Deflection amount estimation device, robot control device, and deflection amount estimation method

A deflection amount estimation device, comprising:

• a memory storing at least one program;
• and
• a processor configured to calculate, by executing the at least one program, an estimated deflection amount of a two-degree-of-freedom link structure portion including a plurality of rotation pairs of a robot arm in which a plurality of links including the link structure portion are connected by joints, wherein
• the processor executes:
• an opening angle calculation process of calculating an opening angle that is an angle formed by one link of the link structure portion pivoting about a reference axis which is an axis of one rotation pair of the link structure portion, and another link of the link structure portion pivoting about the reference axis;
• a load calculation process of calculating a load to which the link structure portion receives;
• a stiffness matrix determination process of determining, by using a stiffness value decision function representing a correlation between a stiffness value and the opening angle of the link structure portion, the stiffness value corresponding to the opening angle of the link structure portion calculated by the opening angle calculation process, the stiffness value being a value of each of components of a stiffness matrix that associates the load to which the link structure portion receives with the deflection amount of the link structure portion;
• and
• a deflection amount calculation process of calculating the deflection amount of the link structure portion based on the load which is calculated by the load calculation process and to which the link structure portion receives, and the stiffness matrix having the stiffness values determined by the stiffness matrix determination process as the components.

A deflection amount estimation method for detecting a deflection amount of a two-degree-of-freedom link structure portion including a plurality of rotation pairs of a robot arm in which a plurality of links including the link structure portion are connected by joints, comprising:

• calculating an opening angle that is an angle formed by one link of the link structure portion pivoting about a reference axis which is an axis of one rotation pair of the link structure portion, and another link of the link structure portion pivoting about the reference axis;
• calculating a load to which the link structure portion receives;
• determining, by using a stiffness value decision function representing a correlation between a stiffness value and the opening angle of the link structure portion, the stiffness value corresponding to the calculated opening angle of the link structure portion, the stiffness value being a value of each of components of a stiffness matrix that associates the load to which the link structure portion receives with the deflection amount of the link structure portion;
• and
• calculating the deflection amount of the link structure portion based on the calculated load to which the link structure portion receives and the stiffness matrix having the determined stiffness values as the components.