Search

Precision micro-manipulation tasks demand high-speed motion but low driving frequency for stick-slip actuators to achieve efficient operation and reduce friction wear. This paper presents a novel parasitic-type linear stick-slip actuator with macro fiber composites (MFCs). Unlike conventional piezoelectric actuators, the proposed stick-slip actuator has large single-step displacements and high motion consistency. It can realize high-speed motion under low driving frequency due to the superior properties of MFCs and the dual-drive method with a single driving foot. The actuator is devised based on a multi-beam-compliant driving mechanism, a pair of MFCs, and a slider. Also, an electromechanical dynamic model is proposed. A switching control strategy guarantees high positioning accuracy under large strokes. Finally, an experimental system is built. The single-step displacement can reach 367.7 μm with the dual-drive method. The actuator still has an effective stepping displacement of 63.4 μm even with a load of 2.1 kg. The maximal speed is 131.80 mm/s at a working frequency of 450 Hz. Thus, the actuator can realize mm/s motion with several Hertz driving voltages. Moreover, the maximum forward-reverse deviation only accounts for 1.31 % for a 2504 μm motion range, and the closed-loop motion resolution is 1.970 nm. Experiments verify the effectiveness and performance of the designed MFC stick-slip actuator. [Display omitted] • Macro-fiber-composite stick-slip actuator with large single-step displacements. • High forward-reverse motion consistency. • Electromechanical dynamic model for the MFC stick-slip actuator. • Nanoscale motion resolution using feedback control. [ABSTRACT FROM AUTHOR]

In this study, a novel bionic piezoelectric stick-slip actuator inspired by human body is proposed, fabricated and tested. The working principle of this actuator mimics the bending movement of human body. A PZT stack is embedded in the flexible stator through a flexure hinge mechanism. The elongation of the PZT stack is transferred to the driving head, producing an oblique displacement. The vertical and horizontal components are used to press and actuate the slider, respectively. The proposed piezoelectric actuator is designed by simulation method, and then the structural sizes of the flexible stator are determined accordingly. The dynamics simulation is used to analyze the motion characteristics of the actuator, which further reveals the working principle. Finally, a prototype of the proposed actuator is developed and its output characteristics are tested by experiments. The experimental results show that the maximum output velocity of the developed actuator is 19.33 mm/s at a voltage of 100 V and a frequency of 600 Hz. The maximum output force is 1.8 N under a preload force of 2 N. These results indicate the feasibility and advantage of the proposed piezoelectric stick-slip actuator inspired by human body in this work. [Display omitted] • A new bionic piezoelectric stick-slip actuator inspired by bending motion of human body is proposed. • The working principle of this proposal is revealed and validated by simulation and experimental methods. • The developed prototype obtained a high output velocity of 19.33 mm/s under the voltage of 100 V. [ABSTRACT FROM AUTHOR]

The backward motion is an intrinsic feature of the conventional piezoelectric stick-slip actuator (PSSA), limiting the output speed and applications. Various methods have been proposed for restraining the backward motion. Each method has its pros and cons for the practical application of driving a precision motion stage. A novel method for restraining the backward motion is proposed in this article, in which a passive damping foot is utilized to hold the runner when the active driving foot slips on the runner. An actuator is developed based on this mechanism. The structural dimensions of the actuator are determined with an analytic model and a finite element model. A prototype of the proposed actuator is fabricated and tested by experiments. The experiments validate the operating principle of the actuator for restraining the backward motion, which is eliminated (the backward ratio is less than 1%) when the passive damping foot has an appropriate clamping force. The proposed method is very valuable for designing a PSSA with no backward motion, and it can broaden the applications for precision manipulations. [ABSTRACT FROM AUTHOR]

A stick-slip piezoelectric actuator with bidirectional motion is proposed and measured, which uses coupled asymmetrical flexure hinge mechanisms and symmetrical indenter to generate controllable tangential displacement. The operating principle of the proposed stick-slip actuator is illustrated, and the normal force variation between the stator and slider is analyzed. A dynamic model based on the method of dimensionality reduction is established to simulate the displacement and load capacity. In order to obtain improved actuator properties, the design rules of the coupled flexure hinge mechanisms are discussed, and the tangential and normal displacements of the indenter are investigated by the finite element method. A prototype is fabricated, and the experiment investigation of the actuator characteristics is presented. Testing results indicate that the actuator achieves the maximum output velocity of 10.14 mm/s and its maximum load reaches 1.5 N under a voltage of 100 Vp–p and a frequency of 850 Hz in the positive x -direction. The maximum efficiency of the actuator is 0.57% with a load of 90 g, a locking force of 5 N, and the actuated velocity of 5.48 mm/s. In addition, experimental results confirm the feasibility of the presented model by comparing numerical simulation results. [ABSTRACT FROM AUTHOR]

