A Unified Representation for Mapping Robot Workspace and Performance with Applications for Parallel Mechanisms

2020 ◽  
pp. 253-270
Author(s):  
Dian Li ◽  
Sheng Guo ◽  
Q. J. Ge
Keyword(s):  
Parallel Mechanisms ◽  
And Performance ◽  
Robot Workspace

Design and Prototyping of a Force-Reflecting Hand-Controller for Ultrasound Imaging

2011 ◽  
Vol 3 (2) ◽  
Author(s):  
Farshid Najafi ◽  
Nariman Sepehri
Keyword(s):  
Ultrasound Imaging ◽  
Static Friction ◽  
Parallel Mechanisms ◽  
Detailed Design ◽  
Remote Locations ◽  
Output Force ◽  
And Performance ◽  
Drive Systems ◽  
Robotic Wrist ◽  
Fixed Center

This paper presents detailed design, analysis, prototyping, and testing of a novel force-reflecting hand-controller allowing physicians to control a robotic wrist and perform ultrasound examinations on patients in remote locations. The proposed device is a four degree-of-freedom mechanism with a fixed center-of-motion and uses symmetric parallel mechanisms. All movements of the device are kinematically decoupled, i.e., the hand-controller has independent drive systems for each standard ultrasound motion. A technique has been adapted to statically balance the weight of the device over its entire workspace using a single tension spring. The prototype of the device has been constructed and evaluated for ultrasound imaging of kidney and spleen. Maximum and accuracy of the output force are analytically determined and performance of the device in terms of static balancing, static-friction break-away force, and maximum achievable impedances are experimentally evaluated.

scholarly journals On the Design of Mobile Parallel Robots for Large Workspace Applications

2011 ◽  
Author(s):  
Hai Yang ◽  
Se´bastien Krut ◽  
Franc¸ois Pierrot ◽  
Ce´dric Baradat
Keyword(s):  
Parallel Robots ◽  
Legged Robots ◽  
Parallel Mechanisms ◽  
Mobility Analysis ◽  
Design Constraints ◽  
And Performance ◽  
Forward Kinematic

In this paper, several considerations for designing industry oriented robots which combine the mobility of legged robots and advantages of parallel mechanisms are outlined. For designing such optimized robots in terms of simplicity and performance, a topology study is done based on the mobility analysis. Applying some design constraints, potential topologies of such robots are identified. One architecture is chosen for designing a tripod robot. Both inverse and forward kinematic problems of this robot are derived in order to simulate its gait motion. The analysis and simulations show that: integrating some clamping devices and some lockable passive joints, six actuators are enough to build a legged manipulator which can not only perform 6-axis machining but can also walk on a curved supporting media.

Kinematics and Performance Analysis of Two Types of 3-RPS Parallel Mechanisms

2017 ◽  
pp. 1309-1321
Author(s):  
Yongfeng Wang ◽  
Shuncheng Fan ◽  
Xiaojun Zhang ◽  
Guangda Lu ◽  
Jing Yang
Keyword(s):  
Performance Analysis ◽  
Parallel Mechanisms ◽  
And Performance

scholarly journals Kinematic analysis of a novel 3-CRU translational parallel mechanism

2015 ◽  
Vol 6 (1) ◽  
pp. 57-64 ◽  
Author(s):  
B. Li ◽  
Y. M. Li ◽  
X. H. Zhao ◽  
W. M. Ge
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Jacobian Matrix ◽  
Screw Theory ◽  
Structural Characteristics ◽  
Parallel Mechanisms ◽  
Reachable Workspace ◽  
Potential Applications ◽  
Moving Platform ◽  
And Performance

Abstract. In this paper, a modified 3-DOF (degrees of freedom) translational parallel mechanism (TPM) three-CRU (C, R, and U represent the cylindrical, revolute, and universal joints, respectively) structure is proposed. The architecture of the TPM is comprised of a moving platform attached to a base through three CRU jointed serial linkages. The prismatic motions of the cylindrical joints are considered to be actively actuated. Kinematics and performance of the TPM are studied systematically. Firstly, the structural characteristics of the mechanism are described, and then some comparisons are made with the existing 3-CRU parallel mechanisms. Although these two 3-CRU parallel mechanisms are both composed of the same CRU limbs, the types of freedoms are completely different due to the different arrangements of limbs. The DOFs of this TPM are analyzed by means of screw theory. Secondly, both the inverse and forward displacements are derived in closed form, and then these two problems are calculated directly in explicit form. Thereafter, the Jacobian matrix of the mechanism is derived, the performances of the mechanism are evaluated based on the conditioning index, and the performance of a 3-CRU TPM changing with the actuator layout angle is investigated. Thirdly, the workspace of the mechanism is obtained based on the forward position analysis, and the reachable workspace volume is derived when the actuator layout angle is changed. Finally, some conclusions are given and the potential applications of the mechanism are pointed out.

