A 3D stable trot of a quadruped robot over uneven terrains

2016 ◽  
Vol 231 (3) ◽  
pp. 555-573 ◽  
Author(s):  
Mahdi Khorram ◽  
S Ali A Moosavian
Keyword(s):  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Quadruped Robot ◽  
Legged Robots ◽  
Whole Body ◽  
Main Body ◽  
Stable Gait ◽  
Three Dimensional Space

Legged robots have superior advantages rather than wheeled robots for moving over uneven terrains in the presence of various obstacles. The design of an appropriate path for the main body and legs is an important issue for such robots especially on the uneven terrains. In this paper, the focus is to develop a stable gait for a quadruped robot to trot on uneven terrains. First, a stability condition is developed for a whole-body quadruped robot over uneven terrains based on avoiding the tumbling. By using a simple model, a point with zero moments is calculated in the three-dimensional space. Then, the reference path of this point is determined so that the tumbling moments become zero. The path of the main body will be calculated by using an optimal controller. The main feature of the proposed gait generation framework is that the height of robot can change continuously and stably on uneven terrains. To evaluate the robot stability, the tumbling moments around diagonal lines are calculated and some methods are proposed to reduce these moments to improve the robot stability. The tip of swing foot is also planned to avoid any collision with the environment. The proposed method will be demonstrated using an 18-Degrees of freedom (DOF) quadruped robot in simulation and experimental studies. The experimental setup is a small-size quadruped robot, which is composed of a rectangular plate as its main body with four legs that each one has three active joints with DC servo motors. Obtained results reveal that the robot can trot on uneven terrains stably. Besides, the comparison with the previous methods approves the merits of proposed algorithm on uneven terrains.

Quaternion-Based Algorithm for Direct Kinematic Model of a Kawasaki FS10E Articulated Arm Robot

2015 ◽  
Vol 762 ◽  
pp. 249-254 ◽  
Author(s):  
Stelian Popa ◽  
Alexandru Dorin ◽  
Florin Adrian Nicolescu ◽  
Andrei Mario Ivan
Keyword(s):  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Kinematic Model ◽  
Three Dimensional ◽  
Number System ◽  
Simulation Software ◽  
Six Degrees Of Freedom ◽  
Mathematical Algorithm ◽  
Development And Validation ◽  
Three Dimensional Space

This article follows a detailed description of development and validation for the direct kinematic model of six degrees of freedom articulated arm robot - Kawasaki FS10E model. The development of the kinematic model is based on widely used Denavit-Hartenberg notation, but, after the initial parameter identification, the mathematical algorithm itself follows an approach that uses the quaternion number system, taking advantage of their efficiency in describing spatial rotation - providing a convenient mathematical notation for expressing rotations and orientations of objects in three-dimensional space. The proposed algorithm concludes with two quaternion-based relations that express both the position of robot tool center point (TCP) position and end-effector orientation with respect to robot base coordinate system using Denavit-Hartenberg parameters and joint values as input data. Furthermore, the developed direct kinematic model was validated using the programming and offline simulation software Kawasaki PC Roset.

scholarly journals IMU Action Recognition Based on Machine Learning

2020 ◽  
Vol 3 (6) ◽  
Author(s):  
Yongzhe Zhang ◽  
Jiachen Zheng
Keyword(s):  
Angular Velocity ◽  
Inertial Measurement Unit ◽  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Measurement Unit ◽  
Inertial Measurement ◽  
The Public ◽  
6 Degrees Of Freedom ◽  
Three Dimensional Space

This paper adopts IMU motion recognition technology based on mechanical learning. IMU, inertial measurement unit, is a device that uses accelerometer and gyroscope to measure the three-axis attitude Angle (or angular velocity) and acceleration of an object. In a narrow sense, an IMU is equipped with gyroscope and accelerometer on three orthogonal axes, with a total of 6 degrees of freedom, to measure the angular velocity and acceleration of an object in three-dimensional space, which is known as "6-axis IMU". Broadly speaking, the IMU can add magnetometer to accelerometer and gyroscope to form the "9-axis IMU" which is now known to the public.

