Development of bulldozer sensor system for estimating the position of blade cutting edge

Kim, Sang-Ho,Lee, Yong-Seok,Sun, Dong-Ik,Lee, Sang-Keun,Yu, Bo-Hyun,Jang, Sung-Hoon,Kim, Wansoo,Han, Chang-Soo Elsevier 2019 AUTOMATION IN CONSTRUCTION - Vol.106 No.-

<P><B>Abstract</B></P> <P>This paper proposed a bulldozer sensor system for estimating the blade cutting edge position, designed to help bulldozer operators guide the bulldozer blade cutting edge towards a precise position in leveling works. The proposed sensor system consists of two GNSSs, two IMUs, and a position estimation controller. Each sensor and position estimation controller are connected through CAN and RS-232 communications, which facilitate reception of the GNSS's position data and the IMU's angle data as well as the calculation of the bulldozer posture and the blade position. A blade cutting edge position estimation formula is proposed using the frame mapping method reflecting kinematic analysis to calculate the position of the blades. The bulldozer mechanism was modeled, and the effectiveness of the proposed method was verified via simulation to determine accuracy of the estimated positions. The proposed sensor system was then applied to a navigation system to estimate the position of the blade cutting edge after being mounted on an actual bulldozer. The performance of the proposed sensor system was verified by comparing with the positions provided by a commercial GPS.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We proposed a sensor system for estimating a bulldozer's blade cutting edge position. </LI> <LI> The sensor system is composed to dual RTK GPS sensor and two motion sensors. </LI> <LI> Kinematic analysis is proposed for estimating a blade's edge position and orientation. </LI> <LI> We performed an experiment to estimate the position of the blade's edge while driving. </LI> <LI> Also, we have verified that its performance has an error within 30 mm. </LI> </UL> </P>

A Position and Velocity Estimation Using Multifarious and Multiple Sensor Fusion

Youngwan Cho,Heejin Lee 한국지능시스템학회 2017 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.17 No.2

In this paper, we propose a fusion algorithm of multifarious and multiple sensors to enhance the accuracy and reliability of position and velocity estimation for the vehicles. We proposed an adaptive Kalman filter for multiple sensor fusion to provide a fault tolerant estimation. We verified the multiple sensor fusion estimator can provide a fault tolerant estimation through Matlab simulation and laboratory equipped experiments. We also proposed a fusion algorithm of multifarious sensors in order to enhance the velocity estimation accuracy. We proposed a Kalman filter error correction for compensate the accumulative error in the main sensor with the other type of sensor which has characteristic of biased error. We also developed a fusion algorithm for compensate the error in the position measuring with the velocity measuring. We made experiments for estimating position and velocity of vehicle simultaneously through the fusion of multifarious and multiple sensors and showed that average position error was 1.5764 m and average velocity accuracy was 99.81%.

Sensorless initial position estimation strategy for PMa‑SynRM drives based on dual rotating high‑frequency signal injection

Liu Liu,Pan Luo,Junjie Zhao,Yuechen Rui 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.11

The rotating high-frequency (RHF) signal injection method is widely adopted for the initial position estimation in sensorless permanent magnet-assisted synchronous reluctance motor (PMa-SynRM) drives due to its simple implementation. However, the position estimation accuracy of the conventional method may be seriously deteriorated by the dead-zone effects of the inverter and the cross-saturation effects of the machine. Thus, to improve initial position estimation accuracy, a strategy to apply dual RHF signals is proposed in this paper. Different from the traditional solution, the proposed method sequentially injects dual RHF carrier voltages with the same frequencies but different amplitudes into the machine. Objective equations that consider the dead-zone and cross-coupling effects can be extracted from high-frequency response currents in turn. After the simple calculation, the initial position can be obtained directly and accurately, which effectively minimizes the influences of machine cross-saturation and inverter nonlinearities. The influence of the system delay on the rotor position estimation is also analyzed and deduced in detail. Finally, experimental results on a 5.5-kW PMa-SynRM indicate that the proposed method can achieve precise initial position estimation under any rotation position.

