Design, Modeling, and Integration of a Flexible Universal Spatial Robotic Tail

This paper presents the novel design of a bioinspired robot capable of generating spatial loading relative to its base. By looking to nature at how animals utilize their tails, a bioinspired structure is developed that utilizes a redundant serial chain of rigid links to mimic the continuous deformation of a biological tail. Individual links are connected by universal joints to enable a spatial robot workspace capable of generating spatial loading comprised of pitch, yaw, and roll direction contributions. Two sets of three cables are used to create two actuated segments along the robot. A dynamic model of the robot is derived using prescribed cable displacement trajectories as inputs to determine the resulting joint angle trajectories and cable tensions. Sensors are integrated on-board the robot to calculate joint angles and joint velocities in real-time for use in feedback control. The loading capabilities of the robot are analyzed, and an experimental prototype is integrated and demonstrated.

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Inverse Solution and Optimal Concept Rethink from Human Operation to Industrial Redundant Manipulator

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.541-542.1140 ◽

2014 ◽

Vol 541-542 ◽

pp. 1140-1145 ◽

Cited By ~ 2

Author(s):

Mei Ling Wang ◽

Min Zhou Luo ◽

Xin Lin

Keyword(s):

Real Time ◽

Computational Efficiency ◽

Inverse Kinematics ◽

Joint Angle ◽

Inverse Solution ◽

Joint Movement ◽

Redundant Manipulator ◽

Joint Angles ◽

Human Arm ◽

Dual Arm

More and more dual arm robots with redundant manipulator are introduced in industrial fields. Here we focus on this special structure with 7-DOF redundant manipulator, an exhibit analytical and optimal concept was proposed. The formula derivations of inverse kinematics showed that when the redundant joint angle has been obtained, the remaining six joint angles can be derived analytically, and there are eight sets of inverse solution for one giving redundant joint angle. Reversed thinking the joint movement habits, patterns, and frequency of human arm operations, an optimal concept was presented to gain a real time computational efficiency of a direct inverse solution while also achieving the purpose of application.

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Whole-Body Joint Angle Estimation for Real-Time Humanoid Robot Imitation Based on Gaussian Process Dynamical Model and Particle Filter

Applied Sciences ◽

10.3390/app10010005 ◽

2019 ◽

Vol 10 (1) ◽

pp. 5

Author(s):

Jian Mi ◽

Yasutake Takahashi

Keyword(s):

Particle Filter ◽

Real Time ◽

Humanoid Robot ◽

Joint Angle ◽

Computational Cost ◽

High Dimensional ◽

Motion Model ◽

Joint Angles ◽

Compact State ◽

Low Computational Cost

Real-time imitation enables a humanoid robot to mirror the behavior of humans, being important for applications of human–robot interaction. For imitation, the corresponding joint angles of the humanoid robot should be estimated. Generally, a humanoid robot comprises dozens of joints that construct a high-dimensional exploration space for estimating the joint angles. Although a particle filter can estimate the robot state and provides a solution for estimating joint angles, the computational cost becomes prohibitive given the high dimension of the exploration space. Furthermore, a particle filter can only estimate the joint angles accurately using a motion model. To realize accurate joint angle estimation at low computational cost, Gaussian process dynamical models (GPDMs) can be adopted. Specifically, a compact state space can be constructed through the GPDM learning of high-dimensional time-series motion data to obtain a suitable motion model. We propose a GPDM-based particle filter using a compact state space from the learned motion models to realize efficient estimation of joint angles for robot imitation. Simulations and real experiments demonstrate that the proposed method efficiently estimates humanoid robot joint angles at low computational cost, enabling real-time imitation.

