1. An apparatus configured to measure friction created by an object, the apparatus comprising: a set of three-dimensional force sensors, distributed on a face of a support, each sensor being configured to output electrical signals representative of a force applied by the object on this sensor, the object moving with respect to the set of sensors or vice versa; and electronic means for processing signals output by the sensors, these electronic processing means determining components of forces applied on the sensors by the object, wherein the electronic processing means also output relative tangential velocities of points of the object that are in contact with the set of sensors, by making a space-time analysis of the signals emitted by the sensors.