Robot Manipulator Vibration Resistance Control Based on Physical Model

2020 ◽  
Author(s):  
Ting-Sheng Chen ◽  
Jen-Yuan (James) Chang
Keyword(s):  
Control Method ◽  
Robot Manipulator ◽  
Path Following ◽  
Position Error ◽  
Machining Accuracy ◽  
Robot Arm ◽  
End Effector ◽  
Vibration Resistance ◽  
Mass Spring ◽  
Accuracy And Repeatability

Abstract The overwhelming manufacturing process with robotic arm has replaced human labors in handling and manufacturing work-pieces in factories. In these years, higher accuracy and repeatability are required for robotic manipulators to perform processes such as welding, deburring and grinding in factories. In these path-following processes, the manipulator’s end-effector often encounter position error caused by its vibrating structures. Therefore, the quality of machining accuracy and surface roughness becomes unstable and unsatisfied. For the purpose of avoiding the vibrations to occur in the robotic manipulator, this study aims to design a control method to reduce vibrations which is divided into two parts, namely (1) dynamic modeling the robot arm by applying modified mass-spring-damper model to each joints and links of the robot arm, and (2) realizing the control of the robot arm’s vibration resistance with predicated dynamics to compensate for the undesired dynamics, respectively. Through the proposed model, the response of each joints in different postures and different payloads applied at the end effector can be fully analyzed and the vibrations can be predicted and compensated. Results with the proposed vibration resistance control method indicate improvement of the model robot arm’s dynamic position error.

On the Problem of Constrained Path Following For Manipulators

1988 ◽  
Vol 110 (4) ◽  
pp. 443-448
Author(s):  
A. Sankaranarayanan ◽  
M. Vidyasagar
Keyword(s):  
Collision Avoidance ◽  
Force Control ◽  
Robot Manipulator ◽  
Sufficient Conditions ◽  
Path Following ◽  
Necessary And Sufficient Conditions ◽  
End Effector ◽  
Circular Contour ◽  
Necessary And Sufficient

Force Control involves moving the end-effector of a robot manipulator on the surface of an object while ensuring that no other part of the manipulator collides with the object. Suppose C is a given contour to be followed. If the end-effector can move between two points a and b on C while meeting the collision avoidance requirement, we can say that a path exists between a and b. We begin by considering a planar manipulator and a circular contour and derive the necessary and sufficient conditions for a path to exist between a pair of points. By extending these ideas, sufficient conditions are derived for a noncircular contour. The advantages of a (kinematically redundant) 3-link planar manipulator over a 2-link manipulator are pointed out. Finally, we consider spatial manipulators and derive the necessary and sufficient conditions for the case where the contour lies on the surface of a sphere.

scholarly journals Structural Design and Material Cutting Using a Laser End Effector on a Robot Arm

TEM Journal ◽  
2020 ◽  
pp. 1455-1459
Author(s):  
Martin Pollák ◽  
Jozef Dobránsky
Keyword(s):  
Structural Design ◽  
Robot Control ◽  
Control Method ◽  
Control Program ◽  
Soft Materials ◽  
Electrical Circuit ◽  
Simulation Software ◽  
Robot Arm ◽  
Software Environment ◽  
End Effector

The paper deals with the structural design of a laser end effector for the arm of the ABB IRB 140 robot which makes products by the laser cutting technology involving soft materials, such as e.g. paper, wood and others. A laser with a power of 1 W was chosen to carry out the cutting. An electrical circuit with a power supply was created for the selected laser; a control method and a structural design of the jig to be attached to the flange of the robot arm were proposed. Subsequently, the robot control program was connected to the control via a computer and the RoboDK simulation software. The paper describes in more detail the creation of the robot control program and the simulation designed in the simulation software environment, as well as the programming of laser control scripts in Python and in the programming environment of Arduino microcontroller.

scholarly journals On the Robot Compliant Motion Control

1989 ◽  
Vol 111 (3) ◽  
pp. 416-425 ◽  
Author(s):  
H. Kazerooni
Keyword(s):  
Control Method ◽  
Robot Manipulator ◽  
Direct Drive ◽  
End Effector ◽  
Compliant Motion ◽  
General Stability ◽  
Dc Motors ◽  
Nonlinear Approach ◽  
Fast Light ◽  
Miniature Robot

The work presented here is a nonlinear approach for the control and stability analysis of manipulative systems in compliant maneuvers. Stability of the environment and the manipulator taken as a whole has been investigated using unstructured models for the dynamic behavior of the robot manipulator and the environment, and a bound for stable manipulation has been derived. We show that for stability of the robot, there must be some initial compliancy either in the robot or in the environment. The general stability condition has been extended to the particular case where the environment is very rigid in comparison with the robot stiffness. A fast, light-weight, active end-effector (a miniature robot) which can be attached to the end-point of large commercial robots has been designed and built to verify the control method. The device is a planar, five-bar linkage which is driven by two direct drive, brush-less DC motors. The control method makes the end-effector to behave dynamically as a two-dimensional, Remote Center Compliance (RCC).

