In this study, a sliding mode controlled dual arm robotic system was designed. Such multi-arm, collaborative and synchronous robots typically are employed in hazardous situations such as radioactive materials transport explosives disposal and industrial applications. In the present study, a high performance, robust, non-chattering sliding mode controller (SMC) was developed for the purpose of safe load handling, transportation and trajectory realization. First, dynamic equations of robot/load interaction were derived. Then, the robust SMC was designed for the dual arm robotic system. In order to test the robustness of the proposed SMC, parameter variations and external disturbances were introduced to the system. Furthermore, for comparative purposes, the conventional and widely used, PID controller was also applied to the dual arm robot. Significantly, it was found that the SMC made smaller trajectory tracking errors than the PID controller. An overall analysis of the numerical results confirmed that the dual-arm robotic systems with the proposed SMC can safely and effectively be used in hazardous applications.
Histopathological examination revealed that both LMWH and rivaroxaban have positive effects on tendon healing. However, the same positive effects were not detected in biomechanical examination.
Musculoskeletal simulation and dynamic modeling programs have been used to gain insight into lower-limb musculoskeletal injury mechanisms. In addition to the temporospatial, kinematic, and kinetic data obtained from motion analysis systems, musculoskeletal simulation programs also can provide information on joint contact and muscle forces, musculotendinous lengths and velocities, and muscle activation levels. Musculoskeletal simulation platforms may help in the assessment of risk factors for sports-related injuries. Using musculoskeletal simulations for injury prevention programs may help lower the incidence of sports injuries, and may allow for fast recovery from injury. In this review, injury mechanisms and risk factors of some of the most common lower-limb musculoskeletal injuries, including anterior cruciate ligament, patellofemoral, and hamstring injuries were summarized from a biomechanical perspective. Also, the efficacy of musculoskeletal modeling and dynamic simulation tools in helping our understanding of these injury mechanisms was discussed.
Objective:To assess the histopathologic and biomechanical effects of hyaluronic acid (HA) and high-dose vitamin C (VC) on rat Achilles tendon healing. Methods:Forty-eight Sprague-Dawley rats were randomized to HA and VC and control groups with equal numbers. Each group was further divided into two subgroups to be sacrificed on Day 15 (n=8) and Day 30 (n=8). The Achilles tendons were cut and repaired. While the control rats remained untreated, HA and VC were administered after repair. The repaired tendons were removed for biomechanical and histopathologic analyses. In the biomechanical tests, the tendons were stretched to failure and maximum forces were measured. For histopathologic examination, the specimens were interpreted semiquantitatively using Movin’s grading scale and Bonar scores. Results:The highest mean forces were obtained in the HA group on Day 15 and in the VC group on Day 30, with a significant difference between HA and VC on Day 15 between control and VC on Day 30 (p<0.05). Histological examination showed both Movin and Bonar scores decreased in all groups on Day 30, with significant improvements in the HA and VC groups (p<0.05). Conclusion:Our results demonstrated that both VC and HA had therapeutic effects on tendon healing, especially in the late phase. Level of Evidence I; High quality randomized trial with statistically significant difference.
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