scholarly journals Kinematic analysis and evaluation of a hybrid mechanism for computer assisted bone reduction surgery

2019 ◽  
Vol 10 (2) ◽  
pp. 589-604 ◽  
Author(s):  
Sinh Nguyen Phu ◽  
Terence Essomba ◽  
Irwansyah Idram ◽  
Jiing-Yi Lai
Keyword(s):  
Parallel Mechanism ◽  
Simulation Software ◽  
Computer Assisted ◽  
Advanced Technique ◽  
Analysis And Evaluation ◽  
Parasitic Motion ◽  
Velocity Models ◽  
Hybrid Mechanism ◽  
Bone Fragments ◽  
Classical Mechanism

Abstract. In severe fracture cases, a bone can be separated into two fragments and it is mandatory to reposition the bone fragments together. This type of surgery is called “bone reduction surgery”. Originally, the operation consisted in manipulating the bones fragments by hand in open surgery. The most advanced technique relies on robotic manipulators providing higher precision and stability. A new mechanical architecture is proposed based on a 3-RPS tripod parallel mechanism combined with a Double Triangular Planar parallel mechanism. Its kinematic and velocity models are calculated and the parasitic motion generated by the tripod mechanism is considered in the final result. The workspace it can generate is compared to the Stewart manipulator, which is a classical mechanism for the targeted application. The use of a robotic manipulator is due to be part of an entire surgical procedure involving a pre-operative simulation software dedicated to pre-planning reduction surgery, namely PhysiGuide. It is used to measure the kinematic associated with bone fragments manipulation and transfer it to the robot during the intra-operative phase. Simulations are then performed based on a real patient's fracture images showing the suitability of the present mechanism with bone reduction surgery.

Kinematic design of a hybrid planar-tripod mechanism for bone reduction surgery

2020 ◽  
Vol 21 (4) ◽  
pp. 403
Author(s):  
Terence Essomba ◽  
Sinh Nguyen Phu
Keyword(s):  
Motion Compensation ◽  
Bone Fractures ◽  
Advanced Technique ◽  
Planar Mechanism ◽  
Kinematic Design ◽  
Parasitic Motion ◽  
Velocity Models ◽  
Hybrid Mechanism ◽  
Bone Fragments ◽  
Kinematic Simulations

In the most severe cases of longitudinal bone fractures such as femur, tibias, humerus etc., the bone can be completely separated into two fragments. In order to guarantee the re-ossification of the bone, it is required to reposition the bone fragments together. This process requires a delicate surgery called “bone reduction surgery”. The most advanced technique relies on the use of a robotic manipulator to reposition the bone fragments with higher precision and stability than manual surgeries. The present work introduces the kinematic design of a new hybrid mechanical architecture to perform this task. It is composed of a 3-PRP planar mechanism attached with a 3-RPS tripod mechanism. The kinematic analysis of this mechanism is provided while taking account the tripod parasitic motion. Kinematic simulations using Matlab and Adams are performed to validate the kinematic and velocity models and the parasitic motion compensation provided by the planar mechanism. The workspace of this hybrid mechanism is then compared to the standard hexapod mechanism that is widely used in bone reduction surgery. It reveals that the proposed mechanism can generate a larger workspace with the same linkage dimensions.

Kinematic analysis and design of a novel 6-degree of freedom parallel robot

2014 ◽  
Vol 229 (2) ◽  
pp. 291-303 ◽  
Author(s):  
DU Hui ◽  
GAO Feng ◽  
PAN Yang
Keyword(s):  
Set Theory ◽  
Kinematic Analysis ◽  
Parallel Mechanism ◽  
Design Methodology ◽  
Parallel Robot ◽  
End Effector ◽  
Analysis And Design ◽  
Velocity Models ◽  
Reachable Workspace ◽  
Rotational Motions

A novel 3-UP3R parallel mechanism with six degree of freedoms is proposed in this paper. One most important advantage of this mechanism is that the three translational and three rotational motions are partially decoupled: the end-effector position is only determined by three inputs, while the rotational angles are relative to all six inputs. The design methodology via GF set theory is brought out, using which the limb type can be determined. The mobility of the end-effector is analyzed. After that, the kinematic and velocity models are formulated. Then, workspace is studied, and since the robot is partially decoupled, the reachable workspace is also the dexterous workspace. In the end, both local and global performances are discussed using conditioning indexes. The experiment of real prototype shows that this mechanism works well and may be applied in many fields.

