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 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 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.

Design and Implementation of Real-Time CNC Interpolation ASIC for Pythagorean Hodograph Curve Based on FPGA

2011 ◽  
Vol 130-134 ◽  
pp. 3998-4001
Author(s):  
Jing Jie Guo ◽  
Wei Tang ◽  
Xue Ling Wang
Keyword(s):  
Real Time ◽  
Motion Control ◽  
Interpolation Scheme ◽  
Design And Implementation ◽  
Curve Interpolation ◽  
Pythagorean Hodograph ◽  
Stepper Motors ◽  
Cnc Interpolation ◽  
Fpga Chip ◽  
Ph Curve

In this paper, a novel architecture of a real-time CNC interpolation ASIC for Pythagorean Hodograph curve based on FPGA is proposed. The ASIC built on a single FPGA chip contains a NikosⅡprocessor core. It uses a two-stage interpolation scheme to reduce the computational burden of PH curve interpolation. Firstly, the 1st-stage interpolation program is operated on the NikosⅡprocessor. The FPGA hardware logic performs the 2nd-stage interpolation and outputs two groups of pulses for the motion control of actuators (two stepper motors)

scholarly journals Time-Optimal Trajectory Planning for Delta Robot Based on Quintic Pythagorean-Hodograph Curves

IEEE Access ◽  
2018 ◽  
Vol 6 ◽  
pp. 28530-28539 ◽  
Author(s):  
Tingting Su ◽  
Long Cheng ◽  
Yunkuan Wang ◽  
Xu Liang ◽  
Jun Zheng ◽  
...  
Keyword(s):  
Trajectory Planning ◽  
Optimal Trajectory ◽  
Pythagorean Hodograph ◽  
Time Optimal ◽  
Delta Robot ◽  
Optimal Trajectory Planning

scholarly journals Influence of Features on Accuracy of Anomaly Detection for an Energy Trading System

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4237
Author(s):  
Hoon Ko ◽  
Kwangcheol Rim ◽  
Isabel Praça
Keyword(s):  
Anomaly Detection ◽  
Real Time ◽  
Feature Detection ◽  
Trading System ◽  
Judgment Accuracy ◽  
Energy Trading ◽  
Real Time Processing ◽  
Detection Model ◽  
Time Required ◽  
The Relationship

The biggest problem with conventional anomaly signal detection using features was that it was difficult to use it in real time and it requires processing of network signals. Furthermore, analyzing network signals in real-time required vast amounts of processing for each signal, as each protocol contained various pieces of information. This paper suggests anomaly detection by analyzing the relationship among each feature to the anomaly detection model. The model analyzes the anomaly of network signals based on anomaly feature detection. The selected feature for anomaly detection does not require constant network signal updates and real-time processing of these signals. When the selected features are found in the received signal, the signal is registered as a potential anomaly signal and is then steadily monitored until it is determined as either an anomaly or normal signal. In terms of the results, it determined the anomaly with 99.7% (0.997) accuracy in f(4)(S0) and in case f(4)(REJ) received 11,233 signals with a normal or 171anomaly judgment accuracy of 98.7% (0.987).

scholarly journals Adaptive Model for Biofeedback Data Flows Management in the Design of Interactive Immersive Environments

2021 ◽  
Vol 11 (11) ◽  
pp. 5067
Author(s):  
Paulo Veloso Gomes ◽  
António Marques ◽  
João Donga ◽  
Catarina Sá ◽  
António Correia ◽  
...  
Keyword(s):  
Real Time ◽  
Emotional State ◽  
Adaptive Model ◽  
Multimodal Data ◽  
The Real ◽  
Time Interaction ◽  
Data Flows ◽  
Immersive Systems ◽  
Immersive Environment ◽  
The Relationship

The interactivity of an immersive environment comes up from the relationship that is established between the user and the system. This relationship results in a set of data exchanges between human and technological actors. The real-time biofeedback devices allow to collect in real time the biodata generated by the user during the exhibition. The analysis, processing and conversion of these biodata into multimodal data allows to relate the stimuli with the emotions they trigger. This work describes an adaptive model for biofeedback data flows management used in the design of interactive immersive systems. The use of an affective algorithm allows to identify the types of emotions felt by the user and the respective intensities. The mapping between stimuli and emotions creates a set of biodata that can be used as elements of interaction that will readjust the stimuli generated by the system. The real-time interaction generated by the evolution of the user’s emotional state and the stimuli generated by the system allows him to adapt attitudes and behaviors to the situations he faces.

