Collaborative robots, often called cobots, are designed to work near people in shared warehouse spaces such as packing stations, sorting areas, and order fulfillment lines. They matter because modern warehouses must move thousands of items quickly while reducing worker fatigue, errors, and travel distance. A cobot arm can lift, scan, sort, or place objects while a human handles tasks that require judgment and flexibility.
Autonomous mobile robots can carry bins between storage racks and workstations, turning the warehouse into a coordinated flow system.
Key Facts
- Throughput = items processed / time, such as 600 packages / 2 h = 300 packages per hour.
- Average speed = distance / time, so v = d / t for a mobile robot traveling between warehouse zones.
- Cycle time is the time for one complete task, and lower cycle time usually increases throughput.
- Payload is the maximum mass a robot can safely carry or lift, often measured in kilograms.
- Work = force × distance, W = Fd, useful for estimating the mechanical effort of lifting or pushing items.
- Safety sensors reduce robot speed or stop motion when a person enters a protected zone.
Vocabulary
- Collaborative robot
- A collaborative robot is a robot designed to work safely near humans by using force limits, sensors, and controlled motion.
- Autonomous mobile robot
- An autonomous mobile robot is a wheeled robot that navigates through a warehouse without fixed tracks by using maps, sensors, and control software.
- Throughput
- Throughput is the number of items, orders, or packages completed in a given amount of time.
- Cycle time
- Cycle time is the time required to complete one repeated operation, such as picking one item and placing it in a box.
- Payload
- Payload is the maximum load a robot can safely carry, lift, or manipulate during normal operation.
Common Mistakes to Avoid
- Confusing speed with throughput, because a faster robot does not always process more orders if loading, scanning, or human handoff creates a bottleneck.
- Ignoring payload limits, because lifting a box above the rated mass can reduce accuracy, damage the robot, or create an unsafe condition.
- Assuming cobots need no safety planning, because collaborative operation still requires risk assessment, safe zones, speed limits, and emergency stops.
- Counting only robot travel time, because real warehouse performance also includes waiting time, picking time, scanning time, and packing time.
Practice Questions
- 1 An autonomous mobile robot travels 180 m from storage racks to a packing station in 3 minutes. What is its average speed in m/s?
- 2 A cobot packs 24 boxes in 6 minutes while working at a constant rate. What is its throughput in boxes per hour, and what is its cycle time per box?
- 3 A warehouse adds a fast mobile robot, but order output does not increase. Explain how a bottleneck at the scanner, packing station, or human handoff could limit the total system throughput.