Engineering design of an adaptive rocking bed for investigating the effects of rocking stimulation sleep

Despite today’s technological advances, sleep impairments and deprivations in adults and seniors have not yet converged to a deterministic intervention. Recent findings in the new-emerged neuroengineering field reveal a promising nonmedication-based solution as the rocking stimulation effects in optimum settings on sleep. This stimulation accelerates sleep initiation and in general, it will improve the sleep architecture in a healthy population. In this research study, we designed an adaptive Rocking Bed system that replicates this stimulation in a systematic engineering design process. We first developed multiple feasible alternatives and identified the best candidate in a two-step decision-making process. The opted concept was subsequently developed further in the preliminary stage considering system requirements, safety, and ease of fabrication and assembly. According to the system requirements, a desired harmonic linear trajectory with variable excitation frequency and amplitude for the application was considered. By defining the motor motion profile, the proprietary AC servo motor and ACME leadscrew actuator were sized for this application. The design was oriented toward quiet operation and direct drive use. For the motion controller aspect, to ensure attaining a high-quality rocking stimulation, we utilized an AC servo drive with a cascaded PID controller. Thus, a PID motion controller was modeled in Simulink for simulation and tune-up purposes. The developed model showed that the system accurately traces the commanded sinusoidal motion profile for the proposed system with a 7.79:1 inertia ratio. The system was also analyzed in terms of safety of the applied loads on the actuator using the motor sizing verification with Solidworks Motion Analysis (rigid-body dynamics), and structural safety in ANSYS. The analyses confirmed the validity of the designed system. The design was finalized by incorporating some safety measures in the system and the bill of material was generated for the whole system