## 1 Introduction
### Increasing the Technological Readiness of Medical Devices  
Product development consists of different steps that allow a new product or family of products to be brought to market. The process is implemented in different ways, and one challenge is balancing aspects such as function, form, material, and process; therefore, it is important to emphasize the methodology and tools to be used [20].  
In the design process of a medical product, its purpose, fields of application, associated risks, and user benefits must be clearly specified. The main objective of product development is to demonstrate the knowledge available or obtained by the different aspects of the project in prototypes, pilot plants, and models to validate their usefulness in satisfying a need [21].  
It is necessary to know the level of technological development, which is understood as the application of research results, or any other type of scientific knowledge, for the manufacture of new materials or products, in the design of new processes or production systems, as well as in the provision of services [22].  
TRLs are a type of measurement system used to assess the maturity level of a particular technology. The technological maturity of the designs is carried out with the improvement of the development phases of the devices; from the design concept, the experimental physical model and, subsequently, the characteristics of the prototype in relation to the maturity of the product proposed in the TRLs, are reached [23,24]. Each development is evaluated according to the requirements of each technological level which is assigned a TRL rating [22].  
The TRLs were developed to explicitly define the different stages of technology readiness (nine stages), promote common understandings, and facilitate handover among stakeholders [25]. The TRL classification determines how far a particular technology is from being implemented by the industry or the public. This, in turn, determines the number of resources (time, funds, intellectual potential, facilities, etc.) needed to bring such a technology to life [20].  
This paper presents the use of a concurrent methodology for the analysis of the actual positions of ERMIS and its refinement to reach the prototype specifications of the ERMIS exoskeleton. we identified an experimental physical model with a validated operating principle, and the prototype as a device validated in a laboratory environment  
\begin{table}
\begin{tabular}{c c} \hline
**Movement** & **Range of Motion (\({}^{\circ}\))** \\ \hline Shoulder adduction-abduction & 0 to 164 \\ \hline Shoulder flexion–extension & 0 to 173 \\ \hline Internal and external shoulder rotation & \(-86\) to 74 \\ \hline Elbow flexion–extension & 0 to 140 \\ \hline Wrist flexion–extension & \(-53\) to 74 \\ \hline Radial cubital deviation & \(-10\) to \(30\) \\ \hline Pronation and supination & \(-80\) to \(-90\) \\ \hline \end{tabular}
\end{table}
Table 1: Ranges of motion of the ERMIS exoskeleton.  
Figure 1: (**a**) CAD model of the ERMIS exoskeleton and (**b**) EPM of the ERMIS.  
with a permissible performance and minimal changes required in materials and parameters. The methodology seeks to accelerate the transition between the concepts of an experimental physical model and prototype and clarifies the phases in the development of the ERMIS exoskeleton such as engineering, research, development, and innovation.  
The methodology will serve for the future analysis and development of rehabilitation robotics. The design analysis path could be diversified, but not the considerations involved in the methodology.  
This article is organized as follows: Section 2 provides a detailed description of the methodology. In Section 3, the case study methodology is applied for the analysis of points on the ERMIS exoskeleton trajectories. Section 4 presents and discusses the results obtained from the behavior of the ERMIS exoskeleton, finally concluding with the current technical specifications and proposing solutions for increasing the technological maturity of the system.