Research on the Control System for the Conveying and Separation Experimental Platform of Tiger Nut Harvester Based on Sensing Technology and Control Algorithms

Enhancing the intelligence of Tiger nut harvesting equipment with the advancement of agricultural machinery is imperative. The conveying and separating device, a critical component of Tiger nut harvesters, faces efficiency issues due to mismatches between excavation feed rate and conveying separation capacities. A visualized Tiger nut harvesting device was designed to address this, incorporating parameters like conveying speed, torque, vibration frequency, and excavation depth. The device comprises a mechanical execution part and an automatic control system, the latter including modules for screw speed, torque, excitation frequency, and excavation depth control. Based on mechanical design analysis, control parameters and methods for each module were defined. An adaptive B-PID controller was proposed for trajectory tracking, combining backstepping and PID. A control model accounting for motion damping and error compensation was derived. Simulink simulations compared B-PID with backstepping controllers, showing B-PID's stable and effective trajectory tracking. Actual experiments assessed mechanical-control coordination using relative error metrics. The results showed that the maximum relative error of rotation speed was 3.8 %, the maximum relative error of frequency was 3.67 %, and the maximum relative error of excavation depth was 1.5 %. Correction models for excavation depth and excitation frequency parameters were established. This study can provide a theoretical basis and support for the intellectualization of Tiger nut harvesting machinery.