Design and kinematic modeling of an origami-inspired cable-driven flexible arm

2021 ◽  
pp. 095440622110358
Author(s):  
Jiali Liu ◽  
Yong Xu ◽  
Haorang Shi ◽  
Jie Yang
Keyword(s):  
Three Dimensional ◽  
Variable Stiffness ◽  
Joint Space ◽  
Environment Interaction ◽  
Kinematic Modeling ◽  
Flexible Arm ◽  
Structural Environment ◽  
Kinematic Models ◽  
Variable Configuration ◽  
Compliant Actuator

The cable-driven flexible arm based on the principle of origami is a new type of non-articulated compliant actuator with high integration, high environmental adaptability, large workspace/large deployment ratio. The forward/reverse kinematic models of joint space, operation space and driving space along with trajectory error model of the cable-driven flexible arm were proposed in this paper. The prototype of the flexible arm was developed capable of realizing bending, torsion and expansion/contraction. The simulation and experiment results of the cable-driven foldable flexible arm verified feasibility of the kinematic models and driving method proposed in this paper. Above research achievements lay necessary foundation for the next step to realize the key service functions of grasping/manipulation, three-dimensional precise movement, non-structural environment interaction/adaptation of the flexible arm with variable stiffness, variable configuration and variable size.

scholarly journals Human and bird detection and classification based on Doppler radar spectrograms and vision images using convolutional neural networks

2021 ◽  
Vol 18 (3) ◽  
pp. 172988142110105
Author(s):  
Jnana Sai Abhishek Varma Gokaraju ◽  
Weon Keun Song ◽  
Min-Ho Ka ◽  
Somyot Kaitwanidvilai
Keyword(s):  
Neural Networks ◽  
Object Recognition ◽  
Convolutional Neural Networks ◽  
Doppler Radar ◽  
Autonomous Vehicle ◽  
Sampling Point ◽  
Body Segment ◽  
Kinematic Modeling ◽  
Deep Convolutional Neural Networks ◽  
Kinematic Models

The study investigated object detection and classification based on both Doppler radar spectrograms and vision images using two deep convolutional neural networks. The kinematic models for a walking human and a bird flapping its wings were incorporated into MATLAB simulations to create data sets. The dynamic simulator identified the final position of each ellipsoidal body segment taking its rotational motion into consideration in addition to its bulk motion at each sampling point to describe its specific motion naturally. The total motion induced a micro-Doppler effect and created a micro-Doppler signature that varied in response to changes in the input parameters, such as varying body segment size, velocity, and radar location. Micro-Doppler signature identification of the radar signals returned from the target objects that were animated by the simulator required kinematic modeling based on a short-time Fourier transform analysis of the signals. Both You Only Look Once V3 and Inception V3 were used for the detection and classification of the objects with different red, green, blue colors on black or white backgrounds. The results suggested that clear micro-Doppler signature image-based object recognition could be achieved in low-visibility conditions. This feasibility study demonstrated the application possibility of Doppler radar to autonomous vehicle driving as a backup sensor for cameras in darkness. In this study, the first successful attempt of animated kinematic models and their synchronized radar spectrograms to object recognition was made.

Radula-centric and odontophore-centric kinematic models of swallowing inAplysia californica

2002 ◽  
Vol 205 (14) ◽  
pp. 2029-2051 ◽  
Author(s):  
Richard F. Drushel ◽  
Greg P. Sutton ◽  
David M. Neustadter ◽  
Elizabeth V. Mangan ◽  
Benjamin W. Adams ◽  
...  
Keyword(s):  
Kinematic Model ◽  
Three Dimensional ◽  
Rigid Bodies ◽  
High Temporal Resolution ◽  
Buccal Mass ◽  
Kinematic Models ◽  
Dimensional Shape ◽  
Position Parameter ◽  
Three Dimensional Shape

SUMMARYTwo kinematic models of the radula/odontophore of the marine mollusc Aplysia californica were created to characterize the movement of structures inside the buccal mass during the feeding cycle in vivo. Both models produce a continuous range of three-dimensional shape changes in the radula/odontophore, but they are fundamentally different in construction. The radulacentric model treats the radular halves as rigid bodies that can pitch, yaw and roll relative to a fixed radular stalk, thus creating a three-dimensional shape. The odontophore-centric model creates a globally convex solid representation of the radula/odontophore directly, which then constrains the positions and shapes of internal structures. Both radula/odontophore models are placed into a pre-existing kinematic model of the I1/I3 and I2 muscles to generate three-dimensional representations of the entire buccal mass. High-temporal-resolution, mid-sagittal magnetic resonance(MR) images of swallowing adults in vivo are used to provide non-invasive, artifact-free shape and position parameter inputs for the models. These images allow structures inside the buccal mass to be visualized directly, including the radula, radular stalk and lumen of the I1/I3 cavity. Both radula-centric and odontophore-centric models were able to reproduce two-dimensional, mid-sagittal radula/odontophore and buccal mass kinematics,but the odontophore-centric model's predictions of I1/I3, I2 and I7 muscle dimensions more accurately matched data from MR-imaged adults and transilluminated juveniles.

