Industrial exoskeletons are globally developed, explored, and increasingly implemented in industrial workplaces. Multiple technical, physical, and psychological aspects should be assessed prior to their daily application in various occupational environments. The methodology for evaluating these aspects is not standardised and differs in terms of focussed research objectives, used types of analyses, applied testing procedures, and use cases. The aim of this paper is to provide a matrix comparing the prevalence of different types of analyses combined with their respective research objective(s). A systematic review in the database ‘Web of Science’ identified 74 studies, mainly in laboratory settings, with a focus on short-term effects as well as with male-dominated samples being low representative for industrial workforces. The conducted evaluation methodologies are further discussed and compared in terms of testing procedure, sample, and research objectives. Finally, relevant aspects for prospectively evaluating industrial exoskeletons in a more harmonised and comprehensive way are suggested. Practitioner summary: Industrial exoskeletons are still inconsistently and insufficiently evaluated in scientific studies, which might hamper the comparability of systems, threaten the human health, and block an iterative system optimisation. Thus, a comprehensive evaluation methodology is needed with harmonised and multicriteria types of analyses.

In recent years, the trend for implementing exoskeletons in industrial workplaces has significantly increased. A variety of systems have been developed to support different tasks, body parts, and movements. As no standardized procedure for evaluating industrial exoskeletons is currently available, conducted laboratory and field tests with different setups and methodologies aim to provide evidence of, e.g., the support for selected isolated activities. Accordingly, a comparison between exoskeletons and their workplace applicability proves to be challenging. In order to address this issue, this paper presents a generic method and modular test course for evaluating industrial exoskeletons: First, the seven-phase model proposes steps for the comprehensive evaluation of exoskeletons. Second, the test course comprises a quick check of the system’s operational requirements as well as workstations for an application-related evaluation of exoskeletons’ (short-term) effects. Due to the vastness and heterogeneity of possible application scenarios, the test course offers a pool of modular configurable stations or tasks, and thus enables a guided self-evaluation for different protagonists. Finally, several exemplary exoskeletons supporting varying body regions passed the test course to evaluate and reflect its representativity and suitability as well as to derive discernible trends regarding the applicability and effectiveness of exoskeleton types.

In modern times, the collaboration between humans and machines increasingly rises, combining their respective benefits. The direct physical support causes interaction forces in human–machine interfaces, whereas their form determines both the effectiveness and comfort of the collaboration. However, their correct detection requires various sensor characteristics and remains challenging. Thus, this paper presents a developed low-cost sensor pad working with a silicone capsule and a piezoresistive pressure sensor. Its measurement accuracy is validated in both an isolated testing environment and a laboratory study with four test subjects (gender-balanced), and an application integrated in interfaces of an active upper-body exoskeleton. In the material-testing machine, it becomes apparent that the sensor pad generally features the capability of reliably determining normal forces on its surface until a certain threshold. This is also proven in the real application, where the measurement data of three sensor pads spatially embedded in the exoskeletal interface are compared to the data of an installed multi-axis load cell and a high-resolution flexible pressure map. Here, the consideration of three sensor pads potentially enables detection of exoskeletal support on the upper arm as well as “poor” fit conditions such as uneven pressure distributions that recommend immediate system adjustments for ergonomic improvements.

The applicability of exoskeletons in different daily and occupational settings is continually increasing. Due to varying tasks and user groups, the adaptability of exoskeletons is becoming more significant, with increasing demands for smarter devices. The implementation of force sensors in exoskeletal interfaces could be an approach for analyzing the human-machine interaction in terms of, e.g., wearing comfort, support, and motion synchronicity, as well as optimizing this interaction in real time based on the analyzed sensory data. For this, force sensors need to be embedded in interfaces, which implies the consideration of inexpensive sensors to minimize the total purchase price. However, measuring contact forces on the wearer is challenging and inexpensive flexible force sensing resistors have limited accuracy, repeatability, and stability. This paper evaluates the suitability of an interface principle working with two water capsules and two embedded piezo-resistive pressure sensors in different test scenarios derived from real exoskeletal application examples. Finally, a comparison of the capsules’ inner pressures reliably detects different load conditions on the interface such as centered, edged, and shear forces. Thus, this principle seems to be suitable for further exoskeletal considerations.

Assistive devices like exoskeletons undergo extensive testing not least because of their close interaction with humans. Conducting user studies is a time-consuming process that demands expert knowledge, and it is accompanied by challenges such as low repeatability and a potential lack of comparability between studies. Obtaining objective feedback on the exoskeleton’s performance is crucial for developers and manufacturers to iteratively improve the design and development process. This paper contributes to the concept of using robots for objective exoskeleton testing by presenting various approaches to a robotic-based testing platform for upper-body exoskeletons. We outline the necessary requirements for realistically simulating use cases and evaluate different approaches using standard manipulators as robotic motion generators. Three approaches are investigated: (i) Exploiting the anthropomorphic structure of the robotic arm and directly placing it into the exoskeleton. (ii) Utilizing a customized, direct attachment between the robot and exoskeleton. (iii) Attaching a human arm dummy to the robot end effector to simulate a more realistic interface with the exoskeleton. Subsequently, we discuss and compare the results against the aforementioned requirements of a systematic testing platform. Our conclusion emphasizes that achieving objective and realistic testing necessitates highly specialized hardware, algorithms, and further research to address challenging requirements.