Ergonomics, the science that designs environments, equipment, tools and tasks within the capabilities of people to maximize productivity, efficiency and safety, has been an important and highly visible part of the material handling industry for many decades. This is in part because manual material handling work is physically demanding and remains one of the most hazardous jobs in the United States1.
A variety of equipment, tools and technologies have been developed to reduce the frequency of heavy lifting, awkward and/or sustained back, shoulder and wrist postures, and contact stressors during manual material handling tasks. Common administrative policies designed to reduce worker fatigue and risk factors for musculoskeletal injury include designing jobs that have varying work tasks, flexible work pace, job rotation between high and lower workload tasks and break schedules that allow muscles to recover from strenuous work tasks.
In 2007, Cal/OSHA, NIOSH, CNA Insurance Companies, and MHI’s Ergonomic Assist Systems & Equipment (EASE) Industry Group partnered to produce advisory guidelines to improve manual material handling practices2. The document includes recommendations such as encouraging management to eliminate unnecessary manual material handling through improved workflow, eliminating floor-level lifting, minimizing carrying, lifting and lowering distance through improved job and workstation design, providing equipment, conveyors or slides for transporting material, and other things such as training employees on safe manual lifting practices. Informative example solutions are provided throughout the document to help industry put the guidelines to practice.
EASE has also made available one of the most comprehensive online sets of ergonomics material handling solutions. It includes detailed guidance on the selection and use of material handling assist and safety equipment, and case studies that demonstrate the benefits of ergonomics solutions in material handling (see: mhi.org/ease/resources). These resources are valuable tools for the effective ergonomic design of material handling operations.
The new generation of smart automation brought via Industry 4.0 is having transformative effects on the material handling industry. The automation provides opportunities to achieve much higher efficiencies in the supply chain and day to day operations within facilities, and allows material handling to be completed in ways that were not previously possible.
Industry 4.0 technologies have also ergonomics challenges for the material handling industry. Instead of purchasing a cart, height adjustable pallet lift, or vacuum lift to assist a worker during manual material handling, the manager may now be required to consider the complex economic and productivity trade-offs of investing in smart automation to replace manual material handling work. For example, they need to ask which manual material handling activities should now be automated, shared between robots and people, or continue to be performed only by people? How should people communicate and physically interact with a smart robot? How can wearable automation augment human performance in material handling?
Smart collaborative robotics (cobots) are Industry 4.0 technologies that have dramatically changed the role of humans in industrial and material handling work. Cobots are programmed to be able to work with humans as opposed to replacing humans. Ideally, cobots perform the most demanding, tedious, repetitive activities while nearby workers perform the lighter and/or more skilled activities. However, integrating ergonomics into the design of collaborative robot-human workstations is not as easy as it may first seem3. There are many questions that must be first answered. E.g., For a given a set of job tasks, which should be replaced by the cobot and which should be continued by the worker to increase the overall efficiency of the operation? When tasks are reallocated between cobots and humans, is the intended ergonomic impact achieved? Does the introduction of cobots introduce new risks to work-related musculoskeletal disorders by reducing the variability if manual work tasks or changing the working postures of nearby workers in undesirable ways?
Autonomous mobile robots (AMRs) are a form of cobot that is becoming increasingly used in warehouse, retail and manufacturing facilities. AMRs use machine learning and integrated sensors to replace manual material handling (e.g. product picking), transport and loading AMRs include automated pallet movers, shelving systems and automated product picking systems. They have flexible picking and route demands that are sometimes shared with humans, are able to bring material to and from humans, and require less floor space and are more flexible than fixed conveyor systems for material handling.
The benefits of employing AMRs instead of people for material handling tasks is dependent on many things such as the volume of material handling, weight and size of material handled and manual labor versus technology costs. AMRs have a cost including required programming, maintenance, and technical support. Workers who perform complementary or redundant tasks must be trained on how to communicate with or otherwise safely and effectively co-exist with AMRs. AMRs are increasing being used for high demand material handling and transport tasks in environments that can be easily navigated (e.g., clear, flat, predictable). As machine learning and sensing technology improves, the number, types and complexity of the work environments for which AMRs will serve as viable material handling options will increase.
The use of wearable passive (unpowered) and active (powered) exoskeleton technologies have begun to be introduced and tested in the manufacturing, material handling, construction and military settings. Active exoskeleton technologies include frame structures, mechanical components, sensors, actuators, and algorithms that together support motor function and body mechanics of workers during physically demanding tasks. The exoskeleton reduces the loading on a person’s joints and/or increases a person’s capacity during physical tasks that require overhead work, sustained trunk bending or kneeling, and material handling. However, exoskeletons can be awkward to use, particularly when the work requires frequent arm, trunk or leg movement. Exoskeletons can also alter the working postures that individuals normally use when performing tasks. The number of manual handling jobs or job tasks that can truly benefit from the use of exoskeletons is currently unclear. Once promising applications are identified, the device fit, required training, comfort, and safety also need to be further considered. There is still a lot of research and field testing needed before exoskeletons become an ergonomics intervention with benefits that are well understood4.
Ergonomics considerations associated with the increased adoption of Industry 4.0 technologies will continue to focus on how to combine robotic automation and humans to successfully complete work. New ergonomics resources that provide detailed guidance and case examples are needed to help managers ensure that Industry 4.0 technologies are systematically deployed under the right conditions to ensure the improved productivity, efficiency and safety in material handling work.
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Occupational Exoskeletons, IISE Transactions on Occupational Ergonomics and Human Factors, 7:3-4, 153-162, DOI: 10.1080/24725838.2019.1709695.