Identification of Contact Conditions from Contact Force and Moment - Experimental Verification in Effective Sensing Strategy -

2009 ◽  
Vol 21 (2) ◽  
pp. 236-244 ◽  
Author(s):  
Takayoshi Yamada ◽  
◽  
Tetsuya Mouri ◽  
Akira Tanaka ◽  
Nobuharu Mimura ◽  
...  
Keyword(s):  
Contact Force ◽  
Contact Line ◽  
Contact Conditions ◽  
Contact Type ◽  
Degree Of Separation ◽  
Direction Of Movement ◽  
Force Contact ◽  
The Difference ◽  
Contact Position ◽  
Small Eigenvalues

This paper discusses an effective sensing strategy for identification of contact conditions by using experiments. The contact conditions include contact position, contact force, contact type, direction of contact normal, and direction of contact line. To distinguish contact type more quickly and accurately, we must raise the degree of separation of large and small eigenvalues of a covariance matrix for estimating contact moment. Firstly, several sensing strategies are investigated through experiments. The difference of these strategies is the origin and direction of movement because the contact moment, which expresses the characteristic of contact type, is generated at a contact frame. Secondly, a more effective sensing movement is suggested from experimental results. Finally, it is pointed out that these strategies are related to sensing movement by a human being.

scholarly journals Suppress Vibration on Robotic Polishing with Impedance Matching

Actuators ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 59
Author(s):  
Junjie Dai ◽  
Chin-Yin Chen ◽  
Renfeng Zhu ◽  
Guilin Yang ◽  
Chongchong Wang ◽  
...  
Keyword(s):  
Contact Force ◽  
Force Control ◽  
Impedance Control ◽  
Impedance Matching ◽  
Industrial Robots ◽  
Contact Phase ◽  
Dynamic Tracking ◽  
Force Tracking ◽  
The Difference ◽  
End Effectors

Installing force-controlled end-effectors on the end of industrial robots has become the mainstream method for robot force control. Additionally, during the polishing process, contact force stability has an important impact on polishing quality. However, due to the difference between the robot structure and the force-controlled end-effector, in the polishing operation, direct force control will have impact during the transition from noncontact to contact between the tool and the workpiece. Although impedance control can solve this problem, industrial robots still produce vibrations with high inertia and low stiffness. Therefore, this research proposes an impedance matching control strategy based on traditional direct force control and impedance control methods to improve this problem. This method’s primary purpose is to avoid force vibration in the contact phase and maintain force–tracking performance during the dynamic tracking phase. Simulation and experimental results show that this method can smoothly track the contact force and reduce vibration compared with traditional force control and impedance control.

Analysis of a Ball Bearing With Waviness Considering the Centrifugal Force and Gyroscopic Moment of the Ball

2003 ◽  
Vol 125 (3) ◽  
pp. 487-498 ◽  
Author(s):  
G. H. Jang ◽  
S. W. Jeong
Keyword(s):  
Centrifugal Force ◽  
Contact Force ◽  
Ball Bearing ◽  
Vibration Frequencies ◽  
Governing Equations ◽  
Equilibrium Equations ◽  
Gyroscopic Moment ◽  
Rolling Elements ◽  
Force Contact ◽  
Force Displacement

This research presents an analytical method to calculate the characteristics of the ball bearing under the effect of the waviness in its rolling elements and the centrifugal force and gyroscopic moment of ball. The waviness of rolling elements is modeled by using sinusoidal function, and the centrifugal force and gyroscopic. moment of ball are included in the kinematic constraints and force equilibrium equations to produce the nonlinear governing equations. To improve the convergence of the numerical solution of the nonlinear governing equations, it includes the derivatives of the gyroscopic moment and load-deflection constant of each race in the Newton-Raphson formulation. The accuracy of this research is validated by comparing with the prior research, i.e., (i) the contact force, contact angle in case of considering only the centrifugal force and gyroscopic moment of ball, and (ii) the contact force and vibration frequencies in case of considering only the waviness, respectively. It investigates the stiffness, contact force, displacement and vibration frequencies of the ball bearing, considering not only the centrifugal force and gyroscopic moment of ball but also the waviness of the rolling elements.

scholarly journals Dental malocclusion is not related to temporomandibular joint clicking: a logistic regression analysis in a patient population

2013 ◽  
Vol 84 (2) ◽  
pp. 310-315 ◽  
Author(s):  
Daniele Manfredini ◽  
Giuseppe Perinetti ◽  
Luca Guarda-Nardini
Keyword(s):  
Logistic Regression ◽  
Temporomandibular Joint ◽  
Temporomandibular Disorders ◽  
Temporomandibular Disorder ◽  
Open Bite ◽  
Final Model ◽  
Posterior Crossbite ◽  
The Difference ◽  
Contact Position ◽  
Dental Malocclusion

