Universal Robots

Abstract The invention relates to a method for monitoring a robot system comprising a robot arm and a peripheral device, the method comprising the steps of: providing a communicative peripheral connection between the peripheral device and a robot controller; establishing an operation signal history in a digital storage wherein the operation signal history is based on operation representations; executing a robot operation process on the robot controller; establishing a peripheral signal associated with the peripheral connection; recording the peripheral signal to obtain a peripheral signal representation; updating the operation signal history by providing the peripheral signal representation as an operation representation of the operation representations; and tracking operation of the robot system based on the operation signal history. The invention further relates to a robot system.

Abstract A strain wave gear includes an outer ring and an inner ring rotatably arranged in the outer ring. The inner ring includes an internally toothed gear and a flex spline is arranged in the inner ring and includes a flexible part that includes an external toothed gear. A wave generator is rotatable in relation to the flex spline and is configured to flex the flexible part in a radial direction to partly mesh the external toothed gear with the internally toothed gear causing rotation of the inner ring in relation to the outer ring. A part of the inner ring extends out of the outer ring and includes an outwardly protruding output flange. An encoder reader can be disposed on the outer ring and an encoder track can disposed on the inner ring. A robot joint that includes the strain wave gear is also disclosed.

Abstract The invention relates to a robot controller controlling a robot arm, the robot controller is configured to maintain the robot arm in a static posture when only gravity is acting on the robot arm and allow change in posture of the robot arm when an external force different from gravity is applied to the robot arm. The free-drive mode of operation is activatable by a user establishing a free-drive activation signal to the robot controller, which then is configured to:—monitor a value of at least one joint sensor parameter;—compare the value of the mode of joint sensor parameter to a maintain free-drive joint sensor parameter threshold value;—maintain the robot arm in said free-drive mode of operation for a predetermined maintain free-drive period of time; and—leave the free-drive mode of operation if the value of the joint sensor parameter does not exceed the maintain free-drive joint sensor parameter threshold value within the maintain free-drive period of time.

Abstract The invention relates to a robot controller controlling a robot arm, the robot controller is configured to maintain the robot arm in a static posture when only gravity is acting on the robot arm and allow change in posture of the robot arm when an external force different from gravity is applied to the robot arm. The free-drive mode of operation is activatable by a user establishing a free-drive activation signal to the robot controller, which then is configured to initiate a free-drive mode activation sequence including the steps of: in a predetermined activation sequence period of time monitor a value of at least one joint sensor parameter, and compare this value to a free-drive activation joint sensor parameter threshold value. The robot controller is configured to switch to the free-drive mode of operation if the at least one value does not exceed the free-drive activation joint sensor parameter threshold value within the predetermined activation sequence period of time.

Abstract A method of detecting change in contact between a contact part of a robot arm and an object as defined by the independent claims, by obtaining a contact force provided at the contact part of the robot arm by sensing a force provided to a part of said robot arm; and by obtaining the part acceleration 5 of the contact part of the robot arm by sensing the acceleration of at least a part of the robot arm and then indicate if a change in contact between the contact part of the robot arm and the object has occurred based on the obtained contact force and the obtained contact part.

Abstract 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.

Abstract A robot controller for controlling a robot arm includes a first space shaping module configured to provide a shaped first space target motion by convolving a first space target motion with an impulse train, where the first space target motion defines a target motion in a first reference space; a second space shaping module configured to provide a shaped second space target motion by convolving a second target motion with the impulse train; where the second target motion defines the target motion in a second reference space; and a motor controller module to generate motor control signals to the joint motors based on the shaped first space target motion and the shaped second space target motion.

Abstract A method of obtaining the gear stiffness of a robot joint gear of a robot joint of a robot arm, where the robot joint is connectable to at least another robot joint. The robot joint comprises a joint motor having a motor axle configured to rotate an output axle via the robot joint gear. The method comprises the steps of: —applying a motor torque to the motor axle using the joint motor; —obtaining the angular position of the motor axle; —obtaining the angular position of the output axle; —determining the gear stiffness based on at least the angular position of the motor axle, the angular position of the output axle and a dynamic model of the robot arm.