This paper describes the experimental validation of an hybrid actuator built up by a four-bar mechanism of crank-rocker type, with the motorized crank driven by an electric cam. The characteristics of the machine and the motor have required a special effort in order to tune up a responsive control system. The motion control has been performed in two indipendent ways, with a PC- based control that combines a P-I regulator and a feed- forward control and with a custom P-I-D regulator on a DSP board. During test sessions, the dynamic stress produced on a flexible machine ground link is acquired with accelerometers. Results show the obtained vibration reduction and the corresponding functional limitations, like maximum acceleration increase. The use of two different control devices with a common asynchronous vectorial motor ensures the achieved results can be considered significant for a wide range of industrial applications.