This novel solution is a single degree-of-freedom high-ﬁdelity haptic device. The invention is based on the combination of two different actuators: one intended to supply the main couple with permanent regime and the second only supplying transitory couples. The main couple depends on the speed of the main engine. Because the latter is speed-compensated, its inertia is not transmitted to the load. Furthermore, the precision is insured by the auxiliary engine which is highly dynamic thanks to its low moment of inertia. The main advantage of this architecture is to be able to supply couples in a very wide range (from 3 to 4 orders of magnitude), with a very fine precision that surpasses the capacities of all the known electromechanic actuators. Classic interfaces only give haptic feedback on two orders of magnitude, between 0.1 N and some Newtons. This novel interface allows a haptic feedback 10 times superior to all other interfaces (3 orders of magnitude instead of 2). So, it applies perfectly to the felt of microscopic effort which dynamics and variability are very important. Only this interface can allow to interact in a transparency way with the microworld today.