Development and Validation of a Three-Dimensional Printed Training Model to Teach Ultrasound-Guided Injections of the Cervical Articular Process Joints in Horses

2021 ◽  
pp. e20200137
Author(s):  
Alexandra Beaulieu ◽  
Stephanie Nykamp ◽  
John Phillips ◽  
Luis G. Arroyo ◽  
Judith Koenig ◽  
...  
Keyword(s):  
Construct Validity ◽  
Content Validity ◽  
Three Dimensional ◽  
Joint Space ◽  
Needle Placement ◽  
Ultrasound Guided ◽  
Training Tool ◽  
Articular Process ◽  
The Face ◽  
3D Printed

Intra-articular injections are routinely performed to alleviate pain and inflammation associated with osteoarthritis in horses. Intra-articular injections require accurate needle placement to optimize clinical outcomes and minimize complications. This study’s objectives were to develop and validate a three-dimensional (3D) printed model of an equine cervical articular process joint to teach ultrasound-guided injections. Five identical models of an equine cervical articular process joint were 3D printed and embedded in 10% ballistic gelatin. Experts’ and novices’ ability to successfully insert a needle into the joint space of the model using ultrasound guidance was assessed and graded using an objective structured clinical examination (OSCE). Scores from experts and novices were compared to evaluate the construct validity of the model. Participants also answered a survey assessing the face and content validity of the model. Experts required less time (22.51 seconds) for correct needle placement into the model joint space than novices (35.96 seconds); however, this difference was not significant ( p = .53). Experts’ median total OSCE score (14) was significantly higher ( p = .03) than novices’ (12), supporting the model’s construct validity. Participants agreed on the face and content validity of the model by grading all survey questions greater than 7 on a 10-point Likert-type scale. In summary, we successfully developed a 3D printed model of an equine cervical articular process joint, partially demonstrated the construct validity of the model, and proved the face and content validity of this new training tool.

A Fully Multi-Material Three-Dimensional Printed Soft Gripper with Variable Stiffness for Robust Grasping

Soft Robotics ◽  
2019 ◽  
Vol 6 (4) ◽  
pp. 507-519 ◽  
Author(s):  
Mingzhu Zhu ◽  
Yoshiki Mori ◽  
Tatsuhiro Wakayama ◽  
Akira Wada ◽  
Sadao Kawamura
Keyword(s):  
Three Dimensional ◽  
Variable Stiffness

scholarly journals Conceptual Design and Computational Modeling Analysis of a Single-Leg System of a Quadruped Bionic Horse Robot Driven by a Cam-Linkage Mechanism

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Liangwen Wang ◽  
Weiwei Zhang ◽  
Caidong Wang ◽  
Fannian Meng ◽  
Wenliao Du ◽  
...  
Keyword(s):  
Motion Analysis ◽  
Kinematic Analysis ◽  
Degrees Of Freedom ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Kinematic Modeling ◽  
Linkage Mechanism ◽  
Vector Method ◽  
Pressure Angle ◽  
End Point

In this study, the configuration of a bionic horse robot for equine-assisted therapy is presented. A single-leg system with two degrees of freedom (DOFs) is driven by a cam-linkage mechanism, and it can adjust the span and height of the leg end-point trajectory. After a brief introduction on the quadruped bionic horse robot, the structure and working principle of a single-leg system are discussed in detail. Kinematic analysis of a single-leg system is conducted, and the relationships between the structural parameters and leg trajectory are obtained. On this basis, the pressure angle characteristics of the cam-linkage mechanism are studied, and the leg end-point trajectories of the robot are obtained for several inclination angles controlled by the rotation of the motor for the stride length adjusting. The closed-loop vector method is used for the kinematic analysis, and the motion analysis system is developed in MATLAB software. The motion analysis results are verified by a three-dimensional simulation model developed in Solidworks software. The presented research on the configuration, kinematic modeling, and pressure angle characteristics of the bionic horse robot lays the foundation for subsequent research on the practical application of the proposed bionic horse robot.

Study on Rational Use of the Sucker Rod String Vibration Energy Mechanism

2013 ◽  
Vol 694-697 ◽  
pp. 325-328
Author(s):  
Su Ling Wang ◽  
Nan Yang Bai ◽  
Ming Xi Feng ◽  
Huai Yu Zhang
Keyword(s):  
Three Dimensional ◽  
Variable Stiffness ◽  
Liquid Column ◽  
Vibration Energy ◽  
Rational Use ◽  
String Vibration ◽  
Unit Energy ◽  
Sucker Rod ◽  
Polished Rod ◽  
The Impact

Rational and efficient use of the sucker rod vibration energy is one of the effective ways of pumping unit energy saving. The vibration mechanics as the basis for establishing three-dimensional coupled vibration mathematical model of sucker rod-tubing-liquid column, and using difference solution to reproduce vibration process within one stroke of the sucker rod string, on this basis, analyzing the variable stiffness sucker rod string to the impact of the polished rod load and the pump stroke, and gaining reasonable parameters of the sucker rod string vibration energy, and combining with the working conditions of the sucker rod string to establish the match conditions of the sucker rod string liquid column incentive and polished rod incentive, and proposing the condition of pump to generate over-stroke to provide the theoretical basis for rational use of the sucker rod string vibration energy.

