This paper presents a structured methodology for the rapid development of modular robots designed to capture and address user requirements in care settings. While co-design is widely applied in robotics, existing approaches often lack detailed, step-by-step frameworks. This study employs a Design Research (DR) methodology to establish a comprehensive process, demonstrated through the development of a modular robot, Robobrico, in collaboration with a users from an Assisted Living Home during the COVID-19 pandemic. The number of participants was limited to five to facilitate the management, structuring, and coordination of user feedback. The proposed methodology follows a seven-step structured process that systematically captures and clusters user requirements while integrating iterative feedback to refine modular robot variations. Design for Additive Manufacturing (DfAM) is used to accelerate prototype production, enabling rapid iterations informed by user input. This approach enhances the adaptability of care and service robots, ensuring they align more effectively with user needs by encouraging active engagement throughout the design process. This research summarize the methodology, the tools developed to capture and assess user requirements, and the evaluation of progress and insights gained. The findings provide a replicable framework for participatory robot design in care environments, contributing to the broader research community.