Method for updating a collision detection algorithm in a self-propelled robotic tool

Abstract

The present disclosure relates to a self-propelled robotic work tool (), e.g. an automatic robotic lawn mower, and a corresponding method. The robotic tool comprises an inertia measurement unit (IMU) which generally obtains () measured IMU parameters regarding the robotic working tool's movement. A prediction algorithm () predicts () required motor currents for driving the robotic work tool's wheels () based on the measured IMU parameters. The predicted motor current is compared () to the actual current used and the difference constitutes an error (), which is used in a collision detection unit (). If the collision detection unit () senses that the actually used motor current is much higher than the predicted current, a collision may be indicated (). The prediction algorithm is repeatedly updated based on the error () by incrementing or decrementing an error category counter (error cat,) if the error () is above or bellow a first or second threshold (), and increasing or decreasing a prediction algorithm setting (), e.g. a motor current offset term i offset—if the error category counter (error cat,) is above or bellow a third or fourth threshold (). This allows the prediction algorithm to adapt to circumstances where the robotic tool is used. For instance, if a lawn mower operates in thick grass, the prediction algorithm can be adapted not to detect false collisions due to increased motor current values.