Control method and device for modal test and modal test system

The invention relates to the technical field of modal testing, and discloses a control method for modal testing. The method comprises the following steps: obtaining a target test part of a target object detected by a recognition device; determining an initial position of a knocking part of the knocking device according to the target test part of the target object; and controlling an adjusting part of the knocking device to move a knocking part to an initial position, and controlling the knocking part to knock the target object. According to the application, the knocking part of the knocking device is used for applying the knocking operation meeting the modal test requirement to the target test part of the target object, so that the knocking device is used for replacing manual operation, the time and the physical power of test personnel can be saved, and the test efficiency is improved; in addition, in repeated knocking of the modal test, it can be guaranteed that each knocking position can be accurate and mee