• Journal of the Korean Institute of Intelligent Systems
• /
• v.19 no.4
• /
• pp.451-456
• /
• 2009

In this paper, a virtual force is generated and fed back to the operator to make the teleoperation more reliable, which reflects the relationship between a slave robot and an uncertain remote environment as a form of an impedance. In general, for the teleoperation, the teleoperated mobile robot takes pictures of the remote environment and sends the visual information back to the operator over the Internet. Because of the limitations of communication bandwidth and narrow view-angles of camera, it is not possible to watch certain regions, for examples, the shadow and curved areas. To overcome this problem, a virtual force is generated according to both the distance between the obstacle and the robot and the approaching velocity of the obstacle w.r.t the collision vector based on the ultrasonic sensor data. This virtual force is transferred back to the master (two degrees of freedom joystick) over the Internet to enable a human operator to estimate the position of obstacle at the remote site. By holding this master, in spite of limited visual information, the operator can feel the spatial sense against the remote environment. It is demonstrated by experiments that this collision vector based haptic reflection improves the performance of teleoperated mobile robot significantly.

• Journal of Institute of Control, Robotics and Systems
• /
• v.12 no.2
• /
• pp.161-167
• /
• 2006

In this paper, lateral force control of a mobile robot with slip is presented. First, the bicycle model of a mobile robot is derived for the front steering. Second, impedance force control algorithm is applied to regulate contact force with environment. The desired distance is specified conservatively inside the environment to guarantee to make contact. Different stiffness of environment has been tested for force tracking task. Simulation results show that the proposed control algorithm works well to maintain desired contact force on the environment.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.6
• /
• pp.667-673
• /
• 2010

This paper proposes a control method based on a pseudo-impedance model to control the motion of biped robots walking on an uneven surface. The pseudo-impedance model simulates the action of the ankle of a foot landing on the ground when a human walks. When the foot is in contact with the ground, the human ankle goes through two different phases. In the first phase, the human exerts little or no effort and applies no torque on the ankle so that the orientation of the foot is effortlessly and passively adjusted with respect to the ground. In the second phase of landing, the ankle generates a significant amount of torque in order to rotate and move the main part of the human body forward and to support the weight of the human; this phase is called the weight acceptance phase. Computer simulations of a 12-DOF biped robot with a 6-DOF environment model were performed to determine the effectiveness of the proposed pseudo-impedance control. The simulation results show that stable locomotion can be achieved on an irregular surface by using the proposed model.

• Journal of Institute of Control, Robotics and Systems
• /
• v.20 no.8
• /
• pp.801-806
• /
• 2014

LAS (Laparoscopy Assisted Surgery) has been substituted alternatively for traditional open surgery. However, when using a commercialized robot assisted laparoscopic such as Da Vinci, surgeons have encountered some problems due to having to depend only on information by visual feedback. To solve this problem, a haptic function is required. In order to realize the haptic teleoperation system, a force feedback and bilateral control system are needed. Previous research showed that the perturbation value estimated by a SPO (Sliding Perturbation Observer) followed a reaction force that loaded on the surgical robot instrument. Thus, in this paper, the force feedback problem of surgical robots is solved through the reaction force estimation method. This paper then introduces the possibility of the haptic function realization of a laparoscopic surgery robot using a bilateral control system. For bilateral control, the master uses an impedance control and the slave uses a SMC (Sliding Mode Control). The experiment results show that a torque and force sensorless teleoperation system can be implemented using a bilateral control structure.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.14 no.5
• /
• pp.259-267
• /
• 2019

This paper proposes a structure of a variable impedance control system based on sensor-less external force estimator of industrial manipulators for cyber physical production systems (CPPS). To implement CPPS, a feedback system is constructed by using the robot operating system (ROS) and an external force estimator which is designed to measure the external force applied to the manipulator without a force sensor. Based on the robot dynamics, the robot-human cooperating system for the cyber physics production system is implemented through a controller that changes the impedance characteristics of the manipulator according to the situation using the external force estimator. Simulation and experimental results verify the effectiveness of the proposed control system.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.31 no.3 s.258
• /
• pp.285-294
• /
• 2007

Previously, ASCI(Automation System for Curtain-wall Installation) which combined with a multi-DOF manipulator to a mini-excavator was developed and applied on construction site. As result, the operation by one operator and more intuitive operation method are proposed to improve ASCI's operation method which need one person with a remote joystick and another operating an excavator. The human-robot cooperative system can cope with various and untypical constructing environment through the real-time interacting with a human, robot and constructing environment simultaneously. The physical power of a robot system helps a human to handle heavy construction materials with relatively scaled-down load. Also, a human can feel and response the force reflected from robot end effecter acting with working environment. This paper presents the feasibility study regarding the application of the proposed human-robot cooperation control for construction robot through experiments on a 2DOF manipulator.