On stability for learning human control strategy by demonstrations using SVM

2019 ◽  
Vol 40 (1) ◽  
pp. 118-131
Author(s):  
Zhiyang Wang ◽  
Yongsheng Ou
Keyword(s):  
Control Strategy ◽  
Stability Region ◽  
Balance Control ◽  
Domain Of Attraction ◽  
Lyapunov Theory ◽  
Support Vector ◽  
Discrete Time System ◽  
Content Type ◽  
Human Control ◽  
The Stability

Purpose This paper aims to deal with the trade-off of the stability and the accuracy in learning human control strategy from demonstrations. With the stability conditions and the estimated stability region, this paper aims to conveniently get rid of the unstable controller or controller with relatively small stability region. With this evaluation, the learning human strategy controller becomes much more robust to perturbations. Design/methodology/approach In this paper, the criterion to verify the stability and a method to estimate the domain of attraction are provided for the learning controllers trained with support vector machines (SVMs). Conditions are formulated based on the discrete-time system Lyapunov theory to ensure that a closed-form of the learning control system is strongly stable under perturbations (SSUP). Then a Chebychev point based approach is proposed to estimate its domain of attraction. Findings Some of such learning controllers have been implemented in the vertical balance control of a dynamically stable, statically unstable wheel mobile robot.

Constant force control for aluminum wheel hub grinding based on ESO + backstepping

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shijie Dai ◽  
Yufeng Zhao ◽  
Wenbin Ji ◽  
Jiaheng Mu ◽  
Fengbao Hu
Keyword(s):  
Control Strategy ◽  
Force Control ◽  
Control Method ◽  
Response Speed ◽  
Backstepping Control ◽  
Constant Force ◽  
Content Type ◽  
Disturbance Rejection Control ◽  
The Stability ◽  
Differential Control

Purpose This paper aims to present a control method to realize the constant force grinding of automobile wheel hub. Design/methodology/approach A constant force control strategy combined by extended state observer (ESO) and backstepping control is proposed. ESO is used to estimate the total disturbance to improve the anti-interference and stability of the system and Backstepping control is used to improve the response speed of the system. Findings The simulation and grinding experimental results show that, compared with the proportional integral differential control and active disturbance rejection control, the designed controller can improve the dynamic response performance and anti-interference ability of the system and can quickly track the expected force and improve the grinding quality of the hub surface. Originality/value The main contribution of this paper lies in the proposed of a new constant force control strategy, which significantly improved the stability and precision of grinding force.

scholarly journals New time delay estimation-based virtual decomposition control for n-DoF robot manipulator

2021 ◽  
Vol 10 (3) ◽  
pp. 192
Author(s):  
Hachmia Faqihi ◽  
Khalid Benjelloun ◽  
Maarouf Saad ◽  
Mohammed Benbrahim ◽  
M. Nabil Kabbaj
Keyword(s):  
Time Delay ◽  
Dynamic Model ◽  
Control Strategy ◽  
Robot Manipulator ◽  
Time Delay Estimation ◽  
Lyapunov Theory ◽  
Degree Of Freedom ◽  
Delay Estimation ◽  
The Stability

<p>One of the most efficient approaches to control a multiple degree-of-freedom robot manipulator is the virtual decomposition control (VDC). However, the use of the re- gressor technique in the conventionnal VDC to estimate the unknown and uncertaities parameters present some limitations. In this paper, a new control strategy of n-DoF robot manipulator, refering to reorganizing the equation of the VDC using the time delay estimation (TDE) have been investigated. In the proposed controller, the VDC equations are rearranged using the TDE for unknown dynamic estimations. Hence, the decoupling dynamic model for the manipulator is established. The stability of the overall system is proved based on Lyapunov theory. The effectiveness of the proposed controller is proved via case study performed on 7-DoF robot manipulator and com- pared to the conventionnal Regressor-based VDC according to some evalution criteria. The results carry out the validity and efficiency of the proposed time delay estimation- based virtual decomposition controller (TD-VDC) approach.</p>

Contact-Dependent Balance Stability of Walking Robots

2017 ◽  
Author(s):  
Carlotta Mummolo ◽  
William Z. Peng ◽  
Carlos Gonzalez ◽  
Joo H. Kim
Keyword(s):  
Stability Region ◽  
Balance Control ◽  
Center Of Mass ◽  
Biped Robot ◽  
Walking Robots ◽  
Ground Contact ◽  
Robotic Platform ◽  
Contact Configuration ◽  
The Stability ◽  
Balance Stability

