Firm Standing for Legged Mobile Manipulators

2004 ◽  
Vol 16 (3) ◽  
pp. 312-318
Author(s):  
Takashi Tagawa ◽  
◽  
Yasumichi Aiyama ◽  
Hisashi Osumi ◽  
Keyword(s):  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Vertical Plane ◽  
Mobile Manipulator ◽  
Mobile Manipulators ◽  
Human Beings ◽  
Hand Force ◽  
Position And Orientation ◽  
Three Dimensional Space

A mobile manipulator generates external force on its hand when it works, making it unable to conduct work accurately because the robot becomes unstable, unlike human beings, who stand stably despite a large hand force acting on their hands. This uses redundant degrees of freedom (DOF) that freely change the body’s position and orientation even if legs are fixed. We focus on a legged robot as a part of locomotion and propose firm standing using a legged mobile manipulator that tolerates greater hand force while maintaining a stable working position. This report proposes firm standing, analyzes it on a two-dimensional vertical plane and in three-dimensional space, and details experiments that demonstrate its feasibility.

Interacting Noise Sources Shape Patterns of Arm Movement Variability in Three-Dimensional Space

2010 ◽  
Vol 104 (5) ◽  
pp. 2654-2666 ◽  
Author(s):  
Gregory A. Apker ◽  
Timothy K. Darling ◽  
Christopher A. Buneo
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Vertical Plane ◽  
Reaching Movements ◽  
Movement Direction ◽  
Dependent Manner ◽  
Movement Variability ◽  
Noise Sources ◽  
Principal Axes ◽  
Three Dimensional Space

Reaching movements are subject to noise in both the planning and execution phases of movement production. The interaction of these noise sources during natural movements is not well understood, despite its importance for understanding movement variability in neurologically intact and impaired individuals. Here we examined the interaction of planning and execution related noise during the production of unconstrained reaching movements. Subjects performed sequences of two movements to targets arranged in three vertical planes separated in depth. The starting position for each sequence was also varied in depth with the target plane; thus required movement sequences were largely contained within the vertical plane of the targets. Each final target in a sequence was approached from two different directions, and these movements were made with or without visual feedback of the moving hand. These combined aspects of the design allowed us to probe the interaction of execution and planning related noise with respect to reach endpoint variability. In agreement with previous studies, we found that reach endpoint distributions were highly anisotropic. The principal axes of movement variability were largely aligned with the depth axis, i.e., the axis along which visual planning related noise would be expected to dominate, and were not generally well aligned with the direction of the movement vector. Our results suggest that visual planning–related noise plays a dominant role in determining anisotropic patterns of endpoint variability in three-dimensional space, with execution noise adding to this variability in a movement direction-dependent manner.

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.

FORCE-UNCONSTRAINED POSES OF THE 3-PRR AND 4-PRR PLANAR PARALLEL MANIPULATORS

2005 ◽  
Vol 29 (4) ◽  
pp. 617-628 ◽  
Author(s):  
Flavio Firmani ◽  
Ron P. Podhorodeski
Keyword(s):  
Parallel Manipulator ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Parallel Manipulators ◽  
Task Space ◽  
Planar Parallel Manipulator ◽  
Order Polynomial ◽  
Position And Orientation ◽  
Planar Parallel Manipulators ◽  
Three Dimensional Space

Force-unconstrained (singular) poses of the 3-PRR planar parallel manipulator (PPM), where the underscore indicates the actuated joint, and the 4-PRR, a redundant PPM with an additional actuated branch, are presented. The solution of these problems is based upon concepts of reciprocal screw quantities and kinematic analysis. In general, non-redundant PPMs such as the 3-PRR are known to have two orders of infinity of force-unconstrained poses, i.e., a three-variable polynomial in terms of the task-space variables (position and orientation of the mobile platform). The inclusion of redundant branches eliminates one order of infinity of force-unconstrained configurations for every actuated branch beyond three. The geometric identification of force-unconstrained poses is carried out by assuming one variable for each order of infinity. In order to simplify the algebraic procedure of these problems, the assumed or “free” variables are considered to be joint displacements. For both manipulators, an effective elimination technique is adopted. For the 3-PRR, the roots of a 6th-order polynomial determine the force-unconstrained poses, i.e., surfaces in a three dimensional space defined by the task-space variables. For the 4-PRR, a 64th-order polynomial determines curves of force-unconstrained poses in the same dimensional space.

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.

scholarly journals Detection and location of surfaces in a 3D environment through a single transducer and ultrasonic spherical caps

2017 ◽  
Vol 37 (3) ◽  
pp. 37-44 ◽  
Author(s):  
Fabio Tomás Moreno-Ortiz ◽  
Eduardo Castillo-Castañeda ◽  
Antonio Hernández-Zavala
Keyword(s):  
Angular Resolution ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Sufficient Information ◽  
Spatial Voting ◽  
True Position ◽  
Spherical Caps ◽  
Position And Orientation ◽  
Voting Method ◽  
Three Dimensional Space

In this paper, an ultrasonic arc map method for flat mapping is extended to three-dimensional space replacing the circumference arcs by spherical caps. An enclosed environment is scanned by employing a single ultrasonic device. The range, position, and orientation of the transducer are used to digitize the uncertainty caps and place them in a three-dimensional map. Through the spatial voting method, the generated voxels are elected in order to distinguish those which mark the true position of an obstacle and discard those that are produced by cross talk, noise, fake ranges, and angular resolution. The results show that it is possible to obtain sufficient information to build a three-dimensional map for navigation by employing inexpensive sensors and a low power data processing.

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 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.

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