Open-Source, Cost-Aware Kinematically Feasible Planning for Mobile and Surface Robotics

This paper introduces the Smac Planner, an openly available search-based planning framework with multiple algorithm implementations including 2D-A*, Hybrid-A*, and State Lattice planners. This work is motivated by the lack of performant and available feasible planners for mobile and surface robotics research. This paper contains three main contributions. First, it briefly describes a minimal open-source software framework where search-based planners may be easily added. Further, this paper characterizes new variations on the feasible planners - dubbed Cost-Aware - specific to mobile roboticist's needs. This fills the gap of missing kinematically feasible implementations suitable for academic, extension, and deployed use. Finally, we provide baseline benchmarking against other standard planning frameworks. Smac Planner has further significance by becoming the standard open-source planning system within ROS 2's Nav2 framework which powers thousands of robots in research and industry

Impact of ROS 2 Node Composition in Robotic Systems

The Robot Operating System 2 (ROS 2) is the second generation of ROS representing a step forward in the robotic framework. Several new types of nodes and executor models are integral to control where, how, and when information is processed in the computational graph. This paper explores and benchmarks one of these new node types -- the Component node -- which allows nodes to be composed manually or dynamically into processes while retaining separation of concerns in a codebase for distributed development. Composition is shown to achieve a high degree of performance optimization, particularly valuable for resource-constrained systems and sensor processing pipelines, enabling distributed tasks that would not be otherwise possible in ROS 2. In this work, we briefly introduce the significance and design of node composition, then our contribution of benchmarking is provided to analyze its impact on robotic systems. Its compelling influence on performance is shown through several experiments on the latest Long Term Support (LTS) ROS 2 distribution, Humble Hawksbill.Comment: IEEE Robotics and Automation Letters, 202

An open source tele-operation application for arbitrary N-DOF manipulators

Human operation and tele-operation of manipulators is required in a number of operation, validation, and experimental scenarios. An application, termed the Command Center, for commanding and receiving feedback from an arbitrary manipulator is presented to improve human-robot interaction. The Command Center dynamically updates available operations, feedback, command handling, and disabling automatically for any degree of freedom (DOF) manipulator utilizing MoveIt! for it’s path planning in the robotic operating system (ROS). The application is capable of joint and Cartesian space moves with variable speed control and MoveIt!’s builtin perception handling and obstacle avoidance. Features for gripper actuation are supported through the Command Center. No additional setup is required to operate under the existing ROS-Moveit! standard architecture. The application facilitates lowering the barrier to entry for robot interaction and provides ROS users with tightly integrated support for its current state of the art for a robot arm. Considerations for uses and comparisons of applications are explored.Ope

Training the union steward in alcoholism intervention

Includes bibliographical references (pages 64-66)This study, inspired by the apparent lack of attention given to training lay worker-agents in alcoholism intervention, outlines an investigation based upon a broad educational training approach for union stewards in the field of alcoholism prevention. The purpose of this study was to investigate changes that could be made in existing attitudes and levels of knowledge toward alcoholism in 130 union stewards and to provide a lay agent of health education to carry out primary, secondary and tertiary levels of prevention. Within each stratification of the problem, sex, age, type, work and type of industry in which employed, groups were chosen by random selection and assigned to one of four study groups. Questionnaires were devised which asked the steward what he knew about the identifiable signs and behavioral manifestations of alcoholism, and what he did when he knew of an alcoholic or other problem employee. The semantic differential scale was used to measure attitudes toward six types of problem employees. Behavior was measured by ten alternative action scales listing twelve action dimensions; six most likely and six least likely. The data were transferred from the evaluation tools to computer cards, and a program that performed frequency counts was used. A chi-square test was calculated to investigate the relationship between changes in action and attitude. A multiple regression analysis was applied to the data to determine the type of profile most likely to change during this study's case-seminar training program. Of the changes associated with the training program, the following six general statements apply. (1) Changes in attitudes and action from the training were statistically small. (2) In contrast, changes in attitudes and action from administration of the questionnaire alone were statistically pronounced. (3) The combination of testing and training procedures produced more changes than training alone. (4) There was a significant relationship between attitudes toward an alcoholic employee and attitudes toward other kinds of problem employees. (5) Negative evaluations by the stewards were directly correlated to more confrontation and referral behavior patterns. (6) Using the training approach of the problem employee, in general, yielded more favorable changes than the traditional training emphasis on the alcoholic alone

Ratio size and cocaine concentration effects on oral cocaine-reinforced behavior.

Monkeys were given a choice between cocaine solutions and water under concurrent fixed-ratio reinforcement schedules. The operant response was spout contact. Six rhesus monkeys served as subjects. The cocaine concentration was varied from 0.0125 to 0.8 mg/ml, and the fixed-ratio value was varied from 8 to 128. Cocaine maintained higher response rates than did water over a wide range of conditions. Response rate and number of cocaine deliveries per session were inverted U-shaped functions of concentration. These functions were shifted to the right as the fixed ratio was increased. The number of cocaine deliveries was more persistent as fixed-ratio value was increased when the unit dose was larger rather than smaller. Cocaine consumption was analyzed as a function of unit price (fixed-ratio value divided by cocaine concentration), and unit price accounted for between 77% and 92% of the variance in cocaine consumption for individual monkeys. The current data support the claim that a drug's reinforcing effects increase directly with dose and underscore the need to gather parametric data when examining the effects of experimental manipulations on a drug-reinforced baseline