The Kinematic Model with Three Degrees of Freedom Associated to the Direct Throwing in Basketball Game

2014 ◽  
Vol 658 ◽  
pp. 495-500
Author(s):  
Radu Iacob ◽  
Emil Budescu ◽  
Eugen Merticaru ◽  
Cezar Oprişan
Keyword(s):  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Equation System ◽  
Angular Speed ◽  
The Body ◽  
Movement Speed ◽  
Body Segments ◽  
Geometric Conditions ◽  
Basketball Game ◽  
Three Degrees Of Freedom

The paper presents a reverse kinematic analysis for the free through to basket in order to determine the possible angular movement speed of the arm segments during throw flexion. The body segments offering three freedom degrees to the kinematic model are: the arm, the forearm and the hand. From geometric conditions regarding to the possibility of the ball to get through the basket and the analysis of the parabolic trajectory of the ball, one could determine the mathematical relations for the limitative values of the horizontal and vertical components of the initial velocity and consequently, for the calculation of the initial angle of throwing the ball. On the other hand, from the expression of the flexion movement of the considered body segments, it could be possible to obtain the calculation of the initial throw velocity as functions of the anthropometric data of the analyzed subject, of flexion angles and angular velocity of movement of the body segments. Using some models of functional mathematic analysis, from the two equations with three unknowns, one could determine the variation field of the system solutions. By setting the conditions related to the numeric limits of variation for the angular speed, the numeric field of the possible solutions for the equation system is straitened.

A Model of the Human Spine: Forward and Inverse Kinematics

1992 ◽  
Author(s):  
Sunil Kumar Agrawal ◽  
Siyan Li ◽  
Glen Desmier
Keyword(s):  
Range Of Motion ◽  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Joint Angles ◽  
Human Spine ◽  
Forward And Inverse Kinematics ◽  
Position And Orientation ◽  
Three Degrees Of Freedom ◽  
Adjacent Vertebra

Abstract The human spine is a sophisticated mechanism consisting of 24 vertebrae which are arranged in a series-chain between the pelvis and the skull. By careful articulation of these vertebrae, a human being achieves fine motion of the skull. The spine can be modeled as a series-chain with 24 rigid links, the vertebrae, where each vertebra has three degrees-of-freedom relative to an adjacent vertebra. From the studies in the literature, the vertebral geometry and the range of motion between adjacent vertebrae are well-known. The objectives of this paper are to present a kinematic model of the spine using the available data in the literature and an algorithm to compute the inter vertebral joint angles given the position and orientation of the skull. This algorithm is based on the observation that the backbone can be described analytically by a space curve which is used to find the joint solutions..

scholarly journals Fault-Tolerant Tripod Gait Planning and Verification of a Hexapod Robot

2020 ◽  
Vol 10 (8) ◽  
pp. 2959
Author(s):  
Yiqun Liu ◽  
Xuanxia Fan ◽  
Liang Ding ◽  
Jianfeng Wang ◽  
Tao Liu ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Fault Tolerant ◽  
Kinematic Model ◽  
Stability Margin ◽  
The Body ◽  
Hexapod Robot ◽  
Gait Planning ◽  
Phase Sequence ◽  
Gait Phase ◽  
Tripod Gait

In some hazardous or inaccessible applications, such as earthquake rescue, as a substitute for mankind, robots are expected to perform missions reliably. Unfortunately, the failure of components is difficult to avoid due to the complexity of robot composition and the interference of the environment. Thus, improving the reliability of robots is a crucial problem. The hexapod robot has redundant degrees of freedom due to its multiple joints, making it possible to tolerate the failure of one leg. In this paper, the Fault-Tolerant Tripod (F-TT) gait dealing with the failure of one leg is researched. The Denavit–Hartenberg (D-H) method is exploited to establish a kinematic model for the hexapod robot, the Jacobian matrix is analyzed, and it is proved that the body can be controlled when three legs are supported. Then, an F-TT gait phase sequence planning method based on a stability margin is established, and a method to improve stability is proposed. The trajectory for the center of gravity (COG) and foot is studied. Finally, a simulation model and prototype robot experiments are developed, and the effectiveness of the proposed method is verified.

