http://www.ifac-papersonline.net/ en Copyright 10:38 AM Saturday 18, 2013 IFAC-PapersOnline http://www.ifacpapersonline.com 10:38 AM Saturday 18, 2013 10:38 AM Saturday 18, 2013 ET webmaster@ifac-papersonline.net webmaster@ifac-papersonline.net http://www.ifac-papersonline.net/Control_in_Transportation_Systems/11th_IFAC_Symposium_on_Control_in_Transportation_Systems__2006_/rss.html http://www.ifac-papersonline.net/Detailed/42773.html 04:00 PM Wednesday 31, 1969 http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/42774.html 04:00 PM Wednesday 31, 1969 http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/42775.html 04:00 PM Wednesday 31, 1969 In the future, European farmers will have to effectively manage information on and off their farms to improve economic viability and to reduce environmental impact. To this end, an integrated information system is needed to advise managers of formal instructions, recommended guidelines and implications resulting from different scenarios at the point of decision making during the crop cycle. This will be enabled through better decision making by the farm managers with the help of a management information system. Such an information system has been defined; both its internal parts and the required infrastructure to support it. FutureFarm is an EU funded 3-year project involving 15 partners from 10 EU countries. The project addresses wide issues of development from public awareness, decision support, compliance to recognized management standards, socio-economic impact, energy efficiency, biofuels and robotics. The core technology has to take the already extensive experience in Precision Farming research and integrate it into a farmer-based prototype system. In FutureFarm the appropriate tools and technologies have been conceptually designed, prototypes developed and evaluated under practical conditions. Precision Farming as well as robotics are very data intensive and provide a wealth of information that helps to improve crop management and documentation. Based on these technologies a Farm Information Management System has been developed to deal with the information intensive farm of the future. This paper describes the outcomes of the FutureFarm project for the first two years of its duration. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/42776.html 04:00 PM Wednesday 31, 1969 A survey is presented of the literature on greenhouse climate control, positioning the various solutions and paradigms in the framework of optimal control. A separation of timescales allows the separation of the economic optimal control problem of greenhouse cultivation into an off-line problem at the tactical level, and an on-line problem at the operational level. This paradigm is used to classify the literature into three categories: focus on operational control, focus on the tactical level, and truly integrated control. Integrated optimal control warrants the best economical result, and provides a systematic way to design control systems for the innovative greenhouses of the future. Research issues and perspectives are listed as well. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/42777.html 04:00 PM Wednesday 31, 1969 Soil texture has an important influence on agriculture, affecting crop selection, movement of nutrients and water, soil electrical conductivity, and crop growth. Soil texture has traditionally been determined in the laboratory using pipette and hydrometer methods that require a considerable amount of time, labor, and expense. Recently, in-situ soil texture classification systems using optical diffuse reflectometry or mechanical resistance have been reported, especially for precision agriculture where more data is needed than in conventional agriculture. This paper is a part of overall research to develop a soil texture classification system using image processing. Application of image processing was motivated by simple traditional approaches such as visual inspection and the "hand-feel" method. In this paper, the potential of soil texture classification using RGB histograms was investigated. Seven sites representing major Korean paddy soil series were selected, 4-6 core samples up to a 50-cm depth were obtained from each site, and each sample was segmented by 5-cm intervals. For each segmented soil sample, four surface images were taken using a miniaturized CCD camera, and texture fractions were determined by the pipette method. Scatter plots showed linear patterns between silt content and histogram variables such as brightness, skewness, and mode - brightness. When 5% averaged silt content was linearly regressed with mode - brightness, R2, RMSEC, and RMSEP were 0.96, 2.2%, and 6.3%, respectively. When soils were classified using USDA criteria, the laboratory method and the in-situ image processing method produced the same results for 48% of the samples. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/42778.html 04:00 PM Wednesday 31, 1969 The objective of this study was a design a new water level sensor for irrigation water measurement to reduce the investment of water measuring equipment required for agriculture management. Based on ultrasonic pulse-echo technology, a new hardware structure including an ultrasonic transmission circuit, echo receiver circuit, data output circuit and micro control unit (MCU) were described in this paper. A specially designed pulse transformer and a drive circuit based on the NEC555 were used to improve the driving capability for ultrasonic transducers. A low cost but has a high quality for accepting circuit was adopted based on Sony Corporation's infrared demodulator, CX20106A. Output circuit which based on the RS232 interface using multichannel RS-232 Drivers-Receivers MAX232 was used to output the dates, this circuit is simple and easy to extend. In addition, an IC card (corn is 64K SPI Bus Serial EEPROM, AT24C64) based correction parameters input circuit was adopted. Furthermore, some factors, such as temperature, water surface fluctuation and process response time etc. which influence accuracy were discussed. Then, the corresponding corrections methods not only include hardware methods but also include software methods were proposed. A temperature detection module which based on a digital sensor, the Dallas Semiconductor™ DS18B20, was added to the hardware systems. At the same time, in order to reduce the process response time of program written in C51 language in the MCU control system, the integration programming technology using C51 language and assembler language was used. Besides, voltage conversion and power supply circuits based on three-port voltage regulator circuit LM7805 and LM7808 was designed. The test result shows that this design has a high accuracy and stability. It is possible to get water level data with small errors, and this design reduces the production cost. