Surface electromyography (sEMG) is a promising technology that can capture muscle activation signals to control robots through novel human–machine interfaces (HMIs). This technology has already been applied in scenarios such as prosthetic design, assisted robot control, and rehabilitation training. This article provides an overview of sEMG-based robot control, covering two important aspects: (1) sEMG signal processing and classification methods and (2) robot control strategies and methods based on sEMG. First, the article outlines the general steps in sEMG signal processing and summarizes the commonly used methods for data acquisition, pre-processing, and feature extraction. In addition, machine-learning-based pattern recognition methods have been introduced for sEMG signal classification. Subsequently, user intent-based robot control strategies are classified into three categories: full-human continuous control, semi-autonomous continuous control, and discrete control, and their control methods and applicable scenarios are compared. Finally, this article discusses the advantages, disadvantages, and future development prospects of sEMG-based robot control. This review provides a comprehensive overview of sEMG-based robot control, from signal processing and classification methods to robot control strategies and methods, aiming to guide future research on selecting filters, feature sets, and pattern recognition methods and to assist in establishing sEMG-driven robot control frameworks.
Porous graphitic carbon nitride (g‐C 3 N 4 ) has been synthesised by means of one‐step calcinations of dicyandiamide for efficient photocatalysis under visible light irradiation (λ > 400 nm). Scanning electron microscopy images demonstrate that the as‐prepared photocatalyst calcined at 650°C is a porous structure. The UV–vis diffuse reflectance spectra show that the optical absorption for the porous g‐C 3 N 4 is more intensive than for common g‐C 3 N 4 calcined at 550°C. The enhanced generation of the photocurrent under visible light irradiation (λ > 400 nm) is observed by using the porous g‐C 3 N 4 . The results of the photocatalytic experiments under visible light irradiation reveal that the photocatalytic degradation of methylene blue using the porous g‐C 3 N 4 is higher than common g‐C 3 N 4 , showing the advantage of the structure for efficient photocatalysis. The presence of the calcinations temperature is presumed to play a key role in adjusting the textural properties.
20 September 2017 in Journal of Dynamic Systems, Measurement, and Control
A method is presented for slip analysis of a wheeled mobile manipulator. The said system consists of an industrial manipulator mounted on a mobile platform performing aircraft manufacturing tasks. Unlike tracked/legged mobile robots that may slip when negotiating slopes or climbing stairs, a wheeled mobile manipulator may slip resulting from the manipulator movement or the forces from the end-effector during fastening. Slip analysis is crucial to ensure pose accuracy for operation. In this study, first a universal friction constraint is used to derive the slip condition of the system. Three cases are considered, with the first case considering the reaction force in relation to the stand-off distance between the mobile manipulator and the workpiece. The second case deals with the joint speeds to investigate the effect of coupling terms including centrifugal forces and gyroscopic moments on slip. The third case deals with the joint accelerations to investigate the effect of inertia forces and moments on slip. Simulations and experiments are carried out to verify the proposed method.
Trajectory planning and avoidance of tipping are the main keys to success in the mobile dual-arm manipulation, especially when the dual-arm or moving platform is running fast. The forces and moments between wheel-terrain and body-arm have been analyzed by kinematics and force analysis of a robot to define tip-over stability constraint. Then, an improved tip-over moment stability criterion for a wheeled mobile dual-arm robot is presented and defines tip-over stability constraint based on it. To improve the motion stability of the robot, this paper presents an optimal joint trajectory planning model based on time and energy. The quintic B-spline curve and an improved NSGA-II algorithm, which are time and energy, are applied to multi-objective optimization. The simulation results show that the motion stability of a robot is improved based on the tip-over stability constraint. This trajectory planning method based on the stability constraint can be applied to other mobile robots as well.
31 August 2014 in Russian Journal of Physical Chemistry A
Graphene oxide modified porous g-C3N4 (porous g-C3N4/GO) had been synthesized by means of one-step calcination of cyanamide for efficient photocatalysis under visible light irradiation (λ > 400 nm)....