An analysis unit and method for determining at least one forming process characteristic of a servo press includes the steps of determining a torque profile of a motor of the servo press, wherein the torque profile belongs to a first cycle of the servo press and wherein the first cycle describes a forming process without an item to be processed by the servo press, determining a torque profile of the motor of the servo press, wherein the torque profile belongs to a second cycle of the servo press and wherein the second cycle describes a forming process with an item to be processed by the servo press, and comparing the torque profile belonging to the first cycle with the torque profile belonging to the second cycle to ascertain the at least one forming process characteristic.

A method for detecting a fault in a robot joint includes the steps of: performing a first torque measurement at the robot joint to thereby obtain a first set of torque values; calculating a first distribution characteristic reflecting a distribution of the first set of torque values; performing a second torque measurement at the robot joint to thereby obtain a second set of torque values; calculating a second distribution characteristic reflecting a distribution of the second set of torque values; and comparing the first and the second distribution characteristics to determine whether a fault is present or not. A difference in the distributions of torque measurements is a robust fault indicator that makes use of the repetitive behavior of the system.

A method for measuring an axial-force of a bolt fastened to a component to be fastened, includes temporarily fastening the bolt to the component to be fastened with a temporarily-tightening torque, the temporarily-tightening torque being a torque which is determined in advance and by which a depression is formed on a head of the bolt, measuring a first axial force of the temporarily-fastened bolt, regularly fastening the bolt to the component to be fastened with a regularly-tightening torque, the regularly-tightening torque being torque which is determined in advance and larger than the temporarily-tightening torque, measuring a second axial force of the regularly-fastened bolt, and measuring an estimated axial force of the regularly-fastened bolt by using the torque with which the bolt is temporarily fastened, the torque with which the bolt is regularly fastened, and a difference between the first and second axial forces.

A method for monitoring at least one machine tool (12) featuring the steps (a) real-time detection of time-dependent measurement data (M.sub.i) characterising a production process running on the machine tool (12), (b) provision of the measurement data (M.sub.i) with a time stamp which encodes a time (t.sub.j) at which a respective measurement data (Mi) was detected, such that measurement results (M.sub.i(t.sub.j)) are obtained, (c) transmission of the measurement results (M.sub.i(t.sub.j)) via a non-real-time-capable data bus (26) to an evaluation unit (28), (d) calculation of at least one command (B) from the measurement results by means of the evaluation unit, (e) transmission of the at least one command (B) via the data bus (26) and (f) monitoring of the production process in real-time by means of a programme that contains the command (B).

There is provided a method for supporting work of improving the design of a mechanical apparatus which is operated by a motor, including: an operating step of operating a movable section of the mechanical apparatus by the motor; a measuring step of obtaining at least one index which indicates an input into the motor or an output from the motor in the operating step; a determining step of determining the mechanical properties of the mechanical apparatus, by using at least one index obtained in the measuring step; and a specifying step of specifying at least one improvement-required item which is required to be improved in the design of the mechanical apparatus, by using the mechanical properties determined in the determining step.

Motion control of a robot arm is performed via a reducer connected to a motor. A controller thereof includes a thrust control unit that generates motor position command value based on an input thrust command value, and a motor control unit that generates a current value based on the motor position command value. The motor control unit feeds back a motor position detected by a motor encoder, and the thrust control unit feeds back thrust detected by a thrust meter. The feedback from the motor control unit suppresses vibration phenomena at the reducer, and the feedback from the thrust control unit suppresses transmission error, thereby enabling motion control of the arm with rapidity and precision.

A torque control apparatus includes a torque command output unit including a first low pass filter configured to cut off a torque command value by a first frequency, and a switching unit configured to switch, when a first torque value detected by a first torque sensor satisfies a predetermined condition, a second torque value detected by a second torque sensor to the torque command output unit. The switching unit includes a second low pass filter configured to cut off the second torque value by a second frequency which is higher than the first frequency and output the obtained value to the torque command output unit, uses the second low pass filter for a predetermined period of time after the switching, and outputs the second torque value to the torque command output unit without using the second low pass filter after the predetermined period of time has passed.

A control method according to an aspect of the invention includes a process for setting target fastening torque, a pulse interval of neighboring pulses, and an elevated value of torque per pulse, detecting last fastening torque at an Nth pulse (N is a natural number of 1 or more) after seating of a fastening member, setting pulse loading time at an N+1th pulse and pulse strength at the N+1th pulse based on the last fastening torque at the Nth pulse so that fastening torque at the N+1th pulse coincides with a multiple of the elevated value, controlling a fastening tool based on the pulse interval, the pulse loading time, and the pulse strength so that last fastening torque at an N+Mth pulse (M is a natural number of 1 or more) reaches target fastening torque.

Motion control of a robot arm is performed via a reducer connected to a motor. A controller thereof includes a thrust control unit that generates motor position command value based on an input thrust command value, and a motor control unit that generates a current value based on the motor position command value. The motor control unit feeds back a motor position detected by a motor encoder, and the thrust control unit feeds back thrust detected by a thrust meter. The feedback from the motor control unit suppresses vibration phenomena at the reducer, and the feedback from the thrust control unit suppresses transmission error, thereby enabling motion control of the arm with rapidity and precision.

A torque control apparatus includes a torque command output unit including a first low pass filter configured to cut off a torque command value by a first frequency, and a switching unit configured to switch, when a first torque value detected by a first torque sensor satisfies a predetermined condition, a second torque value detected by a second torque sensor to the torque command output unit. The switching unit includes a second low pass filter configured to cut off the second torque value by a second frequency which is higher than the first frequency and output the obtained value to the torque command output unit, uses the second low pass filter for a predetermined period of time after the switching, and outputs the second torque value to the torque command output unit without using the second low pass filter after the predetermined period of time has passed.