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/42779.html 04:00 PM Wednesday 31, 1969 GPS has become a common technology for a positioning system of vehicles outdoor. In agriculture, the RTK-GPS has been used for autonomous tractors and harvesters in researches, and their measurement accuracy was sufficient. In room, however, the GPS measurement errors were larger because of delayed or covered electric waves. Rail or electromagnetic induction type position sensing methods have been used for autonomous mobile robots under greenhouses or other facilities. There are problems that installation costs are expensive and route modification is not easy, when those systems are used in agricultural facilities. In this research, a positioning system using spread spectrum sound is described and noise tolerance and signal identification could be improved by using a spread spectrum technique. So far, a system for measuring distance was developed and estimation of measurement accuracy was conducted. As a result of measurement distance 10m between microphone and speaker under non wind and non temperature gradient, RMSE 3.4mm was obtained. It is also known, however, the measurement error increases under windy and changeable temperature conditions. In this research, a correction method of the measurement error by wind and temperature is developed and estimated. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/42780.html 04:00 PM Wednesday 31, 1969 We present preliminary work towards developing electronic traps for automated monitoring of insect populations. The proposed system has the potential to significantly reduce the cost of integrated pest management programs by automating the labor-intensive operations of monitoring insect populations. In addition, the proposed system will provide unprecedented real-time, high-resolution insect population data to growers. We present the design and implementation of two electronic trap prototypes, one based on light dependent resistor (LDR) sensors and the other based on infrared (IR) sensors. Both prototypes use a commercially available bucket trap as a base frame. Using an on-board microcontroller, the electronic traps are able to detect target insects entering the trap and record each event with a corresponding timestamp. We report the results of field tests that were performed in apple orchards in Pennsylvania and Washington in 2009. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/42781.html 04:00 PM Wednesday 31, 1969 The mechanical impedance of soil is well known to influence the shape formation of storage roots of root vegetables strongly. Contact interaction between the root and soil become important in the growth and shape formation of the storage root. This study was aimed at construction of a numerical model for thickening growth of radish tap roots based on the root-soil contact interaction. However in 2D simulation, the height of the soil Discrete Elements increased greatly compared with experimental observations. To solve this problem, 3D simulation was extended and improvements in the shape representation of soil Discrete Elements were made. Soil Discrete Elements with non-spherical shape were generated such that several spherical Discrete Elements were joined together to create a model particle. In this report, the results of preliminary simulation obtained for a small scale are discussed. For the 3D simulation, the shape of root Finite Elements was reproduced based on growth velocities. No distortion occurred in root Finite Elements. Additional examinations of the mechanical properties of radish roots and parameter settings for root Finite Elements are needed. Furthermore, results confirmed that the extension of FE-DEM for the root-soil system in 3D was able to decrease the final height of surface soil Discrete Elements from 18 mm to approximately 14 mm. Clumped Discrete Elements decrease the height to about 13 mm. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/42782.html 04:00 PM Wednesday 31, 1969 For this study, we applied a finite element-discrete element method (FE-DEM) to predict the tractive performance of an elastic iron wheel for mobile robots running on sand. We developed our program, where FEM is applied to a wheel and a subsurface soil layer, and where DEM is applied to the surface soil layer where the contact interaction between the tire and soil is greatest. The developed FE-DEM tool was found to have sufficient accuracy to predict the performance of an elastic wheel running on deformable soil. Moreover, parametric analysis was applied for those parameters of the rigidity of the tread part of the wheel, the surface soil layer thickness, and the lug height. The effect of rigidity of the tread part was negligible for 1-5 MPa. The surface soil layer thickness was found to have no significant effect on tractive performance. The lug height showed a strong effect on the tractive performance of the wheel, but the effect on net traction seemed to be degraded concomitantly with the increase in lug height. