Frequency-Shaped Impedance Control for Safe Human-Robot Interaction in Reference Tracking Application

Sehoon Oh,Hanseung Woo,Kyoungchul Kong 제어로봇시스템학회 2014 제어로봇시스템학회 국제학술대회 논문집 Vol.2014 No.10

In the control of industrial robots, both safety and reference tracking performance are required. For safe human-robot interaction, robots should exhibit low mechanical (or controlled) impedance so that they react to the interaction forces in a compliant manner. On the other hand, the reference tracking requires for the robots to reject exogenous disturbances, which results in an increased impedance. In order to achieve these two conflicting objectives, a frequencyshaped impedance control (FSIC) method is proposed in this paper. The proposed method utilizes the two different functionalities of the disturbance observer (DOB): a disturbance estimation function as an observer and a disturbance rejection function as a feedback controller. Namely, the DOB is utilized as an observer at the frequencies where the robots interact with humans, while it is used as a feedback controller (i.e., disturbance rejection controller) at the frequencies where the reference tracking is required. The proposed approach is realized by shaping a filter of the DOB in the frequency domain so that the impedance is manipulated to achieve both the compliant interaction and reference tracking. The compromised reference tracking performance in the frequency range, where the impedance is set low, can also be supplemented by feedforward control. A typical feedback controller and a feedforward controller are designed in addition to the DOB-controlled system as the whole control system to enhance reference tracking performance and the betterment of stability robustness. The proposed method is verified by experimental results in this paper.

MDPS를 이용한 차량 횡부하 보상

김규원(Kyuwon Kim),이경수(Kyongsu Yi) 한국자동차공학회 2011 한국자동차공학회 학술대회 및 전시회 Vol.2011 No.11

This paper describes lateral disturbance compensation algorithm for an application to a Motor Driven Power Steering (MDPS) based driving assistant system. The lateral disturbance including wind force and load from bank angle reduces the driver refinement and increases the possibility of an accident. In order to reduce the maneuvering effort of the driver in the situation under the lateral disturbance, the lateral disturbance compensation algorithm has been proposed. The lateral disturbance on the vehicle including the lateral force and the yaw moment can be estimated through the previous research, and the lateral disturbance compensation system is based on the estimated lateral disturbance. In order to provide the appropriate assist torque to the driver for compensating the lateral disturbance, the characteristics of the compensation system including a human driver model and the steering system have been mathematically analyzed.

Human-robot collision detection under modeling uncertainty using frequency boundary of manipulator dynamics

정병진,구자춘,최혁렬,문형필 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.11

This paper presents the development and experimental evaluation of a collision detection method for robotic manipulators sharing aworkspace with humans. Fast and robust collision detection is important for guaranteeing safety and preventing false alarms. The maincause of a false alarm is modeling error. We use the characteristic of the maximum frequency boundary of the manipulator's dynamicmodel. The tendency of the frequency boundary’s location in the frequency domain is applied to the collision detection algorithm using aband pass filter (band designed disturbance observer, BdDOB) with changing frequency windows. Thanks to the band pass filter, whichconsiders the frequency boundary of the dynamic model, our collision detection algorithm can extract the collision caused by the disturbancefrom the mixed estimation signal. As a result, the collision was successfully detected under the usage conditions of faulty sensorsand uncertain model data. The experimental result of a collision between a 7-DOF serial manipulator and a human body is reported.

