Disclosed herein are embodiments related to safety in robotic systems. For example, an apparatus for collaborative robotics may include a first segment, a second segment, and a joint assembly. The joint assembly may include a processing device and a stepper motor, the stepper motor may control a relative position of the first and second segments, the processing device may perform closed-loop control of the stepper motor and monitor one or more performance metrics, and the processing device may cause braking of the stepper motor when a value of at least one of the performance metrics is outside an allowable range.

Disclosed herein are embodiments related to stepper motors in robotic systems. For example, an apparatus for collaborative robotics may include a first segment, a second segment, and a joint assembly. The joint assembly may include a stepper motor and a drivetrain to control a relative position of the first and second segments, and the drivetrain may have a gear ratio that is less than 30:1.

Disclosed herein are embodiments related to braking joints in robotic systems. For example, an apparatus for collaborative robotics may include a first segment, a second segment, and a joint assembly. The joint assembly may include a stepper motor to control a relative position of the first and second segments, and a phase of the stepper motor may be shorted when the apparatus is unpowered.

A method and system for determining geometric properties of a manipulator (2). The manipulator (2) is controlled to perform constrained motions exhibiting force interaction with the environment, or between different links of the manipulator (2), such that a kinematic chain is formed mechanically. The chain may include peripherals and external axes of motion. A constraining device, enables motions that facilitate the determination of geometric properties. A unified model of joint and link compliances facilitates determination of stiffness parameters. The force interaction is controlled with awareness of friction such that non-geometric properties are possible to identify, thereby enabling separation of non-geometric effects from the geometric ones, which improves accuracy.

Systems and a method for teaching a robot in reaching a given target location. The system and method include receiving inputs on a representation of a given target location to be reached by the robot. A check is made whether the given target location is singular. If the given target location is non-singular, the teaching of the robot is effected by associating with the given target location a selected configuration. If the given target is singular, the teaching of the robot is effected by associating with the given target location an assigned joint-values solution.

In an industrial robot, correction is made for change in position and attitude of an arm distal end due to mechanical deflection of the robot. In the robot, a moment applied to the first axis in its non-rotation direction opposite to its rotation direction is calculated from a load torque applied to the second axis in its rotation direction, a moment due to a second-axis-side self-weight, and a ratio of a distance between the rotation centers of the first and second axes, to a distance between the rotation centers of the second axis and a tool. A deflection amount indicating an angle of the first axis tilting in the non-rotation direction is calculated from the moment applied to the first axis and the rigidity of the first axis in the non-rotation direction. A control value is corrected based on the deflection amount to control the robot.

A robot control device includes the following: a main control unit; a servo control unit, which receives a position command c from the main control unit; and a bending correction block (24), which corrects the bending of the reduction gear connected to the servo motor. The bending correction block (24) includes the following: a first position-correction-value calculation means (63), which finds a first position-command correction value sgc based on the position command c; and a second position-command-correction-value calculation means (64), which finds a second position-command correction value skc based on the interference torque a. The servo control unit drives the servo motor based on a new position command obtained by adding the first position-command correction value sgc and the second position-command correction value skc to the position command c.

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.

According to one embodiment, a robot control device is used for a robot arm including a link and a motor for rotationally driving the link. The robot control device includes a derivation part. The derivation part derives a first estimated value including a variation of a rotation angle of the link and a second estimated value including a variation of a rotation angle of the motor, based on an angular velocity and a current reference value of the motor. Furthermore, the derivation part derives an external force generated to the robot arm, based on a difference between the first estimated value and the second estimated value.

A method of controlling a robot having a plurality of joints includes measuring load torque applied to a driving-force transmission system of each of the plurality of joints while moving a hand of the robot along a predetermined path, comparing a measurement value of the load torque and an allowable range of each of the joints, and controlling a rate of change in acceleration of the driving-force transmission system of each of the joints, depending on a comparison result, in a next operation in which the hand of the robot is moved along the predetermined path.