A multiple robot assembly cell for batch manufacturing is described and a new concept of an Activity Controller (AC) for such a cell is developed. The problem defined for the Activity Controller is which robot is to perform which operation, how, in terms of spatial routes and accessories, and when, in terms of timing and synchronization, in order to effectively achieve a certain task objective (e.g., minimize makespan time). The Activity Controller functions, structure, and algorithms for optimization and operational control are discussed, and then demonstrated on an actual assembly case.