황매산의 관속식물상

김혜원,선은미,이강협,이정심,박범균,최태영,이수랑 한국식물분류학회 2020 식물 분류학회지 Vol.50 No.2

경상남도 합천군과 산청군의 경계에 위치한 황매산(1,108 m)은 소백산맥의 줄기로 식생이 풍부하고 산림생물다양성이 높다. 그러나 지속적인 개발 및 등산객 등 관광객 증가와 함께 외래식물의 유입, 식재로 인한 생태계 교란 등의 문제가 우려되고 있다. 본 연구는 황매산의 관속식물상을 파악하여 현재의 기록을 남 기는 동시에 식물다양성 보존 방안 및 외래식물의 산림 내 추가유입 방지를 위한 기초자료로 활용하고자 계 획되었다. 조사는 2019년 3월부터 동년 10월까지 13회에 걸쳐 계절별로 개화하는 식물을 채집하고, 기록하 는 방식으로 이루어졌다. 조사 결과, 기존 조사에 비해 약 28%의 분류군이 증가한 106과 349속 554종 16아 종 48변종 10품종의 총 628분류군을 확인하였다. 이는 국내 관속식물 4,364분류군의 14.4%에 해당되며, 이 중 양치식물이 26분류군(4.1%), 나자식물이 5분류군(0.8%), 쌍자엽식물이 477분류군(76.0%), 단자엽식물은 120분류군(19.1%)으로 분류되었다. 조사된 분류군 중 특산식물은 16분류군, 산림청지정 희귀식물은 14분류 군이었고, 침입외래식물은 42분류군, 환경부 지정 식물구계학적 등급종은 75분류군으로 나타났다. Hwangmaesan Mt. (1,108 m) is rich in forest biodiversity and is a part of the Sobaek mountain range located in Hapcheon-gun, Gyeongsang-do in Korea. Unfortunately, the biodiversity and ecosystem integrity of Hwangmaesan Mt. have recently been threatened by heavy human disturbances. We conducted thirteen field surveys between March and October of 2019 to investigate the vascular flora in Hwangmaesan Mt. Through this extensive survey, we found 628 taxa consisting of 106 families, 349 genera, 554 species, 16 subspecies, 48 varieties, and 10 forma. Based on a comparative analysis between the present findings and former flora reports, our results showed an increase by 28 percent in the number of taxa observed. Of the 628 taxa, dicotyledons made up the largest group (477 taxa, 76.0%) followed by monocotyledons (120 taxa, 19.1%). Endemic plants consisted of 16 taxa, with rare plants designated by the Korea Forest Service numbering 14 taxa. Ten taxa were listed on the Red list by the Ministry of the Environment. The floristic target species designated by the Ministry of the Environment numbered 75 taxa, whereas there were 42 taxa of invasive plants.

Effects of Human Disturbance on Nesting Little Terns(Sterna albifrons)

Jeong-Eun Lee,Eunyoung Jeong,Seok-Yee Kim,Ha-Cheol Sung 한국조류학회II 2012 한국조류학회지 Vol.19 No.2

Little Terns (Sterna albifrons) lay their eggs on open, sandy beaches where frequent human disturbance could decrease their nesting success. Understanding the effects of human disturbance on breeding birds is important in guiding conservation efforts in and creating management plans for natural areas. We examined the responses of Little Terns to 2 different experimental human activities: human approaches and human existence within the breeding habitats. No differences were observed in both the flight initiation distance of the birds and the length of time spent off the nests between 2 different human approaches, i.e., by 1 person vs. more than 3 people. However, when more than 3 people approached the nests, the nesting birds remained away from the nest for a longer period of time. In addition, the least tolerant distance was significantly greater for the standing observers than for the sitting observers within the breeding habitats. These results suggest that breeding Little Terns are disturbed by human activities and that buffer zones or setback areas (a minimum safe distance of nonintrusion by humans) need to be established to minimize the effects of human disturbance on breeding birds. 쇠제비갈매기(Sterna albifrons)는 넓고 모래 해변에 알을 낳고, 이는 인간의 빈번한 방해가 번식 성공을 감소시킬 수 있다. 번식 조류에 대한 인간 방해 효과를 이해하는 것은 자연 서식지의 관리 계획을 세우고 보호 노력에 대한 가이드 라인을 제공하는 데 중요하다. 우리는 두 가지(인간의 접근과 둥지 서식지 내 인간의 존재) 서로 다른 인간 활동에 대한 쇠제비갈매기의 반응을 조사했다. 인간의 접근 형태(1인과 3인 이상) 사이에 새의 최초 비행 거리와 둥지를 벗어난 시간에 있어서 어떤 차이도 나타나지 않았다. 그러나 3인 이상이 둥지에 접근할 때 포란하고 있는 새는 더 오랜 기간 둥지에 벗어나 있었다. 또한 최소접근허용거리는 번식지 내 앉아있는 관찰자보다 서 있는 관찰자에 대해 의미 있게 더 크게 나왔다. 이런 결과는 번식 중인 쇠제비갈매기가 인간 활동에 의해 방해를 받고 완충 지역과 인간 접근에 대한 최소안전거리를 세워 번식하고 있는 새에 대한 인간 방해를 최소화해야 한다는 것을 제안한다.

