We consider the problem of suppression of oscillations of a loaded flexible robotic “arm” that carries a load in the horizontal plane. It is required to find an optimal control force applied to the massive load of the “arm” that moves a mechanical system, within a given time period, from the initial state of rest to the new state of rest. A flexible robotic arm is considered, in an approximate model, as a set of three sequentially linked rods connected with each other and with the base by three spiral springs. First, the problem is solved via the Pontryagin maximum principle with minimization of the functional of the squared control force. Next, we pose the generalized Chebyshev problem based on the generalized Gauss principle. Calculations by these two methods are compared. The second method is shown as being superior to the first one.