Study On Feeler Based Guidance System With Electro-Mechanical Servo Following Stubble

Planting wheat without tillage after maize harvesting is a hard problem through the extension of conservation tillage technology system in the district of two crops one year in north china. For this problem, an idea of sowing wheat following the maize rows is presented by conservation tillage research center in China Agricultural University. A no-till wheat planter following this concept is designed out with opener moving ahead between two rows of maize stubble and preventing from impacting them. This objection achieved relaying on the driver and his experience. The maize row space is 600mm and that of wheat is 150mm. Three rows of wheat is sown between two maize rows and the space from opener outboard side to maize stubble is theoretically about 150mm. In view of root radius of about 30~50mm of the stubble, individual maize offset from beeline is about 20mm resulting in the steering offset by drivers within 100mm. If planter is steered over this offset distance, it is frequent to occur with stubble impaction by the opener and implement blockage and planting quality degradation. But so narrow offset is too hard to ensure even by the most experienced driver under high concentration. To solve this problem, a feeler based guidance system following stubble with electro-mechanical servo is established. The system is utilized on the no-till wheat planter with the following results and conclusion though some experiments:1. It is the first research to utilize feeler based guidance system to improve linearity of planting operation in china. The guidance system is designed with the reference of standing maize straw or stubble in the field according to the environment and the operation request of no-till planting and the principle of no-till wheat planter following rows. The research is developed on the base of analysis detection method for agricultural vehicle and provided technological support for further improvement of wheat no-till planting quality following standing maize straw in stubble cover field.2. A unit of signal processing based on micro-chip controller is designed. It is composed of signal input channel (A/D transfer module), signal processor(micro-chip controller), signal output channel (D/ A transfer module) and wires, etc.3.A steering control system is designed on the base of hydraulic-electronic servo and feedback control with the components of signal receiver, steering force producer and transmitter, steering executor and feedback controller, etc.4. The parameter and performance test of the guidance system. The force that maize straw got and distributional linearity of straw has analysis. The relation diagram of input pulse number and steering angle of front wheel and function plot of two variables is got though measurement of relation between rotation angle of walking motor and front wheel. The relation coefficient of input pulse number and steering angle of front wheel is 0.9907 with the meaning of marked correlation between two parts. But intercept is -1.0728 from the regress equation which imply imitation line not go though the origin of coordinate and the deflection angle is 1.0728. The minus in the front imply there is a tardy angle with corresponding pulse number 287. The offset distance from detector for guidance signal to maize straw and the steering track are measured. Besides, the calculating method of steering angle and offset aredescribed.5. Steering track of tractor is measured during processing of rectifying tractor deviation based on the processing analysis. Then, the path plan of guidance system is made, and the program utilizing assemble language is compiled.6. JDT-654 made by Tian Jin tractor factory used as test platform. The simulating test is initially done in the field by the approach of bamboo simulating maize straw. The results of the test conclude that the guidance system utilizing the second path plan is feasible in the condition of 60mm offset distance and the rotation speed of 216r/min.