scholarly journals Dynamic manipulation of unknown string by robot arm: realizing momentary string shapes

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Kenta Tabata ◽  
Hiroaki Seki ◽  
Tokuo Tsuji ◽  
Tatsuhiro Hiramitsu ◽  
Masatoshi Hikizu
Keyword(s):  
Parameter Estimation ◽  
High Speed ◽  
Robot Motion ◽  
Robot Arm ◽  
Motion Generation ◽  
Angular Velocities ◽  
Best Parameter ◽  
Mass Spring ◽  
Time Series Images ◽  
Dynamic Manipulation

AbstractWe propose a method to realize the dynamic manipulation of a string with unknown characteristics via a high-speed robot arm. We use a mass-spring-damper model for the string and repeat three steps: motion generation, real manipulation, and parameter estimation. Robot motion is given by the joint angular velocities expressed by the Bezier curves. Their control points are randomly positioned to generate various robot motion for dynamic string manipulation. The generated motion is performed by a wire-driven robot arm and, real string movement is captured by the camera. These time-series images are used for the parameter estimation of string. The best parameter set is determined via comparison between real and simulated string movement after changing parameter randomly and logarithmically. This parameter set is not unique, but it simulates the actual string movement well. Since the estimated string parameter is used for the robot motion generation after repeating the above 3 steps, the motion generation reflects string property and motion objective can success without special tests in advance. This is an advantage of our method because it is difficult to know all of string property with very complicated non-linearity beforehand. We focus on realizing the momentary string shape in 2 dimensions in this paper. We confirmed the effectiveness of our proposed method by realizing five momentary shapes and 3 kinds of string properties. We also discussed the reproducibility and compatibility of estimated parameters and motion generation.

scholarly journals Dynamic manipulation of unknown string by robot arm: Realizing momentary string shapes

2020 ◽  
Author(s):  
Kenta Tabata ◽  
Hiroaki Seki ◽  
Tokuo Tsuji ◽  
Tatsuhiro Hiramitsu ◽  
Masatosh Hikizu
Keyword(s):  
Angular Velocity ◽  
High Speed ◽  
3D Model ◽  
String Model ◽  
Robot Motion ◽  
Robot Arm ◽  
Velocity Data ◽  
Motion Generation ◽  
Motion Data ◽  
Dynamic Manipulation

Abstract In this paper we propose dynamic manipulation for flexible object by using high speed robot arm. We consider dynamic manipulation for unknown string and describe how to manipulete it. Paticulary, we focus on the achived momentary string shapes. For example, momentary string shapes is like a J , C or d. In our strategy for dynamic manipulation of unknown string, manipulation is achieved through repeating 3steps: manipulation of string by robot arm, string parameter estimation. A string is described as the physical-dased 3D model. And ,motion data for robot arm is given as each joint angular velocity data. For simulation of motion, we input the each joint angular velocity data,and initial paramaretars of modeled string.This simulation calculate not only the motion of robot arm but also motion of modeled ropes which occured by robot motion. Parametar estimation is to string parametar by comparing image of the real manipulation with string model and motion generation by estimated model. Repeatly each step, we realize dynamic manipulation of unknown string. Finaly, we show the some experiment of dynamic manipulation ,and we demonstrate effective of parametar estimation and validity.

Adaptive arm motion generation of humanoid robot operating in dynamic environments

2014 ◽  
Vol 41 (2) ◽  
pp. 124-134 ◽  
Author(s):  
Zulkifli Mohamed ◽  
Mitsuki Kitani ◽  
Genci Capi
Keyword(s):  
Humanoid Robot ◽  
Dynamic Environments ◽  
Robot Motion ◽  
Robot Arm ◽  
Objective Functions ◽  
Motion Generation ◽  
Content Type ◽  
Neural Controllers ◽  
Wide Range ◽  
Arm Motion

Purpose – The purpose of this paper is to compare the performance of the robot arm motion generated by neural controllers in simulated and real robot experiments. Design/methodology/approach – The arm motion generation is formulated as an optimization problem. The neural controllers generate the robot arm motion in dynamic environments optimizing three different objective functions; minimum execution time, minimum distance and minimum acceleration. In addition, the robot motion generation in the presence of obstacles is also considered. Findings – The robot is able to adapt its arm motion generation based on the specific task, reaching the goal position in simulated and experimental tests. The same neural controller can be employed to generate the robot motion for a wide range of initial and goal positions. Research limitations/implications – The motion generated yield good results in both simulation and experimental environments. Practical implications – The robot motion is generated based on three different objective functions that are simultaneously optimized. Therefore, the humanoid robot can perform a wide range of tasks in real-life environments, by selecting the appropriate motion. Originality/value – A new method for adaptive arm motion generation of a mobile humanoid robot operating in dynamic human and industrial environments.

scholarly journals Dynamic Manipulation of a Flexible Rope using a High-speed Robot Arm

2013 ◽  
Vol 31 (6) ◽  
pp. 628-638 ◽  
Author(s):  
Yuji Yamakawa ◽  
Akio Namiki ◽  
Masatoshi Ishikawa
Keyword(s):  
High Speed ◽  
Robot Arm ◽  
Dynamic Manipulation