Sensitivity of Sensor Locations in a Wearable IMU-based Human Activity Recognition System

2021 ◽  
Author(s):  
Mehdi Ejtehadi ◽  
Amin M. Nasrabadi ◽  
Saeed Behzadipour
Keyword(s):  
Activity Recognition ◽  
Human Activity ◽  
Human Subjects ◽  
Kinematic Model ◽  
Recognition System ◽  
Human Activity Recognition ◽  
The Body ◽  
Measurement Unit ◽  
Body Segments ◽  
Body Kinematic

Abstract Background: The advent of Inertial measurement unit (IMU) sensors has significantly extended the application domain of Human Activity Recognition (HAR) systems to healthcare, tele-rehabilitation & daily life monitoring. IMU’s are categorized as body-worn sensors and therefore their output signals and the HAR performance naturally depends on their exact location on the body segments. Objectives: This research aims to introduce a methodology to investigate the effects of misplacing the sensors on the performance of the HAR systems. Methods: The properly placed sensors and their misplaced variations were modeled on a human body kinematic model. The model was then actuated using measured motions from human subjects. The model was then used to run a sensitivity analysis. Results: The results indicated that the transverse misplacement of the sensors on the left arm and right thigh and the rotation of the left thigh sensor significantly decrease the rate of activity recognition. It was also shown that the longitudinal displacements of the sensors (along the body segments) have minor impacts on the HAR performance. A Monte Carlo simulation indicated that if the sensitive sensors are mounted with extra care, the performance can be maintained at a higher than 95% level.Conclusions: Accurate mounting of the IMU’s on the body impacts the performance of the HAR. Particularly, the transverse position and rotation of the IMU’s are more sensitive. The users of such systems need to be informed about the more sensitive sensors and directions to maintain an acceptable performance for the HAR.

Accuracy estimation of a stretch-retractable single section continuum manipulator based on inverse kinematics

2019 ◽  
Vol 46 (5) ◽  
pp. 573-580
Author(s):  
Hao Wang ◽  
GuoHua Gao ◽  
Qixiao Xia ◽  
Han Ren ◽  
LianShi Li ◽  
...  
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Content Type ◽  
Kinematics Model ◽  
Six Degrees Of Freedom ◽  
Single Section ◽  
Motion Range ◽  
Continuum Manipulator ◽  
Three Degrees Of Freedom

Purpose The purpose of this paper is to present a novel stretch-retractable single section (SRSS) continuum manipulator which owns three degrees of freedom and higher motion range in three-dimension workspace than regular single continuum manipulator. Moreover, the motion accuracy was analyzed based on the kinematic model. In addition, the experiments were carried out for validation of the theory. Design/methodology/approach A kinematics model of the SRSS continuum manipulator is presented for analysis on bending, rotating and retracting in its workspace. To discuss the motion accuracy of the SRSS continuum manipulator, the dexterity theory was introduced based on the decomposing of the Jacobian matrix. In addition, the accuracy of motion is estimated based on the inverse kinematics and dexterity theory. To verify the presented theory, the motion of free end was tracked by an electromagnetic positioning system. According to the comparison of experimental value and theoretical analysis, the free end error of SRSS continuum manipulator is less than 6.24 per cent in the region with favorable dexterity. Findings This paper presents a new stretch-retractable continuum manipulator that the structure was composed of several springs as the backbone. Thus, the SRSS continuum manipulator could own wide motion range depending on its retractable structure. Then, the motion accuracy character of the SRSS continuum manipulator in the different regions of its workspace was obtained both theoretically and experimentally. The results show that the high accuracy region distributes in the vicinity of the outer boundary of the workspace. The motion accuracy gradually decreases with the motion position approaching to the center of its workspace. Research limitations/implications The presented SRSS continuum manipulator owns three degrees of freedom. The future work would be focused on the two-section structure which will own six degrees of freedom. Practical implications In this study, the SRSS continuum manipulator could be extended to six degrees of freedom continuum robot with two sections that is less one section than regular six degrees of freedom with three single section continuum manipulator. Originality/value The value of this study is to propose a SRSS continuum manipulator which owns three degrees of freedom and could stretch and retract to expend workspace, for which the accuracy in different regions of the workspace was analyzed and validated based on the kinematics model and experiments. The results could be feasible to plan the motion space of the SRSS continuum manipulator for keeping in suitable accuracy region.

