• International Journal of Fuzzy Logic and Intelligent Systems
• /
• v.3 no.2
• /
• pp.244-250
• /
• 2003

In this paper, the relationship between a slave robot and the uncertain remote environment is modeled as the impedance to generate the virtual force to feed back to the operator. For the control of a tele-operated mobile robot equipped with camera, the tele-operated mobile robot take pictures of remote environment and sends the visual information back to the operator over the Internet. Because of the limitation of communication bandwidth and narrow view-angles of camera, it is not possible to watch the environment clearly, especially shadow and curved areas. To overcome this problem, the virtual force is generated according to both the distance between the obstacle and robot and the approaching velocity of the obstacle. This virtual force is transferred back to the master over the Internet and the master(two degrees of freedom joystick), which can generate force, enables a human operator to estimate the position of obstacle in the remote environment. By holding this master, in spite of limited visual information, the operator can feel the spatial sense against the remote environment. This force reflection improves the performance of a tele-operated mobile robot significantly.

• Journal of Institute of Control, Robotics and Systems
• /
• v.9 no.8
• /
• pp.585-591
• /
• 2003

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.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.19 no.5
• /
• pp.259-265
• /
• 2024

In this paper, we propose an automatic display defect detection system using image processing. The existing inspection by operators has the disadvantage that human errors may occur due to the operator's skill level, fatigue, etc., and that standardization and quantification are difficult. It also has disadvantages such as the limited inspection speed and the cost of the operator's education. The proposed system automatically detects various display defects through image processing algorithms. It was developed based on the Jetson Nano, one of the most popular SBCs (Single Board Computers), and it has a conveyor belt to automatically moves the display to the inspection position. By providing a human machine interface (HMI), the operator can check the inspection information in real time, and control the inspection flow. By storing the inspection results as a log file, the operator can check the inspection results at any time, such as the time taken to perform each algorithm and the location of the detected defects. In addition, a multi-threaded structure was adopted. The camera's operations and inspection algorithms are executed in parallel in different threads, which can shorten the inspection time compared to the system based on a single-threaded structure. The experimental results prove the defect detection capability of the system and the efficiency of the inspection time.

• Journal of Korean Institute of Industrial Engineers
• /
• v.26 no.2
• /
• pp.88-94
• /
• 2000

For efficient operation, vital hand controls must be easily controlled by the operator from his or her normal working position. The primary working area based on the operator-perceived working comfort was developed to serve as a design guideline to the control panel layout. Six male and four female subjects voluntarily participated in the experiment in which working comfort was measured for two types of controls - knob and lever. The operator-perceived working comfort was examined for the frontal and sagittal distances from the body center and the slope of a work surface. The response surface methodology using a central composite design was employed to develop a prediction model for operator's working comfort on each type of controls. The proposed working areas based on the actual working comfort of an operator avoided the dichotomy that considers only the reachability of control devices, and showed a distinct shape, when compared to the existing normal working areas following the Farley's concept. It was shown that the distance from the body to control devices and the slope of a work surface have a quadratic relationship to the working comfort, and that the most comfortable area for seated tasks is located at the distance of about 2∼4 cm in the sagittal direction and about 42∼43 cm in the frontal direction from the shoulder, respectively. It was also found that the working comfort varies within the working area even at the positions with an equal distance from the body. It is expected that the isocomfort working area generated in the study will be used as a useful guideline for control panel layout.

• Transactions on Control, Automation and Systems Engineering
• /
• v.4 no.1
• /
• pp.32-37
• /
• 2002

Applications of scaled telemanipulation into micro or nano world that shows many different features from directly human interfaced tools have been increased continuously. Here, we have to consider many aspects of scaling such as force, position, and impedance. For instance, what will be the possible range of force and position scaling with a specific level of performance and stability\ulcorner This knowledge of feasible staling region can be critical to human operator safety. In this paper, we show the upper bound of the product of force and position scaling and simulation results of 1DOF scaled system by using the Llewellyn's unconditional stability in continuous and discrete domain showing the effect of sampling rate.

