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Robots can adapt strides according to ground conditions and walk stably in different environments. This study uses fuzzy logic control and Linear Quadratic Regulator (LQR) control theory on biped robot system to achieve the development of balanced and fast footsteps. Traditional controllers are designed according to mathematical models of physical systems, while fuzzy controller is a physical system...
This paper represents the Lyapunov stability study for the wheeled mobile robot C3P based on a non-linear and complex mathematical model. The candidate Lyapunov function used in this work is extracted from the robot kinetic energy equation, which includes the robot dynamics and kinematics models. Such function contains uncontrolable and unpredicticable variables that yeild to very complicated and...
The main contribution of this paper is to present and discusses a new approach for development of a kinematics model and control strategy for a Nonholonomic Wheeled Mobile Robot WMR. Dynamic model is involved, the linearization of the model is also presented, and stability analysis is discussed. Extensive simulation results for the proposed controller are presented.
A decentralized control law using a backstepping scheme is proposed to deal with a leader follower multiple robots structure. The coordination strategy combines the leader follower control with the decentralized control. In fact, in the proposed approach, each follower robot only needs the information exchange with its connected neighbors and does not assume the existence of direct communication channel...
A passive walker is a kind of robot that consumes low energy through body dynamics. However, it is difficult to stabilize it in various environments, because it is hard to synchronize the rocking period of the robot with the swing leg period. This research developed an online period control method to solve the stability problem and realize ascending slope for a biped quasi passive walker. A mechanical...
The identification method for industrial manipulators considering physical consistency such as positive definiteness of inertial parameters has been developed, however it has to solve the quadratic programming with the non-linear inequality constraints. In identifying the large DOF systems like humanoid robots, the converged solution is difficult to be obtained. In this paper, we propose the method...
This paper proposes passivity-based controllers for periodic motions of multi-joint robots with impact phenomena. Even the robot motions with impact phenomena have complex dynamics, we try to analyze stability of the controlled systems by adopting some assumptions and using Lyapunov-like functions. At first, we present a passivity-based feedback controller. Secondly, we present a repetitive controller...
Medical-technical robotic systems are typical examples in which external contact forces on a system play an important role in the system dynamics. Mathematical modeling of these systems is challenging due to a variety of reasons. Mathematical models for the described class of systems contain differential equations with an associate algebraic equation, which outlines constrained system dynamics. Such...
This paper proposes repeatedly direct kinematics (RDK) algorithm to trajectory generation of a multi-joint robot in lift-down movements. For trajectory generation of the multi-joint robot, three constraints are considered. They are no turnover, the joint limits and the torque limits of the robot. Safety factor is set in order to ensure the stability of robot. The emphasis of the study is placed on...
In this paper, a neural network control based on optimal quadratic regulators is developed for the stabilization of constrained nonlinear robotic systems. This method of robotic control is performed by adding an optimal control, generated from the dynamics of the position error, to a neural control, estimated through a three layers neural network. Solving an algebraic Riccati equation, solutions of...
A dynamics model for a hexapod robot is developed in this paper which avoids extra calculations to yield a compact set of dynamic equations. To this end, foot interaction with the ground is modeled based on a compliant model, and a force distribution method is implemented in finding required friction forces. This leads to minimum slippage possibility and energy consumption. Furthermore, a scheme is...
This paper analyzes cause of control errors for 5 DOF exoskeleton upper-limb rehabilitation robot. Based on the method of typical repetitive control, let multiple improved repetitive control loops with filtering parallel embed into closed-loop of control system in order to eliminate motion error of rehabilitation robot with multi-channel periodic input signal. The simulation results show that the...
This paper represents the posture stabilization of a Skid Steer Wheeled Mobile Robot (SSWMR). Although, in mobile robots lateral skidding of the wheels occurs when turning at high speed, wheels of a SSWMR laterally skid in every rotational maneuver even for low speeds yielded the non-skidding nonholonomic constraint to be violated. In order to compensate the effects of parameter uncertainties, an...
The geometric function of the target path was used to define the tracking error, converting the path following problem under study into a problem of output regulation. An exponential stable tracking control law was therefore derived adopting input-output linearization approach and back-stepping technique. Thanks to the exponentially decaying terms added to the desired geometric path, the singularity...
This paper establishes the three-wheel mobile robot kinematics model based on the research on its structure and working principle. A novel algorithm is developed for the trajectory tracking and posture stabilization of three-wheel mobile robot using contractive model, which address stability by adding terminal state penalties in the performance index and imposing constraints on the terminal state,...
Dynamics and control of a flexible space robot capturing a static target was presented in this paper. The dynamics model of the robot system is derived with Lagrangian formulation. The control method of flexible space during capturing target was discussed. Finally, some simulation tests have conducted that the proposed method can assurance the stability of capturing the object and reach a good effectiveness...
This work implements a visual-servo control that generates motor commands for a mobile robot according to a visual target. This robot is also the leader of a robot team that uses a centralized, non-linear and stable control to keep group formation. Therefore, whenever the target moves, the leader moves to correct its position and orientation, also forcing the whole team to move in formation. The combination...
The paper presents a method for decentralized flocking and global formation stabilization for a network of unicycles described by the standard kinematics equations with hard constraints on the vehicles linear and angular velocities.
In this paper, we consider the problem of navigation and guidance of a Dubins-like wheeled robot towards a steady or maneuvering target with range-only information. We propose a range-based sliding mode controller through which the robot follows a target with a constant speed while preserving a predefined range margin from the target. Mathematically rigorous proof of convergence and stability of the...
A unified formation control policy is presented. From the trajectory and shape aspects, the group formation control problem is decoupled into the desired trajectory tracking problem of each individual, and the consistency of stability and optimality between these two problems are proved. The overall criterion and decomposed criterions to evaluate the formation performance are designed. The decomposed...
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