Fabrication and Analysis of a Novel 3 DOF Parallel Wrist Mechanism

1995 ◽  
Vol 117 (2A) ◽  
pp. 343-345 ◽  
Author(s):  
S. K. Agrawal ◽  
Glen Desmier ◽  
Siyan Li
Keyword(s):  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Ohio University ◽  
Three Degrees Of Freedom ◽  
Nominal Position

This paper describes a three-degrees-of-freedom parallel-actuated wrist mechanism developed at Ohio University. This mechanism is capable of pointing an axis within a cone from the nominal position. The mechanism allows unlimited rotation about the pointing axis. Experiments were conducted to validate the kinematic model of the designed wrist.

scholarly journals A Design Concept and Kinematic Model for a Soft Aquatic Robot with Complex Bio-mimicking Motion

2022 ◽  
Author(s):  
Shokoofeh Abbaszadeh ◽  
Roberto Leidhold ◽  
Stefan Hoerner
Keyword(s):  
Degrees Of Freedom ◽  
Kinematic Model ◽  
The Body ◽  
Optical Measurements ◽  
Fish Mortality ◽  
Entire Body ◽  
Animal Testing ◽  
Live Animal ◽  
Complex Deformation ◽  
Propulsion Performance

AbstractFish mortality assessments for turbine passages are currently performed by live-animal testing with up to a hundred thousand fish per year in Germany. A propelled sensor device could act as a fish surrogate. In this context, the study presented here investigates the state of the art via a thorough literature review on propulsion systems for aquatic robots. An evaluation of propulsion performance, weight, size and complexity of the motion achievable allows for the selection of an optimal concept for such a fish mimicking device carrying the sensors. In the second step, the design of a bioinspired soft robotic fish driven by an unconventional drive system is described. It is based on piezoceramic actuators, which allow for motion with five degrees of freedom (DOF) and the creation of complex bio-mimicking body motions. A kinematic model for the motion’s characteristics is developed, to achieve accurate position feedback with the use of strain gauges. Optical measurements validate the complex deformation of the body and deliver the basis for the calibration of the kinematic model. Finally, it can be shown, that the calibrated model presented allows the tracking of the deformation of the entire body with an accuracy of 0.1 mm.

Design and Analysis of a Smart Rehabilitation Walker With Passive Pelvic Mechanism

2020 ◽  
Vol 12 (3) ◽  
Author(s):  
Jiancheng (Charles) Ji ◽  
Shuai Guo ◽  
Fengfeng (Jeff) Xi ◽  
Leigang Zhang
Keyword(s):  
Degrees Of Freedom ◽  
Force Feedback ◽  
Kinematic Model ◽  
The Body ◽  
Community Based ◽  
Community Based Rehabilitation ◽  
Left And Right ◽  
Increasing Demand ◽  
Limb Rehabilitation ◽  
Motion Intention

Abstract In response to the ever-increasing demand of community-based rehabilitation, a novel smart rehab walker iReGo is designed to facilitate the lower limb rehabilitation training based on motion intention recognition. The proposed walker provides a number of passive degrees-of-freedom (DoFs) to the pelvis that are used to smooth the hip rotations in such a way that the natural gait is not significantly affected, meanwhile, three actuated DoFs are actively controlled to assist patients with mobility disabilities. The walker first identifies the user’s motion intention from the interaction forces in both left and right sides of the pelvis and then uses the kinematic model to generate appropriate driving velocities to support the body weight and improve mobility. In this paper, workspace, dexterity, and the force field of the walker are analyzed based on the system Jacobian. Simulation and experiments with healthy subjects are carried out to verify the effectiveness and tip-over stability. These results demonstrate that the walker has sufficient workspace for pelvic motions, satisfactory dexterity, and near-linear force feedback within the prescribed workspace, and that the walker is easily controlled to ensure normal gait.

