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In this paper, adaptive neural network control is proposed for a robotic exoskeleton that contains unknown parameters in its dynamic. Neural networks are used to compensate for the unknown deadzone effect caused by the actuators and the unknown dynamics of the robot. State-feedback control is proposed and a disturbance observer is then designed to estimate the unknown disturbance. Radial Basis Function...
This paper studies car trajectory predictions desired in several active safety systems, such as automatic emergency braking (AEB) systems and lane keeping systems (LKS). In the former, the car trajectory is estimated such that objects detected within this trajectory in front of current host vehicle are taken into consideration of collision avoidance. In LKS, the trajectory predictor is utilized to...
In this paper, we present a non-centralized approach to the output-feedback variant of tube-based model predictive control of dynamically coupled linear time-invariant systems with shared constraints. The proposed algorithm achieves guaranteed recursive feasibility and closed-loop asymptotic stability of the overall system. The approach combines decentralized and distributed MPC, hence the name quasi-distributed...
The magnetic levitation (MagLev) system control is one of the most complex problems due to open-loop instability, nonlinear dynamics and uncertain parameters. The 3rd order differential model of MagLev is linearized by using input-output linearization. The control law is designed using feedback linearization (FL) augmented by uncertainty estimates. The states and uncertainties are estimated using...
The problem of reduced-order observer-based finite-time stabilization for Lur'e-type differential inclusion systems is investigated. Based on the concept of finite-time stability in [1,2], a reduced-order observer-based finite-time controller is proposed to make the trajectory of the closed-loop system stay within a prescribed bound in a fixed time interval. Such sufficient conditions are obtained...
This paper presents a perfect tracking method by combining iterative learning control (ILC) with disturbance observer (DOB) for CNC machine tools that perform the same tasks repeatedly. Although CNC systems have many nonlinear factors, they can be easily solved by ILC instead of complicated modeling. Also, for repeated disturbance, ILC performs very well and for non-repeated disturbance, DOB works...
This paper presents a novel BOTMA based upon two types of bearing measurements: the angles of arrival of electromagnetic waves and the angles of arrival of acoustic waves. The difference of the propagation delays makes the problem observable even when the observer is motionless or non-maneuvering. We construct a recursive estimator (using the extended Kalman filter) and a batch estimator (the maximum...
In this paper, an optimal preview controller for the Nao biped robot is developed based on a three-dimensional linear inverted pendulum model and zero moment point stability criterion. In order to estimate the unmeasurable state vector, an unscented Kalman filter state observer is proposed which guarantees robustness of the control loop through loop transfer recovery and provides asymptotic stability...
This paper considers the attitude stabilization problem for the rigid body that evolves on the Lie group with external unknown disturbances. The attitude kinematics of the rigid body are developed directly on the special orthogonal group SO(3), which can describe the rigid body's rotation uniquely and globally in comparison with the common parameterization method such as Euler angles and quaternion...
Based on the Observer/Kalman filter Identification (OKID) and digital redesign of observer-based tracker method for a stochastic chaotic system. An additional digital redesign observer approach is now proposed to obtain a more accurate system identification model. Furthermore, this provides computationally effective initialization low-order observer parameters for the on-line nonlinear model system...
This paper develops a solution to the cooperative output tracking problem of a network of non-minimum phase (NMP) vehicles under a direct and time-varying communication topology. The desired trajectory is generated by a linear exo-system and accessible to partial vehicles. The solution consists of three modules: a distributed observer network (DON), a causal stable inversion (CSI), and a state trajectory...
An Active Disturbance Rejection Control based on Generalized Proportional Integral observer (ADRC with GPI observer) was developed to control the gait of a bipedal robot with five degrees of freedom. The bipedal robot used is a passive point feet which produces an underactuated dynamic walking. A virtual holonomic constraint is imposed to generate online smooth trajectories which were used as references...
The phenomenon of using control actions to communicate is called signaling. Signaling is often beneficial in decentralized control problems with imperfect communication between agents. Seemingly simple control problems with signaling are often mathematically challenging. Humans, however, lack high-speed communication channels and routinely employ signaling strategies during cooperative movements....
In this paper, a method of unmatched disturbance compensating integral sliding model predictive control for constrained linear discrete-time systems with bounded disturbances is presented. The basic idea is to shape a discrete-time integral sliding mode control into an optimal constrained control problem with model predictive control. By choosing another projection matrix in the integral sliding surface,...
The conventional application of the active disturbance rejection control (ADRC) scheme leads to robust feedback-linearization of the original system dynamics which is followed next by a design of the outer-loop state-feedback with feedforward controller designed for the resultant chain of integrators. The latter design stage assumes perfect knowledge (availability) of the consecutive reference time-derivatives...
This paper investigates the proglem of robust quantized sliding mode control for continuous-time Markovian jump systems. A filtering-based technique is proposed to render strictly continuous signals from piecewise quantized signals, based on which a sliding mode observer scheme is developed to obtain the asymptotic estimation of system state. Then, an observer-based control scheme is proposed to stabilize...
The road curvature is an important characteristic, specially for systems tracking a target trajectory. However, in some cases, this value is not available and its dynamics is unknown and has to be estimated to be used by control. By considering vehicle lateral dynamics, the steering system and the Radar/Camera information, the standard Traffic Jam Pilot (TJP) system is presented. Current TJP solutions...
A combination of model predictive control with output integral sliding mode techniques is proposed. The output integral sliding mode controller protects the nominal control provided by the predictive controller against matched perturbations. The entire concept exploits output information only. The control strategy is tested in the laboratory on a mass positioning system.
This paper is concerned with the design and implementation of a position adaptive nonlinear zero-dynamic tracking controller (ANZTC) for a three phase squirrel-cage induction motor (IM). This controller is designed for a fifth-order model of an induction motor which includes both electrical and mechanical dynamics under the assumptions of linear magnet circuits, written in d-q coordinates. A linear...
A two-time-scale guidance law is proposed for soft landing on asteroids to recover the desired descent trajectory in the presence of uncertainties due to inaccurate model of the asteroid's gravitational field as well as solar gravity and radiation pressure. A high-gain observer estimates the uncertainties over the faster time scale and a nonlinear controller uses these estimates to cancel the effect...
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