On Modeling and to Impact Dynamic Equations of Multi-Rigid-Link Robotics Having Simultaneous Collisions With Frictional Impulses

2006 ◽  
Author(s):  
Xiuping Mu ◽  
Qiong Wu ◽  
Yanping Mu
Keyword(s):  
Robotic Manipulators ◽  
Robotic Systems ◽  
Dynamic Equations ◽  
Impact Dynamics ◽  
Impulsive Forces ◽  
Robotic Manipulations ◽  
Potential Damage ◽  
And Control ◽  
The Impact ◽  
Contact Tasks

Impact plays an important role in robotic manipulations. As robotic manipulators interact with their environment or objects, the motion of the system varies discontinuously and large impulsive forces are created at the surface of contact and are transmitted through the system, particularly when the motion of the manipulator is fast. With the demands for more precise and faster performance of robotic manipulators and minimizing potential damage of the system, being able to better simulate and control impact has become essential. In this paper, the impact dynamics describing simultaneous collisions of multi-link robotics with frictional impulses are investigated. The solutions for the after-impact velocities and impulses are provided in a closed form which can be easily employed for simulating robotic system contact states. The results are also important for the motion planning and impact control of robotic systems with contact tasks.

ON POST-IMPACT ANGULAR VELOCITIES AND RESULTANT IMPULSES WITH RANK-DEFICIENT JACOBIAN MATRICES USING NEWTON IMPACT LAW

2010 ◽  
Vol 02 (03) ◽  
pp. 569-584 ◽  
Author(s):  
XIUPING MU ◽  
CHRISTINE QIONG WU
Keyword(s):  
Closed Form ◽  
Linear Equations ◽  
Contact Problems ◽  
Dynamic Equations ◽  
Jacobian Matrices ◽  
Angular Velocities ◽  
Post Impact ◽  
Velocity Changes ◽  
The Impact ◽  
Contact Tasks

Modeling and trustworthy simulation of impact play an important role in research on robotic contact tasks. Impact dynamic equations, based on Newton impact law, and their solution for planar multi-link robotic collisions have been well developed in literature in the context of determined contact problems. Rank-deficient Jacobian matrices cause the impact equations to be indeterminate. However this issue has not been investigated in previous research. In this paper, the solution for the velocity changes due to impact is proved to be unique in spite of rank-deficient Jacobian matrices and it is solved in a closed form that can be easily employed for simulating robotic system contact states. Furthermore, a set of linear equations with unknown impulses is obtained whereas the impulses can only be solved if extra contact constraints are provided. Two robot collision problems with rank-deficient Jacobian matrices are presented to exemplify the method.

Modeling the impact dynamics of robotic manipulators

1994 ◽  
Vol 27 (14) ◽  
pp. 559-564 ◽  
Author(s):  
G.M. Acaccia ◽  
P.C. Cagetti ◽  
M. Callegari ◽  
R.C. Michelini ◽  
R.M. Molfino
Keyword(s):  
Robotic Manipulators ◽  
Impact Dynamics ◽  
The Impact

Impact Dynamics of Flexible Multibody System Based on Continuous Contact Force Method

2015 ◽  
Vol 744-746 ◽  
pp. 1628-1634
Author(s):  
Yue Chen Duan ◽  
Xia Li ◽  
Wei Wei Zhang ◽  
Guo Ning Liu ◽  
Ting Ting Wang
Keyword(s):  
Contact Force ◽  
Multibody System ◽  
Dynamic Equations ◽  
Impact Dynamics ◽  
Flexible Multibody System ◽  
Flexible Coupling ◽  
Continuous Contact ◽  
Force Method ◽  
Flexible Multibody ◽  
The Impact

The impact dynamics of spatial multi-link flexible multibody system is studied based on the continuous contact force method (CCFM). According to the rigid-flexible coupling dynamic theory of flexible multibody system, the rigid-flexible coupling continuous dynamic equations of the system are established by using the recursive Lagrange method. The impact dynamic equations of the system are stylized derived on the use of CCFM basing on the nonlinear spring-damper model. The contact separation criterion is given to achieve the conversion and calculation of the dynamic model for the system at different stages. An impact dynamic simulation example for a two-link planar flexible multibody system is given, as well as the global dynamic response. The results show that the impact dynamic solving method based on CCFM can be used for the global impact dynamics of multi-link flexible multibody systems. The dynamic behavior of the system changes dramatically during the impact process. The large overall motion, the small deformation motion and the impact effect are coupled.

