Synthesis and Analysis of a Group of 3-Degree-of-Freedom Partially Decoupled Parallel Manipulators

2004 ◽  
Vol 126 (2) ◽  
pp. 301-306 ◽  
Author(s):  
Qiong Jin ◽  
Ting-Li Yang
Keyword(s):  
Topological Structure ◽  
Parallel Manipulators ◽  
Degree Of Freedom ◽  
Parallel Mechanisms ◽  
Kinematics Analysis ◽  
Structural Synthesis ◽  
Real Time Control ◽  
Structure Characteristics ◽  
Time Control ◽  
Internal Relationship

The kinematics decoupling for parallel manipulators is studied in this paper. Based on the topological structure characteristics of parallel mechanisms, the internal relationship between kinematics decoupling and basic kinematics chains is revealed, and the basic principle for structural synthesis of topologically decoupled mechanisms is put forward. Using this theory, a group of 3 degree-of-freedom (DOF) partially decoupled manipulators are synthesized. The expected kinematic outputs of these manipulators are 1-DOF translation and 2-DOF rotation, and motions along or about undesired directions do not exist. The kinematics analysis of a newly synthesized manipulator is discussed and the results indicate that the decoupling property of these architectures makes possible reaching real time control and path planning of parallel manipulators.

A Family of Novel Lower-Mobility Decoupled Parallel Mechanisms

2007 ◽  
Author(s):  
Daxing Zeng ◽  
Sijun Zhu ◽  
Zhen Huang
Keyword(s):  
Real Time ◽  
Basic Feature ◽  
Degree Of Freedom ◽  
Parallel Mechanisms ◽  
Real Time Control ◽  
Motion Feature ◽  
Time Control ◽  
Fixed Base ◽  
Lower Mobility ◽  
Moving Platform

This paper presents a family of novel lower-mobility decoupled parallel mechanisms (DPMs), which consists of one 5-DOF (degree of freedom) DPM, two 4-DOF DPMs, three 3-DOF DPMs, and three 2-DOF DPMs. The basic feature of this family is that the moving platform and the fixed base of the DPMs are connected by two limbs and the motion of the moving platform is fully decoupled. Then the constraint screw method is used to analyze the motion feature of all DPMs presented in this paper. The mobility of these DPMs has also been calculated by the Modified Grubler-Kutzbach criterion. All the DPMs in this paper are simple and no computation is required for real-time control.

scholarly journals A Six Degree-of-Freedom Haptic Device Based on the Orthoglide and a Hybrid Agile Eye

2006 ◽  
Author(s):  
Damien Chablat ◽  
Philippe Wenger
Keyword(s):  
Degrees Of Freedom ◽  
Degree Of Freedom ◽  
Haptic Device ◽  
Parallel Mechanisms ◽  
Real Time Control ◽  
Time Control ◽  
Rotational Motions ◽  
Six Degree Of Freedom ◽  
Rotary Motor ◽  
Three Degrees Of Freedom

This paper is devoted to the kinematic design of a new six degree-of-freedom haptic device using two parallel mechanisms. The first one, called orthoglide, provides the translation motions and the second one, called agile eye, produces the rotational motions. These two motions are decoupled to simplify the direct and inverse kinematics, as it is needed for real-time control. To reduce the inertial load, the motors are fixed on the base and a transmission with two universal joints is used to transmit the rotational motions from the base to the end-effector. Two alternative wrists are proposed (i), the agile eye with three degrees of freedom or (ii) a hybrid wrist made by the assembly of a two-dof agile eye with a rotary motor. The last one is optimized to increase its stiffness and to decrease the number of moving parts.

scholarly journals Type Synthesis of 1T2R Parallel Mechanisms Using Structure Coupling-Reducing Method

2019 ◽  
Vol 32 (1) ◽  
Author(s):  
Haitao Liu ◽  
Ke Xu ◽  
Huiping Shen ◽  
Xianlei Shan ◽  
Tingli Yang
Keyword(s):  
Explicit Form ◽  
Parallel Mechanism ◽  
Analytic Solutions ◽  
Forward Kinematics ◽  
Parallel Mechanisms ◽  
Type Synthesis ◽  
Real Time Control ◽  
Time Control ◽  
Topological Characteristics ◽  
Zero Coupling

Abstract Direct kinematics with analytic solutions is critical to the real-time control of parallel mechanisms. Therefore, the type synthesis of a mechanism having explicit form of forward kinematics has become a topic of interest. Based on this purpose, this paper deals with the type synthesis of 1T2R parallel mechanisms by investigating the topological structure coupling-reducing of the 3UPS&UP parallel mechanism. With the aid of the theory of mechanism topology, the analysis of the topological characteristics of the 3UPS&UP parallel mechanism is presented, which shows that there are highly coupled motions and constraints amongst the limbs of the mechanism. Three methods for structure coupling-reducing of the 3UPS&UP parallel mechanism are proposed, resulting in eight new types of 1T2R parallel mechanisms with one or zero coupling degree. One obtained parallel mechanism is taken as an example to demonstrate that a mechanism with zero coupling degree has an explicit form for forward kinematics. The process of type synthesis is in the order of permutation and combination; therefore, there are no omissions. This method is also applicable to other configurations, and novel topological structures having simple forward kinematics can be obtained from an original mechanism via this method.

