A New Approach to Adaptive Control of Manipulators

1987 ◽  
Vol 109 (3) ◽  
pp. 193-202 ◽  
Author(s):  
H. Seraji
Keyword(s):  
Adaptive Control ◽  
A Priori ◽  
Adaptive Controller ◽  
Operating Point ◽  
Adaptation Algorithm ◽  
New Approach ◽  
Control Scheme ◽  
Auxiliary Signal ◽  
Feedforward Controller ◽  
Parameter Values

The paper presents a new approach to adaptive control of manipulators to achieve trajectory tracking by the joint angles. The central concept in this approach is the utilization of the manipulator “inverse” as a feedforward controller. The desired trajectory is applied as an input to the feedforward controller which “behaves” as the “inverse” of the manipulator at any operating point; and the controller output is used as the driving torque for the manipulator. The controller gains are then updated by an adaptation algorithm derived from MR AC theory to cope with variations in the manipulator inverse due to changes of the operating point. An adaptive feedback controller and an auxiliary signal are also used to enhance closed-loop stability and to achieve faster adaptation. The proposed control scheme is computationally fast and does not require a priori knowledge of the complex dynamic model or the parameter values of the manipulator or the payload. Simulation results are presented in support of the proposed adaptive control scheme. The results demonstrate that the adaptive controller performs remarkably well for different reference trajectories and despite gross variations in the payload.

Bilateral Adaptive Control of Nonlinear Teleoperation Systems With Uncertain Dynamics and Dead-Zone

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Xia Liu ◽  
Mahdi Tavakoli
Keyword(s):  
Adaptive Control ◽  
Function Analysis ◽  
Dead Zone ◽  
Adaptive Controller ◽  
Bilateral Control ◽  
Uncertain Dynamics ◽  
Teleoperation System ◽  
Control Scheme ◽  
Teleoperation Systems ◽  
Dynamic Uncertainties

Dead-zone is one of the most common hard nonlinearities ubiquitous in master–slave teleoperation systems, particularly in the slave robot joints. However, adaptive control techniques applied in teleoperation systems usually deal with dynamic uncertainty but ignore the presence of dead-zone. Dead-zone has the potential to remarkably deteriorate the transparency of a teleoperation system in the sense of position and force tracking performance or even destabilizing the system if not compensated for in the control scheme. In this paper, an adaptive bilateral control scheme is proposed for nonlinear teleoperation systems in the presence of both uncertain dynamics and dead-zone. An adaptive controller is designed for the master robot with dynamic uncertainties and the other is developed for the slave robot with both dynamic uncertainties and unknown dead-zone. The two controllers are incorporated into the four-channel bilateral teleoperation control framework to achieve transparency. The transparency and stability of the closed-loop teleoperation system is studied via a Lyapunov function analysis. Comparisons with the conventional adaptive control which merely deal with dynamic uncertainties in the simulations demonstrate the validity of the proposed approach.

Modelling and Adaptive Control of Tendon-Driven Micromanipulators in the Presence of Van-der-Waals Forces

2004 ◽  
Author(s):  
Athanasios Tsoukalas ◽  
Anthony Tzes
Keyword(s):  
Adaptive Control ◽  
Design Problem ◽  
Van Der Waals ◽  
Adaptive Controller ◽  
Simulation Studies ◽  
Unknown Parameters ◽  
Actuation Mechanism ◽  
Control Scheme ◽  
Driven System ◽  
Adaptive Control Scheme

In this article, the design problem of an adaptive controller for a robotic micromanipulator, including the effects of the applied Van der Waals (VdW) forces is considered. The micro-manipulator’s dynamic model is appropriately modified in order to include the interaction of the attractive VdW-forces. Inhere, every link is decomposed into a series of elementary particles (e.g. spheres), each one interacting with the robot’s neighboring objects during its motion. This interaction induces nonlinear additive terms in the model, attributed to the overall effect of the VdW-forces. The actuation is achieved by a tendon-driven system. At each joint, a pair of tendons is attached and act in an almost passive antagonistic manner. The kinematic and dynamic analysis of the tendon-driven actuation mechanism is offered. Consequently, the microrobot’s model is shown to be linearly parameterizable. Subject to this observation, a globally stabilizable adaptive control scheme is derived, estimating the unknown parameters (masses, generalized VdW-forces) and compensating any variations of those. Simulation studies on a 2-DOF micro-manipulator are offered to highlight the effectiveness of the proposed scheme.

