
Ethical Use Case
The assistive robot system that has been developed based on the proposed design method is explained. The robot has been developed to assist the user’s walking, sit-to-stand, and stand-to-sit motions. It estimates the user’s state by using a machine learning algorithm and decides on its action based on the result of the estimation.
Use case: Unveiling Stakeholder Dynamics and Information Needs in System Development
Case Number: 0301
Version: 1.2 (2023.11.28), 1.1 (2023.11.23), 1.0 (2023.11.21)
Author: Mizuki Takeda
Background: Use cases mainly depend on the types and functions of the system.
Developers of systems invariably consider use cases of the systems, and SysML Use Case Diagrams can help their considerations and discussions. Developers tend to focus only on use cases of users; however, there are other stakeholders for the systems. Almost all systems have users, engineers, and accident investigators as stakeholders. In the cases of assistive robots, surrounding people such as caregivers or family and certification authorities, can be stakeholders. Who interacts with the system and how is deeply connected to who needs what information, and thus use cases are important for information representation. For example, users often want to know the system’s behavior, state, or action. People become anxious if there is an autonomous robot doing something incomprehensible. Not only current behaviors or actions but also knowledge of future plans is required by users. Depending on circumstances, they want to know the reason for the system’s actions. If there is a difference between the intended action of the user and that of the system, people want to know the reason and a solution. Therefore, ‘what should I do’ is one of the most important pieces of information for systems that include interaction with humans. Engineers relate to systems not only in developing but also maintenance and repair. They can conduct their work more efficiently if they understand the system. To check whether the system is behaving normally or not, information on the system’s internal and external behaviors are required. This knowledge is also useful for accident investigators to investigate accidents.