이동물체의 위치측정을 위한 PSD 센서 시스템 연구

盧瑩植 울산대학교 1996 공학연구논문집 Vol.27 No.1

평면상에서 이동하는 물체(이동로봇, 등)가 공간상에 놓여진 자신의 위치를 측정하기 위하여 사용되는 능동 등대 방식의 센서 시스템을 PSD(Position Sensitive Detector)를 이용하여 개발하였다. 여러 광원들을 이동공간 상부에 드문드문 배치하고 이들을 이동체상의 PSD센서로 검출함으로써 상대적인 위치를 측정하도록 하였다. 광원과 이동체의 위치에 대한 모델의 내부 파라미터 켈리브레이션을 위하여 LSE(Least Square Estimation)방법이 도입되었다. 이동체의 초기위치가 알려져 있지 않은 경우 이치가 알려진 두개 이상의 광원 검출에 의하여 초기위치를 측정하였다. 또한 이동 중에는 광원 정보와 Dead Reckoning 정보를 이용한 확장된 칼만 필터로 계산하였다. 이동로봇을 이용한 실제 실험을 통하여 제안된 시스템으로 부터 얻은 위치 정보는 충분히 활용 가능한 정도의 정확성이 있음을 보였다. An active beacon localization system using PSD(Position Sensitive Detector) is developed that estimates position for moving objects - mobile robots et al. - in 2D plane. We place several light sources sparsely over the work space as beacons(or landmarks), so that the moving object can correct its estimated position when detecting the beacon by PSD sensor. An LSE(Least Square Estimation) method is introduced to calibrate internal parameters of a model for the beacon and the object position. When the object position is unknown, the initial position can be estimated by the detection for two or more light sources which positions are known. During movement, the position can be calculated by the IEKF(Iterated Extended Kalman Filter) applied to the beacon and dead-reckoning data. Practical experiments show that the estimated position obtained by this system is precise enough to be useful.

초기위치추정 정확도 향상을 위한 가버 웨이블릿 기반 필터 링 기법

김진용,박종은,김은경,김성신 한국지능시스템학회 2019 한국지능시스템학회논문지 Vol.29 No.5

AGV based on SLAM using LRF should estimate the initial position by using global map at initial operation. However, there is a problem that it is difficult to find the initial position of the AGV, because little environmental information is obtained through the LRF sensor. In this paper, to solve this estimation of initial position problem, the estimation method based on the geometrical characteristics of the 3D coordinate information and the feature information of the image obtained through the stereo camera is used. We propose a method of improving the accuracy of initial position estimation by filtering mismatches using Gabor wavelet in performing the feature matching during the position estimation step for improving the accuracy of initial position estimation. The experimental results show that the proposed method can improve the accuracy of the estimated initial position. LRF를 이용한 SLAM 기반 AGV는 초기 가동 시 전역지도를 이용하여 초기위치를 추정해야한다. 하지만, LRF 센서를 통해서얻을 수 있는 환경정보가 적기 때문에, AGV의 초기위치를 찾기 어렵다는 문제가 있다. 본 논문은 이러한 초기위치추정문제를 해결하기 위해 스테레오 카메라를 통해 얻은 이미지의 특징 정보 및 3D 좌표 정보의 기하학적 특성을 이용하여초기위치를 추정하는 방식을 이용하였다. 보다 정확한 위치 추정을 위해, 위치 추정 단계 중 특징 매칭을 하는 수행하는단계에서, 가버 웨이블릿을 이용하여 오매칭을 필터링함으로써 초기위치추정 정확도를 향상시키는 방법을 제안한다. 실제계측 데이터를 이용하여 초기위치추정 실험을 수행한 결과, 오매칭 필터링 과정을 수행하지 않았을 때보다 위치 추정정확도가 향상됨을 확인하였다.

Mathematical Analysis and Simulation Based Survey on Initial Pole Position Estimation of Surface Permanent Magnet Synchronous Motor

Kim, Tae-Woong,Wheeler, Patrick,Choi, Jae-Ho The Korean Institute of Power Electronics 2009 JOURNAL OF POWER ELECTRONICS Vol.9 No.3

In this paper, the initial pole-position estimation of a surface (non-salient) permanent magnet synchronous motor is mathematically analyzed and surveyed on the basis of simulation analysis, and developed for accurate servo motor drive. This algorithm is well carried out under the full closed-loop position control without any pole sensors and is completely insensitive to any motor parameters. This estimation is based on the principle that the initial pole-position is simply calculated by the reverse trigonometric function using the two feedback currents in the full closed-loop position control. The proposed algorithm consists of the predefined reference position profile, the information of feedback currents, speed, and relative position, and the reverse trigonometric function for the initial-pole position estimation. Comparing with the existing researches, the mathematical analysis is introduced to get a more accurate initial pole-position of the surface permanent magnet motor under the closed-loop position control. It is found that the proposed algorithm can be easily applied in servo drive applications because it satisfies the following user's specifications; accuracy and moving distance.