A novel theoretical framework for the identification of the balance stability regions of biped systems is implemented on a real robotic platform. With the proposed method, the balance stability capabilities of a biped robot are quantified by a balance stability region in the state space of center of mass (COM) position and velocity. The boundary of such a stability region provides a threshold between balanced and falling states for the robot by including all possible COM states that are balanced with respect to a specified feet/ground contact configuration. A COM state outside of the stability region boundary is the sufficient condition for a falling state, from which a change in the specified contact configuration is inevitable. By specifying various positions of the robot’s feet on the ground, the effects of different contact configurations on the robot’s balance stability capabilities are investigated. Experimental walking trajectories of the robot are analyzed in relationship with their respective stability boundaries, to study the robot balance control during various gait phases.

Backstepping Control for a Five-Phase Permanent Magnet Synchronous Motor Drive

2015 ◽  
Vol 6 (4) ◽  
pp. 842 ◽  
Author(s):  
Anissa Hosseynia ◽  
Ramzi Trabelsi ◽  
Atif Iqbal ◽  
Med Faouzi Mimounia
Keyword(s):  
Permanent Magnet ◽  
Control Strategy ◽  
Permanent Magnet Synchronous Motor ◽  
Synchronous Motor ◽  
Backstepping Control ◽  
Lyapunov Theory ◽  
Motor Drive ◽  
Control Law ◽  
Backstepping Controller ◽  
The Stability

This paper deals with the synthesis of a speed control strategy for a five-phase permanent magnet synchronous motor (PMSM) drive based on backstepping controller. The proposed control strategy considers the nonlinearities of the system in the control law. The stability of the backstepping control strategy is proved by the Lyapunov theory. Simulated results are provided to verify the feasibility of the backstepping control strategy.

Fixed-time compliant motion/force control of robotic manipulators with environmental constraints

2017 ◽  
Vol 37 (3) ◽  
pp. 271-277 ◽  
Author(s):  
Chao Ma
Keyword(s):  
Control Strategy ◽  
Force Control ◽  
Stability Theory ◽  
Robotic Manipulators ◽  
Fixed Time ◽  
Lyapunov Theory ◽  
Environmental Constraints ◽  
Time Stability ◽  
Content Type ◽  
Compliant Motion

Purpose The purpose of this paper is to design a new compliant motion/force control strategy for robotic manipulators with environmental constraints in the sense of fixed-time stability. Design/methodology/approach This paper investigates a novel compliant motion/force control strategy for robotic manipulators with environmental constraints. By using the Lyapunov theory and fixed-time stability theory, a non-singular terminal sliding mode manifold is first established. Then, the compliant motion/force controller is designed, and relevant conditions are given for guaranteeing that the robotic manipulator can track the prescribed constrained trajectory while exerting a desired force to the environment in fixed-time. An illustrative example is presented to show the effectiveness of our proposed control strategy. Findings Based on fixed-time stability theory, the desired compliant motion/force controller for robotic manipulators with environmental constraints is developed. Originality/value Compared with most existing literature, the proposed fixed-time compliant motion/force control strategy can provide the upper bound of the settling time independent of the initial conditions in designing procedure and is more practical for the real-world applications.

Control of an Underactuated Three-Link Passive–Active–Active Manipulator Based on Three Stages and Stability Analysis

2014 ◽  
Vol 137 (2) ◽  
Author(s):  
Xu-Zhi Lai ◽  
Chang-Zhong Pan ◽  
Min Wu ◽  
Simon X. Yang ◽  
Wei-Hua Cao
Keyword(s):  
Nonlinear Control ◽  
Control Strategy ◽  
Lyapunov Theory ◽  
Control Law ◽  
Integrated Method ◽  
The Third ◽  
Preparatory Stage ◽  
The Stability ◽  
And Control ◽  
Nonlinear Control Law

This paper presents a novel three-stage control strategy for the motion control of an underactuated three-link passive–active–active (PAA) manipulator. First, a nonlinear control law is designed to make the angle and angular velocity of the third link convergent to zero. Then, a swing-up control law is designed to increase the system energy and control the posture of the second link. Finally, an integrated method with linear control and nonlinear control is introduced to stabilize the manipulator at the straight-up position. The stability of the control system is guaranteed by Lyapunov theory and LaSalle’s invariance principle. Compared to other approaches, the proposed strategy innovatively introduces a preparatory stage to drive the third link to stretch-out toward the second link in a natural way, which makes the swing-up control easy and quick. Besides, the intergraded method ensures the manipulator moving into the balancing stage smoothly and easily. The effectiveness and efficiency of the control strategy are demonstrated by numerical simulations.

