Adaptive planning for distributed systems using goal accomplishment tracking

Goal accomplishment tracking is the process of monitoring the progress of a task or series of tasks towards completing a goal. Goal accomplishment tracking is used to monitor goal progress in a variety of domains, including workflow processing, teleoperation and industrial manufacturing. Practically, it involves the constant monitoring of task execution, analysis of this data to determine the task progress and notification of interested parties. This information is usually used in a passive way to observe goal progress. However, responding to this information may prevent goal failures. In addition, responding proactively in an opportunistic way can also lead to goals being completed faster. This paper proposes an architecture to support the adaptive planning of tasks for fault tolerance or opportunistic task execution based on goal accomplishment tracking. It argues that dramatically increased performance can be gained by monitoring task execution and altering plans dynamically

Shortest Path Planning Algorithm – A Particle Swarm Optimization (PSO) Approach

Path planning for a mobile robot is a difficult task and has been widely studied in robotics. The objective of recent researches is not just to find feasible paths but to find paths that are optimal with respect to distance covered and safety of the robot. Techniques based on optimization have been proposed to solve this problem but some of them used techniques that may converge to local minimum. In this paper, we present a global path planning algorithm for a mobile robot in a known environment with static obstacles. This algorithm finds the optimal path with respect to distance covered. It uses particle swarm optimization (PSO) technique for convergence to global minimum and a customized algorithm which generates the coordinates of the search space. Our customized algorithm generates the coordinates of the search space and passes the result to the PSO algorithm which then uses the coordinate values to determine the optimal path from start to finish. We perform our experiments using four different environments with population size 100 each in a 10 x 10 grid terrain and our results are favorable

Implementation of distributed partitioning algorithms using mobile Wheelphones

This thesis presents the implementation process of partitioning algorithms from the theorical ideas to sperimental result

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 320)

This bibliography lists 125 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during January, 1989. Subject coverage includes: aerospace medicine and psychology, life support systems and controlled environments, safety equipment, exobiology and extraterrestrial life, and flight crew behavior and performance

Evaluation studies of robotic rollators by the user perspective: A systematic review

Background: Robotic rollators enhance the basic functions of established devices by technically advanced physical, cognitive, or sensory support to increase autonomy in persons with severe impairment. In the evaluation of such Ambient Assisted Living solutions, both the technical and user perspectives are important to prove usability, effectiveness, and safety, and to ensure adequate device application.Objective: The aim of this systematic review is to summarize the methodology of studies evaluating robotic rollators with focus on the user perspective and to give recommendations for future evaluation studies.Methods: A systematic literature search up to December 31, 2014 was conducted based on the Cochrane Review methodology using the electronic databases PubMed and IEEE Xplore. Articles were selected according to the following inclusion criteria: Evaluation studies of robotic rollators documenting human-robot interaction, no case reports, published in English language.Results: Twenty-eight studies were identified that met the predefined inclusion criteria. Large heterogeneity in the definitions of the target user group, study populations, study designs, and assessment methods was found across the included studies. No generic methodology to evaluate robotic rollators could be identified. We found major methodological shortcomings related to insufficient sample descriptions and sample sizes, and lack of appropriate, standardized and validated assessment methods. Long-term use in habitual environment was also not evaluated.Conclusions: Apart from the heterogeneity, methodological deficits in most of the identified studies became apparent. Recommendations for future evaluation studies include: clear definition of target user group, adequate selection of subjects, inclusion of other assistive mobility devices for comparison, evaluation of the habitual use of advanced prototypes, adequate assessment strategy with established, standardized and validated methods, and statistical analysis of study results. Assessment strategies may additionally focus on specific functionalities of the robotic rollators allowing an individually tailored assessment of innovative features to document their added value

Improved Exploration with Stochastic Policies in Deep Reinforcement Learning

Deep reinforcement learning has recently shown promising results in robot control, but even current state-of-the-art algorithms fail in solving seemingly simple realistic tasks. For example, OpenAI et al. 2019 demonstrate the learning of dexterous in-hand manipulation of objects lying on the palm of an upside oriented robot hand. However, manipulating an object from above (i.e., the hand is oriented upside-down) turns out to be fundamentally more difficult to learn for current algorithms because the object has to be robustly grasped at all times to avoid immediate failure. In this thesis, we identify the commonly used naive exploration strategies as the main issue. Therefore, we propose to utilize more expressive stochastic policy distributions to enable reinforcement learning agents to learn to explore in a targeted manner. In particular, we extend the Soft Actor-Critic algorithm with policy distributions of varying expressiveness. We analyze how these variants explore in simplified environments with adjustable difficulties that we designed specifically to mimic the core problem of dexterous in-hand manipulation. We find that stochastic policies with expressive distributions can learn fundamentally more complex tasks. Moreover, beyond the exploration behavior, we show that in not perfectly observable environments, agents that represent their final (learned) policy with expressive distributions can solve tasks where commonly used simpler distributions fail

Condition Monitoring of a Belt-Based Transmission System for Comau Racer3 Robots

This project has been developed in collaboration with Comau Robotics S.p.a and the main goal is the development in China of an Health Monitoring Pro-cess using vibration analysis. This project is connected to the activity of Cost Reduction carried out by the PD Cost Engineering Department in China. The Project is divided in two part: 1. Data Acquisition 2. Data Analysis An Automatic Acquisition of the moni.log file is carried out and is discussed in Chapter 1. As for the Data Analysis is concerned a data driven approach is considered and developed in frequency domain through the FFT transform and in time domain using the Wavelet transform. In Chapter 2 a list of the techiques used nowadays for the Signal Analysis and the Vibration Monitoring is shown in time domain, frequency domain and time-frequency domain. In Chapter 3 the state of art of the Condition Monitoring of all the possible ma-chinery part is carried out from the evaluation of the spectrum of the current and speed. In Chapter 4 are evaluated disturbances that are not related to a fault but be-long to a normal behaviour of the system acting on the measured forces. Motor Torque Ripple and Output Noise Resolution are disturbance dependent on ve-locity and are mentioned in comparison to the one related to the configuration of the Robot. In Chapter 5 a particular study case is assigned: the noise problem due to belt-based power transmission system of the axis three of a Racer 3 Robot in Endu-rance test. The chapter presents the test plan done including all the simula-tions. In Chapter 6 all the results are shown demostrating how the vibration analysis carried out from an external sensor can be confirmed looking at the spectral content of the speed and the current. In the last Chapter the final conclusions and a possible development of this thesis are presented considering both a a Model of Signal and a Model Based approach