Impacts of heterogeneous unmanned vehicle combinations on task performance and workload: A visual behavioral perspective

Heterogeneous unmanned vehicles system, comprising Unmanned Aerial Vehicles (UAVs) and Unmanned Ground Vehicles (UGVs), offer complementary advantages in Search and Rescue missions. However, the impact of different vehicle combinations on operator remains unclear. This study investigated how unmanned vehicle combinations (1UAV+3UGV, 2UAV+2UGV, and 3UAV+1UGV) influence operator performance and workload in Search and Rescue scenario. Thirty-six participants performed the simulated missions. The results indicate that the balanced 2UAV+2UGV combination leads to higher performance and lower workload. To identify underlying mechanisms, participants were grouped by median performance and workload. High-performance participants exhibited a more proactive and efficient information acquisition strategy, flexibly allocating attention through more frequent saccades and fixation transitions between critical areas. Additionally, higher perceived workload was associated with a video-centric attention pattern that may reflect visual tunneling and limit the acquisition of global mission information. This research integrates vehicle combination and cognitive mechanisms to inform the design of heterogeneous unmanned systems.