Kinematic and kinetic functional requirements for industrial exoskeletons for lifting tasks and overhead lifting

Biomechanical assessment of a passive back-support exoskeleton during repetitive lifting and carrying: Muscle activity, kinematics, and physical capacity

INTRODUCTION

Most people have experienced low back pain (LBP) more or less in their lifetime. Heavier load weight could increase the risk of LBP, especially in repetitive lifting and carrying tasks. The risk could also increase with the frequency of lifting. This study aims to investigate the effects of a passive back-support exoskeleton (PBSE) on trunk muscle activation, kinematics, and physical capacity in a repetitive lifting task and a carrying task in consideration of load weights in a laboratory setting.

RESULTS

Results showed that using the PBSE, the activities of the thoracic erector spinae and lumbar erector spinae muscles were reduced significantly by nearly 7% MVC and 3% MVC in the repetitive lifting task and the carrying task, respectively. There was no significant effect of the PBSE on the spine kinematics and physical capacity.

PRACTICAL APPLICATIONS

This study supports the use of the PBSE to reduce trunk muscle activity in repetitive lifting and carrying tasks.

Biomechanics Analysis of the Firefighters' Thorax Movement on Personal Protective Equipment during Lifting Task Using Inertial Measurement Unit Motion Capture

Back injury is a common musculoskeletal injury reported among firefighters (FFs) due to their nature of work and personal protective equipment (PPE). The nature of the work associated with heavy lifting tasks increases FFs' risk of back injury. This study aimed to assess the biomechanics movement of FFs on personal protective equipment during a lifting task. A set of questionnaires was used to identify the prevalence of musculoskeletal pain experienced by FFs. Inertial measurement unit (IMU) motion capture was used in this study to record the body angle deviation and angular acceleration of FFs' thorax extension. The descriptive analysis was used to analyze the relationship between the FFs' age and body mass index with the FFs' thorax movement during the lifting task with PPE and without PPE. Sixty-three percent of FFs reported lower back pain during work, based on the musculoskeletal pain questionnaire. The biomechanics analysis of thorax angle deviation and angular acceleration has shown that using FFs PPE significantly causes restricted movement and limited mobility for the FFs. As regards human factors, the FFs' age influences the angle deviation while wearing PPE and FFs' BMI influences the angular acceleration without wearing PPE during the lifting activity.

An Occupational Shoulder Exoskeleton Reduces Muscle Activity and Fatigue During Overhead Work

Objective. This paper assesses the effect of a passive shoulder exoskeleton prototype, Exo4Work, on muscle activity, muscle fatigue and subjective experience during simulated occupational overhead and non-overhead work. Methods. Twenty-two healthy males performed six simulated industrial tasks with and without Exo4Work exoskeleton in a randomized counterbalanced cross-over design. During these tasks electromyography, heart rate, metabolic cost, subjective parameters and performance parameters were acquired. The effect of the exoskeleton and the body side on these parameters was investigated. Results. Anterior deltoid activity and fatigue reduced up to 16% and 41%, respectively, during isometric overhead work, and minimized hindrance of the device during non-overhead tasks. Wearing the exoskeleton increased feelings of frustration and increased discomfort in the areas where the exoskeleton and the body interfaced. The assistive effect of the exoskeleton was less prominent during dynamic tasks. Conclusion. This exoskeleton may reduce muscle activity and delay development of muscle fatigue in an overhead working scenario. For dynamic applications, the exoskeleton's assistive profile, which mimics the gravitational torque of the arm, is potentially sub-optimal. Significance. This evaluation paper is the first to report reduced muscle fatigue and activity when working with an occupational shoulder exoskeleton providing one third of the gravitational torque of the arm during overhead work. These results stress the potential of occupational shoulder exoskeletons in overhead working situations and may direct towards longitudinal field experiments. Additionally, this experiment may stimulate future work to further investigate the effect of different assistive profiles.

SMARCOS: Off-the-Shelf Smart Compliant Actuators for Human–Robot Applications

With the growing popularity of Human–Robot Interactions, a series of robotic assistive devices have been created over the last decades. However, due to the lack of easily integrable resources, the development of these custom made devices turns out to be long and expensive. Therefore, the SMARCOS, a novel off-the-shelf Smart Variable Stiffness Actuator for human-centered robotic applications is proposed in this paper. This modular actuator combines compliant elements and sensors as well as low-level controller and high-bandwidth communication. The characterisation of the actuator is presented in this manuscript, followed by two use-cases wherein the benefits of such technology can be truly exploited. The actuator provides a lightweight design that can serve as the building blocks to facilitate the development of robotic applications.

Occupational exoskeletons: A roadmap toward large-scale adoption. Methodology and challenges of bringing exoskeletons to workplaces

The large-scale adoption of occupational exoskeletons (OEs) will only happen if clear evidence of effectiveness of the devices is available. Performing product-specific field validation studies would allow the stakeholders and decision-makers (e.g., employers, ergonomists, health, and safety departments) to assess OEs' effectiveness in their specific work contexts and with experienced workers, who could further provide useful insights on practical issues related to exoskeleton daily use. This paper reviews present-day scientific methods for assessing the effectiveness of OEs in laboratory and field studies, and presents the vision of the authors on a roadmap that could lead to large-scale adoption of this technology. The analysis of the state-of-the-art shows methodological differences between laboratory and field studies. While the former are more extensively reported in scientific papers, they exhibit limited generalizability of the findings to real-world scenarios. On the contrary, field studies are limited in sample sizes and frequently focused only on subjective metrics. We propose a roadmap to promote large-scale knowledge-based adoption of OEs. It details that the analysis of the costs and benefits of this technology should be communicated to all stakeholders to facilitate informed decision making, so that each stakeholder can develop their specific role regarding this innovation. Large-scale field studies can help identify and monitor the possible side-effects related to exoskeleton use in real work situations, as well as provide a comprehensive scientific knowledge base to support the revision of ergonomics risk-assessment methods, safety standards and regulations, and the definition of guidelines and practices for the selection and use of OEs.

A Review of Relevant Regulations, Requirements and Assessment Methods Concerning Physical Load in Workplaces in the Slovak Republic

This review brings an overview of the Slovak regulations concerning occupational safety and health at work (OSH) primarily considering the parameter of physical load. In addition to regulations, this article focuses on particular requirements at workplaces with an increased physical load and describes the permissible values of the physical load (see tables). Attention is given to assessing the working posture and handling of loads. The main purpose of the evaluation is to determine the parameters of physical load, which is the first important step in the process of health risk assessment. Based on the physical load assessment and the categorization of tasks for the physical load factor in the Slovak Republic, further steps and measures should be taken to improve working conditions, to reduce the workload, number of health problems, fatigue, and ultimately to prevent accidents at work and work-related musculoskeletal diseases.