A Novel 6‑DOF Force‑Sensed Human‑Robot Interface for an Intuitive Teleoperation

The teleoperation of a 6 degrees-of-freedom(DOF)manipulator is one of the basic methods to extend people’s capabilities in the wide variety of applications.The master interface based on the force/torque(FT)sensor could provide the full-dimension intuitive teleoperation of a 6-DOF robot since it has the ability to trigger 6-DOF command input.However,due to the force coupling,noise disturbance and unlimited input signals of the FT sensor,this force-sensed interface could not be widely used in practice.In this paper,we present an intuitive teleoperation method based on the FT sensor to overcome these challenges.In this method,the input signals from the force-sensed joystick were filtered and then processed to the force commands by force limit algorithm,with the merits of anti-interference,output limitation,and online velocity adjustment.Furthermore,based on the admittance control and position controller,the manipulator could be teleoperated by the force commands.Three experiments were conducted on our self-designed robotic system.The result of the first experiment shows that the interfered force from the force coupling could be effectively suppressed with the limitation of the input force through force limit algorithm.Then,a parameter was introduced in the other two experiments to adjust the velocity online practically with force limit algorithm.The proposed method could give a practical solution to the intuitive teleoperation based on the FT sensor.

Forced vibration analysis of nano-composite rotating pressurized microbeam reinforced by CNTs based on MCST with temperature-variable material properties

In this study, free and forced vibration analysis of nano-composite rotating pressurized microbeam reinforced by carbon nanotubes （CNTs） under magnetic field based on modify couple stress theory （MCST） with temperature-variable material propertiesis presented. Also, the boundary conditions at two ends of nano-composite rotating pressurized microbeam reinforced by CNTs are considered as simply supported. The governing equations are obtained based on the Hamilton＇s principle and then computed these equations by using Navier＇s solution. The magnetic field is inserted in the thickness direction of the nano-composite microbeam. The effects of various parameters such as angular velocity, temperature changes, and pressure between of the inside and outside, the magnetic field, material length scale parameter, and volume fraction of nanocomposite microbeam on the natural frequency and response systemare studied. The results show that with increasing volume fraction of nano-composite microbeam, thickness, material length scale parameter, and magnetic fields, the natural frequency increases. The results of this research can be used for optimization of micro-structures and manufacturing sensors, displacement fluid, and drug delivery.

Stabilized Crouzeix-Raviart element for the coupled Stokes and Darcy problem

This paper introduces a new stabilized finite element method for the coupled Stokes and Darcy problem based on the nonconforming Crouzeix-Raviart element. Optimal error estimates for the fluid velocity and pressure are derived. A numerical example is presented to verify the theoretical predictions.