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This paper deals with a sensorless control approach of a lightweight electric actuator. Force and motion control are necessary to perform manipulation tasks with object interaction of different stiffnesses. The controller must ensure stability in a wide range of rigidity, particularly in soft contact cases. The approach proposed here is based on a force/position control scheme. First, a nonlinear...
The single robot joint, which contains a DC torque motor and a harmonic reducer, was designed. And sliding mode control strategy by the self-adaptive adjustment of the sliding parameter ε was proposed in this paper. This control strategy can adaptively adjust ε by switching variables and their derivatives according to the system. It is applied in the control of robot joint to solve the contradiction...
This paper describes the design and development of a new actuator with adjustable stiffness (AwAS) which can be used in robots which are necessary to work close to or physically interact with humans, e.g. humanoids and exoskeletons. The actuator presented in this work can independently control equilibrium position and stiffness by two motors. The first motor controls the equilibrium position while...
In our current research, we are developing a robotic walker system with standing, walking and seating assistance function. Our developing system is based on a walker which is popular assistance device for aged person in normal daily life and realizes the standing and seating motion using the support pad which is actuated by the novel assistance manipulator mechanism with four parallel linkages. In...
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...
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...
Based on Extended State Observer (ESO), a new robust control strategy with backstepping design for modular manipulators is brought forward in this paper. Firstly, considering the motor dynamics of the robot manipulator, the robot manipulator dynamics can be separated into two subsystems named as the robot joint subsystem and the motor subsystem. Then, a third-order and a second-order ESO are respectively...
Adaptive fuzzy control scheme is given and applied to position control of a single finger joint for a dual-thumbed hand. The dynamic model of the hand is established. The fuzzy control rules based on the characteristics of human being grasping is determined. The effectiveness of the presented control scheme is proved through simulation experiment for a dual-thumbed hand. The experiment results show...
This study focuses on the development of a direct adaptive fuzzy-neural-network control (DAFNNC) for an n-link robot manipulator to achieve high-precision position tracking. In general, it is difficult to adopt a model-based design to achieve this control objective due to the uncertainties in practical applications, such as friction forces, external disturbances and parameter variations. In order...
This paper presents the control architecture and preliminary experimental results of a high performance parallel robot used for ankle rehabilitation. The goal of this work was to design suitable control algorithms for diagnostic, training and rehabilitation of the ankle in presence of musculoskeletal injuries. A position control scheme is used for patient-passive exercises while an admittance control...
An Intelligent Control (IC) method based on MLP neural networks and Through Model Lemma (T.M.L.) is implemented to control the position of a Low Earth Orbit (LEO) satellites tracking earth station antenna. This approach relies on two different multilayer neural networks with delayed inputs, for the purpose of identification and control. Nonlinear term in motors caused by friction is not necessary...
This paper presents an amphibious snake-like robot's design and its omnipotent locomotion ability both on the land and in the water. This amphibious snake-like robot, mainly composed by 9 modular universal units, is waterproof and can move smoothly in the water while pressurized with O-rings and other essential accessories. In this paper, we concentrate on the gait diversity of the amphibious snake-like...
Human hands are capable of many dexterous grasping and manipulation tasks. To understand human levels of dexterity and to achieve it with robotic hands, we constructed an anatomically correct testbed (ACT) hand which allows for the investigation of the biomechanical features and neural control strategies of the human hand. This paper focuses on developing control strategies for the index finger motion...
This article presents the mechanical design, hardware architecture and control scheme for critic joints in biped robots. A dynamic simulator was developed in order to quantify torque and currents motor requirements for different gait trajectories. The particular characteristics of biped robots has led to an important design effort in transmission systems, which is deeply discussed before presenting...
This study focuses on the development of a fuzzy-neural-network velocity sensorless control (FNNVSC) scheme including a nonlinear observer and a fuzzy-neural-network (FNN) controller for an n-link robot manipulator to achieve high-precision position tracking. This nonlinear observer is used to estimate joint velocities of the robot manipulator. Then, a four-layer FNN is utilized for the major control...
This work presents the design and evaluation of knee joint controllers for an above-knee prosthesis. The prototype is a three degree of freedom prosthesis which is planned to be controlled in part by EMG thigh signals, in part by a predictive trajectory generator based on multisensorial data such that the foot can be correctly positioned with respect the floor. There is described a simplified non-linear...
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