Trajectory Planning of Walking With Different Step Lengths of a Seven-Link Biped Robot

2010 ◽  
Author(s):  
A. Fattah ◽  
A. Fakhari
Keyword(s):  
Trajectory Planning ◽  
Polynomial Interpolation ◽  
Biped Robot ◽  
Stable Region ◽  
Dynamics Modeling ◽  
Axis Direction ◽  
Fitness Functions ◽  
Cartesian Space ◽  
Novel Method ◽  
The Impact

Most of the essential parameters of the human walking can be captured with a seven-link planar biped robot. In this paper, dynamics modeling and trajectory planning of a seven-link planar biped robot walking on a level ground with a ditch or stairs are studied. The hip and foot trajectories are designed in Cartesian space using polynomial interpolation such that to vanish the impact effect of feet with ground. The key parameters of the hip joint trajectory in x-axis direction are obtained using boundaries of biped stable region during the walking to satisfy dynamic stability of robot. Then the highest position of the swing foot ankle joint in x and z-axis direction is optimized with two different fitness functions. Next, a novel method for trajectory planning of walking with different step lengths, uses for online trajectory planning, is proposed. Finally, the effectiveness of the proposed method is verified by simulation and experimental results.

scholarly journals Kinematic analysis of a newly designed cable-driven manipulator

2018 ◽  
Vol 42 (2) ◽  
pp. 125-135 ◽  
Author(s):  
Wei Xu ◽  
Yaoyao Wang ◽  
Surong Jiang ◽  
Jiafeng Yao ◽  
Bai Chen
Keyword(s):  
Trajectory Planning ◽  
Kinematic Analysis ◽  
Joint Space ◽  
Joint Angles ◽  
Coupled Motion ◽  
Cartesian Space ◽  
The Impact ◽  
The Relationship

In this paper, the cable routing configurations for a cable-driven manipulator are introduced, and the impact of motion coupling caused by cable transmission routing of a 2n type cable-driven manipulator is analyzed in detail. Based on different configurations of cable routings, the relationship between variation of joint angles and the geometrical sizes of guide pulleys is established, represented by a matrix for coupled motion. Moreover, based on the effects of the motion coupling of a cable-driven manipulator, we propose the condition for the invariance of orientation, which can be achieved constraining of the geometrical sizes of guide pulleys and driven wheels. In addition, to identify the correctness of analysis for coupled motion, a 3-DOFs planer cable-driven manipulator prototyping model is constructed, and the kinematics and trajectory planning has been solved. Finally, the relationship among actuator space, joint space, and Cartesian space, including the mapping of the motion coupling, is experimentally validated. The property of invariance of orientation is also validated by an experiment.

scholarly journals Time-jerk optimal trajectory planning of hydraulic robotic excavator

2021 ◽  
Vol 13 (7) ◽  
pp. 168781402110346
Author(s):  
Yunyue Zhang ◽  
Zhiyi Sun ◽  
Qianlai Sun ◽  
Yin Wang ◽  
Xiaosong Li ◽  
...  
Keyword(s):  
Angular Velocity ◽  
Trajectory Planning ◽  
Optimal Trajectory ◽  
High Efficiency ◽  
Optimal Solution ◽  
Optimal Time ◽  
Target Point ◽  
Robotic Excavator ◽  
The Impact ◽  
Optimal Trajectory Planning

Due to the fact that intelligent algorithms such as Particle Swarm Optimization (PSO) and Differential Evolution (DE) are susceptible to local optima and the efficiency of solving an optimal solution is low when solving the optimal trajectory, this paper uses the Sequential Quadratic Programming (SQP) algorithm for the optimal trajectory planning of a hydraulic robotic excavator. To achieve high efficiency and stationarity during the operation of the hydraulic robotic excavator, the trade-off between the time and jerk is considered. Cubic splines were used to interpolate in joint space, and the optimal time-jerk trajectory was obtained using the SQP with joint angular velocity, angular acceleration, and jerk as constraints. The optimal angle curves of each joint were obtained, and the optimal time-jerk trajectory planning of the excavator was realized. Experimental results show that the SQP method under the same weight is more efficient in solving the optimal solution and the optimal excavating trajectory is smoother, and each joint can reach the target point with smaller angular velocity, and acceleration change, which avoids the impact of each joint during operation and conserves working time. Finally, the excavator autonomous operation becomes more stable and efficient.

