Research On Attitude Control System Of Kiwi Pollinator

Accurate pollination of kiwifruit is the technical bottleneck of industrial development.The stability of the pollination nozzle determines the amount of pollen and the pollination effect of the flower.The ground of the kiwi orchard is bumpy,causing the work platform to deviate,causing the pollination nozzle to fail to the target.The chassis attitude control is the key to improving the accuracy of pollination to the target.According to the chassis leveling requirements of targeted pollination operations,this paper designs the attitude adjustment structure of the double wishbone suspension according to the variation range of the chassis attitude of the pollinator in the field operations;the complementary fusion filtering algorithm is used to obtain the real-time attitude of the frame The dynamic motion calculation algorithm has constructed the chassis dynamic control system,and initially realized the dynamic leveling of the kiwi pollination platform.The main research contents are as follows:(1)The design of the posture adjustment chassis of the kiwi fruit pollinator.Based on the terrain parameters between the rows of the trellis kiwi orchard,the attitude adjustment range of the chassis control is clarified through calculation: the pitch angle adjustment range is ±6°,and the roll angle adjustment range is ±9°.The posture adjustment chassis suspension adopts an unequal-length double wishbone suspension,which uses an electric push rod to connect the frame and the suspension,and uses the extension of the electric push rod to drive the suspension to swing to achieve attitude adjustment.The structure is compact and stable,which can meet the design requirements.The chassis adopts mechanical transmission,which is realized by the motor,transmission,differential,transmission bridge and driving wheels;adopts the steering trapezoidal mechanism to steer;the chassis is designed as a wheeled motor driven remote control walking chassis,which is started by the driving motor and battery.(2)The design of the posture detection system for the frame of the pollinator.The frame of the kiwi pollinator is a rigid structure,and an attitude sensor is arranged in the center of the frame to obtain the real-time attitude of the chassis of the pollinator.This article uses the Arduino mega 2560 controller and the attitude sensor MPU6000 to obtain the frame attitude.Use IIC communication method to transmit the attitude data of MPU6000;use quaternion and complementary filtering fusion algorithm to describe attitude,correct angular velocity error,normalize acceleration value,correct gyroscope zero offset,quaternion update,normalization processing and use first-order Complementary filtering and fusion to obtain pitch,roll,and yaw frame attitude.On this basis,correct the sensor installation error and improve the measurement accuracy.(3)The design of chassis attitude adjustment control system.Complete the hardware circuit design and hardware selection and construction,and construct the pollinator attitude adjustment control system including the power supply module,the controller module,the attitude adjustment execution module,and the attitude remote control module.A center-point motion calculation algorithm is proposed.According to the positive or negative of the pitch angle and the roll angle,the motion amount of each putter is calculated in four cases.When adjusting the frame attitude,the center of the frame is the final movement target of each push rod,and the four push rods move at the same time.The PID double-loop control method is adopted.The attitude angle and angular velocity data measured by the sensor are used as input,the motor control quantity is output,and the PWM output is output.The wave controls the electric push rod to adjust the posture of the pollinator frame.The posture control algorithm system designed in this paper can effectively solve the virtual leg problem,with fast leveling speed and high real-time performance.(4)Prototype construction and test verification of attitude adjustment system.Build a chassis attitude control platform,which is composed of an adjustable chassis and an attitude adjustment control system.The chassis is composed of electric push rods,motors,transmission systems,steering systems,suspensions,and vehicle structures.Design static and dynamic attitude adjustment performance tests to verify the attitude adjustment effect of the chassis control system.Under the static environment of the pollinator,the attitude adjustment range of the roll angle of the vehicle body is-9.93～9.17°,and the attitude adjustment range of the pitch angle is-5.04～7.48°,which meets the requirements of ground ups and downs.When the pollinator is running at a speed of 0.5m/s,the frame tilt in the leveling control state fluctuates within 2°,and the stamens are within the effective spray coverage area,which can ensure sufficient pollination and meet the pollination requirements for the target.