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/42783.html 04:00 PM Wednesday 31, 1969 We focused on the cone penetration and proposed an approach called mesoscopic soil model, by which we could develop a virtual numerical model at an intermediate scale of element diameters without sacrificing the simplicity in application of Discrete Element Method DEM. Along with the experiments on mesoscopic soil model, we have developed a 2D DEM program with circle element for cone penetration analysis. In our DEM, the rolling friction was introduced to avoid excessive element rotation of circular element. The result of DEM analysis on cone penetration resistance for mesoscopic soil model showed that the developed program had sufficient accuracy in the prediction of penetration resistance against mesoscopic model. For real sand, not only the spring constants but also the elemental density in DEM was modified to obtain comparable results as in the experiment. Introduction of clumped element was also discussed to investigate the effect of particle shape of real sand. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/42784.html 04:00 PM Wednesday 31, 1969 The main challenge when controlling agricultural machinery is the biological variability of the incoming crop. This variability renders any process model time-variable and uncertain. Most robust control techniques start with a computationally intensive initialisation method which has to be repeated each time the model changes. Moreover, these techniques mostly focus on process stability, and not process performance. In this paper a different approach is taken with focus on process performance and attention for the computational complexity. The Stochastic MPC framework is used to design a controller that responds as swiftly as possible at all times. Two models are defined, one for the process variables and one for the model error on each of the process variables. The actual configuration parameters of the Model-based Predictive Controller are then calculated in each time step based on the operator settings and the estimated model error. The model error is also used to convert the deterministic process constraints into stochastic constraints which are respected with a given accuracy. Finally this approach is implemented and validated on a capacity control system for a combine harvester. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/42785.html 04:00 PM Wednesday 31, 1969 Transplanting is one of the most important operations during vegetable and flower production. Because of the higher labor intensity and lower efficiency for the operation by hand, it is difficult to enlarge production scale. So, it has become an urgent task to achieve automation of plug seedling transplanting for Chinese horticulture industry. In this paper, on the basis of knowing the development of transplanting technology and transplanter both domestic and abroad, a simple, practical and automatic transplanter for plug seedling, including manipulator, conveyor system for plug tray and flowerpots, overall structure and control system based on PLC was designed. Finally, Prototype was manufactured and performance tests were conducted. Results showed that the automatic transplanter had reliable transplanting performance. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/42786.html 04:00 PM Wednesday 31, 1969 Current mechanical cherry harvest uses either impact or vibration excitations to shake tree branches to create a detachment force on cherry stems to remove cherries from the tree. A comprehensive understanding of fruit detaching energy distribution on cherry trees is essential for designing such mechanical cherry harvesters. This research was conducted to quantify the dynamic response of cherry trees to forced oscillating excitation. In this study, a set of accelerometers were placed at different locations on a sweet cherry tree. Acceleration signals at those locations corresponding to a band of sinusoidal excitations ranging from 2 to 40 Hz, covering the most commonly used excitation frequencies in vibrating harvest, were recorded and then integrated into velocity and displacement responses. A peak excitation force of 28.9 N was used at all excitation frequencies. Results showed that the first two resonant frequencies of the test cherry tree were around 6 and 14 Hz, respectively. The responding displacement at monitoring locations ranged from 1 mm to 11 mm under the first two resonant frequencies. The third resonant frequency was found at around 25 Hz, under which the responding displacement were noticeably lower than the corresponding values at the first two resonant frequencies. Under the same force excitation amplitude, the displacement responses of most branches increased as the location is further away from the excitation point. Experimental results also indicated that the vibratory energy of each branch in the path from the excitation point to the terminal branch was transmitted and observably amplified along the straight transmission path without branch junctions at all resonant frequencies. It implies that cherry trees with simple structure, straight branch orientation and less branch junction will have higher harvest efficiency when in impact or vibration harvesting. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/42787.html 04:00 PM Wednesday 31, 1969 This paper proposes a new approach and modeling of hydraulic arms for vegetable cropping. First, we show the actual nonlinearity of hydraulic arms experimentally via the subspace system identification. Second, we give a new canonical form of hydraulic arms based on Casimirs and confirm the validity by experiments. Furthermore, we propose an additional nonlinear component for the internal structure and confirm the validity by experiments. