Kraken: a wirelessly controlled octopus-like hybrid robot utilizing stepper motors and fishing line artificial muscle for grasping underwater

Micro-stepping for Stepper Motors

Stepper motor performance can be compromised by noise and vibration, but an advanced high-torque micro-stepping algorithm can minimise the impact of both noise and vibration as well as increasing the resolution of the rotations. The embedded microcontroller which hosts the micro-stepper algorithm also provides additional flexibility to integrate current-limiting as well as adjusting the drive c...

A Robot for Brain–Controlled Grasping

In this paper we present a system that allows patients with motor disabilities to grasp everyday objects. A closed-loop Brain– Machine Interface (BMI) instantiates a connection between the human central nervous system and an industry robot designed to execute the grasping task. Two central problems were addressed in this paper, namely I) the implementation of a BMI to translate a subject’s volu...

Torque Ripple Minimization in Hybrid Stepper Motors Using Acceleration Measurements ?

Hybrid stepper motors (HSMs) are commonly used in many cost-sensitive industrial and consumer applications. With the use of micro-stepping techniques, they could theoretically achieve a very high resolution in positioning of mechanical loads, even without position sensors. However, it is well known that HSMs are affected by a large torque ripple, due to cogging and phase unbalancing. This, in t...

Speed Control Methods for Stepper Motors

Stepper Motors Uncovered ( 1 ) Part 1 : stepper motor fundamentals

36 Elektor Electronics 11/2003 Often a mechanical operation is required in an application to accurately position a load or device. While a conventional DC or AC motor can be used, it is difficult to determine the exact position of the load, motor speed, or how much total motion has been produced, unless external positioning sensors, encoders, servo loops, and controlling devices (brakes or clut...