A Simple Method to Improve Autonomous GPS Positioning for Tractors

1、Precision Agriculture 精细农业精细农业 A Simple Method to Improve Autonomous GPS Positioning for Tractors Xiang shiSelf-introductionResearch focuses on the technology of computer control, Vehicle electronic control and intelligent technology, and the integration technology of agricultural machinery.RewardIn

2、 2012, I won the three prize of progress in science and technology. a leader who was responsible for a number of projects subjects, such as development plan of innovation team, agricultural research of outstanding talent and innovation team, national eleven five science and technology support and so

3、 on. NAME：Shi Xiangthe Mechanical and Electronic Engineering of Henan Shaolin University（8610）1234567Z“Precision Agriculture ” is a new concept to manage agricultural production system based on information and knowledgeIts practice will promote applied research for reconstruction of conventional agr

4、iculture and improvement of agricultural equipment technical level. It has revolutionary meanings for initiation of agricultural production process scientific management and agricultural sustainable developmentThe extension of precision agriculture in China will be developed gradually in due order。P

5、recision Agriculture 精细农业精细农业Precision Agriculture 精细农业精细农业1.IntroductionAutomationNavigationIncreased productivityApplication accuracyOperation safetyVarious guidance technologies1. mechanical guidance2. Machine vision guidance3. radio navigationA new generationTrendA new generationErrors are alway

6、s presentBUT(INS)Inertial Navigation System Employing more precise GPS receiverPlacing the GPS receiver ahead of the tractor (A NEW POSITION)Expensivecomplex Common solution A new solution SimpleLow costPrecision Agriculture 精细农业精细农业2.method1。Kinematic Model(运动模型) 2。Position and Orientation Computat

7、ion of the Rear Axle Midpoint from GPS Positions：method 13。Position and Orientation Computation of the Rear Axle Midpoint from GPS Positions：method 24。Control Law 1。Kinematic Model(运动模型) Assuming no-slip conditions on the wheels, the kinematic model of the vehicle is given by: Figure 1. Tractor sche

8、matic and variables description. 2。Position and Orientation Computation of the Rear Axle Midpoint from GPS Positions：method 1Figure 2. The position and orientation at the midpoint of the rear axle (x, y, ) have to be computed from positions received from the GPS placed in a forward position (xG, yG)

9、. 3。Position and Orientation Computation of the Rear Axle Midpoint from GPS Positions：method 2Figure 3. Two near positions of the tractor when following a curved trajectory. 4。Control Law The control law employed by Noguchi et al. ，Stoll et al. and Nagasaka et al. ，among others, which is given by Eq

10、uation ，was chosen to test the system. It is one of simplest used in agricultural GPS guidance select proper K1 and K2SubsequentlyPrecision Agriculture 精细农业精细农业Experimental System Figure 5 。(a) 6400 John Deere tractor used in the tests. The red circle indicates the position of the Haicom HI-204III n

11、avigation GPS, the blue circle the position of the Trimble R4 reference GPS, the orange circle the position of the magnetic encoder, and the yellow circle the position of the DC motor and pulley. (b) Magnetic encoder used for measuring the steering angle. (c) DC motor and pulley used for moving the

12、steering system. Details about experimentFigure 6. Different positions of the Haicom HI-204III navigation GPS in the field tests. The navigation sensor position is highlighted with a red circle. (a) The guidance GPS placed in the back part of the cabin over the real axle. (b) The guidance GPS placed

13、 3 m ahead of the rear axle of the tractor. (c) The guidance GPS placed 5 m ahead of the rear axle of the tractor. Three placements of the navigation GPS in the field tests at 0, 3 and 5 meters Precision Agriculture 精细农业精细农业Results and Discussion Figure 7. (a) Simulation results obtained when the tr

14、actor follows a straight line and experimental errors are added. (b) Simulation results obtained in a step response trajectory when experimental errors are added. Straight line and step response tracking. Figure 8. (a) Distance error from a desired straight trajectory at 1 m/s with the GPS placed at

15、 0, 3 and 5 meters from the rear axle of the tractor. (b) Step response tracking at 1 m/s with the GPS receiver placed at 0, 3 and 5 meters from the rear axle of the tractor. contrastFigure 9. (a) The straight line represents a trajectory followed by a tractor and the dots represent the positions pr

16、ovided by a GPS receiver placed on the tractor. (b) Trajectory of the rear axle of a tractor that turns (red) and trajectory of a GPS placed ahead of the same tractor (blue). (c) Trajectory of the rear axle of a tractor that goes straight (red) and trajectory of a GPS placed ahead of the same tracto

17、r (blue). (d) Directions with respect to the tractor orientation where the proposed method improves the positioning (green) or does not improve the positioning (red). analysisThe proposed method improves tractor positioning when only a GPS receiver is used as the positioning sensor. The improvement

18、in the positioning occurs in the tractor orientation and in the positioning with respect to the transverse axis of the tractors orientation.summaryPrecision Agriculture 精细农业精细农业Thank you A Simple Method to Improve Autonomous GPS Positioning for Tractors Tractor guidance systems sometimes employ more

19、 positioning sensors, such as: (i) tilt and (ii) orientation sensors. When a tilt sensor is employed together with the GPS receiver, it is expected that the proposed method will also improve the positioning, but with a lower ratio. This is because in this situation the proposed method reduces only the GPS positioning