41 www.drivesncontrols.com June 2023 WAREHOUSING n disruptive. Redesigning the supply network around new sites and buildings is a challenge because suitable sites and properties are often not available. A well-considered AMR implementation, however, can transform the productivity and the ergonomics of warehouse order-picking, and internal transport more generally. Many retailers have experience of warehouse automation, and not all of it has been happy. Fixed systems such as conveyors are expensive to install, involving extensive electrical and often structural engineering work. They are, by definition, inflexible both in their location and how they are used. They eat up a lot of aisle space and are often incompatible with safe human cooperation. Man-on truck systems may also have safety issues even if driven (as they should be) by people with transferable, and expensive, skills. Some retailers have tried Automated Guided Vehicles (AGVs) but these too are inflexible, being confined to predefined pathways, and can require highquality floor surfaces. Modern AMRs address all these issues. Firstly, autonomy means that, equipped with a “map” of the warehouse layout and locations, they can reach the desired location by working out alternative routes around obstacles or other vehicles. Freeing up space This flexibility means that AMRs are not permanently occupying valuable space with mechanical engineering, nor do particular routes have to be kept free at all times. The software also means that they can be redeployed readily across different internal transport tasks – bringing pallets from goods inward to the replenishment face, or totes to picking stations, or filled roll cages to despatch – as well as supporting various order-picking strategies. A “duo” picking strategy, for example, involves a worker receiving picking instructions by voice, via a radio frequency terminal, or on an order-picking tablet. Picking to the totes, roll cages or other containers is carried by the AMR. This can result in improvements of up to 50% in pick rates compared to purely manual methods. Zonal picking keeps each operator in one picking zone, while the AMR moves between zones depending on the products required. This tends to maximise the number of picks per hour, while minimising operator walking distances. Importantly, some models can accommodate two roll cages with a combined weight of 1,500kg. Operators can work with a pair of AMRs, thus fulfilling four orders at once. These picking techniques also tend to reduce errors. The vehicles themselves are designed to operate safely alongside human co-workers with Lidar providing all-round visual protection, supplemented by 3D cameras to detect obstacles ahead at heights from 30mm to 1.9m above the floor level. Top speeds of around 7km/h are equivalent to brisk walking speed and there are routines that ensure safe cornering speeds and braking distances. Grocers with cold stores, in particular, appreciate that, thanks to some clever engineering, AMR batteries and electronics can be kept warm and condensation-free at temperatures down to –25°C, so the same AMRs can do a shift in and out of the cold store if desired. Battery lives between charges can be 12-18 hours, so two busy shifts should be achievable before charging (which takes two hours) is needed. A curse for large retailers is the number of formats for the containers in which they receive goods. The “standard” pallet is a bit of a myth and there may be all manner of totes, crates, bread trays and the like. Similarly, the AMR may be required to load from, or unload to, a variety of other pieces of automation equipment. At iFollow, we have developed lifting platforms with slat, roller, chain or tray roller beds, (or indeed tailored to customers’ own requirements) that can be swapped over easily for new tasks. Perhaps most importantly in these uncertain times is that AMRs offer retailers maximum flexibility. They can accommodate the widest variety of containers, interact with many different items of other equipment, and support a wide range of picking and other strategies and styles which, with warehouses serving customers from megastores to corner shops, can change hour to hour. Because each AMR is a discrete piece of equipment, the installation can be scaled up (or indeed down) as volume requirements change, whether that be due to economic conditions, or to factors such as seasonality. Indeed, if an entire warehouse layout needs to be redesigned, all that is required is a new “map” in the software, and the AMRs are good to go. The investment in the technology is, to a large extent, future-proofed. n AMR-based picking systems can result in improvements in pick rates of up to 50% over purely manual methods
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