Development of a DSP-based electronic control system for the active spray boom suspension

Abstract

When sprayer is in field operation, the entire boom needs to maintain an ideal height with the ground or crop canopy, which can maximize the quality of pesticide application and minimize the negative effect of application on the environment. This paper introduces a design of high-performance boom control system for pendulum active suspension. The system consists of a human machine interface (HMI) and a real-time controller based on DSP microprocessor. Three different control modes, roll control mode, wing height control mode and hybrid control mode, have been developed to meet the needs of different operators. Considering the irregularity of field ground and the inconsistency of crop canopy height, a signal processing and data fusion algorithm was designed. The DSP-based control system is assembled on a 28 m boom with the pendulum suspension, and the step response and sinusoidal tracking tests of the active boom control system are carried out by using a six-degree-of-freedom motion platform. Firstly, the influence of different control parameters on the control performance was tested, and then three different control modes of the control system are tested and compared, for a given 0.1 Hz sine/cosine test signal, the accuracy of boom roll control mode was 90.27%, the accuracy of wing height control mode was 93.0%. The step response test of hybrid control system was carried out, the height difference between the left wing and the right wing decreases to less than 10% of the initial disturbance within 2.35 s, while the roll control system needs 5.71 s, the response time was shortened by 58.84%. Field test results show that under the roll control system, the maximum roll angle of the boom was only 0.841°, and the maximum roll angle of the chassis was 4.041°. The results show that the DSP-based control system can effectively control the movement of the boom and meet the requirements of field use, also the effectiveness of signal processing algorithm and control method has also been verified.