Dynamic Behavior Of Manipulator Research Articles

Effect of gravity on the dynamic behavior of manipulators

The gravity induced forces on revolute robot links dominate over the dynamic induced forces, particularly at low speeds. This study presents an innovative method to introduce the effect of gravity in the dynamic capability of robot arms. Using the concept of fields, the gravity induced forces acting on individual links are replaced by a single force, called here the generalized weight of the arm. The generalized weight is a force that acts at the end point and its magnitude and direction are functions of the configuration of the arm. Based on the generalized weight field and the generalized inertia tensor introduced by other researchers, the generalized gravitational acceleration field is introduced. This is a vector field whose strength at any point of the work volume indicates the acceleration that is induced on the end effector due to the effect of gravity. The generalized weight and the generalized gravitational acceleration fields are then related to the generalized ellipsoid of inertia and the dynam...

Performance Evaluation of Experimental Device for Space Robot

An experimental system simulating the dynamic behavior of a space manipulator is illustrated in this paper. It is constructed for the purpose of technological demonstration and performance evaluation of space robot. The system consists of a model of space robot having dual manipulators, suspension system, and control system. The model is hung by wire at each joint of the manipulator to cancel the effect of the gravitational force on the ground. The value of wire tension is maintained constant to provide a ground simulation of the dynamic behavior of the manipulator in space. Accelerometers are employed to evaluate the micro-gravity condition for the present experimental device. The dynamics of the twolink manipulator with rigid link is analyzed numerically and experimentally, employing the present facility through the inspection of their dynamic features. In the present paper, the motion of the manipulator is restricted in the vertical plane as the first stage of study. The motion of a free-flying robot is also simulated in the experiment. The results of the numerical simulation and ,the experiment are presented to show the sufficient capability of the ground simulation to study dynamcal behavior of the manipulator in space.

Dynamic modeling of a three degree-of-freedom robotic manipulator

Transfer function models that can provide physical insight into the dynamic behavior of manipulators and establish a foundation for control system analysis and design are identified. Emphasis is directed toward increasing the computational efficiency of the manipulator dynamic equations of motion. A conceptual three-degrees-of-freedom manipulator, which represents state-of-the-art configurations, is designed and simulated on a digital computer. The Lagrangian formulation is applied to develop the complete dynamic equations of motion of the manipulator. The simulation model includes the dynamic interactions of the centrifugal, Coriolis, inertial, and gravitational generalized forces along with the kinematic coupling, and it can accommodate load variations. The simulation model is interfaced to the Steiglitz-McBride identification algorithm to extract, from the complete nonlinear model, simplified linear models that characterize the arm in various regions of the work space. The simplified linear models are second-order discrete-time (input-output) transfer functions.