Application of Counter-Rotary Counterweights to the Dynamic Balancing of a Spatial Parallel Manipulator

2012 ◽  
Vol 162 ◽  
pp. 224-233 ◽  
Author(s):  
Mario Acevedo ◽  
Marco Ceccarelli ◽  
Giuseppe Carbone
Keyword(s):  
Dynamic Simulation ◽  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Dynamic Balance ◽  
General Purpose ◽  
Dynamic Balancing ◽  
Second Stage ◽  
Fixed Base ◽  
Moving Platform ◽  
Multi Body

The dynamic balancing of a spatial parallel manipulator of three degrees-of-freedom, CaPaMan-2 (Cassino Parallel Manipulator 2), by the application of Counter-Rotary Counterweights (CRCW) is analyzed. To accomplish this objective the mass and inertia of the moving platform are dynamically replaced by point masses located at the points of attachment of the legs to the platform and the mechanism is balanced by considering each of the legs independently. This fully parallel manipulator has three identical legs, each one composed by a four-bar mechanism (an articulated parallelogram) connected to the fixed base, and a link supported by the coupler that connects to the mobile platform. This link, seen as a pendulum, is transformed to a dynamic balancer using a Counter-Rotary Counterweight in order to compensate the motion of the moving platform. In a second stage the articulated parallelogram is modified by adding Counter-Rotary Counterweight plus a Counterweight to dynamic balance its part of the system. As a final result it is obtained a new design, with a parallel manipulator dynamic balanced. The resulting model of the manipulator is validated by dynamic simulation, using general purpose software for the analysis and dynamic simulation of multi-body systems (ADAMS).

Design Optimization of a Cartesian Parallel Manipulator

2003 ◽  
Vol 125 (1) ◽  
pp. 43-51 ◽  
Author(s):  
Han Sung Kim ◽  
Lung-Wen Tsai
Keyword(s):  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Bending Moment ◽  
Revolute Joints ◽  
Fixed Base ◽  
Moving Platform ◽  
Linear Actuators ◽  
External Forces ◽  
Limb Structure ◽  
Actuation Method

This paper introduces a 3-DOF translational parallel manipulator called Cartesian Parallel Manipulator (CPM). The manipulator consists of a moving platform that is connected to a fixed base by three limbs. Each limb is made up of one prismatic and three revolute joints and all joint axes are parallel to one another. In this way, each limb provides two rotational constraints to the moving platform and the combined effects of the three limbs lead to an over-constrained mechanism with three translational degrees of freedom. The manipulator behaves like a conventional X-Y-Z Cartesian machine due to the orthogonal arrangement of the three limbs. Two actuation methods are analyzed. However, the rotary actuation method is discarded because of the existence of singularities within the workspace. For the linear actuation method, there exists a one-to-one correspondence between the input and output displacements of the manipulator. The effects of misalignment of linear actuators on the motion of the moving platform are discussed. Each limb structure is exposed to a bending moment induced by external forces exerted on the moving platform. In order to minimize the deflection at the joints caused by the bending moment, a method to maximize the stiffness is suggested. A numerical example of the optimal design is presented.

Dynamic Modeling of a Parallel Manipulator With Three Translational Degrees of Freedom

1998 ◽  
Author(s):  
Richard Stamper ◽  
Lung-Wen Tsai
Keyword(s):  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Close Agreement ◽  
Jacobian Matrix ◽  
Parallel Manipulators ◽  
Kinematic Structure ◽  
End Effector ◽  
Moving Platform ◽  
Euler Approach ◽  
Computationally Intensive

Abstract The dynamics of a parallel manipulator with three translational degrees of freedom are considered. Two models are developed to characterize the dynamics of the manipulator. The first is a traditional Lagrangian based model, and is presented to provide a basis of comparison for the second approach. The second model is based on a simplified Newton-Euler formulation. This method takes advantage of the kinematic structure of this type of parallel manipulator that allows the actuators to be mounted directly on the base. Accordingly, the dynamics of the manipulator is dominated by the mass of the moving platform, end-effector, and payload rather than the mass of the actuators. This paper suggests a new method to approach the dynamics of parallel manipulators that takes advantage of this characteristic. Using this method the forces that define the motion of moving platform are mapped to the actuators using the Jacobian matrix, allowing a simplified Newton-Euler approach to be applied. This second method offers the advantage of characterizing the dynamics of the manipulator nearly as well as the Lagrangian approach while being less computationally intensive. A numerical example is presented to illustrate the close agreement between the two models.

scholarly journals Research on Dynamic Balance Adjustment Method of Single Braced Frame Gyroscope Rotor