Clinical Conundrums When Integrating the QbTest into a Standard ADHD Assessment of Children and Young People

2021 ◽  
Author(s):  
Carsten Vogt
Keyword(s):  
Clinical Practice ◽  
Clinical Decision Making ◽  
Ecological Validity ◽  
Neuropsychological Test ◽  
Real Life ◽  
Clinical Decision ◽  
Hyperactivity Disorder ◽  
Standard Clinical Practice ◽  
Novel Method ◽  
The Impact

AbstractThe uptake of the QbTest in clinical practice is increasing and has recently been supported by research evidence proposing its effectiveness in relation to clinical decision-making. However, the exact underlying process leading to this clinical benefit is currently not well established and requires further clarification. For the clinician, certain challenges arise when adding the QbTest as a novel method to standard clinical practice, such as having the skills required to interpret neuropsychological test information and assess for diagnostically relevant neurocognitive domains that are related to attention-deficit hyperactivity disorder (ADHD), or how neurocognitive domains express themselves within the behavioral classifications of ADHD and how the quantitative measurement of activity in a laboratory setting compares with real-life (ecological validity) situations as well as the impact of comorbidity on test results. This article aims to address these clinical conundrums in aid of developing a consistent approach and future guidelines in clinical practice.

Beyond Interactive Evolution: Expressing Intentions Through Fitness Functions

Leonardo ◽  
2016 ◽  
Vol 49 (3) ◽  
pp. 251-256 ◽  
Author(s):  
Penousal Machado ◽  
Tiago Martins ◽  
Hugo Amaro ◽  
Pedro H. Abreu
Keyword(s):  
Fitness Function ◽  
Interactive Art ◽  
Support Tool ◽  
Generative Art ◽  
Fitness Functions ◽  
Meta Level ◽  
Evolutionary Art ◽  
Creativity Support ◽  
The Creation ◽  
The Impact

Photogrowth is a creativity support tool for the creation of nonphotorealistic renderings of images. The authors discuss its evolution from a generative art application to an interactive evolutionary art tool and finally into a meta-level interactive art system in which users express their artistic intentions through the design of a fitness function. The authors explore the impact of these changes on the sense of authorship, highlighting the range of imagery that can be produced by the system.

A Four Novel Energy Pattern Factor Method for Computation of Weibull Parameter in Impact Strength Reliability of Fibre-Reinforced Concrete

2018 ◽  
Vol 7 (3.12) ◽  
pp. 272
Author(s):  
Gayathri R ◽  
Murali. G ◽  
Parthiban Kathirvel ◽  
Haridharan M.K ◽  
Karthikeyan. K
Keyword(s):  
Reinforced Concrete ◽  
Impact Strength ◽  
Shape Parameter ◽  
Failure Strength ◽  
Fibre Reinforced Concrete ◽  
Test Results ◽  
Weibull Parameter ◽  
Impact Failure ◽  
Novel Method ◽  
The Impact

Impact strength data is a noteworthy factor for designing airport pavements, civilian and military structures etc and it is ought to be modelled precisely. In order to achieve an appropriate modelling data, it is important to select a suitable estimation method. One such commonly used statistical tool is the two parameter Weibull distribution for modelling impact failure strength accurately besides the variations in test results. This study statistically commandsthe variations in the impact failure strength (number of blows to induce failure) of fibre reinforced concrete (FRC) subjected to drop hammer test. Subsequently, a four-different novel method for the computation of Weibull parameter (Shape parameter) based on the earlier researchers test results has been proposed. The accuracy of the proposed four novel method is demonstrated by comparing with power density method and verified with goodness of fit test. Finally, the impact failure strength of FRC is offered in terms of reliability. The proposed four NEPFM is very suitable and efficient to compute the shape parameter in impact failure strength applications. 

Strain Engineering of Thermal Conductivity of Two-Dimensional MoS2 and h-BN

MRS Advances ◽  
2016 ◽  
Vol 1 (32) ◽  
pp. 2297-2302 ◽  
Author(s):  
Xiaonan Wang ◽  
Alireza Tabarraei
Keyword(s):  
Thermal Conductivity ◽  
Tensile Strain ◽  
Phonon Dispersion ◽  
Hexagonal Boron Nitride ◽  
Three Dimensional ◽  
Strain Engineering ◽  
Normal Strain ◽  
Dynamics Modeling ◽  
Molecular Dynamics Modeling ◽  
The Impact

ABSTRACTWe have used reverse nonequlibrium molecular dynamics modeling to study the impact of uniaxial stretching on the thermal conductivity of monolayer molybdenum disulfide (MoS2) and hexagonal boron nitride (h-BN). Our results predict an anomalous response of the thermal conductivity of these materials to normal strain. Thermal conductivity of h-BN increases under a tensile strain whereas thermal conductivity of MoS2 remains fairly constant. These are in striking contrast to the impact of tensile strain on the thermal conductivity of three dimensional materials whose thermal conductivity decreases under tensile strain. We investigate the mechanism responsible for this unexpected behavior by studying the impact of tensile strain on the phonon dispersion curves and group velocities of these materials.

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