Micro-Macro or Link-Integrated Micro-Actuator Manipulation: A Kinematics and Dynamics Perspective

2005 ◽  
Author(s):  
J. Zhang ◽  
J. Rastegar
Keyword(s):  
Dynamic Response ◽  
Closed Loop ◽  
Robot Manipulator ◽  
Robot Manipulators ◽  
Active Material ◽  
Kinematics And Dynamics ◽  
Control Problems ◽  
End Effector ◽  
Micro Actuators ◽  
And Control

Smart (active) material based actuators, hereinafter called micro-actuators, have been shown to be well suited for the elimination of high harmonics in joint and/or end-effector motions of the robot manipulators and reduce actuator dynamic response requirements. Low harmonic joint and end-effector motions as well as low actuator dynamic response requirements are essential for a robot manipulator to be capable of operating at high speeds with greater precision and with less vibration and control problems. Micro-actuators may be positioned at the end-effector to obtain a micro and macro robot manipulation. Alternatively, micro-actuators may be integrated into the links to vary a link parameter such as the link length. In this paper, the kinematics and dynamics consequences of each alternative are studies for manipulators with serial and closed-loop chains. It is shown that for the robot manipulator constructed with closed-loop chains, the high harmonic components of all joint motions can be eliminated only when micro-actuators are integrated into the structure of the closed-loop chain links. The latter configuration is also shown to have dynamics advantage over micro and macro configuration. thereby reducing the potential vibration and control problems at higher operating speeds. The conclusions also apply to closed-loop chains of parallel and cooperating robot manipulators.

Micro/Macro or Link-Integrated Micro-actuator Manipulation—A Kinematics and Dynamics Perspective

2006 ◽  
Vol 129 (10) ◽  
pp. 1086-1093 ◽  
Author(s):  
J. Zhang ◽  
J. Rastegar
Keyword(s):  
Dynamic Response ◽  
Closed Loop ◽  
Robot Manipulator ◽  
Robot Manipulators ◽  
High Harmonic ◽  
Kinematics And Dynamics ◽  
Control Problems ◽  
End Effector ◽  
Micro Actuators ◽  
And Control

Smart (active) materials based actuators, hereinafter called micro-actuators, have been shown to be well suited for the elimination of high harmonics in joint and/or end-effector motions of robot manipulators and in the reduction of actuator dynamic response requirements. Low harmonic joint and end-effector motions, as well as low actuator dynamic response requirements, are essential for a robot manipulator to achieve high operating speed and precision with minimal vibration and control problems. Micro-actuators may be positioned at the end-effector to obtain a micro- and macro-robot manipulation configuration. Alternatively, micro-actuators may be integrated into the structure of the links to vary their kinematics parameters, such as their lengths during the motion. In this paper, the kinematics and dynamics consequences of each of the aforementioned alternative are studied for manipulators with serial and closed-loop chains. It is shown that for robot manipulators constructed with closed-loop chains, the high harmonic components of all joint motions can be eliminated only when micro-actuators are integrated into the structure of the closed-loop chain links. The latter configuration is also shown to have dynamics advantage over micro- and macro-manipulator configuration by reducing the potential vibration and control problems at high operating speeds. The conclusions reached in this study also apply to closed-loop chains of parallel and cooperating robot manipulators.

scholarly journals Task Space Trajectory Tracking Control of Robot Manipulators with Uncertain Kinematics and Dynamics

2017 ◽  
Vol 2017 ◽  
pp. 1-19 ◽  
Author(s):  
Xichang Liang ◽  
Yi Wan ◽  
Chengrui Zhang
Keyword(s):  
Time Delay ◽  
Sliding Mode ◽  
Robot Manipulator ◽  
Robot Manipulators ◽  
Time Delay Estimation ◽  
Delay Estimation ◽  
Kinematics And Dynamics ◽  
Task Space ◽  
Terminal Sliding Mode ◽  
Nonsingular Terminal Sliding Mode

