Operator Choice Modeling for Collaborative UAV Visual Search Tasks

Unmanned aerial vehicles (UAVs) provide unprecedented access to imagery of possible ground targets of interest in real time. The availability of this imagery is expected to increase with envisaged future missions of one operator controlling multiple UAVs. This research investigates decision models that can be used to develop assistive decision support for UAV operators involved in these complex search missions. Previous human-in-the-loop experiments have shown that operator detection probabilities may decay with increased search time. Providing the operators with the ability to requeue difficult images with the option of relooking at targets later was hypothesized to help operators improve their search accuracy. However, it was not well understood how mission performance could be impacted by operators performing requeues with multiple UAVs. This work extends a queuing model of the human operator by developing a retrial queue model (ReQM) that mathematically describes the use of relooks. We use ReQM to generate performance predictions through discrete event simulation. We validate these predictions through a human-in-the-loop experiment that evaluates the impact of requeuing on a simulated multiple-UAV mission. Our results suggest that, while requeuing can improve detection accuracy and decrease mean search times, operators may need additional decision support to use relooks effectively.Michigan/AFRL Collaborative Center in Control ScienceUnited States. Office of Naval Research (Grant N00014-07-1-0230

Reaching Consensus with Imprecise Probabilities over a Network

This paper discusses the problem of a distributed network of agents attempting to agree on an imprecise probability over a network. Unique from other related work however, the agents must reach agreement while accounting for relative uncertainties in their respective probabilities. First, we assume that the agents only seek to agree to a centralized estimate of the probabilities, without accounting for observed transitions. We provide two methods by which such an agreement can occur which uses ideas from Dirichlet distributions. The first methods interprets the consensus problem as an aggregation of Dirichlet distributions of the neighboring agents. The second method uses ideas from Kalman Consensus to approximate this consensus using the mean and the variance of the Dirichlet distributions. A key results of this paper is that we show that when the agents are simultaneously actively observing state transitions and attempting to reach consensus on the probabilities, the agreement protocol can be insensitive to any new information, and agreement is not possible. Ideas from exponential fading are adopted to improve convergence and reach a consistent agreement.This research was funded in part under Air Force Grants # F49620-01-1-0453 and # FA9550-08-1-0086

Teamwork in controlling multiple robots

Simultaneously controlling increasing numbers of robots requires multiple operators working together as a team. Helping operators allocate attention among different robots and determining how to construct the human-robot team to promote performance and reduce workload are critical questions that must be answered in these settings. To this end, we investigated the effect of team structure and search guidance on operators' performance, subjective workload, work processes and communication. To investigate team structure in an urban search and rescue setting, we compared a pooled condition, in which team members shared control of 24 robots, with a sector condition, in which each team member control half of all the robots. For search guidance, a notification was given when the operator spent too much time on one robot and either suggested or forced the operator to change to another robot. A total of 48 participants completed the experiment with two persons forming one team. The results demonstrate that automated search guidance neither increased nor decreased performance. However, suggested search guidance decreased average task completion time in Sector teams. Search guidance also influenced operators' teleoperation behaviors. For team structure, pooled teams experienced lower subjective workload than sector teams. Pooled teams communicated more than sector teams, but sector teams teleoperated more than pool teams.United States. Office of Naval ResearchUnited States. Air Force Office of Scientific Researc

Choice modeling of relook tasks for UAV search missions

This paper addresses human decision-making in supervisory control of a team of unmanned vehicles performing search missions. Previous work has proposed the use of a two-alternative choice framework, in which operators declare the presence or absence of a target in an image. It has been suggested that relooking at a target at some later time can help operators improve the accuracy of their decisions but it is not well understood how - or how well - operators handle this relook task with multiple UAVs. This paper makes two novel contributions in developing a choice model for a search task with relooks. First, we extend a previously proposed queueing model of the human operator by developing a retrial queue model that formally includes relooks. Since real models may deviate from some of the theoretical assumptions made in the requeueing literature, we develop a Discrete Event Simulation (DES) that embeds operator models derived from previous experimental data and present new results in the predicted performance of multi-UAV visual search tasks with relook. Our simulation results suggest that while relooks can in fact improve detection accuracy and decrease mean search times per target, the overall fraction found correctly is extremely sensitive to increased relooks

Interface Design for Unmanned Vehicle Supervision through Hybrid Cognitive Task Analysis

While there is currently significant interest in developing Unmanned Aerial Systems (UASs) that can be supervised by a single operator, the majority of these systems focus on Intelligence, Surveillance, and Reconnaissance (ISR) domains. One domain that has received significantly less attention is the use of multiple UASs to insert or extract supplies or people. To this end, MAVIES (Multi-Autonomous Vehicle Insertion-Extraction System) was developed to allow a single operator the ability to supervise a primary cargo Unmanned Aerial Vehicle (UAV) along with multiple scouting UAVs. This paper will detail the development of the design requirements generated through a Hybrid Cognitive Task Analysis (hCTA) and the display that resulted from these efforts. A major innovation in the hCTA process in this effort was the alteration of the traditional decision ladder process to specifically identify decision-making tasks that must be augmented with automation

Evaluating a Pattern-Based Visual Support Approach for Humanitarian Landmine Clearance

Unexploded landmines have severe post-conflict humanitarian repercussions: landmines cost lives, limbs and land. For deminers engaged in humanitarian landmine clearance, metal detectors remain the primary detection tool as more sophisticated technologies fail to get adopted due to restrictive cost, low reliability, and limited robustness. Metal detectors are, however, of limited effectiveness, as modern landmines contain only minimal amounts of metal, making them difficult to distinguish from the ubiquitous but harmless metallic clutter littering post-combat areas. We seek to improve the safety and efficiency of the demining process by developing support tools that will enable deminers to make better decisions using feedback from existing metal detectors. To this end, in this paper we propose and evaluate a novel, pattern-based visual support approach inspired by the documented strategies employed by expert deminers. In our laboratory study, participants provided with a prototype of our support tool were 80% less likely to mistake a mine for harmless clutter. A follow-up study demonstrates the potential of our pattern-based approach to enable peer decision-making support during landmine clearance. Lastly, we identify several design opportunities for further improving deminers' decision making capabilities.Engineering and Applied Science