On Performance Enhancement of Parallel Kinematic Machine

2005 ◽  
Author(s):  
Dan Zhang ◽  
Lihui Wang
Keyword(s):  
Remote Control ◽  
Degrees Of Freedom ◽  
Geometric Model ◽  
Kinematic Model ◽  
Parallel Kinematic Machine ◽  
Web Based ◽  
Remote Manipulation ◽  
Parallel Kinematic ◽  
Moving Platform ◽  
Three Degrees Of Freedom

This paper proposes a spatial three degrees of freedom parallel kinematic machine enhanced by a passive leg and a web-based remote control system. First, the geometric model of the three degrees of freedom parallel kinematic machine is addressed; in the mechanism, a fourth kinematic link — a passive link connecting the base center to the moving platform center — is introduced. This last link is used to constrain the motion of the tool (located in the moving platform) to only three degrees of freedom, as well as to enhance the global stiffness of the structure and distribute the torque from machining. With the kinematic model, a web-based remote control approach is then applied. The concept of the web-based remote manipulation approach is introduced and the principles behind the method are explored in detail. Finally, an example of remote manipulation is demonstrated to the proposed 3-DOF structure using web-based remote control concept before conclusions.

scholarly journals Kinematic-Model-Free Orientation Control for Robot Manipulation Using Locally Weighted Dual Quaternions

Robotics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 76
Author(s):  
Ahmad AlAttar ◽  
Petar Kormushev
Keyword(s):  
Degrees Of Freedom ◽  
Position Control ◽  
Kinematic Model ◽  
Model Learning ◽  
Orientation Control ◽  
Dual Quaternions ◽  
Model Free ◽  
Novel Method ◽  
Model Free Controller ◽  
Three Degrees Of Freedom

Conventional control of robotic manipulators requires prior knowledge of their kinematic structure. Model-learning controllers have the advantage of being able to control robots without requiring a complete kinematic model and work well in less structured environments. Our recently proposed Encoderless controller has shown promising ability to control a manipulator without requiring any prior kinematic model whatsoever. However, this controller is only limited to position control, leaving orientation control unsolved. The research presented in this paper extends the state-of-the-art kinematic-model-free controller to handle orientation control to manipulate a robotic arm without requiring any prior model of the robot or any joint angle information during control. This paper presents a novel method to simultaneously control the position and orientation of a robot’s end effector using locally weighted dual quaternions. The proposed novel controller is also scaled up to control three-degrees-of-freedom robots.

Simulation of water entry of a wedge through free fall in three degrees of freedom

2010 ◽  
Vol 466 (2120) ◽  
pp. 2219-2239 ◽  
Author(s):  
G. D. Xu ◽  
W. Y. Duan ◽  
G. X. Wu
Keyword(s):  
Degrees Of Freedom ◽  
Velocity Potential ◽  
Free Fall ◽  
Water Entry ◽  
Auxiliary Function ◽  
The Body ◽  
Body Motion ◽  
Time Stepping ◽  
The Impact ◽  
Three Degrees Of Freedom

The water entry problem of a wedge through free fall in three degrees of freedom is studied through the velocity potential theory for the incompressible liquid. In particular, the effect of the body rotation is taken into account, which seems to have been neglected so far. The problem is solved in a stretched coordinate system through a boundary element method for the complex potential. The impact process is simulated based on the time stepping method. Auxiliary function method has been used to decouple the mutual dependence between the body motion and the fluid flow. The developed method is verified through results from other simulation and experimental data for some simplified cases. The method is then used to undertake extensive investigation for the free fall problems in three degrees of freedom.

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