Swing control system

A slewing control system has a structure that an electro-hydraulic proportional pressure relief valve oil inlet is connected with a guiding pipe, and an oil outlet is connected with a two-position reversing valve oil inlet. The first oil outlet of the manual operation valve is connected with the first oil inlet of a third shuttle valve through the first pipeline. The second inlet of the third shuttle valve is connected with the right oil outlet of the two-position reversing valve, the oil outlet is connected with the second control oil outlet of three-position reversing valve. The second oil outlet of manual operation valve is connected with the first oil inlet of the second shuttle valve through the second pipeline. The second inlet of the second shuttle valve is connected with the left oil outlet of the three-position reversing valve, the oil outlet is connected with the first control oil outlet of three-position reversing valve. Both oil inlets of the first shuttle valve connect with the first pipeline and the second pipeline respectively, the oil outlet is connected with the first oil inlet of the fourth shuttle valve. The second oil inlet of the fourth shuttle valve is connected with the oil outlet of the electro-hydraulic proportional pressure relief valve, the oil outlet is connected with the oil inlet of the braking cylinder. Manual control mode and automatic control mode can be implemented simultaneously or singularly, operational efficiency also can be improved.