Nonlinear Force/Pressure Tracking of an Electro-Hydraulic Actuator1

1998 ◽  
Vol 122 (1) ◽  
pp. 232-236 ◽  
Author(s):  
Rui Liu ◽  
Andrew Alleyne
Keyword(s):  
Control Algorithm ◽  
Experimental System ◽  
Hydraulic Actuator ◽  
Parameter Uncertainties ◽  
Friction Modeling ◽  
Parameter Adaptation ◽  
Standard Parameter ◽  
Nonlinear Force ◽  
Adaptation Scheme ◽  
Force Pressure

In this paper, a Lyapunov-based control algorithm is developed for the force/pressure tracking control of an electro-hydraulic actuator. The controller relies on an accurate model of the system. To compensate for the parameter uncertainties, a standard parameter adaptation based on Lyapunov analysis is applied. The control law is coupled with the adaptation scheme and applied to an experimental system. Friction modeling and compensation for pressure tracking are discussed and experimental results shown. The results show that the nonlinear control algorithm together with the adaptation scheme gives a good performance for the specified task. [S0022-0434(00)00501-3]

scholarly journals Sliding Mode Robot Control with Friction and Payload Estimation

2004 ◽  
Vol 8 (5) ◽  
pp. 553-561 ◽  
Author(s):  
Lörinc Márton ◽  
◽  
Béla Lantos ◽  
Keyword(s):  
Robot Control ◽  
Control Algorithm ◽  
Lyapunov Method ◽  
Sliding Mode ◽  
Robot Arm ◽  
Tracking Accuracy ◽  
Parameter Adaptation ◽  
Robust Parameter ◽  
Payload Mass ◽  
Friction Parameters

The paper deals with robust motion control of robotic systems with unknown friction parameters and payload mass. The parameters of the robot arm were considered known with a given precision. To solve the control of the robot with unknown payload mass and friction parameters, sliding mode control algorithm was proposed combined with robust parameter adaptation techniques. Using Lyapunov method it was shown that the resulting controller achieves a guaranteed final tracking accuracy. Simulation results are presented to illustrate the effectiveness and achievable control performance of the proposed scheme.

scholarly journals Robust H ∞ state-feedback control for linear systems

2017 ◽  
Vol 473 (2200) ◽  
pp. 20160934 ◽  
Author(s):  
Hao Chen ◽  
Zhenzhen Zhang ◽  
Huazhang Wang
Keyword(s):  
Feedback Control ◽  
Linear Systems ◽  
Control Algorithm ◽  
State Feedback ◽  
Convex Combination ◽  
State Feedback Control ◽  
Parameter Uncertainties ◽  
Globally Asymptotically Stable ◽  
Loop Control ◽  
Control Approach

This paper investigates the problem of robust H ∞ control for linear systems. First, the state-feedback closed-loop control algorithm is designed. Second, by employing the geometric progression theory, a modified augmented Lyapunov–Krasovskii functional (LKF) with the geometric integral interval is established. Then, parameter uncertainties and the derivative of the delay are flexibly described by introducing the convex combination skill. This technique can eliminate the unnecessary enlargement of the LKF derivative estimation, which gives less conservatism. In addition, the designed controller can ensure that the linear systems are globally asymptotically stable with a guaranteed H ∞ performance in the presence of a disturbance input and parameter uncertainties. A liquid monopropellant rocket motor with a pressure feeding system is evaluated in a simulation example. It shows that this proposed state-feedback control approach achieves the expected results for linear systems in the sense of the prescribed H ∞ performance.

Adaptive altitude flight control of quadcopter under ground effect and time-varying load: theory and experiments

2021 ◽  
pp. 107754632110501
Author(s):  
Ji-Won Lee ◽  
Nguyen Xuan-Mung ◽  
Ngoc Phi Nguyen ◽  
Sung Kyung Hong
Keyword(s):  
Flight Control ◽  
Control Algorithm ◽  
Sliding Mode ◽  
Ground Effect ◽  
Lyapunov Theory ◽  
Control Technique ◽  
Time Varying ◽  
Control Performance ◽  
Parameter Uncertainties ◽  
Altitude Control

In recent years, the boom of the quadcopter industry resulted in a broad range of real-world applications which highlighted the urgent need to improve quadcopter control quality. Typically, external disturbances, such as wind, parameter uncertainties caused by payload variations, or the ground effect, can severely degrade the quadcopter’s altitude control performance. Meanwhile, widely used controllers like the proportional-integral-derivative control cannot guarantee control performance when the system is critically affected by factors that exhibit a high degree of variability with time. In this paper, an adaptive control algorithm is proposed to improve quadcopter altitude tracking performance in the presence of both the ground effect and a time-varying payload. First, we derive an adaptive altitude control algorithm using the sliding mode control technique to account for these uncertainties in the quadcopter dynamics model. Second, we apply Lyapunov theory to analyze the stability of the closed-loop system. Finally, we conduct several numerical simulations and experiments to validate the effectiveness of the proposed method.

scholarly journals Containment Control of Underactuated Ships with Environment Disturbances and Parameter Uncertainties

2017 ◽  
Vol 2017 ◽  
pp. 1-19 ◽  
Author(s):  
Qidan Zhu ◽  
Junda Ma ◽  
Zhilin Liu ◽  
Ke Liu
Keyword(s):  
Control Algorithm ◽  
Sliding Mode ◽  
Parameter Uncertainties ◽  
Feedback Form ◽  
Tracking Errors ◽  
External Disturbances ◽  
Simulation Experiments ◽  
Containment Control ◽  
State Information ◽  
Control Objective