Kinematics and Statics for Soft Continuum Manipulators With Heterogeneous Soft Materials

2016 ◽  
Author(s):  
Fei Jiang ◽  
Haijie Zhang ◽  
Jianguo Zhao
Keyword(s):  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Soft Materials ◽  
Initial Study ◽  
Cylindrical Shape ◽  
Continuum Manipulators ◽  
Static Modeling ◽  
Simulation Results ◽  
Three Dimensional Space

Continuum manipulators are continuously bending robots with unlimited number of kinematic degrees of freedom. Most existing continuum manipulators have a central strut made of a single elastic material, and multiple cables placed around the strut are employed to actuate the manipulator. The kinematics for such robots has been extensively studied by assuming the manipulator has a circular shape. In this paper, we aim to investigate the kinematic and static modeling for novel soft continuum manipulators fabricated by multi-material 3D printing with heterogeneous soft materials. We model cylindrical shape manipulators consisting of three sections with three different materials, and they are actuated by three independent cables placed symmetrically. By pulling the cables with different displacements, the manipulators can be bent in three-dimensional space. As our initial study, we employ a single cable for all prototypes. Experimental results are compared with the simulation results to validate the proposed modeling method.

MAP FORMATION IN PROPRIOCEPTIVE CORTEX

1994 ◽  
Vol 05 (02) ◽  
pp. 87-101 ◽  
Author(s):  
SUNGZOON CHO ◽  
JAMES A. REGGIA
Keyword(s):  
Primary Motor Cortex ◽  
Dimensional Space ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Muscle Length ◽  
Muscle Group ◽  
Feature Maps ◽  
Organizational Issues ◽  
Muscle Groups ◽  
Three Dimensional Space

Current understanding of feature maps in proprioceptive cortex is quite limited. To complement experimental studies, we developed a computational model of map formation in proprioceptive cortex. Muscle length and tension from six muscle groups controlling the position of a model arm in three-dimensional space served as input to the simulated cortex. The resultant feature map consisted of regularly spaced clusters of cortical columns representing individual muscle lengths and tensions. Cortical units became tuned to plausible combinations of tension and length, and multiple representations of each muscle group were present. The map was organized such that compact regions within which all muscle group lengths and tensions are represented could be identified. Most striking was the observation that, although not explicitly present in the input, the cortical map developed a representation of the three-dimensional space in which the arm moved. These findings represent testable predictions about proprioceptive cortex, and may also help clarify some organizational issues concerning primary motor cortex.

Adaptations for Controlled Hand Movements in Duchenne’s Muscular Dystrophy

2003 ◽  
Author(s):  
Roscoe C. Bowen ◽  
Rami Seliktar ◽  
Tariq Rahman ◽  
Michael Alexander ◽  
Mena Scavina
Keyword(s):  
Muscular Dystrophy ◽  
Velocity Profile ◽  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Acceleration And Deceleration ◽  
Robotic Orthosis ◽  
The Individual ◽  
Duchenne's Muscular Dystrophy ◽  
Three Dimensional Space

A number of neuropathologies such as Duchenne’s muscular dystrophy (DMD), cause disability in the upper extremity due to the loss of muscle strength. This will eventually prevent the individual from moving their arms in three-dimensional space so it has been proposed that a robotic orthosis could support and augment movement. This orthosis would need to accommodate the movement capabilities of the user. To accomplish this, knowledge of how movements are formed and controlled in the presence of neuromuscular disease needs to be determined. While the arm was supported in a floatation device, DMD subjects were asked to make pointing movements to several targets in the transverse plane. This was done from two start positions while torso movement was constrained and unconstrained. The hand trajectories formed while the torso was constrained were essentially straight but at a cost to the uni-modality of the hand velocity profile. In this configuration the velocity profile contains several phases of acceleration and deceleration producing a multi-modal profile. However, the additional degrees of freedom introduced in the unconstrained torso configuration were employed is such a manner as to produce a smooth uni-modal hand velocity profile.

scholarly journals Piecewise Curve Fitting Based on Least Square Method in 3D Space

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Lihong Xue
Keyword(s):  
Least Squares ◽  
Curve Fitting ◽  
Dimensional Space ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Least Square Method ◽  
Least Square ◽  
Least Square Fitting ◽  
Fitting In ◽  
Three Dimensional Space

Least squares curve fitting is widely used in various neighborhoods, such as industry, agriculture, and economy. The method of piecewise curve fitting is used to deal with some experimental studies with large amounts of data. It can not only be used for plane space points, but also for three-dimensional space points. Firstly, this article introduces the principles of curve fitting and least squares. Secondly, it clarifies the steps based on least square fitting and gives examples of improvements made based on the principle of least square fitting functions by some scientists. Finally, the piecewise curve fitting in the three-dimensional space is obtained using the least squares piecewise curve fitting. It lays a certain theoretical foundation for drawing the laws between data in three-dimensional space.

