Visual servoing of nonholonomic cart

This paper presents a visual feedback control scheme for a nonholonomic cart without capabilities for dead reckoning. A camera is mounted on the cart and it observes cues attached on the environment. The dynamics of the cart are transformed into a coordinate system in the image plane. An image-based controller which linearizes the dynamics is proposed. Since the positions of the cues in the image plane are controlled directly, possibility of missing cues is reduced considerably. Simulations are carried out to evaluate the validity of the proposed scheme. Experiments on a radio controlled car with a CCD camera are also given</p

Master assisted cooperative control of human and robot

A cooperative control approach between human and robot takes an important role to carry out various tasks in hazardous environments or space. In this case, a robot is operated based on the cooperation between direct human control and autonomous robot control. In this study, a neural network is introduced for cooperating process between human control and robot control in order to optimize the degree of cooperation of human and robot. The degree of participation of human operator into the control is determined based on a reference cooperative model which expresses desired human and robot cooperative form. The experiment has executed the contacting tasks for the various object walls using a two-degrees of freedom Cartesian robot. The results indicate the availability of the proposed cooperating method for the cooperative control of human and robot </p

Robust positioning control of pneumatic servo system with pressure control loop

The goal of this paper is to attain a robust positioning control of a pneumatic driving system. A positioning control system positively focusing on the pressure control is investigated from the view that the pressure control is indispensable for improvement of control performances. A disturbance observer is employed to improve the pressure response and compensate the influence of friction force and parameter change. Consequently the improvements of robustness against payload and of positioning accuracy have been attained </p

Development of Wrist Rehabilitation Equipment Using Pneumatic Parallel Manipulator

In this study, we aim at developing a mechanical device to support humans rehabilitation motion of their wrist joint instead of or to help a physical therapist. Pneumatic parallel manipulator is introduced as the mechanical equipment from a view that pneumatic actuators bring minute force control property owing to the air compressibility and parallel manipulator’s feature of multiple degrees of freedom is suitable for a complex motion of human wrist joint. Impedance control system is introduced to realize several rehabilitation modes. The validity of the proposed system is confirmed through some experiments.</p

Modeling and control of robotic yo-yo with visual feedback

Yo-yo is a toy made of two thick circular pieces of wood, plastic, etc., connected with a short axle that can be made to run up and down, by moving a string tied to it. Humans can play with a yo-yo without difficulty. However, developing a robot system that can play with a yo-yo presents a significant challenge to controller design, because the dynamics of the yo-yo are difficult to model precisely. Moreover, since the dynamics are not continuous and there are integral-type constraints on the hand trajectory, conventional continuous time feedback control theory does not work well. This paper present a model and a control scheme for robotic yo-yo with visual feedback. Experiments on a PUMA 560 are carried out to evaluate the validity of the discrete dime formulation and the controller design</p

Potential switching control in visual servo

Stability of feature-based visual servoing controllers proposed so far is local. The initial features far from the reference may converge to features different from the reference or, even worse, they may not converge. In this paper, the stability of feature-based visual servoing is considered by using potential. The stable region is visualized and artificial potential switching is proposed to extend the stable region</p

Application of rubber artificial muscle manipulator as a rehabilitation robot

The application of a robot to rehabilitation has become a matter of great concern. This paper deals with functional recovery therapy, one important aspect of physical rehabilitation. Single-joint therapy machines have already been achieved. However, for more efficient therapy, multjoint robots are necessary to achieve more realistic motion patterns. This kind of robot must have a high level of safety for humans. A pneumatic actuator may be available for such a robot, because of the compliance of compressed air. A pneumatic rubber artificial muscle manipulator has been applied to construct a therapy robot with two degrees of freedom (DOF). Also, an impedance control strategy is employed to realize various motion modes for the physical therapy modes. Further, for efficient rehabilitation, it is desirable to comprehend the physical condition of the patient. Thus, the mechanical impedance of the human arm is used as an objective evaluation of recovery, and an estimation method is proposed. Experiments show the suitability of the proposed rehabilitation robot system </p

Development of pneumatic human interface and its application for compliance display

The goal of this study is to develop a human interface that can display compliance for a human hand aiming at application in the field of virtual reality. A pneumatic parallel manipulator is introduced as a driving mechanism of the human interface, which yields the characteristic that the manipulator works as a kind of elastic body even when its position/orientation is under the control. Utilizing this elastic characteristic, a compliance display scheme is proposed. The validity of the proposed scheme is verified experimentally </p

Development of force displaying device using pneumatic parallel manipulator and application to palpation motion

&#60;P&#62;The goal of this study is to develop a mechanical system which display elastic characteristic like stiffness on the surface of human body aiming at applying to palpation simulator. Pneumatic parallel manipulator is employed as a driving mechanism, consequently, it brings capability of minute force displaying property owing to the air compressibility. Compliance control system without using force/moment sensor is constructed by introducing a disturbance observer and a compliance display scheme is proposed. The validity of the proposed scheme is verified experimentally. </p

Visual servoing with linearized observer

One of the most important problems in feature-based visual servoing is the slow sampling rate and the delay of the camera that can make the closed loop system oscillative or unstable easily. In the paper, a linearized observer that estimates the object velocity and updates the visual information with the joint sampling rate is proposed. Stability of the observer-based control system and effectiveness of the observer are verified by experiments on a PUMA 560 robot</p