도시생태계 내 조류 종풍부도 증진을 위한 인간영향 및 교란가능성의 반영

김윤정 ( Kim Yoon-jung ) 한국환경복원기술학회 2021 한국환경복원기술학회지 Vol.24 No.5

Increase in avian species richness is one of the important issues of urban biodiversity policies, since it can promote diverse ecosystem services such as seed dispersal, education, and pollination. However, though human disturbance can significantly affect avian species richness, there are limited studies on the way to reflect the dynamics of floating population. Therefore, this study analyzed the spatial relationship between avian species richness, floating population, and vegetation cover using telecommunications information to identify the areas that requiring targeted monitoring and restoration action. Bivariate Local Moran’s I was applied to identify LISA cluster map that showing representative biotopes, which reflect significant spatial relationship between species richness and population distribution. Edge density and distribution of ndvi were identified for evaluating relative adequacy of selected biotopes to strengthen the robust biodiversity network. This study offers insight to consider human disturbance in spatial context using innovative big data to increase the effectiveness of urban biodiversity measures.

불암산에 번식하는 박새류(Parus spp.)의 인공둥지 이용 유형 분석

조현우(Hyun Woo Jo),이후승(Who-Seung Lee),정훈(Hoon Chung) 한국조류학회 2021 한국조류학회지 Vol.28 No.2

본 연구는 불암산에 설치된 인공새집에서 번식하는 박새류(Parus spp.)를 대상으로 2017년 3월부터 2020년 7월까지 진행되었다. 각 인공새집에서 가장 인접한 인간간섭요소까지의 최단거리(Nearest distance between artificial bird nests and human disturbance factors; NDNH)에 따른 박새류의 인공새집 이용 유형을 분석하기 위해서 첫 번째, 번식상태에 대한 평가를 지수화로 계산한 둥지점수와 4년 동안 NDNH의 관계를 비교하였다. 두 번째, 4년 동안 NDNH에 따른 인공새집 이용률을 비교하였다. 세 번째, NDNH와 최초산란일 간의 관계를 비교하였다. 마지막으로, 번식수행의 시계열적 변화를 분석하기 위해서 모든 NDNH의 중간값을 기준으로 나눈 두 그룹(인간간섭요소와 가까운 그룹과 먼 그룹), 연도, 인공새집의 번식 성공 여부와 박새류가 이용한 인공새집 개수 간의 관계를 살펴보았다. 분석 결과, NDNH가 길수록 둥지점수의 합이 낮았고, 인공새집 이용률이 낮았으며, 각 인공새집별 최초산란일이 느려졌다. 또한, 연도별 번식에 성공한 인공새집 개수는 증가하였고, 번식에 성공하지 못한 인공새집 개수는 감소하였으며 서로 유의한 차이가 나타났다. 인간간섭요소와 가까운 그룹에서 연도별로 인공새집 이용 개수의 변화는 거의 없는 반면, 인간간섭요소와 먼 그룹에서는 연도별로 인공새집 이용 개수가 증가하였다. 본 연구에서 분석된 박새류의 경우, 번식에 유리한 지역의 인공새집을 먼저 차지하고, 상대적으로 덜 유리한 지역이 나중에 채워짐을 확인하였고, 둥지 장소 선택의 유형이 서식지 선택 이론(habitat selection theory)에 부합됨을 고찰하였다. 본 연구 결과는 산림의 산책로와 숲 놀이터 같은 인간간섭요소가 번식기 박새류의 둥지 장소 선택에 영향을 미치는지 여부를 판단하기 위한 기초자료로 활용될 수 있다. To understand the nesting site availability of tits (Parus spp.) in Mount Buram, Korea, we collected field data using artificial bird nests during the breeding season of 2017-2020. Specifically, we analyzed the effects of the nearest distance between the artificial bird nests and human disturbance factors (i.e., NDNH) on breeding performance, such as the scored nest stage and laying date of first egg. NDNH was significantly correlated with the scored nest stage: the shorter the NDNH, the better breeding performance and the higher the nesting site availability. In particular, the laying date of the first egg was negatively correlated with NDNH: the shorter the NDNH, the earlier the egg laying date of first egg. At a greater NDNH, the availability of nest boxes significantly increased annually, whereas at a shorter NDNH, the availability of nest boxes was comparable. Our findings support the habitat selection theory, which states that good habitats are occupied earlier, whereas poor habitats are occupied later. Habitats closer to human disturbance may help avoid predation; thus, tits inhabiting mountains in towns may prefer as nesting sites. However, additional field studies are warranted to validate this speculation.