ABSTRACT Objectives: To assess the association of several dental malocclusion features with temporomandibular joint (TMJ) click sounds in a population of temporomandibular disorder (TMD) patients. Materials and Methods: Four hundred forty-two TMD patients (72% female; 32.2 ± 5.7 years, range 25–44 years) were divided into a TMJ clicking and a no-TMJ clicking group, based on the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) assessment. Seven occlusal features were recorded for each patient: (1) posterior crossbite, (2) overbite, (3) open bite, (4) overjet, (5) mediotrusive and (6) laterotrusive interferences and (7) retruded contact position to maximum intercuspation (RCP-MI) slide length. A logistic regression model was created to estimate the association of occlusal features with TMJ clicking. Results: The difference between the groups as for the prevalence of the various occlusal features was generally not statistically significant, with minor exceptions. Mediotrusive interferences (P  =  .015) and RCP-MI slide ≥2 mm (P  =  .001) were the two occlusal features that were associated with the probability of having TMJ clicking, even if the adjusted odds ratios for TMJ clicking were low for both variables (1.63 and 1.89, respectively). Moreover, the amount of variance in the prevalence of TMJ clicking that was predicted by the final model was as low as 4.5% (R2  =  0.045). Conclusions: Findings from the present investigation suggested that in a population of TMD patients, the contribution of dental malocclusion features to predict TMJ click sounds is minimal with no clinical relevance.

MOVEMENT AND MEMORY FUNCTION IN BIOLOGICAL NEURAL NETWORKS

1995 ◽  
Vol 04 (04) ◽  
pp. 489-500 ◽  
Author(s):  
NAOHIRO ISHII ◽  
KEN-ICHI NAKA
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Spatial Information ◽  
Memory Function ◽  
Amacrine Cells ◽  
Linear Analysis ◽  
Non Linear ◽  
Asymmetric Networks ◽  
Direction Of Movement ◽  
The Difference

Asymmetrical neural networks are shown in the biological neural network as the catfish retina. Horizontal and bipolar cell responses are linearly related to the input modulation of light, while amacrine cells work linearly and nonlinearly in their responses. These cells make asymmetrical neural networks in the retina. Several mechanisms have been proposed for the detection of motion in biological system. To make clear the difference among asymmetrical networks, we applied non-linear analysis developed by N. Wiener. Then, we can derive α-equation of movement, which shows the direction of movement. During the movement, we also can derive the movement equation, which implies that the movement holds regardless of the parameter α. By analyzing the biological asymmetric neural networks, it is shown that the asymmetric networks are excellent in the ability of spatial information processing on the retinal level. Then, the symmetric network was discussed by applying the non-linear analysis. In the symmetric neural network, it was suggested that memory function is needed to perceive the movement.

Implementation of Image Processing in Studying Contact Conditions of Overhead Contact Line-Pantograph at 400 km/h

2020 ◽  
Vol 15 (2) ◽  
pp. 989-995 ◽  
Author(s):  
Kyung-Min Na ◽  
Kiwon Lee ◽  
Hyungchul Kim ◽  
Chul Jin Cho ◽  
Wonseok Choi ◽  
...  
Keyword(s):  
Image Processing ◽  
Contact Line ◽  
Contact Conditions

Visual response properties of neurons in four extrastriate visual areas of the owl monkey (Aotus trivirgatus): a quantitative comparison of medial, dorsomedial, dorsolateral, and middle temporal areas

1981 ◽  
Vol 45 (3) ◽  
pp. 397-416 ◽  
Author(s):  
J. F. Baker ◽  
S. E. Petersen ◽  
W. T. Newsome ◽  
J. M. Allman
Keyword(s):  
Receptive Fields ◽  
Field Size ◽  
Visual Response ◽  
Response Properties ◽  
Middle Temporal ◽  
Optimal Direction ◽  
Visual Areas ◽  
Direction Of Movement ◽  
Owl Monkeys ◽  
The Difference

1. The response properties of 354 single neurons in the medial (M), dorsomedial (DM), dorsolateral (DL), and middle temporal (MT) visual areas were studied quantitatively with bar, spot, and random-dot stimuli in chronically implanted owl monkeys with fixed gaze. 2. A directionality index was computed to compare the responses to stimuli in the optimal direction with the responses to the opposing direction of movement. The greater the difference between opposing directions, the higher the index. MT cells had much higher direction indices to moving bars than cells in DL, DM, and M. 3. A tuning index was computed for each cell to compare the responses to bars moving in the optimal direction, or flashed in the optimal orientation, with the responses in other directions or orientations within +/- 90 degrees. Cells in all four areas were more sharply tuned to the orientation of stationary flashed bars than to moving bars, although a few cells (9/92( were unresponsive in the absence of movement. DM cells tended to be more sharply tuned to moving bars than cells in the other areas. 4. Directionality in DM, DL, and MT was relatively unaffected by the use of single-spot stimuli instead of bars; tuning in all four areas was broader to spots than bars. 5. Moving arrays of randomly spaced spots were more strongly excitatory than bar stimuli for many neurons in MT (16/31 cells). These random-dot stimuli were also effective in M, but evoked no response or weak responses from most cells in DM and DL. 6. The best velocities of movement were usually in the range of 10-100 degrees/s, although a few cells (22/227), primarily in MT (14/69 cells), preferred higher velocities. 7. Receptive fields of neurons in all four areas were much larger than striate receptive fields. Eccentricity was positively correlated with receptive-field size (r = 0.62), but was not correlated with directionality index, tuning index, or best velocity. 8. The results support the hypothesis that there are specializations of function among the cortical visual areas.

