The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In this study, we achieve haptic communication between different structures. In haptic communication, tactile sensation is transmitted to a remote place by cooperating robots. Conventional haptic communication is implemented under the assumption that the masses of the actuators are equal. We have found that haptic communication system is a kind of position/force hybrid control system and that it is...
This paper presents the technological achievements in realizing the force feedback in surgical robots. No force sensor is used in sensing the force. Disturbance observer and its variant, reaction torque observer is used to detect the force. Bilateral control is used to transmit vivid sensations from the forceps end to the surgeon.
This paper proposes two methods for position constrained bilateral control. The constraint is given by coordinate transform and additional compensators or command modification methods are not necessary in these methods. The constraint therefore does not destabilize a system and does not nonlinearize it. A difference of the proposed two methods is priority of tasks. The first one ensures slave position...
This paper proposes a method for composition of a task hierarchy as an example of oblique coordinate control. As a primary task, position limitation is implemented and bilateral control is realized secondary. This hierarchy is simply given by a multiple of coordinate transform matrices and the problem can be regarded as position-force hybrid controller in oblique coordinate. Thus, the interference...
A motion reproduction system with haptic information for different environment location is proposed in this paper. In recent years, save and reproduction of human motion have been researched. Using a motion save system, position and force of the human motion are able to be saved as haptic information. In the conventional reproduction method, the reproduction of the human motion is not applicable when...
A controller for oblique coordinates is proposed in this paper. In an oblique coordinate, certain vector is expressed by two forms. One is a covariant vector, the other is contravariant vector. Usually, position is described by a contravariant vector, and force is given by a covariant vector. In order to realize hybrid control in a oblique coordinate, position and force should be unified into same...
In this paper, a real-time walking trajectory generation method at constant body height in a single support phase for three-dimensional biped robots is proposed. An analytic solution of a body trajectory was obtained from a ZMP (zero-moment point) equation of a body and a swing leg trajectory. Real-time body trajectory is generated based on an analytic solution. This body trajectory is applied, the...
In this paper, modal transform method for cooperation working is proposed. With this method, the work is simply described by modal mass and arbitral number and location of robots are able to be controlled by conventional hybrid controller. Furthermore, rotation by linear actuators, one of the most important propositions in this research, is considered. Position, angle, force and torque are transformed...
In this paper, real-time environmental recognition method is proposed. With this method, location of the contact points are described in three dimensions and directions of the forces are also described in three dimensions. At first, modes of the contact points are divided into two modes; ldquoforce moderdquo and ldquomoment moderdquo. After that, ldquoexternal moderdquo and ldquointernal moderdquo...
In this paper, a parameter design for ZMP (Zero-Moment Point) disturbance observer of biped robots is proposed. ZMP disturbance observer is used for the walking stabilization of biped robots. A decision method of six parameters is based on the stability and the performance. Relation between the parameters and the performance is shown. Gains of the position compensation and the acceleration compensation...
A dynamic force controller based on momentum is implemented to the redundant system in this paper. With this method, the centrifugal and Coriolis terms are eliminated from the system and precise and stable force control is realized. Firstly, force control based on momentum is described. This controller does not have any singular points and is able to be applied to dynamic state. A null space controller...
A stability analysis of force control based on momentum is presented in this paper. The inertia! force which makes the robot unstable such as centrifugal and Coriolis force is strictly modeled with this controller. Hence, the stability is improved. This fact is shown by an analytical approach with the transfer function. In order to increase response tracking capability, how to compose force feedforward...
A decoupling motion controller based on momentum is presented in this paper. Firstly, force control based on momentum is described. This controller does not have any singular points and is able to be applied to dynamic state. Moreover, inertial force which has been treated as disturbance such as centrifugal and Coriolis force is modeled with this method. Then, position and force vector is united in...
There are two types of force control system, force control with inverse Jacobian matrix and transpose Jacobian matrix. Both of the controllers, however, have a defect. The characteristic of the former controller is that it has singular point due to inverse Jacobian matrix. At this point, motion of a robot becomes unstable. On the other hand, with transpose Jacobian matrix, it is assumed that the motion...
Robots tend to be unstable at contacting environment, since robots receive high order disturbance like a impact force. In order to continue stable motion, robots should not only track to command value, but reduce the impact force. In many conventional methods, impedance control is applied to these kinds of problems. However, there is a problem that robustness of position control may be low with the...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.