Control of Low-Cost Customizable Robot Arm Actuated by Elastic Tendons

2016 ◽  
Vol 28 (4) ◽  
pp. 509-522 ◽  
Author(s):  
Junki Togashi ◽  
◽  
Kazuhisa Mitobe ◽  
Genci Capi ◽  
Keyword(s):  
Force Control ◽  
Control Method ◽  
Low Cost ◽  
String Tension ◽  
Machining Accuracy ◽  
Robot Arm ◽  
Compliant Joints ◽  
Low Stiffness ◽  
Static Conditions ◽  
The Cost

[abstFig src='/00280004/09.jpg' width='300' text='Elastic tendon driven robot arm' ] This paper presents a low-cost, lightweight robot arm with very low stiffness actuated by elastic tendons. To simplify the string tension control, a new winding device was developed. Small pulleys were incorporated into the winding drum to reduce friction between the tendon and the drum. A marionette-style two-link robot arm with compliant joints was prototyped. Because the arm and winding devices were separate from each other, the cost and weight of the robot were reduced. The links are made with lightweight wood connected by simple shaft joints. The robot design can be easily modified by the user because the mechanical parts do not require high machining accuracy. This robot is intended for implementation in tasks that do not require high positioning accuracy using a simple force control under environmental constraints. Because of its low stiffness, simple and sensor-less force control can be easily implemented based on the relationship between forces under static conditions. The proposed simple control method was evaluated experimentally by conducting position, static force, and hybrid position/force control tasks and was shown to perform well. The results also demonstrate that employing additional sensors, such as a camera, improves the accuracy of the controller.

Shaft Insertion for Moving Object Using Robot Manipulator with Cross PSD and Vibration End-effector

2001 ◽  
Vol 13 (5) ◽  
pp. 450-457 ◽  
Author(s):  
Soichiro Hayakawa ◽  
◽  
Nuio Tsuchida
Keyword(s):  
Error Correction ◽  
High Speed ◽  
Robot Manipulator ◽  
Position Error ◽  
Moving Object ◽  
Position Sensor ◽  
Robot System ◽  
Correct Position ◽  
End Effector ◽  
Vibration Mechanism

We have studied the position sensor with the high speed and precision sensing using a cross PSD. We developed shaft insertion robot for a moving object applying this sensor. For various reasons, position error that can not be avoided between the center of shaft and the center of the sensor occurred. We developed the vibration end-effector to correct this position error. The new end-effector has a vibration mechanism that gives spiral vibration to the shaft, and leads the shaft to a correct position semiactively if shaft insertion fails. This paper shows the improvement of the ability of position error correction by the vibration end-effector for a still object. Using the robot system with this new end-effector, we experimented on shaft insertion for a moving object in various situations. The robot could insert the shaft with a clearance of 50μm at a speed of 80mm/s. The moving velocity of the target doubled compared with our previous system, and the clearance became half.

Kinematic Modeling and Hardware Development of 5-DoF Robot Manipulator

2014 ◽  
Vol 612 ◽  
pp. 51-58
Author(s):  
Kumar Patel Dharmendra ◽  
K. Ramachandra ◽  
Singh Sartaj
Keyword(s):  
Analytical Method ◽  
Inverse Kinematics ◽  
Robot Manipulator ◽  
Robot Arm ◽  
Trigonometric Functions ◽  
Kinematic Modeling ◽  
Positional Accuracy ◽  
End Effector ◽  
Hardware Development ◽  
Articulated Robot

This paper presents a 5-DoF articulated robot manipulator and proposes a strategy for solving its inverse kinematics. The Denavit – Hartenberg (D-H) parameterization has been used to model the kinematics of the manipulator. As degree of freedom of manipulator increases, the geometrical solution for inverse kinematics becomes difficult; hence an analytical method for the same is presented. Novelty in the method presented is that no approximations of trigonometric functions are used resulting in a theoretical positional accuracy of 10-10mm of the end-effector. The articulated robotic manipulator developed makes use of integrated actuators and rapid prototyping technology enabling easy replication for educational purposes. The robot arm has been used for manipulation tasks in its workspace successfully.

scholarly journals End effector position calculation with the ANN for tapping machine

2021 ◽  
Vol 9 (3B) ◽  
Author(s):  
Gullu Akkas ◽  
◽  
Ihsan Korkut ◽  
Murat Tolga Ozkan ◽  
◽  
...  
Keyword(s):  
Artificial Intelligence ◽  
Position Control ◽  
Robot Manipulator ◽  
High Reliability ◽  
Future Research ◽  
Robot Arm ◽  
Labor Costs ◽  
End Effector ◽  
Cartesian Space ◽  
End Point