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/42788.html 04:00 PM Wednesday 31, 1969 To reduce the labor involved in strawberry production, we have developed a strawberry harvesting robot that can operate on a hanging bench culture. In the hanging bench culture, a plant is grown on a bench that has been hung from a beam of the greenhouse. The bench is set at a height of approximately 1.0 m from the floor. In general, mature fruits are located behind immature fruits as viewed from the aisle side. In such a case, a conventional robotic harvester tends to fail in approaching the target fruit because of obstacles such as neighboring immature fruits. As viewed from the hanging bench side, mature fruits are located in front of the immature fruits. Considering this case, our robot has a unique feature that it approaches the target fruit from the hanging bench side and positions itself right below the hanging bench. We have developed a traveling platform for the robot to traverse on and accomplish complete harvesting tasks in a 2D area in a greenhouse. The traveling platform has a gantry structure that moves on a set of three rails. The performance of the traveling platform has been tested, and basic stable movements have been observed in the transverse and the path direction. A negative longitudinal slippage has been observed when a weight of 200 kg was loaded. Basic performance tests of the robotic harvester have confirmed that the robot can successfully harvest mature fruits. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/42789.html 04:00 PM Wednesday 31, 1969 Mixed-flow dryers are continuous dryers for fluxionary bulk material as grain, granulates from renewable materials etc. These types of dryers are segmented in a number of air inlet and outlet sections which are regularly operated. Principally, the bulk material can not be ventilated homogeneously. Therefore, a non-homogeneous temperature and moisture distribution inside the bulk is developing during ventilation under normal operation. Partially over dried and under dried material is the result. A mathematical model has been developed based on Potential Theory of the Complex Analysis for the air flow distribution through the bulk material. With this model a control strategy can be developed and analyzed to control air inlet flow and air temperature to equalize the temperature distribution inside the dryer. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/42790.html 04:00 PM Wednesday 31, 1969 This paper describes the investigation of low power laser beam application to corn kernels using kernel moisture as a control parameter. Kernel moisture was measured according to HRN ISO 6540:2002 procedure. Two red laser sources of 100mW and 200mW, λ= 632nm, were used in experiments, both with different exposure time. The power density of laser beam was in range from 0.5mJ/cm2 to 20mJ/cm2. Corn kernels were humidified in seven grades: between 15% and 31% of kernel moisture. All groups of corn kernels were exposed to laser beam for four different exposition times. After laser beam treatment corn kernels moisture was determined by the same HRN ISO 6540:2002 procedure. Obtained results exhibit a high nonlinearity effect giving unexpected increase in moisture for 0.62 % for specific initial moisture and for specific exposition time. Also, the decrease of moisture for 0.5 % was observed for specific lower initial moisture and specific exposure time. The effects are now under further cross-examinations. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/42791.html 04:00 PM Wednesday 31, 1969 A mobile grading machine was earlier developed to establish precision citrus fruit production. This machine could travel in citrus orchards and measure appearance and internal qualities of fruit harvested by humans on-site. In addition, it could record harvesting date and fruit locations. It consisted of a mobile mechanism, a differential global positioning system, a fruit conveyor system, two machine vision systems (one for fruit inspection, the other for trees monitoring), a sugar content measurement system using a near-infrared (NIR) spectrometer, and a personal computer for control and database. The color, size, and sugar content of each fruit and leaf color of each tree were measured by the machine vision devices and the NIR inspection system. As fruit features were extracted based on image analysis by the machine vision system, it was observed that the result of size had a correlation with actual citrus size and the result of color was accurately compared with human eyes. However, it was considered that the lighting device positions should be changed for higher quality images, because the edges of the fruit were dark due to radiation angles. This paper reports on moves of the lighting device position and to obtain lower light radiation angles so that the estimate of fruit size could get higher correlation with the actual fruit size. Furthermore, the earlier results of sugar content measurement had a low correlation with the actual brix values because the sensing head of NIR inspection system was pressed to each fruit from the top. The pressing direction was changed to from the side to obtain higher performance of the system. The improvements caused higher correlations of the sensor outputs to the fruit size and sugar content. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/42792.html 04:00 PM Wednesday 31, 1969 To clarify the characteristics of grape flesh texture, acoustic vibrations generated by inserting a probe in grape flesh were measured. Texture index (TI) based on energy density, which was calculated from vibration signals, could be used to classify 9 grape cultivars into 3 groups with their flesh textures evaluated as crisp, nonscrisp, and intermediate, while breaking froce measured by a conventional intrusive method did not. TI of 0-50-Hz band correlated with the breaking force, suggesting that TI of 0-50-Hz corresponds to flesh firmness, and TI of higher frequency characterizes crispness of grape flesh. