نوع مقاله : مقاله پژوهشی
نویسنده
استادیار، مهندسی مکانیک، گروه مهندسی مکانیک، دانشکده مهندسی، دانشگاه شهید چمران اهواز، اهواز، خوزستان
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسنده [English]
This paper presents a dynamic model of a robotic manipulator with a time-varying structure in a fluid medium. Changing the working environment of the manipulators and using them as time-varying structure cause to eliminate the robot workspace limitations when used in a fluid medium. In addition, it provides more access for end-effectors via new manipulator structures design that used revolute-prismatic joints. While the new manipulator structure’s model is obtained commensurate with its application in the fluid environment. Thus, by considering the hydrostatic and hydrodynamic interaction forces that implemented between the fluid and the robot arm, the final motion equations of the robot are evaluated. However, the change in the robot’s structure and its fluid implemented action and reaction force, caused the obtained motion equations differ from similar systems with time-invariant structures. As a result, the final equations are time dependent. This is evidenced by comparing the results obtained from the robot's behavior in air and fluid medium. Thus, in addition to the rotational motion, in the linear motion of the prismatic joint, due to the incompressibility of the fluid, a resistive force is applied by the fluid to manipulator links. In this regard, the dynamic model is obtained using the recursive Gibbs-Apple formulation and then simulated in MATLAB software. The equations are simulated and discussed based on the different links cross-sectional areas, various environments, as well as the effect of each of the hydrostatic and hydrodynamic forces. As a result, the robot's motion in the water medium is reduced by 60% relative to the air environment. The robot's motion is more affected by the drag force than other resistive forces.
کلیدواژهها [English]
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