To improve the tracking precision of robot manipulators’ end-effector with uncertain kinematics and dynamics in the task space, a new control method is proposed. The controller is based on time delay estimation and combines with the nonsingular terminal sliding mode (NTSM) and adaptive fuzzy logic control scheme. Kinematic parameters are not exactly required with the consideration of kinematic uncertainties in the controller. No dynamic models or numerous parameters of the robot manipulator system are required with the use of TDE. Thus, the controller is simple structure and suitable for practical applications. Furthermore, errors caused by time delay estimation are compensated by the adaptive fuzzy nonsingular terminal sliding mode scheme. The simulation is performed on a 2-DOF robot manipulator with three cases in the task space. The results show that the proposed controller provides faster convergence rate and higher tracking precision than TDE based NTSM and improved TDE based NTSM controller.

Smart Actuator Positioning and Displacement Transmissibility in Serial and Parallel Robot Manipulators for Performance Enhancement

2004 ◽  
Vol 127 (4) ◽  
pp. 589-595 ◽  
Author(s):  
J. Rastegar ◽  
L. Yuan ◽  
J. Zhang
Keyword(s):  
Smart Materials ◽  
Performance Enhancement ◽  
Robot Manipulator ◽  
Robot Manipulators ◽  
High Harmonic ◽  
Harmonic Component ◽  
Operating Speed ◽  
End Effector ◽  
High Harmonics ◽  
Joint Motions

A method is presented for the evaluation of the transmissibility of displacement from smart (active) actuators integrated in the structure of robot manipulators to the manipulator joint and end-effector displacements. The method is based on studying the characteristics of the Jacobian of the mapping function between the two displacements for a given position of the robot manipulator. The developed method provides a tool for the determination of the positioning of smart actuators to provide maximum effectiveness in eliminating high harmonics of the joint or the end-effector motion. In robots with serial and parallel kinematics chains containing nonprismatic joints, due to the associated kinematics nonlinearity, if the joint motions were synthesized with low harmonic trajectories, the end-effector trajectory would still contain high harmonics of the joint motions. Alternatively, if the end-effector motion were synthesized with low harmonic components, due to the inverse kinematics nonlinearity, the actuated joint trajectories would contain a significant high harmonic component. As a result, the operating speed and tracking precision are degraded. By integrating smart materials based actuators in the structure of robot manipulators to provide small amplitude and high frequency motions, the high harmonic component of the actuated joint and/or the end-effector motions can be significantly reduced, thereby making it possible to achieve higher operating speed and tracking precision.

Modeling and control of new model in a spatial coordinates -3D- for cable-based robots

2015 ◽  
Vol 12 (2) ◽  
pp. 189-200 ◽  
Author(s):  
Fouad Inel ◽  
Billel Bouchmal ◽  
Lakhdar Khochmane
Keyword(s):  
Closed Loop ◽  
Geometric Model ◽  
Kinematic Model ◽  
End Effector ◽  
Modeling And Control ◽  
New Model ◽  
Spiral Trajectory ◽  
Spatial Coordinates ◽  
Point To Point ◽  
And Control

This paper presents a modeling and control of new model in a spatial coordinates (x, y, z), from this structures we choose: regular pyramid of a square basis manipulated by five cables and eight cables for a cubic shape. The main objective of this work is to integrate the axe (z) on the horizontal plane (x, y) i-e the plan 3D. This last their intervention especially when we obliged to transfer the end effector from point to point, for that we used the direct and inverse geometric model to study and simulate the end effector position of the robot with five and eight cables. A graphical user interface has been implemented in order to visualizing the position of the robot. Secondly, we present the desired path and determination the tensions and cables lengths of kinematic model required to follow spiral trajectory. At the end, we study the response of our systems in closed loop with a Proportional-Integrated-Derivative (PID) using MATLAB/Simulink which used to verify the performance of the controller.

scholarly journals Saturating Stiffness Control of Robot Manipulators with Bounded Inputs

