In this article, the mathematical modeling of n-viscoelastic-link robotic manipulators based on the Gibbs-Appell formulation and the assumed mode method is developed. The elastic properties of the links are modeled according to the Timoshenko beam theory and its associated mode shapes. Also the dynamic effects of the motors at the joints are fully taken into consideration. In the mathematical modeling, the effects of torsion, extensional deformation, bending in two directions, structural damping, and viscous air as well as the gravity effects have also been considered. A recursive algorithm based on 4 Â 4 transformation matrices has been developed to ease the derivation of motion equations. The mismatch between the high-speed vibrations of flexible robotic arms and the low-speed operation of the software and hardware interface in the computer and the experimental setup is a serious obstacle for the measuring and controlling of such systems. So, to verify the simulation results and the results obtained from the experimental test bed, high-speed digital-to-analog converter components on an electronic interface board are used in conjunction with the National Instrument's LABVIEW software package.
is paper presents a method for estimating the �exible link's shape by �nite number of sensors. e position and orientation of �exible link are expressed as a function of curvature of the link. An interpolation technique gives this continuous curvature function from a �nite set of the �heatstone bridge made with strain gauges. For interpolation we can use different functions to �nd better way for estimation of link's shape. Comparison between different types of function can show us best corresponding with nature of the link. �ur case study is a single �exible link robot. A high-precision data logger is used as data acquisition instrument.
Utilizing exoskeleton devices to help elderly or empower workers is a growing field of research in robotics. The structure of an exoskeleton can vary depending on user's physical dimensions, joints or muscles targeted for assistance, and maximum achievable actuator torque. In this research, a Human-Model-In-the-Loop (HMIL) constrained optimization technique is proposed to design the RoboWalk lower-limb exoskeleton. RoboWalk is an under-actuated non-anthropomorphic assistive robot, that besides applying the desired assistive force, exerts an undesirable disturbing force leading to the user's fall. The HMIL method uses the augmented human-robot 2D model to take RoboWalk and human body's joint torques into account during optimization. The superiority of HMIL method is proven by comparing the results with other strategies in the literature. Obtained results reveal elimination of the disturbing forces, 2 N.m. reduction in average human knee-joint torque, and significant decrease in the actuator required torque.
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