Workspace Analysis and Dimensional Synthesis on a Delta Parallel Mechanism with Branch Chain Offset

2012 ◽  
Vol 152-154 ◽  
pp. 1526-1532
Author(s):  
Chen Chen Huang ◽  
Lin Yong Shen ◽  
Jin Wu Qian ◽  
Yan An Zhang
Keyword(s):  
Cross Section ◽  
Inverse Kinematics ◽  
Force Feedback ◽  
Dimensional Synthesis ◽  
Open Chain ◽  
Vector Method ◽  
Workspace Analysis ◽  
Matrix Condition Number ◽  
A Chain ◽  
Matrix Condition

In this paper, we intend to design a force-feedback device that meets the requirements in workspace. First, based on the modified Delta mechanism, we introduced a chain offset angle that is defined as alpha. We established the positive and inverse kinematics model by the vector method. According to the inverse kinematics formula, envelope body equation of single-open-chain subspace was deduced. We drew the geometric shape of the subspace under three situations while L1 was more than or equal to or less than L2. Then the influence of alpha on the whole workspace and mechanism size is deeply discussed. The cross section view of the space was also plotted by MATLAB. Finally, we gave an example using the Jacobin matrix condition number as the mechanism performance index for dimensional synthesis. The results show that the workspace meets the requirements well.

Thumb Configuration and Performance Evaluation for Dexterous Robotic Hand Design

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Hairong Wang ◽  
Shaowei Fan ◽  
Hong Liu
Keyword(s):  
Performance Evaluation ◽  
Inverse Kinematics ◽  
Evaluation Method ◽  
Jacobian Matrix ◽  
Robotic Hand ◽  
Matrix Condition Number ◽  
Acceleration Analysis ◽  
Performance Evaluation Method ◽  
And Performance ◽  
Matrix Condition

The force and/or motion transmissibility and the analyticity of inverse kinematics for a thumb mechanism depend on thumb configuration. This paper presents a general framework for the thumb configuration and performance evaluation in the design of dexterous robotic hand. The thumb configuration is described by the functional analysis of human thumb, and the thumb of robotic hand is generalized into 15 configurations. A performance evaluation method is proposed based on kinetostatic and dynamic dexterity as well as workspace. The kinetostatic dexterity is based on a Jacobian matrix condition number (JMCN). A dynamic dexterity measure is presented via acceleration analysis, which keeps a clear geometric meaning. The proposed method is applied to evaluate the performance of three examples, which cover thumb configurations of most existing dexterous hands. Performance evaluation results demonstrate the effectiveness of the proposed method. Using these results and the proposed performance evaluation method, meaningful design principles are presented to guide the design of the thumb configuration.

Design, Modeling and Kinematics Analysis of a Novel Serial/Parallel Pole Climbing and Manipulating Robot

Volume 2 ◽  
2004 ◽  
Author(s):  
G. R. Vossoughi ◽  
S. Bagheri ◽  
M. Tavakoli ◽  
M. R. Zakerzadeh ◽  
M. Hosseinzadeh
Keyword(s):  
Cross Section ◽  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Main Part ◽  
Target Point ◽  
Tubular Structures ◽  
Kinematics Analysis ◽  
Kinematics Model ◽  
Workspace Analysis ◽  
Forward And Inverse Kinematics

This paper introduces a multi-task 4 DOF pole climbing/manipulating robotic mechanism. A hybrid serial/parallel mechanism, providing 2 translations and 2 rotations, have been designed as the main part of the mechanism. This robotic mechanism can travel along tubular structures with bends, branches and step changes in cross section. It is also able to perform manipulation, repair and maintenance tasks after reaching the target point on the structure. After introducing the mechanism, a kinematics model and the forward and inverse kinematics as well as the workspace analysis of the mechanism are presented.

Kinematic Analysis and Optimization of a Novel Robot for Surgical Tool Manipulation

2008 ◽  
Author(s):  
Xiaoli Zhang ◽  
Carl A. Nelson
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Force Feedback ◽  
Robotic Systems ◽  
Small Space ◽  
Surgical Robots ◽  
Tool Positioning ◽  
Rotation Axes ◽  
Surgical Tool ◽  
Linear Nature

The size and limited dexterity of current surgical robotic systems are factors which limit their usefulness. To improve the level of assimilation of surgical robots in minimally invasive surgery (MIS), a compact, lightweight surgical robotic positioning mechanism with four degrees of freedom (DOF) (three rotational DOF and one translation DOF) is proposed in this paper. This spatial mechanism based on a bevel-gear wrist is remotely driven with three rotation axes intersecting at a remote rotation center (the MIS entry port). Forward and inverse kinematics are derived, and these are used for optimizing the mechanism structure given workspace requirements. By evaluating different spherical geared configurations with various link angles and pitch angles, an optimal design is achieved which performs surgical tool positioning throughout the desired kinematic workspace while occupying a small space bounded by a hemisphere of radius 13.7 cm. This optimized workspace conservatively accounts for collision avoidance between patient and robot or internally between the robot links. This resultant mechanism is highly compact and yet has the dexterity to cover the extended workspace typically required in telesurgery. It can also be used for tool tracking and skills assessment. Due to the linear nature of the gearing relationships, it may also be well suited for implementing force feedback for telesurgery.