Inducing sustained oscillations in a class of nonlinear discrete time systems

2016 ◽  
Vol 24 (6) ◽  
pp. 1162-1170 ◽  
Author(s):  
AR Hakimi ◽  
T Binazadeh
Keyword(s):  
Limit Cycle ◽  
Discrete Time ◽  
Stable Limit Cycle ◽  
Domain Of Attraction ◽  
Stable Limit ◽  
Discrete Time System ◽  
Sustained Oscillations ◽  
Discrete Time Systems ◽  
The Stability ◽  
Time Systems

Inducing sustained oscillations in a class of nonlinear discrete time systems is studied in this paper. The novelty of this paper is based on the proposed approach in generating stable oscillations according to limit cycle control. The limit cycle control is not formulated for nonlinear discrete time systems of any order and this paper concentrates on this issue. Considering the stable limit cycle as a positive limit set for the dynamical system, a nonlinear control law is designed to create the considered limit cycle in the phase trajectories of the closed-loop nonlinear discrete time system to achieve oscillations with the desirable amplitude and frequency. For this purpose, firstly, the limit cycle control is proposed for second-order nonlinear discrete time systems. The stability analysis of the generated limit cycle is done via a suitable Lyapunov function. Also, the domain of attraction of the created limit cycle is calculated. The proposed method is then extended for nonlinear discrete time systems of any order via the backstepping technique. Finally, computer simulations are performed for a practical example to demonstrate the ability of the designed controller in generating stable oscillations.

scholarly journals A Secure Control Design for Networked Control Systems with Linear Dynamics under a Time-Delay Switch Attack

Electronics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 322
Author(s):  
Mauro Victorio ◽  
Arman Sargolzaei ◽  
Mohammad Reza Khalghani
Keyword(s):  
Time Delay ◽  
Control Systems ◽  
Real Time ◽  
Control Strategy ◽  
Large Scale ◽  
Networked Control Systems ◽  
Lyapunov Theory ◽  
Networked Control ◽  
Secure Control ◽  
The Stability

Networked control systems (NCSs) are designed to control and monitor large-scale and complex systems remotely. The communication connectivity in an NCS allows agents to quickly communicate with each other to respond to abrupt changes in the system quickly, thus reducing complexity and increasing efficiency. Despite all these advantages, NCSs are vulnerable to cyberattacks. Injecting cyberattacks, such as a time-delay switch (TDS) attack, into communication channels has the potential to make NCSs inefficient or even unstable. This paper presents a Lyapunov-based approach to detecting and estimating TDS attacks in real time. A secure control strategy is designed to mitigate the effects of TDS attacks in real time. The stability of the secure control system is investigated using the Lyapunov theory. The proposed TDS attack estimator’s performance and secure control strategy are evaluated in simulations and a hardware-in-the-loop environment.

Global Robust Terminal Sliding Mode Control for PMLSM Servo System

2013 ◽  
Vol 273 ◽  
pp. 280-285 ◽  
Author(s):  
Hong Pei Han ◽  
Wu Wang ◽  
Zheng Min Bai
Keyword(s):  
Sliding Mode Control ◽  
Control Strategy ◽  
External Load ◽  
Sliding Mode ◽  
Servo System ◽  
Lyapunov Theory ◽  
Terminal Sliding Mode Control ◽  
Terminal Sliding Mode ◽  
Mode Control ◽  
The Stability

Permanent Magnet Linear Synchronous Motor (P MLSM was hard to control with traditional control strategy for parameters variation and external load disturbance, a global robust terminal sliding mode control (GRTSMC) was designed for PMLSM servo system, the sliding mode surface function was designed, the robust sliding mode control law was deduced and the stability was proved by Lyapunov theory. With the mathematical models of PMLSM, the simulation was taken with traditional PID control, SMC control and GRTSMC control proposed in this paper, the robust performance be found with GRTSMC control when motor parameters and external load changed, the efficiency and advantages of this robust control strategy was successfully demonstrated.

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