A Robust Controller of Multi DOF-Cooperating Planar Robotic Manipulators Using a Tuned PID Approach

2014 ◽  
Author(s):  
Dhafar Al-Ani ◽  
Hamed H. Afshari ◽  
Saeid Habibi
Keyword(s):  
Pid Controller ◽  
Equations Of Motion ◽  
Robotic Manipulators ◽  
Robust Controller ◽  
Contact State ◽  
Practical Applications ◽  
Design Values ◽  
End Effectors ◽  
And Control ◽  
The Impact

Usually, a dynamic system with impact conditions is an interesting problem with practical applications in the fields of dynamics, vibrations, and control. One difficulty in controlling robotics (i.e., a multi DOF two-cooperating or two-link planar) is the subject to impact between the end-effectors of manipulators is that the dynamics (i.e., equations of motion) are different when the system status changes suddenly from a non-contact state to a contact state. In this paper, a Tuned PID controller with different design scenarios is developed to regulate the states of two dynamic systems that collide. Further, in this work, three types of errors are used to compare among different cases that are; (1) the steady state error, (2) the root mean square error, and (3) the final value error. The results of the Tuned PID controller are compared to those obtained by a classical PID controller. The PID controller is tuned using the Ziegler–Nicholas approach. The simulation results of the robotic manipulators confirmed the theoretical effectiveness of the proposed controller, based on MATLAB/Simulink. Unlike the classical PID results (i.e., the impact-induced force is found to be 2.0 N), the Tuned PID controller successfully determined the impact-induced force as same as the desired force (i.e., 0.6 N). Moreover, the Tuned PID satisfied all other desired design values.

Suppressed, but Not Forgotten

2011 ◽  
Vol 70 (1) ◽  
pp. 5-11 ◽  
Author(s):  
Beat Meier ◽  
Anja König ◽  
Samuel Parak ◽  
Katharina Henke
Keyword(s):  
Memory Trace ◽  
Thought Suppression ◽  
Test Phase ◽  
Indirect Test ◽  
Final Test ◽  
Test Experiment ◽  
And Control ◽  
Cue Words ◽  
The Impact

This study investigates the impact of thought suppression over a 1-week interval. In two experiments with 80 university students each, we used the think/no-think paradigm in which participants initially learn a list of word pairs (cue-target associations). Then they were presented with some of the cue words again and should either respond with the target word or avoid thinking about it. In the final test phase, their memory for the initially learned cue-target pairs was tested. In Experiment 1, type of memory test was manipulated (i.e., direct vs. indirect). In Experiment 2, type of no-think instructions was manipulated (i.e., suppress vs. substitute). Overall, our results showed poorer memory for no-think and control items compared to think items across all experiments and conditions. Critically, however, more no-think than control items were remembered after the 1-week interval in the direct, but not in the indirect test (Experiment 1) and with thought suppression, but not thought substitution instructions (Experiment 2). We suggest that during thought suppression a brief reactivation of the learned association may lead to reconsolidation of the memory trace and hence to better retrieval of suppressed than control items in the long term.

Research Participation Experiences of Informants of Suicide and Control Cases

Crisis ◽  
2010 ◽  
Vol 31 (5) ◽  
pp. 238-246 ◽  
Author(s):  
Paul W. C. Wong ◽  
Wincy S. C. Chan ◽  
Philip S. L. Beh ◽  
Fiona W. S. Yau ◽  
Paul S. F. Yip ◽  
...  
Keyword(s):  
Ethical Issues ◽  
Research Participation ◽  
Self Report ◽  
Initial Contact ◽  
Psychological Autopsy ◽  
Autopsy Study ◽  
The People ◽  
And Control ◽  
The Impact

Background: Ethical issues have been raised about using the psychological autopsy approach in the study of suicide. The impact on informants of control cases who participated in case-control psychological autopsy studies has not been investigated. Aims: (1) To investigate whether informants of suicide cases recruited by two approaches (coroners’ court and public mortuaries) respond differently to the initial contact by the research team. (2) To explore the reactions, reasons for participation, and comments of both the informants of suicide and control cases to psychological autopsy interviews. (3) To investigate the impact of the interviews on informants of suicide cases about a month after the interviews. Methods: A self-report questionnaire was used for the informants of both suicide and control cases. Telephone follow-up interviews were conducted with the informants of suicide cases. Results: The majority of the informants of suicide cases, regardless of the initial route of contact, as well as the control cases were positive about being approached to take part in the study. A minority of informants of suicide and control cases found the experience of talking about their family member to be more upsetting than expected. The telephone follow-up interviews showed that none of the informants of suicide cases reported being distressed by the psychological autopsy interviews. Limitations: The acceptance rate for our original psychological autopsy study was modest. Conclusions: The findings of this study are useful for future participants and researchers in measuring the potential benefits and risks of participating in similar sensitive research. Psychological autopsy interviews may be utilized as an active engagement approach to reach out to the people bereaved by suicide, especially in places where the postvention work is underdeveloped.