2019 ◽  
Vol 256 ◽  
pp. 02005
Author(s):  
Xukui Hou ◽  
Ende Wang ◽  
Hui Cao ◽  
Yalong Zhu ◽  
Kai Qi
Keyword(s):  
Mass Distribution ◽  
Degrees Of Freedom ◽  
Dynamic Balance ◽  
Dynamic Balancing ◽  
Braced Frame ◽  
Rigid Connection ◽  
Rotational Degrees Of Freedom ◽  
Vibration Rotation ◽  
Rotor Mass ◽  
Rotation Component

The uneven mass distribution of gyro rotors results in vibration, rotation and drift of gyro rotors, which seriously affect the performance index and life of gyro rotors. However, because there is no rigid connection between the rotary shaft and the shell of the gyro rotor, the dynamic balancing machine can only balance the vibration component of the single braced frame gyroscope rotor, and can’t measure the gyro rotor’s rotation component. By analyzing the influence of uneven rotor mass distribution on the gyro rotor performance, a method of eliminating two rotational degrees of freedom of the gimbal in gyro rotor by mandrel is proposed, which makes the dynamic balancing machine directly measure the vibration component and the moving component of the gyroscope rotor, and simplifies the dynamic balancing debugging process.

Kinematic Synthesis of a Spatial 3-RPS Parallel Manipulator

2003 ◽  
Vol 125 (1) ◽  
pp. 92-97 ◽  
Author(s):  
Han Sung Kim ◽  
Lung-Wen Tsai
Keyword(s):  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Parallel Manipulators ◽  
Point Of View ◽  
Dimensional Synthesis ◽  
Kinematic Synthesis ◽  
End Effector ◽  
Solution Methods ◽  
Moving Platform ◽  
At Will

This paper presents the design of spatial 3-RPS parallel manipulators from dimensional synthesis point of view. Since a spatial 3-RPS manipulator has only 3 degrees of freedom, its end effector cannot be positioned arbitrarily in space. It is shown that at most six positions and orientations of the moving platform can be prescribed at will and, given six prescribed positions, there are at most ten RPS chains that can be used to construct up to 120 manipulators. Further, solution methods for fewer than six prescribed positions are also described.

A 2(3-RRPS) parallel manipulator inspired by Gough–Stewart platform

Robotica ◽  
2012 ◽  
Vol 31 (3) ◽  
pp. 381-388 ◽  
Author(s):  
Jaime Gallardo-Alvarado ◽  
Mario A. García-Murillo ◽  
Eduardo Castillo-Castaneda
Keyword(s):  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Screw Theory ◽  
Parallel Manipulators ◽  
Forward Kinematics ◽  
Triangular Prism ◽  
Input Output ◽  
Six Degrees Of Freedom ◽  
Moving Platform

SUMMARYThis study addresses the kinematics of a six-degrees-of-freedom parallel manipulator whose moving platform is a regular triangular prism. The moving and fixed platforms are connected to each other by means of two identical parallel manipulators. Simple forward kinematics and reduced singular regions are the main benefits offered by the proposed parallel manipulator. The Input–Output equations of velocity and acceleration are systematically obtained by resorting to reciprocal-screw theory. A case study, which is verified with the aid of commercially available software, is included with the purpose to exemplify the application of the method of kinematic analysis.

Workspace Optimization of a Six Degrees of Freedom Parallel Manipulator for Micromachining

2010 ◽  
Author(s):  
Ahmet Agaoglu ◽  
Namik Ciblak ◽  
Koray K. Safak
Keyword(s):  
Numerical Analysis ◽  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Base Plane ◽  
Six Degrees Of Freedom ◽  
Moving Platform ◽  
Workspace Optimization ◽  
Kinematic Diagram ◽  
Orientation Workspace

This work addresses the optimization of the workspace of a six degrees of freedom parallel manipulator. In this study, The topology of the manipulator is composed of three xy-tables, symmetrically positioned on a circle on a base plane, connected by three legs to a moving platform. Kinematic composition of the manipulator is introduced and kinematic diagram is illustrated. Orientation workspace is investigated using three different orientation representations. XYZ fixed angles representation is selected considering the benefits of its visualization are considered. By using this representation, the orientation workspace is modeled and kinematic circuits of the manipulator are explored. First, optimization is performed without slider limitations. A result table is obtained based on the user defined parameters. Secondly, optimization is performed under slider limitations. The maximal orientation capability is optimized using numerical analysis. The optimized configuration of the manipulator indicates that a 330% increase in orientation capability is achieved, compared to the old configuration.