Type Synthesis of a 1T Symmetric Coupling Mechanism with the Method of Separation and Merger

2014 ◽  
Vol 635-637 ◽  
pp. 1290-1293
Author(s):  
Shou Li Zhang ◽  
Jing Fang Liu ◽  
Yue Qing Yu
Keyword(s):  
Linear Combination ◽  
Parallel Mechanism ◽  
Creative Design ◽  
Coupling Mechanism ◽  
Type Synthesis ◽  
Structural Synthesis ◽  
Hybrid Mechanism ◽  
Coupled Structures ◽  
Coupling Mechanisms

The structural synthesis is the primary and the most important issue in the process of mechanism creative design. In the paper, Firstly, select a 1T symmetric parallel mechanism, and the constraint and mobility of the branches can be analyzed. With the method of linear combination of the screws, the new branches are constructed. Then, using the measure of separation and merger, parts of the limbs of the parallel mechanism can be replaced by equivalent coupled structures, so corresponding symmetric coupling mechanisms with equal mobility are synthesized. Finally, solving the constraint screws of the branch of the coupling mechanism, in order to prove the hybrid mechanism is full-cycle or not.

scholarly journals A practical method for planning large number of horizontal wells with a reservoir model for a field development plan

2021 ◽  
Vol 10 ◽  
pp. 17-32
Author(s):  
Guido Fava ◽  
Việt Anh Đinh
Keyword(s):  
Horizontal Well ◽  
Horizontal Wells ◽  
Simulation Software ◽  
Production Performance ◽  
Development Plan ◽  
Regular Pattern ◽  
Production Forecast ◽  
Advanced Technique ◽  
Large Reservoir ◽  
Field Development

The most advanced technique to evaluate different solutions proposed for a field development plan consists of building a numerical model to simulate the production performance of each alternative. Fields covering hundreds of square kilometres frequently require a large number of wells. There are studies and software concerning optimal planning of vertical wells for the development of a field. However, only few studies cover planning of a large number of horizontal wells seeking full population on a regular pattern. One of the criteria for horizontal well planning is selecting the well positions that have the best reservoir properties and certain standoffs from oil/water contact. The wells are then ranked according to their performances. Other criteria include the geometry and spacing of the wells. Placing hundreds of well individually according to these criteria is highly time consuming and can become impossible under time restraints. A method for planning a large number of horizontal wells in a regular pattern in a simulation model significantly reduces the time required for a reservoir production forecast using simulation software. The proposed method is implemented by a computer script and takes into account not only the aforementioned criteria, but also new well requirements concerning existing wells, development area boundaries, and reservoir geological structure features. Some of the conclusions drawn from a study on this method are (1) the new method saves a significant amount of working hours and avoids human errors, especially when many development scenarios need to be considered; (2) a large reservoir with hundreds of wells may have infinite possible solutions, and this approach has the aim of giving the most significant one; and (3) a horizontal well planning module would be a useful tool for commercial simulation software to ease engineers' tasks.

A New Extensible Continuum Manipulator Using Flexible Parallel Mechanism and Rigid Motion Transmission

2021 ◽  
pp. 1-23
Author(s):  
Yujiong Liu ◽  
Pinhas Ben-Tzvi
Keyword(s):  
Parallel Mechanism ◽  
Kinematic Model ◽  
Rigid Motion ◽  
Artificial Muscle ◽  
Dexterous Manipulation ◽  
Base Extension ◽  
Hybrid Mechanism ◽  
Continuum Robot ◽  
Kinematic Analyses ◽  
Continuum Manipulator

Abstract An extensible continuum manipulator (ECM) has specific advantages over its non-extensible counterparts. For instance, in certain applications, such as minimally invasive surgery or pipe inspection, the base motion might be limited or disallowed. The additional extensibility provides the robot with more dexterous manipulation and a larger workspace. Existing continuum robot designs achieve extensibility mainly through artificial muscle/pneumatic, extensible backbone, concentric tube, and base extension, etc. This paper proposes a new way to achieve this additional motion degree of freedom by taking advantage of the rigid coupling hybrid mechanism concept and a flexible parallel mechanism. More specifically, a rack and pinion set is used to transmit the motion of the i-th subsegment to drive the (i+1)-th subsegment. A six-chain flexible parallel mechanism is used to generate the desired spatial bending and one extension mobility for each subsegment. This way, the new manipulator can achieve tail-like spatial bending and worm-like extension at the same time. Simplified kinematic analyses are conducted to estimate the workspace and the motion non-uniformity. A proof-of-concept prototype was integrated to verify the mechanism’s mobility and to evaluate the kinematic model accuracy. The results show that the proposed mechanism achieved the desired mobilities with a maximum extension ratio of 32.2% and a maximum bending angle of 80 degrees.

