Component-aware topology-guided task release and collision-free bimanual scheduling for cooperative disassembly of retired EV battery packs

Retired EV battery-pack disassembly requires robots to handle fastening dependencies, occlusion, tool compatibility, and inter-arm collisions in a compact workspace. This paper presents a component-aware framework that separates topology-guided task release, frontier-level operation selection, and fixed-path bimanual temporal coordination. A component-removal task is released only after its fasteners and blockers have been cleared and a tool-compatible single-arm path is feasible. Released operations are assigned to the screwdriver- or gripper-side arm, and the proposed priority rule selects the next operation from the current arm-specific executable frontier. For each selected path pair, an A ∗ search in path-index space coordinates left-arm, right-arm, or simultaneous advancement along fixed pre-generated single-arm paths, with node collision checks and time-synchronized sampled transition validation. The method was evaluated on a fixed electric-bus battery pack after manual safety preprocessing and top-cover removal. Across five complete robotic-stage trials per mode, S3 achieved a mean completion time of 1348 ± 53 s compared with 1955 ± 55 s for S0, corresponding to a 31.05% reduction and a reconstructed scheduling-level motion-overlap ratio of 44.51%. In a separate controlled 24-operation half-pack simulation, Proposed Priority reduced the makespan from 329.048 s with SPT to 317.273 s (3.58%) and increased the motion-overlap ratio from 4.48% to 8.33%, while the executable-frontier construction, arm assignment, pre-generated paths, A ∗ coordinator, collision model, and motion settings were held fixed. The results distinguish the effects of system-level task availability, frontier-level task selection, and fixed-path temporal coordination. Robustness to execution uncertainty and continuous collision freedom between finite collision-checking samples remain outside the demonstrated scope.