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Disturbance Observer-Based Force Control of Hydraulic Actuator
Jangho Bae(배장호) 한국기계가공학회 2024 한국기계가공학회지 Vol.23 No.2
A disturbance observer-based force control method was proposed for a hydraulic actuator to enhance force tracking performance. Through an analysis of the linearized force dynamics based on the physical model of the hydraulic actuator, it was confirmed that the bandwidth of the system was constrained by the effect of load dynamics, known as natural velocity feedback. The proposed method incorporates a disturbance observer and a linear load dynamics compensator designed to eliminate the effect of the load dynamics on the force dynamics of the hydraulic actuator. The proposed force controller for the hydraulic actuator was experimentally validated using a single-degree-of-freedom experimental setup. The proposed force controller for the hydraulic actuator provides high performance in hydraulic parameter uncertainty. Another advantage of this approach is that additional sensors are not required for the measurement of state information such as pressure.
Cooperative Underwater Vehicle-Manipulator Operation Using Redundant Resolution Method
Jangho Bae,Yecheol Moon,Eugene Park,Jongwon Kim,Sangrok Jin,TaeWon Seo 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.23 No.9
This paper presents a cooperative manipulation method for a dual-arm underwater vehicle-manipulator system (UVMS). The objective task is handle valve turning, which is a common underwater task. We propose a manipulation method that includes the concept of grasping a fixed structure such as a pipeline. While grasping a fixed structure and a handle valve, the entire system can be considered a parallel manipulator. Because of the kinematic properties of the system, the load for turning the handle valve can be distributed between the vehicle and the dual-arm manipulator, which means the vehicle can help with the operation of the manipulator. In addition, external disturbances such as oceanic currents can be efficiently compensated by using the proposed cooperative method due to the properties of the system. The kinematics and dynamics of the system were analyzed. The cooperative manipulation method was developed by modifying and adjusting redundancy resolution method with theory of a parallel manipulator. To prove the superiority of the method, a dual-arm UVMS was designed and fabricated. The advantages of the proposed cooperative method were validated through simulations and experiments.
Bae, Jangho,Bak, Jeongae,Jin, Sangrok,Seo, TaeWon,Kim, Jongwon Elsevier 2018 Mechanism and machine theory Vol.123 No.-
<P><B>Abstract</B></P> <P>An underwater vehicle manipulator system (UVMS) has several applications including mining, exploring, and building underwater structures. The current study presents a method to design and optimize an UVMS configuration by measuring the performance of various design alternatives. The concept of a dual-arm manipulator was proposed, and a design alternative was developed for the dual-arm manipulator. Additionally, modified dynamic manipulability that considers hydrodynamic effects was selected to measure the performance of design alternatives. Each alternative was optimized by using a genetic algorithm to maximize dynamic manipulability through a desired task. Optimized alternatives were compared, and the optimal design of a dual-arm manipulator was selected from the alternatives. The proposed method considered hydrodynamic effects on an UVMS to design and optimize a dual-arm UVMS.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Underwater vehicle manipulator system configuration and parameters are optimized. </LI> <LI> Four design alternatives are determined based on degrees of freedom constraints. </LI> <LI> New dynamic manipulability for underwater is defined. </LI> <LI> Configuration and parameters are optimized on the optimized trajectory. </LI> <LI> Torque limit of actuators is considered to discuss the results. </LI> </UL> </P>
Automatic Identification of Excavator Activities Using Joystick Signals
Jangho Bae,김기영,홍대희 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.12
Monitoring and analyzing the operations of construction equipment is critical in the construction engineering and management domain. The ability to detect and classify major activities that construction equipment performs can support a project manager in making proper project-related decisions such as resource allocation and scheduling, resulting in improved productivity. Earth-moving activities as performed by an excavator, which is one of the most frequently used pieces of construction equipment, are normally repetitive by nature and possess unique features in terms of their patterns of operation. This study develops an activity identification algorithm capable of automatically classifying predefined earth-moving activities that are currently in progress. Given that the excavator is operated using joysticks, the joystick signals include unique patterns that exhibit the similar overall shapes but may not uniformly line up with time for a specific activity. The proposed study examines a dynamic time warping algorithm that determines similarities between a predefined activity and a measured signal distorted in time. The feasibility of the algorithm is verified through experiments involving activities such as digging, leveling, lifting, and trenching that were easily and accurately identified by the algorithm. The proposed task-identification algorithm could be used to develop an automated system of establishing machine parameters and to calculate the durations of operations and cycle times.
Improved determination ofBKwith staggered quarks
Bae, Taegil,Jang, Yong-Chull,Jeong, Hwancheol,Jung, Chulwoo,Kim, Hyung-Jin,Kim, Jangho,Kim, Jongjeong,Kim, Kwangwoo,Kim, Sunghee,Lee, Weonjong,Leem, Jaehoon,Pak, Jeonghwan,Park, Sungwoo,Sharpe, Stephe American Physical Society 2014 PHYSICAL REVIEW D - Vol.89 No.7