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/42793.html 04:00 PM Wednesday 31, 1969 In order to improve apples quality, many methods have been done on planting, harvesting and storing. However, mould core apples are caused by fungi or/and humid storage condition. Therefore, mould core apples should be selected as the last step to improve the apples quality before selling. This paper describes a detection system depending on X-ray technology, which can get the internal image of the detection objection, to detect the mould core apples. Nevertheless, X-ray is always avoided in the fruit detection because of the radiation of X-ray and the food safety. This paper solves this problem by using a low-level radiation of X-ray radiant. However, the low-level radiation of X-ray radiant generates a low contrast image, which raises a problem in X-ray image processing because it is difficult to distinguish the background and foreground in the low contrast image. in order to perform successful detection of mould core apple, in this paper, firstly, the Wiener filter is utilized for decreasing the image noise from the camera or/and X-ray machien imaging system. The, the X-ray image is enhanced using contrast enhancement method to solve the problem of low contrast X-ray image. Thridly, the mould core area is extracted by region recognition and edge detection method after using Lifting Wavelet Transform (LWT). Finally, support vector machine (SVM) is utilized to classify the mould core apple. The experiment results show that the image processing and classification method could detect mould core apple with a success rate of 95%. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/42794.html 04:00 PM Wednesday 31, 1969 Daily work is very tough in orchard on slope land. Assistant robots are required to develop for workers. In this paper, an autonomous vehicle in orchard is provided as a base platform which is used for monitoring, pesticide spraying, harvesting and so on in the near future. The self-position identification is attained by using a laser range finder and map matching. The robust nonlinear control method which was proposed by authors for underactuated mobile robots is applied to the vehicle which is a by-wire all terrain one. A desired path to follow is generated at first. If the vehicle is a little far away from the desired path, another desired path from the current position is regenerated to cancel the current path error and smooth motion is achievable because in the case of underactuated systems sometimes a path error causes large motion of a vehicle. Experiments were performed in orchard. The experimental results were very fine to go through the orchard. The average path error in the lateral direction is about 20cm. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/42795.html 04:00 PM Wednesday 31, 1969 So called automatic guidance systems are becoming more common in agricultural tractors, so that a driver does not need to steer the vehicle. The systems are mostly relying on GPS with correction. However, these systems usually steer only the tractor itself, despite the fact that the implement is the one that has to be run side by side with the previous swath. With towed implements, or trailers, it is not easy to keep the position of implement on track if the angle of the steering wheels of a tractor is the only resource under control. In this paper, a system with a standard tractor with front steering wheels and an active joint in the drawbar of the trailer are both controlled by the automatic guidance system. Besides, the positioning is not only based on GPS, but also with a local sensor that detects an edge of the previous swath; and this sensor is installed on the trailer. To control this system with two inputs and two outputs with nonlinear kinematics, a multivariable controller is needed for trajectory control. In the paper, an approach to the trajectory control in case of the tractor-trailer system with nonlinear model predictive control (NMPC) is studied. The test results show that the performance is better than with linear model predictive control that was tested in earlier study. Tests were done in driving speeds 8, 10 and 12 km/h. In a curved path, the tractor following error was typically less than 12 cm and in the implement less than 8 cm. The constant control cycle is achieved by alternating the prediction horizon length. By that way, the best possible solution is always gained at the limits of computation time. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/42796.html 04:00 PM Wednesday 31, 1969 This paper presents a simulation framework and realization for a tractor-trailer system with an active joint in an agricultural field setting. In addition, all real system measurements are also provided for hardware-in-loop testing. In the simulator, the kinematics and dynamics of the tractor and the trailer are modelled, as well as noises related to each measurement. The noise statistics and typical amount of wheel slip were identified from field tests. For hardware-in-loop testing the simulator provides the measurements in CAN-bus (ISO 11783 standard) and the commands to the steering valve are also received via the bus. CAN-bus is the only link between the guidance system under test and the simulation environment. In addition, the simulation environment contains a graphical front end, where the trajectories of the vehicle can be observed and analyzed. The most challenging noise related to the simulation of an environment is related to the GPS and its inaccuracies, as the noise properties are far from Gaussian white noise. In this paper an error model for GPS noise is presented as a position measurement and noise range statistics to the measurement. The simulation environment is tested with nonlinear model predictive control algorithms. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/42797.html 04:00 PM Wednesday 31, 1969 The objective of this study is to detect the cut-edge and the stubble lines of rice plants in the images that are captured with a camera for an auto-steering system of a head-feeding combine harvester. The scene images were acquired with the monochrome CCD camera equipped with an infrared bandpass filter at 850 nm. The camera was mounted on the combine's cab. Graphic charts that represent the distribution of the gray level values were used for detection of the cut-edge. However, the cut-edge of rice was not well detected. Next, the stubbles, the short pieces left after the crop is cut, were detected. The averages of the angle error and the offset by stubble line detection were 7.65°, and 11.4 cm, respectively. The system and algorithm can be used for combine steering in rice harvest. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif