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Ball and Plate system is a well-known benchmark to test control strategies because of its multivariable nonlinear coupled dynamics, open loop instability and under actuation. Moreover, presence of parameter uncertainty and external disturbance makes it further challenging and interesting. This calls for a robust controller which not only stabilises the ball on the plate but also makes the ball follow...
An adaptive iterative learning control (AILC) is proposed to release the requirement of repetitiveness for a class of multiple-input multiple-output nonlinear systems. Based on high-order internal model, the time-iteration-varying law of parametric uncertainty is expressed. Furthermore, reference trajectory and initial state are varying from iteration to iteration randomly. The asymptotic convergence...
This paper researches the tracking-control problem of multiple-integrator (MI) systems via Zhang dynamics (ZD), which is a powerful class of dynamics to solve online time-varying problems. Based on design procedures of the so-called ZD controllers for five low-order integrator systems, the general formula of the ZD controller for the nth-order integrator system is elaborately given, and theoretical...
In spot-scanning particle therapy, inverse treatment planning is usually limited to finding the optimal beam fluences given the beam trajectories and energies. We address the much more challenging problem of jointly optimizing the beam fluences, trajectories and energies. For this purpose, we design a simulated annealing algorithm with an exploration mechanism that balances the conflicting demands...
This paper aims at achieving the stabilization control of hyper-chaotic Lu system with only one control input. By employing Zhang dynamics (ZD) method, which is a simple and effective method for designing control input, the expression of the desired controller is thus obtained. This easy-to-design controller, synthesized by following specific steps of ZD design method, is able to stabilize the 4th-order...
This paper proposes an effective method to balance the confliction between higher steady-state precision and stronger robustness in sliding-mode control systems. Different from the conventional two-phase-based sliding-mode control, the proposed sliding-mode control (SMC) is divided into a three-phase-based control, which include the first reaching phase, the second sliding-mode moving phase and the...
In this paper, we solve the leader-following consensus problem using nearly cyclic pursuit (NCP) and a two-layer hierarchical nearly cyclic pursuit (HNCP). First, we design a control strategy based on the nearly cyclic pursuit(NCP) to enable the agents to rendezvous at a point. Second, we propose a two-layer HNCP for a leader-following consensus problem to increase the convergence rate of the network...
A nonlinear adaptive path following controller for a kite based airborne wind energy system is presented. For a given desired geometric path, we provide necessary conditions for closed-loop convergence of the kite to a tube centered around the desired path. The proposed controller is adapts for the case of unknown wind vector and kite parameters. The effectiveness of the approach is demonstrated via...
Implementing state-based parameterized periodic trajectories on complex robotic systems, e.g., humanoid robots, can lead to instability due to sensor noise exacerbated by dynamic movements. As a means of understanding this phenomenon, and motivated by field testing on the humanoid robot DURUS, this paper presents sufficient conditions for the boundedness of hybrid periodic orbits (i.e., boundedness...
In this work, we address the inverse kinematics problem for parallel mechanisms using a differential kinematics approach based on the recently proposed Filtered Inverse method. The key idea behind the method is to employ an inversion algorithm which dynamically estimates the inverse of the Jacobian matrix, rather than using the instantaneous calculation of the true inverse. An interesting property...
This paper studies the issue of input saturation in tracking control of differential drive robots. Although the structure of control strategy is a determinant factor for the occurrence of saturation phenomena, having a trajectory for the robot that is compatible with the bounds on the inputs is a necessary condition for avoiding saturation. In this study, analytic conditions for determining the compatibility...
A novel control technique is proposed by combining P-type Iterative learning control (ILC) and model predictive control (MPC) with updating-reference for point-to-point tracking problem of batch process. In this paper, a batch-to-batch updating-reference, which passes through the desired points, is designed as the tracking trajectory within batch. The update law consists of two parts: P-type ILC and...
In this paper, an iterative method for synthesizing optimal controls for the bilinear quadratic tracking problem is investigated. The presented method is easy to implement as the control law of the bilinear system is obtained iteratively by considering a sequence of linear systems. The minimizing control law is calculated iteratively through solving a set of coupled state-dependent differential equations...
In this paper, an output regulation problem with unknown-input driven exosystem is formulated and solved for a class of nonlinear plant with unity relative degree. To handle both bounded and unbounded exosystems, we relaxed the asymptotic convergence requirement on the closed-loop state to its associated steady-state and proposed an approximated regulator-equation condition. By using changing supply...
This paper presents some further results on sliding mode control for a class of nonlinear systems with bounded uncertain parameters. A finite-time sliding manifold is proposed by incorporating piecewise defined function of time into the existing terminal sliding manifold, based on which a novel time-varying finite-time sliding mode controller is proposed. The proposed control strategy eliminates the...
In this paper, a global finite-time tracking control (GFTC) scheme is proposed for trajectory tracking control of an autonomous surface vehicle (ASV). The salient features of the GFTC scheme are triple fold: 1) A discontinuous controller is developed to realize the finite-time stability of the closed-loop ASV trajectory tracking system. 2) The GFTC scheme can render tracking errors converge to zero...
The aim of this paper is to present a simple and general control framework and convergent conditions applicable to nonholonomic systems, by using which one can control full generalized coordinates, including independent and dependent ones, and full constrained forces of the nonholonomic system to track their desired trajectory stably if the planned trajectory satisfies the proposed convergent conditions...
For the purpose of probe soft landing on small bodies safely, this paper focuses on improving convergence speed, decrease the chattering and process uncertainties and perturbations from the trajectory tracking control system. This paper presents improved Terminal sliding mode control based on active disturbance reject, which changes terminal sliding mode surface to the sliding mode hyper-surface and...
The paper designs an appropriate iterative learning control(ILC) algorithm based on the trajectory characteristics of lower extremity exoskeleton robot, and the algorithm utilizes variable forgetting factor not only does not affect the system in the convergence speed, but also it can enhance the robustness of the system. Considering the lower extremity exoskeleton robot trajectory is periodic motion,...
This paper deals with event-triggering based design of discrete-time sliding mode (DTSM) control for linear systems. Multirate output feedback based DTSM is designed with event-triggering strategy such that the system trajectories remain bounded in the vicinity of sliding manifold. An event-triggering rule is developed for DTSM which is evaluated only at periodic time intervals. The control is updated...
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