Soon-Yong Yang

Design and experimental evaluation of a robust force controller for a 6-link electro-hydraulic manipulator via h∞ control theory

Uninterrupted power supply has become indispensable during the maintenance task of active electric power lines as a result of today’s highly information-oriented society and increasing demand of electric utilities. This maintenance task has the risk of electric shock and the danger of falling from high place. Therefore it is necessary to realize an autonomous robot system using electro-hydraulic manipulators because hydraulic manipulators have the advantage of electric insulation and power/mass density. Meanwhile an electro-hydraulic manipulator using hydraulic actuators has many nonlinear elements, and its parameter fluctuations are greater than those of an electrically driven manipulator. So it is relatively difficult to realize not only stable contact work but also accurate force control for the autonomous assembly tasks using hydraulic manipulators. In this paper, the robust force control of a 6-link electro-hydraulic manipulator system used in the real maintenance task of active electric lines is examined in detail. A nominal model for the system is obtained from experimental frequency responses of the system, and the deviation of the manipulator system from the nominal model is derived by a multiplicative uncertainty. Robust disturbance observers for force control are designed using this information in an H∞ framework, and implemented on the two different setups. Experimental results show that highly robust force tracking by a 6-link electro-hydraulic manipulator could be achieved even if the stiffness of environment and the shape of wall change.

A study on the development of multi-stage solenoid valve

Solenoid valves are the basic element part that widely used in various industries. According to the performance requirements of the market, it is available in a wide range of shapes and size. In this paper, a large flow multi-stage solenoid valve has been designed and developed by configuring the orifice, diaphragm and solenoid. At first each part has modeled and by combining them a virtual multi-stage solenoid valve has developed and finally the following results have derived from the simulation results of the developed model.

The energy stability margin for tracked vehicle mounted manipulator

The stability margin for Tracked Vehicle that are sufficient conditions for safe. The stability margin bases on energy stability level at each edge of support boundary. Similarly, this concept takes into consideration the instantaneous change of machines center of gravity position while the manipulator swings with a constant velocity. Moreover, inertial and manipulation effects usually appear in the motion of such vehicles when that are used for services or industrial applications. The stability margin mentions the minimum of dynamic energy level changing follow boundary edge during motion is proposed without turning over. In this paper, the stability of vehicle is investigated as the reflection of the interact energy. If this energy level is over the margin, it will make projection of center of gravity to be out of the support boundary, the machine will be turned over. This paper presents a type of survey to analysis the safe margin of this machine in various situations.

Study on development of easy operating system for field robot in virtual reality environment

Hydraulic excavators are among the most versatile earthmoving equipment: these machines are used in civil engineering, hydraulic engineering, grading and landscaping, pipeline construction and mining. Especially, in flattening task, the excavator operator actuates the machine controls (joysticks, pedals and switches) in an organized form to achieve the desired straight motion. The actuation of these controls is a complex and not intuitive task, and therefore it requires long and costly training periods. Applying automation in these types of field robot is studied by several researchers. This paper proposes an easy operating system for field robot. This design lets each joystick perform independent horizontal and vertical motions of the end of bucket. The proposed method allows an user to control the excavator intuitively and operate complex motions smoothly with no constraints. For this, a virtual excavator scheme with a joystick control has been developed. Besides, the virtual reality interface is designed to allow the user be able to observe the motion of the attachment.

H∞ control system for tandem cold mills with roll eccentricity

In order to meet the requirement for higher thickness accuracy in cold rolling processes, it is strongly desired to have high performance in control units. To meet this requirement, we have considered an output regulating control system with a roll-eccentricity estimator for each rolling stand of tandem cold mills. Considering entry thickness variation as well as roll eccentricity as the major disturbances, a synthesis of multivariable control systems is presented based onH∞ control theory, which can reflect the knowledge of input direction and spectrum of disturbance signals on the design. Then, to reject roll eccentricity effectively, a weight function having some poles on the imaginary axis is introduced. This leads to a non-standardH∞ control problem, and the design procedures for solving this problem are analytically presented. The effectiveness of the proposed control method is evaluated through computer simulations and compared to that of the conventional LQ control and feedforward control methods for roll eccentricity.

A Study on Remote Control System Integrated Intuitive Vision System for Field Robot Using Head Tracker system

Operating excavator on the risk surroundings is not safe for human to control on site. Consequently, automatic excavator called Field Robot has been researched to protect the workers from the hazardous environments. The remote excavation system is required to perform in such environments. This paper presents the study on remote control system for the Field Robot and intuitive vision system for user via head tracker system. The design of the remote control system consists Remote Station and Filed Robot. In Remote Station, user can send the control commands through wireless communication. Besides, the IMU sensor is integrated in head mounted display (HMD) to measure the motion of humans head. These signals are transferred to the pan/tilt motor controller and operate the motion of the CCD camera following the movement of operators head. The Field Robot is also contributed and some experiments are carried out to prove the feasibility of the proposed system.

Automatic assembly task of electric line using 6-link electro-hydraulic manipulators

Uninterrupted power supply has become indispensable during the maintenance task of active electric power lines as a result of today’s highly information-oriented society and increasing demand of electric utilities. The maintenance task has the risk of electric shock and the danger of falling from high place. Therefore it is necessary to realize an autonomous robot system using electro-hydraulic manipulator because hydraulic manipulators have the advantage of electric insulation. Meanwhile it is relatively difficult to realize autonomous assembly tasks particularly in the case of manipulating flexible objects such as electric lines. In this report, a discrete event control system is introduced for automatic assembly task of electric lines into sleeves as one of the typical task of active electric power lines. In the implementation of a discrete event control system, LVQNN (linear vector quantization neural network) is applied to the insertion task of electric lines to sleeves. In order to apply these proposed control system to the unknown environment, virtual learning data for LVQNN is generated by fuzzy inference. By the experimental results of two types of electric lines and sleeves, these proposed discrete event control and neural network learning algorithm are confirmed very effective to the insertion tasks of electric lines to sleeves as a typical task of active electric power maintenance tasks.

Development of the flexible observation system for a virtual reality excavator using the head tracking system

Operating excavator on the risk surroundings is not safe for human to control on site. Consequently, automatic excavator called Field Robot has been researched to protect the workers from the hazardous environments. The remote excavation system is required to perform in such environments. This paper presents the study on remote control system for the Field Robot and augmented reality vision for user using head tracker system. The design of the remote control system that consist Remote Station and Filed Robot. In Remote Station, user can send the control commands through wireless communication. Besides, the Inertial Measurement Unit (IMU) sensor is integrated in a head mounted display (HMD) to track the motion of humans head. These signals are transferred to the pan/tilt motor controller and to operate the motion of the CCD camera following the movement of operators head. The Field Robot is also contributed and some experiments are carried out to prove the feasibility of the proposed system.

A study of stability for field robot using energy stability method

In this paper, the energy stability level concept is used for examining the stable state of field robot under effects of swing motion, at some particular postures of manipulator and terrain conditions. The energy stability level is calculated by using the dynamic models of field robot, subject to the concept of equilibrium plane and support boundary. The results are simulated by using Matlab/Simulink for estimating the stability of field robot to supply useful predictions of stability analysis to designers and operators..

Development Platform for the three-wheeled electric vehicle Unmanned

This paper describes a production process of unmanned 3-wheel vehicle. We selected EVs components and specification for the manufacturing of electric vehicles. and We made electric vehicle directly. Typical feature of our EV is method of motor drive. One motor is installed to rear wheel. we need to control at rear wheels. we measured steering angle, motor rpm. and We made program that control wheel operation dependent on vehicle speed and steering angle.