Electric control hydraulic steering system and crane

According to the electrically-controlled hydraulic steering system and the crane, the oil pressure applied to the two ends of a valve element of a proportional valve is changed by changing the current of a hydraulic proportional pilot control proportional valve coil, and the valve element of the proportional valve is pushed to move through the oil pressure; the two modes of post-valve feedback and post-pump feedback are parallel, so that the response characteristic of the system is increased, the response time is shortened, and the feedback reliability is improved; the displacement sensor is additionally arranged in the proportional valve to monitor the displacement of the valve element of the proportional valve, the flow of the proportional valve is controlled by controlling the position of the valve element of the proportional valve, the control precision of the proportional valve is higher, the control method of the proportional valve can adopt valve element displacement feedback control or coil current fe