Copyright of Piezoelectrics & Acoustooptics is the property of Piezoelectric & Acoustooptic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A symmetrical hybrid driving waveform (SHDW) is proposed in this paper, which includes a symmetrical saw-tooth driving waveform and a sinusoidal friction regulation waveform, and the sinusoidal friction regulation waveform is applied to the shrinkage period of the symmetrical saw-tooth driving waveform. In other words, the proposed SHDW can be achieved when the waveform symmetry of the hybrid driving method is 50%. The SHDW can effectively drive the designed symmetrical linear piezoelectric stickslip actuator, and the motion direction is also easily regulated. The excitation principle of the actuator excited by the SHDW is explained in detail. A prototype is fabricated and the experimental investigations of the actuator characteristics are carried on. The higher velocity and the larger driving capacity are realized using by the SHDW relative to the asymmetrical hybrid driving waveform. Testing results show that the prototype excited by the SHDW can obtain the peak no-load speeds of 0.41 and 0.39 mm/s in the forward and reverse directions when the saw-tooth driving waveform voltage is 10 Vp-p for 800 Hz and the sinusoidal friction regulation waveform voltage is 2 Vp-p for 39 kHz. The step efficiencies can reach 92% and 90%. The driving capacities can reach 10.52 and 9.85 [(mm/s)g/mW] with the load of 70 g under the locking force of 0.1 N. The actuator excited by the SHDW will make it ideal for miniature information technology devices.

There is a growing demand for positioning actuators with a higher resolution, accuracy, speed, and driving force. Various piezoelectric actuators have been proposed to meet these requirements; however, they all have inherent limitations. This paper presents a novel high-performance piezoelectric actuator that can overcome the limitations of existing designs. It is based on the stick–slip actuation principle and makes use of coupling motions of the proposed triangular driving mechanism to generate a clamping action during the “stick” phase and a releasing action during the “slip” phase. Unlike existing driving mechanisms based on similar principles, the proposed actuator can employ its unique structure to amplify the clamping force and the related driving force by using a large design triangular angle. Apart from its superior performance in driving force, it is interestingly found that its driving speed performance also improves when the design angle is increased. Finite-element analysis and experiments are carried out to justify the superior performance of the proposed actuator. In comparison with existing actuator prototypes based on similar principles, a prototype of the proposed actuator, even driven with a lower input voltage, achieves an 11 times larger driving load and a 3 times higher free-load driving speed. [ABSTRACT FROM AUTHOR]

This paper presents the design, analysis, and experiments of a novel stick–slip actuator with large working stroke and high resolution based on parasitic motion. To meet the requirement on large stepping-stroke in the fields of nanofabrication and nano-characterization, the bridge-type mechanism with asymmetric stiffness which changes the distribution of piezoelectric actuator elongation at two input points is proposed. A chain-based compliance matrix model is established for the static performance characterization and parameter optimization of the dual-input closed-loop compliant mechanism, and the performance is further studied by finite element method. The prototype of the proposed actuator is manufactured and experimental tests are conducted to investigate its characteristics. The results indicate that the maximum motion speed is 23.53 mm/s with the driving frequency of 350 Hz. The stepping-stroke is 102 μm, and the resolution is measured to be 12 nm. It is confirmed that the proposed actuator is feasible to enlarge the stepping-stroke and work stably. [ABSTRACT FROM AUTHOR]

• A novel rhombus-type displacement amplification mechanism is proposed. • A novel stick–slip actuator with symmetric structure is developed. • The motion speed and step displacement of forward/backward motion are consistent. • A new driving method in which two driving feet act together is proposed. This paper proposes a novel liner stick–slip actuator with compact structure which can achieve forward and backward motion. A novel rhombus-type displacement amplification mechanism (RTDAM) with symmetric structure is used to generate lateral motion to improve the actuator performance. Theoretical analysis and finite element analysis (FEA) are carried out to calculate the coupling ratio and natural frequency of the system. In addition, a new driving method in which two driving feet act together is proposed, which can improve the load capacity of the actuator. A prototype is fabricated and experimental tests are conducted to investigate its performance. The results indicate that the maximum speed of forward and backward motion are 428.5 μm/s and 443.2 μm/s, respectively. Compared with the single foot driving method, the load capacity of the actuator is increased from 1.2 N to 1.6 N by adopting the new driving method. Finally, a micropositioning stage is built utilizing the proposed stick–slip actuator and the experimental results indicate that the stage can work stably. [ABSTRACT FROM AUTHOR]

This paper provides a comprehensive review of the literature regarding actuator systems which are based on the principle that combines the friction and inertia effect, named friction-inertia principle in this paper; such actuators is called friction-inertial actuator (FIA). The contribution of this paper lies in the generalization of various published (including patented) FIAs into a general principle with three specific principles. They are further taken as a framework upon which various published FIAs are classified and compared in terms of their principle, structure, and performance. In addition, this paper shows how this framework would allow for further innovation on FIAs. In the process of this generalization and classification, some confusion presented in the literature is also clarified. This paper also discusses further effort that may be taken to advance the friction-inertia actuation technology. [ABSTRACT FROM AUTHOR]

