Perceived mental workload and operator performance of dexterous manipulators under time delay with master-slave interfaces

Robotic manipulators that use joystick interfaces for telemanipulation take time and effort to master and lack an intuitive basis for human robot interaction. These factors can hamper operator performance, increase cognitive workload, and limit overall user effectiveness on highly dexterous tasks. Master-slave interfaces (MSIs) used in the fields of animatronics, telesurgery, and hazardous materials handling are intuitive and improve operator performance, but are limited because they typically operate in a controlled environment and lack robustness. When Master Slave (MS) controllers use forcefeedback errors can accumulate and create instabilities due to the synchronous bilateral communication between the remote and local systems. Instability can be mitigated and errors reduced in these systems by separating the bilateral communication into a dual-unilateral (DU) asynchronous communication. This research focused on comparing and analyzing current MSI controllers with a new DU control method that reduces or eliminates MSI issues such as latency, error, and information loss while providing the user with accurate forcefeedback capability and transparency during operation. It used a simulation-based approach to determine which selected MSI controllers provide users with robust control of dexterous manipulators under time delay. Users performed a variety of dexterous force-feedback tasks with different controllers and the study measured objective task performance and completion time success along with cognitive workload related to user perceived task interaction and mental demands through subjective ratings on the NASA (National Aeronautics and Space Administration) Task Load Index (TLX). The research findings will help to develop MSI controllers designed to provide operators robust and intuitive interfaces for low-level control of dexterous manipulators.