scholarly journals Design and Analysis of a Flexible, Elastic, and Rope-Driven Parallel Mechanism for Wrist Rehabilitation

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Zaixiang Pang ◽  
Tongyu Wang ◽  
Junzhi Yu ◽  
Shuai Liu ◽  
Xiyu Zhang ◽  
...  
Keyword(s):  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Inverse Kinematic ◽  
Parallel Structure ◽  
Flexible Joints ◽  
Rehabilitation Robots ◽  
Hybrid Mechanism ◽  
Compression Spring ◽  
Moving Platform

This paper proposes a bionic flexible wrist parallel mechanism to simulate human wrist joints, which is characterized by a rope-driven, compression spring-supported hybrid mechanism. Specifically, to realize the movement of the wrist mechanism, a parallel structure is adopted to support the mobile platform and is controlled by a cable, which plays the role of wrist muscles. Because the compression spring is elastic, it is difficult to directly solve inverse kinematics. To address this problem, the external force acting on the moving platform is firstly equivalent to the vector force and torque at the center of the moving platform. Then, based on inverse kinematic and static analyses, the inverse motion of the robot model can be solved according to the force and torque balance conditions and the lateral spring bending equation of the compression spring. In order to verify the proposed method, kinematics, statics, and parallel mechanism workspace are further analyzed by the software MATLAB. The obtained results demonstrate the effectiveness and feasibility of the designed parallel mechanism. This work offers new insights into the parallel mechanism with flexible joints in replicating the movements of the human wrist, thus promoting the development of rehabilitation robots and rope-driven technology to some extent.

Reactionless Two-Degree-of-Freedom Planar Parallel Mechanism With Variable Payload

2009 ◽  
Author(s):  
Alexandre Lecours ◽  
Cle´ment Gosselin
Keyword(s):  
Dynamic Simulation ◽  
Parallel Mechanism ◽  
Reaction Force ◽  
Simulation Software ◽  
Degree Of Freedom ◽  
Dynamic Balancing ◽  
End Effector ◽  
Planar Mechanism ◽  
Two Degree Of Freedom ◽  
Arbitrary Trajectory

A reactionless mechanism is one which does not exert any reaction force or moment on its base at all times, for any arbitrary trajectory of the mechanism. This paper addresses the static and dynamic balancing of a two-degree-of-freedom parallel planar mechanism (five-bar mechanism). A simple and effective adaptive balancing method is presented that allows the mechanism to maintain the reactionless condition for a range of payloads. Important proofs concerning the balancing of five-bar mechanisms are also presented. The design of a real mechanism where parallelogram linkages are used to produce pure translations at the end-effector is also presented. Finally, using dynamic simulation software, it is shown that the mechanism is reactionless for arbitrarily chosen trajectories and for a variety of payloads.

Key Technologies in Design and Realization of Simulation Software for the Satellite Experimentations’ Inversion

2012 ◽  
Vol 241-244 ◽  
pp. 2872-2877
Author(s):  
Lei Shi ◽  
Zhi Li ◽  
Can Xu ◽  
Yong Zhe Shao
Keyword(s):  
Observational Data ◽  
Software Design ◽  
Design Method ◽  
Simulation Software ◽  
Inverse Theory ◽  
Analysis And Evaluation ◽  
Overall Design ◽  
Key Technologies ◽  
Developing Platform ◽  
Energy Conservation Principle

To fulfill the requirements of processing, analysis and inversing the observational data of experimentations, simulation software for the inversion of satellite experimentations is designed and developed independently on the developing platform of Qt, based on satellite observational data inverse theory. It provides a simulation and calculation platform for analysis and evaluation of space tests. By using dynamics principle and energy conservation principle, the software resolves inverse problems in satellite orbital dynamics. This article mainly presents the function and design method of the software, explains the design goals, shows the overall design framework, and emphasizes key technologies and countermeasures in process of the software design and realization. The software could be used to investigate the inversion of observational data and evaluate technologic indexes in satellite tests.

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