A minimal-error-model based two-step kinematic calibration methodology for redundantly actuated parallel manipulators: An application to a 3-DOF spindle head
TL;DR: A minimal-error-model based two-step kinematic calibration methodology for redundantly actuated parallel manipulators to relieve the influences of zero offsets and geometric source errors.
About: This article is published in Mechanism and Machine Theory.The article was published on 2022-01-01. It has received 12 citations till now. The article focuses on the topics: Kinematics & Calibration.
Citations
More filters
TL;DR: In this article , a geometric error propagation model based accuracy synthesis method for parallel manipulators (PMs) with one translational and two rotational (1T2R) motion abilities is presented.
Abstract:
To meet the increasing requirements for precision hybrid machine tools, this paper presents a geometric error propagation model based accuracy synthesis method for parallel manipulators (PMs) with one translational and two rotational (1T2R) motion abilities. A unified geometric error propagation model of a family of 1T2R PMs is established with the first-order kinematic perturbation method. A set of geometric error propagation intensity indexes is formulated to describe the geometric error propagation characteristics in a quantitative manner. The equivalent effects of specified terminal accuracy are derived to directly determine the allowable values of all geometric source errors. Based on these, a computation algorithm is summarized for designating tolerance allocation scheme to meet the specified terminal accuracy of a 1T2R PM. To demonstrate the accuracy synthesis method, a novel 1T2R PM with a 2UPR-1RPS (‘R’: revolute joint, ‘U’: universal joint, ‘S’: spherical joint, ‘P’: prismatic actuated joint) topology is taken as an example to allocate geometric tolerances under the specified terminal accuracy. Following the tolerance allocation scheme, a laboratory prototype of the exemplary PM is fabricated and further experimentally measured. The measured kinematic results indicate that the prototype possesses an acceptable position error smaller than 0.15mm, verifying the feasibility of the proposed accuracy synthesis method. Hence, the proposed method can be applied as a forward tolerance design tool to reduce the design iterations and development risks of low-mobility parallel robots.
3 citations
TL;DR: In this paper , an adaptive acceleration and deceleration control algorithm is presented to realize the smooth transition between two constrained velocity points, and a spline curve-based interpolation algorithm is proposed to realise the smoothness of the trajectory.
Abstract: Abstract Due to the merits of high rigidity and good dynamics, hybrid machine tools have been gradually applied to efficient machining of thin-walled workpiece with complex geometries. However, the discontinuity of tangential component of toolpath in hybrid machine tools may cause velocity fluctuations, leading to poor surface quality of workpiece. In this paper, a novel 5-axis hybrid machine tool is taken as an example to demonstrate a smooth toolpath interpolation method. First, an adaptive acceleration and deceleration control algorithm is presented to realize the smooth transition between two constrained velocity points. Second, a spline curve-based interpolation algorithm is proposed to realize the smoothness of the trajectory. Meanwhile, a parameter synchronization method is proposed to ensure the synchronization of the interpolated tool-axis vector and the interpolated tool tip. Thirdly, an inverse kinematic analysis is conducted based on an inverse position solution model and a velocity mapping model. Finally, a set of machining tests on S-shape workpiece in line with the ISO standard is carried out to verify the effectiveness of the proposed smooth toolpath interpolation method.
1 citations
TL;DR: In this article , an error modeling method for parallel manipulators with mixed DoF by considering their motion/force transmissibility and constrainability is presented, and the local and global accuracy indices are proposed under the assumption of independent error source bounds and the worst-case principle.
1 citations
References
More filters
881 citations
01 Oct 1987
TL;DR: An overview is given of the existing work on robot calibration, and some of the basic issues are identified in calibration and improvement of robot precision.
Abstract: An overview is given of the existing work on robot calibration, and some of the basic issues are identified in calibration and improvement of robot precision. Modeling, measurement, identification, and correction issues in robot calibration are discussed, and some of the unresolved questions are identified.
545 citations
TL;DR: A rapid customization design prototype system has been developed and applied to the design of a high-speed train’s bogie to illustrate how to construct a product meta-model and how to conduct configuration design on different layers and variant design for generating new products.
Abstract: In order to effectively reuse the design knowledge of product family life cycle development and support holistic and rapid individual product design, this article presents a new meta-model-based sy...
436 citations
TL;DR: In this paper, the Kutzbach-Grubler mobility criterion is used to calculate the degrees of freedom of a general mechanism, but the criterion can break down for mechanisms with special geometries, and in particular, the class of overconstrained parallel mechanisms.
Abstract: The Kutzbach-Grubler mobility criterion calculates the degrees of freedom of a general mechanism. However, the criterion can break down for mechanisms with special geometries, and in particular, the class of so-called overconstrained parallel mechanisms. The problem is that the criterion treats all constraints as active, even redundant constraints, which do not affect the mechanism degrees of freedom. In this paper we reveal a number of screw systems of a parallel mechanism, explore their inter-relationship and develop an original theoretical framework to relate these screw systems to motion and constraints of a parallel mechanism to identify the platform constraints, mechanism constraints and redundant constraints. The screw system characteristics and relationships are investigated for physical properties and a new approach to mobility analysis is proposed based on decompositions of motion and constraint screw systems. New versions of the mobility criterion are thus presented to eliminate the redundant constraints and accurately predict the platform degrees of freedom. Several examples of overconstrained mechanisms from the literature illustrate the results.
372 citations
TL;DR: A general method to estimate the link parameter errors for any serial link manipulator (i.e., n links, and any combination of revolute and prismatic joints) through a linear kinematic model.
Abstract: The absolute positioning accuracy of robot manipulator can be increased substantially by updating the nominal link parameters in the control software. This paper presents a general method to estimate the link parameter errors for any serial link manipulator (i.e., n links, and any combination of revolute and prismatic joints). The parameters are estimated through a linear kinematic model which relates the link bias errors to the end-effector positioning error. Only end-effector measurements are required instead of individual link measurements to implement this method.
293 citations