Workspace, dexterity and dimensional optimization of microhexapod

2015 ◽  
Vol 35 (4) ◽  
pp. 341-347 ◽  
Author(s):  
E. Rouhani ◽  
M. J. Nategh
Keyword(s):  
Degrees Of Freedom ◽  
Optimization Problem ◽  
Screw Theory ◽  
Design Parameters ◽  
Dimensional Synthesis ◽  
Content Type ◽  
Workspace Analysis ◽  
The Difference ◽  
Flexure Joints ◽  
6 Degrees Of Freedom

Purpose – The purpose of this paper is to study the workspace and dexterity of a microhexapod which is a 6-degrees of freedom (DOF) parallel compliant manipulator, and also to investigate its dimensional synthesis to maximize the workspace and the global dexterity index at the same time. Microassembly is so essential in the current industry for manufacturing complicated structures. Most of the micromanipulators suffer from their restricted workspace because of using flexure joints compared to the conventional ones. In addition, the controllability of micromanipulators inside the whole workspace is very vital. Thus, it is very important to select the design parameters in a way that not only maximize the workspace but also its global dexterity index. Design/methodology/approach – Microassembly is so essential in the current industry for manufacturing complicated structures. Most of the micromanipulators suffer from their restricted workspace because of using flexure joints compared to the conventional ones. In addition, the controllability of micromanipulators inside the whole workspace is very vital. Thus, it is very important to select the design parameters in a way that not only maximize the workspace but also its global dexterity index. Findings – It has been shown that the proposed procedure for the workspace calculation can considerably speed the required calculations. The optimization results show that a converged-diverged configuration of pods and an increase in the difference between the moving and the stationary platforms’ radii cause the global dexterity index to increase and the workspace to decrease. Originality/value – The proposed algorithm for the workspace analysis is very important, especially when it is an objective function of an optimization problem based on the search method. In addition, using screw theory can simply construct the homogeneous Jacobian matrix. The proposed methodology can be used for any other micromanipulator.

The Design of a Chain of Spherical Stephenson Mechanisms for a Gearless Robotic Pitch-Roll Wrist

2005 ◽  
Vol 128 (2) ◽  
pp. 422-429 ◽  
Author(s):  
S. Hernandez ◽  
S. Bai ◽  
J. Angeles
Keyword(s):  
Unmodeled Dynamics ◽  
Manufacturing Cost ◽  
Interference Avoidance ◽  
Dimensional Synthesis ◽  
Bevel Gears ◽  
Industrial Manipulators ◽  
Differential Mechanism ◽  
Gear Trains ◽  
Robot Performance ◽  
A Chain

Although bevel-gear robotic wrists are widely used in industrial manipulators due to their simple kinematics and low manufacturing cost, their gear trains function under rolling and sliding, the latter bringing about noise and vibration. Sliding is inherent to the straight teeth of the bevel gears of these trains. Moreover, unavoidable backlash introduces unmodeled dynamics, which mars robot performance. To alleviate these drawbacks, a gearless pitch-roll wrist is currently under development for low backlash and high stiffness. The wrist consists of spherical cam-rollers and spherical Stephenson linkages, besides two roller-carrying disks that drive a combination of cams and Stephenson mechanisms, the whole system rotating as a differential mechanism. The paper focuses on the design of the chain of spherical Stephenson mechanisms. The problem of the dimensional synthesis is addressed, and interference avoidance is discussed. An embodiment of the concept is also included.

Approximate Motion Synthesis of Open and Closed Chains via Parametric Constraint Manifold Fitting: Preliminary Results

2003 ◽  
Author(s):  
Pierre M. Larochelle
Keyword(s):  
Optimization Techniques ◽  
Robotic Systems ◽  
Dimensional Synthesis ◽  
Motion Synthesis ◽  
Open Chain ◽  
Constraint Manifold ◽  
Synthesis Technique ◽  
Numerical Design ◽  
Design Case ◽  
Parametric Constraint

In this paper we present a novel dyad dimensional synthesis technique for approximate motion synthesis. The methodology utilizes an analytic representation of the dyad’s constraint manifold that is parameterized by its dimensional synthesis variables. Nonlinear optimization techniques are then employed to minimize the distance from the dyad’s constraint manifold to a finite number of desired locations of the workpiece. The result is an approximate motion dimensional synthesis technique that is applicable to planar, spherical, and spatial dyads. Here, we specifically address the planar RR, spherical RR and spatial CC dyads since these are often found in the kinematic structure of robotic systems and mechanisms. These dyads may be combined serially to form a complex open chain (e.g. a robot) or when connected back to the fixed link they may be joined so as to form one or more closed chains (e.g. a linkage, a parallel mechanism, or a platform). Finally, we present some initial numerical design case studies that demonstrate the utility of the synthesis technique.

