Mobile robot having friction coefficient estimation function and friction coefficient estimation method

A friction coefficient estimation method comprising:

• estimating contact angles between wheels of a mobile robot and a ground and uncertainties associated with the contact angles;
• detecting joint poses of the mobile robot and state variables of the wheels;
• estimating traction forces applied to the wheels using the state variables of the wheels;
• estimating uncertainties associated with the traction forces;
• estimating normal forces applied to the wheels using the contact angles, the contact angle uncertainties, the joint poses, the traction forces, and the traction force uncertainties;
• estimating uncertainties associated with the normal forces;
• estimating friction coefficients between the wheels and the ground using the traction forces and the normal forces;
• estimating uncertainties associated with the friction coefficients using the traction forces, the traction force uncertainties, the normal forces, the normal force uncertainties, and the friction coefficients;
• and
• determining a maximum friction coefficient from among the friction coefficients such that the maximum friction coefficient has an associated one of the friction coefficient uncertainties that is less than a threshold and at a point of time when the torque applied to the wheels changes from an increasing state to a decreasing state.

A mobile robot configured to move on a ground, the mobile robot comprising:

• a moving unit configured to move the mobile robot with respect to the ground, the moving unit including wheels that are configured to transport the mobile robot through rotation thereof;
• and
• a controller configured to control a rate of acceleration and deceleration of the moving of the mobile robot based on a maximum friction coefficient between the wheels and the ground by,
• estimating friction coefficients between the wheels and the ground and uncertainties associated therewith based on estimated traction forces and normal forces applied to the wheels,
• selecting a plurality of the estimated friction coefficients whose corresponding uncertainties are less than a threshold, and
• selecting as the maximum friction coefficient the estimated friction coefficient that corresponds to a time when a torque applied to the wheels changes from an increasing state to a decreasing state.