A method of controlling a robot arm with robot joints, where the joint motors of the joints are controlled based on a signal generated based on the friction torque (formula I) of at least one of the input/outside of the robot joint transmission and the robot joint transmission torque (formula II) between the input side and the output side of the transmission. The friction torque is determined based on: at least two of the angular position of the motor axle; the angular position of the output axle and/or the motor torque provided to the motor axle by the joint motor. The robot joint transmission torque is determined based on: at least one of the angular position of the output axle; the angular position of the output axle and/or the angular position of the motor axle; the angular position of the motor axle and the motor torque provided to the motor axle by the joint motor.

A system and method for reducing mechanical oscillations in a multi-axis control system provides a first command for a dynamic notch filter at a first update rate to multiple motor drives. Each motor drive is operatively connected to a motor for an axis in the multi-axis control system. Each motor drive receives a second command for desired operation of the motor at a second update rate. Operation of the dynamic notch filter in each motor drive is changed as a function of the first command at the first update rate, and each motor drive generates a desired output voltage for desired operation of the motor at a third update rate. The third update rate is faster than the second update rate, the second command is passed through the dynamic notch filter to generate a filtered command, and the desired output voltage is generated as a function of the filtered command.

A method and robot controller configured to obtain an inertia-vibration model of the robot arm. The inertia-vibration model defines a relationship between the inertia of the robot arm and the vibrational properties of said robot arm and have been by setting the robot arm in a plurality of different physical configurations and for each of said physical configurations of said robot arm obtaining the vibrational properties and the inertia the robot arm. The inertia-vibration model makes it possible to in a simple and efficient way to obtain the vibrational properties of different physical configurations of the robot arm whereby the robot arm can be controlled according to the vibrational properties of the robot arm. This makes it possible to reduce the vibrations of the robot arm during movement of the robot arm.

A system and method for reducing mechanical oscillations in a multi-axis control system provides a first command for a dynamic notch filter at a first update rate to at least one motor drive. Each motor drive is connected to a motor for an axis in the multi-axis control system. Each motor drive receives a second command for desired operation of the motor at a second update rate. Operation of the dynamic notch filter in each motor drive is changed as a function of the first command at the first update rate, and each motor drive generates a desired output voltage for operation of the motor at a third update rate. The third update rate is faster than the second update rate, the second command is passed through the dynamic notch filter to generate a filtered command, and the desired output voltage is generated as a function of the filtered command.

Provided is a robot control device capable of reducing a robot vibration amount using machine learning based on a small number of operations. A robot control device according to one aspect of the present invention that, in order to perform a task in relation to a target object which is made to move by a robot, controls operation by the robot based on an operation program that uses a plurality of pass-through points to specify a movement path that includes one or more task sections in which the task is to be performed, the robot control device including: a command value generation unit configured to, based on the operation program, generates a command value that instructs a state of the robot for each time; a driving unit configured to drive the robot in accordance with the command value; a vibration amount obtainment unit configured to, for each time, obtain an amount of vibration of the robot that is driven by the driving unit; a vibration amount extraction unit configured to, based on the operation program, extract the amount of vibration for a time corresponding to the task section from among the amounts of vibration obtained by the vibration amount obtainment unit; and a command value correction unit configured to, based on the amount of vibration extracted by the vibration amount extraction unit, correct the command value.

A drive unit for a robot, having an input shaft, an input shaft drive motor and a strain wave gear mechanism for transmission to an output shaft. The strain wave gear mechanism has a wave generator which is operatively connected to the input shaft, a flexible ring and a toothed ring are connectable to the output shaft, a first sensor for detecting an angular position of the input shaft and a second sensor for detecting the angular position of the output shaft. In order to allow the drive unit to precisely adjust the angular position of the output shaft to each setpoint angular position, the drive unit has a third sensor for detecting an expansion of the flexible ring. A robot having such a drive unit and a method for precisely adjusting the angular position of the output shaft are also provided.

A spring constant correction device and method measure a position and attitude of a distal end of an articulated robot when the articulated robot is operated in a state where elastic deformation is compensated, compare measurement values of the position and attitude of the distal end and target values of the position and attitude, and correct a spring constant based on a result of the comparison. In case of the correction, the spring constant is corrected at a predetermined position based on at least three of: an angle of an end point attitude based on the measured attitude; a torque of the distal end in the end point attitude; an angle of the distal end in a target attitude; and a torque of the distal end in the target attitude. A program of such a method is recorded in a recording medium.