Design, Synthesis and Experiment of Foot-driven Lower Limb Rehabilitation Mechanisms

2021 ◽  
pp. 1-44
Author(s):  
Chennan Yu ◽  
Jun Ye ◽  
Jiangming Jia ◽  
Xiong Zhao ◽  
Zhiwei Chen ◽  
...  
Keyword(s):  
Ankle Joint ◽  
Lower Limb ◽  
Gear Train ◽  
Home Healthcare ◽  
Dimensional Synthesis ◽  
Linkage Mechanism ◽  
Open Chain ◽  
Rehabilitation Training ◽  
Limb Rehabilitation ◽  
Lower Limb Rehabilitation

Abstract A foot-driven rehabilitation mechanism is suitable for home healthcare due to its advantages of simplicity, effectiveness, small size, and low price. However, most of the existing studies on lower limb rehabilitation movement only consider the trajectory of the ankle joint and ignore the influence of its posture angle, which makes it difficult to ensure the rotation requirements of the ankle joint and achieve a better rehabilitation effect. Aiming at the shortcomings of the current research, this paper proposes a new single degree-of-freedom (DOF) configuration that uses a noncircular gear train to constrain the three revolute joints (3R) open-chain linkage and expounds its dimensional synthesis method. Then, a parameter optimization model of the mechanism is established, and the genetic algorithm is used to optimize the mechanism parameters. According to the eight groups of key poses and position points of the ankle joint and the toe, the different configurations of the rehabilitation mechanism are synthesized and compared, and it is concluded that the newly proposed 3R open-chain noncircular gear-linkage mechanism exhibits better performance. Finally, combined with the requirements of rehabilitation training, a lower limb rehabilitation training device is designed based on this new configuration, and a prototype is developed and tested. The test results show that the device can meet the requirements of the key position points and posture angles of the ankle joint and the toe and verify the correctness of the proposed dimensional synthesis and optimization methods.

Kinematics and Workspace Analysis of 3-RPP Parallel Mechanism

2013 ◽  
Vol 456 ◽  
pp. 146-150
Author(s):  
Zhi Jiang Xie ◽  
Jun Zhang ◽  
Xiao Bo Liu
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Parallel Mechanisms ◽  
Vector Method ◽  
Workspace Analysis ◽  
Inverse Solutions ◽  
Three Degrees Of Freedom

This paper designed a kind of parallel mechanism with three degrees of freedom, the freedom and movement types of the robot are analyzed in detail, the parallel mechanisms Kinematics positive and inverse solutions are derived through using the vector method. And at last its workspace is analyzed and studied systematically.

Design and Development of a Fused Vision Force Controller for Nanofiber Grasping and Manipulation

2007 ◽  
Author(s):  
Reza Saeidpourazar ◽  
Nader Jalili
Keyword(s):  
Inverse Kinematics ◽  
Force Feedback ◽  
Atomic Scale ◽  
Design And Development ◽  
Robust Controller ◽  
Grasping And Manipulation ◽  
Performance Capability ◽  
Fabric Production ◽  
Perturbation Estimation ◽  
Vision Feedback

This paper presents the design and development of a fused vision force feedback robust controller for a nanomanipulator used in nanofiber grasping and nano-fabric production applications. The RRP (Revolute Revolute Prismatic) manipulator considered here utilizes two rotational motors with 0.1 μrad resolution and one linear Nanomotor® with 0.25 nm resolution. Weighing just about 30g and having short lever arms (<5cm), the manipulator is capable of achieving well-behaved kinematic characteristics without the backlash in addition to atomic scale precision to guarantee accurate manipulation at the nanoscale. A mathematical model of the nanomanipulator is formulated and both direct and inverse kinematics of the system as well as dynamic equations are presented. A fused force vision feedback based modified optimal robust controller with perturbation estimation for nanomanipulator positioning is then derived and analyzed extensively. Unlike typical macroscale manipulator models and controllers, the controller development is not trivial here due to nanoscale movement and forces, coupled with unmodeled dynamics, nonlinear structural dynamics and mainly lack of position and velocity feedback in this nanomanipulator. Following the development of the fused force vision robust controller, numerical simulations of the proposed controller are preformed to demonstrate the positioning performance capability in nanofiber grasping applications.

MBARS2: A New Design for a 3- Degrees of Freedom Parallel Structure for Joint Arthroplasty

2008 ◽  
Author(s):  
A. Wolf ◽  
S. Amir ◽  
A. B. Mor
Keyword(s):  
Coordinate System ◽  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Joint Arthroplasty ◽  
Robotic System ◽  
Parallel Structure ◽  
Tracking Systems ◽  
Mechanical Structure ◽  
Workspace Analysis

In this report we present the second prototype of a 3-degrees-of-freedom active, miniature bone-attached, robotic system. The report focuses on the mechanical structure, workspace analysis and inverse kinematics solution. The robot is capable of preparing the bone cavity for an implant during joint arthroplasty procedures. This system, just as its predecessor is image-free and all planning is performed intraoperatively in the robot coordinate system, eliminating the need for external tracking systems in the OR. Experiments were conducted using the first robot prototype to evaluate its accuracy and the results supported the feasibility of the concept.

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