Thrust tectonics: a personal view

1985 ◽  
Vol 122 (3) ◽  
pp. 223-232 ◽  
Author(s):  
Robert W. H. Butler
Keyword(s):  
Cross Sections ◽  
Analytical Methods ◽  
Three Dimensional ◽  
Personal View ◽  
Driving Mechanisms ◽  
Thrust Belts ◽  
Structural Environment ◽  
Thrust Tectonics ◽  
Orogenic Belts ◽  
Future Work

AbstractThe structure of fold and thrust belts has been studied for just over one hundred years and has been the subject of a recent international conference at Toulouse, in May 1984. This article reviews some of the recent advances in thrust tectonics from a personal viewpoint, in the light of the Toulouse meeting. Key tools in correctly interpreting thrust systems are the use of balanced (restorable) cross-sections and the resolution of three dimensional fault systems. These analytical methods are now being widely developed and applied to numerous orogenic belts with many surprising results. While our understanding of foreland thrust belts is now probably better than any other structural environment, there is still great uncertainty as to the emplacement-driving mechanisms of these belts. Future work will try to solve these and other outstanding problems and apply the new analytical methods to the interior parts of thrust belts in efforts to restore entire orogens.

Kinematic constraining of the multi-fault rupture dynamics of the Norcia, Mw 6.5, 30 October 2016, Central Italy earthquake

2020 ◽  
Author(s):  
Elisa Tinti ◽  
Emanuele Casarotti ◽  
Alice-Agnes Gabriel ◽  
Taufiqurrahman Taufiqurrahman ◽  
Thomas Ulrich ◽  
...  
Keyword(s):  
Central Italy ◽  
Source Inversion ◽  
Fault Rupture ◽  
Kinematic Modeling ◽  
Dynamic Rupture ◽  
Multiple Faults ◽  
Initial Strength ◽  
Central Italy Earthquake ◽  
Kinematic Models ◽  
Geological Constraints

<p>The 2016 Central Italy sequence showed a remarkable complexity involving multiple faults. Highly heterogeneous slip distributions were inferred from kinematic finite source inversions. The coverage and quality of the geodetic and seismic data allow resolving high-resolution details of rupture kinematics of the largest event of the sequence, the Mw 6.5 30 October 2016 Norcia earthquake. Composite fault rupture models suggest that two fault planes may have slipped simultaneously. Nevertheless, kinematic modeling cannot assess the mechanic viability of such multiple fault plane models.</p><p>Using SeisSol, a software package for simulating wave propagation and dynamic rupture based on the arbitrary high-order accurate derivative discontinuous Galerkin method, we therefore try to generate spontaneous dynamic ruptures models compatible with the two fault planes constrained by kinematic inversions. To this end, we adopt a simple slip-weakening friction law with spatially variable dynamic friction and initial strength parameters along multiple faults, compatible with the slip distributions found in the literature. Although we do not to aim to explore the full parameter space, our approach allows testing the feasibility of kinematic models in conjunction with successfully generating spontaneous dynamic rupture scenarios matching seismic and geodetic observations with geological constraints. Such linking enhances and validates the physical implications of kinematic earthquake source inversion.</p>

Application of CT Image Based on Three-Dimensional Image Segmentation Algorithm in Diagnosis of Osteoarthritis

2021 ◽  
Vol 11 (1) ◽  
pp. 230-234
Author(s):  
Songlin Liu ◽  
Dasheng Gai ◽  
Qun Lu ◽  
Hanyuan Zhang ◽  
Xu Kuang ◽  
...  
Keyword(s):  
Facet Joint ◽  
Articular Surface ◽  
Three Dimensional ◽  
Spiral Ct ◽  
Joint Space ◽  
Joint Disease ◽  
Facet Joints ◽  
Surface Destruction ◽  
Lumbar Facet ◽  
Image Segmentation Algorithm

Objective: To investigate the application of multi-slice spiral CT in degenerative changes of lumbar facet joints using the LOG algorithm. Methods: The CT findings of 100 cases of degenerative vertebral facet joint disease were reviewed and analyzed in this paper. Results: The main CT manifestations of facet disease are osteophyte formation, articular hyperplasia and hypertrophy, osteosclerosis, narrowing of joint space, articular surface destruction, joint capsule calcification, joint gas accumulation, joint subluxation, and lateral recesses and vertebrae. Signs such as narrow mesopores. Conclusion: The multi-slice spiral CT (MSCT) and multi-planar reconstruction (MPR) techniques are analyzed by the LOG operator algorithm. It is found that the two techniques can fully display the anatomical structure and pathological changes of the vertebral facet joints, and are useful for the diagnosis of facet joint disease. Provide enough imaging evidence.

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