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Direct drives with linear motors are attracting the attention of both industry and academia thanks to their advantages in terms of higher precision, higher acceleration/deceleration, and reduced dimensions. This paper presents a comparison between industrial PID controllers and state-of-art non-linear control strategies for accurate position tracking on a linear permanent magnet synchronous motor...
A pursuit-evasion differential game with bounded controls and prescribed duration is considered. The evader has two possible dynamics, while the pursuer dynamics is fixed. The evader can change its dynamics once during the game. The initial lateral acceleration of the evader is non-zero. The pursuer knows the possible dynamics of the evader, but not the actual one. The capture zone and the capture...
A lower limbs rehabilitative training robot was designed to improve walking ability of patients who suffer from impairment in locomotion after neurology injuries or aged persons who lack walking capability. The robot was fixed with four omni-directional wheels which can move within any radius in any direction. When the robot is running, some undetected uncertainty disturbances change its running trajectory,...
The problem of controlling load perturbed induction motors is tackled by means of an observer based robust discrete-time control. In this scheme, model uncertainties and external disturbances are included in a general additive disturbance input which is to be on-line estimated and subsequently rejected via the controller actions. The observer carries out the disturbance estimation, thus reducing the...
This article describes a new control scheme designed for a three-degree-of-freedom (3-DOF) flexible robot. The control scheme consists of a two multivariable control loops; the inner loop controls the position of the motors, and the external loop controls the tip's position and cancels the vibration. The outer control loop, as will be shown, is robust to tip mass variations. Simulations are carried...
This paper presents the design, implementation, and comparative analysis of two intelligent neural network based controllers employed for nonlinear dynamic compensation and adaptive trajectory tracking of a mobile robot system. The first control law is an integration of a backstepping controller with a neural network which is designed to learn the inverse dynamic model of the robot and to compensate...
In this paper, a robust fault-tolerant control strategy for constrained multisensor linear systems, subject to sensor faults and in the presence of bounded state and output disturbances is proposed. The scheme verifies that for each sensors-estimator combination, suitable residual variables lie inside pre-computed sets and selects the more appropriate combination based on a chosen criterion. An active...
In this paper, a constrained robust guaranteed cost tracking scheme for Wheeled Moving Robot (WMR) with actuator saturations is proposed. First, tracking error dynamics of WMR is represented by uncertain Tagaki-Sugeno (T-S) fuzzy model, where varying velocity in desired trajectory is look as uncertain parameter, so we can represent the T-S subsystem via Then constrained robust guaranteed controller...
Collision avoidance systems, whether for manned or unmanned aircraft, must reliably prevent collision while minimizing alerts. Deciding what action to execute at a particular instant may be framed as a multiple-objective optimization problem has explored methods of efficiently computing the that can be solved offline by computers. Prior work optimal collision avoidance logic from a probabilistic model...
The open-loop flexible modes identification of a high-speed and high-accuracy pick-and-place parallel robot is carried out based on two approaches: an ARMAX model and a subspace identification technique. Models of piezoelectric dynamics and disturbances can be obtained for many distinct operation conditions, allowing, in a future work, the conception of robust control laws.
In this paper, a new variable structure position control law for a Six Phase Induction Machine (6PIM) is proposed. The algorithm based on a time-varying switching line guarantees the existence of sliding mode since the beginning of the shaft motion. Indeed, the surface is initially designed to pass through the initial representative point and subsequently moved towards a predetermined desired surface...
This paper proposes a new control method for a three-degree-of-freedom flexible robot. In the model, the mass is assumed to be concentrated at the end of the robotic arm. The main feature of the method is that it consists of two nested control loops: the inner one controls the angular positions of the motors and the external one the tip's position and cancels the vibration. The outer control loop,...
This paper proposes multivariable robust control for a gait trainer for people with walking disability. The gait trainer composes of linkages and motors, which drive the linkages to produce preferred gait traces. To simplify the traditional motor control, the tracking error and motor current are feedback for control design to regulate the motor voltage. First, the transfer function matrices of the...
This article describes the design of a linear observer-linear controller-based robust output feedback scheme for output reference trajectory tracking tasks in an input delayed omnidirectional mobile robot. The unknown, possibly state-dependent, additive nonlinearity influencing the tracking error dynamics, is modeled as an absolutely uniformly bounded, additive unknown “time-varying disturbance” input...
This paper considers the problem of controlling both the planar position and the orientation of an underactuated airship with a reduced number of actuators in the presence of a unknown persistent wind disturbance. The airship is a nonholonomic system described by a set of nonlinear equations and the dynamics are subjected to bounded uncertainties. A smooth and time-varying coordinate transformation...
In this paper we formulate and solve optimal control problems for power generating kite systems. Here, the kite generates energy by periodically pulling a generator on the ground while flying fast in a crosswind direction. We are searching for an intrinsically open-loop stable trajectory such that the kite generates as much power as possible without needing feedback, while neither the kite nor the...
This paper presents a trajectory tracking control design which provides the essential spatial-temporal feedback control capability for fixed-wing unmanned aerial vehicles (UAVs) to execute a time critical mission reliably. In this design, a kinematic trajectory tracking control law and a control gain selection method are developed to allow the control law to be implemented on a fixed-wing UAV based...
In this paper, an Estimator/Observer Swapping system is proposed, for the surface Permanent Magnet Synchronous Motor (PMSM), to overcome position observability problems at zero speed which is an unobservable state point. The designed observer based on Higher Order Sliding Mode (HOSM) is used in order to ensure the robustness against disturbances and to avoid the chattering phenomenon which is inherent...
Since the longitudinal, lateral, and yaw dynamics of front steering vehicles are represented by nonlinear coupled equations, it is not easy to derive the explicit nonlinear controller of both steering angle and driving force for the perfect path-following control. In this paper, a novel and robust sliding mode controller for vehicles with coupled full dynamic model is presented. Comparing with the...
This article presents a strategy of haptic guidance for training based on a sliding model control law for path planning, designed from passivity theory, applied to haptic devices modelling as manipulators robots with contact task, considering the human operator in the control loop. The experiments were developed with the PHANToM premium 1.0 haptic device and a closed path planning in its space of...
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