Dynamic Scheduling for Single-Arm Biomedical Analysis Robots: A Deterministic Real-Time Approach

Automated slide stainers usually protect incubation timing by running one technique at a time or processing slides in fixed batches, which leaves the robotic arm idle while samples incubate. This paper presents the dynamic scheduler of a slide-staining instrument with 42 heated reaction chambers served by a single arm. The scheduler ranks the ready tasks with fixed rules and admits a task only if its predicted execution and the incubations it starts do not collide with committed attendances; durations come from a kinematic model of the arm. In 19 runs on seven instruments, covering immunohistochemistry, immunofluorescence, and in situ hybridization, 4526 of 4528 incubations ended within their 60-s tolerance window, and the model predicted run makespans with a mean error of 1.26%. Simulations in a development environment showed that running heterogeneous protocols together took 28% to 66% less time than processing them in protocol batches, and that the required ranking rules gave a shorter makespan than four classical dispatching rules and a random order in 19 of 20 comparisons. At low load, a CP-SAT lower bound lies about 23% below the makespan, mainly because of deliberate holds that synchronize the preparation of reagent mixtures. Each decision took at most 55 ms.