scholarly journals Parallel Architectures for Humanoid Robots

Robotics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 75
Author(s):  
Marco Ceccarelli ◽  
Matteo Russo ◽  
Cuauhtemoc Morales-Cruz
Keyword(s):  
International Symposium ◽  
Mechanical Performance ◽  
Humanoid Robots ◽  
Parallel Architectures ◽  
Human Anatomy ◽  
Parallel Mechanisms ◽  
Design Issues ◽  
Parallel Kinematic ◽  
And Performance ◽  
Kinematic Mechanisms

The structure of humanoid robots can be inspired to human anatomy and operation with open challenges in mechanical performance that can be achieved by using parallel kinematic mechanisms. Parallel mechanisms can be identified in human anatomy with operations that can be used for designing parallel mechanisms in the structure of humanoid robots. Design issues are outlined as requirements and performance for parallel mechanisms in humanoid structures. The example of LARMbot humanoid design is presented as from direct authors’ experience to show an example of the feasibility and efficiency of using parallel mechanisms in humanoid structures. This work is an extension of a paper presented at ISRM 2019 conference (International Symposium on Robotics and Mechatronics).

Design, implementation, and performance evaluation of a 4-DOF parallel robot

Robotica ◽  
2009 ◽  
Vol 28 (1) ◽  
pp. 107-118 ◽  
Author(s):  
Hee-Byoung Choi ◽  
Atsushi Konno ◽  
Masaru Uchiyama
Keyword(s):  
Performance Evaluation ◽  
Parallel Mechanism ◽  
High Speed ◽  
Parallel Robot ◽  
Necessary Condition ◽  
Parallel Mechanisms ◽  
System Configuration ◽  
Tracking Accuracy ◽  
New Type ◽  
And Performance

SUMMARYThis paper deals with the design, implementation, and performance evaluation of a new type of 4-DOF parallel mechanism providing three translations and one rotation for high-speed handling and machining. This parallel mechanism is named H4. A necessary condition and system configuration of the H4 are also described. Hardware and kinematics of the H4 is addressed and the manipulability ellipsoid which is one of the widely used methods to examine the design of parallel mechanisms is addressed. The performance evaluation is carried out to demonstrate the H4 robot. The simulation and experimental results show that three different controllers, the PD, PD + velocity feed-forward, and dynamic compensation controller, dramatically improve the trajectory tracking accuracy.

Flexure Parallel Mechanism: Configuration and Performance Improvement of a Compact Acceleration Sensor

2012 ◽  
Vol 4 (3) ◽  
Author(s):  
Zhen Gao ◽  
Dan Zhang
Keyword(s):  
Parallel Mechanism ◽  
Structure Evolution ◽  
Cantilever Beams ◽  
Parallel Mechanisms ◽  
Acceleration Sensor ◽  
Element Analysis ◽  
Revolute Joints ◽  
Kinematics Modeling ◽  
And Performance ◽  
Monolithic Structure

This research presents a tridimensional acceleration sensor based on flexure parallel mechanism (FPM). Three perpendicular compliant limbs with compact monolithic structure are developed to serve as the elastic component for acquiring the inertial signals in each direction. With integrated flexure hinges, each chain containing multiple revolute joints and cantilever beams are designed to carry compressive and tensile loads. First, the structure evolution and kinematics modeling are introduced, followed by the multispring modeling of the directional compliance for the flexure limb. Then, the comprehensive finite-element analysis (FEA) including the strain of the sensitive limbs, modal analysis for total deformation under different frequency is conducted. The compliances calculated by FEA and multispring model are compared. Finally, the dimensional optimization is implemented based on multipopulation genetic algorithm to obtain the optimal flexure parameters. The proposed methods and algorithms are also useful for the analysis and development of other flexure parallel mechanisms.

Transmission Scanning Electron Microscopy and Energy Analysis with the Siemens ELMISKOP 101

1972 ◽  
Vol 30 ◽  
pp. 450-451
Author(s):  
H. M. Thieringer
Keyword(s):  
Objective Lens ◽  
Transmission Microscopy ◽  
Image Recording ◽  
Mode Of Operation ◽  
Scanning Transmission ◽  
Electron Microscopes ◽  
And Performance ◽  
Convergent Beam ◽  
Ray Path ◽  
Beam Diffraction

It has repeatedly been show that with conventional electron microscopes very fine electron probes can be produced, therefore allowing various micro-techniques such as micro recording, X-ray microanalysis and convergent beam diffraction. In this paper the function and performance of an SIEMENS ELMISKOP 101 used as a scanning transmission microscope (STEM) is described. This mode of operation has some advantages over the conventional transmission microscopy (CTEM) especially for the observation of thick specimen, in spite of somewhat longer image recording times.Fig.1 shows schematically the ray path and the additional electronics of an ELMISKOP 101 working as a STEM. With a point-cathode, and using condensor I and the objective lens as a demagnifying system, an electron probe with a half-width ob about 25 Å and a typical current of 5.10-11 amp at 100 kV can be obtained in the back focal plane of the objective lens.

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