Determination of Arbitrary Tooth Displacements

1978 ◽  
Vol 57 (5-6) ◽  
pp. 663-674 ◽  
Author(s):  
R.J. Pryputniewicz ◽  
C.J. Burstone ◽  
W.W. Bowley
Keyword(s):  
Dimensional Space ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Double Exposure ◽  
Maxillary Central Incisor ◽  
Modern Technique ◽  
Hologram Interferometry ◽  
Component Loading ◽  
Three Dimensional Space

The noninvasive, modern technique based on the method of double-exposure hologram interferometry was used to measure arbitrary displacements of teeth in the three dimensional space. The experimental studies were carried out on an idealized model of the maxillary central incisor. The results show that the experimental data, based on component loading, are inadequate to accurately predict tooth displacement from an arbitrary force acting in the three dimensional space.

scholarly journals Enhancing Absorption Bandwidth through Vertically Oriented Metamaterials

2019 ◽  
Vol 9 (11) ◽  
pp. 2223 ◽  
Author(s):  
Aaron J. Pung ◽  
Michael D. Goldflam ◽  
D. Bruce Burckel ◽  
Igal Brener ◽  
Michael B. Sinclair ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Ring Resonator ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Split Ring Resonator ◽  
Unit Cell ◽  
Cell Coupling ◽  
Split Ring ◽  
Projection Lithography ◽  
Three Dimensional Space

Metamaterials research has developed perfect absorbers from microwave to optical frequencies, mainly featuring planar metamaterials, also referred to as metasurfaces. In this study, we investigated vertically oriented metamaterials, which make use of the entire three-dimensional space, as a new avenue to widen the spectral absorption band in the infrared regime between 20 and 40 THz. Vertically oriented metamaterials, such as those simulated in this work, can be experimentally realized through membrane projection lithography, which allows a single unit cell to be decorated with multiple resonators by exploiting the vertical dimension. In particular, we analyzed the cases of a unit cell containing a single vertical split-ring resonator (VSRR), a single planar split-ring resonator (PSRR), and both a VSRR and PSRR to explore intra-cell coupling between resonators. We show that the additional degrees of freedom enabled by placing multiple resonators in a unit cell lead to novel ways of achieving omnidirectional super absorption. Our results provide an innovative approach for controlling and designing engineered nanostructures.

A SCHEME FOR SPATIAL WAVE FUNCTION TELEPORTATION IN THREE DIMENSIONS

2006 ◽  
Vol 04 (05) ◽  
pp. 781-790
Author(s):  
O. AKHAVAN ◽  
A. T. REZAKHANI ◽  
M. GOLSHANI
Keyword(s):  
Wave Function ◽  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Quantum Object ◽  
Initial State ◽  
N Level ◽  
Spatial Wave Function ◽  
Three Dimensional Space

We propose a theoretical scheme for teleportation of a general wave function of a quantum object. In principle, this protocol provides teleportation of discrete N-level spatial states of an object with various degrees of freedom, e.g. spin, in ordinary three-dimensional space. All necessary Bell states and their corresponding operators to measure and reconstruct the initial state are represented.

scholarly journals Human Visuospatial Updating After Passive Translations in Three-Dimensional Space

2008 ◽  
Vol 99 (4) ◽  
pp. 1799-1809 ◽  
Author(s):  
Eliana M. Klier ◽  
Bernhard J. M. Hess ◽  
Dora E. Angelaki
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Motor Command ◽  
Body Motion ◽  
Whole Body ◽  
Fixed Target ◽  
Stable Representation ◽  
Vergence Movement ◽  
The Brain ◽  
Three Dimensional Space

To maintain a stable representation of the visual environment as we move, the brain must update the locations of targets in space using extra-retinal signals. Humans can accurately update after intervening active whole-body translations. But can they also update for passive translations (i.e., without efference copy signals of an outgoing motor command)? We asked six head-fixed subjects to remember the location of a briefly flashed target (five possible targets were located at depths of 23, 33, 43, 63, and 150 cm in front of the cyclopean eye) as they moved 10 cm left, right, up, down, forward, or backward while fixating a head-fixed target at 53 cm. After the movement, the subjects made a saccade to the remembered location of the flash with a combination of version and vergence eye movements. We computed an updating ratio where 0 indicates no updating and 1 indicates perfect updating. For lateral and vertical whole-body motion, where updating performance is judged by the size of the version movement, the updating ratios were similar for leftward and rightward translations, averaging 0.84 ± 0.28 (mean ± SD) as compared with 0.51 ± 0.33 for downward and 1.05 ± 0.50 for upward translations. For forward/backward movements, where updating performance is judged by the size of the vergence movement, the average updating ratio was 1.12 ± 0.45. Updating ratios tended to be larger for far targets than near targets, although both intra- and intersubject variabilities were smallest for near targets. Thus in addition to self-generated movements, extra-retinal signals involving otolith and proprioceptive cues can also be used for spatial constancy.

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