scholarly journals A singularity handling algorithm based on operational space control for six-degree-of-freedom anthropomorphic manipulators

2019 ◽  
Vol 16 (3) ◽  
pp. 172988141985891
Author(s):  
Zhi-Hao Kang ◽  
Ching-An Cheng ◽  
Han-Pang Huang
Keyword(s):  
Null Space ◽  
Singularity Analysis ◽  
Degree Of Freedom ◽  
Control Input ◽  
Real Time Control ◽  
Time Control ◽  
Operational Space ◽  
Industrial Manipulators ◽  
Space Motion ◽  
Six Degree Of Freedom

In this article, we analyze the singularities of six-degree-of-freedom anthropomorphic manipulators and design a singularity handling algorithm that can smoothly go through singular regions. We show that the boundary singularity and the internal singularity points of six-degree-of-freedom anthropomorphic manipulators can be identified through a singularity analysis, although they do not possess the nice kinematic decoupling property as six-degree-of-freedom industrial manipulators. Based on this discovery, our algorithm adopts a switching strategy to handle these two cases. For boundary singularities, the algorithm modifies the control input to fold the manipulator back from the singular straight posture. For internal singularities, the algorithm controls the manipulator with null space motion. We show that this strategy allows a manipulator to move within singular regions and back to non-singular regions, so the usable workspace is increased compared with conventional approaches. The proposed algorithm is validated in simulations and real-time control experiments.

A New Parallel Kinematic Machine UPS-2RPS and Kinematics Analysis

2009 ◽  
Vol 626-627 ◽  
pp. 417-422
Author(s):  
Zhi You Feng ◽  
Zhi Guo Gao ◽  
Ting Li Yang ◽  
Ce Zhang
Keyword(s):  
Topological Structure ◽  
Mathematic Model ◽  
Kinematics Analysis ◽  
Parallel Kinematic Machine ◽  
Structure Characteristics ◽  
Parallel Kinematic ◽  
Position Solution

A new parallel kinematic machine UPS-2RPS with serial input limb is presented, the topological structure characteristics are described. The mathematic model of inverse position solution is derived. The workspace of the mechanism is analyzed and researched by results of MATLAB and Pro/E simulation, The research will be of great significance to promote its novation, application and spread .

Static Balancing of Spatial and Planar Parallel Manipulators With Prismatic Actuators

1998 ◽  
Author(s):  
Marc Leblond ◽  
Clément M. Gosselin
Keyword(s):  
Parallel Manipulators ◽  
Geometric Interpretation ◽  
Degree Of Freedom ◽  
Parallel Mechanisms ◽  
Static Balancing ◽  
Inertial Parameters ◽  
Dimensional Parameters ◽  
Balancing Conditions ◽  
Static Conditions ◽  
Planar Parallel Manipulators

Abstract In this paper, the static balancing of existing spatial and planar parallel manipulators by the addition of balancing elements is addressed. Static balancing is defined here as the set of conditions on manipulator dimensional and inertial parameters which, when satisfied, ensure that the weight of the links does not produce any force (or torque) at the actuators for any configuration of the manipulator, under static conditions. These conditions are derived here for spatial six-degree-of-freedom parallel manipulators and it is shown that planar three-degree-of-freedom parallel manipulators can be treated as a particular case of the spatial 6-dof mechanisms. The static balancing conditions associated with planar mechanisms can therefore easily be found, but are not given here because of space limitations. A brief geometric interpretation of the balancing conditions which are associated with statically balanced spatial mechanisms is then carried out. It is shown that balancing is generally possible even when the dimensional parameters are imposed, which is a useful property since dimensional parameters are usually obtained from kinematic design or optimization. Finally, examples of balanced planar and spatial parallel manipulators are given. Static balancing leads to considerable reduction in the actuator forces (or torques), which in turn leads to less powerful actuators and more efficient designs. Moreover, the possibility of balancing existing systems by introducing additional elements, as demonstrated here, is of interest for retrofitting existing parallel mechanisms.

