Control of power-shuttle motion-inverter

The topic of this paper is the design of the control system for the automatic motion-inverter in agricultural tractors. The objective of this system is to perform a fully automated symmetric motion inversion The device (reverser) used for the automatic motion inversion is an electro-hydraulic system, constituted by two clutches (one for the forward, and one for the reverse motion), driven by a Proportional Electrohydraulic Valve (EVP) and by an on-off Directional Electrohydraulic Valve (EVD). The measured variables are the input/output rotational speeds of the reverser. All the subtasks of the reverser control systems are considered: the design of an inner-loop for the EVP, the open-loop switching strategies, and the design and analysis of the outer control loop which regulates the vehicle speed during the motion-inversion.