Position and torque control via rehabilitation robot and functional electrical stimulation

Model Predictive Control of a Feedback-Linearized Hybrid Neuroprosthetic System With a Barrier Penalty

Functional electrical stimulation (FES) is prescribed as a treatment to restore motor function in individuals with neurological impairments. However, the rapid onset of FES-induced muscle fatigue significantly limits its duration of use and limb movement quality. In this paper, an electric motor-assist is proposed to alleviate the fatigue effects by sharing work load with FES. A model predictive control (MPC) method is used to allocate control inputs to FES and the electric motor. To reduce the computational load, the dynamics is feedback linearized so that the nominal model inside the MPC method becomes linear. The state variables: the angular position and the muscle fatigue are still preserved in the transformed state space to keep the optimization meaningful. Because after feedback linearization the original linear input constraints may become nonlinear and state-dependent, a barrier cost function is used to overcome this issue. The simulation results show a satisfactory control performance and a reduction in the computation due to the linearization.

An Established Early Rehabilitation Therapy Demonstrating Higher Efficacy and Safety for Care of Intensive Care Unit Patients

BACKGROUND Although survival rates of critically ill patients in Intensive Care Units (ICUs) have improved in recent years, many risk factors cause a few serious complications. This study aimed to evaluate efficacy and safety of comprehensive early rehabilitation therapy for ICU patients. MATERIAL AND METHODS This study recruited ICU patients who were diagnosed as having cerebral hemorrhage or traumatic brain injury. ICU patients were randomly divided into an early rehabilitation therapy group (Observation group, n=21) and a Control group (n=21). Patients in the Control group underwent persistent monitoring of respiratory functions and blood oxygen saturation, as well as electrocardiographic monitoring. ICU patients in the Observation group underwent individualized treatments based on conventional treatments. APACHE II scores, MRC scores, and consciousness improvement rates of ICU patients were evaluated. Incidences of adverse events and complications were also assessed. RESULTS Early rehabilitation therapy significantly decreased APACHE II scores and significantly increased MRC scores compared to the Control group (p<0.05). Early rehabilitation therapy significantly improved consciousness of ICU patients compared to the Control group (p<0.05). Early rehabilitation therapy significantly reduced the incidence of complications compared to the Control group (p<0.05). Early rehabilitation therapy significantly shortened ICU or total hospital stay and mechanical ventilation time compared to the Control group (p<0.05). CONCLUSIONS Early rehabilitation therapy decreased APACHE II scores, enhanced MRC scores, and improved consciousness of ICU patients. Moreover, early rehabilitation therapy also reduced the incidence of complications and shortened ICU or total hospital stay and mechanical ventilation time of ICU patients. Therefore, early rehabilitation therapy was shown to be effective and safe for ICU patients.