Mathematical Analysis and Simulation Based Survey on Initial Pole Position Estimation of Surface Permanent Magnet Synchronous Motor

Tae-Woong Kim,Patrick Wheeler,Jaeho Choi 전력전자학회 2009 JOURNAL OF POWER ELECTRONICS Vol.9 No.3

In this paper, the initial pole-position estimation of a surface (non-salient) permanent magnet synchronous motor is mathematically analyzed and surveyed on the basis of simulation analysis, and developed for accurate servo motor drive. This algorithm is well carried out under the full closed-loop position control without any pole sensors and is completely insensitive to any motor parameters. This estimation is based on the principle that the initial pole-position is simply calculated by the reverse trigonometric function using the two feedback currents in the full closed-loop position control. The proposed algorithm consists of the predefined reference position profile, the information of feedback currents, speed, and relative position, and the reverse trigonometric function for the initial-pole position estimation. Comparing with the existing researches, the mathematical analysis is introduced to get a more accurate initial pole-position of the surface permanent magnet motor under the closed-loop position control. It is found that the proposed algorithm can be easily applied in servo drive applications because it satisfies the following user’s specifications; accuracy and moving distance.

Human Body Position Estimation System using Electric Field Resonance Coupling

Shimon Ajisaka,Sousuke Nakamura,Kiyoaki Takiguchi,Akira Hirose,Hideki Hashimoto 제어로봇시스템학회 2010 제어로봇시스템학회 국제학술대회 논문집 Vol.2010 No.10

Today in terms of security and caring, more various and robust information system about human existence in indoor environment (ex. rooms, buildings) are needed. Especially, human position estimation system in such kinds of spaces is basic. Generally, such kind of systems use radiowave devices, cameras and ultrasonic devices to estimate human position. But these kind of systems have some weakpoint when the system tries to estimate position. A purpose of this paper is to propose novel human position estimating system using electric field resonance coupling and validate the evidence for possibility of human position sensing system using resonance coupling by simulation experiment. In simulation experiment results using Gabriel"s human phantom, relation between electric field strength and distance between sensor and human are confirmed. In conclusion, feasibility of the proposed human position estimation system is shown.

Inertial Sensor-Based Relative Position Estimation between Upper Body Segments Considering Non-Rigidity of Human Bodies

이창준(Chang June Lee),이정근(Jung Keun Lee) Korean Society for Precision Engineering 2021 한국정밀공학회지 Vol.38 No.3

Estimation of the relative position between the body segments is an important task in inertial sensor-based human motion tracking. Conventionally, the relative position is determined using orientations and constant segment vectors that connect from segment to joint center, based on the assumption that the segments are rigid. However, the human body segments are non-rigid, which leads to an inaccurate relative position estimation. This paper proposes a relative position estimation method based on inertial sensor signals, considering the non-rigidity of the human bodies. Considering that the effects of non-rigidity are highly correlated with a specific variable, the proposed method uses time-varying segment vectors determined by the specific physical variable, instead of using constant segment vectors. Verification test results for an upper-body model demonstrates the superiority of the proposed method over the conventional method: The averaged root mean square error of the sternum-to-forearm estimation from the conventional method was 34.19 ㎜, while the value from the proposed method was 16.67 ㎜.

신체 분절의 연조직 변형을 고려한 관성센서신호 기반의 상대위치 추정 칼만필터

이창준 ( Chang June Lee ),이정근 ( Jung Keun Lee ) 한국센서학회 2020 센서학회지 Vol.29 No.4

This paper deals with relative position estimation using a Kalman filter (KF) based on inertial sensors that have been widely used in various biomechanics-related outdoor applications. In previous studies, the relative position is determined using relative orientation and predetermined segment-to-joint (S2J) vectors, which are assumed to be constant. However, because body segments are influenced by soft tissue artifacts (STAs), including the deformation and sliding of the skin over the underlying bone structures, they are not constant, resulting in significant errors during relative position estimation. In this study, relative position estimation was performed using a KF, where the S2J vectors were adopted as time-varying states. The joint constraint and the variations of the S2J vectors were used to develop a measurement model of the proposed KF. Accordingly, the covariance matrix corresponding to the variations of the S2J vectors continuously changed within the ranges of the STA-causing flexion angles. The experimental results of the knee flexion tests showed that the proposed KF decreased the estimation errors in the longitudinal and lateral directions by 8.86 and 17.89 mm, respectively, compared with a conventional approach based on the application of constant S2J vectors.