Translational shaking tests achieved on a 6-DOF hydraulic parallel manipulator

2016 ◽  
Vol 43 (1) ◽  
pp. 103-111 ◽  
Author(s):  
Jianjun Yao ◽  
Le Zhang ◽  
Shuo Chen ◽  
Zhenshuai Wan ◽  
Tao Wang ◽  
...  
Keyword(s):  
Parallel Manipulator ◽  
Reference Signal ◽  
Parallel Robots ◽  
Degree Of Freedom ◽  
Real Time Control ◽  
Small Motion ◽  
Content Type ◽  
Time Control ◽  
Xpc Target ◽  
Feed Forward Controller

Purpose – The paper aims to achieve translational shaking tests on a 6-DOF hydraulic parallel manipulator. Shaking tests are commonly performed on shaking tables, which are generally used for small motion ranges and are usually financially costly. The research is required to generate shaking motions in three translational directions for a specimen for shaking tests, but it also needs to produce 6-degree of freedom (DOF) motions with large motion ranges. Design/methodology/approach – A hydraulic 6-DOF (degree of freedom) parallel manipulator is applied to achieve this goal. The link-space control is adopted for the manipulator, and PID controller and feed-forward controller are used for each loop of the system. A hybrid reference signal generator is proposed by using a shaking controller, which is developed to convert the shaking motion into position signal. The converted result is directly added to the pose signal. The whole real-time control system is realized by using MATLAB xPC Target. Findings – The developed method is verified on the hydraulic 6-DOF parallel manipulator with specimen. Experiments show very promising results that the proposed technology is really applicable to perform translational shaking tests on the hydraulic parallel manipulator. Originality/value – A simple yet efficient solution is proposed that allows shaking tests in three translational directions performed on the hydraulic 6-DOF parallel manipulator with wide motion ranges. The paper presents a state-of-the-art related to the applications of parallel robots in several fields of technology.

A General Formula of Degree-of-Freedom for Parallel Manipulators and Its Application

2006 ◽  
Author(s):  
Ting-Li Yang ◽  
Dong-Jin Sun
Keyword(s):  
Characteristic Equation ◽  
Topological Structure ◽  
Topological Analysis ◽  
Parallel Manipulators ◽  
Characteristic Matrix ◽  
Parallel Mechanisms ◽  
Constraint Equations ◽  
Analysis And Synthesis ◽  
Dimension Type ◽  
Symbolic Operation

This paper presents a new DOF formula for mechanism Its main feature is that the calculation of mobility has a single value for a given mechanism without the set of constraint equations, each of parameters in the formula can be correctly determined by simple symbol operation. The formula shows the map relationship between DOF and topological structure of a mechanism. It is embodied in the following aspects: (1) Dimension type: so that topological structure of a mechanism can be represented by symbols. (2) Orientation and location characteristic matrix: so that rank of a mechanism can be calculated by symbolic operation. (3) Orientation and location characteristic equation of serial mechanism and its symbolic operation. (4) Orientation and location characteristic equation of parallel mechanism and its symbolic operation. (5) The DOF calculation based on orientation and location characteristic equations of serial and parallel mechanisms. The DOF formula presented in this paper has already been used for topological analysis and synthesis of parallel mechanisms and its advantages has been proven.

Kinematics Analysis of Some Linear Legs With Different Structures for Limited-DOF Parallel Manipulators

2010 ◽  
Vol 3 (1) ◽  
Author(s):  
Yi Lu ◽  
Bo Hu ◽  
Jianda Han ◽  
Jianping Yu
Keyword(s):  
Angular Velocity ◽  
Parallel Manipulators ◽  
Degree Of Freedom ◽  
Dynamics Analysis ◽  
Kinematics Analysis ◽  
Challenging Issue ◽  
Piston Cylinder ◽  
Limited Degree

To solve the velocity and acceleration of legs with different structures is a fundamental and challenging issue for dynamics analysis of parallel manipulators (PMs). In this paper, the kinematics of linear legs with different structures for limited-degree of freedom (DOF) PMs is studied. First, based on kinematics/statics of general limited-DOF PM, the formulas are derived for solving the angular velocity/acceleration of some linear legs with different structures. Second, the velocity and acceleration of the piston/cylinder in the legs are represented by velocity and acceleration of platform in PM. Finally, the solving procedures are illustrated by applying this approach to a 4DOF PM.

Forward Kinematic Analysis of Kinematically Redundant Hybrid Parallel Robots

2020 ◽  
Vol 12 (6) ◽  
Author(s):  
Kefei Wen ◽  
Clément M. Gosselin
Keyword(s):  
Real Time ◽  
Unique Solution ◽  
Kinematic Analysis ◽  
Parallel Robots ◽  
Degree Of Freedom ◽  
Real Time Control ◽  
The Real ◽  
Time Control ◽  
Forward Kinematic Problem ◽  
Forward Kinematic

Abstract This paper focuses on the forward kinematic analysis of (6 + 3)-degree-of-freedom kinematically redundant hybrid parallel robots. Because all of the singularities are avoidable, the robot can cover a very large orientational workspace. The control of the robot requires the solution of the direct kinematic problem using the actuator encoder data as inputs. Seven different approaches of solving the forward kinematic problem based on different numbers of extra encoders are developed. It is revealed that five of these methods can produce a unique solution analytically or numerically. An example is given to validate the feasibility of these approaches. One of the provided approaches is applied to the real-time control of a prototype of the robot. It is also revealed that the proposed approaches can be applied to other kinematically redundant hybrid parallel robots proposed by the authors.

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