Search results for "Manipulator"
showing 10 items of 47 documents
Sensor Calibration and Registration for Mobile Manipulators
2016
International audience; —This paper describes the methods used to register a mobile manipulator to a workstation to perform assembly tasks. The nonlinear, least square model of the system is formulated and Ceres Solver is used to compute the position of the robot arm relative to the mobile base. The use of non-contact fiducials to test the accuracy and repeatability of the mobile manipulator positioning in the context of an assembly operation is also discussed. Using mathematical methods and indirect measurements it is possible to compute the offset between physical components of the system where direct measurement is not feasible.
Integrated dimensional and drive-train design optimization of a light-weight anthropomorphic arm
2012
An approach to minimize the mass of robotic manipulators is developed by integrated dimensional and drive-train optimization. The method addresses the influences of dimensions and characteristics of drive-trains in the design optimization. Constraints are formulated on the basis of kinematic performance and dynamic requirements, whereas the main objective is to minimize the total mass. Case studies are included to demonstrate the application of the optimization method in the design of assistive robots.
Localization Based on Parallel Robots Kinematics as an Alternative to Trilateration
2022
In this article, a new scheme for range-based localization is proposed. The main goal is to estimate the position of a mobile point based on distance measurements from fixed devices, called anchors, and on inertial measurements. Due to the nonlinear nature of the problem, an analytic relation to compute the position starting from these measurements does not exist, and often trilateration methods are used, generally based on least-square algorithms. The proposed scheme is based on the modeling of the localization process as a parallel robot, thereby methodologies and control algorithms used in the robotic area can be exploited. In particular, a closed-loop control system is designed for trac…
An Application of Iterative Identification and Control in the Robotics Field
2006
The plant model appropriate for designing the control strongly depends on the requirements. Simple models are enough to compute nondemanding controls. The parameters of well-defined structural models of flexible robot manipulators are difficult to determine because their effect is only visible if the manipulator is under strong actions or with high-frequency excitation. Thus, in this chapter, an iterative approach is suggested. This approach is applied to a one-degree-of-freedom flexible robot manipulator, first using some well-known models and then controlling a lab prototype. This approach can be used with a variety of control design and/or identification techniques.
Review on Modeling and Control of Flexible Link Manipulators
2020
This paper presents a review of dynamic modeling techniques and various control schemes to control flexible link manipulators (FLMs) that were studied in recent literature. The advantages and complexities associated with the FLMs are discussed briefly. A survey of the reported studies is carried out based on the method used for modeling link flexibility and obtaining equations of motion of the FLMs. The control techniques are reviewed by classifying them into two main categories: model-based and model-free control schemes. The merits and limitations of different modeling and control methods are highlighted.
Contact Estimation in Robot Interaction
2014
In the paper, safety issues are examined in a scenario in which a robot manipulator and a human perform the same task in the same workspace. During the task execution, the human should be able to physically interact with the robot, and in this case an estimation algorithm for both interaction forces and a contact point is proposed in order to guarantee safety conditions. The method, starting from residual joint torque estimation, allows both direct and adaptive computation of the contact point and force, based on a principle of equivalence of the contact forces. At the same time, all the unintended contacts must be avoided, and a suitable post-collision strategy is considered to move the r…
An adaptive control law for robotic manipulator without velocity feedback
2003
In this paper, a new adaptive control law is designed for robotic manipulators, based on the use of reference velocities instead of the actual ones and feedback signals generated from position errors. The law in question is suitable for trajectory tracking and positioning tasks. Its peculiarities are implementation without velocity measurements and estimation, high signal-to-noise ratio in control torques and absence of parameter drift in positioning tasks. Experimental tests are shown with the aim to confirm the validity of the control law and to illustrate its actual effects on the behaviour of the system.
Mobile Robot and Mobile Manipulator Research Towards ASTM Standards Development
2016
International audience; Performance standards for industrial mobile robots and mobile manipulators (robot arms onboard mobile robots) have only recently begun development. Low cost and standardized measurement techniques are needed to characterize system performance, compare different systems, and to determine if recalibration is required. This paper discusses work at the National Institute of Standards and Technology (NIST) and within the ASTM Committee F45 on Driverless Automatic Guided Industrial Vehicles. This includes standards for both terminology, F45.91, and for navigation performance test methods, F45.02. The paper defines terms that are being considered. Additionally, the paper de…
Tool-Point Control for a Redundant Heave Compensated Hydraulic Manipulator
2012
Abstract In this paper, theoretical and experimental implementation of heave compensation on a redundant hydraulically actuated manipulator with 3-dof has been carried out. The redundancy is solved using the pseudo-inverse Jacobian method. Techniques for minimizing velocities and avoiding mechanical joint saturations is implemented in the null space joint motion. Model based feed-forward, combined with a PI-controller handles the velocity control of each joint. A time domain simulation model has been developed, experimentally verified, and used for controller parameter tuning. Model verification and experimental results are obtained while the manipulator is exposed to wave disturbances crea…
Adaptive interaction robot control with estimation of contact force
2008
Abstract This paper deals with a new adaptive force-position control of a robotic manipulator based on force estimation. First, an adaptive position controller is derived with contact force component as estimated parameters. Second, a supervisory external loop is added in order to regulate the contact force to the desired value. Extensive simulations with 2-DOF manipulator illustrate the followed approach.