Variable grounding control device, system and method for shielding layer, and engineering machine

The invention discloses a variable grounding control device, a variable grounding system and a variable grounding method for a shielding layer of an electric control system, and an engineering machine. The device comprises a receiver and a controller, wherein the receiver is used for receiving electromagnetic interference frequency coupled by the electric control system; and the controller is connected with the receiver, and is used for determining a grounding scheme of the shielding layer according to the electromagnetic interference frequency and an interference frequency threshold value, and outputting a group of switching value control signals which corresponds to the grounding scheme so as to control a group of grounding switches connected between the shielding layer and the ground. According to the technical scheme, the switch-off of the grounding switches can be adjusted in real time according to the field electromagnetic interference condition, and a variable grounding way is realized, so that the defect of difficulty in meeting the requirement of high interference resistance in a complicated and variable environment by adopting a single grounding way is overcome, and the interference resistance of the electric control system is improved.