• Journal of the Korean Society for Precision Engineering
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• v.15 no.1
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• pp.26-34
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• 1998

In this paper, a force control algorithm for edge following task is suggested. Through the contact state modeling between rigid part and end-effector of robot, contact force and contact angle that are essencial parameters to build the control strategies for following movement of end-effector are derived. From these two parameters, we discriminate the every contact state into 8 cases and calculate the new moving position and direction simply. For the experiment. RX90 robot from Staubli with robot language V$^{+}$ is applied and F/T sensor is attached to the wrist of robot with RCC. Finally, 3 edge following experiments including the following of corner point are executed with successful results.s.

• The Journal of Korea Robotics Society
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• v.17 no.2
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• pp.164-171
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• 2022

Recently, interest of a dual arm robot which can replace humans is increasing in order to improve the working environment and solve the labor shortage. Various studies related with design and analysis of dual-arm robots have been conducted because dual arm robots can have various kinematic configurations according to the objective task. It is necessary to evaluate the work performance according to various kinematic structures of the dual arm robot to maximize its effectiveness. In the paper, the performance analysis is studied according to the shoulder configuration and the wrist configuration of the dual-arm robot by using main performance indices such as manipulability, condition number, and minimum singular value by assigning proper weight values to each objective motion. Performance analysis for the robotic assembly process is effectively carried out for each representative dual arm robot configuration.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.720-723
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• 1997

This paper presents a cooperative control method for multiple robots. This method is based on local sensors. The proposed method integrates all information obtained by local perception through a set of sensors and generates commands without logical conflicts in designing control logic. To control multiple robots effectively, a global control strategy is proposed. These methods are constructed by using AND/OR logic and transition firing sequences in Petri nets. To evaluate these methods, the object-searching task is introduced. This task is to search an object like a box by two robots and consists of two sub-tasks, i.e., a wall tracking task and a robot tracking task. Simulation results for the object-searching task and the wall tracking task are presented to show the effectiveness of the method.

• International Journal of Precision Engineering and Manufacturing
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• v.6 no.4
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• pp.67-72
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• 2005

In a park or street, we can see many people jogging or walking with their dogs that are chasing their masters. In this study, a pet robot that imitates dog's behavior is developed. The task of robot is to chase a person who is recognized as the master. The physical structure and the sensor system are designed for the task and environment. A three-wheel type locomotion system is designed as the robot's physical structure which can follow a person who is jogging in outdoor environment like a park. A sensor system, which can detect relative position of the master to the robot in highly dynamic and hazardous worlds, is developed. This sensor system consists of a signal transmitter which is held by the master and ultrasonic sensor array which are mounted on the robot. The transmitter emits RF (radio frequency) and ultrasonic signals simultaneously. The ultrasonic sensor array detects the signals and calculates direction and distance between the robot and the transmitter. The developed RF-ultrasonic sensor is evaluated through experiments. A purely reactive behavior-based control architecture is used for the robot. The behavior control performance of the robot is assessed in outdoor and indoor tests.

• Advances in robotics research
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• v.2 no.2
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• pp.113-127
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• 2018

Robotics and automation are rapidly growing in the industries replacing human labor. The idea of robots replacing humans is positively influencing the business thereby increasing its scope of research. This paper discusses the development of an experimental platform controlled by a robotic arm through Robot Operating System (ROS). ROS is an open source platform over an existing operating system providing various types of robots with advanced capabilities from an operating system to low-level control. We aim in this work to control a 7-DOF manipulator arm (Robai Cyton Gamma 300) equipped with an external vision camera system through ROS and demonstrate the task of balancing a ball on a plate-type end effector. In order to perform feedback control of the balancing task, the ball is designed to be tracked using a camera (Sony PlayStation Eye) through a tracking algorithm written in C++ using OpenCV libraries. The joint actuators of the robot are servo motors (Dynamixel) and these motors are directly controlled through a low-level control algorithm. To simplify the control, the system is modeled such that the plate has two-axis linearized motion. The developed system along with the proposed approaches could be used for more complicated tasks requiring more number of joint control as well as for a testbed for students to learn ROS with control theories in robotics.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1109-1114
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• 2003

In this paper, task control architecture is proposed for a mobile robot with behaviors based on cognition theory to endow the robot intelligence. In the task control architecture, task manager is introduced especially for the management of computational resource. The management is based on classical RMS (Rate Monotonic Strategy), but with online rate modulation strategy. The rate modulation is performed using the value variances of behavior execution for the task. Because the values are based on natively uncertain sensor information, they are modeled using PDF (probability Density Function). As a rate modulation process, the range of the rate modulation is defined firstly by real-time constraints of RMS and discrete control stability of behaviors. With the allowable range, rate modulations are performed considering harmonic bases to maintain utilization bound without decrease. To evaluate the efficiency of the proposed rate modulation strategy, a simulation test is performed to compare the efficiency between the control architecture with the proposed strategy and previous one. A performance index with the formalization of propensity of resource allocation is proposed and utilized for the simulation test. To evaluate the appropriateness of the performance index, the performance index is compared with practical one through a practical simulation test.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.814-819
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• 2007

Palletizing task is well-known time consuming and laborious process in factory, hence automation is seriously required. To do this, artificial robot is generally used. These systems however, mostly user teaches the robot point to point and to avoid time-variable obstacle, robot is required to attach the vision camera. These system structures bring about inefficiency and additional cost. In this paper we propose task-oriented trajectory generation algorithm for palletizing. This algorithm based on $A^{*}$ algorithm and slice plane theory, and modify the object dealing method. As a result, we show the elapsed simulation time and compare with old method. This simulation algorithm can be used directly to the off-line palletizing simulator and raise the performance of robot palletizing simulator not using excessive motion area of robot to avoid adjacent components or vision system. Most of all, this algorithm can be used to low-level PC or portable teach pendent

• Journal of KIISE:Software and Applications
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• v.37 no.5
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• pp.370-377
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• 2010

An Intelligent service robot performs various complex tasks in dynamic environment, providing useful intelligent services for human users. The robot needs to continuously monitor dynamically changing environment and reactively choose the best behavior for the changing context. The selected behaviors may include nondeterministic or parallel actions. In this paper, we present a structured reactive robot programming language, SPRIT that is based on Structured Circuit Semantics (SCS). SPRIT is fully implemented as a task executor and tested for reactive robot tasks in dynamic environment to show that it can be used to explicitly represent and effectively implement the complex reactive behaviors of intelligent robot systems.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.244-249
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• 2001

Collision free task planning for dual-arm robot which perform many subtasks in a common work space can be achieved in two steps : path planning and trajectory planning. Path planning finds the order of tasks for each robot to minimize path lengths as well as to avoid collision with static obstacles. A trajectory planning strategy is to let each robot move along its path as fast as possible and delay one robot at its initial position or reduce speed at the middle of its path to avoid collision with the other robot.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.113-118
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• 2000

Collision free task planning for dual-arm robot which perform many subtasks in a common work space can be achieved in two steps : path planning and trajectory planning. Path planning finds the order of tasks for each robot to minimize path lengths as well as to avoid collision with static obstacles. A trajectory planning strategy is to let each robot move along its path as fast as possible and delay one robot at its initial position or reduce speed at the middle of its path to avoid collision with the other robot.