ระบบควบคุมแบบไฮบริดโดยอิงแรงและสัญญาณไฟฟ้ากล้ามเนื้อสำหรับหุ่นยนต์ทำกายภาพบำบัด

This paper presents a hybrid control system of rehabilitation robot with force and EMG signals. The proposed control system is implemented on the elbow joint of the 4 DOF universal exoskeleton. Admittance control method is applied to control this rehabilitation robot. However, the transient response of the admittance control cloud lead in a large overshoot when the user moves exoskeleton joint quickly then suddenly stops. Hence, the EMG sensor is used to detect the muscle contraction and then the force input will be set to zero for improving transient response of the hybrid controller. Furthermore, the generalized regression neural network (GRNN) is applied for predicting the static gravity force compensation. The experimental result indicates that the GRNN can predict the static gravity force with accuracy of 97.32%. Moreover, 83.13% of the transient response is improved by the utilization of the EMG signal in the hybrid controller

Active exoskeleton control systems: State of the art

To get a compliant active exoskeleton controller, the force interaction controllers are mostly used in form of either the impedance or admittance controllers. The impedance or admittance controllers can only work if they are followed by either the force or the position controller respectively. These combinations place the impedance or admittance controller as high-level controller while the force or position controller as low-level controller. From the application point of view, the exoskeleton controllers are equipped by task controllers that can be formed in several ways depend on the aims. This paper presents the review of the control systems in the existing active exoskeleton in the last decade. The exoskeleton control system can be categorized according to the model system, the physical parameters, the hierarchy and the usage. These considerations give different control schemes. The main consideration of exoskeleton control design is how to achieve the best control performances. However, stability and safety are other important issues that have to be considered. © 2012 The Authors