Asymptotic Impact Control of Hydraulic Actuators With Friction

2004 ◽  
Author(s):  
P. Sekhavat ◽  
N. Sepehri ◽  
Q. Wu
Keyword(s):  
Steady State ◽  
Nonlinear Control ◽  
Dry Friction ◽  
Position Control ◽  
Past Research ◽  
Hydraulic Actuator ◽  
Stick Slip ◽  
Hydraulic Actuators ◽  
Control Scheme ◽  
Control Schemes

The focus of this work is stabilization of hydraulic actuators during the transition from free motion to constraint motion and regulating the intermediate impacts that could drive the system unstable. In our past research, we introduced Lyapunov-based nonlinear control schemes capable of fulfilling the above goal by resting the implement on the surface of the environment before starting the sustained-contact motion. The hydraulic actuator’s stick-slip friction effect was, however, either not included in the analysis or not compensated by the control action. In this paper, the application of our previously introduced friction compensating position control scheme is extended to impact regulation of a hydraulic actuator. Theoretical solution and stability analyses as well as actual experiments prove that such control scheme is also effective for asymptotic impact control (with no position steady-state error) of hydraulic actuators in the presence of actuator’s dry friction.

Position-Mode Haptic-Based Control of Teleoperated Hydraulic Actuators

2011 ◽  
Author(s):  
Kurosh Zarei-nia ◽  
Nariman Sepehri
Keyword(s):  
Invariant Set ◽  
Haptic Device ◽  
Position Tracking ◽  
Good Position ◽  
View Point ◽  
Hydraulic Actuator ◽  
Control Laws ◽  
Hydraulic Actuators ◽  
Control Scheme ◽  
On Line

A control scheme for teleoperation of hydraulic actuators, using a haptic device, is developed and experimentally evaluated in this paper. In the control laws, the position error between the displacement of the haptic device and the hydraulic actuator movement is used at both master and slave sides to maintain good position tracking at the actuator side while providing a haptic force to the operator. Lyapunov’s stability theory and LaSalle’s invariant set theorems are employed to prove the asymptotic stability of the system. It is shown that beside stability, the system performs well in terms of position tracking of the hydraulic actuator and providing a feel of telepresence to the operator. Proposed controller only needs system’s pressures and displacements that are easy to obtain via on-line measurements. Additionally, the controller does not need any information about the parameters of the system. These characteristics make the controller very attractive from the implementation view point.

scholarly journals Active Disturbance Rejection Position Synchronous Control of Dual-Hydraulic Actuators with Unknown Dead-Zones

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6124
Author(s):  
Lixin Wang ◽  
Dingxuan Zhao ◽  
Fucai Liu ◽  
Qian Liu ◽  
Zhuxin Zhang
Keyword(s):  
Disturbance Rejection ◽  
Position Control ◽  
Dead Zone ◽  
Lyapunov Theory ◽  
Least Square ◽  
Synchronization Control ◽  
Hydraulic Actuator ◽  
Dead Zones ◽  
Hydraulic Actuators ◽  
Active Disturbance Rejection

In this paper, an integrated control strategy of position synchronization control for dual-electro-hydraulic actuators with unknown dead-zones is proposed. The unified control scheme consists of two parts: One is adaptive dead-zone inverse controllers of each hydraulic actuator to offset the unknown dead-zones. The other is the linear active disturbance rejection controller (LADRC) for position synchronization error. First, the model of the electro-hydraulic proportional position control system (EPPS) was identified by the forgetting factor recursive least square (FFRLS) algorithm. Next, the model reference dead-zone inverse adaptive controller (MRDIAC) was developed to compensate for the delay of actuator response caused by unknown proportional valve dead-zones. Meanwhile, the validity of the adaptive law was proven by the Lyapunov theory. Therefore, the position control accuracy of each hydraulic actuator is guaranteed. Besides, to improve the precision of position synchronization control of dual-hydraulic actuators, a simple and elegant synchronous error-based LADRC was adopted, which applies the total disturbances design concept to eliminate and compensate for motion coupling rather than cross-coupling technology. The performance of the proposed control solution was investigated through extensive comparative experiments based on a hydraulic test platform. The experimental results successfully demonstrate the effectiveness and practicality of the proposed method.

