Method for the improved detection of the collision of a robot with its environment, system and computer program product implementing said method

A system for command of a robot comprising:

• a control member for the manipulation of the robot;
• an interface for the exchange of information regarding the state of the robot;
• and
• a processor for detecting collisions which is configured to execute a method for detecting a collision between a robot composed of a plurality of bodies linked together by at least one articulation and the environment of the robot, said method comprising:
• moving the at least one articulation of the robot by manipulating, via a motor of the robot, a torque applied to the at least one articulation of the robot,
• receiving, from a measurement device of the control member, at least a measure of a variable characteristic of the state of the robot among a position, a velocity or an acceleration of the at least one articulation of the robot,
• executing, with the processor, a computer program stored on a non-transitory computer readable medium, the computer program stored on the non-transitory computer readable medium including instructions that when executed by the processor cause the processor to automatically perform the steps of:
• generating, from a dynamic model of the robot, a signal representative of the collisions between the robot and the environment of the robot, said signal being called a residual r and comprising as many components as articulations of the robot,
• adaptive high-pass filtering of the residual r so as to render the residual r independent of parametric or non-parametric uncertainties related to low-frequency phenomena,
• determining recursively adaptive thresholds T composed of at least one first dynamic term TΔ1 dependent on the parametric uncertainties between said model and the real behavior of the robot, said parametric uncertainties being related to a first variable e1 characteristic of the state of said robot from among the following variables:
• the position, the velocity or the acceleration of the at least one articulation of the robot, or a linear or nonlinear function of one of these variables or of a combination of these variables, wherein determining recursively an adaptive threshold T of the adaptive thresholds T at a given instant is based upon a previously determined adaptive threshold of the adaptive thresholds T at an instant previous to the given instant, so that the adaptive threshold T is dependent on said parametric uncertainties between said model and the real behavior of the robot,
• comparing the filtered residual with the adaptive threshold T so as to deduce therefrom the existence or otherwise of the collision,
• deciding, as a result of the comparison of the filtered residual and the adaptive threshold T, if a collision between the robot and the environment of the robot occurs,
• providing the decision to the interface, and
• utilizing the decision provided to the interface, wherein
• the adaptive high-pass filtering is implemented via a recursive least squares algorithm and comprises:
• estimating, in a recursive manner, the coefficients of the transfer function of the high-pass filter G0−1, and
• filtering the residual r with the estimated high-pass filter.