Surface-wave damping in a circular cylinder with a fixed contact line

1994 ◽  
Vol 275 ◽  
pp. 285-299 ◽  
Author(s):  
D. M. Henderson ◽  
J. W. Miles
Keyword(s):  
Circular Cylinder ◽  
Contact Line ◽  
Natural Frequencies ◽  
Damping Ratio ◽  
Dominant Mode ◽  
Clean Surface ◽  
Axisymmetric Mode ◽  
Theoretical Predictions ◽  
The Difference ◽  
Stokes Boundary Layers

The natural frequencies and damping ratios for surface waves in a circular cylinder are calculated on the assumptions of a fixed contact line, Stokes boundary layers, and either a clean or a fully contaminated surface. These theoretical predictions are compared with the measurements for the first six modes in a brimfull, sharp-edged cylinder of radius 2.77 cm and depth 3.80 cm. The differences between the predicted and observed frequencies were less than 0.5% for all but the fundamental axisymmetric mode with a clean surface. The difference between the predicted and observed damping ratio for the dominant mode with a clean surface was 20%; this difference was significantly larger for the higher modes with a clean surface and for all of the modes with a contaminated surface.

Wheel-Rail Contact Point Calculation of Flexible Wheelset Base on Wheel-Rail Contact Line Method

2011 ◽  
Vol 105-107 ◽  
pp. 1284-1288
Author(s):  
Hao Gao ◽  
Huan Yun Dai
Keyword(s):  
Contact Line ◽  
Contact Point ◽  
Rolling Circle ◽  
Line Method ◽  
Flexible Wheelset ◽  
Point Calculation ◽  
Coupling Dynamic ◽  
Normal Vectors ◽  
Contact Position ◽  
The Impact

Elastic deformation of wheelset should be considered for wheelset dynamic research. In this article, a new wheel-rail contact point searching algorithm that can be used for flexible wheelset simulation was developed based on wheel-rail contact line method. For given position and deformation of wheelset, normal vectors of a point on each rolling circle and its project on rail were calculated to find out possible contact point, which formed wheel-rail contact line. The final contact point was determined by minimum vertical distance of contact line and rail section profile. Rigid-flexible coupling dynamic equations of single wheelset were established and dynamic simulation was executed. The impact of wheelset deformation on wheel-rail contact position and creepage were discussed. Comparison of rigid and flexible wheelset results show that the new method gets more accurate contact point position.

A Simplified Dynamic Model for the Analysis of the Slider Off-Track Motion Due to Head-Disk Interactions

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Yanhui Yuan ◽  
Shao Wang
Keyword(s):  
Contact Force ◽  
Rotational Speed ◽  
Disk Drive ◽  
Roll Angle ◽  
Transverse Motion ◽  
Transverse Displacement ◽  
Skew Angle ◽  
The Coefficient Of Friction ◽  
The Difference ◽  
Displacement Based

A five-degree-of-freedom model was developed for the analysis of the off-track motion of the magnetic head slider in a hard disk drive. The air bearing was integrated into the dynamic system by combining its stiffness and damping matrices with those of the suspension. Simulation was conducted for the slider in intermittent contact with circumferentially located bumps on a rotating magnetic disk. For a single bump, the excitation to the transverse displacement of the slider is close to that of an impulse. However, for multiple bumps in a sequence, the excitation gives an effect similar to that of a step force function. The maximum transverse displacement increases almost linearly with both the coefficient of friction and the skew angle. The average contact force is determined by the maximum contact force, the contact time ratio, and the shape factor of the contact force, which change with the bump spacing and the rotational speed of the disk. The steady-state transverse displacement is related to the average contact force. As the bump spacing decreases, the average contact force increases, resulting in a greater transverse displacement. Based on the system dynamic characteristics alone, changing the rotational speed of the disk has only a small impact on the average contact force and, thus, on the transverse displacement. At zero skew angle with the bump path close to a rear pad edge, significant transverse motion occurs because of the excited roll mode and the coupling between the roll angle and the transverse displacement. The off-track motion of the slider is dominated by the rotational mode of the actuator arm and the sway mode of the suspension, as verified by comparing the results of the transverse displacement from the 5DOF model to that from a 2DOF model of the transverse motions of the actuator arm and suspension. The effects of the roll angle on the transverse displacement through coupling were found to be responsible for the difference in the transverse displacements obtained from the two models.

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