Abstract: The Smooth Impact Drive Mechanism (SIDM) is a linear piezoelectric actuator that has seen practically applied to camera lens modules. Although previous SIDM actuators are easily miniaturized and enable accurate positioning, these actuators cannot actuate at high speed and cannot provide powerful driving because they are driven at an off-resonant frequency using a soft-type PZT. In the present study, we propose a resonant-type SIDM using a bolt-clamped Langevin transducer (BLT) with a hard-type PZT. The resonant-type SIDM overcomes the above-mentioned problems and high-power operation becomes possible with a very simple structure. As a result, we confirmed the operation of resonant-type SIDM by designing a bolt-clamped Langevin transducer. The properties of no-load maximum speed was 0.28m/s at driving voltages of 80Vp-p for 44.9kHz and 48Vp-p for 22.45kHz with a pre-load of 3.1N [Copyright &y& Elsevier]

Abstract: The article describes an analog electronic circuit for driving stick–slip piezoelectric linear actuators. The task for the amplifier is to provide a high-voltage asymmetric sawtooth-like signal and feed it into a capacitive load. Generation of excessive heat must be avoided while maximizing the slew rate. In order to guarantee a steady translation, the hysteretic behaviour of the piezoelectric material must be compensated. Combination of a charge control scheme with switching is proposed as an efficient solution. Laboratory experiments confirm the superiority of this tailored solution over other existing techniques based on versatile linear voltage amplifiers. [Copyright &y& Elsevier]

This paper proposes a new electrostatic impact drive actuator that is operated by a DC high voltage. In the actuator, a movable mass oscillates between two opposing electrodes such that it alternately collides against the electrodes. The collisions are converted into locomotion by the unique design of the electrode supports. The actuation principle is characterized by its simple structure, which would facilitate applications in special environments or miniaturization of the actuator. The actuator operation is modeled using an equivalent electric circuit that predicts the voltage variation and the corresponding motion of the movable mass. The theoretical prediction is verified using prototype actuators that demonstrate one-directional stepping motion with a step width of several tens of micrometers. The performance test on a slope shows that the actuator can climb a slope up to 5°. Another experiment to push an external load shows that the actuator can push a weight up to twice the actuator's own weight. [ABSTRACT FROM AUTHOR]

[Display omitted] • A fully-compliant stick-slip nanopositioner with error compensation is proposed. • Serial error compensation stage and model-predictive control approach are designed to achieve linear motion. • An experimental methodology is presented to validate the effectiveness of the nanopositioner in trajectory tracking tasks. • The proposed nanopositioner reduces stick-slip tracking errors by 86%. Nanomanufacturing and nanoassembly require positioners capable of producing nanometer order precision with millimeter order workspaces. Current nanopositioners are based on compliant mechanisms or stick-slip/inertial drives. Compliant mechanisms give ultra-high precision but small workspaces, while inertial drives are bulky, expensive, and induce large transient errors making them unsuitable for tracking motions. A compliant stick-slip nanopositioner with error compensation was investigated in this research. The compliant design has a range of approximately 960 μm, is simple to manufacture and is suited to miniaturization. A serial error compensation stage was developed using model-predictive control, which is demonstrated to compensate for stick-slip errors and enable linear motion. Compared to the uncompensated design, root mean square tracking errors were reduced by 86% using the model-predictive control strategy. Hence enabling precise, and long-range tracking. [ABSTRACT FROM AUTHOR]

• Proposing a novel driving method for piezoelectric stick-slip actuators. • Implementing the proposed cooperative compensation method (CCM). • Obtaining larger step size and faster output velocity using the CCM. • Reducing the requirement of using driving signals at high frequencies. With the development of micro-electromechanical systems, high precision actuators with high resolution, fast speed, large load capacity are increasingly required. Thanks to the characteristics of flexible structure, fast step speed, low energy consumption, high resolution and unlimited stroke range, stick-slip actuators have been drawing worldwide attention. Traditionally, stick-slip actuators are driven by sawtooth waveform signals with a slow increase and a fast decrease. Therefore, there is an unavoidable return stroke when fast decrease of the driving signal appears, which reduces driving speed and efficiency. In this paper, a novel cooperative compensation method (CCM) to compensate for return stroke of stick-slip actuators is proposed. It uses two signals of specific initial time gap (ITG) to reduce the return stroke to improve speed. A modified two-layer stick-slip piezoelectric actuator based on a triangular compliant driving mechanism is built. Experimental results show that the CCM can effectively increase step size of the actuator, especially driven under low frequencies. When signal is at 10 Hz, the step size of the actuator With CCM is over 29 times of that with traditional single-PSA-driving method (TSM). The maximum step size with CCM is 4.448 µm at 250 Hz, which is more than 40% of TSM. [ABSTRACT FROM AUTHOR]