An implementable robust containment control algorithm is proposed for a group of underactuated ships in the presence of hydrodynamic parameter uncertainties and external disturbances. The control objective is to drive all the followers into the convex hull spanned by the virtual leaders, whose state information is available only to a subset of the followers. For this purpose, the ship model is primarily transformed to a strict-feedback form. In the kinematic design, a virtual containment controller, requiring the state information from its neighbors, is presented based on the results obtained from graph theory. In the dynamic design, a robust containment controller is developed through utilizing upper-to-up sliding mode control. In addition, in order to simplify the implementations of the control law, the command filtered backstepping (CFBP) method is introduced to prevent the analytic differentiations of the virtual law from each design step of the backstepping (BP) method. Subsequently, it is well proven that all the tracking errors could converge to and remain small neighborhoods of the equilibrium point. Finally, several simulation experiments are conducted to demonstrate the performance of the proposed control algorithm.

Simulation and Experiment Study of Hybrid Actuators Five-Bar Mechanism Kinematics Parameter

2010 ◽  
Vol 148-149 ◽  
pp. 168-171
Author(s):  
Ning Shan
Keyword(s):  
Pid Control ◽  
Control Algorithm ◽  
Closed Loop ◽  
Control Method ◽  
Experimental System ◽  
Experiment Study ◽  
The Real ◽  
Input Parameters ◽  
Simulation And Experiment ◽  
Kinematics Parameters

The kinematics model of planar closed-loop five-bar mechanism is established in this paper. The influence of mechanism’s input parameters on the output kinematics parameters is investigated by simulation. The five-bar mechanism is designed. The experimental system of hybrid actuators five-bar mechanism is established based PID control method. The experiment investigates the influence of mechanism’s input parameters on the output kinematics parameters. The results show that the mechanism’s output kinematics parameters depend on input parameters. The original angle of input bar is bigger, curves of kinematics parameters of output bar change more acutely. Applying PID control algorithm to control the hybrid actuators linkage, the real kinematics parameters of linkage are almost consistent with theory values and the error is less.

Nonlinear adaptive position tracking of an electro-hydraulic actuator

2015 ◽  
Vol 229 (17) ◽  
pp. 3252-3265 ◽  
Author(s):  
Kai Guo ◽  
Jianhua Wei ◽  
Qiyan Tian
Keyword(s):  
Disturbance Observer ◽  
Lyapunov Theory ◽  
Observer Design ◽  
Estimation Accuracy ◽  
Load Force ◽  
Position Tracking ◽  
Hydraulic Actuator ◽  
Parameter Uncertainties ◽  
External Disturbances ◽  
Tracking Controller

This paper deals with position tracking control of a single-rod electro-hydraulic actuator subject to external disturbances and parameter uncertainties. In previous disturbance observer design methodologies for electro-hydraulic actuators, parameter uncertainties have been commonly regarded as disturbances and lumped together with external perturbations. However, in practical electro-hydraulic systems, system parameters are unknown and varying. If considerable parameter uncertainties exist in the system or if the disturbance dynamics induced by parameter uncertainties exceed the bandwidth of the disturbance observer, estimation accuracy will degrade, which will significantly affect system performance. To solve this problem, an extended disturbance observer is proposed in this paper to estimate disturbances while dealing with parameter uncertainties. In addition, a nonlinear position tracking controller is designed for position tracking based on the proposed disturbance observer using a backstepping technique. The proof of the stability of the overall closed-loop system is based on Lyapunov theory. The performance of the proposed controller is verified through simulations and experiments using a shock absorber as a load force generator. A detailed nonlinear physical model of the load force is developed and implemented in the simulation. The results show that the proposed nonlinear position tracking controller, together with the extended disturbance observer, provide excellent tracking performance in the presence of parameter uncertainties and external disturbances.

Linear robust trajectory control of flexible joint manipulators

Robotica ◽  
1996 ◽  
Vol 14 (4) ◽  
pp. 375-380 ◽  
Author(s):  
Yueh-Jaw Lin ◽  
Aiping Yu
Keyword(s):  
Control Algorithm ◽  
Control Law ◽  
Parameter Uncertainties ◽  
Velocity Feedback ◽  
Flexible Joint ◽  
Flexible Joint Robots ◽  
Control Schemes ◽  
On Line ◽  
General Meaning ◽  
Point To Point

SUMMARYThis paper presents a practical approach for the point-to-point control of elastic-jointed robot manipulators. With the proposed approach only position and velocity feedback are referenced, as opposed to most of the existing control schemes of elastic-jointed manipulators which require additional acceleration and/or jerk feedback. To guarantee the robustness of the controller, it is designed on extreme parameter uncertainties due to highly elastic joints of manipulators and energy motivated Lyapunov functions are used to derive the control law. Four pertinent controller gains are chosen in light of the on-line position and velocity feedback of the links and joint sensors. Through a simulated experimental verification, it is demonstrated that the designed simple position and velocity feedback controller, similar to that used for rigid-jointed robots, can globally stabilize the elastic-jointed robot for a bounded reference position. In addition, the tracking performance of the controller reveals that this simple control algorithm is robust in terms of joint flexibility. And the simplicity of the presented control algorithm, as compared to other model-based techniques for flexiblejoint robots, is particularly advantageous. Even though the simulated experiments are conducted on a single-link flexible joint robot, control law derived in this paper has general meaning for multi-link flexible joint robots.

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