A system includes: a location tracking subsystem in a facility containing support structures supporting items; a plurality of mobile computing devices associated with respective users; and a plurality of autonomous transporters to transport items transferred by users from the support structures, and/or transport items to the support structures for transfer thereto by users. User profiles contain, for each user, a physical activity metric and a physical activity target. The system includes a server to: obtain, from the location tracking subsystem, transporter and mobile device locations; obtain a task defining a task location, and an identifier of an item for transfer to or from a support structure at the task location; select a transporter, according to the task and transporter locations; select a mobile device, according to the task and mobile device locations, the physical activity metrics and targets; and allocate the task to the selected transporter and mobile device.

A controller continues to operate in a stable manner after program modification. A controller repeatedly executes a task A and a task B in cycles. The controller includes a RAM and a task control program. The RAM stores a fixed time set longer than an actual execution time of the task A as an execution time for the task A. The task control program executes the tasks A and B, and executes the task A by using the fixed time.

A controller continues to operate in a stable manner after program modification. A controller repeatedly executes a task A and a task B in cycles. The controller includes a RAM and a task control program. The RAM stores a fixed time set longer than an actual execution time of the task A as an execution time for the task A. The task control program executes the tasks A and B, and executes the task A by using the fixed time.