Nowadays, manufacturers give importance to the production of machines that allow for faster production, reduce labor costs, and minimize operation errors to meet the increasing demand. The search for such machines leads the manufacturing sector to automation. In this study, an automation-supported tapping machine prototype was manufactured. Kinematic equations were used for determining the location of the end effector in Cartesian space, whereas inverse kinematic equations were used for angular positions in joint space relative to positions in Cartesian space. Based on the results of the kinematic equations, the data obtained in certain positions were taught to the system through ANN. The position values for the angles known through the artificial intelligence algorithm were taught to the system. Then, the position coordinates to be reached by this manipulator, which has four degrees of freedom, for the intermediate position coordinate values through artificial neural networks (ANN) have been obtained. It is expected that the device controlled by artificial intelligence will not be affected by the variables in parameter or force changes requiring high working performance. With the control of the positions through ANN, it has been ensured that the position control of the tapping robot manipulator is predicted based on artificial intelligence techniques depending on the angle values of the limbs, and the robot is prevented from going to a position that is on a different trajectory. Accordingly, the robot arm has been made controllable with ANN techniques. With ANN modelling, the position of the end point to perform the tapping process was estimated with high reliability. For future research, a rough simulation was made to see whether the end point would go to a different position in space.

scholarly journals Self-tuning Fuzzy Task Space Controller for Puma 560 Robot

2018 ◽  
Vol 7 (4) ◽  
pp. 273
Author(s):  
Azita Azarfar
Keyword(s):  
High Performance ◽  
Control Method ◽  
Fuzzy Controller ◽  
Robot Manipulator ◽  
Joint Space ◽  
Robot Arm ◽  
Task Space ◽  
Scaling Factors ◽  
Cartesian Space ◽  
Self Tuning

Since in most robot applications the desired paths are determined in task space or Cartesian space, it is important to control the robot arm in task space. In this paper a fuzzy controller with modifiable scaling factors is proposed to control the robot end-effector in task space. The controller is a fuzzy system with a mechanism to change the scaling factors when the error is bounded under a predetermined value. The controller is designed in joint space and is developed to work space by using inverse Jacobian strategy. The simulations results on Puma 560 robot manipulator illustrate the high performance of presented control method.

scholarly journals Dynamic Analysis Of Two Link Robot Manipulator For Control Design Using PID Computed Torque Control.

2016 ◽  
Vol 5 (4) ◽  
pp. 277
Author(s):  
Jolly Atit Shah ◽  
S S Rattan
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Control Method ◽  
Robot Manipulator ◽  
Equation Of Motion ◽  
Torque Control ◽  
Computed Torque Control ◽  
Speed Accuracy ◽  
Accuracy And Repeatability ◽  
Computed Torque

<p>Due to their advantage of high speed, accuracy and repeatability, robot manipulators have become major component of manufacturing industries and even now a days they become part of routine life.            </p><p>Two link robot manipulator is a very basic classical and simple example of robot followed in understanding of basic fundamentals of robotic manipulator. The equation of motion for two link robot is a nonlinear differential equation. For higher degrees of freedom, as the closed form solutions are very difficult we have to use numerical solution. Here we focused mainly on control of robot manipulator to get the desired position using combination of two classical methods PID and computed torque control method after deriving the equation of motion. For the same simulation is represented using MATLAB and compared with computed torque control method.</p>

Motion Planning for a Redundant Robot Manipulator With Stochasticity in Joints

2014 ◽  
Author(s):  
Jaeyeon Lee ◽  
Wooram Park
Keyword(s):  
Stochastic Model ◽  
Motion Planning ◽  
Deterministic Model ◽  
Robot Manipulator ◽  
Robot Arm ◽  
Motion Error ◽  
End Effector ◽  
Redundant Robot ◽  
Planning Step ◽  
Rms Error

This paper concerns generation of motion for a redundant robot manipulator that shows stochastic behavior. Since a deterministic model is not sufficient to represent the motion of such manipulators, a stochastic model should be considered in the motion planning step. While classical approaches for robot control use the motion planning based on the deterministic model and then apply controls (e.g. the feedback control) to compensate the motion error, the new method developed in this paper considers the stochasticity of the system in the planning step for better results in terms of the motion error. This will lower the burden of the controller, resulting in more accurate control. This paper uses the stochastic model for the angle variables of robot joints. This gives the probability density function (pdf) for the position and the orientation of the robot end-effector. The goal of this paper is to find the optimal motion plan that enables the end-effector to follow a reference path with the minimized root-mean-square (RMS) error. To achieve this goal, the cost function that computes the RMS error is defined and then minimized with respect to the target angle values in the joint space. Using simulation of a 4DOF planar robot arm and a 7DOF spatial robot arm, we verify that the suggested method generates better motions than the classical inverse kinematics approach based on the deterministic model.

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