The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
An automated docking system is presented for an autonomous underwater vehicle utilizing light-field imaging for navigation guidance. This article focuses on three major components of the system: docking position acquisition with light-field imaging, optimal docking trajectory planning, and nonlinear trajectory tracking control. With the camera sensor data of each photographic exposure, depth maps...
This paper presents an approach to trajectory tracking control for autonomous vehicles subject to parametric uncertainties. Such uncertainties may have the potential to significantly decrease the performance of the system, even to the point of destabilizing it. Therefore, these parametric variations must be taken into account during the design of the controller. To solve the trajectory tracking problem...
This work aims to propose and compare trajectory tracking controllers for mobile robots. At first the mathematical requirements to propose a feasible strategy for a unicyclelike robot are presented, as well as the necessary condition to guarantee the stability in the sense of Lyapunov. In the sequence, the controllers are tuned in simulation and then validated in real experiments. The performance...
This paper presents the development and control of a novel active needle for percutaneous intervention. Using vision feedback of the actual tip of the needle, inverse kinematics based closed loop control in tracking a 3D curved path is performed. Shape Memory Alloy (SMA) wires are deployed as actuators for the developed active needle system. In-air experiments are performed to evaluate and validate...
Inventory regulation and control to a desired time-varying inventory level is accomplished via an accurate on line observer-based demand rate estimation, followed by a demand rate satisfaction effort incorporated on the production rate decision rule. An extended demand rate observer is shown to efficiently allow for production rate to accurately match highly fluctuating uncertain demand rates, with...
This paper investigates the trajectory tracking control of the nonholonomic wheeled mobile robot (NWMR) using nonlinear model predictive control (NMPC). By defining the tracking error in the NWMR's local coordinate, the tracking problem is formulated into standard NMPC framework. However, the standard NMPC algorithm is computationally demanding so that it is difficult for the real-time implementation...
Autonomous electric vehicle path following area has known wide improvement during the last previous years especially with the appearance of new sophisticated control algorithms. The main focus of these control algorithms is to guarantee high performance in term of stability and path tracking with small distance error. In this research, an overview about the most common technics used in autonomous...
Sperm activity is one of the important factors affecting male reproductive capacity. Computer assisted semen analysis (CASA) has a high clinical value for judging sperm motility. In this paper, sperm-related motion parameters were obtained by image preprocessing, dynamic and static target segmentation, minimum neighborhood matching sperm motions. In addition, a complete sperm trajectory detection...
The proposed hierarchical sliding mode control (HSMC) for the car-like automated guided vehicle (CLAGV) includes two parts: one is virtual control input (VCI), the other is sliding mode tracking control (SMTC) [1]. Moreover, a single software/hardware based platform develops the software for the control, image processing and trajectory planning algorithms, and the hardware for the control signal (e...
This paper investigates the coupled disturbance reconstruction, state estimation and trajectory tracking problems for a class of nonlinear systems. The sliding mode observer and the state feedback approaches are utilized to solve these problems. Considering only a partial of the system states are measured but the disturbances couple with time-varying parameters that the observer is designed by transforming...
Compared with Zhang dynamics (ZD) method, gradient dynamics (GD) method, which is intrinsically feasible and efficient to solve time-invariant problems, could have a simpler hardware implementation. In this paper, different from conventional type-Z0G1 controller in Zhang-gradient (ZG) framework, which uses gradient descent of input vector, a type-Z0G1 controller using gradient descent of state vector...
This paper addresses the problem of steering Underactuated Surface Vessels (USVs) along given paths. Due to dynamical uncertainty and ocean disturbances induced by unknown wind, waves and ocean currents, there exist some imperfections in dealing with this non-linear systems with traditional control algorithms. A novel trajectory following controller based on Active Disturbance Rejection Control (ADRC)...
In this paper is intended to control the entire flexible line using two wheeled mobile robot and two robotic manipulators. The mechatronics manufacturing line has no possibility of automatic feed with pieces and no automatic pickup of the scrap pieces from the storage station. The robotic manipulators are used for charging the buffer of the flexible line as well as emptying the storage station. These...
This paper presents a cascaded trajectory tracking controller and a control gains selection procedure for nonholonomic car-like wheeled mobile robots with steering and velocities controllers in the tracking control loops. The trajectory tracking controller enables stable tracking control of trajectories for the car-like mobile robots in the presence of the robot's velocity and steering control latencies...
Energy balanced control method for converters with natural trajectory tracking is presented in this paper, and is visualized to show converters' energy conversion inside converters. This paper specially designs and analyzes a single-phase full-bridge inverter based on energy balance with natural trajectory tracking. Natural trajectory tracking introduces a better dynamic response than the conventional...
This paper presents a path following controller for quadrotors to follow splines in the output space. The control pipeline includes utilization of a cascaded control architecture, generation of paths using quintic spline interpolation, transformation of coordinates using Frenet-Serret (FS) frames, and decoupling controllers for the transversal and tangential sub-systems. The result is a time-invariant...
A simple Line-Of-Sight (LOS) based trajectory tracking algorithm intended for underactuated vehicles is presented. Time parametrized trajectories in two dimensions are considered. Local exponential stability for straight trajectories and ultimate boundedness for general trajectories is shown for the guidance law error dynamics, using Lyapunov perturbation analysis. The results are verified in simulations...
This work implements two trajectory tracking control systems for a differential drive WMR (Wheeled Mobile Robot). The first control system employs an IO PD (Integer Order Proportional Derivate) controller, while the second uses a FO (Fractional Order) PD controller. The IO PD controller becomes a FO PD controller by making fractional the derivative term. That is, replacing the Laplace operator s by...
Three-degree-of-freedom trajectory tracking of the stratospheric airship is investigated. With a simplified planar dynamic model, an adaptive backstepping sliding mode controller is designed to keep the airship to globally asymptotically track a desired trajectory. Lyapunov functions are used to ensure the tracking performance when model parametric uncertainty and external disturbances exist. Simulation...
In this study, the trajectory tracking control problem of a 2 degrees of freedom robotic orthosis for the lower limb rehabilitation is discussed. The robotic orthosis is actuated by a pair of self-made pneumatic artificial muscles (PAMs) in an antagonistic configuration. A second order plus dead time (SOPDT) linear model is chosen for describing the antagonistic actuator behavior. In order to enhance...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.