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Wheelchairs equipped with fixed positioned robotic arms is proposed to help paralyzed people. However, such a configuration makes it hard for the users to orient the wheel chair such that the task in need lies within the arm workspace. In this work a robotic arm that slides over a track mounted over a wheelchair is proposed to attain much wider workspace, at no extra complexity of arm design. Proposed design also reliefs the need to orient the wheelchair for extra user comfort. This work represents the Kinematic equations, Dh-parameters and dynamic modeling & simulation of an RRR robotic arm moving along a path built onto a wheelchair including the 3D workspace of the system. Preliminary results show robotic arm can achieve a very dexterous workspace at no extra cost in terms of arm torques yet offering a great comfort for wheelchair users.

Due to their various promising potential applications in the field of structural control, semi-active control of Magneto-Rheological (MR) dampers has been enjoying significant research focus for more than two decades. In this paper, a new direct voltage control algorithm for the MR damper is proposed to enhance the seismic response of civil structures. The MR dampers are represented using a modified Bouc-Wen model. A mathematical model representing a 3-story frame building with MR dampers at the ground floor in a chevron brace configuration, is used for the simulations. The proposed control law shows a high ability of attenuating structural response (floor accelerations and displacements). Simulations of the structural response under to the El Centro earthquake ground motion, are used to demonstrate the efficiency of the proposed control algorithm. The proposed control algorithm performance compares very well against other control algorithms available in the literature given its inherent relative simplicity.

Conventional shooting practice systems are expensive, life threatening, and lack proper statistical evaluation of trainee's performance. This paper presents the implementation and testing of a proposed evolutionary laser shooting practice system for early shooting practice stages. Presented system consists of a real gun replica equipped with lasers rather than live ammunition, a simple CCD camera, a shooting target, and a Compact Vision System (CVS) running National Instruments LabVIEW software. In order to detect con-centric rings of the shooting target an image processing algorithm is developed and employed by the CVS. In addition, the developed algorithm distinguishes locations of trainee's laser shots relative to the center point of the shooting target. For each training session, the system delivers a detailed overall performance report including scores of shooter accuracy and precision. The system was tested at a 100 m long shooting range under different camera-to-target angles and various lighting conditions. Results proved robust performance with accurate and detailed shooting reports under all tested conditions. Presented system overcomes conventional shooting practice systems in terms of cost, safety, evaluation accuracy and portability.

In sound source localization, there is a fundamental size limit; the smaller the size, the smaller the directional cues that are relied on to pinpoint the sound source. As such, it is challenging to develop miniature sound source localization robotic system where space is too confined to employ conventional microphone arrays without compromising localization performance. Our previous studies show that through mechanical coupling with well-tuned structural parameters, directional microphones inspired by the parasitic fly Ormia ochracea can amplify the minute interaural time delay (ITD) by more than ten times, which enables the reduction of device size significantly while maintaining localization performance. In this paper, Cramer Rao lower bound (CRLB) is derived for the fly-ear inspired sensor and the conventional directional microphones to study the effects of mechanical coupling on the decrease of the theoretical lower bound of azimuth estimation. This improvement gives mobile robots the capability to reactively localize sound in an indoor environment. Using this miniature sensor, new sound source localization method is proposed to localize a stationary sound source in 2-D (azimuth and elevation). In the proposed sound localization method, Model-Free Gradient Descent (MFGD) optimization method, one of the main challenges is to choose the appropriate cost function to achieve minimum number of iterations and the smallest absolute error. To this end, different cost functions are proposed and investigated with different control schemes. Simulation results showed the ability of this technique to solve the ambiguity problem and localize the sound source.Copyright © 2012 by ASME