The invention relates to an object positioning system including: an actuator system and a measurement system. The actuator system comprises an actuator made of a material with predominantly electrostrictive properties and substantially no net polarization in absence of an electric field. The actuator system is configured to apply an electric field to the actuator, which electric field comprises a bias electric field and an actuation electric field superimposed on the bias electric field, a field strength of said actuation electric field being equal to or smaller than a field strength of the bias electric field. The measurement system is configured to measure an electrical property of the actuator which is representative for a mechanical state of the actuator. The measurement system comprises a bridge circuit including an actuator and a reference element having electrical properties matched to the electrical properties of the actuator.

A control apparatus for a vibration type actuator that moves a vibrating body in which vibrations are excited by an electromechanical energy conversion element, and a contact body contacting the vibrating body relative to each other includes a generation unit configured to generate multi-phase driving signals having a phase difference applied to the electromechanical energy conversion element, and a detection unit configured to detect an actual position of a movable unit including the vibrating body or the contact body. The generation unit sets the phase difference based on a deviation of the actual position from a target position of the movable unit. The generation unit makes larger a change rate of the phase difference against the deviation from when the movable unit stops to when the movable unit starts moving as the target position changes than that after the movable unit starts moving.

A method is disclosed for closed-loop motion control of an ultrasonic motor having at least one actuator with an excitation electrode and at least one common electrode, an element to be driven, a controller and at least one electrical generator for generating at least first and second excitation voltages U1 and U2 to be applied to the electrodes of the actuator for vibration of the actuator. A friction element of the actuator, due to its vibration, intermittently contacts the element to be driven with a driving force. The method includes providing the at least two excitation voltages U1 and U2 with different resemblance frequencies, a frequency difference deviating from a servo sampling frequency of the controller by 5 kHz at the most, and simultaneously applying the excitation voltages to the electrodes of the actuator.

Disclosed is a method and device for electrically activating an electromechanical element (8) for positioning an element to be driven which is in contact at least intermittently with the electromechanical element (8). By temporal sequence or by the successive execution of a static friction phase and a slip phase, the element to be driven performs a discrete drive step in a first drive direction, while by temporal sequence or successive execution of a slip phase and a static friction phase the element to be driven performs a discrete drive step in a second drive direction which is oriented contrary to the first drive direction. By appropriate repetition, a plurality of discrete drive steps and thus a large travel can be realized, which is limited in principle only by the extent or length of the element to be driven.

A control apparatus is capable of improving responsiveness in a minute movement of a vibration-type actuator that has a vibration body (a piezoelectric device and an elastic body) and a driven body that pressure contacts with the vibration body. A driving unit moves the driven body by causing a thrust-up vibration in a pressurizing direction and a conveyance vibration in a perpendicular direction in the vibration body by applying alternating voltages to the piezoelectric device. A control unit feedback-controls a position of the driven body by using a first operational parameter that defines an amplitude ratio of the conveyance vibration to the thrust-up vibration and a second operational parameter that defines amplitudes of the conveyance vibration and the thrust-up vibration. A correction unit corrects a control amount of the first or second operational parameter so as to increase as the amplitude ratio decreases.

The invention involves providing a reset signal before and or after one or more actuation signals to an electroactive polymer structure of an actuator. The reset signal can cause relaxation of defects such as e.g. trapped charge, dipoles and/or others in the EAP or EAP structure so that upon a subsequent activation using a drive signal, the initial actuation state is defined to be more constant than without use of the reset signal. Hence the actuation 5 output of a device employing the invention is more reproducible. The invention is applicable to actuator devices that have an electroactive polymer structure including an EAP material, where the structure is capable of providing a mechanical actuation upon subjection of at least part of the EAP material to an electrical drive signal.

A control device for a vibration-type actuator includes a control unit including first and second output units. The first output unit includes a first learned model subjected to machine learning in such a way as to output a first control amount for causing the contact body to relatively move with respect to the vibrator. The second output unit includes a second learned model subjected to machine learning in such a way as to output a second control amount, which is data of the same data format as that of the first control amount. The control unit updates parameters of the first learned model and parameters of the second learned model based on a control deviation, which is a difference between the first control amount and the second control amount output within the same sampling period as that of the first control amount.

The present invention relates to a linear drive, comprising: an actuator unit with at least one actuator; two guide elements and a movement element, wherein the movement element is displaceable along both guide elements by a movement generated by the actuator unit as a result of a stick-slip effect. In order to allow a more accurate displacement of the movement element in a compact design of the linear drive, according to the invention, the movement element can be brought into engagement with each of the two guide elements by means of static friction in order to be displaced along the two guide elements as a result of the stick-slip effect.

A short-travel nanoscale motion stage and a method for measuring thermally-related hysteresis data are provided. A stator unit of a left two-pole electromagnet and stator units of two inchworm motors are fixed on a right side surface of a left foundation frame, and an active unit of the left two-pole electromagnet and actives of the two inchworm motors are fixed on a left side surface of a stage moving component. An active unit of a right two-pole electromagnet is fixed on a right side surface of the stage moving component, while a stator unit of the right two-pole electromagnet is fixed on a left side surface of a right foundation frame. The stage moving component is fixedly mounted on a guide sleeve of an aerostatic guideway. Each of the stator units of the left and right two-pole electromagnets has an eddy current sensor and a hall sensor fixed therein.

The present disclosure relates to the technical field of mechanical precision manufacturing, in particular to a motor tracking error reduction method and an implementation device based on a micro-drive unit. A motor tracking error reduction method based on micro-drive unit includes: providing a motor mover as the working output end, and feeding back the position information of the motor mover to the micro-drive controller in real time by the sensor; controlling the micro-drive unit to compensate the displacement of the motor mover by the micro-drive controller; correcting the tracking error of the motor mover after the displacement compensation, and feeding back the tracking error information after correction to the motor controller. The error reduction method and implementation device in the present disclosure reduce the motor tracking error and solve the problem of coupling interference. In addition, the single position feedback is used to reduce the production cost.