Influence of screw blades on the performance of a screw-drive granary robot

A granary robot with screw-drive mechanisms can perfectly adapt to a loose grain terrain. The design of the helical wheels is significant for the driving performance of this robot. Because this robot moves due to the action of the blade on the grain, the parameters of the helical blade are especially important among all factors. Therefore, to determine the effect of blades on the performance of a screw-drive granary robot, a screw robot-corn coupling model is established based on the coupling of the discrete element method and multibody dynamics. The model can analyze the interaction of the screw wheel with the grain particles. Then a robot with two helical wheels is designed, manufactured, and tested to verify the accuracy of the coupling model. The cosimulation created with this model has good accuracy compared with the experiment, and the mean relative errors of sinkage, velocity, and slip ratio are 3.43%, 1.21%, and 13.87%, respectively. Finally, the effects of the height, axial length, helix angle, and number of screw blades on the driving performance of the robot are studied with single-factor simulations. The trends of the torque, slip, and drawbar efficiency varying with these parameters of the screw blade are obtained, which can provide critical insights for the preliminary design of a screwed granary robot.