Electric and hydraulic control method for positive flow system and application of electric and hydraulic control method to hydraulic grab

The invention discloses an electric and hydraulic control method for a positive flow system and belongs to the field of electric and hydraulic control systems. The method includes the following steps that firstly, when a controller detects an acting load, needed flow parameters and relationship coefficients are calculated; secondly, according to the difference of the flow parameters, different handle coefficients are acquired; thirdly, according to the differences of the flow parameters and the relationship coefficients, the current of an electric proportional decompression valve of a main pump is acquired, and the displacement of the main pump is adjusted according to the current. The invention further provides application of the electric and hydraulic control method to a hydraulic grab. According to electric signals of electric proportional handles, the electric proportional decompression valve of the main pump is controlled, and any action is completely matched with the adjusting power of the pump. By the adoption of the method, through positive flow control and adjustment of a positive control pump and an electric and hydraulic multi-way valve, the power of the pump and the power of an engine are completely matched in real time, the power of the load and the power of the pump are completely matched in real time, the system is free of throttling loss and overflow loss, emitted heat of the system is reduced, fuel consumption is reduced, hysteresis is avoided, and the responding speed is high.