An Adaptively Controlled Electrohydraulic Servo-Mechanism: Part 1: Adaptive Controller Design

1987 ◽  
Vol 201 (3) ◽  
pp. 175-180 ◽  
Author(s):  
K A Edge ◽  
K R A Figueredo
Keyword(s):  
Adaptive Control ◽  
Controller Design ◽  
Control Design ◽  
Adaptive Controller ◽  
Adaptive Control System ◽  
Sampled Data ◽  
Robust Controller ◽  
Servo Mechanism ◽  
Control Scheme ◽  
Model Reference Adaptive

A systematic model reference adaptive control design scheme is presented. The control scheme is developed and analysed within the framework of a sampled data system with a parameter adaptive algorithm designed on the basis of hyper stability theory. A number of supervisory functions are used to supplement the basic adaptive control system in order to enhance robust controller action.

Flutter Suppression of Wind Turbine Blade Using Adaptive Control

2013 ◽  
Author(s):  
Nailu Li ◽  
Mark J. Balas
Keyword(s):  
Adaptive Control ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Adaptive Controller ◽  
Wind Turbine Blade ◽  
Aeroelastic System ◽  
Aerodynamic Loads ◽  
Flutter Suppression ◽  
Control Scheme ◽  
Trailing Edge Flap

The variation of aeroelastic system dynamics is treated as the change of time-varying aerodynamic loads over rotating wind turbine blade. An Adaptive Control scheme is introduced to suppress blade fluttering, caused by unsteady aerodynamic loads, with trailing-edge flap. The robustness and effectiveness of designed Adaptive Controller are shown by good simulation results. For stability analysis, the proposed Adaptive Stability Theorem is proved theoretically by Kalman-Yacubovic Lemma and also illustrated numerically by certain case.

Comparative experiments with a multiple model based adaptive controller for a SCARA type direct drive manipulator

Robotica ◽  
2005 ◽  
Vol 23 (6) ◽  
pp. 721-729 ◽  
Author(s):  
M. Kemal Ciliz ◽  
M. Ömer Tuncay
Keyword(s):  
Adaptive Control ◽  
Nonlinear Effects ◽  
Adaptive Controller ◽  
Control Algorithms ◽  
Robot Arm ◽  
Multiple Model ◽  
Direct Drive ◽  
Test Bed ◽  
Efficient Test ◽  
Control Scheme

In this paper, different adaptive control algorithms will be experimentally tested on a two axis SCARA type direct drive robot arm, and the performance of these algorithms will be compared. Being a direct drive system, the nonlinear effects, arising from the dynamics of the manipulator under high velocities, are directly reflected in the control of the manipulator. This makes the manipulator a more efficient test bed for testing the efficiency of the proposed adaptive schemes. In the experiments, we used fast trajectories rather than slow ones to observe how the proposed controllers compensate the dynamic nonlinear effects of manipulator dynamics. We will test some known adaptive control algorithms given in the literature along with our proposed adaptive control scheme which makes use of multiple models.

An Adaptive Control Scheme for Mechanical Manipulators—Compensation of Nonlinearity and Decoupling Control

1986 ◽  
Vol 108 (2) ◽  
pp. 127-135 ◽  
Author(s):  
Roberto Horowitz ◽  
Masayoshi Tomizuka
Keyword(s):  
Adaptive Control ◽  
Control System ◽  
Adaptive Controller ◽  
Fundamental Properties ◽  
Integral Action ◽  
Control Scheme ◽  
Mechanical Manipulators ◽  
Nonlinear Compensator ◽  
Manipulator Control ◽  
Adaptive Control Scheme

This paper presents a new adaptive control scheme for mechanical manipulators. Making use of the fundamental properties of the manipulator equations, an adaptive algorithm is developed for compensating a nonlinear term in the dynamic equations and for decoupling the dynamic interaction among the joints. A computer simulation study is conducted to evaluate the performance of a manipulator control system composed of the manipulator, adaptive nonlinear compensator/decoupling controller and state feedback controller with integral action. Simulation results show that the manipulator control system with adaptive controller is insensitive to variations of manipulator configurations and payload.

