• Journal of Institute of Control, Robotics and Systems
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• v.19 no.3
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• pp.233-239
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• 2013

This paper presents the analysis and control of the position of the COG (Center of Gravity) for a two-wheel balancing robot. The two-wheel balancing robot is required to maintain balance by driving two wheels only. Since the robot is not exactly symmetrical and its dynamics is changing with respect to moving parts, robust balancing control is difficult. Balancing performance becomes difficult when two arms hold a heavy object since the center of gravity is shifted out of the wheel axis. Novel design of a sliding waist mechanism allows the robot to react against the shift of the COG by moving the whole upper body to compensate for the imbalance of the mass as a counter balancer. To relocate the COG position accurately, the COG is analyzed by force data measured from two force sensors. Then the sliding COG mechanism is utilized to control the sliding waist position. Experimental studies are conducted to confirm the proposed design and method.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.5
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• pp.537-542
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• 2014

This paper proposes a control system to keep the balance of a unicycle robot. The robot consists of the disk and wheel, for balancing and driving respectively, and the tile angle is measured and used for balancing by the IMU sensor. A PID controller is designed based on a non-model based algorithm to prove that it is possible to control the unicycle robot without any approximated linear system model such as the sliding mode control algorithm. The PID controller has the advantage that it is simple to design the controller and it does not require an unnecessary complex formula. In this paper, assuming that the pitch and roll axis are dynamically decoupled, each of the two controllers are designed separately. A reaction wheel pendulum method is used for the control of the roll axis, that is, for balancing and an inverted pendulum concept is used for the control of the pitch axis. To confirm the performance of the proposed controllers using MATLAB Simulink, the dynamic equations of the robot are derived.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.3
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• pp.315-322
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• 2009

This paper explains a control and navigation algorithm of a 6-DOF gait rehabilitation robot, which can allow a patient to navigate in virtual reality (VR) by upper and lower limbs interactions. In gait rehabilitation robots, one of the important concerns is not only to follow the robot motions passively, but also to allow the patient to walk by his/her intention. Thus, this robot allows automatic walking velocity update by estimating interaction torques between the human and the upper limb device, and synchronizing the upper limb device to the lower limb device. In addition, the upper limb device acts as a user-friendly input device for navigating in virtual reality. By pushing the switches located at the right and left handles of the upper limb device, a patient is able to do turning motions during navigation in virtual reality. Through experimental results of a healthy subject, we showed that rehabilitation training can be more effectively combined to virtual environments with upper and lower limb connections. The suggested navigation scheme for gait rehabilitation robot will allow various and effective rehabilitation training modes.

• Journal of the Korean Institute of Intelligent Systems
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• v.12 no.4
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• pp.379-384
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• 2002

This paper represents the mobile robot system remote controlled by PDA(personal digital assistance). So far, owing to the development of internet technologies, lots of remote control methods through internet have been proposed. To control a mobile robot through internet and guide it under unknown environment, We propose a control method activated by PDA. In a proposed system, PDA acts as a user interface to communicate with notebook as a controller of the mobile robot system using TCP/IP protocol, and the notebook controls the mobile robot system. The information about the direction and velocity of the mobile robot feedbacks to the PDA and the PDA send new control method produced from the fuzzy inference engine.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.6
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• pp.470-476
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• 2001

This paper presents a new algorithm of path planning and obstacle avoidance for autonomous mobile robots with vision system that is working in unknown environments. Distance variation technique is used in path planning to approach the target and avoid obstacles in work space as well . In this approach, the Sobel operator is employed to detect edges of obstacles and the distances between the mobile robot and the obstacles are measured. Fuzzy rules are used for trajectory planning and obstacle avoidance to improve the autonomy of mobile robots. It is shown by computer simulation that the proposed algorithm is superior to the vector field approach which sometimes traps the mobile robot into some local obstacles. An autonomous mobile robot with single vision is developed for experiments. We also show that the developed mobile robot with the proposed algorithm is navigating very well in complex unknown environments.

• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.3
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• pp.223-228
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• 2015

This paper analyses the torque characteristics of the shoulder and elbow joints of a humanoid robot arm that is useful for an object lifting and transferring task instead of human beings. For the purpose, some typical human lifting behaviors are considered, and various simulations for lifting and transferring an object have been performed by employing a humanoid robot arm having a simple configuration of shoulder and elbow joints. Through the simulation, it is shown that the torque patterns and ranges of the shoulder and elbow joints required for such a humanoid lifting and transferring task can be found earlier in the design of a humanoid robot arm. As a result, this effort is useful for us to design an effective robot arm.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.4
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• pp.412-417
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• 2014

This paper presents the development and control of an omni-directional holonomic mobile robot platform, which is equipped with three lateral orthogonal-wheel assemblies. Omni-directionality can be achieved with decoupled rotational and translational motions. Simulation studies on collision avoidance are conducted. A real robot is built and its hardware is implemented to control the robot. Control algorithm is embedded on DSP and FPGA chips. Hardware for motor control such as PWM, encoder counter, serial communication modules is implemented on an FPGA chip. Experimental studies of following joystick commands are performed to demonstrate the functionality and controllability of the robot.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.11
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• pp.904-911
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• 2001

A broomstick swinging biped acrobatic controller is designed and simulated to show capability of the system of controllers: virtual model controller is employed for the robot\`s posture balancing control while a higher level fuzzy controller modulate the one of the virtual model controller\`s parameter for the pendulum swinging motion generation. The robot is of 7 degree-of-freedom, 8-link planar bipedal robot having two slim legs and a body. Each leg consists of a hip joint, a knee joint, an ankle joint and the body has a free joint at the top in the head at which a freely rotating broomstick is attached. We assume that the goal for the acrobat robot is to maintain a body balance in the sagittal plane while swinging up the freely up the freely rotating pendulum. We also assume that the actuators in the joints are all ideal torque generators. The proposed system of controllers satisfies the goal and the simulation results are presented.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.9
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• pp.758-765
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• 2001

This paper proposes a method to automatically extract stable visual landmarks from sensory data. Given a 2D occupancy map, a mobile robot first extracts vertical line features which are distinct and on vertical planar surfaces, because they are expected to be observed reliably from various viewpoints. Since the feature information such as position and length includes uncertainty due to errors of vision and motion, the robot then reduces the uncertainty by matching the planar surface containing the features to the map. As a result, the robot obtains modeled stable visual landmarks from extracted features. This extraction process is performed on-line to adapt to an actual changes of lighting and scene depending on the robot’s view. Experimental results in various real scenes show the validity of the proposed method.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.610-615
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• 2005

Visual servoing is the fusion of results from many elemental areas including high-speed image processing, kinematics, dynamics, control theory, and real-time computing. It has much in common with research into active vision and structure from motion, but is quite different from the often described use of vision in hierarchical task-level robot control systems. We present a new approach to visual feedback control using image-based visual servoing with the stereo vision in this paper. In order to control the position and orientation of a robot with respect to an object, a new technique is proposed using a binocular stereo vision. The stereo vision enables us to calculate an exact image Jacobian not only at around a desired location but also at the other locations. The suggested technique can guide a robot manipulator to the desired location without giving such priori knowledge as the relative distance to the desired location or the model of an object even if the initial positioning error is large. This paper describes a model of stereo vision and how to generate feedback commands. The performance of the proposed visual servoing system is illustrated by the simulation and experimental results and compared with the case of conventional method for dual-arm robot made in Samsung Electronics Co., Ltd.