SEBARES - Design and Evaluation of a Controller for a novel externally guided self-balancing patient rescue aid

摘要

Paramedics frequently perform physically demanding tasks during patient transport. This leads to extremely high rates of work-induced injuries and early retirement. A novel self-balancing rescue aid (SEBARES) with an additional stair climbing mechanism, which is externally guided by a paramedic, is supposed to reduce the workloads and allowing an intuitive operation and safe transport for the patient. For the self-stabilizing functionality precise and stable control at any time is crucial. In this study a sliding mode controller, which is known for robust and stable control of nonlinear applications, is designed and implemented as a first control approach for such a device. To rate the performance application specific control requirements are defined, which address critical scores such as ergonomic user forces, maximal tilt angles and maximal overshoot. In the subsequent experimental evaluation the performance of the device and the controller are determined. The sliding mode controller successfully stabilized the system and met the predefined requirements. The system was able to accelerate adequately to match typical accelerations of walking humans, forces below 20 N had to be applied during constant walking and the system was able to decelerate from 1.4 m/s to a full halt within a sufficient distance of maximal 0.41 m. Upcoming studies will include a comparative analysis of different control approaches as well as the development of the stair climbing kinematics and obstacle detection.