Detection method for suspension arm, controller, detection device for suspension arm and engineering machine

The embodiment of the invention provides a detection method for a suspension arm, a controller, a detection device for the suspension arm and an engineering machine. The detection method for a suspension arm comprises the steps of: obtaining a reference surface which is determined based on the positions of a plurality of detection points on a reference arm of the suspension arm; determining that the suspension arm is in a to-be-detected state; acquiring the position of a detection point at the top end of the suspension arm in the to-be-detected state; and determining the sidewise bending state of the suspension arm according to the position of the detection point at the top end and the reference surface. According to the embodiment of the invention, the trouble of manually calibrating the projection position can be saved, automatic reading and calculation in the measurement process are realized, the requirements on the personal technical level and experience of detection personnel are reduced, and the credibi