Comparison of Adaptive and Robust Controllers for Fully-Constrained and Redundant Planar Cable Robots

2014 ◽  
Author(s):  
Sergio J. Torres-Mendez ◽  
Gokhan Gungor ◽  
Baris Fidan ◽  
Amir Khajepour
Keyword(s):  
Pid Controller ◽  
Position Control ◽  
Sliding Mode ◽  
Uncertain Parameters ◽  
Input Output ◽  
Adaptive Controllers ◽  
Control Scheme ◽  
Control Schemes ◽  
Novel Method ◽  
Simulation Results

This work deals with the design and comparison of two adaptive position control schemes with a classical PID controller for fully constrained and redundant planar robots. First, a novel method based on inclusion of virtual cables facilitates the linear separation of the uncertain parameters from the input-output signals. Then, two Lyapunov based adaptive controllers based on the sliding mode and PD schemes are designed to compensate for the structure matrix uncertainties, which result from errors in the anchor point locations. Finally, the adaptive controllers are evaluated and compared with a classical PID controller through simulations for a desired 2D singularity-free pose of the mobile platform. The simulation results have shown that the adaptive PD control scheme has the best performance for both fully constrained and redundant cases.

Stick-Slip Effect in a Vibration-Driven System With Dry Friction: Sliding Bifurcations and Optimization

2013 ◽  
Vol 81 (5) ◽  
Author(s):  
Hongbin Fang ◽  
Jian Xu
Keyword(s):  
Steady State ◽  
Bifurcation Diagram ◽  
Dry Friction ◽  
Classical Mechanics ◽  
System Optimization ◽  
Physical Parameters ◽  
Stick Slip ◽  
Friction Forces ◽  
Driven System ◽  
Different Types

Vibration-driven systems can move progressively in resistive media owing to periodic motions of internal masses. In consideration of the external dry friction forces, the system is piecewise smooth and has been shown to exhibit different types of stick-slip motions. In this paper, a vibration-driven system with Coulomb dry friction is investigated in terms of sliding bifurcation. A two-parameter bifurcation problem is theoretically analyzed and the corresponding bifurcation diagram is presented, where branches of the bifurcation are derived in view of classical mechanics. The results show that these sliding bifurcations organize different types of transitions between slip and sticking motions in this system. The bifurcation diagram and the predicted stick-slip transitions are verified through numerical simulations. Considering the effects of physical parameters on average steady-state velocity and utilizing the sticking feature of the system, optimization of the system is performed. Better performance of the system with no backward motion and higher average steady-state velocity can be achieved, based on the proposed optimization procedures.

scholarly journals Decentralized Control for Scalable Quadcopter Formations

2016 ◽  
Vol 2016 ◽  
pp. 1-10
Author(s):  
Qasim Ali ◽  
Sergio Montenegro
Keyword(s):  
Position Control ◽  
Linear Quadratic Regulator ◽  
Linear Quadratic ◽  
Time Duration ◽  
Control Effort ◽  
Ground Station ◽  
Model Following ◽  
Control Scheme ◽  
Control Schemes ◽  
And Control

An innovative framework has been developed for teamwork of two quadcopter formations, each having its specified formation geometry, assigned task, and matching control scheme. Position control for quadcopters in one of the formations has been implemented through a Linear Quadratic Regulator Proportional Integral (LQR PI) control scheme based on explicit model following scheme. Quadcopters in the other formation are controlled through LQR PI servomechanism control scheme. These two control schemes are compared in terms of their performance and control effort. Both formations are commanded by respective ground stations through virtual leaders. Quadcopters in formations are able to track desired trajectories as well as hovering at desired points for selected time duration. In case of communication loss between ground station and any of the quadcopters, the neighboring quadcopter provides the command data, received from the ground station, to the affected unit. Proposed control schemes have been validated through extensive simulations using MATLAB®/Simulink® that provided favorable results.