2017 ◽  
Vol 27 (1) ◽  
pp. 79-90 ◽  
Author(s):  
María del Carmen Rodríguez-Liñán ◽  
Marco Mendoza ◽  
Isela Bonilla ◽  
César A. Chávez-Olivares
Keyword(s):  
Closed Loop ◽  
Robot Manipulator ◽  
Robot Manipulators ◽  
Contact Forces ◽  
Control Law ◽  
Closed Loop System ◽  
Control Scheme ◽  
Lyapunov Stability Analysis ◽  
Stiffness Control ◽  
Three Degree Of Freedom

AbstractA saturating stiffness control scheme for robot manipulators with bounded torque inputs is proposed. The control law is assumed to be a PD-type controller, and the corresponding Lyapunov stability analysis of the closed-loop equilibrium point is presented. The interaction between the robot manipulator and the environment is modeled as spring-like contact forces.The proper behavior of the closed-loop system is validated using a three degree-of-freedom robotic arm.

Inertial and Vision Sensor Based End-Effector Sensing and Control for Robot Manipulators

2010 ◽  
Author(s):  
H. Cheng ◽  
M. Tomizuka
Keyword(s):  
Kalman Filter ◽  
Tracking Control ◽  
Robot Manipulators ◽  
Industrial Robot ◽  
Sampling Rate ◽  
Direct Drive ◽  
End Effector ◽  
Velocity Information ◽  
Accurate Position ◽  
And Control

In the application of industrial robot manipulators, it is often desirable to obtain accurate position and velocity information regarding the end-effector. Estimations based on motor-side encoders alone are often inaccurate due to joint flexibilities and errors in the robot link kinematics. A vision based approach may also be insufficient due to its low sampling rate and image processing and transportation delay. However, with additional accelerometer measurements, a kinematic Kalman filter (KKF) can be formulated to estimate the end-effector motion accurately without encoder signals. The estimation results can be utilized for real time tracking control effectively. In this paper a multirate kinematic Kalman filter (KKF) scheme is formulated using vision and acceleration measurements from the end-effector. Estimations based on the scheme are utilized as feedback signals for tracking control. The effectiveness of the proposed approach is demonstrated by experiments on a single joint direct drive setup.

Optimal Integration of Smart Actuators in the Structure of Serial and Parallel Robot Manipulators to Enhance Speed and Tracking Precision

2003 ◽  
Author(s):  
J. Rastegar ◽  
L. Yuan ◽  
J. Zhang
Keyword(s):  
Robot Manipulator ◽  
Robot Manipulators ◽  
High Harmonic ◽  
Harmonic Component ◽  
Optimal Placement ◽  
Operating Speed ◽  
End Effector ◽  
High Harmonics ◽  
Smart Actuators ◽  
Joint Motions

A method to determine optimal placement of smart (active) materials based actuators in the structure of robot manipulators for the purpose of achieving higher operating speed and tracking precision is developed. The method is based on the evaluation of the transmissibility of the displacement from the integrated smart actuators to the robot manipulator joint and end-effector displacements. By studying the characteristics of the Jacobian of the mapping function between the two displacements for a given position of the robot manipulator, the optimal positioning of the smart actuators that provides maximum effectiveness in eliminating high harmonics of the joint motion or the end-effector motion is determined. In robots with serial and parallel kinematics chains containing non-prismatic joints, due to their associated kinematics nonlinearity, if the joint motions were synthesized with low harmonic trajectories, the end-effector trajectory would contain high harmonics of the joint motions. Alternatively, if the end-effector motion were synthesized with low harmonic motions, due to the inverse kinematics nonlinearity, the actuated joint trajectories would contain a significant high harmonic component. As the result, the operating speed and tracking precision are degraded. By integrating smart materials based actuators in the structure of robot manipulators to provide small amplitude and higher frequency motions, the high harmonic component of the actuated joint and/or the end-effector motions are eliminated. As the result, higher operating speed and tracking precision can be achieved.

