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It is proposed to use weighted least-norm solution to avoid joint limits for redundant manipulators. A comparison is made with the gradient projection method for avoiding joint limits. While the gradient projection method provides the optimal direction for the joint velocity vector within the null space, its magnitude is not unique and is adjusted by a scalar coefficient chosen by triaC and error. It is shown in this paper that onefixsd value of the scalar coeffiient is not suitable even in a small workspace. The proposed manipulation scheme automatically chooses an appropriate magnitude of the self motion throughout the workspace. This scheme, unlike the gradient projection method, guarantees joint limit avoidance, and also minimizes unnecessary self motion. It was implemented and tested for real-time control of a seven-degree-of-freedom (7-DoF) Robotics Research Corporalion (RRC) manipulator.

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In this article, a virtual reality system for vocational rehabilitation of individuals with disabilities (VR4VR) is presented. VR4VR uses immersive virtual environments to assess and train individuals with cognitive and physical disabilities. This article focuses on the system modules that were designed and developed for the Autism Spectrum Disorder (ASD) population. The system offers training on six vocational skills that were identified as transferrable to and useful in many common jobs. These six transferable skills are cleaning, loading the back of a truck, money management, shelving, environmental awareness, and social skills. This article presents the VR4VR system, the design considerations for the ASD population, and the findings with a cohort of nine neurotypical individuals (control group) and nine high-functioning individuals with ASD (experiment group) who used the system. Good design practices gathered throughout the study are also shared for future virtual reality applications targeting individuals with ASD. Research questions focused on the effectiveness of the virtual reality system on vocational training of high-functioning individuals with ASD and the effect of distracters on task performance of high-functioning individuals with ASD. Follow-up survey results indicated that for individuals with ASD, there was improvement in all of the trained skills. No negative effects of the distracters were observed on the score of individuals with ASD. The proposed VR4VR system was found by professional job trainers to provide effective vocational training for individuals with ASD. The system turned out to be promising in terms of providing an alternative practical training tool for individuals with ASD.