Smooth motion is critical to some robotic applications such as haptics or those requiring high precision force control. These systems are often direct-drive, so any torque ripple in the motor output must be minimal. Unfortunately, low inherent torque ripple motors are expensive. Low cost brushless DC motors are becoming more prevalent, especially from the hobby RC community. These motors often ...

Abstract: A novel modular arc-linear flux-switching permanent-magnet motor (MAL-FSPM) used for scanning system instead of reduction gearboxes and kinematic mechanisms is proposed and researched in this paper by the finite element method (FEM). The MAL-FSPM combines characteristics of flux-switching permanent-magnet motor and linear motor and can realize the direct driving and limited angular mo...

In case of high-speed maglev trains, the propulsion force of their Linear Synchronous Motor (LSM) is an essential performance element since the LSM is responsible for both the propulsion and levitation of the train. A large thrust force ripple causes vibration, noise and severe levitation disturbance during the train operation. Because of these reasons, efforts must be made to reduce the thrust...

Permanent Magnet Machines (PMM) with a phase number (m) higher than three allow redundancy and lower torque ripple compared to their three phase counterparts. In this paper, a six phase permanent magnet machine with surface rotor magnets, designed with fractional slot tooth winding is proposed. A stator design with fractional slot tooth winding allows the design of a compact machine through sho...

A NBI heated discharge is modeled with TRANSP under the HL-2A condition. LH wave is injected into the target plasma heated by NBI with a nearly symmetric power spectrum to control the current profile. Due to the off-axis driven current and electron heating, an optimized q-profile, of which the magnetic shear is weak in the central region and negative in the mid-plasma region (x~0.5-0.65), is fo...

Based on the analysis of the principle of torque ripple with commutation time for brushless DC motor, this paper proposes a method to restrain commutation torque ripple. This method is an improved predictive current control. First, an expression is built about the torque ripple during commutation time. After analysis, the non-commutation phase current is related to torque ripple. Then, a kind o...

Using new large-scale wave-flume experiments we examine the cross-section and planform geometry of wave-formed ripples in coarse sand (median grain sizeD50 = 430 μm) under high-energy shoaling and plunging random waves. We find that the ripples remain orbital for the full range of encountered conditions, even for wave forcing when in finer sand the ripple length λr is known to become independen...

The effect of intrinsic ripples on the mechanical response of the graphene monolayer is investigated under uniaxial loading using molecular dynamics (MD) simulations with a focus on nonlinear behavior at a small strain. The calculated stress-strain response shows a nonlinear relation through the entire range without constant slopes as a result of the competition between ripple softening and bon...

High frequency oscillations are associated with normal brain function, but also increasingly recognized as potential biomarkers of the epileptogenic brain. Their role in human cognition has been predominantly studied in classical gamma frequencies (30– 100 Hz), which reflect neuronal network coordination involved in attention, learning and memory. Invasive brain recordings in animals and humans...

Electrophysiological studies in mammal primary auditory cortex have demonstrated neuronal tuning and cortical spatial organization based upon spectral and temporal qualities of the stimulus including: its frequency, intensity, amplitude modulation and frequency modulation. Although communication and other behaviourally relevant sounds are usually complex, most response characterizations have us...