Dynamical Resolution of Redundancy for Robot Manipulators

1993 ◽  
Vol 115 (3) ◽  
pp. 592-598 ◽  
Author(s):  
A. Ghosal ◽  
S. Desa
Keyword(s):  
Large Class ◽  
Robot Manipulator ◽  
Robot Manipulators ◽  
Dynamic State ◽  
Redundancy Resolution ◽  
End Effector ◽  
Dynamical Approach ◽  
Pseudo Inverse

A large class of work in the robot manipulator literature deals with the kinematical resolution of redundancy based on the pseudo-inverse of the manipulator Jacobian. In this paper an alternative dynamical approach to redundancy resolution is developed which utilizes the mapping between the actuator torques and the acceleration of the end-effector, at a given dynamic state of the manipulator. The potential advantages of the approach are discussed and an example of a planar 3R manipulator following a circular end-effector trajectory is used to illustrate the proposed approach as well as to compare it with the more well-known approach based on the pseudo-inverse.

scholarly journals A Family of Hyperbolic-Type Explicit Force Regulators with Active Velocity Damping for Robot Manipulators

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Fernando Reyes-Cortés ◽  
César Chávez-Olivares ◽  
Emilio J. González-Galván
Keyword(s):  
Force Control ◽  
Closed Loop ◽  
Robot Manipulator ◽  
Robot Manipulators ◽  
Force Sensor ◽  
Experimental Comparison ◽  
Direct Drive ◽  
New Family ◽  
System Equilibrium ◽  
Control Schemes

This paper addresses the explicit force regulation problem for robot manipulators in interaction tasks. A new family of explicit force-control schemes is presented, which includes a term driven by a large class of saturated-type hyperbolic functions to handle the force error. Also, an active velocity damping term with the purpose of obtaining energy dissipation on the contact surface is incorporated plus compensation for gravity. In order to ensure asymptotic stability of the closed-loop system equilibrium point in Cartesian space, we propose a strict Lyapunov function. A force sensor placed at the end-effector of the robot manipulator is used in order to feed back the measure of the force error in the closed-loop, and an experimental comparison of the performanceL2-norm between 5 explicit force control schemes, which are the classical proportional-derivative (PD), arctangent, and square-root controls and two members of the proposed control family, on a two-degree-of-freedom, direct-drive robot manipulator, is presented.

Uncertainty and Compliance of Robot Manipulators with Applications to Task Feasibility

1991 ◽  
Vol 10 (3) ◽  
pp. 200-213 ◽  
Author(s):  
Dinesh K. Pai ◽  
M.C. Leu
Keyword(s):  
Robot Manipulator ◽  
Robot Manipulators ◽  
Point Contact ◽  
Positive Semidefinite ◽  
Efficient Computation ◽  
Position Uncertainty ◽  
Total Uncertainty ◽  
End Effector ◽  
Work Space ◽  
Compliant Joints

The uncertainty and compliance of a robot manipulator used to perform a task are considered. A formula is derived for the efficient computation of a tight bound on the uncertainty of the end effector, given the uncertainty in the kinematic pa rameters of the robot. It is shown that the total uncertainty is the Minkowski difference of the manipulator uncertainty and the task position uncertainty. Simulations are performed in which the results are used to determine configurations of a robot for which the total uncertainty is within a specified tolerance. The suitability of the compliance of a manipulator for performing a planar peg-in-hole type assembly task is also studied. Manipulators are modeled as having rigid links and compliant joints, following experimental results. It is shown that given any symmetric positive semidefinite compliance, a robot manipulator of the above type can be constructed that will realize this compliance at some point in its work space. A new condition on the stiffness is proposed for preventing jamming. If the peg is supported by the end effector of a robot, we can determine configurations of the robot at which jam ming can be avoided. Simulations are performed to compute the no-jam configurations of a manipulator. The results developed here have direct application to sev eral areas of robotics: determining whether a robotic task is feasible in the presence of uncertainty and joint compliance, choosing work space locations for a robotic task, and the design and selection of robot manipulators. 1. This is called two- point contact in Whitney (1982). 2. That is, errors resulting from both the end-effector and task position uncertainties. 3. The symbol ( ) T denotes the transpose. 4. The half-size of a box is half the length of the box in a specified coordinate direction. 5. Also called the set-sum. 6. The effective compliance refers to the compliance at the peg tip resulting from the compliance of the robot or some other support.

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