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In this paper, a new method for the estimation of orientation repeatability index is proposed for industrial manipulator robots. First, we compute orientation repeatability in different locations of the workspace using the experimental covariance matrix and the stochastic ellipsoid modeling. Then we display experimental results about the direct measurement of orientation repeatability for an industrial...
The common problem of multi d.o.f. positioning or multi - component sensing devices based on compliant mechanisms is to reach the best accuracy of the positioning / sensing systems. This paper deals with analysis of elastic parts / segments of structures and possible errors due to cross compliance effects. The model that enables to minimize compliance errors and calibration procedure is discussed.
In state of the art robotics, high positioning accuracy is achieved by using solid and stiff components as well as powerful drive units which have no backlash. In contrast, human beings are able to achieve remarkable high positioning accuracy despite of low mass, low power consumption and relatively simple mechanics. One approach to obtain this accuracy is to temporarily create additional supporting...
This paper presents the construction of a realistic linear parameter-varying (LPV) model of a robotic manipulator using parameter set mapping, for the purpose of synthesizing an LPV gain-scheduled controller. A nonlinear dynamic model of the manipulator is obtained and a quasi-LPV model is derived. Since the quasi-LPV model has a large number of affine scheduling parameters and a large overbounding,...
This paper discusses the absolute positioning accuracy of a medical robotic system for minimally invasive spine surgery (MISS). First, the system architecture and main working flow are briefly introduced. Then, according to the requirement of MISS operation, a five-degree-of-freedom (5-DOF) operating mechanism is designed and developed for such applications, and a detailed analysis has been performed...
This paper presents a novel 3-DOF precision positioning stage for nanoimprint lithograph (NIL). Due to the advantages such as high positioning accuracy, dexterity, low inertial, and balanced mechanical structure, a piezo-driven flexure-based parallel mechanism is utilized. Based on Pseudo-Rigid-Body modelling theory, the kinematics of the stage is developed by simplifying the single-axis flexure hinges...
In recent years, parallel robots find many applications in human-systems interaction, medical robots, rehabilitation, exoskeletons, to name a few. These applications are characterized by many imperatives, with robust precision and dynamic workspace computation as the two ultimate ones. Practical methods of kinematic's calibration make use of the linear differential error of the kinematics' model....
This paper presents a novel underwater movement compensation algorithm for stabilization of manipulator position utilizing not ROV movements for disturbance compensation, but overlaid manipulator movements. A model based estimator is used to predict vehicle movement and provide the manipulation system with the necessary time to compensate for the estimated motion. It describes the conceptual benefits...
Stewart platform used in testing system for two spacecraftpsilas motion docking mechanism requires high accuracy to achieve better simulation result. In this paper, an accuracy synthesis of the Stewart platform used in a testing system for spacecraft docking mechanism is presented. The method is based on the error model formed through differentiation of the kinematics equations of the platform and...
This paper presents a novel macro/micro 3-DOF parallel platform for micro/nano positioning applications. The kinematics model of the dual parallel mechanism system is established via the stiffness model of individual wide-range flexure hinge and vector-loop equation. The inverse kinematics is analyzed and simulated on a parallel mechanism with real parameters. Whereafter, the reachable and usable...
The present paper introduces an evaluation of the manipulation performance of a cooperating robotic manipulator with respect to task accuracy, taking into consideration the effects of the dynamic process between inputs and outputs in the manipulation system. A measure based on the output controllability of the manipulation system is proposed, which shows the relationship between the object's position...
We aim to design a mechanism with high acceleration and high accuracy. Force redundant mechanism is designed to realize these requirements. However, big excessive internal forces will arise if all the joints adopt position control scheme for upper controller and velocity control scheme for servo motor to achieve a high accuracy. Therefore, an idea of introducing kinematic redundancy into force redundant...
Kinematic calibration is an effective and economical way to improve the accuracy of the parallel robot. A new calibration method using an orientation constraint is presented in this paper. The main idea is to keep two attitude angles of the end-effector constant at different measurement configurations with the help of a commercial biaxial inclinometer. Repeatability and resolution of the inclinometer...
This paper studies the use of neural networks in robotic position/orientation control. The process is divided into two tasks, i.e., the inverse kinematics solution and the adaptive motor control. Simulation results of a three-link robotic arm in a two-dimensional workspace demonstrate the validity of the design. The hierarchal nature of the design allows it to be applied to more complicated systems...
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