(VDW) refers to the use of the voice direction and speech recognition software in warehouses and distribution centers. VDW has been in use since the late 1990s, and its use is expected to increase rapidly over the next five years due to advances in technology and decreasing costs for the voice directed software and for the mobile computers on which it runs.
In a voice directed warehouse, workers wear a headset connected to a small wearable computer, similar in size to a Sony Walkman
Walkman is a Sony brand tradename originally used for portable audio cassette, and now used to market Sony's portable audio and video players as well as a line of Sony Ericsson mobile phones...
, which tells the worker where to go and what to do using verbal prompts. Workers confirm their tasks by speaking pre-defined commands and reading confirmation codes printed on locations or products throughout the warehouse. The speech recognition software running on the wearable computer 'understands' the workers' responses .
Voice-directed warehousing is typically used instead of paper- or mobile computer-based systems that require workers to read instructions and scan barcodes or key-enter information to confirm their tasks. By freeing a worker's hands and eyes, voice directed systems typically improve efficiency, accuracy, and safety . Whilst VDW was originally used in picking orders, now all warehouse functions such as goods receiving, put-away, replenishment, shipping, and returns processing can be coordinated by voice systems.
The first incarnations of voice directed warehousing
were implemented in distribution centers in the early 1990s. Since then, voice has changed dramatically. Most notably, the technology was originally limited to picking, whereas now all warehouse functions (picking, receiving/put-away, replenishment, shipping) can be coordinated by voice systems. As these processes move from being paper-centric, to RF-centric (barcode scanning) and now voice-centric. For some, voice has become the starting point for re-engineering warehouse processes and systems, rather than an after-thought.
VDW technology has also undergone an evolution as more competitors have entered the market. The first solutions, introduced by Vocollect
and were based on dedicated and rugged voice appliances, mobile computing devices that ran the speech recognition software and that communicated with a server over a wireless network. These special purpose voice appliances use a proprietary speech recognition engine that was specially designed for the warehouse and provided by the appliance manufacturer. Since the early 2000s, more voice suppliers have entered the market, providing voice recognition systems for standard mobile computing devices that had been used previously for barcode scanning applications in the warehouse. These standard mobile computers from companies like Motorola Solutions
and LXE also support non-proprietary recognition software. The uncoupling of the hardware and speech recognition software has resulted in a lower priced voice-directed warehousing solutions and an increase in the number of software providers. These two factors contributed to a rapid rise in adoption of VDW that continues today.
Implementing voice systems in the warehouse has among its benefits
- Increased picking accuracy
- Increased inventory accuracy
- Increased employee productivity
- Improved safety
- Reduced new worker training time
- Increases job satisfaction for warehouse associates
- Eliminates cost of printing and distributing picking documents
- Growing customer satisfaction
One of the great productivity benefits of voice-based systems is that they allow operators to do two things at once where as other media used in warehouses such as paper or radio frequency terminals tend to require that you surrender the use of at least one hand or you have to stop and read something before proceeding. This productivity benefit tends to be inversely related to the fraction of an operator's day spent walking.
How it works
Each operator is given a voice-enabled mobile computer. These devices need not have screens or keypads – operators communicate with the system via headset.
Managers use a warehouse management system
A warehouse management system, or WMS, is a key part of the supply chain and primarily aims to control the movement and storage of materials within a warehouse and process the associated transactions, including shipping, receiving, putaway and picking...
(WMS) or management software provided as part of a voice directed warehouse application system to assign work to operators – jobs such as picking, put-away, replenishment, and truck loading. How this assignment process takes place is largely implementation specific. For example, operators might be assigned to pick specific orders or load specific trucks – or they might simply be assigned to picking, and be automatically placed on the highest-priority job.
With voice picking, the voice system directs the operator to perform each pick, giving them directions to the pick location. Depending on system configuration, the operator may be prompted for a location check-digit or a container check-digit as well as a count-back. Following is an example picking dialog:
|| Go to building one.
|| Aisle five.
|| Bay twenty-seven.
|| Pick four cases of double-chocolate almond fudge.
|| What are the check-digits?
|| These might be from the pallet license or location
|| How much remains?
|| Optional count-back – increases accuracy and reduces speed
…and so on, until the order is complete. The system then directs them to the location to put their pallet (onto a truck, into a staging area) and then tells them to take a new pallet and start the next pick. Unique license plates can be assigned to each picked pallet so that they can be easily located in the warehouse – and so that the voice system can direct the process of loading staged pallets onto trucks.
In voice directed put-away, the system asks the operator for the license(s) that they will be putting away. The system then directs the operator to put away each license, requesting a location check-digit from the put-away location.
Some systems can also take advantage of quicker multi-pallet walkies by performing two-phase putaway. Walkie operators are directed to take received pallets to the appropriate aisle where reach operators pick them up and complete the operation.
In voice directed replenishment, the system directs the operator to pick up a particular skid from a particular location, and then directs them to the appropriate picking location.
The WMS coordinates which pallets are scheduled for replenishment, and where they are to be put – a sophisticated WMS may assign SKUs to pickfaces dynamically according to SKU velocity, available space, proximity to door, etc.
Perpetual inventory checking can be built in to either the picking task or the replenishment task, improving the efficiency and accuracy of the inventory checking process.
With voice directed truck loading, the voice system directs the operator to each picked pallet
A pallet , sometimes called a skid, is a flat transport structure that supports goods in a stable fashion while being lifted by a forklift, pallet jack, front loader or other jacking device. A pallet is the structural foundation of a unit load which allows handling and storage efficiencies...
in the proper sequence. In full-pallet DCs, operators may be directed to take entire pallets from the racking directly to the truck. Voice-directed truck-loading can help ensure that trucks are loaded in the correct sequence and that all pallets make it onto the truck.
Apart from training users to use the voice system, the system must be trained to understand each user. This training process takes roughly 30–45 minutes – during this time, the user is asked to repeat aloud the words they will be using when they communicate with the system. The voice system learns how the particular operator speaks, and saves a template of their speech patterns. This allows voice systems to understand users with heavy accents – the system knows how each individual user pronounces each word.
There are two types of voice solution – speaker dependent and speaker independent. The former requires the training of each user the second requires only operator training.
With the additional security provided by voice, it is easier to enforce particular rules. For example, you could (if your WMS supports it) create job templates for each user. This means that you could, specify which users were qualified to use a reach truck – and prevent others from receiving these assignments.
WMS or middleware
Being a relatively new technology, only a few warehouse management systems or WMS are specifically designed to support voice direction. Middleware is often required to act as an agent between the WMS and the voice system – and to provide additional functionality such as job assignments, productivity monitoring, etc., that most WMS systems cannot provide out of the box.