Using Work Domain Analysis to Evaluate the Impact of Digitization on Command and Control

2008 ◽  
Author(s):  
Daniel P. Jenkins ◽  
Neville A. Stanton ◽  
Paul M. Salmon ◽  
Guy H. Walker
Keyword(s):  
Command And Control ◽  
Domain Analysis ◽  
Work Domain Analysis ◽  
And Control ◽  
The Impact ◽  
Work Domain

Experimental Study of the Impact of Alisma plantago-aquatica Secretions on Pathogenic Bacteria

2014 ◽  
Vol 1 (3) ◽  
pp. 3-7
Author(s):  
O. Zhukorskyy ◽  
O. Hulay
Keyword(s):  
Pathogenic Bacteria ◽  
Initial Density ◽  
Biologically Active ◽  
Erysipelothrix Rhusiopathiae ◽  
Natural Focus ◽  
Test Species ◽  
Popula Tions ◽  
And Control ◽  
The Impact

Aim. To estimate the impact of in vivo secretions of water plantain (Alisma plantago-aquatica) on the popula- tions of pathogenic bacteria Erysipelothrix rhusiopathiae. Methods. The plants were isolated from their natural conditions, the roots were washed from the substrate residues and cultivated in laboratory conditions for 10 days to heal the damage. Then the water was changed; seven days later the selected samples were sterilized using fi lters with 0.2 μm pore diameter. The dilution of water plantain root diffusates in the experimental samples was 1:10–1:10,000. The initial density of E. rhusiopathiae bacteria populations was the same for both experimental and control samples. The estimation of the results was conducted 48 hours later. Results. When the dilution of root diffusates was 1:10, the density of erysipelothrixes in the experimental samples was 11.26 times higher than that of the control, on average, the dilution of 1:100 − 6.16 times higher, 1:1000 – 3.22 times higher, 1:10,000 – 1.81 times higher, respectively. Conclusions. The plants of A. plantago-aquatica species are capable of affecting the populations of E. rhusiopathiae pathogenic bacteria via the secretion of biologically active substances into the environment. The consequences of this interaction are positive for the abovementioned bacteria, which is demon- strated by the increase in the density of their populations in the experiment compared to the control. The intensity of the stimulating effect on the populations of E. rhusiopathiae in the root diffusates of A. plantago-aquatica is re- ciprocally dependent on the degree of their dilution. The investigated impact of water plantain on erysipelothrixes should be related to the topical type of biocenotic connections, the formation of which between the test species in the ecosystems might promote maintaining the potential of natural focus of rabies. Keywords: Alisma plantago-aquatica, in vivo secretions, Erysipelothrix rhusiopathiae, population density, topical type of connections.

Changes in the Population Density of Pathogenic Microorganisms in Response to the Allelopathic Effect of Thypha Latifolia

2014 ◽  
Vol 1 (1) ◽  
pp. 31-36 ◽  
Author(s):  
O. Zhukorskiy ◽  
O. Gulay ◽  
V. Gulay ◽  
N. Tkachuk
Keyword(s):  
Cell Density ◽  
Allelopathic Effect ◽  
Pathogenic Microorganisms ◽  
Sterile Water ◽  
Erysipelothrix Rhusiopathiae ◽  
Pathogenic Leptospira ◽  
Favorable Conditions ◽  
And Control ◽  
The Impact ◽  
Control Samples

Aim. To determine the response of the populations of Erysipelothrix rhusiopathiae and Leptospira interrogans pathogenic microorganisms to the impact of broadleaf cattail (Thypha latifolia) root diffusates. Methods. Aqueous solutions of T. latifolia root diffusates were sterilized by vacuum fi ltration through the fi lters with 0.2-micron pore diameter. The experimental samples contained cattail secretions, sterile water, and cultures of E. rhusiopathiae or L. interrogans. The same amount of sterile water, as in the experimental samples, was used for the purpose of control, and the same quantity of microbial cultures was added in it. After exposure, the density of cells in the experimental and control samples was determined. Results. Root diffusates of T. latifolia caused an increase in cell density in the populations of E. rhusiopathiae throughout the whole range of the studied dilutions (1:10–1:10000). In the populations of the 6 studied serological variants of L. interrogans spirochetes (pomona, grippotyphosa, copenhageni, kabura, tarassovi, canicola), the action of broadleaf cattail root diffusates caused the decrease in cell density. A stimulatory effect was marked in the experimental samples of the pollonica serological variant of leptospira. Conclusions. The populations of E. rhusiopathiae and L. interrogans pathogenic microorganisms respond to the allelopathic effect of Thypha latifolia by changing the cell density. The obtained results provide the background to assume that broadleaf cattail thickets create favorable conditions for the existence of E. rhusiopathiae pathogen bacteria. The reduced cell density of L. interrogans in the experimental samples compared to the control samples observed under the infl uence of T. latifolia root diffusates suggests that reservoirs with broadleaf cattail thickets are marked by the unfavorable conditions for the existence of pathogenic leptospira (except L. pollonica).

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