Patent ID: 11897146
Assignee: CANON KABUSHIKI KAISHA
Field: Handling (Mechanical engineering)
Classification: CPC B  G | IPC B

Claim 0:
1. A control method for controlling a robot including at least two joints and configured to be controlled based on a predetermined path for executing a normal motion, the control method comprising:
acquiring an amplitude of a vibration at a natural frequency from a predetermined joint of the at least two joints while operating the robot in a way that the robot maintains the predetermined path and moves at a driving speed that causes the predetermined joint to vibrate at the natural frequency; and
acquiring a state of the predetermined joint based on the amplitude,
wherein the predetermined joint includes:
a rotational driving source;
a transmission configured to be driven by the rotational driving source;
an output side angle sensor configured to measure a rotational angle of a rotating shaft on an output side of the transmission; and
an input side angle sensor configured to measure a rotational angle of the rotating shaft of an input side of the transmission,

wherein the amplitude is acquired based on a difference between angle information output from the output side angle sensor and angle information output from the input side angle sensor,
wherein a fast Fourier transform (FFT) process is performed in a predetermined section divided in the angle information output from the output side angle sensor,
wherein the robot is operated so that the robot maintains the predetermined path and the driving speed becomes the driving speed at which the predetermined joint performs the vibration at the natural frequency by changing a command value of the predetermined joint in an operation to be performed during acquisition of the state in a time direction so that a driving amount of the predetermined joint in the predetermined path matches a driving amount of the predetermined joint in the operation when the state is acquired, and, wherein the command value of the predetermined joint is stretched in the time direction.