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Over the past years, robot-aided rehabilitation has gained traction to regain lost mobility in upper limb due to stroke. In most cases, rehabilitative robotic devices have not considered movement of shoulder joint center (center of glenohumeral joint); however, this movement leads to misalignment of human joints with robot joints, which is undesirable in any circumstances. In this research, a 2 degrees of freedom (DOF) ergonomic robotic shoulder, namely RDS-2, was developed to realize full range of motion (ROM) for abduction/adduction and vertical flexion/extension. Two mechanisms, which were designed in our previous research, have been included to realize shoulder elevation/depression and shoulder protraction/retraction during shoulder movement. To control the exoskeleton, a simple hybrid non-liner control approach based on model robot's dynamic model and its tracking error was developed. The stability of the controller was proved by Lyapunov stability. Experiments were done with slow, medium and fast pre-determined trajectories to see the efficacy of the used controller. The results show stability and robustness of used control approach for developed ergonomic shoulder. [ABSTRACT FROM AUTHOR]

As the stress of gears determines the reliability of transmission, the stress research of face gear drive has great significance from the perspective of both theory and practice. The finite element model of orthogonal spur face gear meshing is attained via root-top section lofting method. The geometry parameters (include modulus, teeth number of face gear, teeth number of pinion and pressure angle) and transmission parameter (nominal contact force) are considered in the stress modeling. This paper, respectively established the empirical equations for contact stress and bending stress of face gear and pinion through stepwise regression by using single factor test and orthogonal test. The empirical equations have been validated by comparing them with results obtained from FEA. [ABSTRACT FROM AUTHOR]

To control microelectromechanical systems (MEMS) gyroscope axis, we propose and investigate a new robust sliding mode controller (NRSMC). The sliding surface in the phase space converges to the equilibrium point within a finite period from any initial state. However, the main drawback of this control system is the chattering phenomenon, which is undesirable for the MEMS system. To solve this problem, we suggest a novel hybrid control system which improves trajectory tracking and eliminates the chattering. The dynamic stability of NRSMC against external disturbances is proved by applying the Lyapunov theory. The effectiveness of the proposed control method is verified by numerical simulation with a random noise applied to demonstrate the robustness of the proposed control system. [ABSTRACT FROM AUTHOR]

The Micro-Electro-Mechanical System (MEMS) gyroscope is a well-known device, which has been widely used in medicine due to its small size. In this study, a new adaptive fractional integral sliding mode controller is proposed for control of a MEMS gyroscope. The goal is to achieve an appropriate control method that includes high tracking performance and robustness against external disturbances. The fractional order integral sliding mode controller gains will be updated by a new adaptive law. The effectiveness of the proposed controller is validated by simulation results. Results show that the adaptive fractional integral sliding mode control controller successfully tracked the desired trajectory in comparison with the fractional integral sliding mode control method. The Lyapunov theory is used in order to show that the adaptive fractional integral sliding mode control is stable. [ABSTRACT FROM AUTHOR]