• Journal of Biosystems Engineering
• /
• v.33 no.3
• /
• pp.196-203
• /
• 2008

Hybrid robust image processing algorithm to extract visual features of melon during the cultivation was developed based on a wireless tele-operative interface. Features of a melon such as size and shape including position were crucial to successful task automation and future development of cultivation data base. An algorithm was developed based on the concept of hybrid decision-making which shares a task between the computer and the operator utilizing man-computer interactive interface. A hybrid decision-making system was composed of three modules such as wireless image transmission, task specification and identification, and man-computer interface modules. Computing burden and the instability of the image processing results caused by the variation of illumination and the complexity of the environment caused by the irregular stem and shapes of leaves and shades were overcome using the proposed algorithm. With utilizing operator's teaching via LCD touch screen of the display monitor, the complexity and instability of the melon identification process has been avoided. Hough transform was modified for the image obtained from the locally specified window to extract the geometric shape and position of the melon. It took less than 200 milliseconds processing time.

• Journal of Institute of Control, Robotics and Systems
• /
• v.3 no.6
• /
• pp.639-643
• /
• 1997

This paper presents how nonlinear PID control algorithms can be applied on chemical processes for a more stable operation and perfect automation. A pass balance controller is designed to balance the exiting temperatures of a heater and a heat exchange network. The proposed controller has gain-varying integral action and deals with the operational constraints in an efficient manner. Also, the use of a PID gap controller is proposed to maximize energy saving and operation stability and to minimize operator intervention in operation of air fan coolers. The proposed controller adjusts the opening of a louver automatically in such a way that it keeps the air fan pitch position within the desired range. All these nonlinear PID controllers have been implemented on the distributed control system (DCS) for good reliability and operability. Operator acceptance was very high and the implemented controllers have shown good performance and high service factor still now on. The proposed methodology can be directly applied to similar processes without any modification.

• Journal of Biosystems Engineering
• /
• v.29 no.1
• /
• pp.71-78
• /
• 2004

Real time and robust algorithm to extract the features of watermelon was developed from the remotely transmitted image of the watermelon. Features of the watermelon at the cultivation site such as size and shape including position are crucial to the successful tole-robotic operation and development of the cultivation data base. Algorithm was developed based on the concept of task sharing between the computer and the operator utilizing man-computer interface. Task sharing was performed based on the functional characteristics of human and computer. Identifying watermelon from the image transmitted from the cultivation site is very difficult because of the variable light condition and the complex image contents such as soil, mulching vinyl, straws on the ground, irregular leaves and stems. Utilizing operator's teaching through the touch screen mounted on the image monitor, the complex time consuming image processing process and instability of processing results in the watermelon identification has been avoided. Color and brightness characteristics were analyzed from the image area specified by the operator's teaching. Watermelon segmentation was performed using the brightness and color distribution of the specified imae processing area. Modified general Hough transform was developed to extract the shape, major and minor axes, and the position, of the watermelon. It took less than 100 msec of the image processing time, and was a lot faster than conventional approach. The proposed method showed the robustness and practicability in identifying watermelon from the wireless transmitted color image of the cultivation site.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.19 no.6
• /
• pp.35-40
• /
• 2019

In this research, we suggest a real-time tele-driving system for unmanned drone operations using the LTE communication system. The drone operator is located 180km away and controls the altitude and position of the drone with a 50ms time delay. The motion data and video from the drone is streamed to the operator. The video is played on the operator's head-mounted display (HMD) and the motion data emulates the drone on the simulator for the operator. In general, a drone is operated using RF signal and the maximum distance for direct control is limited to 2km. For long range drone control over 2km, an auto flying mode is enabled using a mission plan along with GPS data. In an emergency situation, the autopilot is stopped and the "return home" function is executed. In this research, the immersion tele-driving system is suggested for drone operation with a 50ms time delay using LTE communication. A successful test run of the suggested tele-driving system has already been performed between an operator in Daejeon and a drone in Inje (Gangwon-Do) which is approximately 180km apart.

• Journal of Institute of Control, Robotics and Systems
• /
• v.19 no.4
• /
• pp.315-321
• /
• 2013

This paper presents the position-based force control application of a mobile manipulator. The mobile manipulator consists of two six DOF manipulators and a mobile robot. Kinematics of the robot is analyzed and simulated to validate the analysis. A position-based force control technique is applied to the robot by adding an outer loop to interact with the environment. Experimental studies of force control applications of robot arm and interaction with a human operator are conducted. Experimental results show that the robot arm is well regulated to follow the desired force.