Estimation of the Continuous Pronation–Supination Movement by Using Multichannel EMG Signal Features and Kalman Filter: Application to Control an Exoskeleton

Abstract

The Hill muscle model can be used to estimate the human joint angles during continuous movement. However, adopting this model requires the knowledge of many parameters, such as the length and speed of contraction of muscle fibers, which are liable to change with different individuals, leading to errors in estimation. This study established the backpropagation neural network model based on surface electromyography (sEMG) features and human movement angle. First, the function of muscles in joint rotation is defined, and then, sensors are placed on muscle tissues to gain sEMG, and then, a relation model between the surface sEMG features and the joint angle is constructed. As integrated electromyography information cannot be well reflected through a single electromyography feature, a feature extraction method combining the time domain, frequency domain, and time–frequency domain was proposed. As the degree of freedom (DOF) of the pronation–supination movement was controlled by several muscles, it was difficult to make an angle prediction. A method of correcting the estimation error based on the Kalman filter was raised to cope with this problem. An exoskeleton robot with one DOF was designed and put into the tracking experiment. The results show that the proposed model was able to enhance the estimation of the joint angle during continuous pronation–supination movements.

Prediction of biceps muscle electromyogram signal using a NARX neural network

“…Numerous studies have applied the neural network as a black box model to model the muscle and have reported successful results. [ 48 ] However, the neural network is usually applied to model or predict part of EMG signal parameters, such as prediction of torque using the NARX neural network,[ 49 ] prediction of the wrist angle based on the intensity of different loads on the muscle using the genetic algorithm,[ 50 ] prediction of the wrist angle based on the neural network and Kalman filter,[ 51 ] and prediction of the EMG signal from the Gait Kinematics and Kinetics using the NARX neural network. [ 52 ]…”