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Analysis of a misalignment-insensitive spur gear transmission using a Rzeppa joint

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406220950354 ◽

2020 ◽

pp. 095440622095035

Author(s):

Zhaksylyk Galym ◽

Christos Spitas

Keyword(s):

Real Time ◽

Contact Stress ◽

Spur Gear ◽

Joint Interface ◽

The Novel ◽

Mesh Stiffness ◽

Internal Interface ◽

Trade Off ◽

Constant Stiffness ◽

Novel Design

The design of a novel gear system based on a Rzeppa joint internal interface is presented and analysed. The joint allows the transmission of torque loads while allowing real-time re-alignment of the gear to eliminate non-torque loads arising from misalignment. This gear, when part of a misaligned pair, is shown by means of quasi-static FE simulations to remain essentially under the same stress conditions, even when under considerable misalignment, and to outperform crowned gears. The trade-off is increased contact stress at the ball elements of the joint interface. In addition, the mesh stiffness for the conventional and the novel design are estimated, showing that the proposed design produces a lower but nearly constant stiffness throughout the mesh cycle.

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Dynamic Model For Solar Hydrogen Via Alkaline Water Electrolyzer: A Real-Time Techno-economic Perspective With And Without Energy Storage System

2020 20th International Conference on Control, Automation and Systems (ICCAS) ◽

10.23919/iccas50221.2020.9268396 ◽

2020 ◽

Author(s):

Haider Niaz ◽

Jay Liu

Keyword(s):

Energy Storage ◽

Real Time ◽

Dynamic Model ◽

Storage System ◽

Energy Storage System ◽

Economic Perspective ◽

Solar Hydrogen ◽

Alkaline Water

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Genome-Wide Association Studies Based on Equine Joint Angle Measurements Reveal New QTL Affecting the Conformation of Horses

Genes ◽

10.3390/genes10050370 ◽

2019 ◽

Vol 10 (5) ◽

pp. 370 ◽

Cited By ~ 5

Author(s):

Annik Imogen Gmel ◽

Thomas Druml ◽

Rudolf von Niederhäusern ◽

Tosso Leeb ◽

Markus Neuditschko

Keyword(s):

Joint Angle ◽

Association Studies ◽

Genome Wide Association ◽

Cranial Morphology ◽

Genome Wide Association Studies ◽

Joint Angles ◽

Mineral Density ◽

Mixed Effect ◽

Stifle Joint ◽

Genome Wide

The evaluation of conformation traits is an important part of selection for breeding stallions and mares. Some of these judged conformation traits involve joint angles that are associated with performance, health, and longevity. To improve our understanding of the genetic background of joint angles in horses, we have objectively measured the angles of the poll, elbow, carpal, fetlock (front and hind), hip, stifle, and hock joints based on one photograph of each of the 300 Franches-Montagnes (FM) and 224 Lipizzan (LIP) horses. After quality control, genome-wide association studies (GWASs) for these traits were performed on 495 horses, using 374,070 genome-wide single nucleotide polymorphisms (SNPs) in a mixed-effect model. We identified two significant quantitative trait loci (QTL) for the poll angle on ECA28 (p = 1.36 × 10−7), 50 kb downstream of the ALX1 gene, involved in cranial morphology, and for the elbow joint on ECA29 (p = 1.69 × 10−7), 49 kb downstream of the RSU1 gene, and 75 kb upstream of the PTER gene. Both genes are associated with bone mineral density in humans. Furthermore, we identified other suggestive QTL associated with the stifle joint on ECA8 (p = 3.10 × 10−7); the poll on ECA1 (p = 6.83 × 10−7); the fetlock joint of the hind limb on ECA27 (p = 5.42 × 10−7); and the carpal joint angle on ECA3 (p = 6.24 × 10−7), ECA4 (p = 6.07 × 10−7), and ECA7 (p = 8.83 × 10−7). The application of angular measurements in genetic studies may increase our understanding of the underlying genetic effects of important traits in equine breeding.

