Static Balancing of a Parallel Kinematics Machine With Linear-Delta Architecture

2014 ◽  
Author(s):  
Alberto Martini ◽  
Marco Troncossi ◽  
Marco Carricato ◽  
Alessandro Rivola
Keyword(s):  
General Theory ◽  
Closed Loop ◽  
Parallel Robot ◽  
Design Solution ◽  
Robot Design ◽  
Gravity Compensation ◽  
Parallel Kinematics ◽  
Static Balancing ◽  
Milling Operation ◽  
Working Performance

The study deals with the compensation of gravity loads in closed-loop mechanisms as a possible strategy for enhancing their working performance. This work focuses on the Orthoglide 5-axis, a prototypal parallel robot for milling operation, characterized by linear-delta architecture with two further serial DOFs. Starting from a general theory formerly proposed by the authors, gravity compensation of the mechanism is analytically carried out. The statically balanced Orthoglide 5-axis can be obtained by installing on one leg a proper set of extension springs and a simple additional linkage. A feasible design solution for developing the device in practice is presented. The proposed balancing device can be implemented with minor modifications of the original robot design, thus appearing a profitable solution to be possibly extended to other machinery with similar architecture.

Singularity Analysis of a Novel 4-DOFs Parallel Robot H4 by Using Screw Theory

2003 ◽  
Author(s):  
Hee-Byoung Choi ◽  
Atsushi Konno ◽  
Masaru Uchiyama
Keyword(s):  
Closed Loop ◽  
Jacobian Matrix ◽  
Screw Theory ◽  
Parallel Robot ◽  
Singularity Analysis ◽  
Loop Structure ◽  
Singular Configurations ◽  
Planning And Control ◽  
Kinematic Singularities ◽  
And Control

The closed-loop structure of a parallel robot results in complex kinematic singularities in the workspace. Singularity analysis become important in design, motion, planning, and control of parallel robot. The traditional method to determine a singular configurations is to find the determinant of the Jacobian matrix. However, the Jacobian matrix of a parallel manipulator is complex in general, and thus it is not easy to find the determinant of the Jacobian matrix. In this paper, we focus on the singularity analysis of a novel 4-DOFs parallel robot H4 based on screw theory. Two types singularities, i.e., the forward and inverse singularities, have been identified.

scholarly journals The Design of a Novel Prismatic Drive for a Three-DOF Parallel-Kinematics Machine

2005 ◽  
Vol 128 (4) ◽  
pp. 710-718 ◽  
Author(s):  
D. Chablat ◽  
J. Angeles
Keyword(s):  
Parallel Robot ◽  
Rolling Motion ◽  
Parallel Kinematics ◽  
Cam Mechanism ◽  
Pure Rolling ◽  
Parallel Kinematics Machines

The design of a novel prismatic drive is reported in this paper. This transmission is based on Slide-o-Cam, a cam mechanism with multiple rollers mounted on a common translating follower. The design of Slide-o-Cam was reported elsewhere. This drive thus provides pure-rolling motion, thereby reducing the friction of rack-and-pinions and linear drives. Such properties can be used to design new transmissions for parallel-kinematics machines. In this paper, this transmission is intended to replace the ball-screws in Orthoglide, a three-dof parallel robot intended for machining applications.

scholarly journals Kinematic Analysis and Verification of a New 5-DOF Parallel Mechanism

2021 ◽  
Vol 11 (17) ◽  
pp. 8157
Author(s):  
Yesong Wang ◽  
Changhuai Lyu ◽  
Jiang Liu
Keyword(s):  
Parallel Mechanism ◽  
Closed Loop ◽  
Three Dimensional ◽  
Line Geometry ◽  
Vector Method ◽  
Five Dimensions ◽  
Grassmann Line Geometry ◽  
Working Performance ◽  
Geometry Method ◽  
Unstable Problem

This paper first designs a new 5-DOF parallel mechanism with 5PUS-UPU, and then analyses its DOF by traditional Grubler–Kutzbach and motion spiral theory. It theoretically shows that the mechanism meets the requirement of five dimensions of freedoms including three-dimensional movement and two-dimensional rotation. Based on this, the real mechanism is built, but unfortunately it is found unstable in some positions. Grassmann line geometry method is applied to analyze its unstable problem caused by singular posture, and then an improving method is put forward to solve it. With the improved mechanism, closed loop vector method is employed to establish the inverse position equation of the parallel mechanism, and kinematics analysis is carried out to get the mapping relationships between position, speed, and acceleration of moving and fixed platform. Monte Carlo method is used to analyze the workspace of the mechanism, to explore the influencing factors of workspace, and then to get the better workspace. Finally, an experiment is designed to verify the mechanism working performance.

Experiments on Linear and Nonlinear Control of a Multi-DOF Parallel Mechanism

2003 ◽  
Author(s):  
Sandor Riebe ◽  
Heinz Ulbrich
Keyword(s):  
Degrees Of Freedom ◽  
Motion Tracking ◽  
Parallel Robot ◽  
Parallel Kinematics ◽  
Control Laws ◽  
Six Degrees Of Freedom ◽  
Position Accuracy ◽  
Nonlinear Approach ◽  
Linear Approach ◽  
Measurement Results

Parallel kinematics with multi degrees-of-freedom (DOF), like hexapod-systems, are mostly used in applications where high demands on position accuracy are required and/or high accelerations are needed. Adequate control concepts are essential in order to achieve the desired dynamic response. This paper deals with a comparative study of two structural different control concepts applied on a parallel robot with six degrees-of-freedom. The first one is a decentral linear approach and the second one is a multivariable nonlinear approach. The two concepts are presented and implemented on an experimental hexapod-system. In order to verify the used dynamic model comparisons between simulation and measurement results are shown. Finally, experiments have been carried out to compare the control laws with respect to their motion tracking performance.

Sign in / Sign up

Export Citation Format

Share Document