several tasks demonstrated by the user through kinesthetic teaching and subsequently learned using a weighted combination of dynamical systems (DS). The approach used to encode the desired skills ensures a safe robot behavior during the...
In this paper we consider the problem of ensuring that a multi-agent robot control system is both safe and effective in the presence of learning components. Safety, i.e., proving that a potentially dangerous configuration is never reached in the control system, usually competes with effectiveness, i.e., ensuring that tasks are performed at an acceptable level of quality. In particular, we focus on...
This paper presents an innovative 3D analytical algorithm for the resolution of the pair-wise non-cooperative collision avoidance problem between aircrafts. The proposed algorithm addresses the above described problem by using an innovative approach, based on the consideration of a cylindrical safety bubble, and it is able to obtain an optimal three-dimensional analytical solution for this problem...
This paper presents a new on-line planner for dynamic environments that is based on the concept of velocity obstacles (VO). It addresses the issue of motion safety, i.e. avoiding states of inevitable collision, by selecting a proper time horizon for the velocity obstacle. The proper choice of the time horizon ensures that the boundary of the velocity obstacle coincides with the boundary of the set...
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