Adaptive Control of Nanowires Motion Using Electric Fields in Fluid Suspension

2019 ◽  
Author(s):  
Juan Wu ◽  
Kaiyan Yu
Keyword(s):  
Adaptive Control ◽  
Electric Fields ◽  
Adaptive Controller ◽  
Experimental Results ◽  
Parametric Uncertainties ◽  
Control Scheme ◽  
Complex Characterization ◽  
Adaptive Control Scheme

Abstract Automated, highly precise manipulation of nanowires and nanotubes is essential to achieve scalable nanomanufacturing. However, nanowires exhibit uncontrolled variations in their structures or compositions that can limit their functions and properties. In this paper, we present an adaptive controller for the simultaneous manipulation of multiple nanowires using electric fields. We then prove its stability in the presence of parametric uncertainties. Without complex characterization of each nanowire’s mobility, the nanowires can be steered to achieve precisely controlled positions. Simulation and experimental results confirm the proposed adaptive control scheme precisely, independently, and simultaneously manipulates the motion of multiple nanowires.

An Robust Adaptive Control Scheme for Hydraulic Servo Systems

2006 ◽  
Author(s):  
Torben Ole Andersen ◽  
Michael Ryygaard Hansen
Keyword(s):  
Adaptive Control ◽  
Tracking Error ◽  
Adaptive Controller ◽  
Robust Adaptive Control ◽  
Region Of Attraction ◽  
Control Scheme ◽  
Whole Space ◽  
Bounded Disturbances ◽  
Robust Adaptive ◽  
Adaptive Control Scheme

The paper looks into Model Reference Adaptive Control (MRAC) based on a linear plant model with constant or slowly varying parameters. The actual plant is non-linear, of a higher model order, subjected to time-varying bounded disturbances, and the measured values may be corrupted by noise. These problems are explored and the adaptive algorithms are modified to counteract instability mechanisms and for improved robustness with respect to bounded disturbances and non-modeled dynamics. The adaptive controller identifies the dominant dynamics and uses feedforward to provide anticipative actions in tracing task while an adaptive feedback part stabilizes the tracking error dynamics. Also the effects of non-modeled high frequency dynamics and bounded disturbances on stability and performance are analyzed. The adaptive control scheme is robust in the sense that it guarantees the existence of a large region of attraction from which all the trajectories remain bounded. The size of the region of attraction depends on the non-modeled dynamics in such a way that if the non-modeled dynamics is infinitely fast, the region of attraction becomes the whole space. Simulation and experimental results are presented and discussed to demonstrate the strength of the proposed algorithm.

scholarly journals A L1 Adaptive Control Scheme for UAV Carrier Landing Using Nonlinear Dynamic Inversion

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Ke Lu ◽  
Chunsheng Liu
Keyword(s):  
Adaptive Control ◽  
Nonlinear Dynamic ◽  
Adaptive Controller ◽  
Dynamic Inversion ◽  
Model Inversion ◽  
L1 Adaptive Control ◽  
Control Scheme ◽  
Glide Slope ◽  
Adaptive Control Scheme ◽  
Nonlinear Dynamic Inversion

This paper presents a L1 adaptive controller augmenting a dynamic inversion controller for UAV (unmanned aerial vehicle) carrier landing. A three axis and a power compensator NDI (nonlinear dynamic inversion) controller serves as the baseline controller for this architecture. The inner-loop command inputs are roll-rate, pitch-rate, yaw-rate, and thrust commands. The outer-loop command inputs come from the guidance law to correct the glide slope. However, imperfect model inversion and nonaccurate aerodynamic data may cause degradation of performance and may lead to the failure of the carrier landing. The L1 adaptive controller is designed as augmentation controller to account for matched and unmatched system uncertainties. The performance of the controller is examined through a Monte Carlo simulation which shows the effectiveness of the developed L1 adaptive control scheme based on nonlinear dynamic inversion.

Adaptive Control of Object Path Tracking and Finger Tip Slippage in a Multi-Fingered Robotic System

2008 ◽  
Author(s):  
Shahram Hadian Jazi ◽  
Mehdi Keshmiri ◽  
Farid Sheikholeslam
Keyword(s):  
Adaptive Control ◽  
System Dynamics ◽  
Trajectory Tracking ◽  
Adaptive Controller ◽  
Path Tracking ◽  
Control Synthesis ◽  
Parameter Uncertainties ◽  
New Approach ◽  
Finger Tip ◽  
Bounded Trajectory

Considering slippage between finger tips and an object, adaptive control synthesis of grasping and manipulating an object by a multi-fingered system is addressed in this paper. Slippage can occur due to many reasons such as disturbances, uncertainties in parameters and dynamics. In this paper, using a novel representation of friction and slippage dynamics, a new approach is introduced to analyze the system dynamics. Then an adaptive controller with a simple update rule is proposed to ensure the bounded trajectory tracking and slippage control, and at the same time to compensate for parameter uncertainties including coefficients of friction. The performance of the proposed adaptive controller is shown analytically and studied numerically.

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