Orientation Workspace Analysis of a Novel 3SPS+1PS Symmetrical Parallel Manipulator Based on Unit Quaternion

2011 ◽  
Vol 201-203 ◽  
pp. 1849-1853
Author(s):  
Jing Li Yu ◽  
Gang Cheng ◽  
Shuai Zhang ◽  
De Kun Zhang
Keyword(s):  
Inverse Kinematics ◽  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Unit Quaternion ◽  
Structure Characteristics ◽  
Workspace Analysis ◽  
Moving Platform ◽  
Position And Orientation ◽  
4 Degrees Of Freedom ◽  
Orientation Workspace

For a novel 3SPS+1PS parallel manipulator with 4 degrees of freedom including three rotations and one translation, the formulae for solving the inverse kinematics equations are derived based on quaternion method. Unit quaternion is used to represent the position and orientation of moving platform, and the singularities caused by Euler angles are avoided. Combining the topological structure characteristics of the parallel manipulator, it only has three rotations when its moving platform is at a given translation position. Based on the inverse position/pose equations and the all the constraints of the parallel manipulator, the discrete algorithm for the orientation workspaces of 3SPS+1PS parallel manipulator where the moving platform is at some different given translation positions are designed. The research builds the theoretical basis for optimizing the orientation workspace with given position.

A Parallel 5 DOF Positioner for Semi-Spherical Workspaces

2004 ◽  
Author(s):  
Benjamin Maurin ◽  
Bernard Bayle ◽  
Jacques Gangloff ◽  
Michel de Mathelin ◽  
Olivier Piccin
Keyword(s):  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Medical Applications ◽  
Robotic Device ◽  
X Ray ◽  
Revolute Joints ◽  
X Ray Imaging ◽  
Physical Prototype ◽  
Moving Platform ◽  
Functional Point

In this paper, a new five-degree-of-freedom parallel manipulator is described and modeled. This structure has been specially designed for medical applications that require in the same time mobility, compactness and accuracy around a functional point. The purpose of this robotic device is to help practitioners to perform accurate needle insertions while preserving them from harmful intra-operative X-ray imaging devices. The system is built from revolute joints, among which only five joints are actuated to convey the required five degrees of freedom to its moving platform. A numerical simulation of the workspace and a physical prototype are presented.

A novel class of generalized parallel manipulators with high rotational capability

2020 ◽  
Vol 234 (23) ◽  
pp. 4599-4619
Author(s):  
Chunxu Tian ◽  
Dan Zhang ◽  
Jian Liu
Keyword(s):  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Structural Characteristics ◽  
Synthesis Method ◽  
Parallel Manipulators ◽  
Rigid Bodies ◽  
Kinematic Chains ◽  
Moving Platforms ◽  
Moving Platform ◽  
Limb Structure

A conventional parallel manipulator is characterized by connecting one moving platform with two or more serial kinematic limbs. Since each limb is independently supporting one moving platform, the moving platform must be a rigid body with several kinematic pairs fixed on it. However, for generalized parallel manipulators with articulated moving platforms, the moving platforms are not limited to rigid bodies but including serial kinematic chains or internal kinematic joints. The introduction of articulated moving platforms allows for improving the kinematic performance of generalized parallel manipulators, especially for rotational capability. On account of the structural characteristics of the moving platforms, it also poses a significant challenge in the construction of the structures of manipulators. This research raises a new method for the type synthesis of generalized parallel manipulators with novel articulated moving platforms. The proposed method introduces a striking shortcut for the limb structure analysis of mechanisms with high rotational capability. In this paper, a class of generalized parallel manipulator with different degrees of freedom from 3 to 6 are constructed by using the constraint synthesis method, and several examples are provided to demonstrate the feasibility of the advocated method. At last, the 3T3R generalized parallel manipulator is taken as an example to analyze the inverse kinematics, and the evaluation of the workspace is conducted to verify the rotational capacity.

Design and Analysis of a Sliding Panel Shape Morphing Mechanism System

2016 ◽  
Author(s):  
Aaron Yu ◽  
Fengfeng (Jeff) Xi
Keyword(s):  
Degrees Of Freedom ◽  
Longitudinal Direction ◽  
General Purpose ◽  
Search Method ◽  
Application System ◽  
Driving System ◽  
Six Degrees Of Freedom ◽  
Shape Morphing ◽  
Different Shapes ◽  
Moving Platform

A sliding panel shape morphing mechanism system is proposed. The said system is constructed by a number of segmented rigid panels that are allowed to slide relative to each other during shape morphing. In this paper, a method is presented for the design and analysis of the said system using a hexapod as a general-purpose driving system with six degrees-of-freedom. First, it is shown that a proper passive linkage system is required to connect a set of sliding panels to the base and moving platform of the hexapod. Each panel is made of a telescopic pair in the longitudinal direction and connected transversally with two adjacent panels through slots. Second, after modeling the entire system and formulating the constraints among the sliding panels, a search method is presented to determine the solutions that all the sliding panels can move without interference under a given hexapod motion. Further studies are also carried out to examine different shapes of the base and moving platform as well as different number of panels that can approximate a real application system, such as a morphing wing.

Sign in / Sign up

Export Citation Format

Share Document