Performance Comparison of Position Controlled Robotic Stage When Force- and Position-Based Disturbance Observers are Implemented

Kangwagye Samuel,Junyoung Kim,Sehoon Oh 제어로봇시스템학회 2021 제어로봇시스템학회 국제학술대회 논문집 Vol.2021 No.10

Position control of the robotic stage when position-based and force-based disturbance observers (DOB) are implemented and their performances compared is presented in this paper. Implementation of the DOBs is aimed at improving the quality of force control by suppressing the disturbances within and into the robot mechanical system. This is because the accuracy of position control is of paramount importance since bad position control affects the reproducibility of the position perturbation which in-turn affects the production of reliable force readings for balance assessment function with the robotic stage. The overall control and disturbance suppression performance is analyzed and compared for all the control strategies. Simulations and experiments are conducted to evaluate the position control strategies. Moreover, the obtained reaction force recorded when the DOB-based position control strategies are utilized is also analyzed to point out their differences which are caused by the designed controllers.

장기 카메라트래핑 모니터링 자료를 활용한 도시근교의 고라니 및 멧돼지 일주기성 연구

한윤하,신원협,김지환,김도희,윤지원,이석영,김용환,이승현,송영근 한국환경복원기술학회 2024 한국환경복원기술학회지 Vol.27 No.2

This study aimed to figure out diel activity patterns of water deer and wild boar, whose habitat is disturbed by human activity in a suburban area. Photographic data of water deer and wild boar collected by 18 camera traps from January 2021 to November 2022 was categorized into four diel periods (dawn, day, dusk, and night), and converted into frequencies per 100 CTD (Camera Trap-Days) for seasonal and spatial diel activity pattern analysis. Water deer exhibited intense nocturnality in fall, and wild boar did in fall and winter. During the fall, water deer's night-time capture rate was the highest (61.9%), and day-time photographic rate was the lowest (13.9%) among other seasons. During the fall and winter, wild boar's night-time photographic rate was relatively high (77.6%, 78.0%, respectively), and day-time photographic rate was relatively low (0.7%, 1.8%) in comparison with other seasons. In spatial diel activity analysis, both water deer and wild boar showed a tendency to avoid humans, especially near trails during day-time hours. The day-time photographic rate of water deer in trail-near group was 12.1% and trail-far group was 24.6%. The day-time photographic rate of wild boar was 3.4%, 5.7%, respectively. Because the diel activity patterns of wildlife reflect human disturbance, this study provides useful ecological information for developing appropriate management plans for the coexistence of water deer and wild boar in suburban areas.

Variation of forest stands characteristics along elevational gradient in Popa Mountain Park, Central Myanmar

( Naw M L Thant ),( Jasson R M John ),( Woo Shin Lee ),( Victor Kteplyakov ),( Zar Chi Hlaing ) 한국임학회 2012 한국임학회 학술발표논문집 Vol.2012 No.-

Species composition, diversity and stand structure generally vary along elevational gradient, although this may differ from one region to another depending on aspects and physical characteristics on a particular mountain. Understanding these variations may be essential in design of conservation strategies, for example, restoration. Between July and August 2010, we carried out vegetation study in Popa Mountain Park to investigate the variation of forest stand characteristics along elevational gradient. We established a total of 46 vegetation sample plots (30 x 30 m) at three elevation ranges (low; 301-600 m, mid; 601-900 m and high; > 900 m). A total of 93 tree species of 41 families were recorded. Overall tree density varied from 220 to 517 trees ha-1and basal area, consequently, from 5.0 to 20.8m2 ha-1. The higher the elevation, the higher tree density and basal area, whereas the highest species diversity and richness were observed in mid elevation stands. Sapling and seedling densities were recorded low in high elevation. Mid and low elevation were more similar in terms of species composition (62 %) while high and low elevation had the lowest similarity (19 %). Stand structures of all elevation ranges showed reverse J -shaped curves indicating that the stands had a growing and healthy population structure. Only few species were dominant in the high elevation stands in comparison to other elevation stands. Apart from topographic influences and varying microclimates along the elevation, there is little doubt that human disturbance is also influencing forest stand characteristics in Popa Mountain Park.