Task execution quality significantly impacts multi-robot missions, yet existing task allocation frameworks rarely consider quality of service as a decision variable, despite its importance in applications like robotic disinfection and cleaning. We introduce the multi-robot, multi-objective, and multi-mode routing and scheduling (M3RS) problem, designed for time-constrained missions. In M3RS, each task offers multiple execution modes with varying resource needs, durations, and quality levels, allowing trade-offs across mission objectives. M3RS is modeled as a mixed-integer linear programming (MIP) problem and optimizes task sequencing and execution modes for each agent. We apply M3RS to multi-robot disinfection in healthcare and public spaces, optimizing disinfection quality and task completion rates. Through synthetic case studies, M3RS demonstrates 1.5%–45% performance improvements over the standard task allocation method across various metrics. Further, to improve compute time, we propose a clustering-based column generation algorithm that achieves solutions comparable to or better than the baseline MIP solver while reducing computation time by 60%. We also conduct case studies with simulated and real robots.

In this video, you see five robots working on a disinfection mission. Each target surface must be disinfected in a specified time-window with a specific service mode. Here, "modes" refer to the disinfection dosage provided by the robot. Mode 1 offers the highest disinfection quality but requires the most time and energy. Mode 3 provides the lowest quality with minimal time and energy consumption. Mode 2 serves as a balanced intermediate between Modes 1 and 3. The M3RS formulation is used to assign disinfection tasks and associated modes to different robots while adhering to user preference and mission constraints of time and capacity. M3RS uses two objectives quality of task execution vs quantity of tasks completed. The user preference for this disinfection mission prioritises quantity over quality of disinfection. over quantity. The schedules generated by M3RS choose lower disinfection quality modes in order to maximize the time available to complete as many jobs as possible. This simulation is conducted in Robot Operating System. (Note: no audio, Speed: 5X)