Robot and robot control method

摘要

Provided are a robot and a robot control method in which highly accurate positioning of a link is enabled without losing flexibility of a joint.

主权项

1. A robot comprising:
a link that rotates around a joint that serves as an axis; a first string-shaped member and a second string-shaped member connected to the link and arranged in an antagonistic manner; a drive unit that includes a first actuator that generates driving force for advancing and retreating the first string-shaped member and a second actuator that generates driving force for advancing and retreating the second string-shaped member, the drive unit generating torque around the joint and stiffness of the joint based on the driving force of the first actuator and the driving force of the second actuator; and a control device that controls the driving force generated by the first actuator and the second actuator, the control device comprising:
a position control unit that calculates a torque command value around the joint based on angular deviation of a joint angle relative to a reference joint angle received from outside of the robot;a tensional force minimum value calculation unit that obtains a natural frequency of each string-shaped member satisfying fn>fmin>fc, fmin indicating the natural frequency, fc indicating a control bandwidth of the position control unit, fn indicating a Nyquist frequency of the position control unit, and
the tensional force minimum value calculation unit calculates a tensional force minimum value of the first string-shaped member and the second string-shaped member from a relational expression Tmin=4×L2×μ×fmin2,L indicating length of the first string-shaped member and the second string-shaped member, μ indicating linear mass density of the first string-shaped member and the second string-shaped member, and Tmin indicating the tensional force minimum value;a driving force command value calculation unit that calculates driving force command values of the first actuator and the second actuator by using the tensional force minimum value, the joint angle and the torque command value so that tensional force of one of the first string-shaped member and the second string-shaped member with the smaller tensional force coincides with the tensional force minimum value; anda drive control unit that generates, on the first actuator and the second actuator, driving force corresponding to the driving force command values obtained by the driving force command value calculation unit.