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.

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 Quintic Pythagorean-Hodograph Curves Based Trajectory Planning for Delta Robot with a Prescribed Geometrical Constraint

2019 ◽  
Vol 9 (21) ◽  
pp. 4491 ◽  
Author(s):  
Xu Liang ◽  
Tingting Su
Keyword(s):  
Real Time ◽  
Trajectory Planning ◽  
Joint Space ◽  
Geometrical Constraint ◽  
Planning Approach ◽  
Pythagorean Hodograph ◽  
Delta Robot ◽  
Parameter Dependent ◽  
Ph Curve ◽  
The Relationship

A new trajectory planning approach on the basis of the quintic Pythagorean–Hodograph (PH) curve is presented and applied to Delta robot for implementing pick-and-place operation (PPO). To satisfy a prescribed geometrical constraint, which indicates the distance between the transition segment curve and right angle of PPO trajectory is no greater than a prescribed value, the quintic PH curve is used to produce a connection segment path for collision avoidance. The relationship between the PH curve and constraint is analyzed, based on which PH curve is calculated simply. Afterwards, the trajectory is planned in different phases with different motion laws, i.e. polynomial motion laws and PH curve parameter-dependent motion laws, to obtain a smooth performance both in Cartesian and joint space. The relationship between the PH curve and constraint is also used to improve the efficiency of calculation, and the trajectory symmetry is used to reduce calculation time by direct symmetric transformation. Thus, real-time performance is improved. The results of simulations and experiments indicate that the approach in this paper can provide smooth motion and meet the real-time requirement under the prescribed geometrical constraint.

scholarly journals Research on Real-Time Joint Stiffness Configuration of a Series Parallel Hybrid 7-DOF Humanoid Manipulator in Continuous Motion

2021 ◽  
Vol 11 (5) ◽  
pp. 2433
Author(s):  
Yang Yu ◽  
Shimin Wei ◽  
Haiyan Sheng ◽  
Yingkun Zhang
Keyword(s):  
Real Time ◽  
Human Body ◽  
Joint Stiffness ◽  
Joint Space ◽  
Flexible Joints ◽  
Continuous Motion ◽  
The Real ◽  
Cartesian Space ◽  
Parallel Hybrid ◽  
The Relationship

In this paper, the real-time joint stiffness configuration strategy of a series parallel hybrid 7-DOF (degree of freedom) humanoid manipulator with flexible joints in continuous motion is studied. Firstly, considering the potential human robot accidental collision, combined with the manipulator safety index (MSI) and human body injury thresholds, the motion speed and joint stiffness of the robot are optimized in advance. Secondly, using hyperbolic tangent function for reference, the relationship between joint torques and passive joint deflection angles of the robot is given, which is beneficial for the real-time calculation of joint stiffness and obtain reasonable joint stiffness. Then, the structural model of the selected humanoid manipulator is described, on this basis, the relationship between the joint space stiffness and the Cartesian space stiffness of the humanoid manipulator is analyzed through Jacobian matrix, and the results show that the posture and joint space stiffness of the humanoid manipulator directly affect the Cartesian space stiffness of the humanoid manipulator. Finally, according to whether the humanoid manipulator works in the human-robot interaction environment, the real-time joint stiffness configuration of the humanoid manipulator in continuous motion is simulated and analyzed. The research shows that the humanoid manipulator with flexible joints can adjust the joint stiffness in real-time during continuous motion, and the joint stiffness configuration strategy can effectively improve the safety of human body in human-robot collision. In addition, in application, when the joint space stiffness of the robot is lower, the position accuracy can be improved by trajectory compensation.

Stereotypical Fingertip Trajectories During Grasp

2003 ◽  
Vol 90 (6) ◽  
pp. 3702-3710 ◽  
Author(s):  
D. G. Kamper ◽  
E. G. Cruz ◽  
M. P. Siegel
Keyword(s):  
Logarithmic Spiral ◽  
Joint Space ◽  
Joint Angles ◽  
Object Type ◽  
Cartesian Space ◽  
Reach And Grasp ◽  
Straight Line ◽  
Hand Impairment ◽  
Finger Posture ◽  
Specific Part

The kinematics of movement of all five digits was analyzed during reach-and-grasp tasks for a variety of objects. Ten healthy subjects performed 20 trials involving the grasp of five objects of distinct size and shape. Joint angles were recorded, and digit trajectories were computed using forward kinematics. For a given subject, fingertip trajectories were consistent across trials. The different-sized objects largely produced movement along different portions of a stereotypical trajectory described by a logarithmic spiral. The spirals fit the actual finger positions with a mean error across all trials of 0.23 ± 0.25 cm and accounted for over 98% of the variance in finger position. These patterns were consistent independent of initial finger posture. Subjects did not produce straight-line movements, either in Cartesian space or joint space. The direction of the thumb trajectories exhibited a greater dependence on object type than the finger trajectories, but still utilized a small percentage (<5%) of the available workspace. These results suggest that restoration of a small but specific part of the workspace could have significant impact on function following hand impairment.

Research on Painting Robot Manipulator for Irregular Components in Reproducing Cartridge

2011 ◽  
Vol 121-126 ◽  
pp. 1358-1362
Author(s):  
Qian Qian Chen ◽  
Xiu Ting Wei ◽  
Jiang Hai Lin ◽  
Gang Li
Keyword(s):  
Inverse Problem ◽  
Trajectory Planning ◽  
Degrees Of Freedom ◽  
Robot Manipulator ◽  
Joint Space ◽  
Forward Problem ◽  
Cartesian Space ◽  
Painting Robot

In order to implement the surface painting automation of irregular components of reproducing cartridge, a painting robot manipulator with four degrees of freedom is carried out in this paper. Kinematics forward problem and inverse problem of the manipulator are firstly formulated and then painting trajectory is described by adopting the structure of endpoints and line-style. Furthermore, painting trajectory is generated in both joint space and Cartesian space according to robot’s trajectory planning principle.