STAND-UP MOTION SUPPORT BY A MOBILE MANIPULATOR SYSTEM WITH HIGH SPEED TACTILE SENSORS

2011 ◽  
Vol 08 (03) ◽  
pp. 181-195
Author(s):  
ZHAOXIAN XIE ◽  
HISASHI YAMAGUCHI ◽  
MASAHITO TSUKANO ◽  
AIGUO MING ◽  
MAKOTO SHIMOJO
Keyword(s):  
Fuzzy Logic ◽  
Feedback Control ◽  
Experimental Verification ◽  
High Speed ◽  
Center Of Pressure ◽  
Tactile Sensor ◽  
Mobile Manipulator ◽  
Tactile Sensing ◽  
Robot Arm ◽  
Tactile Sensors

As one of the home services by a mobile manipulator system, we are aiming at the realization of the stand-up motion support for elderly people. This work is charaterized by the use of real-time feedback control based on the information from high speed tactile sensors for detecting the contact force as well as its center of pressure between the assisted human and the robot arm. First, this paper introduces the design of the tactile sensor as well as initial experimental results to show the feasibility of the proposed system. Moreover, several fundamental tactile sensing-based motion controllers necessary for the stand-up motion support and their experimental verification are presented. Finally, an assist trajectory generation method for the stand-up motion support by integrating fuzzy logic with tactile sensing is proposed and demonstrated experimentally.

Collision analysis and safety evaluation using a collision model for the frontal robot–human impact

Robotica ◽  
2014 ◽  
Vol 33 (7) ◽  
pp. 1536-1550 ◽  
Author(s):  
Jung-Jun Park ◽  
Jae-Bok Song ◽  
Sami Haddadin
Keyword(s):  
Impact Analysis ◽  
Safety Evaluation ◽  
Design Parameters ◽  
Body Parts ◽  
Robot Arm ◽  
Collision Model ◽  
Crash Testing ◽  
Mass Spring ◽  
Head Neck ◽  
Significant Attention

SUMMARYThe safety analysis of human–robot collisions has recently drawn significant attention, as robots are increasingly used in human environments. In order to understand the potential injury a robot could cause in case of an impact, such incidents should be evaluated before designing a robot arm based on biomechanical safety criteria. In recent literature, such incidents have been investigated mostly by experimental crash-testing. However, experimental methods are expensive, and the design parameters of the robot arm are difficult to change instantly. In order to solve this issue, we propose a novel robot-human collision model consisting of a 6-degree-of-freedom mass-spring-damper system for impact analysis. Since the proposed robot-human consists of a head, neck, chest, and torso, the relative motion among these body parts can be analyzed. In this study, collision analysis of impacts to the head, neck, and chest at various collision speeds are conducted using the proposed collision model. Then, the degree of injury is estimated by using various biomechanical severity indices. The reliability of the proposed collision model is verified by comparing the obtained simulation results with experimental results from literature. Furthermore, the basic requirements for the design of safer robots are determined.

scholarly journals Parameter Selection in the Parameter Estimation of Grade Transitions in a Polyethylene Plant

2015 ◽  
Vol 3 (1) ◽  
pp. 1
Author(s):  
Niklas Andersson ◽  
Per-Ola Larsson ◽  
Johan Åkesson ◽  
Niclas Carlsson ◽  
Staffan Skålén ◽  
...  
Keyword(s):  
Parameter Estimation ◽  
Steady State ◽  
State Parameter ◽  
Parameter Selection ◽  
Selection Algorithm ◽  
Parameter Estimations ◽  
Dynamic Case ◽  
Nominal Parameter ◽  
Best Parameter ◽  
Parameter Values

A polyethylene plant at Borealis AB is modelled in the Modelica language and considered for parameter estimations at grade transitions. Parameters have been estimated for both the steady-state and the dynamic case using the JModelica.org platform, which offers tools for steady-state parameter estimation and supports simulation with parameter sensitivies. The model contains 31 candidate parameters, giving a huge amount of possible parameter combinations. The best parameter sets have been chosen using a parameter-selection algorithm that identified parameter sets with poor numerical properties. The parameter-selection algorithm reduces the number of parameter sets that is necessary to explore. The steady-state differs from the dynamic case with respect to parameter selection. Validations of the parameter estimations in the dynamic case show a significant reduction in an objective value used to evaluate the quality of the solution from that of the nominal reference, where the nominal parameter values are used.

scholarly journals Model Adjustment of Small Rotors for High Speed Gas Turbines

1990 ◽  
Author(s):  
Alain Delbez ◽  
Christian Beth ◽  
Daniel Gay
Keyword(s):  
Gas Turbines ◽  
High Speed ◽  
Dynamic Behaviour ◽  
Design Stage ◽  
Rotor Bearing ◽  
Angular Velocities ◽  
Model Adjustment ◽  
Experimental Approaches

In this paper, we present the studies which are carried out at MICROTURBO relating to rotor-bearing systems mounted in small high speed gas turbines. These studies are based on both theoretical and experimental approaches, and are aimed at providing an improved prediction of the dynamic behaviour of rotors at the design stage, in particular the critical angular velocities and sensitivity to unbalance.

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