In this study, a method to enhance the accuracy of overlapped etched track analysis is proposed. Counting tracks by eye is not an easy task and automated tracks counting systems are attractive key for this problem. This method supplements the deficiencies of the conventional track analysis method. A computer programme named KoreaTech Track Measurement System written in C++, which is the authors’ previous method, has been upgraded. In the proposed track analysis method, the track images captured from solid state nuclear track detectors are geometrically analysed and the number of tracks is counted. A damaged etching track shape can be restored on the track image to improve the analysis accuracy. For track restoration, the effective points are differentiated from the damaged track image. The track image is then restored by estimating the radii (small object removal) or their axis (ellipse, circle and non‐circle) using the RANdom sample consensus method. Using the restored track image, the track parameters are obtained from the ellipse and then approximated to the contour of the track image to analyse the track image. Then, the total number of tracks including the overlapped tracks is counted. To verify the proposed track analysis method, experiments using actual etching track images are conducted and the results are discussed.

Two human-robot interactions, including a haptic interaction and a teleoperated interaction, are explored with a new exoskeleton-type masterarm, in which the electric brakes with the torque sensor beams are used for force reflection. In the haptic interaction with virtual environment, the masterarm is used as a haptic device and tested to examine how the resistant torque of the electric brake for the force reflection is implemented in contact regime prior to conducting the teleoperated interaction. Two types of virtual environments, a rigid wall with high stiffness (hard contact with 10 [KN/m]) and a soft wall with low stiffness (soft contact with 0.1 [N/m]), are integrated with the masterarm for the haptic interaction. In hard contact, large force is fed back to the human operator, and makes the human operator hardly move. The electric brake with the torque sensor beam can detect the torque and its direction so that it allows free motion as well as contact motion by releasing or holding the movement of the operator. The experimental results show how the electric brake is switched from contact to free regime to allow the operator to move freely, especially when the operator intends to move toward the free regime in contact. In soft contact, the force applied to the human operator can be increased or decreased proportionally to the torque amount sensed by the torque sensor beam, thus the operator can feel the contact force proportional to the amount of the deformation during the contact. Finally, the masterarm is integrated with the humanoid robot, CENTAUR developed at Korea Institute of Science and Technology to conduct a pick-and-place task through the teleoperated interaction. It is examined that the CENTAUR as a slave robot can follow the movement of the operator.

We propose a new time-domain passivity observer (PO) and passivity controller (PC) which removes the constant-velocity assumption during one sample time, which was used in our previous PO/PC approach. A new sampled-time definition of passivity is introduced, and this new definition is compared with the previous sampled-time definition of passivity. Through this comparison, we propose the more accurate PO/PC approach. The proposed new PO/PC approach is applied to the "Excalibur" haptic interface system with very high stiffness (K = 120 kN/spl middot/m) virtual environment, and stable contact is demonstrated.

We propose new time domain passivity observer (PO) and passivity controller (PC) which removes the constant velocity assumption during one sample time, which was used in our previous PO/PC approach. A new sampled time definition of passivity is introduced, and this new definition is compared with the previous sampled time definition of passivity. Through this comparison, we propose the more accurate PO/PC approach. The proposed new PO/PC approach is applied to "Excalibur" haptic interface system with very high stiffness (K = 120 KN/m) virtual environment (VE), and stable contact is demonstrated.

A new concept of the exoskeleton-type masterarm, composed of serial links, is introduced in the paper. To provide maximum range of human motion, several redundant joints are added to the serial links. In order to reduce the number of joints to be measured, kinematics of serial links was taken into consideration in design. Three measurable, controllable joints and three redundant free joints are used for the upper arm (shoulder), similarly to the forearm (wrist) while one measurable, controllable joint is used for the elbow. In particular, a torque sensor beam is designed for fine force reflection using the strain gauge. It detects the torque as well as its direction applied by the human operator, which allows the electric brake to be used as an actuator for force reflection. The electric brake constrains the joint movement so that the operator can feel the force. This electric brake outperforms the motor in terms of torque/weight ratio and makes the device light and compact. This masterarm measures the movement of the operator's arm precisely, and its can be used for teleoperation with a slave robot, or as a motion planner for an industrial robot.

In this paper, two major practical issues are studied to improve the performance of a new energy based method of achieving stable, high performance haptic interface control. The first issue is related to resetting the amount of energy accumulated in the passivity observer for faster operation. A heuristic method is derived and experimentally tested for the resetting and it is shown to help the PC to operate sooner when the system gets active. The second one was noise in velocity measurements being magnified into audible force signals by the controller. This issue was addressed by the introduction of a velocity threshold and it is verified that the velocity threshold makes the PC more free from the noise effect at low velocity. Experimental results are presented for the "Excalibur" haptic device.