Study on Delta Parallel Mechanism Kinematics and Singularity Based on Inverse Solution

2010 ◽  
Vol 43 ◽  
pp. 114-118
Author(s):  
Zhong Jie Chen ◽  
Qui Ju Zhang ◽  
Chun Jian Hua
Keyword(s):  
Optimal Design ◽  
Kinematic Analysis ◽  
Parallel Mechanism ◽  
Jacobian Matrix ◽  
Acceptable Range ◽  
Inverse Solutions ◽  
Singular Configuration ◽  
And Control ◽  
The Impact ◽  
The Relationship

In this paper, the kinematic analysis on a 3-DOF Delta parallel mechanism was carried out and the relationship models between the end cell output motions and the master arms input parameters were established. The forward and inverse solutions to position, velocity and acceleration were deduced and then verified by simulation, the curves that gotten by calculation and simulation were smooth, and no mutations or jumps appeared. In the meantime, based on the kinematic analysis, the impact of Jacobian matrix on the manipulator singular configuration was discussed, and the maneuverability in the reachable space was obtain quantitatively, meanwhile, the value of cond(C(Jv)) was located in the acceptable range, which approached to the isotropic value, so, the theory basis for optimal design was provided. The methods and conclusions in this paper are helpful to the design and control of 3-DOF Delta parallel mechanism.

The Trajectory Planning of Robotic Operation Simulation Based on Virtual Reality

2012 ◽  
Vol 204-208 ◽  
pp. 4729-4733
Author(s):  
Hui Ying Dong ◽  
Qi Hua Sun ◽  
Xue Lu ◽  
Zhang Ming Liu
Keyword(s):  
Virtual Reality ◽  
Trajectory Planning ◽  
Hot Spot ◽  
Joint Space ◽  
Robot Kinematics ◽  
Trajectory Tracking Control ◽  
Cartesian Space ◽  
Robot Trajectory ◽  
Interactive Operation ◽  
Simulation Based

At present, robot simulation based on virtual reality is a hot spot in the study of the robotic. We can build more intuitive and efficient and realistic simulation environment of processing of the robot through combining computer technology and virtual reality technology to carry out a more effective human-machine interactive operation. Robotic trajectory planning is not only the basis of trajectory tracking control, but also the implementation of tasks in robotics. It is discussed trajectory planning and path generation based on robot kinematics and dynamics in the joint space and Cartesian space. In this paper, we study the robot trajectory planning and use three B-spines fitting the robot path in Cartesian space.

Accent Policy and Accent Modification Enterprises as Potential Indicators of Intercultural Power Relations: A Call for an Updated Research Agenda

2013 ◽  
Vol 3 (1) ◽  
pp. 22-33 ◽  
Author(s):  
Brynne D. Ovalle ◽  
Rahul Chakraborty
Keyword(s):  
International Relations ◽  
Identity Construction ◽  
Social Theory ◽  
Power Relations ◽  
Linguistic Diversity ◽  
Cultural Organization ◽  
Using Data ◽  
The Individual ◽  
The Impact ◽  
The Relationship

This article has two purposes: (a) to examine the relationship between intercultural power relations and the widespread practice of accent discrimination and (b) to underscore the ramifications of accent discrimination both for the individual and for global society as a whole. First, authors review social theory regarding language and group identity construction, and then go on to integrate more current studies linking accent bias to sociocultural variables. Authors discuss three examples of intercultural accent discrimination in order to illustrate how this link manifests itself in the broader context of international relations (i.e., how accent discrimination is generated in situations of unequal power) and, using a review of current research, assess the consequences of accent discrimination for the individual. Finally, the article highlights the impact that linguistic discrimination is having on linguistic diversity globally, partially using data from the United Nations Educational, Scientific and Cultural Organization (UNESCO) and partially by offering a potential context for interpreting the emergence of practices that seek to reduce or modify speaker accents.

Business: Making Cents of Coding Systems: Billing for Professional Services

2010 ◽  
Vol 20 (1) ◽  
pp. 3-8
Author(s):  
Dee Adams Nikjeh
Keyword(s):  
Professional Services ◽  
Speech Language Pathology ◽  
Coding Systems ◽  
Language Pathology ◽  
Program Funding ◽  
Fee Schedule ◽  
Procedure Codes ◽  
Relationship Of ◽  
The Impact ◽  
The Relationship

Abstract Administrators and supervisors face daily challenges over issues such as program funding, service fees, correct coding procedures, and the ever-changing healthcare regulations. Receiving equitable reimbursement for speech-language pathology and audiology services necessitates an understanding of federal coding and reimbursement systems. This tutorial provides information pertaining to two major healthcare coding systems and explains the relationship of these systems to clinical documentation, the Medicare Physician Fee Schedule and equitable reimbursement. An explanation of coding edits and coding modifiers is provided for use in those occasional atypical situations when the standard use of procedural coding may not be appropriate. Also included in this tutorial is a brief discussion of the impact that the Medicare Improvements for Patients and Providers Act of 2008 (HR 6331 Medicare Improvements for Patients and Providers Act [MIPPA], 2008) has had on the valuation of speech-language pathology procedure codes.

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