With Kiva serving as a catalyst, in the last 18 months there have been several new entrants into the goods-to-person mobile robot category for full case and split case picking, and for good reason.  There are many advantages to implementing this technology in your distribution center.

Advantages

Some of the advantages of mobile robots include:

• A scalable solution so you can add mobile robots and throughput as your business grows. This capability reduces your upfront capital expenditure.
• Redundancy with multiple robots which leads to greater reliability. If a mobile robot fails, it is simply removed and replaced with a spare. While the mobile robot is replaced, the system throughput might drop a little (10%), but your orders can still be processed (no downtime).
• Greater cube density allows more products to be stored for fulfillment.
• Higher throughput rates: 900 to 1000 lines per person hour.
• Full sequencing capability of “called on” product, meaning the shipping carton doesn't have to be routed to multiple pick locations. All of the products come to where the shipping carton or mixed pallet is being built, reducing a lot of conveyor and controls complexity for routing the orders.

Enabling Technologies

One of the enabling technologies for mobile robots has been ultracapacitors, which have historically been served by batteries. These ultracapacitors use nanotechnology to increase their energy density. Therefore, a much smaller ultracapacitor can power a mobile robot for a few more trips (cycles) than an equivalent-sized battery. The ultracapacitors recharge almost instantaneously on the fly and can withstand millions of charging cycles without significantly degrading their energy storage capacity.

Another enabling technology has been the bandwidth and amount of data that can flow on RF-based networks like ZigBee. These frequency hopping RF networks allow a swarm of mobile robots to communicate with each other easily for assignments and traffic control. A third enabling methodology has been the distribution of control intelligence from a central controller (like an air traffic controller) to each individual mobile robot. This method allows simpler parallel communications and more reliable processing.

New Options in Mobile Robotics

A couple of new entrant companies that have very impressive offerings include OPEX with its Perfect Pick™ product (each picking) and Symbotic with its MatrixSelect™ product (full case picking).

Perfect Pick™ deploys a scalable number of iBots (mobile robots) in each mini-load aisle. The iBots can each move both vertically and horizontally using rack and pinion type wheels that travel along both the rack beams and uprights. The throughput in each aisle is up to 1,000 line items (or inventory totes delivered) per man hour. This allows the picker to pick directly from the AS/RS aisle. Another benefit of this method includes the elimination of much of the shipping carton routing conveyor. 

Author: Bill Bastian II