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Surgeons are using robots as a tool to increase surgery accuracy and decrease procedure times. One of the main problems in robotic assisted orthopedic surgery is the force control in manipulator robots. It always has been subject of great study and interest in the scientific community, where the most common approach is to consider it as a hybrid control problem, due to their complexity and non-linearities...
In this paper, geometric nonlinearity of a flexible link is considered for dynamic modeling of free-floating space manipulators. The system dynamics is derived by Lagrange theorem in conjunction with the assumed modes method. By reducing some parameters, dynamic equations of small deflection is obtained for control system design. For position control design, modified partial feedback linearization...
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...
This article is aimed at presenting a technique to generate bipedal walking trajectories that can be applied to humanoid robots. The proposed method is based on maintatining the dynamic balance by using the ZMP criterion throughout single support phases. To be able to reach this goal, we employed ZMP equations in spherical coordinates, so that the rate change of intrinsic angular momentum terms in...
Shape Memory Alloy (SMA) wires are currently employed in robotics, as well as in actuators for various fields such as prosthetic limbs and medical equipments, where they can be a good alternative to traditional actuators. SMA wires are particularly suitable for simple designed small devices with and high power-to-weight ratio, and are also an optimum solution when employed as sensors and actuators...
Humanoids are increasingly used in the service sectors around the world to work with, or assist humans. However current humanoid designs place limitations on direct engagement with the human in terms of safety and usability. In this paper, we present an approach for the control of hybrid, high-speed and safe human-robot interaction systems with highly non-linear dynamic behavior. The proposed approach...
Tendon controlled robots with nonlinear mechanical tendon stiffness are becoming more and more popular. With the appropriate actuation, the joint position and the stiffness between motor and link side can be prescribed at the same time. In this paper, the modeling of tendon-driven elastic systems with nonlinear couplings is recapitulated. Based on the Immersion and Invariance (I&I) framework a...
In this paper we presents two new 0-flat normal forms. It deals with sufficient geometrical conditions which enable us to conclude if a given nonlinear controllable dynamical system can be transformed, by means of change of coordinates, to one of these normal forms. In the same way it gives an algorithm to compute the flat outputs. As an illustration to the proposed approach, a trajectory tracking...
This paper investigates a tip angular position controller for a single-link flexible robot arm that considers the passivity of the flexible robot arm on the basis of a distributed parameter system. A Lyapunov function related to the total energy of the distributed parameter system is considered to derive a direct output feedback control law for the flexible robot arm. To achieve tip angular position...
In this paper a state feedback controller is designed for Rigid Link Electrically-Driven (RLED) manipulators actuated by a brushed DC (BDC) motors based on joint velocity estimation. The observer based controller is in fact a model based controller but it can be shown practically that the method is robust against parametric uncertainties. Initially pseudo-velocity filter is proposed to estimate the...
In order to aid walking and limb rehabilitation training, a four-degree pelvic pose and position control mechanism of walking aid robot is discussed based on the motion laws of human pelvic. By applying modified D-H method, a kinematical coordinate system of the pose and position control mechanism is set up and the forward and inverse kinematics models are also built up. After the design of control...
This paper deals with the application of the sliding mode control technique on the position servo system for a multifingered hand. The configuration of the hand system is described. The state equations of a single finger joint are presented based on dynamic model. Sliding mode controller was also determined. The method of alleviation chattering is discussed. The more satisfactory results are obtained...
The Lower-limb Power Assisted Robot is a typical exoskeleton power assistance device, which is worn on the user's lower extremities. It can help the elderly and the infirm walk independently. According to the characteristics of human lower extremity joints, a robot with four-bar knee joint whose pelvis and knee joint are driven by the motor-driven screw-nut body is designed. Employing the Denanit-Hartenberg...
This paper suggests a novel reaction force control in a robot manipulator by position feedback, motivated by the analysis of human musculoskeletal system. First, we suggest an analogy between a muscle force characteristic and two-degree-of-freedom control input structure so that the complicated human muscle structure can be reflected in robot manipulator control: reaction force generated by the viscoelasticity...
In this paper the method used to implement the natural human gait for a humanoid robot is presented. This work is part of the humanoid robot project called Archie. The project Archie started on 2004 in the Institute of Handling Robotics and Technology at Vienna University of Technology. The aim of this project is to build a robot that can imitate human's basic activities such as walking. In this work...
The shotcreting robot has 8 joints including 3 joints coupled with others on the shotcreting robot. This paper set up the Denavit-Hartenberg Frames and deduced the kinematic equations with extra three constrain equations to decouple the linked motions. The unique analytical solution of the inverse kinematic equations was educed, which provided foundation for further research on trajectory plan, dynamics...
This paper presents an approach to the control of the KNTU CDRPM using an integrated control scheme. The goal in this approach is achieving accurate trajectory tracking while assuring positive tension in the cables. By the proposed controller, the inherent nonlinear behavior of the cable and the target tracking errors are simultaneously compensated. In this paper asymptotic stability analysis of the...
This paper presents the manipulator with the new joint which can passively switch free state to drive state and vice versa. The manipulator with the free-state joint is categorized as a system subjected to a nonholonomic constraint; hence, its smooth feedback control cannot be implemented. In this paper, the issues on its control are clarified through the test with the experimental setup of the manipulator...
This paper presents a novel planar three-degree-of-freedom pendulum-like underactuated robot. The robot consists of an end-effector with an actuated arm suspended on a cable wound on a reel. The robot can achieve full planar point-to-point motion (position and orientation) with zero-velocity landing by swinging itself as children do on playground swings. The equations of motion of the underactuated...
This paper discusses how mobile manipulators with an under-actuated vertical arm can be designed to be differentially flat. The property of differential flatness is achieved by appropriate inertia redistribution of the vertical arm and a wide range of under-actuation becomes possible. As a result of having the flatness property, the under-actuated mobile manipulators are capable of executing point-to-point...
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