A Comparative study of Conventional & Proposed Drive System

The main objective of this work revolves around the design of second order sliding mode controllers (SOSMC) based on the super twisting algorithm (STA) for asynchronous permanent magnet motor (PMSM) fed by a direct matrix converter (DMC), in order to improve the effectiveness of the considered drive system. The SOSMC was selected to minimize the chattering phenomenon caused by the conventional sliding mode controller (SMC), as well to decrease the level of total harmonic distortion (THD) produced by the drive system. In addition, the literature has taken a great interest in the STA due to its robustness to modeling errors and to external disturbances. Furthermore, due to its low conduction losses, the space vector approach was designated as a switching law to control the DMC. In addition, the topology and design method of the damped passive filter, which allows improvement of the waveform and attenuation of the harmonics of the input current, have been detailed. Finally, to discover the strengths and weaknesses of the proposed control approach based on SOSMC, a comparative study between the latter and that using the conventional SMC was executed. The results obtained confirm the effectiveness of SOSMC over the conventional SMC under different operating conditions.

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Design and Modeling of a New Drive System and Exaggerated Rectilinear-Gait for a Snake-Inspired Robot

Journal of Mechanisms and Robotics ◽

10.1115/1.4025750 ◽

2014 ◽

Vol 6 (2) ◽

Cited By ~ 19

Author(s):

James K. Hopkins ◽

Satyandra K. Gupta

Keyword(s):

Comparative Study ◽

Friction Force ◽

High Speed ◽

Drive System ◽

Positive Trend ◽

Rectilinear Motion ◽

Linear Motion ◽

Body Structure ◽

Highly Effective ◽

Variable Friction

In recent years, snake-inspired locomotion has garnered increasing interest in the bio-inspired robotics community. This positive trend is largely due to the unique and highly effective gaits utilized by snakes to traverse various terrains and obstacles. These gaits make use of a snake's hyper-redundant body structure to adapt to the terrain and maneuver through tight spaces. Snake-inspired robots utilizing rectilinear motion, one of the primary gaits observed in natural snakes, have demonstrated favorable results on various terrains. However, previous robot designs utilizing rectilinear gaits were slow in speed. This paper presents a design and an exaggerated rectilinear gait concept for a snake-inspired robot which overcomes this limitation. The robot concept incorporates high speed linear motion and a new multimaterial, variable friction force anchoring concept. A series of traction experiments are conducted to determine appropriate materials to be used in the friction anchor (FA) design. The gait concept includes four unique gaits: a forward and a turning gait, which both emphasize speed for the robot; and a forward and turning gait which emphasize traction. We also report a comparative study of the performance of prototype robot designed using these concepts to other published snake-inspired robot designs.

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