Simulation of Closed Loop Electro-Hydraulic Actuator Using PID Based on AMESim

2015 ◽  
Vol 789-790 ◽  
pp. 865-872
Author(s):  
Mehmood Qaiser
Keyword(s):  
Physical Model ◽  
Motion Control ◽  
Hydraulic System ◽  
Position Control ◽  
Hydraulic Systems ◽  
Hydraulic Actuator ◽  
Simple Task ◽  
Hydraulic Actuators ◽  
Identification Technique ◽  
Control Application

Electro-hydraulic actuators are widely used in motion control application. Position control using hydraulic systems is widely applied in several engineering fields. However, their design is not a simple task since it is necessary to observe their behavior according to control theory.This paper represents an implementation of motion control of electro-hydraulic actuator by using PID controller. The objective of this study was to obtain Physical model of an electro-hydraulic actuator using system identification technique by estimating model using AMESim and provide the electro-hydraulic system which depends the hydraulic actuators to meet the motion control system demands.The physical model of electro-hydraulic actuator is established; it was modeled and simulated by using advanced performance modeling and simulation environment AMESim. It is shown that using AMESim to model and simulate performance more directly and veritably, and can complete the design task accurately and quickly.

scholarly journals Nonlinear Current-Mode Control of SCIG Wind Turbines

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 55
Author(s):  
Nicholas Hawkins ◽  
Bhagyashri Bhagwat ◽  
Michael L. McIntyre
Keyword(s):  
Current Mode ◽  
Nonlinear Controller ◽  
Flux Observer ◽  
Current Mode Control ◽  
Mode Control ◽  
Squirrel Cage ◽  
Control Scheme ◽  
Control Schemes ◽  
Rotor Flux ◽  
Squirrel Cage Induction Generator

In this paper, a nonlinear controller is proposed to manage the rotational speed of a full-variable Squirrel Cage Induction Generator wind turbine. This control scheme improves upon tractional vector controllers by removing the need for a rotor flux observer. Additionally, the proposed controller manages the performance through turbulent wind conditions by accounting for unmeasurable wind torque dynamics. This model-based approach utilizes a current-based control in place of traditional voltage-mode control and is validated using a Lyapunov-based stability analysis. The proposed scheme is compared to a linear vector controller through simulation results. These results demonstrate that the proposed controller is far more robust to wind turbulence than traditional control schemes.

scholarly journals Constant Transmission Efficiency Dimming Control Scheme for VLC Systems

Photonics ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 7
Author(s):  
Jia-Ning Guo ◽  
Jian Zhang ◽  
Gang Xin ◽  
Lin Li
Keyword(s):  
Visible Light Communication ◽  
Transmission Efficiency ◽  
Error Performance ◽  
Constant Weight ◽  
Block Coding ◽  
Control Scheme ◽  
Control Schemes ◽  
Indoor Wireless ◽  
Communication Function ◽  
Dimming Control

As a novel mode of indoor wireless communication, visible light communication (VLC) should consider the illumination functions besides the primary communication function. Dimming control is one of the most crucial illumination functions for VLC systems. However, the transmission efficiency of most proposed dimming control schemes changes as the dimming factor changes. A block coding-based dimming control scheme has been proposed for constant transmission efficiency VLC systems, but there is still room for improvement in dimming range and error performance. In this paper, we propose a dimming control scheme based on extensional constant weight codeword sets to achieve constant transmission efficiency. Meanwhile, we also provide a low implementation complexity decoding algorithm for the scheme. Finally, comparisons show that the proposed scheme can provide a wider dimming range and better error performance.

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