Quantitative analysis of mitral annulus morphology in aortic stenosis using real time 3-dimentional transesophageal echocardiography

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
W Suzuki ◽  
Y Nakano ◽  
H Ohashi ◽  
H Ando ◽  
K Waseda ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Aortic Stenosis ◽  
Transesophageal Echocardiography ◽  
Real Time ◽  
Mitral Annulus ◽  
Left Ventricular Ejection ◽  
Control Group ◽  
The Impact ◽  
The Relationship ◽  
Saddle Shape

Abstract Background Normal mitral annulus morphology is known to be saddle shape. There are a few reports regarding the relationship between flattening of the mitral annular saddle shape and mitral regurgitation. However, the relationship between aortic stenosis (AS) and mitral annulus morphology is unknown. Purpose To assess the impact of AS on mitral annular saddle shape using 3-dimentional transesophageal echocardiography. Methods A total of consecutive 83 subjects including 44 patients with severe AS (AS group) and 39 patients without AS (control group), who underwent real-time 3-dimentional transesophageal echocardiography of the mitral valve, were enrolled. The 3-dimentional geometry of the mitral annulus apparatus was evaluated by the parameters analyzed using dedicated quantification software such as anteroposterior diameter (APD), commissural width (CW), annular height (AH), mitral annulus (MA) area and annular height to commissural width ratio (AHCWR) as shown in Figure. We assessed the impact of severe AS on AHCWR, which is the key parameter showing flattening of the mitral annular saddle shape. These parameters were adjusted by body surface area (BSA). Exclusion criteria included left ventricular ejection fraction <50%, the presence of aortic regurgitation, mitral valve disease, pericardial or congenital diseases, endocarditis, cardiomyopathy, prior myocardial infarction, and paroxysmal or persistent atrial fibrillation. Results Comparisons of mitral valve geometry between AS group and control group are summarized in Table. AH/BSA and AHCWR were significantly lower in AS group compared with control group. Multiple linear regression analysis revealed severe AS to be a significant and independent predictor of lowering AHCWR (β=−0.39, t=−4.04, p<0.001) (adjusted with MA area, selected by stepwise analysis). Conclusions Severe AS might contribute to flattening of the mitral annular saddle shape, lead to the mitral annular structural remodeling. Assessment of the mitral annulus morphology might help evaluating severe AS. Mitral annulus 3-dimensional geometry Funding Acknowledgement Type of funding source: None

scholarly journals AB0867 INCREASED ADIPONECTIN LEVELS ARE ASSOCIATED WITH HIGHER RADIOGRAPHIC SCORES IN THE KNEE JOINT, BUT NOT IN THE HAND JOINT: THE DONG-GU STUDY

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1740.1-1740
Author(s):  
J. H. Kang ◽  
S. E. Choi ◽  
H. Xu ◽  
D. J. Park ◽  
S. S. Lee
Keyword(s):  
Body Mass Index ◽  
Knee Joint ◽  
Body Mass ◽  
Linear Regression Analysis ◽  
Joint Space ◽  
Serum Adiponectin ◽  
Hand Osteoarthritis ◽  
X Rays ◽  
Subchondral Cyst ◽  
The Relationship

Background:Several studies have evaluated the association between serum adiponectin levels and knee and hand osteoarthritis (OA), with mixed results.Objectives:The aim of this study was to investigate the relationship between OA and serum adiponectin levels according to the radiographic features of knee and hand OA.Methods:A total of 2,402 subjects were recruited from the Dong-gu Study. Baseline characteristics were collected via a questionnaire, and X-rays of knee and hand joints were scored by a semi-quantitative grading system. The relationship between serum adiponectin levels and radiographic severity was evaluated by linear regression analysis.Results:Subjects with higher tertiles of serum adiponectin were older and had a lower body mass index than those with lower tertiles. In the knee joint scores, serum adiponectin levels were positively associated with the total score (P<0.001), osteophyte score (P=0.003), and joint space narrowing (JSN) score (P<0.001) among the three tertiles after adjustment for age, sex, body mass index, smoking, alcohol consumption, education, and physical activity. In the hand joint scores, no association was found between serum adiponectin levels and the total score, osteophyte score, JSN score, subchondral cyst score, sclerosis score, erosion score, and malalignment score among the three tertiles after adjustment.Conclusion:In this study, we found that increased adiponectin levels were associated with higher radiographic scores in the knee joint, but not in the hand joint, suggesting different pathophysiologic mechanisms in the development of OA.Disclosure of Interests:None declared

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