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This paper introduces a class of reconfigurable parallel robots consisting of a fixed base and a moving platform connected by serial chains having RRPS (Revolute-Revolute-Prismatic-Spherical) topology. Only the prismatic joint is actuated and the first revolute joint in the chain can be locked or released online. The introduction of these lockable joints allow the prismatic actuators to maneuver to...
For the typical non-linear robot control system, this paper proposes a class of sliding mode variable structure control method (SMVSC) based on RBF neural network, and the controller's output is added a low-pass filter. A two-joint robot is the research object, This method apply a powerful learning and processing power of RBF network as the sliding mode controller for uncertain part, and resolves...
This paper presents a new design of haptic device which combines the spherical parallel structure with the serial link configuration. The spherical configuration offers 3DOF for the positioning its platform where a 3DOF serial link is connected. The moving platform is connected to the ground through a passive and active spherical joint configuration. As such, the passive joint can contribute in supporting...
A novel 6-DOF parallel manipulator composed of two limited-DOF manipulators is proposed in this paper, the degree of freedom (DOF) of this manipulator is analyzed and the position kinematic modeling is established. The Jacobian matrix is derived by vector loops equations. The workspace is determined considering the interference check by the numerical method. Furthermore, the performance of the mechanism...
This paper presents the ground work prepared for turning a bucket wheel reclaimer (BWR) into a robotic arm for operation automation. BWR has been widely used in dealing with bulk materials by removing them from the conveyor and stack them as well as to load stacked materials onto the in-feed conveyor, such as in mining industry. Generally speaking, current BWRs are manually operated, remotely operated,...
As space robots gain more and more importance in space operations, it was becoming imperative to understand their distinctive dynamics. The dynamics model of the space flexible robots is very complex, and the differential equation derived from dynamics was solved difficultly and slowly. In this paper the dynamics of space flexible robots was discussed, and the fast efficient integration method was...
In this paper, the control problem, in a 3D cartesian space, of camera-in-hand robotic systems is considered. In this approach, a camera is mounted on the robot, at the hand, which provides an image of objects located in the robot environment. The aim of this approach is to move the robot arm in such a way that the image of the considered object, a sphere in our case, coincides with the center of...
The current discussion on physical human robot interaction and the related safety aspects, but also the interest of neuro-scientists to validate their hypotheses on human motor skills with bio-mimetic robots, led to a recent revival of tendon-driven robots. In this paper, the modeling of tendon-driven elastic systems with nonlinear couplings is recapitulated. A control law is developed that takes...
Predictive function control strategy of the single-link manipulator with flexible joint is presented. The design process includes following three steps. First, the basic idea of feedback linearization is to construct a nonlinear control law as a so-called inner loop control which, in the ideal case, exactly linearizes the nonlinear system after a suitable state space change of coordinates. A second...
The main objective of this paper is to introduce a simulation platform in order to evaluate a control structures using the performance index; additionally, the simulator has the capacity of described the behavior of the prototype according to the control structure that is evaluated showing the results in graphical form.
The main objective of this paper is to control the position of a robot manipulator by means of the implementation of a new control scheme based on the combination of hyperbolic trigonometrical functions. In order to accomplish the control we used the method of shaping energy; and by means of the Lyapunovpsilas theory its stability is demonstrated formally. It is important to compare the functionality...
A constraint-based behavior fusion mechanism is proposed. The behavior-based concept is suitable for robots in a dynamic changing environment. However, this concept suffers from two major restrictions: re-usability of the behaviors and deliberation between the behaviors. Because of this, complex tasks are still challenging for behavior-based systems. In the control of sensor-based robots, the constraint-based...
Most existing approaches so far on position/force control of constrained robots always suffer from the complexity of the arm model that may cause difficulty in practical application. In this paper, a robust joint-model-based controller is proposed to deal with the problem of hybrid position/force control for constrained robots. The development of the controller is based on a novel formulation of the...
A new approach of fast collision-free motion planning for underactuated robots based on genetic algorithm is proposed. The collision avoidance problem is formulated and solved as a position-based force control problem. Virtual generalized force representing the intrusion of the arm into the obstacle dangerous zone is computed in real time using a virtual spring-damper model. The partly stable controllers...
In this paper, a recurrent neural network (termed, dual neural network) is revisited and applied to the online joint angle drift-free redundancy-resolution of a five-link planar robot manipulator. To do this, a drift-free criterion is exploited in the form of a quadratic function. In addition, the drift-free scheme could incorporate multiple joint physical limits such as joint limits and joint velocity...
This paper presents a simplified primal-dual neural network based on linear variational inequalities (LVI) for online repetitive motion planning of PA10 robot manipulator. To do this, a drift-free criterion is exploited in the form of a quadratic function. In addition, the repetitive-motion-planning scheme could incorporate the joint limits and joint velocity limits simultaneously. Such a scheme is...
The control problem of coordinated motion of free-floating dual-arm space robot with external disturbance is discussed. Combined the linear momentum conversation and the Lagrangian approach, the full-controlled dynamic equations of free-floating space robot with dual-arms is established and then inverted to the state equation for control design. Based on the terminal sliding mode control (SMC) technique,...
This paper applied a new concept of a nonlinear model reference PID controller for a planar robot arm. The controller consists of two second order differential equations, each in terms of the angle error of a single joint from the designed trajectory. The coefficients of each differential equation are specifiable giving the ability to specify the behavior of the robot. Simulations are presented that...
In this paper we will study dynamical modeling of a parallel robot Hexa using Lagrangian equation of the first type. Because of complexity and nonlinearity of parallel robotspsila relationships few works are done on their dynamical modeling. Although Newtonian approach is a straightforward method, it may not directly result in a suitable model for most of famous control schemes such as robust, adaptive...
Force feedback control is essential for humanoid robot as it is important for the robot to work in the human-robot mixed environment. This article proposes improved task-oriented force feedback control methods for humanoid robot which are based on the robot control system proposed by Oussama Khatib. The methods are improved in three parts: joint forces optimization, combination of joint forces and...
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