A method of controlling an electrical actuator of a mechanical system having a plurality of nested zones of contact, the method comprising the steps of: acquiring data about the mechanical system, which system includes a number of nested zones of contact; preparing a model of the system on the basis of said data and of a number of LuGre models put in parallel equal to the number of nested zones of contact, and determining parameters of the model and also a compensation structure for compensating friction in the nested zones of contact; including the compensation structure in a control relationship for the actuator A; and controlling the actuator by means of the control relationship.

An abnormality diagnosis apparatus includes: a friction identification unit that calculates a friction parameter that is a parameter used for calculation of frictional force of a power transmission mechanism connected to a motor; a model torque calculation unit that calculates model torque by performing a process of calculating an estimated value of torque of the motor by using a set value calculated in advance and the friction parameter; and an abnormality determination unit that diagnoses whether the power transmission mechanism is abnormal, on the basis of a result of comparison between the model torque and a motor torque detected by a motor torque detection unit.

A servo controller includes: a sinusoidal wave disturbance input unit for supplying a sinusoidal wave disturbance to a speed control loop including a speed command generator, a torque command generator and a speed detector; a frequency response calculator for estimating the gain and phase from the output of the speed control loop; a resonance frequency detector for detecting resonance frequencies at which the gain becomes maximum; a resonance mode characteristics analyzer for estimating resonance characteristics from the frequency response; and, a reference modal damping ratio retainer for retaining a reference modal damping ratio as a resonance characteristic corresponding to the reference lubricating condition, and the resonance mode characteristics analyzer calculates lubrication characteristics on the basis of the reference modal damping ratio and the measured modal damping ratio at the resonance frequency corresponding to the reference modal damping ratio.

A numerically controlled machine tool in which a numerical control program acquired from a reading and interpreting unit of a numerical control device is executed by a distribution interpolating unit and servo control units, to drive a feed shaft configured from a coarse movement mechanism and a fine movement mechanism, causing a tool to move relative to a workpiece, and thereby machining the workpiece, wherein the difference between a movement command for the feed shaft, and an output value which varies on the basis of said movement command is obtained, a movement command for the coarse movement mechanism is generated on the basis of said movement command, and a movement command for the fine movement mechanism is generated on the basis of said difference.

A method for identifying friction parameters for a linear module is disclosed. Since an acting interval of a friction is determined by a relative velocity between two contacting surfaces, and when the relative velocity is much greater than a Stribeck velocity, there is only a Coulomb friction and a viscous friction exist between the contacting surfaces, it is possible to use a measured torque signal of this interval to identify a Coulomb friction torque, a the linear module's friction torque, and the linear module's equivalent inertia. When the relative velocity between the two contacting surfaces is smaller than the Stribeck velocity, it is possible to identify a maximum static friction torque and the Stribeck velocity by referring to the three known parameters. Thereby, all the friction parameters can be identified within one reciprocating movement of the linear module, making the method highly feasible in practice.

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 method of controlling an electrical actuator of a mechanical system having a plurality of nested zones of contact, the method comprising the steps of: acquiring data about the mechanical system, which system includes a number of nested zones of contact; preparing a model of the system on the basis of said data and of a number of LuGre models put in parallel equal to the number of nested zones of contact, and determining parameters of the model and also a compensation structure for compensating friction in the nested zones of contact; including the compensation structure in a control relationship for the actuator A; and controlling the actuator by means of the control relationship.

The invention concerns a method for controlling a mechanism (10) displaying asymmetrical behaviour, the mechanism (10) comprising a first operating direction (F+) and a second operating direction (F−), the control method making it possible to generate, using a control module (24) of a computer (20), a control signal (x_com) from a setpoint signal (x_cons), in which—when the setpoint signal (x_cons) indicates that the mechanism (10) should be operated in the first direction (F+), the control module (24) applies a first corrector (100) to the setpoint signal (x_cons) in order to generate a control signal (x_com),—when the setpoint signal (x_cons) indicates that the mechanism (10) should be operated in the second direction (F−), the control module (24) applies a second corrector (100) to the setpoint signal (x_cons) in order to generate a control signal (x_com), and in which the first and second correctors (100, 200) have different parameters (Kp1, Kp2, Ti1, Ti2), in order to compensate for the asymmetrical behaviour of the mechanism (10).

The numerical control system includes: detecting circuitry to obtain cutting force generated in a machine tool; controlling circuitry to calculate a control amount according to a cutting condition and to control a feed drive mechanism of the machine tool; countermeasure determining circuitry to, when it is detected from the cutting force or a state of the feed drive mechanism of the machine tool that a machining defect has occurred, calculate a plurality of deviation degrees for possible causes of the machining defect, and compare the calculated deviation degrees and to thereby determine a cause of the machining defect whose occurrence has been detected; and correction-amount calculating circuitry to calculate, according to the cause of the machining defect determined by the countermeasure determining circuitry, a correction amount with respect to the control amount, and then output the correction amount to the controlling circuitry.

A method for processing operating data (e.g., position, setpoint, and pressure) for a valve assembly. The method is configured to associate characteristics of operation for the valve assembly with a root cause and/or a contributing factor. In one embodiment, the method can assign a first amplitude with a value that quantifies movement or jump of the valve stem that results from stick-slip on the valve assembly. The method can also assign a second amplitude with a value that quantifies a change in the data for the setpoint. The method can further ascertain the relationship or position of the first amplitude relative to the second amplitude, or vice versa. The method can use the relationship between the first amplitude and the second amplitude to indicate the root cause of the operation of the valve assembly.