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Real‐time feedback control of voice in cochlear implant recipients

Laryngoscope Investigative Otolaryngology ◽

10.1002/lio2.481 ◽

2020 ◽

Vol 5 (6) ◽

pp. 1156-1162

Author(s):

Anirudh Gautam ◽

Jason A. Brant ◽

Michael J. Ruckenstein ◽

Steven J. Eliades

Keyword(s):

Feedback Control ◽

Cochlear Implant ◽

Real Time

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Experimental and Numerical Study of Fracture Behavior of Rock-Like Material Specimens with Single Pre-Set Joint under Dynamic Loading

Materials ◽

10.3390/ma14102690 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2690

Author(s):

Bo Pan ◽

Xuguang Wang ◽

Zhenyang Xu ◽

Lianjun Guo ◽

Xuesong Wang

Keyword(s):

Crack Initiation ◽

Crack Propagation ◽

Joint Angle ◽

Simulation Software ◽

Dissipated Energy ◽

Energy Structure ◽

Joint Angles ◽

Crack Penetration ◽

Before And After ◽

The Impact

The Split Hopkinson Pressure Bar (SHPB) is an apparatus for testing the dynamic stress-strain response of the cement mortar specimen with pre-set joints at different angles to explore the influence of joint attitudes of underground rock engineering on the failure characteristics of rock mass structure. The nuclear magnetic resonance (NMR) has also been used to measure the pore distribution and internal cracks of the specimen before and after the testing. In combination with numerical analysis, the paper systematically discusses the influence of joint angles on the failure mode of rock-like materials from three aspects of energy dissipation, microscopic damage, and stress field characteristics. The result indicates that the impact energy structure of the SHPB is greatly affected by the pre-set joint angle of the specimen. With the joint angle increasing, the proportion of reflected energy moves in fluctuation, while the ratio of transmitted energy to dissipated energy varies from one to the other. NMR analysis reveals the structural variation of the pores in those cement specimens before and after the impact. Crack propagation direction is correlated with pre-set joint angles of the specimens. With the increase of the pre-set joint angles, the crack initiation angle decreases gradually. When the joint angles are around 30°–75°, the specimens develop obvious cracks. The crushing process of the specimens is simulated by LS-DYNA software. It is concluded that the stresses at the crack initiation time are concentrated between 20 and 40 MPa. The instantaneous stress curve first increases and then decreases with crack propagation, peaking at different times under various joint angles; but most of them occur when the crack penetration ratio reaches 80–90%. With the increment of joint angles in specimens through the simulation software, the changing trend of peak stress is consistent with the test results.

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RTLIO: Real-Time LiDAR-Inertial Odometry and Mapping for UAVs

Sensors ◽

10.3390/s21123955 ◽

2021 ◽

Vol 21 (12) ◽

pp. 3955

Author(s):

Jung-Cheng Yang ◽

Chun-Jung Lin ◽

Bing-Yuan You ◽

Yin-Long Yan ◽

Teng-Hu Cheng

Keyword(s):

Feedback Control ◽

Real Time ◽

High Frequency ◽

Indoor Environment ◽

Indoor Localization ◽

Sampling Rate ◽

Outdoor Environment ◽

Position Accuracy ◽

Graph Optimization ◽

Pose Graph Optimization

Most UAVs rely on GPS for localization in an outdoor environment. However, in GPS-denied environment, other sources of localization are required for UAVs to conduct feedback control and navigation. LiDAR has been used for indoor localization, but the sampling rate is usually too low for feedback control of UAVs. To compensate this drawback, IMU sensors are usually fused to generate high-frequency odometry, with only few extra computation resources. To achieve this goal, a real-time LiDAR inertial odometer system (RTLIO) is developed in this work to generate high-precision and high-frequency odometry for the feedback control of UAVs in an indoor environment, and this is achieved by solving cost functions that consist of the LiDAR and IMU residuals. Compared to the traditional LIO approach, the initialization process of the developed RTLIO can be achieved, even when the device is stationary. To further reduce the accumulated pose errors, loop closure and pose-graph optimization are also developed in RTLIO. To demonstrate the efficacy of the developed RTLIO, experiments with long-range trajectory are conducted, and the results indicate that the RTLIO can outperform LIO with a smaller drift. Experiments with odometry benchmark dataset (i.e., KITTI) are also conducted to compare the performance with other methods, and the results show that the RTLIO can outperform ALOAM and LOAM in terms of exhibiting a smaller time delay and greater position accuracy.

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